U.S. patent application number 12/986640 was filed with the patent office on 2011-08-11 for temperature conditioning system method to optimize vaporization applied to cooling system.
Invention is credited to Moises Aguirre Delacruz.
Application Number | 20110192172 12/986640 |
Document ID | / |
Family ID | 45809545 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110192172 |
Kind Code |
A1 |
Delacruz; Moises Aguirre |
August 11, 2011 |
TEMPERATURE CONDITIONING SYSTEM METHOD TO OPTIMIZE VAPORIZATION
APPLIED TO COOLING SYSTEM
Abstract
Described herein is for a system and procedure to apply
vaporization for heat transfer processes, particularly condensers
in air conditioning and refrigeration systems both for upgrading
units using the discontinued R22 refrigerant and for new
equipments. The application can be applied to other cooling
processes such as computer chip cooling, garments for medical,
personal garments for military personnel. The application points to
the features of different manifestations of vaporization for
cooling in both natural and other equipments. The process can be
extended for small and compact implementation on new equipments
with maintenance improvement compared to water tower coolers, lower
capitalization costs, modularity and ease of maintenance, and
indoor installations enabling extension of capability of the
cooling system with application of air flow condition. The
advantages and implementation on new equipments for residential,
industrial and large cooling units enable several advantages both
economic, reliability, maintainability, indoor operation, reduction
of cost of scaling problems and flexibility. Many additional
applications are possible and are discussed herein, including high
power computer chip cooling.
Inventors: |
Delacruz; Moises Aguirre;
(Cottage Grove, MN) |
Family ID: |
45809545 |
Appl. No.: |
12/986640 |
Filed: |
January 7, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61335474 |
Jan 7, 2010 |
|
|
|
Current U.S.
Class: |
62/3.2 ;
62/171 |
Current CPC
Class: |
H01L 23/427 20130101;
F24F 2013/225 20130101; F24F 1/42 20130101; A41D 13/0053 20130101;
F28F 27/00 20130101; F25B 2339/041 20130101; H01L 23/34 20130101;
H01L 2924/0002 20130101; H01L 2924/0002 20130101; H01L 2924/00
20130101; F28D 5/00 20130101 |
Class at
Publication: |
62/3.2 ;
62/171 |
International
Class: |
F25B 21/02 20060101
F25B021/02; F28D 3/00 20060101 F28D003/00 |
Claims
1. A system to deliver water for vaporization and control of the
convection mechanism to transport the water vapor product for
cooling including: a. feedback control means on water delivery rate
for vaporization, b. control means of air flow for transport of
vaporization product, c. sensors to measure temperature and d.
means to control water delivery to provide water and fan speed to
effect the heat transfer utilizing only vaporization and avoiding
encroaching on heat transfer involving sensible heat of water.
2. The system of claim 1 further including a temperature sensor
that averages the temperature on the air flow opening.
3. The system of claim 1 further including water delivery means to
control the rate of drop formation.
4. The system of claim 1 further including water delivery means to
deliver and form a uniform water film on a hot surface.
5. The system of claim 1 further including means to control
scaling.
6. The system of claim 1 further including means for maintenance to
prevent reduction in efficiency due to scaling.
7. The system of claim 6 further including means to use ultrasonic
waves using scanning frequency of waveform drive together with duty
cycle to enable mechanical dislodge of small bicarbonate
deposit.
8. The system of claim 6 further including means for selection of
materials for tray and peg for the water distribution to have a
high contact angle.
9. The system of claim 8 wherein the materials are one of
polycarbonate and Teflon material.
9. The system of claim 1 further including air flow velocity
control to complement and/or function together with water deliver
control.
10. The system of claim 1 further including means to control the
air flow temperature by pre conditioning of heating and cooling to
minimize air flow for transport by convection and reduce size of
heat transfer structures.
11. The system of claim 9 further including means to arrange
sections of a condenser to operate in either air or water vapor for
transport mechanism by using sensible air flow from air convection
section to precondition air flow for efficient vaporization process
with other section if a compromise on full benefit of vaporization
under some ambient operating conditions.
12. The system of claim 10 further including means to pre heat air
for computer chip cooling.
13. The system of claim 10 further comprising means to pre
condition air for computer chip cooling using Peltier heating and
cooling semiconductor device.
14. The system of claim 1 further comprising means to pre condition
air for large cooling loads using vaporization.
15. The system of claim 1 further comprising means to have
distributed cell condenser modules on very large capacity cooling
systems to minimize system downtime.
Description
CROSS REFERENCE RELATED APPLICATIONS
[0001] This application has priority to currently pending U.S.
Provisional Application Ser. No. 61/335,474 filed on Jan. 7, 2010
titled TEMPERATURE CONDITIONING which is hereby incorporated by
reference in its entirety.
FEDERAL SPONSORED RESEARCH
[0002] None
SUMMARY
[0003] This application is a method to optimize the application of
vaporization for cooling purposes. The process is applied in this
application for upgrades on air conditioning and refrigeration
systems to improve efficiency with extension of the performance on
the effect of ambient environment temperature and humidity. This
feature would yield a significant improvement in energy usage in
locations where the temperature and humidity are high where the
equipment undergoes very high usage. The added cooling capacity due
to the improvement in efficiency could be strategically used to
improve comfort level with the attendant advantage of reducing
energy because of the possibility of raising the temperature
control setting.
[0004] The process also is applicable to new equipments where the
new refrigerants and techniques are applied. Application of the
process for these higher efficiency units benefits at a higher rate
than the upgrade by the ratio of the COPs of the new to the old
systems.
[0005] Application to new systems results in reduction in initial
capitalization besides the savings on recurring cost and
maintenance cost. Another embodiment presented for this cooling
process is to improve performance and maintain reliability of
computers, both personal and supercomputing architectures by
cooling the computer chip.
[0006] The known practical limitations of vaporization are
addressed in the process. Vaporization of water applied to cooling
processes is accompanied by scaling. Scaling is the buildup of both
bio film and carbonate deposits in slow water flow around heated
surface of metal. The process decreases and simplifies the
maintenance requirement due to scaling because of metering of the
water delivery for vaporization.
[0007] The process results in the following benefits. The
efficiency for cooling, the reduction of scaling with improvement
in both economics and logistic of maintenance, extension and
improvement of the range of ambient environment conditions for the
air conditioner or refrigeration systems and the computer chip
cooling. The process introduces other control parameters that
enable the capabilities mentioned. In particular, this application
presents an airflow temperature and humidity control such that the
limitations because of ambient temperature and relative humidity to
perform required cooling especially for large loads are alleviated
with further improvement in system efficiency. The reduction in the
demand for air flow enables bringing the condensing equipments
indoor and enables other control strategies to achieve system
efficiency, maintenance, reliability performance.
[0008] This application is for a procedure to apply vaporization
for heat transfer processes, particularly condensers in air
conditioning and refrigeration systems both for upgrading units
using the discontinued R22 refrigerant and for new equipments.
[0009] The application can be applied to other cooling processes
such as computer chip cooling, garments for medical, personal
garments for military personnel.
[0010] The application points to the features of different
manifestations of vaporization for cooling in both natural and
other equipments. The embodiment cited for upgrade of air
conditioning and refrigeration systems that are using R22 and other
refrigerants. These are refrigerants disallowed for new equipments
by EPA. The process is discussed in detail to show the effective
improvement in efficiency, cooling capacity, ambient temperature of
operation. The process can be extended for small and compact
implementation on new equipments with maintenance improvement
compared to water tower coolers, lower capitalization costs,
modularity and ease of maintenance, and indoor installations
enabling extension of capability of the cooling system with
application of air flow condition.
[0011] The advantages and implementation on new equipments for
residential, industrial and large cooling units enable several
advantages both economic, reliability, maintainability, indoor
operation, reduction of cost of scaling problems and
flexibility.
[0012] The implementation of the whole gamut of listed advantages
presupposes the development of embedded controllers and digital
interface devices for sensors, drives and communication.
[0013] The other embodiment is for high power computer chip
cooling. The embodiment on computer chip allows the cooling of 1
kilowatt per square centime computer chip heat dissipation with
reduced air flow volume and heat sink physical volume.
[0014] The application is on heat transfer. The process is an
optimization procedure for the heat transfer that uses the common
processes of conduction, convection, radiation and reflection.
[0015] Conduction is the process by which the energy of a source
which is usually manifested by the temperature of the material is
routed out via the material or other materials through the passage
that allow the energy in the form of "heat flux" to the recipient
or absorbing material. The process is dependent on the material
property of thermal resistance which is inversely proportional to
the area the flux would flow and the length of the path or thermal
path.
[0016] Convection is the actual transport of materials that have
acquired the energy from the source. The transport of the material
enables the flow of the heat flux. The usual convection medium is
air where the air around a highly conductive material like the
enclosure for the refrigerant acquires the heat energy by
conduction. The thermal resistance of the air and also the specific
heat which is the amount of energy needed to raise its temperature
one degree per unit weight is relatively low. Therefore the method
of convection demands a large amount of air mass to be
transported.
[0017] Radiation is a transport phenomenon similar to the
convection process. However in this case, there is no material that
is physically transported. The energy of radiation is in the form
of electromagnetic waves that is able to be conveyed even in vacuum
or space. The energy is manifested and proportional to the fourth
power of the temperature of the source.
[0018] The application shall discuss only the conduction and
convection heat transfer process. The convection process uses water
as the transport material.
[0019] The vaporization of water has been applied for cooling for
over several decades in air conditioners and refrigeration
equipments. Vaporization is also a natural phenomena associated
with our weather and life on earth. The vaporization in vegetation
and open waters are primary contributors for our weather.
[0020] The vaporization of water involves a large amount of energy.
Under the usual situations where the pressure is at one atmosphere,
the amount of energy to vaporize a gram of water is 2260 joules.
This is quite significant when compared to the sensible heat needed
to change a gram of water by one degree centigrade, which is 4.18
joules per gram per degree C. In the case of air, the sensible heat
absorbed by air is very small, 0.001 joules/cubic centimeters. FIG.
(3) shows the typical topology of cooling a material. It uses
material property that enables the diffusion of heat energy along
the material. The degree of efficiency of conduction is determined
by the thermal conductivity path from the material to be cooled to
the next material. This metric is dependent on the material and the
physical dimensions. In particular metals are very good heat
conductors and the heat flux is improved by increasing the area for
which the heat flux flows and by reducing the length of the path
involved in the flux passage. The second normal medium is air
because it serves as a medium of transport for the heat energy to
the ambient environment by convection. The higher temperature from
the "heat sink" is acquired through the conduction of heat from the
metal surface to the air. This starts the diffusion process. The
region between the heat sink to the distance where the ambient
temperature is acquired is usually called the boundary layer. This
layer under steady state conditions establishes the effective
thermal conductivity from the second interface to the ambient air.
Since the boundary layer is air which has very low thermal
conductivity, the effective resistance of the boundary layer is
large. The high thermal resistance of the boundary layer is
minimized by modifying the thickness of the boundary layer. This is
achieved by the process of convection where air flow with ambient
temperature reduces the thickness of the boundary layer by removing
the warm material on the boundary layer. The boundary layer is
between the surface of the metal surface and the edge where the
boundary layer reaches the temperature of the ambient air
temperature. The boundary layer temperature profile is dependent on
the effective diffusion process modified with the convection
transport mechanism. If the diffusion gradient is maintained with
the air flow, then continuous higher heat flux flow occurs. The
efficiency of removing the warm air from the boundary layer is
obviously dependent on the velocity of the air flow and the
temperature difference between the second interface and the ambient
temperature. The practical limits therefore are the effectiveness
of the air flow for removing the heated mass of air. This affects
the efficiency of the system because a higher air flow means more
power usage for the fan. Raising the air flow velocity causes
higher noise levels.
[0021] The resulting thermal resistance of the boundary layer
imposes practical limits for higher cooling capacity. For example
computer chips need cooling requirements around 150 watts. The
silicon chip technology is improving and following Moore's law on
speed and feature sizes. At present, the power levels that is
possible with the feature sizes of the silicon devices developed by
the technology and the natural desire to integrate as much as of
the system in the chip is predicted requires at least 1 kilowatt
per square centimeter for cooling. The present cooling towers that
require cooling for 150 watts and uses heat pipes and fins that
occupy over 100 cubic inches with attendant noisy fan for air flow.
The present technology for the cooling requirement would demand a
large mass of air to transport the needed heat and larger physical
size and other complication plumbing if heat pipes were applied.
The application addresses these practical problems.
