Multi-effect cooling system utilizing heat from an engine

BACKGROUND OF THE INVENTION

An absorption cooling system provides a method of cooling using a primary heat source as a primary energy source. Absorption systems function in a similar manner to vapor compression systems. However, instead of using a compressor to compress refrigerant and supply the refrigerant to a condenser, absorption systems use a solution circuit. The solution circuit consists of an absorber and a generator (also known as a desorber) supplied with an absorbent. The absorbent absorbs the refrigerant in the absorber and desorbs the refrigerant in the generator, thus bringing the refrigerant from a low pressure, low temperature state to a high pressure, high temperature state. The generator then supplies the refrigerant to a condenser.

Multi-effect absorption systems function in a similar manner to the basic single effect absorption system. However, they include at least two generators and either an additional absorber, an additional condenser or both. Multi-effect absorption systems are typically more efficient than single effect absorption systems because they use heat dissipated from the additional absorber, additional condenser or both and apply that heat to one of the generators for use during the desorbing process.

An adsorption cooling system provides a method of cooling using a primary heat source as a primary energy source. Adsorption systems function in a similar manner to absorption systems. However, instead of using an adsorber and generator, the adsorption system uses two adsorber chambers operated in bi-directional modes. In one mode, the first adsorber chamber adsorbs refrigerant from an evaporator while the second adsorber chamber desorbs refrigerant; which is then supplied to a condenser and the evaporator in turn. In another mode, the second adsorber chamber adsorbs refrigerant from the evaporator while the first adsorber chamber desorbs refrigerant; which is then supplied to the condenser and the evaporator in turn. In both modes, heat provides the energy for desorbing the refrigerant from the adsorber chamber.

Multi-effect adsorptions systems function in a similar manner to the basic single effect adsorption system. However, they include at least another set of adsorber chambers. Multi-effect adsorption systems are typically more efficient than single effect adsorption systems because they use heat dissipated from the additional adsorber or other elements and apply that heat to one of the desorbing adsorber chambers for use during the desorbing process.

In multi-effect cooling systems, the use of waste heat generated by elements of the multi-effect cooling system itself improves the coefficient of performance. However, additional improvement of the coefficient of performance would be useful.

SUMMARY OF THE INVENTION

In accordance with an example, a method of operating a multi-effect cooling system uses heat generated from an engine having an exhaust system and cooling system. The multi-effect cooling system includes a primary desorber and a secondary desorber. The primary desorber is heated using heat from the exhaust system. The secondary desorber is heated using heat from the cooling system.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and not limitation in the accompanying figures in which like numeral references refer to like elements, and wherein:

FIG. 1 shows a simplified schematic illustration of a multi-effect cooling system according to an embodiment of the invention;

FIG. 2 shows a simplified model of an absorption system in accordance with an embodiment of the invention;

FIG. 3 shows a simplified model of an absorption system in accordance with another embodiment of the invention;

FIGS. 4A and 4B, collectively, show a simplified model of an adsorption system in accordance with another embodiment of the invention;

FIGS. 5A and 5B, collectively, show a simplified model of an adsorption system in accordance with another embodiment of the invention;

FIG. 6 shows a flow diagram of an operational mode depicting a manner in which a multi-effect cooling system may be implemented according to an embodiment of the invention;

FIG. 7 shows a flow diagram of an operational mode depicting a manner in which a multi-effect cooling system may be implemented according to another embodiment of the invention;

FIG. 8 shows a flow diagram of an operational mode depicting a manner in which a multi-effect cooling system may be implemented according to another embodiment of the invention;

FIG. 9 shows a flow diagram of an operational mode depicting a manner in which a multi-effect cooling system may be implemented according to another embodiment of the invention; and

FIG. 10 shows a flow diagram of an operational mode depicting a manner in which a multi-effect cooling system may be implemented according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

For simplicity and illustrative purposes, the operation of a multi-effect cooling system is described by referring mainly to examples thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the examples. It will be apparent however, to one of ordinary skill in the art, that the examples described herein may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the examples described herein.

Throughout the present disclosure, reference is made to a primary desorber and a secondary desorber. Generally, a desorber may be defined as a device in a cooling system for desorbing refrigerant from a substance. The primary desorber may be defined as any desorber in a multi-effect cooling system that operates at a higher temperature and/or pressure than another desorber in the multi-effect cooling system. The secondary desorber may be defined as any desorber in a multi-effect cooling system that operates at a lower temperature and/or pressure than another desorber in the multi-effect cooling system.

In absorption type multi-effect cooling systems, the primary desorber is a primary generator that desorbs refrigerant from an absorbent while the secondary desorber is a secondary generator that desorbs refrigerant from an absorbent. The secondary generator operates at a lower temperature and/or pressure than the primary generator. The refrigerant may be water while the absorbent may be lithium bromide (Li—Br).

In adsorption type multi-effect cooling systems, the primary desorber is one of at least two primary adsorber chambers that desorbs refrigerant from an adsorbent while the secondary desorber is one of at least two secondary adsorber chambers that desorbs refrigerant from an adsorbent. The refrigerant may be water while the adsorbent may be silica gel.

Reference is also made to heat generated by an engine having an exhaust system and a cooling system. The heat generated by the engine may be defined as any heat produced as a result of fuel combustion by the engine. The engine may be any liquid cooled combustion engine that produces heat. The exhaust system may be defined as a system of pipes or conduits that carry waste gases and heat from the combustion engine to a predetermined location, usually outside of a compartment housing the engine. The cooling system may be defined as a system of pipes or conduits that carry a liquid from the engine to a radiator, which cools the liquid and returns it to the engine, in order to reduce the engine's temperature. In regards to the engine, reference is also made to a vehicle having the engine. The vehicle may be defined as any mobile apparatus including an engine as defined above. For example, the vehicle may be a boat, airplane, truck, car, train, or any other mobile device having an engine that generates heat.

