WO2010038236A2 - An absorption refrigeration system and a process for refrigeration utilizing the same - Google Patents
An absorption refrigeration system and a process for refrigeration utilizing the same Download PDFInfo
- Publication number
- WO2010038236A2 WO2010038236A2 PCT/IN2009/000364 IN2009000364W WO2010038236A2 WO 2010038236 A2 WO2010038236 A2 WO 2010038236A2 IN 2009000364 W IN2009000364 W IN 2009000364W WO 2010038236 A2 WO2010038236 A2 WO 2010038236A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- heat exchanger
- evaporator
- refrigerant
- bleed
- loop
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B15/00—Sorption machines, plants or systems, operating continuously, e.g. absorption type
- F25B15/006—Sorption machines, plants or systems, operating continuously, e.g. absorption type with cascade operation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/62—Absorption based systems
Abstract
An absorption refrigeration system and a process for producing refrigeration using the system, wherein the system comprises two thermally coupled loops - each loop comprising a working fluid, a reboiler, a distillation column, a condenser, an evaporator and an absorber, a bleed heat exchanger, a refrigerant heat exchanger and a solution heat exchanger; wherein each of the first and second reboiler is provided with a low grade heat and providing at least one pressure regulating means selected from at least one valve, a plurality of pressure pumps and/or an inert component in the absorption refrigeration system.
Description
AN ABSORPTION REFRIGERATION SYSTEM AND A PROCESS FOR REFRIGERATION UTILIZING THE SAME
FIELD OF INVENTION
The present invention, in general, relates to an Absorption Refrigeration system using low grade heat source and a refrigeration process using the absorption refrigeration system.
BACKGROUND AND PRIOR ART
Absorption Refrigeration is a heat operated refrigeration cycle. Currently, waste heat or low grade heat from industrial processes is normally rejected or wasted into the environment. With increasing pressure on global energy sources, the industry is moving towards using alternative energy and improving energy efficiency. The waste heat available in the industries can be utilized for producing useful refrigeration by heat-operated absorption refrigeration cycles.
In order to lower fuel costs, it is also desirable to improve energy utilization of these wasted sources of low grade heat. These sources include heat provided as by-product of a chemical reaction or available as heat losses from boilers, drying equipment, chemical reactors, or the like. It has been suggested that such waste heat be used instead of higher grade energy sources to provide the energy requirements for absorption refrigeration cycle for commercial and industrial facilities.
However, much of the available waste heat from the above-mentioned sources is at a temperature too low to be readily used in absorption refrigeration systems. For example, a simple absorption cycle system provides no cooling from heat sources having a temperature of 80° C or below, if cooling is required at 0° C. However, many industrial process waste heat streams are available at only 65°C - 85° C.
US Patent 6397625 discloses an absorption refrigeration system working on Platen- Munters principle. It further relates to the use of a bubble pump for maintaining the liquid circulation in the absorption refrigeration system. The disadvantage of using the bubble pump is that it is passive and there is no control over the liquid flow.
Indian Patent 483/MUM/2006 discloses a single cycle refrigeration system which utilizes a low grade waste heat to drive a combustion turbine inlet air cooling system using ammonia absorption refrigeration plant. Further, the patent describes two stages of desorption and absorption. However, this system specifically relates only to the cooling of the combustion turbine inlet air and this is achieved using only ammonia- water in the absorption refrigeration cycle.
US Patent 5572884 relates to dual cycle system where heat from absorber or condenser is given to reboiler of second loop. According to this patent, said absorber or condenser operates at a temperature above the reboiler temperature of the second cycle. The patent also discloses the use of combination of a refrigerant heat exchanger and solution heat exchanger in the system.
However, there is still underutilized heat in the refrigeration cycle which can be more efficiently used for producing refrigeration and making the refrigeration cycle more efficient.
The present inventors in a publication titled "Performance evaluation of Ammonia Absorption Refrigeration cycle based on exergetic coefficient of performance" (Int. J. Exergy. Vol. 4, No. 1, Pages 19 — 37 (2007)), have disclosed the optimized conditions for improving the efficiency of Single cycle Absorption Refrigeration systems.
In a second publication titled "Simulation of dual Ammonia Absorption Refrigeration cycle for effective utilization of low temperature heat source" (Int. J. Exergy. Vol. 4., No. 3, Pages 253 - 270 (2007)), the present inventors disclosed the utilization of low temperature heat source for producing refrigeration, using a condenser-evaporator coupled dual cycle absorption refrigeration system.
Accordingly, the need exists for an absorption refrigeration cycle system which can utilize any low grade heat available from industrial process streams as well as underutilized energy in the refrigeration cycle and enhance the thermodynamic efficiency of the absorption refrigeration system.
