WO2020242401A1

WO2020242401A1 - Absorption heating and cooling system with increased energy efficiency

Info

Publication number: WO2020242401A1
Application number: PCT/TR2019/050404
Authority: WO
Inventors: Murat İŞLER
Original assignee: Maxeff Teknoloji̇ Anoni̇m Şi̇rketi̇
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2020-12-03

Abstract

The invention is related to the working fluids which consists of at least one refrigerant and at least one sorbet; can be at solid-liquid, liquid-liquid or gas-liquid phase, can be decomposed according to the extraction principle by exhibiting upper critical solution temperature (UCST) or lower critical solution temperature (LCST) and the absorption heating cooling cycles and systems where these fluids are used in order to increase the energy efficiency in the absorption heating cooling systems.

Description

DESCRIPTION

Absorption Heating and Cooling System with Increased Energy Efficiency

Technical Field

The invention relates to an absorption heating and cooling systems.

The invention is particularly related to an absorption heating and cooling system which comprises usage of working fluids that exhibit upper critical solution temperature (UCST) and lower critical solution temperature (LCST) behavior and decomposition thereof according to the extraction principal; wherein the energy consumed per unit cooling is decreased, energy efficiency is increased.

Prior Art

Today due to the continuous improvement of technology, although different approaches come into existence in the systems such as heating and cooling, conventional systems are widely used. Along with the usage of conventional boiler systems in general, there are also systems such as heat pump. When we consider the cooling systems in general, steam compression cycles and absorption or adsorption systems are currently used. In these systems, the energy consumed per unit heating or cooling is relatively high.

The energy consumption issue is one of the main problems for all countries in the world. Parallel to the increase of the population and the industrialization day by day, also the energy consumption increases. In addition to the increasing energy costs today, when we consider the global warming and carbon release values, using energy efficiently shall be evaluated not only in terms of electrical costs but also in terms of its effects to the environment. In order to enable using current energy sources more efficiently, systems that enable high energy efficiency are required.

In the absorption cooling and heating systems within the present state of the art, for decomposing the cooling fluid and the absorbent (sorbent) from each other and purifying the cooling fluid, generally distillation systems in other words systems in which the cooling fluid is evaporated and condensed again, are seen, also there are trials with membrane type decomposition. The energy consumption of these systems is relatively high.

An exemplary absorption cooling system flow within the present state of the art is as follows; the refrigerant at the low pressure gas phase evaporated in the evaporator passes to the sorber, the refrigerant is cooled by means of the high concentration refrigerant sorbent mixture which comes after losing its heat in the exchanger that it had previously in the sorber, condensation is realized during absorption and the refrigerant condensates and thus transmits the energy on it through the cooling tower into the tower water. The concentration of the high concentration refrigerant sorbent mixture decreases by the absorbed refrigerant and thus becomes a low concentration refrigerant sorbent mixture and is directed from the sorber to the exchanger by means of the pump. The low concentration refrigerant sorbent mixture which is slightly heated by passing through the heat recovery system exchanger enters into the boiler. The low concentration refrigerant sorbent mixture is heated in the boiler with the heat coming from the heat source and while an amount of refrigerant is evaporated and directed to the condenser, low concentration refrigerant sorbent mixture that has decreased refrigerant becomes a high concentration refrigerant sorbent mixture and thus exits from the generator and goes to the heat recovery exchanger. The refrigerant which is condensed within the condenser unit liquefies and transmits the gasification enthalpy to the coming water through the cooling tower. Liquid form refrigerant goes to the evaporator after passing though the expansion valve. It is evaporated in the evaporator by means of taking heat and the cycle is completed.

In the absorption cooling systems in the present state of the art, although there are many fluid pairs in the cycle as a working fluid, in the recent years in practice Ammonia (NH3)- Water and Water-Lithium Bromide (LiBr) pairs are used. In the present state of the art, the two working fluids are decomposed from each other by the distillation method by benefiting from the boiling point differences in the boiler. In small cooling capacity low temperature (up to -40Ό) applications, ammonia-water pair is used. Here ammonia is used as a cooling fluid; water is used as an absorbent. In Water-Lithium Bromide (LiBr) pairs, water is used as a cooling fluid, and the Lithium Bromide (LiBr) is used as an absorbent. In the Water-Lithium Bromide (LiBr) pairs, because water is used as the cooling fluid, reaching OO is very difficult. In such systems, generally the water in the evaporator is evaporated under vacuum at 4 Ό and the water that is required to be cooled can be cooled to 6-7T! according to the requirement of the application. These types of absorption cooling systems produce cold water for industrial processes and central air conditioning systems.