Processes Using Vaporization for Cooling
[0022] This application is the process of modifying the process
discussed above with the use of water as the medium that is created
and removed from the boundary layer. The process applies a similar
structure as used in prior art technology of using conduction and
convection of air to convey the heat energy absorbed with the air
flow to the environment. The specific heat of the air is 0.001
joules per cubic centimeter. Water when vaporized to form the
boundary layer extracts 2260 joules per gram for cooling. The
process uses water that is vaporized by the introduction of water
on the interface from the high conductivity heat sink to carry the
heat energy to ambient environment. The vaporization of water
involves the large heat and requires only a small amount of water
to support the cooling process. For example, if the heat sink is to
provide cooling for one kilowatt, the water needed is less than one
half (1/2) grams per sec. Air however can support a limited amount
of water vapor that is dependent on the air temperature. The
capacity of air to support water vapor product of cooling is
limited and increases as an exponential function of
temperature.
[0023] The process of vaporization is the separation from the
liquid to vapor of very high energy molecules. The rate by which
this occurs is dependent on the temperature. The temperature
establishes the density or the vapor pressure created from the
surface of the water film at the given temperature. The vapor
pressure created at the immediate boundary from the source of heat
to the air continues receiving higher energy molecules up to the
level determined by the saturated capacity of the air. At this
state, the amount of molecules leaving the liquid state are the
same as the amount converted back to liquid. The relationship
between the maximum water vapor content for a cubic meter of air is
called saturated humidity and is dependent on the air temperature.
The relationship is exponential with increasing temperature. FIG.
(1) shows this relationship. When the saturated condition of the
water vapor is reached, the heat flux is reduced. If the container
is enclosed, the heat flux completely stops because there would be
zero net transformation of water molecules from one phase to the
other. If the environment is not enclosed, the boundary layer
laminar sheets undergo diffusion process because the concentration
of water vapor immediate to the heat source is much higher
initially than the succeeding layers from the metal or water film
surface. The water vapor in the air is usually lower than the
maximum it could support called the saturation content. The ratio
of the water vapor to the saturated level is called the relative
humidity. The dew point of air is the temperature where the water
vapor content starts condensing, that is when the water vapor
content of the air is equal to the saturated air. FIG. (1) shows
the saturated humidity and also the amount of water vapor available
before saturation when the relative humidity is 40%.
[0024] If one were to assume for example initially that the next
layer to the saturated layer from the water film were at the vapor
pressure corresponding to the incoming air flow then a large
difference would exist because of the probability that the
immediate surface to the water film would be saturated. This
difference in vapor pressure creates effective diffusion mechanism
where the water vapor content on the immediate area from the water
film surface migrates to the lower water vapor density layers. This
process continues outwards perpendicular to the surface until the
steady state boundary layer is established and the heat flux flow
is dependent on the vapor pressure gradient created by the
diffusion. This is dependent again on the corresponding difference
between the saturated vapor pressure at the temperature and the
vapor pressure presented from the ambient air flow. Note that the
transport of the water vapor to create the heat flux flow is not
dependent so much on the temperature but primarily on the vapor
pressure gradient along the flux path. The main parameter is that
the diffusion gradient is established and determines the capability
of the supporting heat sink circuit to convey the heat flux. When
steady state is reached without air flow, the air chamber would
reach the same temperature as the heat sink interface. The
introduction of air flow to facilitate convection removes the water
vapor from the chamber. This completes the flow of heat flux from
the heat source to the ambient environment. This is enhanced when
there is convection to transport of vaporized water. The air flow
removes the vapor material in the chamber and creates a thin
boundary layer between the heat sink and the incoming air flow. The
boundary layer is sustained with higher continuous heat flux from
the saturated interface of the water from the heat sink when the
boundary layer gradient is maximized. If the heat flux increases,
the vapor gradient has to correspondingly increase such that the
flux is accommodated. The air flow therefore has to be high enough
such that the vapor generated does not accumulate to the level of
degrading the heat flux flow needed. The process is dependent on
the diffusion created by the difference in vapor pressure or
gradient of the water molecule concentration starting from the
interface to the effective region where the air flow transports the
water vapor. The thickness of the boundary layer is reduced
depending on the air flow velocity. This improves the efficiency of
transporting the water vapor cooling product. The diffusion process
implicitly creates a temperature gradient. However the magnitude is
minimal. Thus the difference in the sensible temperature change
between the heat sink interface and the output air flow is small.
The diffusion process has a time constant. It is possible that the
immediate surface of the water film might not be completely
saturated if the air flow is such that the vaporization time
constant cannot be supported by the rest of the thermal
circuit.
[0025] FIG. (2), FIG. (2a), FIG. (2b) show the physical
relationship between the fins, the water film, boundary layer and
the effect of air flow velocity. In FIG. (2, 10 is the fin
structure at a distance of qfin from each other. 12 is the water
film and 16 is the boundary layer region. 14 is the midpoint of the
fin separation. q(0) is the saturated vapor pressure heat flux flow
at the interface of the water film and start of the boundary layer.
qin(x) shows how the heat flux along x distance from the fin in the
boundary layer. Together with qout(x) and qflow(x) are the
variation of the heat flux at x when the air flow removes the heat
flux qflow(x). The laminar velocity profile of the air flow which
has a maximum velocity Vmax is shown in FIG. 2a. Note that the
velocity close to the water film is small and the vapor gradient is
very high. The total of qflow(x) over the boundary layer is under
continuous heat flux flow equal to q(0). In FIG. 2a 18 shows the
condition and the width of the boundary layer 16 for a volume rate
of air flow. 20 is airflow that is adjusted lower than on 18. Note
the reduction in the boundary layer thickness with higher air
velocity 18. When the cooling load increases such that q(0)
increases, 18 changes closer to the profile 20. Thus for much
larger loads where the boundary layer increases towards the center
of the fin separation, there is the necessity to increase the air
flow. The boundary layer has the limit for a vapor pressure profile
where the middle of the fin spacing is such that the vapor pressure
there corresponds to the saturated vapor pressure for the ambient
air temperature. If more flux has to be maintained then the heat
flux will manifest itself in the material as sensible temperature
across the boundary layer. One can say therefore that the maximum
temperature change across the vapor boundary layer would have a
profile where the heat flux that is needed to be carried together
with the air flow relative humidity and velocity would result in a
saturated condition across the whole boundary layer. Otherwise
beyond that air flow transport mechanism would involve sensible
heat process which would increase the air flow temperature. To
sustain the heat flux of q(0), the airflow over the boundary layer
should extract the total of q(0).
[0026] FIG. (1) and also FIG. (3) shows the increase in the
saturated water vapor capacity of air with temperature. The
equation came from the NOAA branch of the federal government. FIG.
(1) also shows the remaining water vapor that can be contained with
the same volume when air has the relative humidity of 40%. FIG. (3)
shows the comparison of saturated water vapor and relative
humidities of 40% and 75%. The other curve shows the effect of
heating the ambient air when it is low (68 F) to a higher
temperature to open up more capability for air to absorb water
vapor. Heating has to be performed without undue acquisition of
water vapor.
[0027] The criteria above on sensing the inception of sensible heat
mechanism in the boundary layer as the increase of air flow
temperature will be used for a sensing mechanism to generate
feedback signal for the water delivery controller to optimize the
contribution of the transport mechanism using vaporization.
[0028] FIG. 2a assumes that the relative humidity of the incoming
air is constant. If the relative humidity gets lower, then the
boundary layer gradient profile will be steeper. This means that
the cooling capacity would be higher because it will take more heat
flux to bring the boundary layer edge to the midpoint of the fins.
Note that when there is no air flow, the development of the
diffusion vapor pressure gradient is that in steady state, the
space between the fins would acquire the same temperature as the
source of heat. On the other hand, it is possible that the
temperature of the water film interface vapor is at a lower
saturation because of the time constant for vaporization and
attendant diffusion process.
[0029] The practical air flow velocities under the aesthetic and
power constraints are usually such that it would be laminar. The
laminar profile of air flow is characteristic of the velocity at
the immediate heat source surface is almost zero increasing at
parabolic rate to its maximum at half the distance of fins. Since
this is the highest concentration of the water vapor, then a little
higher air flow than what would calculate to have an effective mass
flow transfer is needed. Nevertheless because of the large energy
for vaporization, the amount of air necessary to convey the water
vapor is less. Since the boundary layer could be designed with the
airflow control to be thin, then the effective "thermal resistance"
of the boundary layer is minimal. The contribution of heat flux
flow because of the thermal resistance is negligible compared to
the heat flux because of the transport of the created water vapor.
This means that the "temperature head" on the boundary layer in the
air medium for convection is significantly higher than the
resulting "temperature head" with the water vapor as a transport
material for convection. The resulting improvement on the
"temperature head" allows lowering the temperature at the computer
chip and increases its reliability.
Examples of Natural Vaporization and Other Applications on Cooling
Equipments Using Vaporization
[0030] The following are manifestations of vaporization in both the
natural environment and also in some cooling practices. We shall
discuss them to emphasize the differences and point the main
factors affecting the efficiency of the processes.
[0031] The flow of heat flux is a circuit where the heat source,
usually at a higher temperature generates diffusion to transport
heat from the source down the thermal circuit. The magnitude of the
heat flux would be dependent on the resistance presented by the
materials along the circuit to the flow. This is called the thermal
resistance of the material. It is a physical characteristic of the
material and also dependent on the topology. There could be several
materials involved along the thermal circuit before the heat flux
is conveyed to the water film as shown in FIG. (8). Thermal
efficiency using the water for vaporization is to maintain the
capability to support the vaporization from the water film by
sufficient heat flux flow.
[0032] The process of vaporization is when liquid water changes
from a liquid state to a vapor state and is called either
transpiration or evaporation. The term is mostly correlated with
the system. Vegetation vaporization which is one of the main
contributors to our weather is usually called transpiration. The
term could be applied to processes where the water source is
introduced to the vaporization process through small pores or
channels from other materials.
[0033] It is my opinion that the difference is whether the liquid
water is introduced to acquire the energy from some controlled
enclosure or available in open environment. For our purposes here I
will not distinguish the terms and use vaporization.
[0034] Transpiration is the term used on vaporization in
vegetation, FIG. (4) shows a schematic on the vaporization. The
energy from the sun 44 maintains the temperature on the surface of
the leaves and around the immediate area of the leaves. These are
balanced by the natural properties of color, stomata reactions,
wind to achieve an energy balance. The water from the roots rises
up by capillary action through tubes 46 to the leaf structure and
exposed to the atmosphere by the opening of the stomata pores on
the leaves. The water within the leaves chamber has established
saturated vapor pressure. When the stomata 42 opens, the leaf
opening chambers 40 are exposed to the lower concentration of water
vapor in the immediate surface of the leaves and enables
vaporization. The vaporization process is controlled by the
vegetative plants in response to its need. The response of the
leaves is dependent on the available energy from the sun and also
the transport mechanism on the resulting boundary layer by wind
action. The vaporization process effectively reduces the
temperature of the air around the general area of the tree or
vegetation. The transpiration process allows the vegetation to
undergo photosynthesis with the attendant transformation of sun's
energy into the vegetative materials from which we get our food,
air to breathe and among others control our weather. It needs to be
pointed out that the temperature inside the leaf where the
saturated vapor barrier is generated before the stomata opens could
be at a lower temperature than the ambient air. This is true
provided the vapor pressure of the ambient air is lower than the
saturated vapor barrier when the stomata opens. This is magnified
when wind blows to carry the vapor materials out and lowers the
boundary layer thickness. In nature, the requirement for vegetation
for the magnitude of vaporization is small (typically 0.7
grams/day),
[0035] The energy from the sun 50 is absorbed by the water body in
open areas. FIG. (5) shows the sketch of the vaporization for open
surface or water. Some molecules of water have more energy and able
to escape and form a vapor barrier above the surface. There is also
at the same time energy extracted from the air above the water
surface qair but because of the relatively larger thermal
resistance to the air, most of the vaporization energy qflux is
taken from the water. The vaporization process continues to steady
state conditions depending on the effective "thermal resistance" on
the boundary layer. The boundary layer is maintained such that a
continuous vapor qflux is sustained. This is the limiting rate by
which vaporization occurs. The vapor pressure gradient of this
layer could be altered by wind motion above the surface and the
variation in temperature of the air. In most cases the heat of
vaporization is manifested with small amount of sensible heat
temperature changes but mainly by vaporization that is aided
considerably by the vapor transport with wind action.
[0036] Evaporative coolers or swamp coolers shown in FIG. (6),
These are economical and effective cooling equipments especially in
low humidity and high temperature environments, The block diagram
of the equipment is shown in FIG. (6). 50 is a fan enough to
provide sufficient air flow through a porous mesh usually made of
fibrous tree material 52 that allows distribution of water
uniformly on the pad. The air from the blower 50 serves both as the
boundary layer that forms when the fan changes the water into mist.