According to an example of the invention, a multi-effect cooling system operates to cool an area. The area may include an insulated room or container for holding items (food and medicine are examples) at a predetermined temperature. The area may also include a room or container for holding heat producing devices such as electrical equipment. Additionally, the area may include a room or compartment occupied by a humans or animals. For example, the area may be the interior of a passenger car, a cabin on an airplane, a room located within a cruise ship, a data center located on a tractor-trailer, or simply an insulated storage compartment. The multi-effect cooling system may be located on a vehicle or on a static structure such as a building.

The multi-effect cooling system operates utilizing heat generated from an engine having an exhaust system and a cooling system. In general, the multi-effect cooling system includes a primary desorber and a secondary desorber and makes use of heat generated in one component to supply heat to the secondary desorber in order to increase the coefficient of performance for the entire system. In this manner, the total amount of energy required for cooling is reduced which saves money for the user and reduces strain on environmental resources, such as, coal, oil, and natural gas. The coefficient of performance for a multi-effect cooling system may be further increased by applying additional heat to the secondary desorber from another source. In the multi-effect cooling system, the primary desorber operates using heat from the exhaust system of the engine (in temperatures ranging from 300 to 800 degrees Celsius) while the secondary desorber operates using heat from the cooling system of the engine (in temperatures ranging from 80 to 90 degrees Celsius) in addition to heat generated from other components in the multi-effect cooling system.

In an example, the multi-effect cooling system may be a multi-effect absorption system including a primary generator (as the primary desorber), a secondary generator (as the secondary desorber), a primary condenser, a secondary condenser, an absorber, and an evaporator. The primary generator operates using heat from the exhaust system while the secondary generator operates using heat from the cooling system. In addition, the secondary generator may also operate using heat collected from the primary condenser. Under some circumstances, waste heat produced from a device being cooled by the multi-effect cooling system may be used to operate the secondary generator.

In another example, the multi-effect cooling system may be a multi-effect absorption system including a primary generator (as the primary desorber), a secondary generator (as the secondary desorber), a condenser, a primary absorber, a secondary absorber, and an evaporator. The primary generator operates using heat from the exhaust system while the secondary generator operates using heat from the cooling system. In addition, the secondary generator may also operate using heat collected from the primary absorber. Under some circumstances, waste heat produced from a device being cooled by the multi-effect cooling system may be used to operate the secondary generator.

In another example, the multi-effect cooling system may be a multi-effect adsorption system including a primary adsorber chamber (as the primary desorber), a secondary adsorber chamber (as the secondary desorber), a primary condenser, a secondary condenser, another primary adsorber chamber, another secondary adsorber chamber, and an evaporator. The primary adsorber chamber operates using heat from the exhaust system while the secondary adsorber chamber operates using heat from the cooling system. In addition, the secondary adsorber chamber may also operate using heat collected from the primary condenser. Under some circumstances, waste heat produced from a device being cooled by the multi-effect cooling system may be used to operate the secondary adsorber chamber.

In another example, the multi-effect cooling system may be a multi-effect adsorption system including a primary adsorber chamber (as the primary desorber), a secondary adsorber chamber (as the secondary desorber), a condenser, another primary adsorber chamber, another secondary adsorber chamber, and an evaporator. The primary adsorber chamber operates using heat from the exhaust system while the secondary adsorber chamber operates using heat from the cooling system. In addition, the secondary adsorber chamber may also operate using heat collected from the primary adsorber chamber. Under some circumstances, waste heat produced from a device being cooled by the multi-effect cooling system may be used to operate the secondary adsorber chamber.

In any of the examples described above, heat may be generated from components of the multi-effect cooling system such as condensers and absorbers. Efficiencies may be improved by dissipating this heat to the environment using air moving relative to a vehicle or water in contact with the vehicle. For example, moving air channeled through a radiator may dissipate heat generated by a condenser and thus increase the overall efficiency of the multi-effect cooling system. In another example, a heat exchanger, such as a heat transfer plate, in contact with a body of water, such as an ocean or lake, may dissipate heat generated by an absorber and may thus increase the overall efficiency of the multi-effect cooling system.

According to examples of the invention, total efficiency of the engine and multi-effect cooling system, taken as a unit, may be increased through a variety of manners. For instance, heat from the exhaust system would normally be wasted. However, the primary desorber of the multi-effect cooling system uses the exhaust heat to operate. Therefore, the engine does not need to operate additional electrical power generators or compressors to cool an area, thus reducing the total load on the engine. In addition, extra energy used to cool the engine itself, such as energy used to operate a radiator fan, is reduced by using heat from the cooling fluid to operate the secondary desorber. This provides a dual benefit by reducing energy consumption of the engine and increasing the coefficient of performance of the multi-effect cooling system. Additionally, using heat from the cooling system may reduce the amount of heat supplied to the primary desorber from the exhaust system. This may reduce pressure in the exhaust system reducing the engine's workload and thus increasing the engine's efficiency.

With reference first to FIG. 1, there is shown a block diagram of a vehicle or static structure 100 having an engine 102, a multi-effect cooling system 104, and a cooled area 106. The engine 102 includes an exhaust system 108 and a cooling system 110. The multi-effect cooling system 104 includes a primary desorber 112, a secondary desorber 114, and an evaporator 116. The exhaust system 108 supplies heat to the primary desorber 112 in any one of a variety of manners. One example includes routing hot exhaust gasses through a conduit represented by arrow 118 to a heat exchanger 120 that then provides heat to the primary desorber 112. The hot exhaust gasses may then be routed to the environment through a conduit designated by arrow 122. In addition or alternatively, the hot exhaust gases may be routed back to the exhaust system 108 through a conduit designated by arrow 124 for further processing through a catalytic converter or muffler.

The cooling system 110 supplies heat to the secondary desorber 114 in any one of a variety of manners. One example includes routing hot cooling fluid through a conduit represented by arrow 126 to a heat exchanger 128 that then provides heat to the secondary desorber 114. The cooling fluid may then be routed back to the cooling system 110 through a conduit designated by arrow 130.

