U.S. patent application number 11/789636 was filed with the patent office on 2008-10-30 for method for improving efficiency in heating and cooling systems.
Invention is credited to Mingsheng Liu.
Application Number | 20080264086 11/789636 |
Document ID | / |
Family ID | 39885398 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080264086 |
Kind Code |
A1 |
Liu; Mingsheng |
October 30, 2008 |
Method for improving efficiency in heating and cooling systems
Abstract
A method for improving efficiency in heating and cooling systems
which includes the steps of providing speed and pressure monitoring
devices for monitoring and measuring the operational speed (OS) and
the head (H.sub.R) of the fan or pump and providing a flow rate
monitoring device for monitoring and measuring the fluid flow rate
(Q) for fluid flowing through the fan or pump. The OS, H.sub.R and
Q for the fan or pump would be periodically obtained from the speed
and pressure monitoring devices and the flow rate monitoring
device, and the operating S-value of the heating and cooling system
would be determined by applying the formula
S-value=H.sub.R/(Q.sub.R).sup.2, thereby obtaining a measurable
single value representative of the overall efficiency of the
heating and cooling system.
Inventors: |
Liu; Mingsheng; (Omaha,
NE) |
Correspondence
Address: |
Adam H. Jacobs
Suite726, 1904 Farnam Street
Omaha
NE
68102
US
|
Family ID: |
39885398 |
Appl. No.: |
11/789636 |
Filed: |
April 25, 2007 |
Current U.S.
Class: |
62/180 |
Current CPC
Class: |
F24F 11/83 20180101;
F24F 11/77 20180101; F24F 2140/12 20180101; F24F 11/46 20180101;
Y02B 30/70 20130101 |
Class at
Publication: |
62/180 |
International
Class: |
F25D 17/00 20060101
F25D017/00 |
Claims
1. A method for improving efficiency in HVAC systems, the HVAC
system having at least one of a fan and a pump, a motor for driving
the pump, at least one air handling unit (AHU), and a
heating/cooling system, said method comprising the steps: providing
speed and pressure monitoring means for monitoring and measuring
the operational speed (OS) and the head (H.sub.R) of the at least
one of a fan and a pump; providing flow rate monitoring means
operatively associated with the at least one of a fan and a pump
for monitoring and measuring the fluid flow rate (Q) for fluid
flowing through the at least one of a fan and a pump; periodically
obtaining the OS, H.sub.R and Q for the at least one of a fan and a
pump from said speed and pressure monitoring means and said flow
rate monitoring means; determining the operating S-value of the
HVAC system by applying the formula;
S-value=H.sub.R/(Q.sub.R).sup.2 thereby obtaining a measurable
single value representative of the overall efficiency of the HVAC
system.
2. The method of claim 1 further comprising the step of determining
the S-value set point of the HVAC system, said S-value set point
representing the optimum operating efficiency of the system
3. The method of claim 2 wherein said step of determining said
S-value set point comprises providing the design head (H.sub.D) and
design fluid flow rate (Q.sub.D) for the at least one of a fan and
a pump in the HVAC system and entering the H.sub.D and Q.sub.D
values into the equation: S-value set
point=H.sub.D/(Q.sub.D).sup.2, thereby obtaining a value for the
S-value set point for the HVAC system.
4. The method of claim 2 wherein said step of determining said
S-value set point comprises the steps: running the at least one of
a fan and a pump at its low speed limit; measuring the fluid flow
rate and head of the at least one of a fan and a pump; determining
the initial operating S-value (S.sub.1) as the ratio of the head
and the square of the fluid flow rate; increasing the operational
speed of the at least one of a fan and a pump approximately ten
percent; measuring the second fluid flow rate and second head of
the at least one of a fan and a pump; determining a second S-value
(S.sub.2) as the ratio of the second head and the square of the
second fluid flow rate; comparing S.sub.2 to S.sub.1 to determine
S.sub.2 is approximately five percent (5%) greater than S.sub.1,
assigning S.sub.1 the value of S.sub.2 and repeating said
increasing, measuring, determining and comparing steps if S.sub.2
is not approximately five percent (5%) greater than S.sub.1; and
setting said S-value set point as the average of S.sub.1 and
S.sub.2 if S.sub.2 is approximately five percent (5%) greater than
S.sub.1.