SUMMARY OF THE INVENTION
The present invention is directed at an absorption refrigeration system comprising: a. a first loop comprising a first working fluid, a first reboiler, a first distillation column, a first condenser, a first evaporator and a first absorber, all operatively connected together, a first bleed heat exchanger for cooling a condensed product from the first condenser using a refrigerant bleed from the first evaporator, a first refrigerant heat exchanger for cooling a condensed product from the bleed heat exchanger using a refrigerant vapor from the first evaporator, and a first solution heat exchanger for heating an absorbed product from the first absorber using a bottom product from the first distillation column; and, b. a second loop in thermal connection with the first loop, the second loop comprising a second working fluid, a second reboiler, a second distillation column, a second condenser, a second evaporator and a second absorber, all operatively connected together, a second bleed heat exchanger for cooling a condensed product from the second condenser using a refrigerant bleed from the second evaporator, a second refrigerant heat exchanger for cooling a condensed product from the bleed heat exchanger using a refrigerant vapor from the second evaporator, and a second solution heat exchanger for heating an absorbed product from the second absorber using a bottom product from the second distillation column, wherein each of the first and second reboiler is provided with a low grade heat and c. at least one pressure regulating means selected from at least one valve, a plurality of pressure pumps and/or an inert component..
In an alternate embodiment, the invention comprises a refrigeration process in an absorption refrigeration system comprising a first loop and a second loop, the improvement in the process comprising steps of: a. thermally coupling the first loop and the second loop, wherein the first loop comprises a first working fluid, a first distillation column, a first reboiler, a first condenser, a first absorber, a first evaporator, a first bleed heat exchanger, a first refrigerant heat exchanger and a first solution heat exchanger, all operatively connected together, and the second loop comprises a second working fluid, a second distillation column, a second reboiler, a second condenser, a second absorber, a second evaporator, a second bleed heat exchanger, a second refrigerant heat exchanger and a second solution heat exchanger, all operatively connected together;
b. providing a low grade heat to each of the first and second reboiler; c. cooling the condensed product, from each condenser, with the refrigerant bleed from the corresponding evaporator, in each of the first and second bleed heat exchangers; d. cooling the cooled condensed product, from each bleed heat exchanger, with the refrigerant vapor from the corresponding evaporator, in each of the first and second refrigerant heat exchangers; e. heating the absorbed product, from each absorber, with a bottom product from corresponding distillation column, in each of the first and second solution heat exchangers and f. providing at least one pressure regulating means selected from at least one valve, a plurality of pressure pumps and/or an inert component in the absorption refrigeration system.
The present invention thus provides a new multi loop dual cycle absorption refrigeration system and method of using the same for producing refrigeration which utilizes low grade heat.
The absorption refrigeration system and process for producing refrigeration using the same gives a very high coefficient of performance as well as High Exergetic coefficient of performance.
BRIEF DESCRIPTION OF THE INVENTION
For a more complete understanding of the invention, reference should now be made to the embodiment illustrated in greater detail in the accompanying drawing and described below by way of an example of the invention.
FIG. l is a schematic diagram of an Ammonia- Ammonia dual cycle/loop absorption refrigeration machine in accordance with an embodiment of the invention.
It is to be understood that the drawing is not to scale and is schematic in nature. In certain instances details, which are not necessary for an understanding of the present invention or which renders other details difficult to perceive may be omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.
DETAILED DESCRIPTION OF THE INVENTION
For a better understanding of the present invention, reference will be made to the following detailed description of the invention which is to be read in association with the accompanying drawings.
In describing the embodiment of the invention which is illustrated in the drawings, specific terminology is resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.
Although a preferred embodiment of the invention has been described herein, it is understood that various changes and modifications in the illustrated and described structure can be affected without departure from the basic principles that underlie the invention. Changes and modifications of this type are therefore deemed to be circumscribed by the spirit and scope of the invention, except as the same may be necessarily modified by the appended claims or reasonable equivalents thereof.
The present invention relates to an absorption refrigeration system comprising two or more loops. However, for explanatory purposes, the system will be described with specific reference to a double loop system.
The term "low grade heat" may be defined as one where the ratio R defined below is less than or equal to 2.5:
R= (Temperature of low grade heat- Temperature of heat sink) ÷ (Temperature of heat sink - Refrigeration temperature)
Temperature of Heat sink is the cooling water return temperature. Refrigeration temperature refers to the temperature at which refrigeration is produced and depends on the evaporator temperature. Low grade heat is a relative term and heat sources of a wide range of temperatures can be utilized as low grade heat sources.
The term "Coefficient of Performance" (COP) is the parameter used to quantify the performance of vapor absorption refrigeration cycle.
COP = (Refrigeration provided by evaporator) ÷ (heat supplied to reboiler)
The term "Exergetic Coefficient of Performance" (ECOP) is the parameter used to quantify the performance of vapor absorption refrigeration cycle based on quality of low grade heat source, temperature of refrigeration and heat sink temperature.
ECOP = (Refrigeration provided by evaporator converted to equivalent mechanical energy) ÷ (theoretical extractable work for energy input)
In greater detail, the subject invention is directed to an Absorption Refrigeration system using low grade heat and a refrigeration process using the absorption refrigeration system.