The multi-effect cooling system 104 may include additional components as shown and described in FIGS. 2-5B. The additional components may vary in number and type depending on the type of multi-effect cooling system 104 employed in the vehicle or static structure 100. For example, absorption systems use absorbers and generators while adsorption systems use adsorber chambers for both adsorption and desorption processes. Some of the additional components, designated by box 132, produce heat that is dissipated to the environment, shown by arrow 134, through a heat exchanger 136.

In one example, the heat exchanger 136 may represent a pyroelectric device that may be used to generate electricity to charge batteries or provide additional electrical power to various other components from the heat dissipated by the component 132. Examples of suitable pyroelectric devices may be found in co-pending and commonly assigned U.S. patent application Ser. No. 10/678,268, filed on Oct. 6, 2003, and entitled, “Converting Heat Generated By A Component To Electrical Energy,” the disclosure of which is hereby incorporated by reference in its entirety.

The multi-effect cooling system 104 provides cooling to (removes heat from) the cooled area 106 using the evaporator 116 through any one of a variety of manners. In one example, the evaporator 116 may exchange heat through a heat exchanger 138 removing heat from a fluid that is then routed to the cooled area 106 through a conduit designated by arrow 140. The fluid absorbs heat from the cooled area 106 and is routed back to the heat exchanger 138 through a conduit designated by arrow 142.

Referring now to FIG. 2, there is shown a simplified model of a multi-effect absorption system 200 according to an embodiment of the invention. The multi-effect absorption system 200 illustrated in FIG. 2 is a double-effect double-condenser absorption system and includes an evaporator 202, an absorber 204, a secondary generator 206 (also known as a secondary desorber 114 shown in FIG. 1), a primary generator 208 (also known as a primary desorber 112 shown in FIG. 1), a primary condenser 210 and a secondary condenser 212. In general, absorption systems use a refrigerant and an absorbent. For example, an absorption system may use an ammonia/water combination, a water/lithium bromide combination, or the like. The refrigerant vaporizes in the evaporator 202 thereby absorbing heat Q_E216 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the absorber 204, as indicated by the arrow 218, and the vaporized refrigerant is absorbed into the absorbent contained in the absorber 204, thereby dissipating heat Q_A220. The heat Q_A220 may be dissipated to the environment through heat exchanger 136 shown in FIG. 1.

The absorbent and the absorbed refrigerant flow through the secondary generator 206 through operation of a pump 222 and then to the primary generator 208 through operation of a pump 224, as indicated by the arrows 226 and 228 respectively. Alternatively, the absorbent and the absorbed refrigerant may flow to the primary generator 208 directly through operation of a pump and direct line (not shown). Heat Q_P230 is supplied into the primary generator 208 from the exhaust system 108 shown in FIG. 1 and the heat Q_P230 desorbs some of the vaporized refrigerant from the absorbent in the primary generator 208. The desorbed refrigerant flows to the primary condenser 210, as indicated by the arrow 232, which condenses the refrigerant and dissipates heat Q_PC234. The condensed refrigerant flows from the primary condenser 210 to the secondary condenser 212 through a valve 236, as indicated by the arrow 238.

The absorbent with the remainder of the absorbed refrigerant then flows from the primary generator 208 to the secondary generator 206 through a valve 240, as indicated by the arrow 242. Heat Q_PC234 dissipated from the desorbed refrigerant is supplied from the primary condenser 210 to the secondary generator 206. In addition, heat Q_CS244 collected from the cooling system 110 of the engine 102 shown in FIG. 1 is also supplied to the secondary generator 206. The heat Q_PC234 and Q_CS244 desorbs additional refrigerant from the absorbent in the secondary generator 206. Through use of the heat Q_CS244 received from the cooling system 110, the amount of heat necessary for the primary generator 208 may be reduced.

The additional desorbed refrigerant then flows to the secondary condenser 206, as indicated by the arrow 246, which condenses the refrigerant and dissipates heat Q_SC248. The heat Q_SC248 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1. The condensed refrigerant from the primary condenser 210 contained in the secondary condenser 212 mixes with the refrigerant condensed from the secondary condenser 212. The mixed condensed refrigerant then flows through a valve 250 back to the evaporator 202, as indicated by the arrow 252. Through operation of the above-identified process, the refrigerant is returned to a lower temperature and lower pressure state to thereby cool the cooled area 106. The above-identified process may then be repeated on a substantially continuous basis to provide heat removal from the cooled area 106 through the evaporator 202.

The absorbent separated from the absorbed refrigerant in the secondary generator 206 flows back to the absorber 204 through a valve 254 as indicated by the arrow 256. In this regard, the absorbent may be re-used in absorbing the vaporized refrigerant received from the evaporator 202.

FIG. 3 shows a simplified model of a multi-effect absorption system 300 according to another embodiment of the invention. The multi-effect absorption system 300 illustrated in FIG. 3 is a double-effect double-absorber absorption system and includes an evaporator 302, a secondary absorber 304, a primary absorber 306, a secondary generator 308 (also known as a secondary desorber 114 shown in FIG. 1), a primary generator 310 (also known as a primary desorber 112 shown in FIG. 1), and a condenser 312. In general, absorption systems use a refrigerant and an absorbent as described hereinabove. The refrigerant vaporizes in the evaporator 302 thereby absorbing heat Q_E314 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the secondary absorber 304, as indicated by the arrow 316, and a portion of the vaporized refrigerant is absorbed into a secondary absorbent contained in the secondary absorber 304, thereby dissipating heat Q_SA318. The heat Q_SA318 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

The absorbent and the absorbed refrigerant flow to the secondary generator 308 through operation of a pump 320, as indicated by the arrow 322. The remaining refrigerant flows to the primary absorber 306, as indicated by the arrow 324, and the remaining refrigerant is absorbed into a primary absorbent contained in the primary absorber 306, thereby dissipating heat Q_PA326. The heat Q_PA326 is supplied to the secondary generator 308.