Also it might carry some particles of water to the ambient
environment where the velocity of the water droplets has the
eventual falling and route exposed to the environment for the
extraction of the material around the boundary layer of the
droplets. Notice that the effective thermal conduction at the
boundary layer is not consistent. The movement of the spray drop
from the equipment provides the air flow discussed above to create
a low thermal conductivity. The velocity of the water drop as it is
generated by the misting process effectively provides the
convection to remove the water vapor on the water drop surface.
Also the relative humidity of the air increases and affects the
effectiveness of vaporization because of the attendant increase in
relative humidity. The increase in water vapor in the area affects
the comfort level in spite of the reduction of the temperature. The
efficiency is low because it is hard to control and direct air flow
to be able to create the complete vaporization of the water mist.
This leads to high water usage and also energy for the fan.
Nevertheless under environments stated above of high temperature
and low humidity, the economic benefits and added comfort levels
overcome any efficiency issues. The effectiveness of these devices
are dependent on low relative humidity environments that is capable
of absorbing large amount of vapor for cooling without affecting
the relative humidity and comfort zone in the area.
[0037] FIG. (7) is the sketch for water tower cooling. The heat
exchanger 54 is a water tank surrounding the labyrinth of pipes
containing the refrigerant circulating through pipe 66. The slow
water flow together with the relatively high thermal conductivity
of the water intimately in contact with the refrigerant enclosure
walls enables relatively efficient heat flux transfer. The heat
from the refrigerant is routed to the water tower with the transfer
pump 56. The warm water is sent to a system that drops the water
from 58 into skids or crates 60 that mechanically present the water
to the high velocity air from the fan 62. Water from the skids and
crates form water fall of droplets falling again the air fan blown
air. The droplets have the vapor barrier around and these are
exposed for removal with the relative motion of the air flow from
the fan 62 and the fall with gravity.
[0038] The system is an effective cooling system that has drawbacks
on optimizing the potential of vaporization. The heat flux has to
be conveyed from the refrigerant to the refrigerant enclosure. From
the enclosure the next thermal component is the transfer from the
enclosure to the water. The transfer is improved because of the
velocity of the water across the enclosure tubes carrying the
refrigerant The flow of water is routed to water skid crates that
creates films of water to the air flow from either an air flow fan
above or below the water cooling tower. The efficiency of the
implementation is dependent on the flow of heat from the
refrigerant to the water for vaporization. The present
mechanization for taking advantage of the large latent heat of
phase change for water is not optimized. There are a number of
materials from the refrigerant to the introduction of the water
film for vaporization. This lowers the available saturated vapor
pressure on the water film. The thermal circuit consisting of the
following accumulates and increases the thermal resistance from the
refrigerant to the presentation of the water for vaporization. The
heat flux flow and the resulting temperature drop is significant.
Thus at the transition where the liquid water is presented for
vaporization, the effective vapor pressure which is dependent on
the temperature has decreased from the temperature of the
refrigerant. Also there is a net result of wasted air flow energy
because the air flow is not focused on the boundary layers. The
effectiveness of concentrating the fan energy to carry as much of
the vaporized material as possible is not optimal Another practical
issue is that since the usual manner of water delivery exposes the
material to ambient air especially at the water tray 64 results in
the accumulation and increase in bio film enabling materials and
organisms. Bio film scaling is product of interaction of bio
components with the water to cling in an ionic manner to the metal
surface. This is affected because of the high temperature at the
surface together with the low water flow velocity giving the ionic
process time to be effective. Bio film buildup is usually the
precursor to the formation of permanent adhesive materials for
further scaling from other sources like carbonates from the water.
The initial bio film serves as initial anchor for the carbonates
and has the property that after a certain threshold in time, the
permanency of the adhesion to the metal surface increases
exponentially. This leads to the acceleration of degradation of the
thermal conductivity of the transfer of heat from the refrigerant
to the water medium. Expensive total downtime for maintenance of
the system therefore is an economic and logistic issue.
DETAILED DESCRIPTION
[0039] The process in this application consists of several
procedures that is to maximize the tremendous cooling capacity of
vaporization when used as a transport medium for convection. FIG.
(8) represents a general thermal circuit in terms of possible
topology for the heat flux path for presentation to the water film
for vaporization. The thermal circuit shown could represent the
various topologies possible in the creation of a flux path for the
heat flow from 80 the refrigerant to the ambient environment 78.
The different contributors to the thermal circuit are shown to be
82 as a series component, 70, 72, 74 as parallel components
configured to form an equivalent component, 84 as another series
component. 74, 88, 86 is a general representation on how the water
film maybe introduced to enable vaporization. 88 could be
eliminated. It is shown here to represent a water delivery topology
where the water chamber 76 acquires the heat energy from the
previous materials and creates the water film on the other side of
88 if 88 is a porous material that has microchannels that allow
water to move from 76 to the water film area 86. This type of
topology is used for example in water cooling jars prevalent in
South East Asia and also presented as a possible embodiment in the
computer chip cooling. The different material medium that are in
"series" or "parallel" are indicated. The main objective is to
minimize the accumulation of material contributions to the net
thermal resistance from the source to the water film. The procedure
of optimizing the thermal conductivity of the usual metal container
or transfer material to maximize the heat flux is very well known
and understood. The thermal conductivity of metal, e.g. copper is
400 while the thermal conductivity of water is 0.6 watts/m/sec. One
can see that assuming the areas involved are the same, the ratio of
the thickness of the copper to the water film would be 666:1
(400/0.6) for both to exhibit the same thermal resistance. Thus
water film thickness of 1 mm would have the same thermal resistance
as copper with thickness of 66.6 centimeters. The process therefore
would require that the water be delivered to the warm surfaces such
that the effective water film is as thin as possible. Vaporization
with convection results in minimal temperature change within the
boundary layer.
[0040] Metering of the amount of water delivered so that only the
required cooling requirement is delivered would use the measurement
of the temperature rise from the incoming air flow for the
condenser fins to the outgoing air flow temperature. Since the
process of vaporization with convection results in minimal
temperature change (mainly to establish the boundary layer
gradient), then metering could be implemented as a feedback control
system where the water delivery is enabled only when the output air
flow temperature is very close to a certain threshold to the
incoming air flow temperature. The threshold as a control parameter
indicates the approach of the air flow to vapor saturation with the
start of the sensible heat transfer. The value of the threshold is
a subjective decision for the designer or user. It could be before
or after the inception of sensing the saturation of the air. The
magnitude and effectiveness of vaporization is both affected by the
water delivery and the transport mechanism of convection. In
upgrades, since the fan has a fixed speed, then the remaining
control parameter is the water delivery rate.
[0041] FIG. 9 shows the general structure of the cooling equipment.
The temperature of the incoming air is measured with sensor 90 and
the temperature of the outgoing air is detected by an identical
sensor 92. Direction of air flow is shown by the arrow bands. FIG.
9a shows the possible arrangement of the sensor so that an average
function of the temperature within the air flow area is measured in
an averaging process. 90 and 92 are coils made of a very controlled
length and diameter wire routed around as shown in FIG. 9a. The
routing would follow the consecutive numbers and their position.
There could be some other more practical implementation but there
it is preferred to have some averaging capability. If there is
assurance that there could be no physical elements affecting
location of single point temperature sensors, then the average can
be done with an electronic filter circuit or in the case of
embedded controllers as a digital filter. Since the wires of the
coils 90 and 92 are identical then their resistance are identical
at the same temperature. FIG. (10) is an implementation of a
possible circuit block diagram to perform the feedback mechanism
for maintaining the closeness of the two temperatures sensed by 90
and 92. 102 and 102 are very accurately controlled current sources
that provides constant current under all conditions to the
temperature sensors 90 and 92 that are exposed to the area for the
input and output air flow. If there is a difference in temperature
measured by 90 and 92 then the differential amplifier 110 measures
and amplifies the difference. It is sent to the controller circuit
112 which could be implemented in various manners. For example, it
could be a similar circuit to a switch mode forming signal. The
energy for the driver would be in the form of a signal that is
repeated at a certain frequency adequate to support the maximum
drive needed. The duration of time during each initiation of power
is controlled and called the duty cycle. Modulating the duty cycle
would control the amount of energy flow to the motor driver 114.
The duty cycle and the frequency generate the necessary signals to
drive the peristaltic pump motor 116 for either clockwise or
counterclockwise rotation. The peristaltic pump motor 116 is with
the water tank for the water delivery metering process.
[0042] There is an added benefit to the metering of precise water
requirement for cooling because it automatically retards the
occurrence of bio film scaling buildup on the metal surfaces. In
ordinary heat exchangers, bio film buildup occurs because of the
presence relatively slow velocity continuous water around the metal
surfaces. The slow moving water with the high temperature result in
the formation of bio films on the surface of the metal. These
present themselves as anchoring points also for the accumulation of
carbonate deposits. The combination leads to expensive maintenance
of cooling systems. The metering of the water avoids the presence
of continued liquid water that enables the formation of bio film.
The metering also enables prediction of the magnitude of carbonate
scaling buildup with knowledge of the hardness of the water. This
would result in a logistical maintenance strategy since the extent
of degradation of thermal conductivity is predictable to the level
that the economic benefits could be maximized.
[0043] The other aspect pointed by the process is that the vapor
barrier gradient in the boundary layer has to be optimized such
that the heat flux is maintained at the maximum where the initial
vapor pressure at the immediate water film boundary. The high vapor
gradient should be maintained by the effective removal of the water
vapor. This involves adjusting the air flow such that with the
laminar flow it is sufficient to carry most of the material within
the quadratic profile inherent with laminar flow. It is desirable
therefore that the chamber for the air passage have minimum
thickness. This however could lead to higher velocity and more
noise. There are some cases where the topology of the presentation
of the water film to the air flow is such that turbulence along the
length of the air motion is possible. This would be effective in
getting the vapor barrier gradient very steep and improve diffusion
mechanism.
[0044] FIG. (1) shows that the amount of saturated water vapor at
low temperature is relatively small. The cooling capability is
limited at low ambient temperatures because of the available water
vapor capacity of the air. When the magnitude of cooling required
is large the need for high heat flux then the needed higher water
vapor is limited by the ambient air temperature. In the case of the
air conditioners, the temperature of the refrigerant on the
condenser is high. The ambient temperature of the air when the air
conditioner is needed is usually at a temperature where there is
adequate room for the air to accommodate the needed vaporization
for cooling. Therefore, the normal ambient temperature for
condensers operations in air conditioners allow vaporization to
work effectively for the power level and the present topology of
the condenser fins and tubes. The condensers used for refrigeration
however would operate under lower ambient temperatures. The limited
volume of water vapor that could be supported by air at the low
temperature for high cooling loads are degraded. Notice that the
vaporization process is such that the heat source temperature will
be almost the same as the ambient temperature air flow because of
the low thermal gradient of the boundary layer. This means that if
vaporization of applied to the level that it is the complete
process for cooling the condenser, then the condenser refrigerant
temperature is almost very close to the temperature head between
the refrigerant and the enclosure. The limited water vapor capacity
at lower temperature could be increased by raising the resulting
temperature head higher than the ideal mentioned. The temperature
is almost close to the temperature head of the refrigerant to the
enclosure. Under this situation, the immediate compensation is to
adjust air flow volume rate. This could lead to higher noise level
and demand from the fan. However with upgrades, air flow
adjustments are not available. FIG. (3) show that warming up the
incoming air flow temperature would raise the capability of the air
to sustain and support the higher vapor pressure product needed for
the cooling.
[0045] The heating process for the incoming air flow could be done
several ways.
[0046] One way would be to use the actual condenser cooling process
to be adjusted such that sections of the condenser would operate
the usual convective process with air as the transport material.
The output air flow from that section of the condenser with the
increase in sensible heat is used for the air flow need on the
section of the condenser that will utilize the vaporization
process. Since the sensible convection does not affect the amount
of water vapor, the output would have lower relative humidity at
the raised temperature. For example, in air conditioner condensers,
part of the fins and tube system modified in an arrangement where
the incoming ambient air does not make use of vaporization and
stays on the sensible region for heat exchange. The heat is
absorbed by the air and is manifested as an increase in
temperature. The output air can now be routed mechanically to the
other sections of the condenser where vaporization cooling
mechanism is implemented.
[0047] When the air flow through 110 fins, it has an increase in
temperature because the transport mechanism is air and would have
an increase in sensible temperature. This output air flow is now
used for 112 section of the condenser where the vaporization
procedure is applied with the water delivery implemented through
the valve 114.
[0048] Another process would be to preheat the air with
controllable power source.