One of the patents encountered in the literature as a result of the research made is the application of the patent No TR2010/07984. The subject of the invention is related to an energy cycle system which has a multistage absorption cooling machine or absorption heat pump. All of the multi stage absorption machines have at least one high pressure generator wherein the cooling substance at the highest temperature level that exit out of the machine is extracted from the sorbent substance, at least one intermediate pressure generator wherein again cooling substance is extracted from the sorbent substance and herein the intermediate pressure generator is operated by means of the condensation heat of the steam of the cooling substance extracted from the high pressure generator. This heat transfer is performed by means of a first thermic connection unit, the additional drive heat at the intermediate temperature level or a few drive heats having different average temperature level are connected to the first thermic connection unit by means of a second thermic connection unit.

In the patent document with publication No TR 2004/03065, in absorption cooling system wherein the lithium bromide-water pair is used, instead of using a sole solution heat exchanger that has a major heat exchange area, a small capacity heat exchanger that has the same heat exchange area in total and an absorber and two different heat exchangers named as pre cooling are used. However, since said system is only directed to cooling, it may not be possible to obtain a system which operates both as a cooler and as a heater with the developed method.

The energy consumption and installation costs or the absorption cooling systems within the present state of the art is relatively high. Also, they have a complex structure and they take a large space due to their volume. In said systems, in order to develop the performance of cooling, studies based on condensation heat recovery, absorption heat recovery, absorption/condensation heat recovery and increasing evaporator heat amount are made. However, solutions for reducing the energy consumed in total during the cycle of the system are not encountered.

As a result, due to the abovementioned disadvantages and the insufficiency of the current solutions in terms of the subject, an improvement is required to be made in the relevant technical field.

Brief Description of the Invention

The present invention is related to an absorption heating and cooling system with increased energy efficiency, which fulfills the abovementioned requirements, eliminates all disadvantages and brings some additional advantages.

The prior aim of the invention; is to enable the usage of working fluids which consists of mixture of at least one refrigerant and at least one sorbent; are decomposed according to the extraction principal by exhibiting upper critical solution temperature (UCST) or lower critical solution temperature (LCST) behavior at so I id- liquid, liquid-liquid or gas-liquid phase, in order to increase the energy efficiency in the absorption heating cooling systems.

Another aim of the invention; is to enable an absorption heating and cooling system wherein working fluid that exhibit UCST and LCST behavior are used and decomposed according to the extraction principle; thus, the energy consumed per unit cooling is reduced; energy efficiency is increased.

Another aim of the invention; is to enable an absorption heating and cooling system which is sensitive against the environment by decreasing carbon release as a result of increasing the energy efficiency.

Another aim of the invention; is to enable an absorption heating and cooling system which enables to decrease energy costs and economic gain as a result of increasing the energy efficiency.

In order to fulfill the abovementioned aims; the invention involves working fluids which consists of mixture of at least one refrigerant and at least one sorbent; are decomposed according to the extraction principal by exhibiting upper critical solution temperature (UCST) or lower critical solution temperature (LCST) behavior at solid-liquid, liquid-liquid or gas-liquid phase; in order to be used in the absorption heating and cooling systems for increasing the energy efficiency. Preferably said working fluid is selected from the group that consists of Methanol-Nonane, Methanol-Octane, Phenol-Water, [Hbet][Tf₂N]-water.

In order to fulfill the abovementioned aims; the invention comprises an absorption heating and cooling cycle method wherein abovementioned working fluid is used, comprising the process steps of; providing cooling by evaporating at least one refrigerant and transforming into a gas refrigerant; providing heating by means of absorbing at least one gas refrigerant with at least one sorbent and transforming into a low concentration working fluid; decomposing said low concentration working fluid as a liquid refrigerant and at least one sorbent by means of bringing to the upper critical solution temperature (UCST) or lower critical solution temperature (LCST).