The primary absorbent with the remaining refrigerant flow to the primary generator 310 through operation of a pump 328, as indicated by the arrow 330. Heat Q_P332 is supplied to the primary generator 310 from the exhaust system 108 shown in FIG. 1 and the heat Q_P332 desorbs most of the refrigerant from the primary absorbent in the primary generator 310. The desorbed refrigerant flows to the secondary generator 308, as indicated by the arrow 334. The primary absorbent flows through valve 336 to the primary absorber 306, as indicated by the arrow 338, for re-use in the primary absorber 306.

As indicated hereinabove, heat Q_PA326 dissipated from the desorbed refrigerant is supplied from the primary absorber 306 to the secondary generator 308. In addition, heat Q_CS340 collected from the cooling system 110 of the engine 102 shown in FIG. 1 is also supplied to the secondary generator 308. The heat Q_PA326 and heat Q_CS340 desorbs refrigerant from the secondary absorbent at the secondary generator 308. Through use of the heat Q_CS340 received from the cooling system 110, the amount of heat necessary for the primary generator 310 may be reduced.

The secondary absorbent then flows through valve 342 to the secondary absorber 304, as indicated by the arrow 344, for re-use in the secondary absorber 304. The desorbed refrigerant from the primary generator 310 contained in the secondary generator 308 mixes with the refrigerant desorbed at the secondary generator 308. The combined refrigerant then flows to the condenser 312, as indicated by the arrow 346. The condenser 312 generally operates to condense the combined refrigerant and thereby dissipate heat Q_C348. The heat Q_C348 may be dissipated to the environment through heat exchanger 136 shown in FIG. 1. The condensed refrigerant then flows through valve 350 back to the evaporator 304, as indicated by the arrow 352. Through operation of the above-identified process, the refrigerant is returned to a lower temperature and lower pressure state to thereby cool the cooled area 106. The above-identified process may then be repeated on a substantially continuous basis to provide heat removal from the cooled area 106 through the evaporator 302.

Referring now to FIGS. 4A and 4B, there is shown, collectively, a simplified model of a multi-effect adsorption system 400 according to an example of the invention. FIG. 4A shows the forward cycle while FIG. 4B shows the reverse cycle. Some components in the multi-effect adsorption system 400 function as desorbers in the forward cycle and then function as adsorbers in the reverse cycle. As a consequence, some items in FIGS. 4A and 4B are located in different positions in the simplified model. The multi-effect adsorption system 400 operates according to a reversible process, a forward cycle and a reverse cycle, each of which provides cooling by removing heat in the evaporator 402. The multi-effect adsorption system 400 is a double-effect double-condenser adsorption system and includes an evaporator 402, a first primary adsorber chamber (PAC1) 404, a second primary adsorber chamber (PAC2) 406 (also known as the primary desorber 112 shown in FIG. 1), a first secondary adsorber chamber (SAC1) 408, a second secondary adsorber chamber (SAC2) 410 (also known as a secondary desorber 114 shown in FIG. 1), a primary condenser 412 and a secondary condenser 414. In general, adsorption systems use a refrigerant and an adsorbent. For example, an adsorption system may use water and silica gel or Kansi carbon combinations.

In the multi-effect adsorption system 400, the first primary adsorber chamber (PAC1) 404 and the second primary adsorber chamber (PAC2) 406 may be formed as two separate chambers arranged in such a manner as to transfer heat between one another. Similarly, the first secondary adsorber chamber (SAC1) 408 and the second secondary adsorber chamber (SAC2) 410 may be formed as two separate chambers arranged in such a manner as to transfer heat between one another.

Referring now to the forward cycle illustrated in FIG. 4A, some of the refrigerant vaporizes in the evaporator 402, thereby absorbing heat Q_E416 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the first secondary adsorber chamber 408, as indicated by the arrow 418, and the vaporized refrigerant is adsorbed into the adsorbent contained in the first secondary adsorber chamber 408, thereby dissipating heat Q_SA420. Additionally, more of the refrigerant vaporizes in the evaporator 402 thereby absorbing heat Q_E416 from, for instance, cooling fluid heated by adsorbing heat from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the first primary adsorber chamber 404, as indicated by the arrow 422, and the vaporized refrigerant is adsorbed into the adsorbent contained in the first primary adsorber chamber 404, thereby dissipating heat Q_PA424. The heat Q_SA420 and Q_PA424 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

The refrigerant adsorbed into the first secondary adsorber chamber 408 and the first primary adsorber chamber 404 originated from the second secondary adsorber chamber 410 and the second primary adsorber chamber 406, respectively. Some of the refrigerant is desorbed from the second primary adsorber chamber 406. Heat Q_P426 is supplied into the second primary adsorber chamber 406 from the exhaust system 108 shown in FIG. 1 and the heat Q_P426 desorbs some of the refrigerant from the adsorbent in the second primary adsorber chamber 406. The desorbed refrigerant flows to the primary condenser 412 as indicated by the arrow 428 which condenses the refrigerant and dissipates heat Q_PC430. The condensed refrigerant flows from the primary condenser 412 to the secondary condenser 414, as indicated by the arrow 432.