FIG. 1 depicts an absorption refrigeration system 100, in accordance with an embodiment. The system 100 has two loops or cycles - a "First loop (102)" and a "Second loop (202)". The first loop (102) comprises a first working fluid (not shown), a first reboiler (104), a first distillation column (106), a first condenser (108), a first evaporator (112) and a first absorber (118), all operatively connected together, a first bleed heat exchanger (114) between the first condenser (108) and the first evaporator (112), a first refrigerant heat exchanger (116) between the bleed heat exchanger (114) and the first evaporator (112), and a first solution heat exchanger (120) between the first absorber (118) and the first distillation column (106) or first reboiler (104). The second loop (202) is in thermal connection with the first loop(102), and the second loop (202) comprises a second working fluid (not shown), a second reboiler (204), a second distillation column (206), a second condenser (208), a second evaporator (212) and a second absorber (218), all operatively connected together, a second bleed heat exchanger (214) between the second condenser (208) and the second evaporator (212), a second refrigerant heat exchanger (216) between the bleed heat exchanger (214) the second evaporator (212), and a second solution heat exchanger (220) between the second absorber (218) and the second distillation column (206). Low grade heat (103) is provided to the first reboiler (104) and a similar low grade heat (203) is provided to the second reboiler (204). The low grade heat source can be any conventionally known waste heat source selected from e.g. waste heat from biogas power generator, heat generated from sunlight using solar hot water generator, industrial waste streams etc and covering
a wide range of temperature. The first loop (102) uses cooling water (137) for the first condenser (108) and cooling water (139) for the first absorber (118). The second loop (202) uses cooling water (239) for the second absorber (218). In this embodiment, the first evaporator (112) cools the second condenser (208). The absorption refrigeration system comprises at least one pressure regulating means selected from at least one valve (110, 210) , a plurality of pressure pumps (122, 124, 222, 224) and/or an inert component.
In an alternate embodiment of this invention the first evaporator (112) can be used to cool the second absorber (218) (embodiment not illustrated). In yet another embodiment, the first evaporator (112) can be used to cool the second condenser (208) and the second absorber (218) (embodiment not illustrated).Thus, the evaporator (112) of the first loop (102) is in a direct, thermal coupling relation with at least one of the second condenser (208) and second absorber (218).
In a particular embodiment, the absorption refrigeration system further comprises one or more additional loops (not illustrated) through coupling either the first or second evaporator with an additional loop condenser or the additional loop absorber.
According to another embodiment, a refrigeration process using the above absorption refrigeration system (100) comprising the first loop (102) and the second loop (202) has been described, wherein the improvement in the process comprises steps of: a. thermally coupling the first loop (102) and the second loop (202), wherein the first loop (102) comprises the first working fluid (not shown), the first reboiler (104), the first distillation column (106), the first condenser (108), the first evaporator (112) and the first absorber (118), the first bleed heat exchanger (114), the first refrigerant heat exchanger (116), the first solution heat exchanger (120), all operatively connected together; and the second loop (202) comprises the second working fluid (not shown), the second reboiler (204), the second distillation column (206), the second condenser (208), the second evaporator (212) and the second absorber (218), the second bleed heat exchanger (214), second refrigerant heat exchanger (216), second solution heat exchanger (220), all operatively connected together; b. providing low grade heat (103, 203) to each of the first (104) and second reboiler (204);
c. cooling condensed product (111, 211), from each of the first (108) and second condenser (208), with the refrigerant bleed (121, 221) from the corresponding evaporators (1 12, 212), in each of the first (114) and second bleed heat exchangers (214); d. cooling condensed product (113, 213), from each of the first (114) and second bleed heat exchangers (214), with the refrigerant vapor (117, 217) from the corresponding evaporators (112, 212), in each of the first (116) and second refrigerant heat exchangers (216); and e. heating absorbed product (129, 229), from each of the first (118) and second absorbers (218), with a bottom product (107, 207) from corresponding distillation columns (106, 206) or product (133, 233) from each of the first (104) and second (204) reboilers, in each of the first (120) and second solution heat exchangers (220) and f. providing at least one pressure regulating means selected from at least one valve (110, 210), a plurality of pressure pumps (122, 222, 124, 224) and/or an inert component in the absorption refrigeration system.
In a particular embodiment, the low grade heat used is such that a ratio of the difference between low grade heat temperature and heat sink temperature to the difference heat sink temperature and refrigeration temperature is less than or equal to 2.5.
More particularly, the process for producing refrigeration using the absorption refrigeration system (100) has been described. The first loop (102) and the second (202) are thermally coupled. The working fluid in each of the first (106) and second distillation column (206), is distilled to produce a distillation product (109, 209) and a bottom product (107, 207) respectively, using the corresponding first (104) and second reboiler (204).
Furthermore, the process comprises providing low grade heat (103, 203) to each of the first (104) and second reboiler (204). The distilled product (109, 209) is condensed in each of the first (108) and second condenser (208) respectively. The condensed product (111 and 211) from the first (108) and second condenser (208) is evaporated in each of the first (112) and second evaporator (212). According to the embodiment, the process comprises cooling the condensed product (111, 211) received from each of the first (108) and second condenser (208), in each of the first (114) and second bleed heat exchanger (214), by the refrigerant bleed (121, 221) from the corresponding first and second evaporators (112 and 212). The above cooling of the condensed product (111, 211) from each of the first (108) and second (208) condenser before transferring to
the corresponding refrigerant heat exchangers (116 and 216) results in heating the respective refrigerant bleeds (121, 221) from each of the first (112) and second (212) evaporators.