[0049] Another would be to use hybrid of the two methods to obtain
the flexibility that might be required in some systems. The
procedure is discussed in the third embodiment.
DETAILED DRAWINGS
[0050] FIG. (1) Graph of saturated air of temperature F
[0051] FIG. (2) FIG. (2a), FIG. (2b Heat flux and air flow at the
boundary layer
[0052] FIG. (3) Graph of saturated air and emphasis of warm air
allowing more cooling capability
[0053] FIG. (4) Sketch of transpiration in vegetation
[0054] FIG. (5) Sketch of evaporation in open water
[0055] FIG. (6) Sketch of vaporization in swamp coolers and
evaporative coolers
[0056] FIG. (7) Sketch of vaporization in water tower coolers
[0057] FIG. (8) Sketch of general material path for heat flux to
the water film for vaporization
[0058] FIG. (9) Diagram of location air flow sensor
[0059] FIG. (9a) Sketch showing averaging with topology of
construction of temperature sensor
[0060] FIG. (10) Block diagram of water metering control circuit
using temperature sensors and pump
[0061] FIG. (11) Block diagram of air pre conditioning by using air
flow from condenser that uses sensible heat of air for convection
transfer
[0062] FIG. (12) Sketch of how vaporization is created to show
components
[0063] FIG. (13) General block diagram of vapor compression and
recovery system of cooling
[0064] FIG. (14) Phase diagram for R22 to show operation within
saturated region
[0065] FIG. (14a) Magnified phase diagram on the compression
cycle
[0066] FIG. (15) Phase diagram for an actual AC system indicating
non ideal operation
[0067] FIG. (16) Magnified phase diagram for an actual AC system
with pressure and enthalpy
[0068] FIG. (17) Phase diagram for an actual AC system with
vaporization process applied
[0069] FIG. (18) Phase diagram for actual AC with vaporization
applied (pressure vs. enthalpy)
[0070] FIG. (19) Water delivery block diagram
[0071] FIG. (20) Water delivery tray
[0072] FIG. (20a) delivery to implement uniform water droplet
distribution
[0073] FIG. (21) Block diagram of general implementation of
vaporization and pre conditioning on upgrades
[0074] FIG. (22) Implementation of upgrade without air pre
conditioning
[0075] FIG. (23) Implementation of upgrade with air pre
conditioning
[0076] FIG. (24) Block diagram of upgrade with maximum flexibility
on air flow pre heating
[0077] FIG. (25) Alternative implementation using spray nozzles as
alternative to water delivery trays and pegs
[0078] FIG. (26) Sketch of top view (orthogonal drawing) Computer
chip heat sink
[0079] FIG. (27) Sketch of front view (orthogonal drawing) Computer
chip heat sink
[0080] FIG. (28) Sketch cross section of heat sink 1.sup.st module
(looking down)
[0081] FIG. (29) Sketch cross section of heat sink 1.sup.st module
(middle)
[0082] FIG. (30) Sketch cross section of heat sink 1.sup.st module
(looking up)
[0083] FIG. (31) Sketch cross section of heat sink 2.sup.nd module
(looking down)
[0084] FIG. (32) Sketch cross section of heat sink 2.sup.nd module
(looking up)
[0085] FIG. (33) Sketch cross section of heat sink 1.sup.st and
2.sup.nd module (fins and air flow heating)
[0086] FIG. (34) Sketch of water distribution sock arrangement
[0087] FIG. (35) Sketch of cell structure creating hierarchical
system organization
DESCRIPTION FIRST EMBODIMENT
[0088] The first embodiment is on improving the efficiency of the
condensers on air conditioning or refrigeration equipments. This
embodiment in particular is for the upgrade of existing air
conditioning systems.
[0089] The government has mandated through the Department of Energy
a gradual improvement on the required efficiency of new air
conditioning and refrigeration equipment following policies similar
to the gas mileage on cars. Also the Department of Environment and
Protection last January 2010 has prohibited particular refrigerants
for the new manufactured equipments. The usual refrigerants on the
old systems are the R22. The installed base of these old equipments
however are at least 75% of the market for saturated capacity. Thus
if the efficiency of the old equipments is improved by economically
viable process, then the planned policy of energy use for the
nation would be accelerated. The known life expectancy of the air
conditioning and refrigeration equipments are about 20 years.
Therefore statistically, there is a percentage of 9 more years
remaining in the life of these units for availing on efficiency
improvements afforded by this procedure.
[0090] The theoretical ideal efficiency of vapor compression
refrigeration system which are the usual technology used for air
conditioners and refrigeration is the COP or the coefficient of
performance. Under some assumptions, particularly that the
refrigerant operates within its saturated boundaries on the
different phase used for the purpose, the COP is obtained as the
temperature of the evaporator refrigerant (using absolute
temperature units such as Kelvin or Rankin) divided by the
difference in temperature of the condenser refrigerant and the
evaporator refrigerant temperature. Again using ideal conditions,
assuming the condensers and evaporators are considered as infinite
heat sinks or sources, then the refrigerant temperatures are either
the ambient temperature or the control setting for the air
conditioners. This is not the case however because of practical
inefficiency in the heat transfer process for these equipments.
These devices uses the conduction and convection process discussed
above using fins and tubes for the condenser enclosure and surfaces
and electric fan for the air flow. The standard design for air flow
is 400 cubic feet per minutes of airflow for each ton of cooling
capacity for condensers. Therefore for a 3 ton unit and the typical
dimensions for the tubes and fins, one can compute for the
"temperature head" to be approximately 18.5 C for the condenser. I
defined the term "temperature head" to be the difference in the
refrigerant temperature between the heat flow source to the
recipient heat environment. The Department of Energy defines a
standard metric for efficiency for air conditioners and
refrigeration systems. The standard is the SEER or seasonal
electrical energy rating. Since the performance of an air
conditioning system is dependent on the ambient temperature and the
room temperature setting, the SEER metric is specified for ambient
temperature of 85 F and room setting temperature of 82 F. The
standard is computed the same as the COP (under the actual
equipment performance, and not ideal to operating within the
refrigerant saturated region). The SEER could be obtained from the
COP by dividing by 0.29. SEER uses BTU/hr for energy instead of
watts for COP. Assuming that the evaporator coil also has the same
"temperature head", then the total difference on the refrigerants
of the two devices is approximately 37 C. There is approximately
3.5 C temperature head due to the thermal conductivity of the
refrigerant together with the usual implementation of the enclosure
for the conduit for the refrigerant. We may consider approximately
the same for the evaporator. For the sake of discussion, under the
ideal COP computation that the condenser were to use the
vaporization method and result in a "temperature head" reduction of
18 C, this would imply an improvement of 61%. This theoretical unit
would have a COP of 6.73 and reduction of the temperature head of
the condenser by 18 C results with a COP of 10.5.
[0091] The new equipments mandated by DOE for efficiency
performance would have higher SEER ratings. If the vaporization
process were applied to these equipments, the resulting efficiency
improvement would have a larger rate of improvement. This could be
seen by getting the derivative of the theoretical expression for
COP with the condenser temperature head change. The rate of change
is directly proportional to the existing COP or SEER
performance.
[0092] This application is a method by which the efficiency for the
refrigerant heat extraction is improved. The method is applied to
the usual fin and tube type of heat exchange by exposing the heated
fin and tube of the condenser to water to induce the vaporization
and extract the heat from the refrigerant by the usual thermal
conduction and convection using air flow. The vaporization of the
water is enabled by reducing the thermal resistance from the
refrigerant to the receiving medium which is ambient air. The usual
structure of the fin and tube is not changed, but the introduction
of water on these surfaces together with the high temperature of
the refrigerant induces the conduction of heat energy to vaporize
the water on these surfaces. The vaporization of the water is very
efficient heat transfer mechanism. The latent heat of water is 2260
joules if 1 gram of water is vaporized. In comparison the sensible
heat change of the air with the convection and conduction with the
standard process employed with existing equipments provides only
0.001 joules/cubic centimeter/degree celsuis change of the airflow.
The standard fan requirement followed in industry is approximately
400 CFM per ton of cooling capacity. When water is vaporized from
the condenser, the boundary layer consist of water vapor in the
immediate surface area of the fins and tubes that form a similar
boundary layer of heated air as with the usual fins and fans
arrangement. If the boundary layer is maintained to a steady state
allowed by the diffusion mechanism, then the thermal resistant
would increase to the point that the heat transfer is degraded. The
effectiveness of vaporization for cooling capacity improves if the
relative humidity of the air is low together with higher
temperature of the air. The saturation level of water vapor content
of air increases exponentially with temperature. Therefore, for the
same relative humidity (which is the ratio of the water vapor
content of the air to the saturated water vapor content) at a given
temperature, there is more water vapor that could be absorbed by
the airflow at higher ambient temperature. In order to optimize the
design the air flow volume is sustained only up to air saturation.
With the standard fan capacity of condensers, the 400 CFM volume
capacity of the fan is adequate to maintain the total cooling
requirements under all practical ambient temperature the condenser
is allowed to operate.
[0093] The air conditioning and the refrigeration technology had
been implementing the vapor phase change and recovery for cooling
for a long time. The basic components are known and established.
The components of this cooling system are shown in FIG. (13). The
cooling system is a close system where it uses a medium called the
refrigerant that is subjected to changes in its phase as it goes
around the cooling system. The change in phase is implemented by
means of equipments that are designed to enable the flow of energy
as required by the laws of thermodynamics. The phase changes are
such that in suitable sections of the system heat can either be
absorbed or removed from the refrigerant. The equipments involved
are situated in the area being cooled (the evaporator) and the area
where the heat is dumped to the environment (condenser). The
thermodynamic cycle that the refrigerant undergoes is enabled by
introducing some form of energy (in this particular block diagram,
electric compressor) and a metering system. The design and
implementation of the processes by which the phase change of the
refrigerant are factors that determine the efficiency of the
cooling system. Practical constraints on the design stage are
however always a factor.
[0094] This application is for the improvement of the heat transfer
performance of the condenser. Embodiments to apply both to existing
and manufactured new equipments are presented.
[0095] The efficiency metric for the cooling system maybe
understood by examining the thermodynamic cycle of the refrigerant
under an ideal condition where the phase transformation of the
refrigerant is limited to the saturated region. FIG. (14) shows the
phase diagram for the air conditioning refrigerant. The usual
thermodynamic diagram that the refrigerant undergoes can be
presented in a combination of ways. The refrigerant exhibits the
same pressure and temperature and are called the saturated
temperature and pressure of the refrigerant. Therefore, measurement
of either parameter will describe completely the state of the
refrigerant in this saturated phase.
[0096] I have to beg forgiveness for the deviation of the usual way
of presenting the phase diagram. However since in this discussion,
we are concerned about the idea of COP as a function of the
operation within the saturated region, I believe the choice of the
parameters for the phase diagram shown would make the migration to
the practical system more understandable. The phase diagram is
shown as temperature versus enthalpy. The usual choices are
pressure against enthalpy, and temperature against entropy.
[0097] On the left of the phase diagram is the boundary of liquid
and mixed state (liquid and vapor coexist) for the refrigerant. On
the right is the boundary of changing from the mixed liquid and
vapor (saturated region) to a completely vapor phase. The
independent (horizontal axis) variable is shown as the energy
content of the refrigerant per gram that flows through the
evaporator or condenser devices. The energy increase or decrease of
the refrigerant as it traverses along the cycle is indicated by the
enthalpy H. The enthalpy change H is dependent on the entropy S of
the refrigerant. The entropy changes with the corresponding changes
in energy flow in or out of the refrigerant. The enthalpy change is
manifested as the temperature (absolute) T multiplied by the change
in entropy along the cycle. The accumulation of the changes in
energy content of the refrigerant are shown at the indicated
transition points as the resulting energy per gram of refrigerant.
During the phase change within the saturation region, both the
temperature and the pressure are constant, e.g. from (1,2) to
(2,3). Since the temperature is constant, the changes in enthalpy
are all related to the absolute temperature and the effective
change in entropy. Outside of the saturated region of operation the
temperature and pressure change with corresponding changes in
entropy. One can see now why it is a rational strategy to assume
operation of the vapor compression recovery system to occur only
for purposes of deciding strategies for efficiency improvement with
the understanding that this region of operation contributes to most
of the energy involved with the metric of efficiency.
[0098] The mechanical losses with the movement of the refrigerant
through the tubes could amount to a significant loss in energy and
thus efficiency. For example if the pressure drop through the
evaporator results in a saturated temperature change of 3 C, this
is approximately 1 percent on the cooling capacity of the
evaporator. Other factors are ignored. For example the mixed
presence of liquid and vapor in the tubes creates mechanical states
of blobs of empty spaces or sections of completely liquid
refrigerant or vapor along the tube. Another are the losses in the
throttling process where some of the energy during the
transformation from the liquid output of the condenser to the lower
temperature results in a phenomena called flashing where vapor is
created with the throttling process resulting in loss of energy.