5. The method of claim 2 further comprising the step of applying
said operating S-value to optimize operation of the at least one of
a fan and a pump by adjusting the operational speed (OS) of the at
least one of a fan and a pump such that H.sub.R/(Q).sup.2
approaches said S-value set point.
6. The method of claim 2 further comprising the step of multiplying
the S-value set point by a factor of .alpha., where .alpha. is a
safety factor which is a function of the fan/pump flow to prevent
overloading of the fan/pump and is calculated by the formula
.alpha.=(Q/Q.sub.D).sup.-n, where .eta. is a constant between zero
(0) and 0.5.
7. A method for improving efficiency in heating and cooling
systems, the heating and cooling system having at least one of a
fan and a pump, a motor for driving the pump and a heating/cooling
system, said method comprising the steps: providing speed and
pressure monitoring means for monitoring and measuring the
operational speed (OS) and the head (H.sub.R) of the at least one
of a fan and a pump; providing flow rate monitoring means
operatively associated with the at least one of a fan and a pump
for monitoring and measuring the fluid flow rate (Q) for fluid
flowing through the at least one of a fan and a pump; periodically
obtaining the OS, H.sub.R and Q for the at least one of a fan and a
pump from said speed and pressure monitoring means and said flow
rate monitoring means; obtaining an S-value set point for the HVAC
system representing generally the optimum efficiency value for the
HVAC system; determining the operating S-value of the HVAC system
by applying the formula; S-value=H.sub.R/(Q.sub.R).sup.2 thereby
obtaining a measurable single value representative of the overall
operating efficiency of the HVAC system; and comparing said
operating S-value with said S-value set point to optimize operation
of the at least one of a fan and a pump by adjusting the
operational speed (OS) of the at least one of a fan and a pump such
that said operating S-value (H.sub.R/(Q).sup.2) approaches said
S-value set point.
8. The method of claim 7 wherein said step of determining said
S-value set point comprises providing the design head (H.sub.D) and
design fluid flow rate (Q.sub.D) for the at least one of a fan and
a pump in the heating and cooling system and entering the H.sub.D
and Q.sub.D values into the equation: S-value set
point=H.sub.D/(Q.sub.D).sup.2, thereby obtaining a value for the
S-value set point for the heating and cooling system.
9. The method of claim 7 wherein said step of determining said
S-value set point comprises the steps: running the at least one of
a fan and a pump at its low speed limit; measuring the fluid flow
rate and head of the at least one of a fan and a pump; determining
the initial operating S-value (S.sub.1) as the ratio of the head
and the square of the fluid flow rate; increasing the operational
speed of the at least one of a fan and a pump approximately ten
percent; measuring the second fluid flow rate and second head of
the at least one of a fan and a pump; determining a second S-value
(S.sub.2) as the ratio of the second head and the square of the
second fluid flow rate; comparing S.sub.2 to S.sub.1 to determine
S.sub.2 is approximately five percent (5%) greater than S.sub.1,
assigning S.sub.1 the value of S.sub.2 and repeating said
increasing, measuring, determining and comparing steps if S.sub.2
is not approximately five percent (5%) greater than S.sub.1; and
setting said S-value set point as the average of S.sub.1 and
S.sub.2 if S.sub.2 is approximately five percent (5%) greater than
S.sub.1.