According to the embodiment, the process comprises cooling the condensed product (113, 213) from the corresponding first (114) and second bleed heat exchanger (214) using the corresponding refrigerant vapor (117 and 217) from the corresponding first (112) and second evaporator (212), in the corresponding refrigerant heat exchangers (116, 216). The above cooling of the cooled condensed product (113, 213) from each of the first (114) and second (214) bleed heat exchanger results in heating the respective refrigerant vapors (117 and 217) from each of the first (112) and second (212) evaporator. The refrigerant product (125, 225) from each of the first (116) and second (216) refrigerant heat exchanger is transferred to the corresponding first (118) and second (218) absorber. According to the embodiment, the absorbed product (129, 229), from each of the first (118) and second (218) absorber, is heated by the bottom product (107 and 207) from corresponding first (106) and second (206) distillation column or product (133, 233) from each of the first (104) and second (204) reboilers, in the first (120) and second solution heat exchangers (220) respectively. The heating of the absorbed product (129 and 229) from each of the first (118) and second (218) absorber before transferring to the corresponding reboilers (104, 204) or distillation columns (106, 206) results in cooling of the bottom product (107 and 207) from each of the first (106) and second (206) distillation columns which in turn is transferred to the absorbers (118 and 218) respectively.
The cooled condensed product (113) from the first bleed heat exchanger (114) is transferred to the refrigerant heat exchanger (116) where it is further cooled. This pre-cooled product (141) from the refrigerant heat exchanger (116) is passed through a valve (110) to reduce its pressure before reaching the low pressure evaporator (112). Lowering the pressure of the pre-cooled condensed product (141), which is already at a low temperature, lowers its boiling point further so that the low pressure condensed product (115) can be evaporated easily. The coldness or refrigeration of the first evaporator (112) is transferred to at least one of the second condenser (208) and the second absorber. Thus, at least one of the second condenser (208) and second absorber is at a very low temperature as compared to the first condenser (108) and the distilled product (209) coming from the second distillation column (206) is condensed very quickly and efficiently. This condensed product (211) is at a low temperature before it reaches the second bleed heat exchanger (214). Here the condensed product (211) will be cooled before transferring
to the refrigerant heat exchanger (216) where it is further cooled and then pressurized using a valve (210) before being transferring to the evaporator (212). Thus, further refrigeration is produced in the second evaporator (212). The refrigerant vapors (125, 225) from the first (116) and second refrigerant heat exchangers (216) are transferred to the corresponding absorbers (118, 218). The absorbed vapor (127, 227) is pumped using a pressure pump (124, 224) to increase the pressure. The high pressure absorbed vapors (129, 229) are heated by the bottom product (107, 207) from the first (106) and second distillation column (206), in the corresponding solution heat exchangers (120, 220) before it is recycled back to the respective distillation column (106, 206).
The refrigerant bleed (1 19, 219) ensures that water, which comes with product (115, 215) from the first (114) and the second refrigerant heat exchanger (214) respectively, in a very small amount but does not evaporate in the evaporator, does not accumulate in the evaporator (112 and 212) and dilute the refrigerant therein. Such dilution will reduce the output pressure which the vapors exert on the absorber. The distillation columns (106, 206) need a reflux which can be provided from respective condenser for improving the concentration of refrigerant in each condenser. The refrigerant bleed (119 and 219) from the evaporator (which comes out at a low pressure in the system) (112, 212) can also serve as the reflux. The refrigerant bleed (119 and 219) coming out of the evaporator (112 and 212) will be at the same temperature as the refrigeration temperature. This refrigerant bleed (119 and 219) is pumped, using pump (122), to increase the pressure before being transferred to high pressure side of the system. The 'coldness' in this high pressure refrigerant bleed (121 and 221) is recovered by the bleed heat exchanger (114 and 214) and then the bleed (123 and 223) goes to respective distillation column (106, 206) as reflux.
Other modifications to the refrigeration system depicted in FIG. 1 can be envisioned by those skilled in the art and are encompassed within the scope and spirit of the invention depicted in FIG. 1.
The system allows the use of separate working fluids in each loop and this use of separate working fluid in each loop allows the selection of a working fluid that is best suited to the temperature and pressure levels in that loop.
Suitable working fluids can be of any conventional variety known in the art, including, but not limited to, the ones given below. Thus, the first and second working fluid is selected from a group consisting of ammonia-water, lithium bromide-water, carbon dioxide-water, ionic liquids, sulfur dioxide and water; mixed hydrocarbons; ammonia and brine; sulfur dioxide and brine, ammonia and sodium thiocyanate, ammonia/sodium thiocyanate and lithium thiocyanate, methanol/lithium bromide and zinc bromide and R-22/E-181 and R123a/ETFE. The first and second working fluid may be same or different in each of the first and second loop for e.g. the first loop can have lithium bromide-water as the working fluid and the second loop can have ammonia-water as the working fluid. The working fluid may be of any composition that will meet the required temperature, pressure and heat transfer requirements of the system. Alternatively, operating temperature and pressure ranges for the overall system may be defined by mechanical limitations of desired equipment, such as the maximum operational pressure of a preferred heat exchanger or the desired approach temperature for the product temperature against ambient conditions. When these additional considerations are imposed on the system, the working fluid composition will be adjusted to meet these preferred ranges. Preferred working fluids are those listed and discussed above. Ammonia water or ammonia brine fluids are especially preferred. However, those skilled in the art will recognize that in many applications other working fluids may be used to practice the invention.