In order to fulfill the abovementioned aims; the invention comprises an absorption heating and cooling system wherein abovementioned cycle method is used comprising; at least one evaporator wherein at least one liquid refrigerant is evaporated by receiving heat from the environment and thus the cooling is provided;

at least one sorber wherein at least one has refrigerant is condensed after being absorbed by at least one sorbent, thus heating is enabled by means of the heat transmitted to the environment; at least one temperature regulator wherein the low concentration working fluid which exits from said sorber is brought to the upper critical solution temperature (UCST) or lower critical solution temperature (LCST); and at least one decomposition unit wherein the low concentration working fluid at critical temperature is decomposed as a liquid refrigerant and sorbent.

An exemplary embodiment comprises; at least one heat recovery exchanger which is parallel connected to the low concentration working fluid line that exit out of the sorber; is connected between the low concentration working fluid line that exit out of the sorber and the sorbent line that exits out of the decomposition unit and enables heat transfer between two lines and at least one heat recovery exchanger which is connected between the low concentration working fluid line that exit out of the sorber and the liquid refrigerant line that exit out of the decomposition unit and enables heat transfer between the two lines. The exemplary embodiment also comprises at least one pump which increases the pressure of the low concentration working fluid that exits out of the sorber; at least one mechanical power recovery unit which enables recovery of the excessive pressure on the decomposed sorbent or liquid refrigerant in the decomposition unit.

Another exemplary embodiment comprises at least one first heat recovery exchanger which is serially connected to the low concentration working fluid line that exits out of the sorber; is connected between the low concentration working fluid that exits out of the sorber and the liquid refrigerant line that exits out of the decomposition unit and enables transfer between the two lines and at least one second heat recovery exchanger which is connected between the low concentration working fluid line that exits our of said first heat recovery exchanger and the sorbent line that exits out of the decomposition unit and enables heat transfer between the two lines.

Another exemplary embodiment comprises; at least one first heat recovery exchanger which is serially connected to the low concentration working fluid line that exits out of the sorber; is connected between the low concentration working fluid that exits out of the sorber and the sorbent line that exits out of the decomposition unit and enables transfer between the two lines and at least one second heat exchanger which is connected between low concentration working fluid line that exits out of said first heat recovery exchanger and the liquid refrigerant line that exits out of the decomposition unit and enables heat transfer between the two lines.

The structural and characteristic features of the present invention will be understood clearly by the following drawings and the detailed description made with reference to these drawings and therefore the evaluation shall be made by taking these figures and the detailed description into consideration.

Figures Clarifying the Invention

In order to understand the present invention in a best manner with its structure and additional elements, it shall be evaluated with the following described figures.

Figure-1 is a schematic view of the closed cycle within the absorption heating cooling system.

Figure-2 is a schematic view of an alternative embodiment which includes parallel connected exchangers within the absorption heating cooling system.

Figure-3 is a schematic view of an alternative embodiment which includes serial connected exchangers within the absorption heating cooling system.

Figure-4 is a schematic view of an alternative embodiment which includes serial connected exchangers within the absorption heating cooling system.

Figure-5 is a schematic view of an alternative embodiment which includes pump and mechanic recovery unit within the absorption heating cooling system.

Figure-6 is a liquid-liquid equilibrium phase diagram of the working fluid which consists of Methanol-Nonane mixture used in one embodiment of the invention. Methanol: CFUO Nonane: C9FI20

Figure-7 is a liquid-liquid equilibrium phase diagram of the working fluid which consists of Methanol-Octane mixture used in one embodiment of the invention. Methanol: CFUO Octane:

OdH_ΐd

Figure-8 is a liquid-liquid equilibrium phase diagram of the working fluid which consists of Phenol-Water mixture used in one embodiment of the invention.

Figure-9 is a liquid-liquid equilibrium phase diagram of the working fluid which consists of [Hbet][Tf2N]-Water mixture used in one embodiment of the invention. Description of the References

100- Absorption heating cooling system

101 - Sorber

102- Decomposition unit

103- Evaporator

104- Low concentration working fluid (refrigerant sorbent solution)

105- Sorbent (or high concentration working fluid)

106- Liquid refrigerant

107- Gas refrigerant

108- Temperature regulator

109- Exchanger

1 10- Pump

1 1 1 -Mechanical recovery unit

Q- Heat

Detailed Description of the Invention

In this detailed description the absorption heating and cooling system with increased energy efficiency subject to the invention is only described for clarifying the subject matter and in a non-limiting manner.