10. The method of claim 7 further comprising the step of
multiplying the S-value set point by a factor of .alpha., where
.alpha. is a safety factor which is a function of the fan/pump flow
to prevent overloading of the fan/pump and is calculated by the
formula .alpha.=(Q/Q.sub.D).sup.-n, where .eta. is a constant
between zero (0) and 0.5.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates generally to systems and
methods for improving the efficiency of HVAC systems and, more
particularly, to a method for improving efficiency in HVAC systems
which includes the steps of providing speed and pressure monitoring
devices for monitoring and measuring the operational speed and head
pressure of the fan or pump of the air or water-based system,
providing a fluid flow rate monitoring device which will measure
the fluid and flow rate of fluid flowing through the fan or pump,
periodically obtaining the operational speed, head pressure, and
fluid flow rate from the monitoring devices, determining the
S-value of the HVAC system by applying the formula H/Q squared and
applying the S-value to optimize operation of the fan or pump by
adjusting the operational speed such that the measured S-value
approaches the set point S-value representing optimum flow
efficiency.
[0003] 2. Description of the Prior Art
[0004] Fans and pumps are the major devices used to transport air
or liquid in HVAC systems and through processing devices used in
manufacturing concerns, such as those shown in the examples of the
prior art of FIGS. 2 and 3. The basic function of such fans and
pumps is to ensure enough air and water flow through the end
devices. However, the required flow often changes with time and the
load placed on the end devices, thus requiring some degree of flow
modulation in order to permit proper heating or cooling of the end
device. The required flow modulation is often achieved using the
following two steps: [0005] 1. Modulate the fan/pump speed as the
terminal load changes. The fan/pump speed would be indirectly
controlled by a pressure or differential pressure set point. For
example, the fan in an air handling unit is often controlled to
maintain the static pressure at two-thirds (2/3) of the preset
system value downstream of the main duct. In a related system, a
differential pressure sensor is often installed in a liquid loop,
and when the differential pressure differs from the set point, the
pump speed is changed to ensure the set point. [0006] 2. An
individual modulation damper/valve is installed for each end device
and a preset damper value is assigned to each end device. The
damper/valve is used to maintain the required flow when the load
changes by permitting increased or decreased fluid flow to the end
device.
[0007] In the majority of HVAC and industrial chilling systems, the
set point of static pressure/differential pressure is often
determined under the maximum load conditions. Under partial load
conditions, this control approach has the following drawbacks: One,
it consumes excessive fan/pump energy, approximately thirty percent
more fan energy than is used for a typical variable air volume air
handling unit; two, it exposes the dampers/valves in the end
devices to excessive pressures which will eventually cause
malfunction, thus requiring frequent adjustment of the control loop
gains to maintain stable dampers/valves control, and since it is
impossible to properly perform this process in many applications,
the process will cause significant control device damage and
unstable control; and three, excessive air leakage in the ductwork
and air/water leakage through closed dampers/valves will occur due
to the increased operational pressures, and consequently, thermal
energy is wasted, and for example for a typical AHU, ten percent or
more thermal energy is wasted.
[0008] It has further been proposed in the HVAC industry to provide
a differential pressure/static pressure reset system to improve the
system operation. The following approaches are often proposed: One,
modulate the fan/pump operational speed to maintain at least one
damper/valve at full open; or two, reset the set point based on the
rule of thumb. While the first approach is ideal theoretically, it
has been seldom used due to a number of practical issues. This
method cannot work properly when end devices are malfunctioning. It
also creates large amount of information transfer in the network,
which often overloads the network and breaks down the system. The
second approach would not achieve the optimum results due to the
dependence of experience. There is therefore a need for a system or
method which will improve and optimize the efficiency of the HVAC
or industrial chilling system, yet will do so while not requiring
significant modifications to the already-existing system, or which
relies on outdated or non-functional system elements such as
original equipment pressure sensors for reading critical system
information.
[0009] It is therefore an object of the present invention to
provide an improved method for improving the efficiency of an HVAC
or industrial chilling or heating system.
[0010] Another object is to provide an improved method for
improving the efficiency of an HVAC or industrial chilling or
heating system which will obtain real-time information from the
operation of the fan/pump which feeds the system, including
fan/pump head and fan/pump flow rate, determine an operating
S-value by dividing the head by the flow rate squared, and compare
that to an optimum S-value set point initially determined for the
system.