The distillation column (106 and 206), reboiler (104 and 204) and the condenser (108 and 208) side of each of the first (102) and the second (202) loop of the system (100) comprise the high pressure side and the absorber (118 and 218) and evaporator (112 and 212) side comprise the low pressure side.
The pressure in the absorption refrigeration cycle can be controlled or regulated using pressure regulating means. The pressure regulating means comprises at least one of valves, pumps and/or an inert component. The valve (110, 210), in a preferred embodiment, is situated between the first and second refrigerant heat exchanger (116 and 216) and corresponding evaporator (112 and 212) and the low pressure refrigerant bleed (141, 241) flowing from the first and second refrigerant heat exchanger (116 and 216) to the corresponding evaporator (112, 212) is throttled through the throttle valve (110, 210) to reduce its pressure.
The absorbed liquid (127, 227) from the absorber (118 and 218), which is at a low pressure, is pumped before being transferred to the high pressure reboiler (104 and 204) or distillation column (106 and 206). Similarly, the refrigerant bleed (141, 241) from each of the first (112) and second evaporator (212) is at low pressure and is pumped before being transferred to the corresponding bleed heat exchanger. Thus, a first pump (124) and a second pump (224), in a preferred embodiment, are situated between the absorber (118 and 218) and the corresponding reboiler (104 and 204) or distillation column (106 and 206) and a third pump (122) and a fourth pump (222) are situated between each of the first (112) and second evaporators (212) and corresponding bleed heat exchangers (114, 214).
The inert component nearly equalizes the total pressures in the two sides of the system - that is the high pressure side and the low pressure side. The inert component is kept confined to the evaporator-absorber side. The inert component adds to the total pressure of the system bringing it nearly up to the high pressure side level. The absorbed liquid (127, 227) from each of the first and second absorber (118, 218) to the corresponding reboiler (104, 204) or distillation column (106, 206) as feed requires pumping. The pumping power depends on the flow rate and total pressure difference between the two sides. The inert component reduces this load and thereby reduces consumption of mechanical/electrical energy. The inert component can be selected from any of the conventional compounds known in the art, such as hydrogen, helium, nitrogen argon etc.
Using only pumps for regulating the pressure will result in greater energy consumption. On the other hand, use of the inert component alone with no pumps will lead to a passive flow between the two sides which will be very difficult to control. Thus, to increase the efficiency and decrease power consumption, in an embodiment, the process utilizes inert component to reduce the pressure difference and the pumps to control the flow of refrigerant.
A particular embodiment of the invention includes biomass being fed to the biogas power generator and the waste heat from this is utilized as the low grade heat supplied to the reboiler of the absorption refrigeration system (100). A negligible amount of electrical power needs to be provided for the operation of pressure pumps and other controls. In case a vapor cycle liquid piston pump is being used, pumps can be operated using no electrical power and only hot water as the heat source. In a preferred embodiment, the electrical power can be generated using a
battery, where the battery can be hand-powered recharge battery or a small biogas operated generator and battery charger. Similarly, other sources of low temperature or low grade heat including heat generated by using sunlight in a solar water generator or in solar photovoltaic panels with battery backup, biogas or other alternative fuels can be used. The low grade heat source encompasses a wide range of temperatures.
According to another embodiment, the process further comprises storing the refrigeration produced by the system (100) in a phase change material (PCM) or an insulated reservoir. The stored refrigeration can be utilized at a desirable location as and when needed. In these above embodiments, there is little or no reliance on grid electric power for the system operating on low grade heat as a form of energy.
The evaporator (112) of the first loop (102) removes heat from the condenser (108) or the absorber (114) of the second loop. The absorber (118) and the condenser (108) of the first loop (102) and the absorber (218) of the second loop (202) are cooled by normal cooling water. Refrigeration at the required application temperature is achieved from the evaporator (212) of the second loop (202).
Although the present invention has been described with particularity and in detail, the following examples provide further illustration of the invention and are understood not to limit the scope of the invention.
EXAMPLES
An absorption refrigeration system, in accordance with the present invention and the figure 1, utilizing a dual cycle with condenser evaporator coupling was used in the below said examples.
1) The temperature of the low grade heat generated was 8O0C. This heat was then provided to the absorption refrigeration system, in accordance with the present invention and the figure 1 , which included a dual cycle with condenser evaporator coupling. The temperature of the cooling water used was 40 0C. Using the above heat source and cooling water, the present novel absorption refrigeration system gave a refrigeration temperature of 0°C. According to the definition of low grade heat, R = (80 - 40) ÷ (40 - 0) = l
2) The temperature of the low grade heat generated was 120°C. This heat was then provided to the absorption refrigeration system, in accordance with the present invention and the figure 1 , which included a dual cycle with condenser evaporator coupling. The temperature of the cooling water used was 40 °C. Using the above heat source and cooling water, the present novel absorption refrigeration system gave a refrigeration temperature of 00C.