Suffice it to say that it is mentioned here but the impact of their
contributions to the losses are ignored.
[0099] The solid line depicts the boundaries by which the phase of
the refrigerants changes to being completely liquid or vapor to a
combination of liquid and vapor when the refrigerants acquires
heat. The right side of the phase diagram shows the boundary by
which the refrigerant phase changes from the saturated phase
(combination of liquid and vapor) to a completely vapor state. This
is the region as shown in FIG. 2 with labels (1,8) to (2,3) and
also ((4,5) and (6,7). The points indicated from 1 to 8 marks where
the different cycles of the refrigeration cycle change. (1) and (8)
is when the refrigerant enters the evaporator where warm air energy
from the room is extracted by the refrigerant. The regions between
(4,5) and (6,7) is the condenser where the energy extracted from
the evaporator is rejected from the system to the outside
environment. Thus the refrigeration system extracts heat from the
room and dumps it out to the environment. When the air conditioning
or refrigerant system operates entirely within the saturated
region, the resulting COP or coefficient of performance of the
system provides the metric a's the ideal limit of the efficiency of
the system for the phase operation the refrigerant. The COP is a
measure of how much energy is needed to change the thermodynamic
phase of the refrigerant to function from absorbing heat energy and
rejecting heat energy from its' mass. The COP is the amount of
energy needed to convert the refrigerant from (1) to (2) for the
mass refrigerant flow divided by the energy needed for the
compressor to change the vapor refrigerant from a low temperature
saturated phase (2) to a high temperature saturated phase (4). The
change in energy in the process of either extracting heat from the
room or eliminating the energy from the refrigerant is shown in the
horizontal axis as enthalpy. For example as the evaporator
refrigerant absorbs heat from the room, it's enthalpy increases
from (1) to (2). Since the temperature and pressure of the
refrigerant remain constant within the saturated region, then we
can say that the COP maybe expressed in terms of the temperatures.
This formula is directly dependent on the low side temperature
(evaporator) of the system and inversely proportional to the
difference in the temperature between the high side (4,5) to (6,7)
(condenser) and the low side (8,1) to (2,3) (evaporator) saturated
refrigerant temperature. The temperature should be consistently in
absolute Rankin or Kelvin units. The low side temperature of the
refrigerant is dictated by the setting desired for the system. For
an air conditioning system, this would be a temperature for human
comfort. For a refrigeration system this would be dependent on the
purpose for the refrigeration. For a freezer, the low temperature
would be below freezing temperature of water. Thus, the theoretical
limit of performance for this particular cooling system is bounded
by the two temperature requirements, namely product usage and the
ambient temperature. If the condenser and evaporator are infinitely
efficient in heat transfer, then the area of concern would be its
minimum. This means that the denominator on the COP formula is
reduced and would result in a higher COP. The high side refrigerant
would be close to the ambient temperature, and the evaporator low
side refrigerant temperature would be close to the control room
temperature. In reality, the ideal infinite heat transfer is not
achieved because of the thermal resistance in conveying the heat
flux from the refrigerant as required for the function of the
evaporator or condenser. I will use the term "temperature head" as
a metric for the magnitude of the average thermal resistance of the
evaporator or the condenser with respect to either ambient
temperature or the room control temperature. The "temperature head"
is the difference between the condenser and evaporator ambient and
room temperature and the corresponding refrigerant saturated
temperatures. The temperature head are determined by the physical
implementation for each of the units. There are other losses that
adds to inefficiency in the implementation of a physical system.
These are superheating, sub cooling, flashing, mechanical losses,
hydraulic losses on the plumbing and electrical efficiency losses
on the motors for the compressors and fans. FIG. (15) shows all
these other thermodynamic processes involved with a practical
refrigeration or air conditioning system.
[0100] The COP metric disregards all these factors but serves as a
guide to achieve higher efficiency for the cooling system. The term
superheating results from requiring practical air conditioning
systems to have adequate assurance that the refrigerant to the
compressor at the suction line are all in vapor phase. Otherwise
the compressor could be ruined. The term sub cooling is similar to
superheating except it is the degree by which the refrigerant from
the condenser is cooled lower than the saturated temperature of the
refrigerant. Flashing is when the energy of the liquid during
throttling converts some to vapor with the attendant loss in
energy. We neglect inefficiency on energy based on the relative
total energy contributions compared to the thermodynamic processes
within the saturated regions.
[0101] Note for trivia that under the specifications of the ambient
temperature and control temperature set for the definition of SEER,
the corresponding COP under ideal condition of infinitely capable
heat sinks and heat source for the evaporator and condenser
respectively that the COP is 180 with a corresponding SEER of 622.
It is a very far target to achieve but hopefully could serve as
encouragement that indicates there is a lot of room for improvement
over the horizon.
[0102] FIG. (13) shows the transition points where the VCRS process
within the close loop cycle. FIG. (13) transition points pairs to
indicate that are practical necessities for an actual unit where
further processes have to be implemented. The sequence of the
transition follows an increasing order with the system cycle
following a counterclockwise direction. Point (1) is when the
refrigerant enters the evaporator as a combination of liquid and
vapor after undergoing "throttling" where the refrigerant pressure
is changed from the high saturated pressure (8) to the lower
saturated pressure and temperature (1). This refrigerant phase
enables the extraction of heat from the room because the saturated
temperature of the refrigerant is lower than the room temperature
setting. When the heat from the room is extracted in reaching (2),
the refrigerant undergoes mechanical work. This transition point in
FIG. (10) also shows transition (3). This is to show that in an
actual cooling system, it is mandatory to operate the cooling
system such that there is assurance that the refrigerant is
completely in the vapor phase before undergoing mechanical work by
the compressor. Otherwise, the presence of liquid in the
refrigerant could ruin the compressor. From (3), the compressor
changes the pressure and temperature of the refrigerant by
introducing work. This raises the temperature and pressure of the
refrigerant to (4,5) in FIG. (14). Transition point (4) is the
state of the refrigerant after the compressor. FIG. (15) shows the
full phase change cycle for the refrigerant for an actual system
tested with R22 refrigerant. The compression of the refrigerant is
not in the saturated region (4,5) to (6,7) because of the reason on
maintaining complete vapor on the input to the compressor. FIG.
(13) disregards this in order to simplify the explanation on how to
achieve thermodynamic efficiency. Cooling of the refrigerant brings
it to the saturated region (5). The transition regions (4,5) to
(6,7) is when the condenser rejects it's heat content to the
ambient environment. Therefore the energy used for cooling the room
would be the changed in the enthalpy (horizontal axis) from
transition point (1) to transition point (3). The condenser on the
other hand removes the energy corresponding to the difference in
enthalpy at transition point (4) to transition point (8). The work
provided by the compressor would be the enthalpy change from
transition point (3) to (4). Examination of the phase diagram FIG.
2 shows that the magnitude of the change in enthalpy over the
regions where the refrigerant is in the saturated region is much
larger than the region where the work involved in achieving the
change in phase of the refrigerant by the compressor. The other
losses such as pressure drop loss on the tubing for the evaporator
and condenser affects the thermodynamic efficiency in a significant
manner because the horizontal track (1,2) in the evaporator and the
horizontal track ((5,6) drops from being horizontal. The effect is
to reduce the average effectiveness of the saturated temperature of
the refrigerant
[0103] FIG. (15) shows the phase diagram that an actual air
conditioning system undergoes. The FIG. (16) in a similar fashion
as FIG. (14) are shown to scale such that the magnitude of the
energy of the refrigerant is indicated graphically. The saturated
regions (1,2) and (5,6) have energy changes relatively larger than
the energy changes on the refrigerants during (2,3), (3,4) and
(4,5) and (6,7). The region (2,3) is to assure that the refrigerant
enters the compressor to be completely vapor. This is termed
"superheating" at the suction line. (3,4) is the compression cycle
of the refrigerant. The resulting phase at (4) is both a result of
the superheating and also the compression process. The region (4,5)
cools the refrigerant to bring it to the saturated region. Note
that at the states (4,5) and (2,3) the saturated pressure of the
refrigerants are maintained to be almost the same as the saturated
temperatures at (1) and (4). At (5), the refrigerant is completely
liquid. When the condenser has more cooling capability, then the
liquid refrigerant is cooled to (7) with the pressure still
maintain as from transition point (4) to (7). This region is called
the sub cooling of the refrigerant. This is desired similar to
super heating the throttling process for a more desirable liquid
state of the refrigerant before throttling. From FIG. 17, which is
an actual phase diagram of an air conditioning system using R22,
one can see that the amount of energy involved within the saturated
regions are much larger than the other phases of the refrigeration
cycle. All the figures shown from FIG. (13) were drawn to scale
such that the image seen would show the relative magnitudes of the
energy changes through the different transition points.
[0104] FIG. (14) through FIG. (18) are all drawn to scale as a
result of analysis using the R22 refrigerant. One may verify for
example in FIG. (14) that the ideal COP definition is satisfied
under the condition that the refrigerant operates within the
saturated boundaries of the phase diagram.
[0105] The reduction of the "temperature head" on the condenser is
addressed. Particular application is on the process of upgrading
older installed air conditioning systems which have efficiencies
that are much lower than the requirements for system efficiency for
new equipments as mandated by the Department of Energy.
[0106] This application uses the vaporization of water as a vehicle
to conduct the heat flux from the refrigerant in the condenser to
the ambient environment to improve the cooling performance and
capacity of the condenser.
[0107] The process consist of--(1) water delivery metering (2) air
flow volume rate control (3) air flow temperature and humidity
conditioning. These processes results in improvement in efficiency
over a wider range of temperature and relative humidity. Also the
effect of scaling buildup is reduced with predictable maintenance
requirements.
[0108] The vaporization process occurs at any temperature. It is
the result of the equilibrium between the high energy molecules
from the liquid balanced by an equal amount of vapor molecules
losing energy and changing back to liquid. When the enclosure does
not loss any of the material water vapor, then the equilibrium
state is called the saturation level at that given temperature. The
saturation level is exponentially related to temperature. The
saturation level implies that it creates a vapor pressure because
of the high concentration of water vapor. The vapor pressure is
dependent on the temperature. Diffusion therefore starts together
with a negligible amount of sensible temperature change
perpendicular and away from the water film. Diffusion creates a
water vapor profile and temperature profile toward the steady state
where the whole chamber would acquire saturated conditions After
this, the heat flux flow stops. An upper limit on the gradient of
the vapor boundary layer is dependent on the saturated water vapor
content as it traverses away from the water film surface. Thus
theoretically, the temperature of the water film could be made to
be close to the ambient environment. The temperature gradient could
be made very sharp by ensuring that the vapor pressure from the
surface of the water film is as high as possible. This would be
adequate if the air flow can effectively keep up with the
generation of water vapor and establish a very sharp gradient for
diffusion. The process of air carrying the water vapor is the
mechanism that enables this. As a best case scenario, for example
under the condition that the air flow is adequate in removing the
water vapor created by the vaporization, that the thermal
resistance for the heat flow from the refrigerant energy is limited
by the refrigerant and the water film effective thermal
conductivity. The thermal conductivity of the copper or metal tube
is so much greater than the refrigerant or the water film.
[0109] The following factors are design parameters for the
effective application of vaporization for the upgrade. The first is
to meter the delivery of water to the fins and fans such that the
needed amount for the vaporization contribution is maintained. This
improves the use of water for the cooling process. Also careful
metering of the amount of water minimizes the thickness of the
water film on the surface of the fins and tubes. Thus the
contribution of the water film to the total thermal resistance from
the refrigerant to the ambient environment is minimized. This is
particularly clear because the thermal conductivity of water is
very close to the refrigerant. The second is to maintain the
minimum thermal resistance presented by the boundary layer by
controlling the air flow. The metric for this is the difference in
temperature from the ambient air and the exhaust air from the
condenser. In the case of the cooling that is applied using the
sensible heat transfer of the airflow, the change in temperature is
proportional to the heat energy extracted per unit time for a fixed
topological cooling structure. With the combination of the two heat
transfer processes, the latent heat of vaporization mechanism tends
to decrease this differential in proportion to the percentage of
cooling attributed to sensible heat transfer. If the latent heat of
vaporization of water were to be optimized, the cooling effect
would reduce the sensible temperature change. Thus the difference
in inlet and outlet air flow temperature is used as a feedback
control for the efficiency in the delivery of the optimum amount of
water. The limits would be dependent on the relative humidity of
the ambient air since the amount of water vapor that can be
generated from the heat transfer would be limited theoretically by
the saturated air. The normal temperature range of humidity and the
temperature operation for existing equipments however have SOP
equipment performance that saturation is not reached. The second
metric is to have a strategy of maintaining the cooling efficiency
of vaporization by maintaining the high conductivity of the
interface between the fins and tubes to the ambient air. This is
maintained by minimizing the water vapor boundary layer thickness
and also the conductivity between the refrigerant to the immediate
surface of the boundary layer. The boundary layer explanation is a
catch all explanation of why air flow is needed. The control of the
air flow is needed to avoid getting close to the boundary of
saturation for the outlet air. The control of these parameters has
to be combined and coordinated with the water delivery system.
