U.S. patent application number 11/882919 was filed with the patent office on 2009-02-12 for ice storage constant temperature air conditioning system having divided refrigerant.
This patent application is currently assigned to NAN KAI INSTITUTE OF TECHNOLOGY. Invention is credited to Chin-Hsin Hsiao, Ming-Jer Hsiao.
Application Number | 20090038320 11/882919 |
Document ID | / |
Family ID | 40345219 |
Filed Date | 2009-02-12 |
United States Patent
Application |
20090038320 |
Kind Code |
A1 |
Hsiao; Ming-Jer ; et
al. |
February 12, 2009 |
Ice storage constant temperature air conditioning system having
divided refrigerant
Abstract
An ice storage constant temperature air conditioning system
having divided refrigerant has a refrigerant divider to divide
refrigerant flow into two ducts. The first duct is connected to an
evaporator to absorb a great amount of latent heat to generate
refrigeration. The refrigerant flows to an ice storage refrigerant
loop of an ice storage tank to store ice. The second duct directly
sends the refrigerant to the ice storage refrigerant loop to store
the ice. Hence the refrigerant can be fully used or used in a
divided fashion. A condensate collection tray is provided below the
evaporator to recycle heat of low temperature condensate during
operation of air conditioning to automatically replenish the chill
water of the ice storage tank. The refrigerant at the condensate
outlet is cooled during ice storing or ice melting period to become
a subcooling liquid refrigerant to enhance refrigeration
effect.
Inventors: |
Hsiao; Ming-Jer; (Nantou
City, TW) ; Hsiao; Chin-Hsin; (Nantou City,
TW) |
Correspondence
Address: |
Joe McKinney Muncy
PO Box 1364
Fairfax
VA
22038-1364
US
|
Assignee: |
NAN KAI INSTITUTE OF
TECHNOLOGY
|
Family ID: |
40345219 |
Appl. No.: |
11/882919 |
Filed: |
August 7, 2007 |
Current U.S.
Class: |
62/59 |
Current CPC
Class: |
Y02E 60/147 20130101;
Y02E 60/14 20130101; F25D 16/00 20130101; F24F 5/0017 20130101 |
Class at
Publication: |
62/59 |
International
Class: |
F24F 5/00 20060101
F24F005/00 |
Claims
1. An ice storage constant temperature air conditioning system
having divided refrigerant, comprising: a compressor to compress
the refrigerant to become over-heated in a gas phase; a condenser
to receive and cool the over-heated gas refrigerant to become a
liquid phase; and a refrigerant divider to receive the cooled and
liquid refrigerant through a liquid duct and automatically divide
the liquid refrigerant into a first duct and a second duct; wherein
the cooled and liquid refrigerant flows through the first duct and
a heat exchanger located thereon to become a subcooling liquid
refrigerant at a high pressure and a low temperature, the
subcooling liquid refrigerant passing through an air conditioning
expansion valve to become a saturated and mist type refrigerant in
liquid and gas phases to enter an evaporator, the evaporator
absorbing a great amount of latent heat and sensible heat to
generate refrigeration, residual refrigerant entering an ice
storage refrigerant loop to store ice; wherein the second duct
delivers a portion of the cooling liquid refrigerant to the ice
storage refrigerant loop after being expanded through an ice
storage expansion valve to absorb a great amount of latent heat to
store the ice; the refrigerant in the ice storage refrigerant loop
being sent to the compressor through a gas duct to complete a
refrigerant circulation cycle.
2. The ice storage constant temperature air conditioning system of
claim 1, wherein the refrigerant divider closes the first duct to
allow all of the refrigerant to flow into the second duct during a
no load condition of a cooling room.
3. The ice storage constant temperature air conditioning system of
claim 1, wherein the refrigerant divider controls the ratio of the
refrigerant in the first duct and the second duct according to a
room temperature during a low load condition of a cooling room so
that the refrigerant amount in the first duct alters according to
required amount of the refrigerant in the evaporator and the rest
of the refrigerant is distributed to the second duct.
4. The ice storage constant temperature air conditioning system of
claim 1, wherein the refrigerant divider closes the second duct to
allow all of the refrigerant to generate a phase change and flow
into the evaporator through the first duct during a full load
condition of a cooling room.