According to the definition of low grade heat, R = (120 - 40) ÷ (40 - 0)) = 2
3) The temperature of the low grade heat generated was 55°C. This heat was then provided to the absorption refrigeration system, in accordance with the present invention and the figure 1 , which included a dual cycle with condenser evaporator coupling. The temperature of the cooling water used was 15 0C. Using the above heat source and cooling water, the present novel absorption refrigeration system gave a refrigeration temperature of -5°C.
According to the definition of low grade heat, R = (55 - 15) ÷ (15 -(S)) = 2
4) The temperature of the low grade heat generated was 55°C. This heat was then provided to the absorption refrigeration system, in accordance with the present invention and the figure 1 , which included a dual cycle with condenser evaporator coupling. The temperature of the cooling water used was 15 0C. Using the above heat source and cooling water, the present novel absorption refrigeration system gave a refrigeration temperature of -250C. According to the definition of low grade heat, R = (55 - 15) ÷ (15 -(-25)) = 1
As seen from the above examples, the present absorption refrigeration system allows the utilization of heat sources at various temperatures and furthermore, the system produces refrigeration with high efficiency.
While the invention is described in connection with specific examples, it is to be understood that this is for illustrative purposes only. Many alternatives, modifications and variations will be apparent to those skilled in the art in the light of the above example; and such alternatives, modifications and variations fall within the spirit and scope of the appended claims.
Claims
1. An absorption refrigeration system comprising:
a. a first loop comprising a first working fluid, a first reboiler, a first distillation column, a first condenser, a first evaporator and a first absorber, all operatively connected together, a first bleed heat exchanger for cooling a condensed product from the first condenser using a refrigerant bleed from the first evaporator, a first refrigerant heat exchanger for cooling a condensed product from the bleed heat exchanger using a refrigerant vapor from the first evaporator, and a first solution heat exchanger for heating an absorbed product from the first absorber using a bottom product from the first distillation column; and, b. a second loop in thermal connection with the first loop, the second loop comprising a second working fluid, a second reboiler, a second distillation column, a second condenser, a second evaporator and a second absorber, all operatively connected together, a second bleed heat exchanger for cooling a condensed product from the second condenser using a refrigerant bleed from the second evaporator, a second refrigerant heat exchanger for cooling a condensed product from the bleed heat exchanger using a refrigerant vapor from the second evaporator, and a second solution heat exchanger for heating an absorbed product from the second absorber using a bottom product from the second distillation column, wherein each of the first and second reboiler is provided with low grade heat; and c. at least one pressure regulating means selected from at least one valve, a plurality of pressure pumps and/or an inert component.
2. The absorption refrigeration system as claimed in claim 1, wherein at least one of the second condenser and the second absorber heats the first evaporator.
3. The absorption refrigeration system as claimed in claim 1, wherein the low grade heat used is such that a ratio of the difference between low grade heat temperature and heat sink temperature to the difference heat sink temperature and refrigeration temperature is less than or equal to 2.5.
4. The absorption refrigeration system as claimed in claim 1 , wherein the first working and the second fluid is selected from a group consisting of ammonia-water, lithium bromide-water, carbon dioxide-water, ionic liquids, sulfur dioxide and water; mixed hydrocarbons; ammonia and brine; sulfur dioxide and brine, ammonia and sodium thiocyanate, ammonia/sodium thiocyanate and lithium thiocyanate, methanol/lithium bromide and zinc bromide and R-22/E-181 and R123a/ETFE.
5. The absorption refrigeration system as claimed in claim 1, wherein the valve is situated between each of the first and second refrigerant heat exchanger and the respective evaporators.
6. The absorption refrigeration system as claimed in claim 1, wherein a first pump and second pump are situated between each of the first and second evaporators and corresponding bleed heat exchangers and a third pump and fourth pump are situated between each of the first and second absorbers and their corresponding distillation columns or reboilers.
7. The absorption refrigeration system as claimed in claim 1, wherein the inert component is present in each of the first and second evaporators and first and second absorbers.
8. The absorption refrigeration system as claimed in claim 1, wherein the system further comprises one or more additional loops through coupling either the first or second evaporator with the additional loop condenser or the additional loop absorber.
9. A refrigeration process in an absorption refrigeration system comprising a first loop and a second loop, the improvement in the process comprising steps of: a. thermally coupling the first loop and the second loop, wherein the first loop comprises a first working fluid, a first distillation column, a first reboiler, a first condenser, a first absorber, a first evaporator, a first bleed heat exchanger, a first refrigerant heat exchanger and a first solution heat exchanger, all operatively connected together, and the second loop comprises a second working fluid, a second distillation column, a second reboiler, a second condenser, a second absorber, a second evaporator, a second bleed heat exchanger, a second refrigerant heat exchanger and a second solution heat exchanger, all operatively connected together; b. providing low grade heat to each of the first and second reboiler; c. cooling condensed product received from each of the first and second condensers, with the refrigerant bleed from the corresponding evaporator, in each of the first and second bleed heat exchangers; d. cooling condensed product received from each of the first and second bleed heat exchangers, with the refrigerant vapor from the corresponding evaporator, in each j of the first and second refrigerant heat exchangers; e. heating absorbed product received from each of the first and second absorber, with a bottom product from corresponding distillation column, in each of the first and second solution heat exchangers; and f. providing at least one pressure regulating means selected from at least one valve, a plurality of pressure pumps and/or an inert component in the absorption refrigeration system.