Likewise, some of the refrigerant is desorbed from the second secondary adsorber chamber 410. The heat Q_PC430 is supplied to the second secondary adsorber chamber 410 along with the heat Q_CS434 from the cooling system 110 shown in FIG. 1 and together desorb some of the refrigerant from the adsorbent in the second secondary adsorber chamber 410. The desorbed refrigerant flows to the secondary condenser 414 as indicated by the arrow 436 which condenses the refrigerant and dissipates heat Q_SC438. The condensed refrigerant then flows from the secondary condenser 414 to the evaporator 402, as indicated by the arrow 440. The heat Q_SC438 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

Referring now to the reverse cycle illustrated in FIG. 4B, some of the refrigerant vaporizes in the evaporator 402 thereby absorbing heat Q_E416 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the second secondary adsorber chamber (SAC2) 410, as indicated by the arrow 418, and the vaporized refrigerant is adsorbed into the adsorbent contained in the second secondary adsorber chamber 410, thereby dissipating heat Q_SA420. Additionally, more of the refrigerant vaporizes in the evaporator 402 thereby absorbing heat Q_E416 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the second primary adsorber chamber (PAC2) 406, as indicated by the arrow 422, and the vaporized refrigerant is adsorbed into the adsorbent contained in the second primary adsorber chamber 406, thereby dissipating heat Q_PA424. The heat Q_SA420 and the heat Q_PA424 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

The refrigerant adsorbed into the second secondary adsorber chamber 410 and the second primary adsorber chamber 406 originated from the first secondary adsorber chamber (SAC1) 408 and the first primary adsorber chamber (PAC1) 404, respectively. Some of the refrigerant is desorbed from the first primary adsorber chamber 404. Heat Q_P426 is supplied into the first primary adsorber chamber 404 from the exhaust system 108 shown in FIG. 1 and the heat Q_P426 desorbs some of the refrigerant from the adsorbent in the first primary adsorber chamber 404. The desorbed refrigerant flows to the primary condenser 412 as indicated by the arrow 428 which condenses the refrigerant and dissipates heat Q_PC430. The condensed refrigerant flows from the primary condenser 412 to the secondary condenser 414, as indicated by the arrow 432.

Likewise, some of the refrigerant is desorbed from the first secondary adsorber chamber 408. The heat Q_PC430 is supplied to the first secondary adsorber chamber 408 along with the heat Q_CS434 from the cooling system 110 shown in FIG. 1 and together desorb some of the refrigerant from the adsorbent in the first secondary adsorber chamber 408. The desorbed refrigerant flows to the secondary condenser 414 as indicated by the arrow 436 which condenses the refrigerant and dissipates heat Q_SC438. The condensed refrigerant then flows from the secondary condenser 414 to the evaporator 402, as indicated by the arrow 440. The heat Q_SC438 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

Referring now to FIGS. 5A and 5B, there is shown, collectively, a simplified model of a multi-effect adsorption system 500 according to an example of the invention. FIG. 5A shows the forward cycle while FIG. 5B shows the reverse cycle. Some components in the multi-effect adsorption system 500 function as desorbers in the forward cycle and then function as adsorbers in the reverse cycle. As a consequence, some items in FIGS. 5A and 5B are located in different positions in the simplified model. The multi-effect adsorption system 500 operates according to a reversible process, a forward cycle and a reverse cycle, each of which provides cooling by removing heat in an evaporator 502. FIG. 5A shows the forward cycle while FIG. 5B shows the reverse cycle. The multi-effect adsorption system 500 is a double-effect single-condenser adsorption system and includes an evaporator 502, a first primary adsorber chamber (PAC1) 504, a second primary adsorber chamber (PAC2) 506 (also known as the primary desorber 112 shown in FIG. 1), a first secondary adsorber chamber (SAC1) 508, a second secondary adsorber chamber (SAC2) 510 (also known as a secondary desorber 114 shown in FIG. 1), and a condenser 512. In general, adsorption systems use a refrigerant and an adsorbent. For example, an adsorption system may use water and silica gel or Kansi carbon combinations.

In the multi-effect adsorption system 500, the first primary adsorber chamber (PAC1) 504 and the second primary adsorber chamber (PAC2) 506 may be formed as two separate chambers arranged in such a manner as to transfer heat between one another. Similarly, the first secondary adsorber chamber (SAC1) 508 and the second secondary adsorber chamber (SAC2) 510 may be formed as two separate chambers arranged in such a manner as to transfer heat between one another.

Referring now to the forward cycle illustrated in FIG. 5A, some of the refrigerant vaporizes in the evaporator 502 thereby absorbing heat Q_E514 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the first secondary adsorber chamber 508, as indicated by the arrow 516, and the vaporized refrigerant is adsorbed into the adsorbent contained in the first secondary adsorber chamber 508, thereby dissipating heat Q_SA518. The heat Q_SA518 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1. Additionally, more of the refrigerant vaporizes in the evaporator 502 thereby absorbing heat Q_E514 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the first primary adsorber chamber 504, as indicated by the arrow 520, and the vaporized refrigerant is adsorbed into the adsorbent contained in the first primary adsorber chamber 504, thereby dissipating heat Q_PA522.

The refrigerant adsorbed into the first secondary adsorber chamber 508 and the first primary adsorber chamber 504 originated from the second secondary adsorber chamber 510 and the second primary adsorber chamber 506, respectively. Some of the refrigerant is desorbed from the second primary adsorber chamber 506. Heat Q_P524 is supplied into the second primary adsorber chamber 506 from the exhaust system 108 shown in FIG. 1 and the heat Q_P524 desorbs some of the refrigerant from the adsorbent in the second primary adsorber chamber 506. The desorbed refrigerant flows to the condenser 512 as indicated by the arrow 526 which condenses the refrigerant and dissipates heat Q_C528.

Likewise, some of the refrigerant is desorbed from the second secondary adsorber chamber 510. The heat Q_PA522 is supplied to the second secondary adsorber chamber 510 along with the heat Q_CS530 from the cooling system 110 shown in FIG. 1 and together desorb some of the refrigerant from the adsorbent in the second secondary adsorber chamber 510. The desorbed refrigerant flows to the condenser 512 as indicated by the arrow 532 which condenses the refrigerant and dissipates heat Q_C528. The condensed refrigerant then flows from the condenser 512 to the evaporator 502, as indicated by the arrow 534. The heat Q_C528 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

Referring now to the reverse cycle illustrated in FIG. 5B, some of the refrigerant vaporizes in the evaporator 502 thereby absorbing heat Q_E514 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the second secondary adsorber chamber 510, as indicated by the arrow 516, and the vaporized refrigerant is adsorbed into the adsorbent contained in the second secondary adsorber chamber 510, thereby dissipating the heat Q_SA518. The heat Q_SA518 may be dissipated to the environment through heat exchanger 136 shown in FIG. 1. Additionally, more of the refrigerant vaporizes in the evaporator 502 thereby absorbing heat Q_E514 from, for instance, cooling fluid heated by heat dissipated from the cooled area 106 shown in FIG. 1. The vaporized refrigerant flows to the second primary adsorber chamber 506, as indicated by the arrow 520, and the vaporized refrigerant is adsorbed into the adsorbent contained in the second primary adsorber chamber 506, thereby dissipating the heat Q_PA522.