5. The ice storage constant temperature air conditioning system of
claim 1, wherein the refrigerant divider channels all of the
refrigerant to the evaporator through the first duct and the heat
exchanger melts the ice during a high load condition of a cooling
room, and cooled energy in the ice stored in a no load condition
and a low load condition of a cooling room is released.
6. The ice storage constant temperature air conditioning system of
claim 1 further having a condensate collection tray located below
the evaporator to recycle heat of low temperature condensate
generated during operation of air conditioning to automatically
replenish chill water in an ice storage tank of the system.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an ice storage constant
temperature air conditioning system and particularly to an ice
storage technique that adopts divided refrigerant to allow a
refrigerant system to divide and distribute the refrigerant
according to the load of an air conditioning room to fully or
partially use the refrigerant to effectively transfer energy and
achieve optimum operation effect.
BACKGROUND OF THE INVENTION
[0002] When water is frozen to become ice the energy is stored to
become "latent heat". The latent heat in such an occasion is 79
KCAL/KG. A general air conditioning system has chill water at a
maximum temperature about 15.degree. C. Thus when the water of
15.degree. C. is frozen to become ice of 0.degree. C. the total
energy being stored is 94 KCAL/KG.
[0003] The air conditioning system that adopts ice storage is based
on a principle as follow: operate the compressor at a selected time
period (such as off peak load or half peak load period) to form ice
from the chill water and store the cooling energy of the compressor
in the form of ice; during the peak load period in day time and the
chill water (cooling air) is needed, but operation of the chill
water device is undesirable (peak load time period), melt the ice
to absorb the heat of the chill water at a constant temperature to
cool the chill water; thus power consumption of air conditioning at
the peak load period in the day time can be transferred to the
night time. Namely melting of the ice can absorb the heat of the
high temperature chill water to cool the chill water so that the
power consumption of air conditioning at the peak load period in
the day time can be transferred to the night time.
[0004] Refer to FIG. 1 for the refrigerant system of a conventional
ice storage air conditioning system. It operates in such a way:
when the returned chill water in an air conditioner (indoor device)
is at a temperature above a set value of a return water temperature
sensor, the system activates a compressor 11 to operate; the
refrigerant is conveyed through an gas duct 19 to the compressor 11
and compressed to become an over-heated refrigerant in a gas phase
at a high pressure and high temperature; then the refrigerant
enters a condenser 12 to disperse heat to become cooling
refrigerant in a liquid phase at a high pressure but a normal
temperature; the refrigerant flows through a liquid duct 13 to a
heat exchanger 14 to become a subcooling refrigerant in the liquid
phase at a high pressure and a low temperature; through throttling
of an expansion valve 15 the pressure of the refrigerant drops to
become a saturated and mist type refrigerant in liquid and gas
phases at a low pressure and low temperature; then the refrigerant
enters an evaporator 16 to be vaporized to absorb a great amount of
latent heat to be chilled; cooling air is sent out through an air
conditioner 17 to an air conditioning room; the refrigerant absorbs
heat to become low pressure at the normal temperature and flows to
an ice storage refrigerant loop 18 of an ice storage tank to store
ice for residual refrigerant; the refrigerant flowing through the
ice storage refrigerant loop 18 returns to the compressor 11
through the gas duct 19 to complete a refrigerant circulation
cycle.
[0005] The chill water flowing out of the air conditioner 17 is
sent to a chill water side of the evaporator 16 through a chill
water pump to become chill water at a low temperature (generally at
7.quadrature.) to provide the air conditioner 17 to cool the
heating load in the air conditioning room, thus complete a chill
water circulation cycle.
[0006] The refrigerant has to flow through the evaporator 16 to
enter the ice storage refrigerant loop 18 whether in the condition
of a low cooling room or high cooling room. Hence the heat energy
of all the refrigerant has to be transferred through the evaporator
16 to enter the ice storage refrigerant loop 18 no mater how much
the refrigerant actually needed in the evaporator 16. It greatly
reduces the ice storage efficiency in the condition of low cooling
room.
[0007] Moreover, the ice storage constant temperature air
conditioning system now on the market adopts an evaporator which
discharges the condensate being generated. Hence water has to be
replenished to the ice storage apparatus to achieve the ice storage
effect. It is a waste of water in the air conditioning system.
