U.S. patent application number 14/020845 was filed with the patent office on 2015-03-12 for solar cooling system integrated in building envelope.
The applicant listed for this patent is Shishir Gupta, Sumit Sharma, Rahul Singh. Invention is credited to Shishir Gupta, Sumit Sharma, Rahul Singh.
Application Number | 20150068239 14/020845 |
Document ID | / |
Family ID | 52624190 |
Filed Date | 2015-03-12 |
United States Patent
Application |
20150068239 |
Kind Code |
A1 |
Gupta; Shishir ; et
al. |
March 12, 2015 |
SOLAR COOLING SYSTEM INTEGRATED IN BUILDING ENVELOPE
Abstract
The present invention provides a solar cooling system which is
so small in size so that it can be used as a building material. The
design based on absorption and adsorption refrigeration cycle has
been developed to fulfill this objective. The design has been
developed such that the system is completely independent and does
not require any other source of energy apart from solar heat. Also
an effort is made to design the system so that the cooling capacity
is automatically increased or decreased based on available solar
heat energy.
Inventors: |
Gupta; Shishir; (New Delhi,
IN) ; Sharma; Sumit; (Beaverton, OR) ; Singh;
Rahul; (New Delhi, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gupta; Shishir
Sharma; Sumit
Singh; Rahul |
New Delhi
Beaverton
New Delhi |
OR |
IN
US
IN |
|
|
Family ID: |
52624190 |
Appl. No.: |
14/020845 |
Filed: |
September 8, 2013 |
Current U.S.
Class: |
62/235.1 |
Current CPC
Class: |
F25B 39/00 20130101;
Y02B 30/64 20130101; Y02B 30/62 20130101; F25B 35/00 20130101; Y02B
30/00 20130101; F25B 15/14 20130101; F25B 15/00 20130101; Y02B
10/24 20130101; Y02A 30/272 20180101; Y02B 10/20 20130101; Y02A
30/277 20180101; F24S 20/69 20180501; F25B 27/007 20130101; F25B
2500/17 20130101; Y02A 30/27 20180101; Y02A 30/278 20180101 |
Class at
Publication: |
62/235.1 |
International
Class: |
F25B 27/00 20060101
F25B027/00 |
Claims
1. a solar cooling system of miniature size in form of a tile or
brick so that it can be used as a building material;
2. an absorption based solar cooling system which meets the
requirement of claim (1);
3. an adsorption based solar cooling system which meets the
requirement of claim (1);
4. an absorber-based cooling system n claim (1) which uses a high
density liquid head to maintain pressure difference between the
absorber and the generator chambers instead of a mechanical
pump.
5. a solar cooling system of claim (1) with variable capacity and
it changes capacity with increase or decrease in available solar
energy;
6. an absorption or adsorption based cooling system of claims (2)
and (3) in which the refrigerant is cooled in condenser then it is
circulated in absorber/adsorber chamber to cool down the
absorber/adsorber, then it is again cooled down to close to ambient
condition using a second condenser before discharging the
refrigerant inside the evaporator chamber;
7. an absorption cooling system of claim (2) which uses reverse
osmosis membrane to transport refrigerant;
8. an absorption cooling system of claim (2) which uses capillaries
to transport the absorber and refrigerant;
9. an adsorption cooling system of claim (3) which comprises of a
rotating adsorber to convert batch process of adsorption cycle in
to a continuous cycle:
Description
REFERENCES CITED
US Patent Numbers:
[0089] [0001] U.S. Pat. No. 8,479,529 [0002] U.S. Pat. No.
8,353,170 [0003] U.S. Pat. No. 8,006,515 [0004] U.S. Pat. No.
5,181,387 [0005] U.S. Pat. No. 4,987,748 [0006] U.S. Pat. No.
4,903,503 [0007] U.S. Pat. No. 7,918,095 [0008] U.S. Pat. No.