The refrigerant adsorbed into the second secondary adsorber chamber 510 and the second primary adsorber chamber 506 originated from the first secondary adsorber chamber 508 and the first primary adsorber chamber 504, respectively. Some of the refrigerant is desorbed from the first primary adsorber chamber 504. Heat Q_P524 is supplied into the first primary adsorber chamber 504 from the exhaust system 108 shown in FIG. 1 and the heat Q_P524 desorbs some of the refrigerant from the adsorbent in the first primary adsorber chamber 504. The desorbed refrigerant flows to the condenser 512 as indicated by the arrow 526 which condenses the refrigerant and dissipates heat Q_C528.

Likewise, some of the refrigerant is desorbed from the first secondary adsorber chamber 508. The heat Q_PA522 is supplied to the first secondary adsorber chamber 508 along with the heat Q_CS530 from the cooling system 110 shown in FIG. 1 and together desorb some of the refrigerant from the adsorbent in the first secondary adsorber chamber 508. The desorbed refrigerant flows to the condenser 512 as indicated by the arrow 532 which condenses the refrigerant and dissipates heat Q_C528. The condensed refrigerant then flows to the evaporator 502, as indicated by the arrow 534. The heat Q_C528 may be dissipated to the environment through the heat exchanger 136 shown in FIG. 1.

FIG. 6 shows a flow diagram of an operational mode 600 depicting a manner in which a multi-effect cooling system may be implemented in accordance with an example of the invention. The following description of the operational mode 600 is made with reference to the block diagram 100 illustrated in FIG. 1, and thus makes reference to the elements cited therein. The following description of the operational mode 600 is one manner in which the multi-effect cooling system 104 may be implemented. In this respect, it is to be understood that the following description of the operational mode 600 is but one manner of a variety of different manners in which such a multi-effect cooling system 104 may be operated.

In the operational mode 600, the multi-effect cooling system 104 is operated utilizing heat from the engine 102. The exhaust system 108 heats the primary desorber 112 at step 602. The cooling system 110 heats the secondary desorber 114 at step 604. Manners in which heat from the engine 102 may be transferred to the multi-effect cooling system 104 are described in greater detail with respect to FIG. 1. In addition, the exhaust system 108 and the cooling system 110 provide substantially all of the power used to operate the multi-effect cooling system 104.

FIG. 7 shows a flow diagram of an operational mode 700 depicting a manner in which a multi-effect cooling system may be implemented according to an example of the invention. The following description of the operational mode 700 is made with reference to the block diagram 100 and schematic illustration 200 illustrated in FIGS. 1 and 2, respectively, and thus makes reference to the elements cited therein. The following description of the operational mode 700 is one manner in which the multi-effect cooling system may be implemented. In this respect, it is to be understood that the following description of the operational mode 700 is but one manner of a variety of different manners in which such a multi-effect cooling system 104 may be operated.

In the operational mode 700, the exhaust system 108 of the engine 102 heats the primary generator 208 of the multi-effect absorption system 200 at step 702. The heat Q_P230 provides the primary source of energy to the multi-effect absorption system 200 for cooling the cooled area 106. The cooling system 110 of the engine 102 heats the secondary generator 206 of the multi-effect absorption system 200 at step 704. The heat Q_CS244 provides a secondary source of energy to the multi-effect absorption system 200. Additionally, heat dissipated by the primary condenser 210 may be collected at step 706. The collected heat may then be transferred to the secondary generator 206 to provide an additional source of energy to the multi-effect absorption system 200 at step 708. The heat may be collected and transferred in a variety of manners including, but not limited to, using heat pipes and/or thermosiphons (not shown) to collect and transfer heat from the primary condenser 210 to the secondary generator 206. For example, an evaporator of the heat pipe or thermosiphon may be wrapped around the primary condenser 210 while a condenser of the heat pipe or thermosiphon may be wrapped around the secondary generator 206.

In any respect, during operation of the multi-effect absorption system 200, both the secondary condenser 212 and the absorber 204 produce heat Q_SC248 and heat Q_A220, respectively, which may be dissipated to the environment in a variety of manners. For instance, the heat exchanger 136 may disperse the heat Q_SC248 and/or the heat Q_A220 to the environment using air moving relative to the vehicle 100 having the engine 102 at step 710. Step 710 may be implemented if the vehicle is a ship, automobile, train, airplane, or any other mobile vehicle. In another example, the heat exchanger 136 may disperse the heat Q_SC248 and/or heat Q_A220 to the environment using water in contact with the vehicle 100 having the engine 102 at step 712. Step 712 may be implemented if the vehicle is a ship, submarine, amphibious vehicle, or any other vehicle which moves in an aquatic environment. In another example, heat Q_SC248 and heat Q_A220 may be converted into electricity using a pyroelectric device at step 714, in manners as described herein above with respect to the heat exchanger 136.

FIG. 8 shows a flow diagram of an operational mode 800 depicting a manner in which a multi-effect cooling system may be implemented in accordance with an example of the invention. The following description of the operational mode 800 is made with reference to the block diagram 100 and schematic illustration 300 illustrated in FIGS. 1 and 3, respectively, and thus makes reference to the elements cited therein. The following description of the operational mode 800 is one manner in which the multi-effect cooling system 104 may be implemented. In this respect, it is to be understood that the following description of the operational mode 800 is but one manner of a variety of different manners in which such a multi-effect cooling system may be operated.