SUMMARY OF THE INVENTION
[0008] Therefore the primary object of the present invention is to
provide an ice storage constant temperature air conditioning system
that adopts divided refrigerant. It has a refrigerant divider in a
refrigerant system ahead an evaporator. The refrigerant divider
controls flow amount and direction of the refrigerant. Flow of the
refrigerant is divided into two ducts. One duct is connected to the
evaporator and other duct is connected to an ice storage
refrigerant loop of an ice storage tank. Hence the refrigerant can
totally flow in the ice storage tank to store ice or the evaporator
to melt the ice for air conditioning use, or partially flow to the
ice storage tank and the evaporator. Thereby the system of the
invention can divide and distribute the refrigerant according to
the load of the air conditioning room to transfer heat energy. It
can save energy and achieve an optimum air conditioning operation
efficiency at a constant temperature.
[0009] Another object of the invention is to provide a condensate
collection tray under the evaporator to cycle the heat of the low
temperature condensate generated during operation of the air
conditioning. It also can automatically replenish the chill water
in the ice storage tank. Moreover, during storing ice or melting
ice the refrigerant at the outlet of the condenser is cooled to
become a subcooling liquid refrigerant to enhance refrigeration
effect.
[0010] The ice storage constant temperature air conditioning system
that adopts divided refrigerant according to the invention includes
a compressor to compress refrigerant to become an over-heated
refrigerant in a gas phase at a high pressure and high temperature,
a condenser to receive the over-heated refrigerant in the gas phase
and cool the refrigerant to become a liquid refrigerant at a high
pressure and a normal temperature, a refrigerant divider to receive
the cooling liquid refrigerant through a liquid duct and divide
automatically the cooling liquid refrigerant into a first duct and
a second duct. The first duct has a heat exchanger to transform the
cooling liquid refrigerant to a subcooling liquid refrigerant at a
high pressure and low temperature, then the subcooling liquid
refrigerant flows to an air conditioning expansion valve to be
expanded and become a saturated and mist type refrigerant in liquid
and gas phases to enter an evaporator which absorbs a great amount
of latent heat through evaporation to generate cooling effect;
residual refrigerant flows to an ice storage refrigerant loop to
generate refrigeration and store ice. The second duct is connected
to the ice storage refrigerant loop through an ice storage
expansion valve which expands the refrigerant to absorb a great
amount of latent heat to store the ice. The refrigerant in the ice
storage refrigerant loop finally returns to the compressor through
a gas duct to complete one refrigerant circulation cycle. Thus the
refrigerant can fully flow into the ice storage tank to store the
ice or fully enter the evaporator to melt the ice to generate air
conditioning, or partially flow to the ice storage tank and the
evaporator.
[0011] The foregoing, as well as additional objects, features and
advantages of the invention will be more readily apparent from the
following detailed description, which proceeds with reference to
the accompanying drawings. The embodiments being discussed serve
only for illustrative purpose and are not the limitation of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic view of the refrigerant system of a
conventional ice storage air conditioning.
[0013] FIG. 2 is a schematic view of the refrigerant system of the
ice storage air conditioning of the invention.
[0014] FIG. 3 is a schematic view of the apparatus of the
invention.
[0015] FIG. 4 is a schematic view of the invention for distributing
a low load of a cooling room and an ice storage refrigeration load
in the condition of a low cooling room.
[0016] FIG. 5 is a schematic view of the invention for distributing
a high load of a cooling room and an ice melting load in the
condition of a high cooling room.