7,762,103 [0009] U.S. Pat. No. 7,257,951 [0010] U.S. Pat. No.
6,397,625 [0011] U.S. Pat. No. 6,116,039 [0012] U.S. Pat. No.
4,881,376
FIELD OF THE INVENTION
[0013] The present invention relates a solar powered cooling system
used in HVAC (Heat Ventilation and Air Conditioning) system of
buildings. More particularly, the present invention relates to
absorption or adsorption based refrigeration system integrated in
the outside envelope of any construction to cool the inside using
solar energy. The solar cooling system is made compact so that it
can be easily integrated in the building envelope.
BACKGROUND OF THE INVENTION
[0014] The absorption or adsorption based cooling system uses heat
to provide air-conditioning. These are popular air-conditioning
systems, wherever waste heat is available (like in process plants,
power plants etc.). Absorption based chillers mostly use Lithium
Bromide (LiBr)-Water system or Water-Ammonia as
absorber-refrigerant for absorption cycle. Adsorption based
chillers usually use Silica Gel-Water or Zeolite-Water as
adsorber-refrigerant pair. The adsorption/absorption cycle (FIG. 1)
is similar to a vapor compression cycle, but instead of a
mechanical compressor, the compression of the refrigerant vapor is
achieved via adsorption/absorption process. FIG. 1 illustrates the
working of an adsorption/absorption cooling cycle. The refrigerant
enters the evaporator as a saturated liquid. The pressure of the
evaporator chamber is such that the corresponding saturation
temperature of the refrigerant is below the temperature of the
region to be cooled. Let the region to be cooled be termed as
region C. Inside the evaporator, the refrigerant evaporates. The
latent heat of vaporization is extracted from the region C. The
extraction of heat of vaporization causes the region C to cool
down. After evaporation, the refrigerant converts into saturated or
super-heated vapor. In case of absorption cooling system, the
refrigerant is absorbed in a substance which has high affinity to
absorb water (for example, a concentrated solution of LiBr). The
substance is called an absorbent. The absorbent chamber is
connected to a Generator chamber. In the Generator chamber, the
absorbent is heated from a heat source. The increase in temperature
of the absorbent leads to release of the refrigerant. The
refrigerant is released from the absorbent in the vapor phase at
higher pressure than the evaporator. The refrigerant then goes to a
condenser wherein it is condensed to liquid state by removal of
heat. The refrigerant comes out of the condenser as a saturated
liquid. The refrigerant then passes through a throttle valve, which
leads to a sudden decrease in the pressure of the refrigerant.
Because of this sudden drop in the pressure, a small amount of
refrigerant evaporates, and the remaining refrigerant cools down to
the saturation temperature associated with the low pressure in the
evaporator. In an adsorption cooling cycle, instead of an
absorption chamber, the refrigerant is adsorbed in an adsorber. In
the Generator chamber, the adsorber is regenerated by heat, which
releases the refrigerant. In FIG. 1, the Desorption/Generator (D)
is the energy consuming chamber and it consumes heat energy instead
of electric energy in compressors. The Condenser (Q.sub.out) and
Absorber/Adsorber (A) reject heat to environment. The Evaporator
(Q.sub.in) takes the heat from the occupied space. The coefficient
of performance (COP) of the system is defined as:
COP=Q.sub.in/Generator(D)heat consumed
[0015] In FIG. 1, [0016] Q.sub.in=Heat absorbed by evaporator from
the occupied space, [0017] Absorber=Absorber or Adsorber chamber
[0018] Desorber=Generator chamber taking heat as energy input and
separating refrigerant from adsorber/absorber [0019] Pump=Pump for
flow of absorber (Not required in adsorption cycle)
[0020] The simplified process of absorption is explained in FIG. 2.