In the operational mode 800, the exhaust system 108 of the engine 102 heats the primary generator 310 of the multi-effect absorption system 300 at step 802. The heat Q_P322 provides the primary source of energy to the multi-effect absorption system 300 for cooling the cooled area 106. The cooling system 110 of the engine 102 heats the secondary generator 308 of the multi-effect absorption system 300 at step 704. The heat Q_CS340 provides a secondary source of energy to the multi-effect absorption system 300. Additionally, heat dissipated by the primary absorber 306 may be collected at step 806. The collected heat may then be transferred to the secondary generator 308 to provide an additional source of energy to the multi-effect absorption system 300 at step 808. The heat may be collected and transferred in a variety of manners including, but not limited to, using heat pipes and/or thermosiphons (not shown) to collect and transfer heat from the primary absorber 306 to the secondary generator 308. For example, an evaporator of the heat pipe or thermosiphon may be wrapped around the primary absorber 306 while a condenser of the heat pipe or thermosiphon may be wrapped around the secondary generator 308.

In any regard, during operation of the multi-effect absorption system 300, both the condenser 312 and the secondary absorber 318 produce heat Q_C348 and heat Q_SA318, respectively, which may be dissipated to the environment in a variety of manners. For instance, the heat exchanger 136 may disperse the heat Q_C348 and/or the heat Q_SA318 to the environment using air moving relative to the vehicle 100 having the engine 102 at step 810. Step 810 may be implemented if the vehicle is a ship, automobile, train, airplane, or any other mobile vehicle. In another example, the heat exchanger 136 may disperse the heat Q_C348 and/or heat Q_SA318 to the environment using water in contact with the vehicle 100 having the engine 102 at step 812. Step 812 may be implemented if the vehicle is a ship, submarine, amphibious vehicle, or any other vehicle which moves in an aquatic environment. In another example, heat Q_C348 and heat Q_SA318 may be converted into electricity using a pyroelectric device at step 814.

FIG. 9 shows a flow diagram of an operational mode 900 depicting a manner in which a multi-effect cooling system may be implemented according to an example of the invention. The following description of the operational mode 900 is made with reference to the block diagram 100 and schematic illustration 400 illustrated in FIGS. 1 and 4A-4B, respectively, and thus makes reference to the elements cited therein. The following description of the operational mode 900 is one manner in which the multi-effect cooling system 104 may be implemented. In this respect, it is to be understood that the following description of the operational mode 900 is but one manner of a variety of different manners in which such a multi-effect cooling system 104 may be operated.

In the operational mode 900, the exhaust system 108 of the engine 102 heats the second primary adsorber chamber 406 of the multi-effect adsorption system 400 at step 902. The heat Q_P426 provides the primary source of energy to the multi-effect adsorption system 400 for cooling the cooled area 106. The cooling system 110 of the engine 102 heats the second secondary adsorber chamber 410 of the multi-effect adsorption system 400 at step 904. The heat Q_CS434 provides a secondary source of energy to the multi-effect adsorption system 400. Additionally, heat dissipated by the primary condenser 412 may be collected at step 906. The collected heat may then be transferred to the second secondary adsorber chamber 410 to provide an additional source of energy to the multi-effect adsorption system 400 at step 908. The heat may be collected and transferred in a variety of manners including, but not limited to, using heat pipes and/or thermosiphons to collect and transfer heat from the primary condenser 412 to the secondary adsorber chamber 410. For example, an evaporator of the heat pipe or thermosiphon may be wrapped around the primary condenser 412 while a condenser of the heat pipe or thermosiphon may be wrapped around the secondary adsorber chamber 410.

In any respect, during operation of the multi-effect adsorption system 400, the secondary condenser 438, the first secondary adsorber chamber 408, and the first primary adsorber chamber 404 produce heat Q_SC438, heat Q_SA420, and heat Q_PA424, respectively, which may be dissipated to the environment in a variety of manners. For instance, the heat exchanger 136 may disperse the heat Q_SC438, the heat Q_SA420, and/or the heat Q_PA424 to the environment using air moving relative to the vehicle 100 having the engine 102 at step 910. Step 910 may be implemented if the vehicle is a ship, automobile, train, airplane, or any other mobile vehicle. In another example, the heat exchanger 136 may disperse the heat Q_SC438, the heat Q_SA420, and/or the heat Q_PA424 to the environment using water in contact with the vehicle 100 having the engine 102 at step 912. Step 912 may be implemented if the vehicle is a ship, submarine, amphibious vehicle, or any other vehicle which moves in an aquatic environment. In another example, heat Q_SA420 and heat Q_PA424 may be converted into electricity using a pyroelectric device at step 914.

FIG. 10 shows a flow diagram of an operational mode 1000 depicting a manner in which a multi-effect cooling system may be implemented according to an example of the invention. The following description of the operational mode 1000 is made with reference to the block diagram 100 and schematic illustration 500 illustrated in FIGS. 1 and 5A-5B, respectively, and thus makes reference to the elements cited therein. The following description of the operational mode 1000 is one manner in which the multi-effect cooling system 104 may be implemented. In this respect, it is to be understood that the following description of the operational mode 1000 is but one manner of a variety of different manners in which such a multi-effect cooling system 104 may be operated.