10. The process for refrigeration as claimed in claim 9, wherein step (a) comprises heating the first evaporator using at least one of the second condenser and the second absorber.
11. The absorption refrigeration system as claimed in claim 9, wherein the low grade heat used is such that a ratio of the difference between low grade heat temperature and heat sink temperature to the difference heat sink temperature and refrigeration temperature is less than or equal to 2.5.
12. The process for refrigeration as claimed in claim 9, wherein step (c) comprises cooling the condensed product from each of the first and second condenser before transferring to the corresponding refrigerant heat exchangers, thereby heating the refrigerant bleed from each of the first and second evaporators.
13. The process for refrigeration as claimed in claim 9, wherein the bleed from each of the first and second bleed heat exchangers is refluxed to the corresponding distillation columns.
14. The process for refrigeration as claimed in claim 9, wherein step (d) comprises cooling the condensed product from each of the first and second bleed heat exchanger, thereby heating the refrigerant vapor from each of the first and second evaporators before transferring to the corresponding absorbers.
15. The process for refrigeration as claimed in claim 9, wherein step (e) comprises cooling the bottom product from each of the first and second distillation columns before transferring to the absorbers, thereby heating the absorbed product from each of the first and second absorbers before transferring to the corresponding distillation columns.
16. The process for refrigeration as claimed in claim 9, further comprising reducing the pressure of condensed product from each of the first and second refrigerant heat exchanger before transferring to the corresponding evaporators.
17. The process for refrigeration as claimed in claim 9, further comprising increasing pressure of absorbed product from each of the first and second absorbers before transferring to the corresponding distillation columns and pressure of refrigerant bleed from each of the first and second evaporator before transferring to the corresponding bleed heat exchangers.
18. The process for refrigeration as claimed in claim 9, further comprising providing an inert component in each of the first and second evaporator to increase the pressure of refrigerant vapor.
19. A refrigeration process in an absorption refrigeration system comprising a first loop and a second loop, the process comprising steps of: a) thermally coupling the first loop and the second loop, wherein the first loop comprises a first working fluid, a first distillation column, a first reboiler, a first condenser, a first absorber, a first evaporator, a first bleed heat exchanger, a first refrigerant heat exchanger and a first solution heat exchanger, all operatively connected together, and the second loop comprises a second working fluid, a second distillation column, a second reboiler, a second condenser, a second absorber, a second evaporator, a second bleed heat exchanger, a second refrigerant heat exchanger and a second solution heat exchanger, all operatively connected together; b) separating the working fluid in each of the first and second distillation column, to produce a distillation product and a bottom product, using corresponding first and second reboiler, wherein each of the first and second reboiler utilizes a low grade heat; c) condensing the distilled top product in each of the first and second condenser; d) evaporating the condensed product in each of the first and second evaporator; e) cooling the condensed product received from each of the first and second condensers with the refrigerant bleed from the corresponding evaporators, in each of the first and second bleed heat exchangers; f) cooling the cooled condensed product, from each of the first and second bleed heat exchangers, with the refrigerant vapor from the corresponding evaporator, in each of the first and second refrigerant heat exchangers; . g) transferring the refrigerant product from each of the first and second refrigerant heat exchanger to corresponding first and second absorber; h) heating the absorbed product, from each of the first and second absorber, with a bottom product from corresponding distillation column, in each of the first and second solution heat exchangers; and i) providing at least one pressure regulating means selected from at least one valve, a plurality of pressure pumps and/or an inert component in the absorption refrigeration system.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IN1338MU2008 | 2008-06-26 | ||
| IN1338/MUM/2008 | 2008-06-26 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2010038236A2 true WO2010038236A2 (en) | 2010-04-08 |
| WO2010038236A3 WO2010038236A3 (en) | 2010-08-12 |
Family
ID=40578361
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IN2008/000430 WO2009157004A1 (en) | 2008-06-26 | 2008-07-07 | An absorption refrigeration system and a process for refrigeration utilizing the same |
| PCT/IN2009/000364 WO2010038236A2 (en) | 2008-06-26 | 2009-06-25 | An absorption refrigeration system and a process for refrigeration utilizing the same |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IN2008/000430 WO2009157004A1 (en) | 2008-06-26 | 2008-07-07 | An absorption refrigeration system and a process for refrigeration utilizing the same |
Country Status (1)
| Country | Link |
|---|---|