The absorber has affinity toward the refrigerant and hence the
refrigerant in the evaporator chamber evaporates and gets absorbed
in the absorber chamber. The process of evaporation cools down the
evaporator chamber. In order to regenerate the absorber and the
refrigerant, heat is provided to the absorber chamber, due to which
the refrigerant gets separated from the absorber. This refrigerant
is then replenished in the evaporator chamber using an expansion
valve and then the process is repeated.
[0021] The working of adsorption cycle is similar to absorption
cycle, the only difference being that instead of liquid absorber,
solid adsorber is used to evaporate refrigerant. The capacity of
absorption chillers is available in various sizes varying from 10
KW to 10,000 KW. Numerous conventional chiller companies like York,
Trane, Johnson-Control, Thermax etc. have absorption and adsorption
chillers in their product range. These chillers typically use waste
heat available in process plants and power plants. There have been
efforts to power these chillers using solar energy. There have been
recent innovations related to reflectors to concentrate the solar
heat to attain the required temperature and energy to power these
chillers. However the usage of such chillers using solar energy is
still not cost effective and there have been very limited
installations of such systems, especially in residential
buildings.
OBJECTS OF THE INVENTION
[0022] The main object of the present invention is to provide a
miniature version of absorption and adsorption cooling system so
that it can be used as a building material.
[0023] Another object of the present invention is to design a
passive system which can run solely on the solar energy.
[0024] Yet another object of the present invention is to design
building material which can be retrofitted to existing
construction, providing cooling using solar energy.
[0025] Yet another object of the present invention is to design the
system such that its cooling capacity increases with increase in
available solar energy, hence it cools less when solar energy is
less and cools more when solar energy is more.
DETAILED DESCRIPTION OF THE INVENTION
[0026] FIG. 3 is a schematic drawing of the 1.sup.st embodiment of
the refrigeration system. 301 is the evaporation chamber which is
in thermal contact with the region to be cooled (denoted by region
C). Let the target temperature of region C be denoted by T.sub.c.
The temperature in chamber 301, denoted by T.sub.e should be such
that T.sub.e<T.sub.c. From the thermodynamic properties of the
refrigerant, the pressure inside the chamber 301, denoted by
P.sub.e is determined so that T.sub.e is the saturation temperature
of the refrigerant in chamber 301. Chamber 301 absorbs heat from
region C because of thermal contact between then causing the
refrigerant to evaporate. On evaporation, refrigerant absorbs heat.
Chamber 302 is the absorber chamber containing concentrated
absorber, which is capable of absorbing refrigerant vapour.
Presence of concentrated absorber also promotes evaporation of the
refrigerant in chamber 301. Evaporated refrigerant from chamber 301
gets absorbed to the absorber in chamber 302. Absorption of
refrigerant is accompanied by release of heat. This heat is removed
via cooling tubes 308. In one embodiment, the fluid in cooling
tubes 308 is cooled via capillary evaporation. The diluted absorber
is pumped from chamber 302 to chamber 303 using a micro-pump 309.
Chamber 303 is the generator chamber. Dilute absorber in chamber
303 is heated using a heat source. In the embodiment shown in FIG.
3, the heat source is sun's radiation. In another embodiment, the
heat source can be waste heat from an internal combustion engine,
or waste heat from a chemical or nuclear reaction. The pressure in
chamber 303, denoted by P.sub.g is higher than P.sub.e. Upon
getting heated, refrigerant is released from the absorber and
concentrated absorber flows back to chamber 302. The tube bringing
the absorber from chamber 303 to chamber 302 is connected to tube
310, which is filled with a high density liquid, such as mercury to
ensure the pressure difference between the chamber 302 and chamber
303 is maintained. The desorbed refrigerant in vapour state in
chamber 303 flows to chamber 304, which is called the condenser
chamber. In chamber 304, the refrigerant is cooled and condensed.