[0017] FIG. 6 is a Mollier chart of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Please refer to FIG. 2 for a refrigerant system of an ice
storage air conditioning of the invention. When in use and the
temperature of returned chill water of an air conditioner (indoor
device) is above a set value of a return water temperature sensor,
the system activates a compressor 21 to operate, and refrigerant in
a gas duct 29 is compressed by the compressor 21 to become
over-heated refrigerant in a gas phase at a high pressure and high
temperature. The over-heated gas refrigerant enters a condenser 22
to disperse heat to become a liquid phase refrigerant at a high
pressure and normal temperature. The liquid refrigerant at the high
pressure and normal temperature flows in a refrigerant divider 25
through a liquid duct 23 that divides the refrigerant into two
branched flows. One branched flow is expanded and throttled to
become a saturated and mist type refrigerant at a low pressure and
low temperature to flow through a first duct 251 and a heat
exchanger 24 on the first duct to become a subcooling liquid
refrigerant at a high pressure and low temperature, then is
expanded through an air conditioning expansion valve 253 to become
a saturated and mist type liquid and gas refrigerant to enter an
evaporator 26 to be vaporized to absorb a great amount of latent
heat in the air of an air conditioning room to generate
refrigeration. Cooling air is delivered through an air conditioner
27 to the air conditioning room. The refrigerant absorbs heat to
become low pressure at the normal temperature, and flows to an ice
storage refrigerant loop 28 of an ice storage tank to store ice
through residual refrigerant. Another branched flow of the cooling
liquid refrigerant flows to a second duct 252 to be expanded
through an ice storage expansion valve 254 and delivered to the ice
storage refrigerant loop 28 to store the ice. Finally the
refrigerant in the ice storage refrigerant loop 28 that has
finished the ice storage operation returns to the compressor 21
through the gas duct 29 to complete one refrigerant circulation
cycle of an air conditioning system.
[0019] In the event that the heat exchange medium of the evaporator
26 is chill water, the returned chill water flowing out of the air
conditioner 27 is delivered to a chill water side of the evaporator
26 through a chill water pump to form chill water of a low
temperature (generally at 7.quadrature.) to supply the chill water
required in the air conditioner 27 to produce air conditioning, and
cool the heat load in the air conditioning room to complete one
chill water circulation cycle.
[0020] Refer to FIG. 3 for the apparatus of the invention. To
facilitate utilization of the condensate of the ice storage air
conditioning of the invention, the apparatus includes an outdoor
device 30 which contains the compressor 21 and the condenser 22, an
indoor device 40 which is connected to the outdoor device 30
through the gas duct 29 and the liquid duct 23. The indoor device
40 includes an ice storage tank 50 to maintain temperature. The ice
storage tank 50 has the ice storage refrigerant loop 28 at the
upper half portion and the heat exchanger 24 at the lower half
portion. The evaporator 26 is located above the ice storage tank
50. The air conditioner 27 is located above the evaporator 26.
There is an air outlet 271 of the indoor device 40 on an upper side
of the air conditioner 27 to deliver cooling air to the air
conditioning room. Below the evaporator 26 there is a condensate
collection tray 51 to recycle the low temperature condensate
generated during operation of the air conditioning. The collected
water of the condensate collection tray 51 is channeled to the ice
storage tank 50 to automatically replenish the chill water. Such a
design does not require replenishing additional water to the chill
water circulation cycle during operation of the air conditioning.
Moreover, the low temperature condensate can cool the refrigerant
at the outlet of the condenser 22 to become the subcooling liquid
refrigerant during ice storing or melting to enhance refrigeration
effect.
[0021] The refrigerant divider 25 divides the refrigerant according
to different conditions of the air conditioning room and
distributes the refrigerant to the first duct 251 and the second
duct 252 according to the following conditions:
[0022] 1. No load in the cooling room: Q.sub.0=Q.sub.2;
[0023] 2. Low load in the cooling room:
Q.sub.0=Q.sub.1+Q.sub.2;
[0024] 3. Full load in the cooling room: Q.sub.0=Q.sub.1;
[0025] 4. High load in the cooling room: Q.sub.0=Q.sub.1+ice
storage cooling energy.
[0026] Where Q.sub.0 is total refrigerant amount; Q.sub.1 is the
refrigerant amount in the first duct 251, namely the refrigerant
amount flows first to the evaporator 26; Q.sub.2 is the refrigerant
amount in the second duct 252, namely the refrigerant amount
directly flows to the ice storage refrigerant loop 28.
[0027] 1. During the condition of no load in the cooling room, the
refrigerant divider 25 closes the first duct 251 to allow all the
refrigerant to directly flow through the second duct 252 to the ice
storage refrigerant loop 28 so that all the refrigerant serves to
store energy in ice. The stored energy can be used in the condition
of high load in the cooling room later.