Analysis applying the assumption that laminar flow occurs on the
installed AC fin and tube condensers shows the validity of the
adequacy of the fan installed in these equipments that are
candidates for upgrade. The standard operational design for these
condensers has been 400 CFM per ton of AC capacity.
[0110] The use of water always presents practical problems of
scaling. The scaling problems are addressed knowing the following
information about their formation and development. The PH factor is
an indication of the possible magnitude of the potential of the
problem. A more acidic water would minimize the probability. The
interface to the water film where the amount of carbonate material
that would potentially develop to scaling is contained by
minimizing the volume of the water involved. The amount of
carbonates that end up deposited on the metal surfaces are
predictable. This is because the metering process of the water
achieves the total vaporization of the delivered water and all the
carbonates are precipitated and deposited on the surfaces. The
amount of deposit would be dependent on the hardness of the water
and the total accumulated cooling energy. The metering of water for
vaporization optimizes the use of water and extend the time for
which maintenance due to formation of scaling would be needed. The
maintenance could be divided into two segments. The first segment
is the actual delivery equipment to the fins and tube of the
condenser. The second segment would be the scaling on the fins and
tubes themselves. The latter would lend to mechanical cleaning
since in most cases access to the fins and tubes are available
because of the inherent topology of the present condensing devices.
Thus mechanical cleaning with high volume and low pressure cleaning
water, is a convenient and economical process. The water delivery
material is selected for high contact angle which is a measure of
the adhesive property of water to the surface. Maximizing the
contact angle for the material would reduce the formation of
scaling on the material.
[0111] The water delivery system is designed such that the metered
and controlled manner of delivery of the water shall be distributed
evenly on the fins and fans. This would help extend the time
necessary for maintenance because it avoids the localization of
water distribution flow which accelerates the build up on these
local regions. Also it is known that the scaling that forms has the
property that the adhesion develops stronger after a certain
threshold of time and from that point on accelerates the build up
and formation on this initial scaling to aggravate the conductivity
of the device. This property however might be very dependent on the
action of bio film buildup and would have minimal impact. This is
true when the amount of water is sufficient that bio film maintain
on the heated surfaces. This development of bio film accelerates
the scale buildup due to carbonates. Therefore the strategy is to
allow periodically a mechanical cleaning of the surfaces of the
water delivery. It is proposed to flood the water delivery from
another vessel and then while it is flooded subject the container
to mechanical pressure forces in terms of ultrasonic frequency that
would be designed such that the spectrum scans the possible
resonance of the initial scaling particles formed. This can be
easily done by both the frequency change on the ultrasonic signal
and also varying the resulting harmonics with the waveform of the
signal such that the natural resonance of the particles are
achieved with very good certainty. This procedure is well known in
testing electronic devices for electromagnetic compatibility issues
and performance. Since the timing logistic is designed to be done
during the initial formation of the scaling, the mass of the
particles would be low and therefore the resonance of the particle
is high and could be amenable to ultrasonic pressure waves. After a
dwell time of mechanical cleaning, a flushing with large amount of
water would be used to carry out the particles removed from the
walls of the delivery system. The duration for the mechanical
ultrasonic cleaning is extended with occasional use of chemical
cleaning in terms of reducing the PH of the water solution.
Analysis was made on the assumption that with controlled metering
of the delivered water, the water with known hardness would deposit
all the carbonates it carries with it because of total
vaporization. The maintenance of the scale buildup maybe guided by
an empirical test with results that determines the time threshold
by which maintenance for the heat transfer surfaces have to be
implemented because of undue degradation of the heat transfer
property. The test data from the literature and the predictability
on the magnitude of the scale buildup because of the metering
process of water delivery predicts a result that it would take a
year to degrade the thermal conductivity of the system using water
vaporization.
[0112] The general idea on how to implement the delivery of water
for vaporization with consideration on minimizing water usage,
scaling, maintenance and initial capitalization is addressed. There
are two possible implementations for the existing fin and tube
condenser structure.
[0113] FIG. (19) shows schematic of the metered water delivery. The
schematic consist of a dual tank 196 and 198 which are respectively
the source tank from the water utility 190 and the pressure
controlled tank 198. The water source tank is controlled by a float
switch that regulates the water coming from the utility. 200 is a
small peristaltic pump able to be driven in a bidirectional manner
such that the water delivery is capable of increasing or decreasing
the pressure head. 222 is the peristaltic tube port for the water
delivery pressure tank, and 224 is the peristaltic tube port for
the source tank. 226 is the port outlet for the pressure tank 198
where the water delivery to the tray 204 can be closed with
electric solenoid 202. The utility water comes in through a float
and valve arrangement 192 and 194 to maintain automatically
sufficient water supply from the utility line.
[0114] The water delivery control is shown. 210 shows the
temperature sensor made of thin wire of controlled length. 210 is
shown with the wire grid arranged so that the sensor is exposed to
the whole air flow area and automatically sense the average
temperature. For example in the diagram the wire is wound
sequentially 1, 2, 3, 4, . . . , 8, 9, 10. The block diagram and
schematic of the water delivery sensing and control consist of the
condenser fin and tube arrangement 208 and the water delivery tray
204 and peg arrangement 206 and the temperature sensors 210 and
212. Precisely equal current sources 214 and 216 for each of the
temperature sensors 212 and 210 generates a voltage proportional to
the temperature measured by each sensor. The difference in the
voltage which is a measure of the degree of sensible temperature
rise of the air flow is measured and amplified by 218. 220 receives
the output of 218 and generates the power signal to control the
flow of water in the dual tank which is connected to the water
supply. Transfer of water from one chamber or the other is
controlled by a simple peristaltic pump that could transfer water
either direction for the purpose of maintaining a water head at the
chamber for the water metering. The head of the water in this
chamber creates the flow rate needed for the metering of the water
for vaporization. FIG. (19) shows the structure of the dual
chambers. The tank has to be situated above the water delivery
nozzles to establish the necessary hydraulic head H. Delivery to
the nozzle equipments shall be with small tubing either metal or
plastic.
[0115] FIG. (20) and FIG. (20a) are the details on the structure of
the water delivery tray and the uniform distribution pegs for the
water droplets. 204 is the water distribution tray. The water from
the pressure tank 198 comes into the tray through a entry port 244
where a layer of water film forms above nozzles 240. These nozzles
are uniformly spaced on the tray. The water pressure head generated
in the water pressure tank provides the necessary head to maintain
a frequency of droplet formation. The nozzle diameter determines
the size of the droplets. FIG. (20a) shows the elevation of the
structure to emphasize the regularity and the arrangement for the
pegs with relation to the nozzle locations.
[0116] FIG. (20) shows one implementation of the water delivery
trays. The trays would be installed above the condenser fins so
that the metered water shall fall uniformly under the condenser
coil axis. Upgrades shall be custom activities and this might
involve cutting a slot opening on the plate covering and protecting
the original condenser enclosure. The tray material shall be
selected such that it has high contact angle to hinder the
formation of scales on the nozzles. The nozzle are uniformly
separated with nozzle diameter selected such that metered water
delivery is in the form of droplets.
[0117] It is everyone's observation after a medium rain on a loose
or even firm soil that veins of channels are formed because of
preferred paths for the water flow. A similar occurrence could
happen when there is sufficient water volume for flow. The
propensity for such phenomena is preempted by using the second
section for the water delivery. When the veins are formed on the
condenser structure, the thermal efficiency of the process is
degraded. The second structure 206 below the tray is a series of
pegs that again are selected to be of a material that has high
contact angle. The uniform location of the nozzles and the opening
of the orifice determines the spacing of the pegs. When water
droplets from the nozzle falls, the water drop forms spherical
shape because of the high water surface tension. The peg location
is such that the droplets formed on the tray falls on the pegs. The
high contact angle on the pegs causes the droplet to roll to either
side of the peg. The next peg is located such that the falling
droplet will again encounter the next peg falling with uniform
probability to either side of the upper peg. Subsequent layers of
pegs therefore will distribute statistically the distribution of
the water film to the condenser fins and tubes and avoid or slow
down the formation of veins. The metering of droplets formed is
controlled by the peristaltic pump that transfers water from one
chamber of the tank to the other.
[0118] The effective implementation of the water metering delivery
would alleviate the maintenance of the condenser fins and tubes for
scaling buildup. The probability of bio film formation is reduced
because of the limited presence of liquid water with the metering
system. Also the carbonates that the water delivering system
carries would be predictable when water hardness are known.
Therefore the maintenance and logistics on when it is done is
predictable. Extrapolation from empherical test data by others on
condensers showed that under conditions of the worse case hardness
of water source, the maintenance for scaling buildup would be
needed in about one year. The empherical testing was done under
conditions favorable for bio film buildup. Thus the interval stated
is conservative and the maintenance frequency is practical and
affordable. The maintenance for removal of the scaling is improved
such that high volume and low pressure water cleaning is adequate.
This is because the bio film formation is avoided as much as
possible with the water metering process. Otherwise it would
require more often maintenance using complicated maintenance
equipment. Empherical test showed that under the formation of bio
film, the threshold where the adhesive property of the bio film is
accelerated occurs approximately 2 months. The conditions by which
this result was obtained are avoided in this process.
[0119] The theoretical COP improves with decreasing ambient
temperature, assuming the "temperature head" of the condenser does
not change. However when higher cooling capacity is needed, the low
ambient temperature limits the available water vapor from the low
temperature air. Under this situation the air flow control would
demand more air volume. With the upgrade on the systems, this
convenience for adjustment is not available.
[0120] The vaporization process has the advantage assuming there is
adequate room to support water vapor formation for the cooling
load. The capability of the air conditioning or refrigeration
systems on low ambient temperature is degraded especially with
large cooling systems because of the magnitude of the saturated
humidity at the low temperature.
[0121] This limitation is alleviated if the air flow is raised to a
higher temperature than the low ambient temperature to increase the
available water vapor content for vaporization. The procedure is to
configure sections of the condenser to operate normally using the
sensible heat air transport for convection. From FIG. (12a) and
FIG. (12b) one can see that heating and/or cooling first but with
the air flow temperature adjusted to a higher temperature, the
capacity of the system is increased.
[0122] The upgrade is implemented as follows. The block diagram of
the upgrade for a central air conditioner condenser or
refrigeration system is shown in FIG. (23a). The existing condenser
is conveniently divided into three (3) sections by suitable
baffling arrangement. Each of the three sections 210, 212, 214 are
equipped with the water delivery system for vaporizations. These
are shown as 206a, 206a and 204b, 206b and 204c, 206c. A section is
designated as the section that would make use of vaporization for
cooling. Each of the sections have the water delivery valve 114a,
114b, 114c such that the system can be operated using fully
vaporization. Section (210, 204a, 206a, 114a) is mechanically
baffled to operate under vaporization when there is an inadequate
vapor capability because of the ambient environmental conditions.
The condenser air flow from the fan has the baffle arrangement such
that a portion is routed to section A. When sections of the whole
condenser is denied of water delivery by controlling 114b, 114c
then the fan output air flow would exhaust warmer temperature than
the incoming ambient air. A portion of the warmer air is routed via
the baffle arrangement to section a. The warmer air would allow the
condenser section to have a larger cooling capacity using
vaporization because of the added water vapor cooling capacity.
[0123] The benefits in the reduction of the head discussed before
is compromised to the level where the needed cooling capacity for
the equipment is reached. Still the vaporization augments the
original air material convection for the condenser.
[0124] If one were again to allow the application of the
vaporization technique to another remaining and trailing section of
the condenser, this will achieve the sub cooling which improves the
capacity further.
[0125] Notice that FIG. (22) has an implied configuration where
vaporization technique is applied to the whole condenser equipment.
Thus we could eliminate the individual valve controllers and leave
only one at the most.
[0126] FIG. (22) is the embodiment for an upgrade where total water
delivery is made on the full condenser fin and tube arrangements.
210 are the average temperature sensors, 204a, 206a, 204b, 206b,
204c, 206c are the water delivery tray and peg structures. 220 is
the opening for the condenser fan air flow.