In the operational mode 1000, the exhaust system 108 of the engine 102 heats the second primary adsorber chamber 506 of the multi-effect adsorption system 500 at step 1002. The heat Q_P524 provides the primary source of energy to the multi-effect adsorption system 500 for cooling the cooled area 106. The cooling system 110 of the engine 102 heats the second secondary adsorber chamber 510 of the multi-effect adsorption system 500 at step 1004. The heat Q_CS530 provides a secondary source of energy to the multi-effect adsorption system 500. Additionally, heat dissipated by the first primary adsorber chamber 504 may be collected at step 1006. The collected heat may then be transferred to the second secondary adsorber chamber 510 to provide an additional source of energy to the multi-effect adsorption system 500 at step 1008. The heat may be collected and transferred in a variety of manners including, but not limited to, using heat pipes and/or thermosiphons to collect and transfer heat from the first primary adsorber chamber 504 to the second secondary adsorber chamber 510. For example, an evaporator of the heat pipe or thermosiphon may be wrapped around the primary absorber chamber 504 while a condenser of the heat pipe or thermosiphon may be wrapped around the secondary adsorber chamber 510.

In any respect, during operation of the multi-effect adsorption system 500, the condenser 528 and the first secondary adsorber chamber 508 produce heat Q_C528 and heat Q_SA518, respectively, which may be dissipated to the environment in a variety of manners. For instance, the heat exchanger 136 may disperse the heat Q_C528 and/or the heat Q_SA518 to the environment using air moving relative to the vehicle 100 having the engine 102 at step 1010. Step 1010 may be implemented if the vehicle is a ship, automobile, train, airplane, or any other mobile vehicle. In another example, the heat exchanger 136 may disperse the heat Q_C528 and/or the heat Q_SA518 to the environment using water in contact with the vehicle 100 having the engine 102 at step 1012. Step 1012 may be implemented if the vehicle is a ship, submarine, amphibious vehicle, or any other vehicle which moves in an aquatic environment. In another example, heat Q_C528 and heat Q_SA518 may be converted into electricity using a pyroelectric device at step 1014.

The steps illustrated in the operational modes 600, 700, 800, 900, and 1000 may be implemented manually or automatically. For instance, in a manual operation, a user of the multi-effect cooling system 104 may open or close valves that route exhaust gases and/or cooling fluid to the desorbers thus providing the desorbers with energy to operate. In an automatic implementation, valves may be controlled by a control system. Additionally, the control system may contain a utility, program, subprogram, in any desired computer accessible medium. Furthermore, the operational modes 600, 700, 800, 900, and 1000 may be embodied by a computer program, which can exist in a variety of forms both active and inactive. For example, they can exist as software program(s) comprised of program instructions in source code, object code, executable code or other formats. Any of the above can be embodied on a computer readable medium, which include storage devices and signals, in compressed or uncompressed form.

Examples of suitable computer readable storage devices include conventional computer system RAM (random access memory), ROM (read only memory), EPROM (erasable, programmable ROM), EEPROM (electrically erasable, programmable ROM), and magnetic or optical disks or tapes. Examples of computer readable signals, whether modulated using a carrier or not, are signals that a computer system hosting or running the computer program can be configured to access, including signals downloaded through the Internet or other networks. Concrete examples of the foregoing include distribution of the programs on a CD ROM or via Internet download. In a sense, the Internet itself, as an abstract entity, is a computer readable medium. The same is true of computer networks in general. It is therefore to be understood that those functions enumerated below may be performed by any electronic device capable of executing the above-described functions.

As described hereinabove, the amount of heat supplied to the primary desorber 112 may be reduced based upon the amount of heat supplied to the secondary desorber 114. Thus, for instance, if a greater volume or higher temperature heat is supplied to the secondary desorber 114, the amount of heat supplied from the exhaust system 108 may be relatively reduced, reducing the pressure in the exhaust system 108 of the engine 102 and thereby increasing efficiency of the engine 102. Additionally, efficiency of the multi-effect cooling system 104 increases because of the increase in the coefficient of performance due to the use of heat from the cooling system 110 of the engine 102.

For instance, an improvement to the coefficient of performance is obtained from the arrangements described above. The coefficient of performance of a multi-effect cooling system may be given by the following equation:
$COP = \frac{EvaporatorHeatLoad}{GeneratorHeatLoad} = \frac{Q_{E}}{Q_{P}}$

Typically, Q_CSis zero in multi-effect cycles because the heat requirement in the secondary desorber is fulfilled by Q_X, heat obtained from another component. This leads to higher coefficients of performance compared to single effect cooling cycles.

By virtue of the arrangements described herein above, additional Q_CSfrom the cooling system 110 can reduce the Q_Pconsumed by the cycle without changing the delivered cooling (that is, Q_E). In one respect, because any reduction in Q_Pwill improve the COP, as shown in the equation above, the COP may be improved with the additional Q_CSfrom the cooling system 110 of the engine. This change may improve the COP by as much as 100%. Therefore, according to embodiments of the invention the COP of a multi-effect cooling system may be improved.

Additionally, the second law efficiency is improved from the arrangements shown above. The second law efficiency (η_II) is defined as a ratio of actual work (W) over the available work (W_max). The available work is defined as a product of the heat added to the system and the Carnot efficiency. In embodiments of the invention, the available work is the total power supplied by the engine 102 for cooling the cooled area 106.
$η_{II} = \frac{W}{W_{\max}} = 1 - \frac{W_{lost}}{W_{\max}}$

In addition, the lost work (W_lost) is the heat rejected to the environment times the Carnot efficiency.
$W_{lost} = Q η_{carnot} = Q (1 - \frac{T_{o}}{T_{exhaust}})$

- where T_ois the ambient temperature.

Any utilization of heat (Q_CS) for cooling of the cooled area 106 reduces the W_lostsignificantly and generally improves the second law efficiency of multi-effect cooling systems.

By virtue of certain examples, heat generated through operation of an engine may be supplied to a multi-effect cooling system, either absorption or adsorption types, to cool cooling fluid delivered to a cooled area. In one regard, the heat Q_CScollected from the cooling system of the engine, reduces the amount of energy used by the engine to cool itself. The reduction increases the efficiency of the engine. A dual efficiency increase may be obtained though implementation of examples of the multi-effect cooling systems described herein.

What has been described and illustrated herein are examples of multi-effect cooling systems along with some of variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the examples, which are intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated.

Multi-effect cooling system utilizing heat from an engine

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