[0028] 2. During the condition of low load in the cooling room, a
sensor sends a signal of a measured temperature to the refrigerant
divider 25 which controls the ratio of the refrigerant amount
Q.sub.1 in the first duct 251 and the refrigerant amount Q.sub.2 in
the second duct 252 according to actual requirement so that the
refrigerant amount Q.sub.1 in the first duct 251 can be changed to
feed into the evaporator 26 according to alteration of the room
temperature. The rest of the total refrigerant Q.sub.0 is
distributed to the second duct 252. Referring to FIG. 4 for
distribution of a low air-conditioning load and an ice storage
refrigeration load in the condition of a low cooling room. The flow
amount of the refrigerant is divided into two portions. One portion
flows to the evaporator 26 to meet the need of the low load in the
cooling room, and other portion directly flows to the ice storage
refrigerant loop 28 to generate refrigeration to store ice. The
total load of the total refrigerant Q.sub.0 can reach 100% full
load condition.
[0029] 3. During the condition of full load in the cooling room,
the second duct 252 is closed by the refrigerant divider 25. All
the refrigerant goes through a phase change and flows directly to
the evaporator 26 through the first duct 251 and is consumed there.
Hence all the refrigerant Q.sub.0 is used to support the load of
the cooling room.
[0030] 4. During the condition of high load in the cooling room,
the refrigerant divider 25 sends all the refrigerant to the
evaporator 26, but the temperature detected by the sensor does not
yet reach a set temperature, namely the refrigeration power
provided by all the refrigerant Q.sub.0 is not adequate, the ice
storage tank 50 melts the ice through the heat exchanger 24 so that
the cooling energy of the stored ice generated by the ice storage
refrigerant loop 28 during the conditions of the previous no load
in the cooling room and low load in the cooling room is released to
provide the energy according to the loading requirement of the
cooling room, thereby to enable the cooling room to reach the
required temperature. Refer to FIG. 5 for load distribution of a
high load cooling room and an ice melting load in the condition of
a high cooling room. The refrigerant flow is same as for the
condition of the fully loaded cooling room. The refrigerant divider
25 closes the second duct 252, and all the phased changed
refrigerant is sent to the evaporator 26 so that the total
refrigerant amount Q.sub.0 is to meet the loading requirement of
the cooling room. At this moment the energy provided by the
compressor 21 cannot meet the loading requirement of the high load
in the cooling room. The cooling energy of the ice storage
generated during the conditions of no load in the cooling room and
low load in the cooling room is transformed through the heat
exchanger 24 to cool the refrigerant to become the subcooling
refrigerant. The temperature of the liquid refrigerant is lowered
to increase subcooling of the refrigerant. As a result the
circulation amount of the refrigerant can be increased and the
cooling capability of can enhanced by about 30%.
[0031] Refer to FIG. 6 for a Mollier chart of the invention. It
indicates the efficacy analysis of the invention related to the
measured pressure and temperature of the main elements, and
compares with the conventional ice storage air conditioning system
without refrigerant division, where:
[0032] h2-h3'=original cooling effect;
[0033] h3'-h3=low temperature condensate+enhanced subcooling effect
resulting from ice melting; the cooling effect of the
invention=(h2-h3')+(h3'-h3);
[0034] h1-h4'=original refrigeration effect;
[0035] h4'-h4=the refrigeration effect provided by the subcooling
refrigerant;
[0036] The refrigeration effect of the
invention=(h1-h4')+(h4'-h4).
[0037] As a conclusion, the refrigerant division and heat
reclaiming from condensate recycling of the invention allow the
refrigerant to fully flow to the ice storage tank to store ice or
fully flow to the evaporator to melt the ice to provide air
conditioning, or partially enter the ice storage and the
evaporator. The system can divide and distribute the refrigerant
according to the loading condition of the air conditioning room to
transfer energy. It can save energy and achieve an optimum cooling
effect for air conditioning at a constant temperature.
[0038] While the preferred embodiments of the invention have been
set forth for the purpose of disclosure, modifications of the
disclosed embodiments of the invention as well as other embodiments
thereof may occur to those skilled in the art. Accordingly, the
appended claims are intended to cover all embodiments which do not
depart from the spirit and scope of the invention.
* * * * *