The invention is related to an absorption heating and cooling system resists to the usage of working fluids which exhibits upper critical solution temperature and lower critical solution temperature, and decomposition of them according to extraction principle; thus, the energy consumed per unit cooling is reduced, energy efficiency is increased.

The critical temperature expresses the temperature in which two substances in solid-liquid, liquid-liquid or gas-liquid phase that can be mixed under normal conditions can be fully mixed in a manner to form a homogenous when the temperature increases or in some cases decreases.

The critical temperature expresses the temperature which shows variety according to the mixture concentration and is required for bringing two substances in solid-liquid, liquid-liquid or gas-liquid phase into one phase by mixing totally to each other. Critical temperature is a limit temperature; the mixtures can be dissolved at higher temperatures or lower temperatures than the critical temperature according to the behaviors of the liquids.

In case one of the mixtures is polymer (solid), critical temperature expresses the temperature wherein the bond between the substances subject to interaction changes instead of dissolving.

In the widest sense the critical temperature expresses the temperature which shows variety according to the concentration of mixture and causes change in the bonds between the substances.

The upper critical temperature (UCST, Upper critical solution temperature) expresses the upper temperature limit in which all component substances in a mixture (substances at solid- liquid, liquid-liquid or gas-liquid phase) can mix with each other fully. When the mixture is under the UCST temperature degree, the components establish a bond between them and mix totally with each other. When the mixture temperature increases to the UCST value then the bond structure between the components is destroyed and the components are decomposed from each other without phase change.

The lower critical temperature (LCST, Lower critical solution temperature) expresses the lower temperature limit in which all component substances in a mixture (substances at solid- liquid, liquid-liquid or gas-liquid phase) can mix with each other fully. When the mixture is over the LCST temperature degree, the components establish a bond between them and mix totally with each other. When the mixture temperature decreases to the LCST value then the bond structure between the components is destroyed and the components are decomposed from each other without phase change.

The working fluid mentioned in the invention comprises sorbent-refrigerant mixtures which exhibit UCST and/or LCST behavior in solid-liquid, liquid-liquid, gas liquid phases. In the present state of the art the working fluid used in said systems are decomposed according to the distillation principal. However, in the absorption heating cooling cycle subject to the invention; said working fluids with said phase structures, are decomposed from each other without phase change by means of the destruction of the bond structures between the components at UCST and/or LCST temperature values. Here‘refrigerant’ expresses a cooling fluid substance, is defined as the substances which enable cooling effect by means of evaporating in the absorption heating and cooling cycle.

Here sorbent expresses an absorptive-absorber substance, is defined as the substances which enable heating effect by means of cooling the refrigerant at the steam phase in the absorption heating and cooling cycle.

Here the working fluid expresses the mixture of the refrigerant and sorbent used in the absorption heating cooling systems; they are the fluid substances which perform the heat transfer in the heating cooling cycle.

The working fluid used in the cycle of the absorption heating and cooling systems included within the present state of the art; are decomposed by evaporation with the distillation principle by benefiting from the differences in the boiling points of the refrigerant and sorbent within a boiler.

Together with the invention; by usage of working fluids that exhibit UCST and/or LCST behavior; with lower energy than the required energy for the distillation in the boiler of the present state of the art, by means of the decomposition of the sorbent and the refrigerant at the critical temperature according to the extraction principal without using boiler; the energy consumed for the total cycle is decreased. Therefore, the energy consumed per unit cooling is decreased; the efficiency of the absorption heating cooling system is increased.

The important point of the invention is to use the substances as the working fluid in the absorption heating and cooling systems, whose bond structure among the substances in interaction is subject to change in different temperatures.

Together with increasing or decreasing the temperature, there are substances sensitive to temperature of which bond structure can change. These can be various polymers, ionic liquids or special mixtures. Not only mixture forming substances but also various solid, liquid and gas substances and also substances that behave in this manner can be considered within this scope. In the invention; sorbent and/or refrigerant may have said characteristic; they are enabled to be decomposed from each other by means of bringing the bond between them to the critical temperature (UCST or LCST). Based on the type of the substance used for bringing to the critical temperature (such as UCST or LCST), it is required to increase and decrease the temperature of the working fluid. Based on the operating temperatures, it may be required to heat or cool the working fluid at a temperature regulator, or it can be decomposed directly based on the operating temperature.