| WO (2) | WO2009157004A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009157004A1 (en) * | 2008-06-26 | 2009-12-30 | Bp Alternative Energy Holdings Limited | An absorption refrigeration system and a process for refrigeration utilizing the same |
| JP7444356B2 (en) | 2019-12-06 | 2024-03-06 | サーマルガジェット株式会社 | Cooling system |
| WO2023012513A2 (en) * | 2021-08-06 | 2023-02-09 | Mihail Dan Staicovici | Gas liquefaction procedure and applying plant |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5572884A (en) | 1994-11-04 | 1996-11-12 | The Ohio State University Research Foundation | Heat pump |
| US6397625B1 (en) | 1998-09-04 | 2002-06-04 | Solarfrost International Ltd. | Absorption refrigeration machine |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4337625A (en) * | 1981-03-02 | 1982-07-06 | Battelle Development Corp. | Waste heat driven absorption refrigeration process and system |
| IL72882A0 (en) * | 1984-09-06 | 1984-12-31 | Univ Ben Gurion | Absorption system for refrigeration and heat pumping |
| US4667485A (en) * | 1986-03-14 | 1987-05-26 | Gas Research Institute | Absorption refrigeration and heat pump system |
| DE3716455A1 (en) * | 1986-10-20 | 1988-04-28 | Vinz Peter | METHOD AND DEVICE FOR QUANTITY-CONTROLLED CONTINUOUS LIQUID EXCHANGE IN DISTILLATION SYSTEMS AND ABSORPTION REFRIGERATION CIRCUITS |
| WO2009157004A1 (en) * | 2008-06-26 | 2009-12-30 | Bp Alternative Energy Holdings Limited | An absorption refrigeration system and a process for refrigeration utilizing the same |
-
2008
- 2008-07-07 WO PCT/IN2008/000430 patent/WO2009157004A1/en active Application Filing
-
2009
- 2009-06-25 WO PCT/IN2009/000364 patent/WO2010038236A2/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5572884A (en) | 1994-11-04 | 1996-11-12 | The Ohio State University Research Foundation | Heat pump |
| US6397625B1 (en) | 1998-09-04 | 2002-06-04 | Solarfrost International Ltd. | Absorption refrigeration machine |
Non-Patent Citations (2)
| Title |
|---|
| "Performance evaluation of Ammonia Absorption Refrigeration cycle based on exergetic coefficient of performance", INT. J. EXERGY., vol. 4, no. 1, 2007, pages 19 - 37 |
| "Simulation of dual Ammonia Absorption Refrigeration cycle for effective utilization of low temperature heat source", INT. J. EXERGY., vol. 4, no. 3, 2007, pages 253 - 270 |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2010038236A3 (en) | 2010-08-12 |
| WO2009157004A1 (en) | 2009-12-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Wang et al. | Solar driven air conditioning and refrigeration systems corresponding to various heating source temperatures | |
| Li et al. | Technology development in the solar absorption air-conditioning systems | |
| Aman et al. | Residential solar air conditioning: Energy and exergy analyses of an ammonia–water absorption cooling system | |
| Hwang et al. | Review of solar cooling technologies | |
| US4813242A (en) | Efficient heater and air conditioner | |
| Altamirano et al. | Review of small-capacity single-stage continuous absorption systems operating on binary working fluids for cooling: Theoretical, experimental and commercial cycles | |
| Vasilescu et al. | Solar driven double-effect absorption cycles for sub-zero temperatures | |
| KR101914487B1 (en) | Hybrid system of absorption type refrigeration and heat pupm for supplying cooling and steam simultaneously | |
| CN101196351A (en) | High-efficiency low-temperature absorptive refrigerating machine | |
| CN101458007B (en) | Solution energy-saving equipment based on film distillation technology and method thereof | |
| Said et al. | Analysis of a solar powered absorption system | |
| Mittal et al. | The study of solar absorption air-conditioning systems | |
| Khamooshi et al. | Simulation and optimization of novel configurations of triple absorption heat transformers integrated to a water desalination system | |
| CN101968288A (en) | Absorption-compression composite refrigeration cycle system | |
| Mahmoudi et al. | A novel combination of absorption heat transformer and refrigeration for cogenerating cooling and distilled water: Thermoeconomic optimization | |
| WO2010038236A2 (en) | An absorption refrigeration system and a process for refrigeration utilizing the same | |
| CN102645050A (en) | Ammonia water absorbing-type refrigeration system and method using concentration-adjustable working medium | |
| CN111947302A (en) | Concentration-variable directly-heated heat pump water heater with flash evaporator and working method thereof | |
| CN109611169B (en) | Non-azeotropic working medium organic Rankine cycle system with adjustable assembly dynamic | |
| CN107588575B (en) | Cold and hot electricity multi-combined supply system based on multistage solar heat collector | |
| Okour et al. | Performance analysis of solar absorption ice maker driven by parabolic trough collector. | |
| CN102338504A (en) | Absorption-compression type dual-temperature second-kind heat pump system | |
| CN103206354A (en) | Method for improving liquid transportation efficiency in solar-thermal power generation | |
| US4283918A (en) | Liquid phase separation in absorption refrigeration | |
| Mohanty et al. | Thermodynamic Performance Analysis of a Solar Vapour Absorption Refrigeration System |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 09796472 Country of ref document: EP Kind code of ref document: A2 |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| WWE | Wipo information: entry into national phase |
Ref document number: 118/MUMNP/2011 Country of ref document: IN |
|
| 122 | Ep: pct application non-entry in european phase |
Ref document number: 09796472 Country of ref document: EP Kind code of ref document: A2 |