[0127] FIG. (22) is modified such that the various valves needed
for individual section control on water delivery is added as shown
in block diagram FIG. (21) FIG. (23) shows the implementation which
is the same as FIG. (22) except the shroud of baffle 230 is
installed. The side panels of 230 indicated as 232 could be removed
so that full vaporization operation can be implemented.
[0128] The tradeoff of a compromise on the resulting efficiency and
the noise from the fan air flow volume is a tradeoff decision that
comes into the picture. The full potential of reduction of the
temperature head in the condenser with the use of latent heat of
vaporization may be compromised. When there is a need to warm up
the air for the vaporization process, the procedure would lead to a
higher "temperature head" than when we have complete latent heat of
vaporization applied. The preconditioned air then is used for the
latent of vaporization heat exchanger that would have the remaining
cooling capacity to maintain that effective temperature head. This
will be a dynamic parameter that will be dependent on the ambient
temperature, humidity and cooling load. This increased temperature
of the air would lead to a demand for lower air flow for the heat
exchanger using the latent heat of vaporization. Since the latent
heat of vaporization does not involve increase of sensible heat and
that the preconditioned air is exhausted to the environment, the
condenser could be installed indoors where the operating conditions
are controlled and would lead to simpler control and uniform
performance. The desired resulting efficiency for the system can be
weighed with the benefits of a smaller unit because of the lower
air flow. This implies a physically smaller refrigerant enclosure
would be required. The smaller size enables users to enjoy the
configuration of having the system indoors. The ramifications of
indoor locations are discussed in the third embodiment
[0129] FIG. (24) shows a schematic of the upgrade where full
flexibility in selecting sections of the condenser could be made to
operate on vaporization. It is similar to FIG. (22) except the
addition of the electronic controller for valve and motor control.
It is used also for the temperature sensor to determine the
effectiveness and control of the vaporization procedure. The water
delivery trays will have controllable valves from the water
delivery tank system. These are the valves 114a, 114b, 114c. Water
delivery control and selection of condenser sections to operate on
sensible or latent convection is implemented with the controller
240.
[0130] With the larger capability for cooling to the point that the
air conditioner can be cooled to sub cooling region, the efficiency
of the vaporization process for the air conditioning is more
capable of providing improve efficiency in these situations where
the cooling is needed. In situations such as refrigeration systems
the equipment has to operate on lower ambient temperatures than
usually required for air conditioners, The lower temperature limits
the available room for the same volume of air to absorb the cooling
capacity needed from the vaporization process to accommodate larger
cooling load. This is because of the lower saturated humidity at
the lower temperature.
[0131] FIG. (24) shows the block diagram of the routing of the air
flow by means of physical means such that the problem stated is
alleviated. The problem at the lower ambient temperature could be
alleviated with a compromise on the theoretical limit of achieving
the full capacity of efficiency that could be obtained from the
vaporization process This would be in between the ambient
temperature and the "temperature head" addition to the original
equipment. The block diagram shows a portion of the incoming air
flow to be operating in the normal sensible temperature cooling
process that generates an increase in the temperature of the
incoming air. Since no vaporization process occurs here, the
relative humidity of the outgoing air from this portion of the
condenser is much lower than the incoming air. The increase in
temperature of the outgoing air opens more cooling capability from
vaporization process. A compromise on the magnitude of the
temperature rise available with the SOP "temperature head" of 18.5
C is possible leading to increase efficiency and performance for
the refrigeration than is afforded by the original configuration.
The pre heated air flow for vaporization is used for the
vaporization cooling process in another section of the overall
condenser cooling arrangement. The output from this section is then
routed out and mixed with the output of the first evaporator
operating in the sensible temperature region of the air flow. The
idea can be extended such that the water delivery is divided into
three sections. The delivery system water metering control shall
have the capability of operating all of the sections on
vaporization. The first and the third sections could be turned on
and off. Operation of mixing both sensible temperature operation
and full vaporization cooling process could be achieved with an
overall higher system efficiency extended to a wider range of
ambient temperature and humidity conditions. FIG. (26) through FIG.
(28) inclusive are sketches of the implementation for upgrade using
this process. The block diagram for the electronics control needed
is shown in FIG. (29).
[0132] The equipment with the preheating chambers are shown in FIG.
(26) through FIG. (29). The flexibility afforded by the scheme of
three condenser sections with the associated valves for water
delivery is possible only if an embedded controller were designed
and implemented for system input parameter measurements and
control.
[0133] The technology use on the equipments for upgrade has the
inherent reduction in efficiency with increase temperature and
humidity. It is at these situations where the efficiency
performance is important because of the high usage.
[0134] Another method for water delivery is the use of spray
nozzles suitably located to effect a uniform distribution of water
spray. It is shown in FIG. (30). It is a more expensive procedure
with the high pressure needed and pump to for the pressure tank and
associated valves. It is of course a very practical option that is
a mature process.
[0135] The upgrade process is inherently limited in scope. Since an
air conditioning or refrigeration system is designed with all
components considered, upgrading the performance of an equipment
comprising the system will not necessarily result in the
achievement of the objective. This is particularly true in the
upgrade when the compressor is not a viable component to replace.
The compressor is designed with the evaporator characteristics and
the condenser in consideration. Improving the theoretical COP with
vaporization process is one of the items that have to be modified.
Since the compressor physical characteristics are not changed,
there is a need for other control devices or strategies in order to
accommodate the improvement in the cooling efficiency of the
condenser for upgrades. The details on this will be presented as
another separate application. Actual tests have been made to verify
that the procedure as a companion for the usual hysteretic control
on residential and small air conditioning systems had been
verified.
Description Second Embodiment
[0136] The second embodiment is the application on cooling computer
chips. The fabrication of computer chips and associated digital
devices had been following Moore's law of speed and density. At the
present, computer chips are dissipating over 100 watts. The
fabrication of silicon devices have developed to the point that the
limiting factor is the dissipation of the heat produced in the
silicon chip. The reliability of any electronic is dependent on the
operating temperature margin from maximum temperature that the
solid state devices operate in. The devices are rated from 125 C to
at least 150 C depending on the technology used. The feature size
(relative size of the basic transistor cell) has been reduced
considerably by several orders of magnitude. The technology is that
a system on a chip is the desired topology. With this the CPU,
memory, dedicated hardware computation algorithm components such as
DSPs, and other system functions that make use of the wide CPU bus
are desired for processing efficiency to be integrated into a chip.
This architecture is beneficial in that the bottleneck of access to
the other devices are not slowed down by any parasitic that are
natural when they are mounted on the PC board. The projection is
that if this were done, the power dissipation of such devices could
reach a power density of 1000 watts per square centimeter. The
cooling towers that are presently used in desktops are heat pipes
where the thermal conductivity is maximized from the chip to the
heat sink. The heat sinks physical size using this technology
together with the implementation of convective air flow are larger
than 100 cubic inch in volume. The fan speed generate approximately
2.5 meters per second velocity for the air flow.
[0137] The process is applied to computer chip cooling enabling
smaller than the 100 cubic inch volume to cool the projected 1000
watts per square centimeter power density. FIG. (25) through FIG.
(34) is an implementation following the procedure discussed
above.
[0138] The embodiment is such that practical considerations are
included. The invention does not preclude other means but the basic
idea of applying the maintenance of good thermal conductivity path
with suitable presentation of water for the vaporization
process.
[0139] There is a base 260 such that when the heat sink module is
installed would be mounted to the computer chip. FIG. (26) is an
elevation and top view of the heat sink. It would be mandated that
the material which in all probability is metal should have the
highest thermal conductivity allowed with practical economic
constraints applied. It consist of three pieces. 260 is the bottom
block. It has mounting means such that it could be mounted with the
computer chip. The mounting for the block is shown such that the
heat sink orientation is vertical with the other configurations
that the PC board might be oriented. That is there is mounting
provision on the bottom of the block and the side of the block 264.
This block shall have the precautions needed before such that the
air gaps that are present in the interface between the computer
chip package and this block are minimized with thermal compound
application. This block is configured such that the other part of
the module could be detached easily for either maintenance or
replacement. This is necessary because of the scaling problem that
is inherent with the process. Strategies for the design of the heat
sink for maintenance and reliability. Also the second block 262
attachment is designed for ease of replacement or maintenance.
Block 262 has the chamber where the vaporization occurs.
[0140] 264 consist of a port for input for air flow. The heat sink
has the capability of having the temperature higher than ambient
because of the high temperature tolerance of the silicon computer
chip. The cooling process therefore is to initially warm the
incoming air. The high conductivity block 264 has a labyrinth of
air passages as indicated in cross section view FIG. (28), FIG.
(29), FIG. (30), FIG. (31) and FIG. (32). The air flow temperature
is raised during its passage through these labyrinth of holes. It
is not shown in the figures that there is an associated air flow
pump externally that pushes the air for the required air flow. This
control is provided by an external embedded controller. The
temperature sensor that is needed to maintain the metering of the
water are 266a and 266b. The sensors are designed in a similar
manner as previously discussed in the air conditioner systems. An
averaging feature is designed in. The circuit is similar for
converting the temperature differences to control the water
delivery system 260 block has an input port 270 for the ambient
air. FIG. (28) shows the bottom of the labyrinth of holes. There
are chambers that serve as conduit for the incoming air to the
holes running vertically on the block. Similar network of chambers
acts to receive the air flow on top of the block. It is exhausted
to the bottom of block 262 and serves as the conditioned air flow
for the vaporization. FIG. (31) is a view looking towards the
interface to block 260. 310 shows the need for effective seal at
the interface between block 260 and 262 to avoid any air leaks When
the input air is warmed up, the capacity for cooling increases
because of the larger amount of water vapor air can support. It is
also beneficial in another way in that the volume of air needed to
carry the transport material of water vapor is less.
[0141] 262 as shown in FIG. 33 contains regularly spaced fins to
convey the heat flux to the water film for vaporization. The
effectiveness of the vaporization is obtained by controlling the
air flow velocity or volume and temperature. Temperature sensors
266a and 266b when driven by equal and constant current sources
would have voltage differences proportional to the difference in
temperature. The effective circuit is similar to what was
implemented for the air conditioning condensers. The two
temperature sensors are mounted on 268 which is a detachable side
cover for 262.
[0142] FIG. 34 shows details on the water delivery to the fins. The
delivery consist of a sewn fabric 352 and 350 embedded tubes
capable of withstanding the temperature of the fins. The fabric has
to have the property of porosity. For example a possible candidate
is the name brand GORE TEX commonly used in garments and
sportswear. The fabric has a vaporization is close to the
vegetation transpiration rate. The fabric is sewn with the tubing
such that it would form a system of socks that would hug and
enclose the metal heat fins. Stitching holes have to be sealed.
There would be some structure 354 to help ease the installation for
repair or manufacturing. 356 and 358 serve as drain for water as a
preventive measure. 356 is a trough at the bottom of the fins that
has natural slope for water drain. The delivery of the water to the
water sock network is on a port also on the detachable cover 268.
The air flow exhaust port is 320 and the water delivery entry port
is 322. Also shown is 324 as the connections for the temperature
sensors. The drain channel 358 may or may need a drain exhaust but
if there is high reliability on the water delivery control, then a
liquid water sensor detector would be enough. Another alternative
would be to have desiccant capable of absorbing non vaporized water
to be temporarily absorbed and then become part of the vaporization
process.
[0143] There would be situations where smaller volumes and possibly
higher cooling capacity requirements would be needed. The volume of
the heat sink can be reduced if the vaporization rate that is
required by the heat flux is supported physically by the surface
for the diffusion. Together with this is the rate of transport
provided by the air flow. The diffusion gradient can be optimized
by the temperature of the air flow to provide a larger difference
in the vapor pressure from the vaporization surface of the water
film to the airflow.
[0144] The temperature of the air as pre conditioned by the
labyrinth of passages in the heat sink body may not be sufficient
under some of the stated conditions to affect the low vapor
pressure needed for the cooling load, External heating could be
implemented to achieve this.
[0145] The latter requirement could be alleviated by implementing
auxiliary heating external to the heat sink to augment the physical
limitation of providing the chamber for heating within the heat
sink. This procedure would provide the flexibility of extending
almost at will the capability of the heat sink. The process of
preheating the air adds a favorable contribution to this problem.