In the invention as the working fluid; individuals or combinations which are selected among the substances such as heat sensitive ionic liquids, polymers etc. those exhibit UCST or LCST behavior are used as refrigerant and/or sorbent. The preferred working fluids of the invention are; Methanol-Nonane, Methanol-Octane, Phenol-Water, [Hbet][Tf2N]-water mixtures.

In the Methanol-Nonane mixture used as the working fluid, methanol is selected as the refrigerant, and the nonane is selected as the sorbent; the mixture exhibits LCST behavior (Figure 6).

In the Methanol-Octane mixture used as the working fluid, methanol is selected as the refrigerant, and the octane is selected as the sorbent; the mixture exhibits LCST behavior (Figure 7).

In the Phenol-Water mixture used as the working fluid, water is selected as the refrigerant, and the phenol is selected as the sorbent; the mixture exhibits LCST behavior (Figure 8).

In one exemplary embodiment of the invention as the working fluid; mixture of 50% [Hbet][Tf2N] by weight and 50% water by weight is used. Here the water is selected as the refrigerant. [Hbet][Tf2N], betanium bis(trifluoromethylsulfonyl)imide ionic liquid is selected as the sorbent. In said embodiment, at temperatures less than 550, the working fluid which has a hydrophobic structure, passes to a hydrophilic structure at temperatures more than 550 and water and [Hbet][Tf2N] are decomposed. For said working fluid; the critical temperature for the mixture of 50% [Hbet][Tf2N] by weight and 50% water by weight is 550. The critical temperature values for different concentrations are as it is shown in Figure 9.

In the alternative embodiments of the invention, hydrophilic substances before heating and hydrophobic substances after heating to the degrees higher than the critical temperatures (LCST) can be used. The substances that exhibit such features can be used as both sorbent and refrigerant. Not only mixture forming substances but also various solid, liquid and gas substances and also substances that behave in this manner can be considered within this scope. In the invention, as the working fluid solid-fluid working fluids that exhibit UCST or LCST behavior can be used (for example polymer and liquid mixtures).

In Figure-1 , a schematic view of the closed cycle of the preferred embodiment of the absorption heating cooling system subject to the invention is seen. The invention essentially comprises at least one evaporator (103), at least one sorber (101 ), at least one temperature regulator (108); preferably it includes at least one phase decomposition unit (102).

Said evaporator (103) is the unit wherein the refrigerant (106) at the liquid phase in the cycle is evaporated by taking heat on itself thus the cooling process is performed. The cooling area is formed around the evaporator (103). Refrigerant (107) output in gas form is realized from the evaporator (103).

Said sorber (101 ); is the unit where the absorption of the refrigerant (107) in gas form within the cycle is performed by means of the sorbent (or high concentration working fluid) (105) and the heating process is performed by means of the heat given to the environment during condensation. The heating area is formed around the sorber (101 ). By means of the absorption performed in the sorber (101 ), low concentration working fluid (104) output is realized.

Said temperature regulator (108); according to the UCST or LCST behavior shown by the low concentration working fluid (104) in the cycle, is the unit wherein the working fluid is brought to the critical temperature by means of increasing or decreasing operating temperature.

Said decomposition unit (102) is the unit where the low concentration working fluid (104) which is brought to the UCST or LCST critical temperature in the temperature regulator (108) is decomposed as a sorbent (or high concentration working fluid) (105) and liquid refrigerant (106) without phase change according to the extraction principal.