[0011] A further object of the present invention is to provide an
improved method for improving the efficiency of an HVAC or
industrial chilling or heating system in which the operating speed
of the fan/pump is increased or decreased to bring the operating
S-value into accordance with the S-value set point representing the
optimum efficiency for the system.
[0012] Still another object is to provide an improved method for
improving the efficiency of an HVAC or industrial chilling or
heating system which does not require system information obtained
from previously installed gauges and sensors which may be damaged
or non-functional or may be unavailable due to their location being
unknown within the building in which the HVAC system is
installed.
[0013] Finally, an object of the present invention is to provide an
improved method for improving the efficiency of an HVAC or
industrial chilling or heating system which is relatively simple
and straightforward in design and construction and is safe,
efficient and effective in use.
SUMMARY OF THE INVENTION
[0014] The present invention provides a method for improving
efficiency in HVAC systems, the HVAC system having at least one of
a fan and a pump, a motor for driving the pump, at least one air
handling unit (AHU), and a heating/cooling system, the method
comprising the steps of providing speed and pressure monitoring
devices for monitoring and measuring the operational speed (OS) and
the head pressure (H.sub.R) of the at least one of a fan and a pump
and providing a flow rate monitoring device operatively associated
with the at least one of a fan and a pump for monitoring and
measuring the fluid flow rate (Q) for fluid flowing through the at
least one of a fan and a pump. The OS, H.sub.R and Q for the at
least one of a fan and a pump is then periodically obtained from
the speed and pressure monitoring devices and the flow rate
monitoring device, and by utilizing those readings, the operating
S-value of the HVAC system is obtained by applying the formula:
S-value=H.sub.R/(Q.sub.R).sup.2, thereby obtaining a measurable
single value representative of the overall efficiency of the HVAC
system. The operating S-value is then utilized to optimize
operation of the at least one of a fan and a pump by adjusting the
operational speed (OS) of the at least one of a fan and a pump such
that H.sub.R/(Q).sup.2 approaches the S-value set point of the HVAC
system thereby increasing the operational efficiency of the HVAC
system.
[0015] The present invention thus provides a substantial
improvement over those systems and methods found in the prior art
which are designed to provide for adjustment to HVAC systems for
increasing efficiency. Specifically, because the method of the
present invention does not require use of the remote pressure
sensor already installed in the HVAC system in order to determine
the most efficient operating speed for the pump or fan, it is not
necessary for a user of the present invention to determine the
location of the originally installed pressure sensor, determine if
it is working correctly, and provide preventive maintenance to
maintain the pressure sensor in its properly operating condition.
Furthermore, because the system and method of the present invention
generally reduces efficiency determinations to the proper operation
of the fan or pump in connection with the HVAC system, it is far
easier for a user to implement the method of the present invention
as compared to those intricate and failure-prone systems and
methods found in the prior art. Finally, because the present
invention is usable not only with HVAC systems, but with any
cooling or heating system which includes a fan or pump for driving
fluid through the system, it may be adapted and used with many
industrial chilling or heating systems which bear little if any
resemblance to HVAC systems yet, because they include a pump or fan
which can be controlled by an implementation of the present
invention to increase efficiency, improvement in the efficiency of
those industrial systems may be achieved through implementation of
the present invention.
[0016] In the preferred embodiment, the proposed S-method will
provide optimal and reliable fan and pump control, which will:
[0017] 1. Maximize the fan/pump efficiency and save electrical
energy consumption.
[0018] 2. Provide stable damper/valve control.
[0019] 3. Eliminate excessive thermal energy waste.
[0020] 4. Eliminate the need of the static pressure sensors in fan
systems and the differential pressure sensors in pump systems.