When the air is heated, the saturation level for water vapor rises
exponentially with the temperature rise. This implies that lower
volume of air flow is needed to carry the water vapor product of
vaporization. The silicon devices are capable of at least reaching
125C. With proper care and design on both the interface to the
computer chip and the pre heating higher temperature for the air
flow could be achieved. This further reduces the rate of air flow
needed. Tradeoffs are the reliability issue desired for the
semiconductor. The cooler the silicon more reliable and longer life
for the device. The other factors are aesthetic on the practical
temperature for the output air flow, and requirement for better
materials to handle the higher air temperature. The design of the
pre heater will dictate the volume of the heat sink. The pre heater
should not eliminate much of the highly conductive material used
for the heat sink to the point that it reduces the thermal
conductivity from the computer chip to the fins to which the water
film is introduced. The fins should be as short as possible to
reduce the effective thickness of the fins. Thus under some
circumstances the external preheating of the air flow is more
acceptable. This is true from the point of view that the power
needed to heat the reduce volume of air flow is small compared to
the benefits that would accrue with the cooling process. The fins
total surface area has to be designed such that the diffusion rate
and the capacity will not be limited by the area used for the
diffusion to convey the heat flux. Increasing the fin surface area
and minimizing the gaps between them would be parameters to be
considered. Decreasing the gap between the fins makes the air flow
laminar. If the boundary layer is desired to have as much vapor
pressure gradient as possible to enable the heat flux capacity
needed, then the air flow should be adjusted correspondingly. Again
in order to assure that the water delivery is metered to prevent
saturation in the air flow chambers.
[0146] Other procedures of implementing the delivery of water are
possible. The considerations on scaling buildup are one of the
factors of importance. These are subjective decision and amenable
to various degrees of variation.
[0147] For example the water delivery could be via other means of
transpiration using other topologies of the relationship between
the water container vessel and its introduction to the air flow
stream. Compromise on the ease of maintenance of scaling problem to
the economics of replacing the components are tradeoffs that have
to be considered. Also the maintenance as a result of scaling does
not have to require maintenance but if economically justifiable a
strategy of throw away replacement. The circuit for the decision on
how the air flow is controlled are subjective and not absolute.
Therefore the process indicated in this application would include
such possibilities and variations
[0148] Another version of the heat sink would be a modification of
FIG. (26) and FIG. (26a). The technology called Peltier heating and
cooling which depends on the Seebek effect on semiconductors are
well developed for commercial applications and are economically
viable. The implementation of added external heating is a practical
and natural extension of using the Peltier effect heating elements.
Packaging them would be also amenable to the size of the heat sink
because they can be small enough and that the energy requirement
for the pre conditioning of the air flow is minimal on heating
and/or cooling capability The Peltier heating elements could be
mounted on the side of the side sink as an extension of FIG. (26)
and FIG. (26a) where they would be attached modules on the side of
main block 260.
Description Third Embodiment
[0149] The third embodiment is an application of the process to new
air conditioning and refrigeration equipments.
[0150] Air conditioning or refrigeration systems are system level
type of designs. It is different from the upgrade discussed
previously because all tradeoff are available to be considered
together as an aggregate to be weighed with all attendant
requirements of economics, capitalization, reliability,
maintenance, aesthetics. This section as an embodiment shall focus
on the changes that could be implemented with the advantages of
vaporization in new designs for air conditioning or refrigeration
system of various sizes. Different applications shall be touched on
from small ones like portable units, central type as used in
residential units and the large units that are for example
represented for the condenser cooling by the use of water towers.
Embodiments that typically would apply the various items discussed
previously shall be considered. The implications of the advantages
provided by the use of vaporization shall also be discussed.
[0151] Considering only the condenser and also using the same fin
and tube technology that is very mature and economically viable,
the following are advantages in implementing the process. The other
developments that addresses the enclosure for the refrigerant to
improve its thermal conductivity which is a major portion of
temperature head with this process could be adopted when the
manufacturing process and volume is at the point of economic
viability. It does not of course preclude the activity of devising
other implementation of the condenser structure considering the
inherent physics of the vaporization process requirement. For
example modules that are extruded with chambers for the
refrigerants that do not necessarily depend on the linear feature
of the flow of refrigerant could be designed. Parameters to
optimize the labyrinth that would be created in this modules had
been studied by others using the existing copper tubes but adapted
to other internal and external configurations. It is known that for
a given geometry with considerations of thermal conductivity and
problems of liquid and vapor globs on the tubes, there exist
optimal length and dimensions The implementation of the
vaporization process is not altered because of these variations in
the physical nature of the refrigerant flow and enclosure.
[0152] The implementation of the vaporization process with the
attendant addition of various parameters for controlling the system
adds to flexibility, reliability, more effective maintenance
program, robustness and capability of synergistic operation with
other energy using equipments in the area or home.
[0153] The implementation also automatically reduces the size and
air flow needed for the cooling unit. Using the fin and tube
condenser as modules to create easy maintenance. It enables a
hierarchy of cells or modules as basic units for building and
upgrading systems. This enables the elimination or extension of
economic losses due to system downtime for maintenance. The
flexibility afforded for upgrades, e.g. the rule that there is
always a diminishing capability on large computer system
installation would make upgrades on cooling capacity easier and
could be predicted. This hierarchical structure would enable
seamless additions for increase cooling load requirements. The
upgrades could be implemented without system downtime since tapping
into the existing system could be designed such that such operation
is seamless. The progressing building block of FIG. (35) of
creating the system enables the scheduling of the maintenance of
portions of the system without affecting the capacity and
performance required of the system. Also the process enables the
location of the condenser indoors and reduction of size and
capitalization cost.
[0154] The basic cell module as an architecture can be as shown in
FIG. (21). The source of water head can of course be modified
together with the solenoid valve with other methods. However the
basic topology of being able to mix sensible and latent heat of
convection transport is shown in FIG. (21). A basic "cell" for
example could be 10 ton capacity system for large systems. Systems
for smaller commercial systems can have "cells" of smaller
capacity.
[0155] The implementation of the control, both from the cell level
and system level might be seamless to accommodate other existing
controllers if the basic "cell" structure has an independent
controller with the capability of communicating with the rest of
the "higher level cells" hierarchy. Breaking up the demarcation
between the other parts of the refrigeration system such as the
compressor, air handling systems will also be affected with regards
to the architecture of the system but I am not addressing these
issues.
[0156] Air conditioning systems with externally located water
towers could be implemented with smaller sizes that could be
located indoors. The system indoors can be designed to have a
hierarchy of components that would distinguish the level of both
cooling contribution and maintenance segmentation. The basic
condenser cell shall have a minimum cooling capacity that could be
configured to have embedded pre heating (pre conditioning) or a
basic condenser which will have all condenser fins and tubes to be
operated with vaporization with the use of a pre conditioning
chamber FIG. (21) and provide the pre conditioning of cooling
and/or heating as discussed previously. This process enhances the
efficiency and capability of cooling capacity and performance to
ambient temperatures that are high with corresponding high relative
humidity. The inputs to these pre conditioning chambers shall have
dampers to regulate the portion of ambient outside air or indoor
air for replenishment. The plumbing of the air flow and also the
water delivery valve control have to be implemented per situation
of type of pre conditioning.
[0157] FIG. (21) is a concept for a general pre conditioning of air
as source for the condenser using vaporization for cooling. We know
that warming up the air increases the water vapor capacity of the
air and allows us to use less volume of air with the controller to
transport the heat flux. This was applied to the computer chip
cooling and enabled us to cool and get rid of high heat flux. This
is a case in large systems where a general air pre conditioning is
applied, i.e. both cooling and heating of the air is used for pre
conditioning. FIG. (21a) is a curve that justifies the concept. The
equation for saturated water vapor at temperature i is given on
first line. Ilow is the number of degrees C. that the cooling is
performed. The curves show when the air is warmed in this case 3
times ilow above the ambient temperature. The total energy to cool
and heat for pre conditioning the air is trace 5. It consist of the
latent heat to condense to the dew point extra water vapor at
90.5.degree. F. with a relative humidity of 80% and the sensible
heat of lowering the temperature by 4.5.degree. F. and raising the
temperature by 13.5.degree. F. above 90.5.degree. F. The enabled
capacity for cooling with the transpiration with this process is
trace 2. The graph shows that if the cooling 9F and warm the air
temperature by 13.5 F above original ambient (90.5 F), then 1 cubic
meter per second air flow would enable 100 kilowatts of cooling
with transpiration. The SOP for the cooling using original
equipment would require approximately 7 kilowatt of fan power. The
effective power that is used on the air volume is approximately
also 7 kilowatts. However since we are using an air conditioner
with a given COP, then assuming the air conditioner has a COP or
3.5, then the actual power usage is 2 kilowatts. The advantage is
not only on the net power consumption but also it enables lowering
the air flow by a factor of 25 for the vaporization Thus the air
pre conditioning is beneficial both on energy and also lower the
air flow with reduction in physical size of the condenser
[0158] The equipment used for this would be a standard air
conditioning system. A tighter control on the temperature and
monitoring the cooling to avoid freezing may be alleviated with an
external controller 518 where sensor information from the cooled
chamber and the warm chamber are obtained from sensor 508 and
sensor 510 respectively. The cooling equipment air flow are
separated as typical for air conditioners. The cooled air output
521 is routed from the output of the evaporator 520. The input air
to the evaporator consist of metering mixture of air from the
cooled chamber 526 and the outside ambient air 500 and the air flow
output from the transpiration equipment with the dampers 504 and
502 and 506. Similarly the warm air is circulated through the
condenser. The input air to the condenser is 516. The air pre
conditioning equipment is the usual convective type condenser and
evaporator with air as the transport material. The cooling strategy
is to bring the room air temperature to a low level with the intent
of removing all water vapor such that the cooled air is at its dew
point. The warm air chamber 528 on the other hand is the air that
is involved with the condenser. This warm air chamber will
circulate the air just like the evaporator 520 in the cool chamber.
Assuming care is exercised such that further heat energy losses in
both chambers are mitigated, then the energy required would be as
defined by the COP of the equipment. The air pre conditioning
chamber 524 consist of cooled air chamber 526 and a warm air
chamber 528. The air conditioner used for the air pre conditioning
circulates air separately through the evaporator (cooled chamber)
and the condenser (warm chamber)
[0159] Rough economic study had been made on applying the process
on new plants and the return on investment showed promising
benefits. They are contributed both by the initial reduction of
capitalization and also on the large savings on the recurring cost
because of the advantages of efficiency and maintenance.
[0160] The method followed in the process for addressing the
problems of scaling reduces the recurring cost of maintenance and
also avoids or logistically delay total system downtime for
maintenance.
[0161] The implementation of the different aspects of the process
to new equipments would result to the following:
Portable Air Conditioners:
[0162] (1) Smaller size. [0163] (2) Portability to the strict sense
of the word because of size and some cases the convenience of
eliminating the umbilical cords associated with the usual VCRS type
portable air conditioners air flow. [0164] (3) Indoor location
could benefit from the side effect from the vapor output that could
effectively improve comfort level depending on the environment.
[0165] (4) Economic benefits since local cooling on demand can
easily be implemented. [0166] (5) Portability and extension of
cooling capacity of a given unit with the property of preheating is
available.
Residential Central Air Conditioners
[0166] [0167] (1) Smaller size. [0168] (2) Indoor location with
advantages of consistency of environment for operation and
improvement of reliability and life. Reduce volume of air flow is
an advantage to lowering the noise level indoors. [0169] (3)
Synergistic operation with other energy using devices at home.
Higher Efficiency. [0170] (4) Better control for comfort level.
[0171] (5) Extension of cooling capability because of
implementation of preheating feature. [0172] (6) Seamless increase
of cooling capacity. This is very common with computer server
rooms.
Utility and Other Large Cooling Systems
[0172] [0173] (1) Modular cells leads to manageable maintenance
that logistically could complete full system maintenance regularly.
[0174] (2) Modular cells does not affect the local downtime of the
smaller modules comprising the whole system. [0175] (3) Condenser
cooling system could be completely located indoors. This
arrangement lends further control leeway for the vaporization
system because choice of air flow source could be chosen from
either the conditioned indoor air or outdoor air. [0176] (4)
Control to accommodate demand for cooling for the whole system
leads to flexibility and economic operation. [0177] (5) System
could be located indoors and avoid all the disadvantages discussed
in connection with bio film and scaling, degradation of equipment
because of exposure to the elements. The procedures which are
generally expensive and not environmentally friendly on treatment
of cooling water are alleviated because of the application of the
metering process. [0178] (6) Reduction of initial capitalization
for new plants. [0179] (7) Reduction in size. For example it is
very doable to reduce the volume size of the active components for
the condenser compared to the water tower cooler by 50 times.
[0180] (8) Other additional benefits on reduction of losses such as
energy for pumping the cooling water in the towers, the large
expense on water replenishment because of the evaporation of water
not involved in the vaporization process, reduction in energy usage
for air flow because of the reduction in air flow requirements.
* * * * *