The invention includes the absorption heating and cooling cycle method performed in the above defined system. The liquid refrigerant (106) which enters in the evaporator (103) in said cycles seen in Figure 1 is evaporated by means of receiving heat and exits as a gas refrigerant (107). Gas refrigerant (107) enters to the sorber (101 ). Flere it is absorbed by means of mixing with the sorbent (or high concentration working fluid) (105) fed to the sorber (101 ) and exits from the sorber (101 ) as a low concentration working fluid (refrigerant and sorbent mixture) (104). Low concentration working fluid (104) is brought to the required critical temperature (UCST or LCST) for being decomposed as a refrigerant and sorbent after entering into the temperature regulator (108). The low concentration working fluid (104) that exits from the temperature regulator (108) at the critical temperature, after entering to the decomposition unit (102); is decomposed as a sorbent (or high concentration working fluid)

(105) and liquid refrigerant (106). The decomposed liquid refrigerant (106) is again fed to the evaporator (103). The decomposed sorbent (or high concentration working fluid) (105) is again fed to the sorber (101 ). Therefore, the cycle can be completed with high energy efficiency.

In the absorption heating cooling system (100) subject to the invention, the liquid refrigerant

(106) and gas refrigerant (107) circulating within the cycle are not required to be pure, they may partially comprise sorbent (105). Since the main aim of the system is to create critical temperature difference, as long as it does not affect the proper operation of the system, it will not create any problem that the refrigerant within the cycle may include sorbent. In the most basic form of the absorption heating cooling system cycle, although circulation of the refrigerant in pure form is desired, it may be possible that this may not be realized or may not be required.

In the absorption heating cooling system (100) subject to the invention, provided that the cycle principle remains the same, the components of the system may be configured in a different manner in order to increase the efficiency. In an alternative embodiment of the invention, the evaporator (103) and the sorber (101 ) can be configured as a single unit. In a different alternative embodiment, the sorber (101 ) and the decomposition unit (102) can be configured as a single unit so that the absorption and decomposition process can be performed within one unit. In another alternative embodiment, the evaporator (103), the sorber (101 ) and the decomposition unit (102) can be found together. In a different alternative embodiment, the temperature regulator (108) and the decomposition unit (102) can be found together.

In the absorption heating cooling system subject to the invention, the alternative embodiments can include various types of pumps in order to enable the transmission of the fluids (refrigerant, sorbent or working fluid). Alternative embodiments can include different types of valves for adjusting, stopping the flow of the fluids within the system which are transferred from one place to another, starting the flow which is stopped previously or increasing the flow rate of the fluid. In alternative embodiments of the invention, the refrigerant within the cycle can be overcooled (sub-cool) with an additional cooler. In order to increase the cooling capacity in the cooling system and the efficiency overcooling, is to cool the cooling fluid (refrigerant) at the condensation point under the condensation point. In an alternative embodiment, in order to increase the efficiency, by enabling the gas refrigerant (107) receive heat from the liquid refrigerant (106), liquid refrigerant (106) can be cooled. In another alternative embodiment, sorbent (or high concentration working fluid) (105) fed to the sorber (101 ) is enabled to receive heat from the liquid refrigerant (106) thus the liquid refrigerant (106) can be cooled.

Alternative embodiments designed within the absorption heating cooling system subject to the invention can operate at different pressure and/or temperatures. In an alternative embodiment, a different component is added in addition to the liquid refrigerant (106) in the evaporator (103), the temperature of the refrigerant at the same pressure can be changed.

In the alternative embodiments designed within the absorption heating cooling system subject to the invention, various refrigerants or different refrigerant-sorbent pairs can be used in the same system.

In the absorption heating cooling system, the alternative embodiments can include at least one heat recovery exchanger (109) for increasing the efficiency. The exchanger (109) enables heat transfer between two fluids (liquid or gas) that have temperature differences between them from one to another without mixing to each other without any physical contact.

In Figure 2, there are two exchangers (109) which are parallel connected to one alternative embodiment of the absorption heating cooling system.

The low concentration working fluid (104) which exits at the critical temperature from the temperature regulator (108), enters into the decomposition unit (102); and exits as a sorbent (or high concentration working fluid) (105) and liquid refrigerant (106). The temperature herein is different from the temperature of the low concentration working fluid (refrigerant and sorbent mixture) (104) which exit out of the sorber (101 ).