[0021] It is therefore seen that the present invention provides a
substantial improvement over those systems and methods found on the
prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic diagram of the HVAC system outfitted
with the system and method of the present invention to increase the
efficiency of the HVAC system;
[0023] FIGS. 2 and 3 are schematic diagrams showing air and water
flow systems of the prior art illustrating the disadvantages of
these systems;
[0024] FIG. 4 is a schematic diagram of the various modules of the
present invention; and
[0025] FIGS. 5-11 are flow chart diagrams which disclose in detail
the various modules of the system and method of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] The S-value determination method is an intelligent control
algorithm/system for optimally controlling fan/pump speed in
heating ventilation and air-conditioning (HVAC) systems, such as
those shown in FIG. 1, and in industrial chilling and heating
systems having fans and/or pumps therein. This method intelligently
modulates the fan (pump) speed to satisfy the desired flow, to
maximize the energy system efficiency and to warrant stable end
user device control. This method can be applied to variable air or
water volume systems in HVAC systems for fan and pump speed
control, and to industrial processes as well. FIG. 1 presents the
schematic diagram of the S-value determination method, and in the
preferred embodiment, the present invention would include the
following sensors or signal sources: A differential pressure sensor
or signal source is connected to the fan/pump to measure the fan
head or pump head pressure, and a fluid flow meter is provided in
the system to measure fan airflow or pump flow. There are many
different methods and devices which can be used to obtain this
data, including using the fan airflow station or pump flow station
as disclosed in U.S. patent application Ser. Nos. 11/498,539 and
11/491,767, or by using conventional flow measurement meters such
as those commonly used in fluid flow applications. Furthermore, the
present invention would provide a power meter or signal source,
which can be a built-in meter in a Variable Frequency Drive (VFD)
which is designed to measure the true power output of the
motor.
[0027] In the preferred embodiment, the method of the present
invention includes seven modules, as shown best in FIG. 4. The
first module is the start module, which ramps up the fan/pump speed
from zero to a predetermined level (for example, to fifty percent
speed) within the given time period (for example, over thirty
seconds).
[0028] When the first module function is completed, the second
module is engaged. The sampling module processes the signals from
the sensors, devices and resources to obtain real time values for
the fan/pump head, fan/pump speed, airflow or water flow and the
motor power consumption. In addition, the sampling module may also
receive the static pressure signal for a fan system, and
differential pressure signal for a pump system. In the preferred
embodiment, the static pressure sensor is typically installed
downstream of the fan to measure the duct static pressure or total
pressure, with the typical locations being approximately two-thirds
downstream of the main duct or at the end of the main duct.
Likewise, the differential pressure sensor is typically installed
downstream of the pump. The typical location is often at the end of
the loop. It should be noted, however, that the static pressure
sensor and the differential loop pressure sensor are optional. The
preferred sampling system for each of the sensor and devices would
involve processing all signals using a moving average, and the time
period between periodic sampling would preferably be in a range of
five seconds to several minutes.
[0029] The third module is the fan/pump flow station module, which
determines the fan/pump flow based on measured fan/pump speed,
fan/pump head and fan/pump curves. As was stated previously, this
module would preferably be based on U.S. patent applications No.
11/498,539 and 11/491,767. The fan airflow/pump water flow can also
be obtained from the conventional flow meters which are stationed
within the HVAC system.
[0030] The fourth module is the S-value set point module, which
determines the set point of the S-value. S is the system resistance
factor. Two options exist depending on the selection of the
pressure or the differential pressure signals. The first option is
to define the S-value as the ratio of the fan/pump head and the
square of the fan/pump-flow. The second option is to define the
S-value as the ratio of the static pressure (static pressure
reading) and the fan airflow, or as the ratio of the differential
pressure (differential pressure sensor reading) and the pump flow.
The details of selecting S-value set points are discussed in the
next section.
[0031] The fan/pump head module determines the set point of the
fan/pump head or the static pressure set point or differential
pressure set point depending on the selection of the S-values. The
set point of the fan/pump head, static pressure, or differential
pressure is as the product of the set point of S and the square of
the fan/pump flow.