In one embodiment of the invention, cooling in chamber 304 is
achieved via capillary evaporation of cooling fluid flowing in
cooling tubes 307. The condensed refrigerant in chamber 304 at
pressure P.sub.g passes through a throttle valve 305 to chamber
301, which is at lower pressure, P.sub.e. Upon sudden decrease in
pressure, a small fraction of the refrigerant evaporates, thereby
cooling the remaining refrigerant to the temperature T.sub.e in the
evaporation chamber 301. From chamber 301, the above described
cycle continues. Different chambers of the system are thermally
insulated from each other using insulating material 306
(represented in FIG. 4 by broad lines). The chamber 310 in FIG. 4
also acts like an insulating region.
[0027] FIG. 4 shows another design of the invention. The basic
process cycle of this design is the same as the design in FIG. 3.
Chamber 101 is the evaporation chamber, chamber 102 is the
absorption chamber, chamber 103 is the generator chamber, chamber
104 is the condenser chamber, 105 is the throttle valve, 106 is
insulation material which is represented in the diagram as thick
lines. 107 and 108 are cooling tubes for chamber 102 and chamber
104 respectively. In this design, a reverse osmosis (RO) membrane
109 separates the absorber chamber 102 and the generator chamber
103. The RO membrane allows only the refrigerant to pass through
it. When the unit is not in operation, the refrigerant in chamber
103 remains in equilibrium with the refrigerant in chamber 102.
That is, the high pressure P.sub.g in chamber 103 plus the fluid
pressure due to gravity is balanced by the osmotic pressure plus
P.sub.e across the RO membrane 109 because of the lower
concentration of absorbent in chamber 102. Contrary to the
traditional absorption based refrigerators, in this design the
absorption chamber 102 is maintained at lower absorbent
concentration than the generator chamber 103 in order to trap
overhead sun rays. During normal operation of the unit, as
refrigerant is absorbed in chamber 102, the pressure differential
will develop across the RO membrane 109 because of which the
refrigerant will flow into chamber 103. In chamber 103, using heat,
refrigerant is separated from the absorbent. The remaining
functioning of this design is similar to one described in FIG. 3.
The working conditions (temperature, pressure) of different
chambers is similar to the design in FIG. 3.
[0028] FIG. 5 shows another design of the invention. The basic
process cycle of this design is the same as the design in FIG. 3.
Chamber 201 is the evaporation chamber, chamber 202 is the
absorption chamber, chamber 203 is the generator chamber, chamber
204 is the condenser chamber, 205 is the throttle valve, 206 is
insulation material which is represented in the diagram as thick
lines. 207 and 208 are cooling tubes for chamber 202 and chamber
204 respectively. In this design, a reverse osmosis (RO) membrane
209 separates the absorber chamber 202 and the generator chamber
203. The RO membrane allows only the refrigerant to pass through
it. Similar to the design in FIG. 3, the absorber in chamber 202 is
at slightly lower concentration than in chamber 203 in order to
balance the higher pressure in chamber 203 (P.sub.g) with osmotic
pressure.
[0029] The design of the system is made such that miniature version
of vapor absorption or adsorption cycle is packed in to a small
chamber. The various possible embodiments of this design are shown
in FIGS. 1, 2(a), 2(b), 2(c), 3(a), 3(b) and 4.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0030] In the drawings accompanying the specification,
[0031] FIG. 1 shows the cycle diagram for absorption or adsorption
refrigeration system used in this invention.
[0032] FIG. 2 shows the mechanism of absorption/adsorption and
regeneration process used in this invention.
[0033] FIG. 3 shows the 1.sup.st embodiment of design and
arrangement of absorption based system proposed in this
invention.
[0034] FIG. 4 shows the 2.sup.nd embodiment of design and
arrangement of absorption based system proposed in this
invention.
[0035] FIG. 5 shows the 3.sup.rd embodiment of design and
arrangement of absorption based system proposed in this
invention.
[0036] Although the description of this invention has been given
with reference to a particular embodiment, it is not to be
construed in a limiting sense. Many variations and modifications
will now occur to those skilled in the art. For a definition of the
invention reference is made to the appended claims.
* * * * *