In the embodiment in Figure 2, the low concentration working fluid (refrigerant and sorbent mixture) (104) which exits from the sorber (101 ), before entering into the temperature regulator (108), passes through the liquid refrigerant (106) heat recovery and sorbent (or high concentration working fluid) (105) heat recovery exchangers (109) and approximates to the required critical temperature for decomposition. Therefore, the energy to be consumed in the temperature regulator (108) is reduced and the efficiency is increased. Another benefit of the liquid refrigerant (106) heat recovery exchanger (109) is that the flash steam amount formation is reduced when the liquid refrigerant (106) enters into the low-pressure evaporator (103) by decreasing its energy. Since the flash steam ratio is reduced, the liquid ratio of the refrigerant (106) which enters into the evaporator (103) increases and the increase in the liquid ratio also increases the cooling capacity, in brief cooling performance increases. Before the sorbent (or high concentration working fluid) (105) heat recovery exchanger (109) enters in the sorber (101 ) prevents flash steam formation and an additional cooling load to the sorber (101 ) by means of cooling the sorbent (or high concentration working fluid) (105). When we consider the temperature distribution and flow rates, the most heat recovery is thought to be performed in parallel type.

In the alternative embodiments of the invention, exchangers (109) can be connected to the system in a serial manner. In the embodiment of Figure 3, the low concentration working fluid (refrigerant and sorbent mixture) (104) that exits from the sorber (101 ), before entering into the temperature regulator (108), first passes through the liquid refrigerant (106) heat recovery exchanger (109), then by passing through the sorbent (or high concentration working fluid) (105) heat recovery exchanger (109), it is approximated to the required critical temperature and enters into the temperature regulator (108). Therefore, the energy to be consumed for bringing the fluid to the critical temperature in the temperature regulator (108) can be decreased and the efficiency is increased.

In the embodiment in Figure 4, again serially connected exchangers (109) are seen. The low concentration working fluid (refrigerant and sorbent mixture) (104) which exits from the sorber (101 ), before entering into the temperature regulator (108), first of all passes through the sorbent (or high concentration working fluid) (105) heat recovery exchanger (109), then passes through the liquid refrigerant (106) heat recovery exchanger (109) and approximates to the critical temperature for decomposition and then enters into the temperature regulator (108). Therefore, the energy to be consumed for bringing the fluid to the critical temperature in the temperature exchanger (108) can be decreased and the efficiency is increased.

In the alternative embodiments of the absorption heating cooling system (100) subject to the invention, pump (1 10) and mechanical power recovery unit (1 1 1 ) can be used for the sake of improvement. An exemplary embodiment for this usage is shown in Figure 5. Ad it can be seen in the Figure, the low concentration working fluid (refrigerant sorbent solution) (104) that exits after absorption in the sorber (101 ); is decomposed in the decomposition unit (102) as sorbent (105) and liquid refrigerant (106). When this decomposition is realized, in order not to allow sorbent (105) or liquid refrigerant (106) transform into gas phase, in said alternative embodiment, low concentration working fluid (104) is pressurized by means of a pump (1 10). For this reason, after the decomposition the sorbent (105) and liquid refrigerant (106) couple which have excessive pressure on them, are particularly passed through the heat recovery exchangers (109), then through the mechanical power recovery units (1 1 1 ) and recovery of the excessive pressure on them is enabled. Here the pressures up to the inner pressure of the sorber (101 ) or the evaporator (103) are considered as excessive. Part of the energy consumed for the pump (1 10) by means of the mechanical power recovery units (1 1 1 ) is recovered. A part of the electric of the pump (1 10) can be met by means of a system similar to a turbine which is connected directly to the pump (1 10) used in the alternative embodiments.

In the alternative embodiments where solid-liquid working fluids that exhibit UCST or LCST behavior are used, filters and/or membranes can be used in the decomposition unit (102).

In the alternative embodiments, not only the number of sorbers (101 ) can be increased but also it is possible to increase the heat difference by using serial sorbers. Although steam can be produced by the sorber (101 ), also it may be possible to direct the generated steam to another sorber or system. In addition to this, instead of sorbent any kind of adsorbent (sorbent) product can be used.

In the alternative embodiments, the number of evaporators (103) can be increased and heat recovery systems can be added among the sorbers (101 ). Various numbers and types of extension valve application can be included to the system. It is possible to operate at different pressures and/or temperatures. In order to create pressure difference and control the flow rate, an extension valve can be added. In order to change the pressure of the liquid refrigerant (106), at least one extension valve to the system from the evaporator (103). A different component is added in addition to the refrigerant in the evaporator (103), the temperature of the refrigerant at the same pressure can be changed.