[0032] The speed control module is a PI loop, which modulates the
fan/pump speed to maintain the actual fan/pump head, or fan static
pressure, or differential pressure at its set point, which is
determined by the fan/pump head module.
[0033] The output module produces the following information:
fan/pump efficiency, equivalent pump working point (percentage of
fan/pump flow, percentage of fan/pump head at one hundred percent
speed), and fan/pump power. The fan/pump efficiency is determined
as the ratio of the useful mechanical work and the actual power
consumption. The useful work input is the product of the fan/pump
flow and head, which shall be converted into proper units. The
output module may include standard network communication port or
standard analog output port. The method of the present invention
may also include standard interfaces to communicate with other
controllers.
[0034] The set point of the S-value, which sets the optimal level
of efficiency for the system with which the present invention is
being used, is preferably determined using one of the following
method. First, the S-value set point may be determined as the
product of a coefficient and the ideal S-value which is determined
as the ratio of the design fan/pump head and the square of the
design airflow/water flow. The coefficient can be in a range of 1
to 1.5, with the resulting equation appearing as follows:
S.sub.set point=.alpha.(H.sub.D/(Q.sub.D).sup.2)
where .alpha. is a safety factor, which can be a function of the
fan/pump flow to prevent overloading of the fan/pump, H.sub.D is
the design fan or pump head and Q.sub.D is the design fluid
flow.
[0035] Second, the S-value set point may be determined using the
experimental trial method which involves the following steps.
First, the fan/pump is run at its low speed limit and the measured
airflow/water flow and fan/pump head are recorded. Determine the
first operating S-value (S.sub.1) as the ratio of the recorded head
and the square of the recorded flow. The fan/pump would then be run
at ten percent higher operating speed than its low limit, and again
the measured airflow/water flow and fan/pump head would be
recorded. Determine the second S-value (S.sub.2) in the same manner
as the first S-value (S.sub.1) using the newly acquired recorded
head and recorded flow. If S.sub.2 is five percent (5%) greater
than S.sub.1 (this ratio being adjustable depending on the specific
system, but generally five percent is the preferred percentage to
be used for the calculation), then determine the minimum S-value
set point as S.sub.2 or the average of S.sub.1 and S.sub.2. If it
is not, the fan/pump speed would be increased at an interval of ten
percent (adjustable) until the current S-value (S.sub.2) is five
percent (adjustable) greater than the previously obtained S value
(S.sub.1). This method is best suitable for systems which monitor
the control damper information or control valve position when
pneumatic controllers are used in the terminal boxes or the control
valves.
[0036] Alternatively, the experimental trial method may involve
analysis of the damper/valve positions in the following manner. The
fan/pump speed would be modulated until a certain percentage of the
dampers/valves in the system are near full open while all zone
temperatures or discharge air temperatures of the coils are
maintained at the preferred set point. At this point, the fan/pump
head and the air/water flow would be recorded and this would
represent the optimal operational values for the system. For either
of the experimental trial methods, however the maximum S-value
obtained would be used as the S-value set point for the system, and
this ratio would provide the basis for adjustment of the operating
characteristics of the fan/pump during operation of the system.
[0037] It should be noted that the safety factor .alpha. referred
to previously will vary due to fluctuations in the load placed on
the system. For example, at partial load conditions, the load
ratios vary from end device to end device and consequently, the
safety factor should increase as the fan/pump flow decreases.
Therefore, in the preferred embodiment, the safety factor would
generally be expressed as the following formula:
.alpha.=(Q/Q.sub.D).sup.-n
where .eta. is a constant which varies between 0 to 0.5, depending
on the flow rate and pump or fan operational characteristics.
[0038] The operational elements of the method of the present
invention are best shown in the flow charts of FIGS. 5-11 as
including numerous steps which, when applied to an HVAC system or
industrial chilling or heating system, will invariably improve the
efficiency of the system over time, barring any unforeseen
circumstances or system failures. A detailed discussion of each of
the elements of flow charts found in FIGS. 5-11 is not deemed
necessary, as the flow charts are self-explanatory and would
generally be implemented via a computer program or the like which
executes the various steps and includes interfaces with each of the
operative elements of the HVAC system or industrial chilling or
heating system, as shown in FIG. 1. However, it should be noted
that FIGS. 9 and 10 disclose what may be deemed "the heart" of the
present invention, in that modulation and control of the fan/pump
operational speed is performed via the implementation of the
fan/pump speed control module. Specifically, it should be noted
that once the fan/pump head and the fan/pump fluid flow rate have
been established via sampling by the speed and pressure monitoring
device and the flow rate monitoring device, the operating S-value
formula is applied to obtain a specific ratio based on current
operation of the system. This ratio is then compared to the S-value
set point obtained from the system which represents the optimum
operating efficiency of the system, namely, when the pump or fan is
operating at one hundred percent capacity and all of the various
dampers or other resistance factors in the system are open to
provide the least resistance through the system for the air or
liquid flowing therethrough. If the ratio of fan/pump head to
fan/pump fluid flow squared obtained from the actual operation of
the fan/pump is approximately equal to or close to the optimum
ratio obtained previously, the system is functioning at or near
optimum efficiency and adjustment to the operating speed of the
fan/pump is not absolutely necessary. However, if the ratio
obtained is significantly higher or lower than the optimum ratio,
the system determines this and the operating speed of the fan/pump
is consequently increased or decreased to increase or decrease the
fan or pump head in order to bring the ratio closer into accordance
with the preferred optimum ratio which was initially determined by
either application of the design head and flow rate formula or the
experimental trial formula as applied to the system. The system
periodically checks the operating S-value and performs the same
comparison with the optimum ratio and, in this manner, the system
of the present invention optimizes the operation of the HVAC system
or industrial chilling or heating system with which it is
connected, thereby significantly increasing the efficiency with
which the system is being operated.
[0039] The present invention provides many advantages over those
efficiency improvement systems and methods found in the prior art.
For example, elimination of the static pressure sensor and
differential pressure sensor in the ductwork and liquid loops will
further ensure reliable system operation. As was discussed
previously, in real-life engineering projects, the locations of
these sensors are often hard to find. Consequently, repair and
replacement of damaged or non-functional sensors is rarely, if
ever, performed. Due to these malfunctions of the sensors, it
causes significant amount of energy waste as well as poor comfort
in the HVAC system. Also, the present method and system maximizes
the fan/pump efficiency by minimizing the fan/pump head and
reducing air leakage through the ductwork and end devices, and also
reduces water leakage through closed valves. Finally, the overall
system stability is significantly improved and damper and actuator
damage is minimized.
[0040] It is to be understood that numerous additions,
modifications and substitutions may be made to the present
invention which fall within the intended broad scope of the
appended claims. For example, the specific steps disclosed in the
flow charts of FIG. 5-11 may be modified or changed so long as the
intended general function of comparing the operational S-value to
the optimum S-value set point initially obtained by the system is
periodically performed. Furthermore, implementation of the
operational elements of the present invention may be modified or
changed, as, for example, the speed and pressure monitoring devices
and flow rate monitoring devices may be of any appropriate type so
long as accurate readings of those speeds, pressures and flows may
be obtained from the HVAC system or industrial system with which
the invention is being used. Finally, although the present
invention has been described with some particularity regarding
obtaining of the initial S-value set point for the system, it
should be understood that any appropriate method or system may be
used to determine the S-value set point so long as the S-value set
point obtained through the alternative methods generally conforms
to the values expected when the methods disclosed above are applied
to the same HVAC system or industrial system.
[0041] There has therefore been shown and described a method for
improving efficiency in HVAC and industrial chilling and heating
systems which accomplishes at least all of its intended
objectives.
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