Claims

1- A working fluid to be used for increasing the energy efficiency in the absorption heating and cooling systems; comprising of at least one refrigerant and at least one sorbent mixture which can be decomposed by exhibiting upper critical solution temperature (UCST) or lower critical solution temperature (LCST) behavior at solid-liquid, liquid-liquid or gas-liquid phase in order.

2- The working fluid according to claim 1 , characterized in selecting from the group comprising of Methanol-Nonane, Methanol-Octane, Phenol-Water, [Hbet][Tf₂N]-water.

3- An absorption heating and cooling cycle method wherein said working fluid according to claim 1 is used, characterized in comprising the following process steps;

• Providing cooling by evaporating at least one refrigerant (106) and transforming into a gas refrigerant (107);

• providing heating by means of absorbing at least one gas refrigerant (107) with at least one sorbent (105) and transforming into a low concentration working fluid (104) ;

• Decomposing said low concentration working fluid (104) as a liquid refrigerant (106) and at least one sorbent (105) by means of bringing to the upper critical solution temperature (UCST) or lower critical solution temperature (LCST).

4- An absorption heating and cooling system (100) wherein said cycle method according to claim 3 is used comprising;

• at least one evaporator (103) wherein at least one liquid refrigerant (106) is evaporated by receiving heat from the environment and thus the cooling is provided;

• at least one sorber (101 ) wherein at least one has refrigerant (107) is condensed after being absorbed by at least one sorbent (105), thus heating is enabled by means of the heat transmitted to the environment characterized in further comprising; • at least one temperature regulator (108) wherein the low concentration working fluid (104) which exits from said sorber (101 ) is brought to the upper critical solution temperature (UCST) or lower critical solution temperature (LCST); and

• at least one decomposition unit (102) wherein the low concentration working fluid (104) at critical temperature is decomposed as a liquid refrigerant (106) and sorbent (105).

5- The system according to claim 4, characterized in further comprising at least one heat recovery exchanger (109) and/or at least one valve and/or at least one pump (1 10) and/or at least one mechanical recovery unit (1 1 1 ) in order to increase the system efficiency.

6- The system according to claim 5, characterized in comprising the following which are connected in parallel to the low concentration working fluid (104) line that exits from the sorber (101 );

• At least one heat recovery exchanger (109) which is connected between the low concentration working fluid (104) line that exits from the sorber (101 ) and the sorbent (105) line that exits from the decomposition unit (102) and enables heat transfer between the two lines and

• At least one heat recovery exchanger (109) which is connected between the low concentration working fluid (104) line that exits from the sorber (101 ) and the liquid refrigerant (106) line that exits from the decomposition unit (102) and enables heat transfer between the two lines.

7- The system according to claim 5, characterized in comprising the following;

• At least one pump (1 10) wherein the pressure of the low concentration working fluid (104) that exits from the sorber (101 ) is increased;

• At least one mechanical power recovery unit (1 1 1 ) which enables recovery of the excessive pressure on the decomposed sorbent (105) or the liquid refrigerant (106) that are decomposed in the decomposition unit (102). 8- The system according to claim 5, characterized in comprising the following which are connected in serial to the low concentration working fluid (104) line that exits from the sorber (101 );

• At least one first heat recovery exchanger (109) which is connected between the low concentration working fluid (104) line that exits from the sorber (101 ) and the liquid refrigerant (106) line that exits from the decomposition unit (102) and enables heat transfer between the two lines and

• At least one second heat recovery exchanger (109) which is connected between the low concentration working fluid (104) line that exits from said first heat recovery exchanger (109) and the sorbent (105) line that exits from the decomposition unit (102) and enables heat transfer between the two lines.

9- The system according to claim 5, characterized in comprising the following which are connected in a serial manner to the low concentration working fluid (104) line that exits from the sorber (101 );

• At least one first heat recovery exchanger (109) which is connected between the low concentration working fluid (104) line that exits from the sorber (101 ) and the sorbent (105) line that exits from the decomposition unit (102) and enables heat transfer between the two lines and

• At least one second heat recovery exchanger (109) which is connected between the low concentration working fluid (104) line that exits from said first heat recovery exchanger (109) and the liquid refrigerant (106) line that exits from the decomposition unit (102) and enables heat transfer between the two lines.