Title of Invention	ABSORPTION CHILLER-HEATER
Abstract	An absorption-chiller heater for circulating a refrigerant and an absorption solution by connecting an evaporator (6), an absorber (7), a regenerator (1, 3), and a condenser (4), capable of selecting between a cooling operation for cooling a brine with evaporation heat of the refrigerant, and a heating operation for mainly heating the brine with the condensation heat of the refrigerant, said absorption chiller-heater comprising a refrigerant liquid storage part (4A) for storing the refrigerant liquid condensed by radiating heat into the cooling water in the condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe (20A) interposing a flow control valve (V3) for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means (C) for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser.

Title of Invention

ABSORPTION CHILLER-HEATER

Abstract

An absorption-chiller heater for circulating a refrigerant and an absorption solution by connecting an evaporator (6), an absorber (7), a regenerator (1, 3), and a condenser (4), capable of selecting between a cooling operation for cooling a brine with evaporation heat of the refrigerant, and a heating operation for mainly heating the brine with the condensation heat of the refrigerant, said absorption chiller-heater comprising a refrigerant liquid storage part (4A) for storing the refrigerant liquid condensed by radiating heat into the cooling water in the condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe (20A) interposing a flow control valve (V3) for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means (C) for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser.

Full Text	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water cooler-heater. 2. Detailed Description of the Prior Art As shown in Fig. 3, it is known that an absorption chiller-heater; is constructed to be selectable between a cooling operation such as space cooling conducted in such a way that a high temperature regenerator 1 having a gas burner 2, a low temperature regenerator 3, a condenser 4, an evaporator 6, an absorber 7, a low temperature heat exchanger 9, a high temperature heat exchanger 10, an absorption solution pump 17, and a refrigerant pump 22, etc. are connected with an absorption solution pipe and a refrigerant pipe; the refrigerant vapor that has been evaporated and separated from the absorption solution heated by the high temperature regenerator 1 and low temperature regenerator 3 is transferred to the condenser 4 and cooled by the cooling water flowing within the cooling water pipe 24 to be condensed, the condensed refrigerant liquid is transferred to the evaporator 6 to be evaporated, and the cold water cooled by the evaporation heat of the refrigerant is circulated to the cooling load via a cold/hot water pipe 23, and a heating operation such as space heating conducted in such a way that the refrigerant vapor which is evaporated and separated from the absorption solution heated by the high temperature regenerator 1 and the absorption solution separated therefrom by evaporating the refrigerant are directly transferred to a cold drum 8, and the hot 1 water heated mainly by the condensation heat of the refrigerant is circulated to a heating load via a cool/hot pipe 23. Such an absorption chiller is disclosed in US 6,370,893. In the absorption chiller-heater with the aforementioned structure, a refrigerant tank 4A which stores the refrigerant liquid condensed by radiating heat into the cooling water flowing in the cooling water pipe 24 is provided inside the condenser 4 and the amount of the refrigerant liquid stored therein is determined by the magnitude of the load. Thus, when the cooling load is large, the difference in the density of the absorption solution is larger (i.e., the amount of refrigerant in the refrigerant accumulator increases), and, when the cooling load is low, the difference in the density of the refrigerant liquid is lower (i.e., the amount of refrigerant in the refrigerant accumulator decreases). Therefore, when the temperature of the cooling water is low and in low density/low load operation, sometimes the refrigerant liquid is insufficient in the evaporator 6 and a cavitation occurs in the refrigerant pump 22, resulting in damage. Moreover, when the cooling operation such as space cooling is stopped, such an operation is conducted that the on-off valve V4 is manually opened to return the refrigerant liquid stored in the evaporator 6 to the absorber 7 to dilute the absorption solution or the refrigerant liquid in the refrigerant tank 4A is returned to the absorber 7 so that the absorption solution condensed through heating does not crystallize out. 2 condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe interposing a flow control valve for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser. In a preferred embodiment, the absorption chiller-heater is characterized in that the control means has a function to open the flow control valve when heating operation. In a further embodiment, the absorption chiller-heater is characterized in that the control means has a function to open the flow control valve based on the atmospheric temperature when the cooling operation is stopped during a lower atmospheric temperature than the given temperature. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS These and other advantages of the present invention will become clear from following description with reference to the accompanying drawings, wherein : Fig. 1 is an explanatory illustration showing an embodiment of the present invention ; Fig. 2 is an explanatory illustration showing an example of the control of the absorption chiller-heater shown in Fig. 1, wherein (A) is an example of the control open-close controlling the valve interposed in the refrigerant pipe 20A 4 as an on-off valve, and (B) is an example of control controlling the opening by controlling the flow rate of the valve interposed in the refrigerant pipe 20A ; Fig. 3 is an explanatory illustration showing a prior art. [Explanation of signs] 1 High temperature regenerator 2 ' Gas burner 3 Low temperature regenerator 4 Condenser 4A Refrigerant tank 5 Hot drum 6 Evaporator 7 Absorber 8 Cold drum 4A 9 Low temperature heat exchanger 10 High temperature heat exchanger 12-16 Absorption solution pipe 17 Absorption pump 19 - 21 Refrigerant pipe 22 Refrigerant pump 23 Cotd/hot water pipe 23A Heat conductive pipe 24 Cooling water pipe C Control unit S1, S2 Temperature sensor V1 -V4 On-off valve DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT While the presently preferred embodiment of the present invention has been shown and described, it will be understood that the present invention is not limited thereto, and that various changes and modification may be made by those skilled in the art without departing from the scope of the invention as set forth in the appended claims. The embodiment of the present invention is described in detail based on Fig. 1 and Fig. 2. Moreover, for easier understanding, the same reference numerals are used in these figures for the part having the same function as that described in the Fig. 3. In the absorption chiller-heater of the present invention shown in Fig. 1 in which water is used as a refrigerant and lithium bromide (LiBr) solution is used as an absorption solution, wherein a refrigerant pipe 20A having an on-off valve V3 is provided between the bottom of a refrigerant tank 4A provided in a 5 condenser 4 and a refrigerant pipe 20 for leading a refrigerant liquid condensed in the condenser 4 to an evaporator 6, and the on-off valve V3 is opened or closed to be able to control the amount of the refrigerant liquid fed from the refrigerant tank 4A to the evaporator 6. Moreover, the reference numeral C indicates a control unit of the present invention provided with a microcomputer or the like, and the on-off valve V3 is opened or closed as necessary through a control program stored in a memory not shown of the control unit C as described later. In the absorption water cooler-heater with the aforementioned structure, a refrigerant vapor evaporated and separated from the diluted liquid and an intermediate absorption solution in which the density of the absorption solution becomes higher by separating the refrigerant vapor when the diluted absorption solution is heated and boiled in a high-temperature regenerator 1 by burning city gas with a gas burner 2 when flowing the cooling water in the cooling water pipe 24 by opening the on-off valve V1 to V4. A hot refrigerant vapor produced in the high temperature regenerator 1 enters a low temperature regenerator 3 passing through the upstream portion of a refrigerant pipe 19, heats the intermediate absorption solution produced by the high temperature regenerator 1 and delivered to the low temperature regenerator 3 passing through a high temperature heat exchanger 10 by an absorption solution pipe 15, radiates heat and condenses itself, and enters the condenser 4 through the downstream portion of the refrigerant pipe 19 provided with a refrigerant drain heat collector 11. Moreover, the refrigerant evaporated and separated from the intermediate absorption solution by heating in the low temperature regenerator 3 enters the condenser 4, condenses and liquefies through heat exchange with the cooling water flowing in the cooling water pipe 24, joins together the 6 refrigerant condensed and supplied from the refrigerant pipe 19, and passes through a refrigerant pipe 20 before entering the evaporator 6. The refrigerant liquid stored in a refrigerant accumulator of the evaporator 6 is spread by a refrigerant pump 22 interposed in the refrigerant pipe 21 over a heat conductive pipe 23A connected to a cold/hot water pipe 23 and evaporates through heat-exchange with water supplied through the cold/hot water pipe 23, and refrigerates the water flowing in the heat conductive pipe 23A. The refrigerant evaporated in the evaporator 6 enters an absorber 7, heated by the low temperature regenerator 3 to evaporate and separate the refrigerant, and absorbed by an absorption solution further increased in the absorption solution concentration, namely dense absorption solution, supplied through a low temperature heat exchanger 9 from an absorption solution pipe 16 and spread from above. Then, absorption solution reduced in the concentration by absorbing the refrigerant in the absorber 7, namely, the diluted absorption solution is returned to the high temperature regenerator 1 by operating an absorption solution pump 17. When the absorption chiller-heater is operated as mentioned above, cold water cooled by the heat of evaporation of the refrigerant in the heat conductive pipe 23A disposed in the interior of the evaporator 6 can be supplied by circulation to a not shown air-conditioning load through the cold/hot water pipe 23, allowing to perform a cooling operation such as space cooling. Moreover, in the absorption chiller-heater with the aforementioned structure, when the on-off valve V1, V2 is opened, and the diluted absorption solution is heated and boiled in the high temperature regenerator 1 with burning of city gas by the gas burner 2 without flowing the cooling water in the cooling water pipe 24, then, the refrigerant vapor evaporated and separated from the 7 diluted absorption solution and the absorption solution further increased in the absorption solution concentration by separating the refrigerant vapor are obtained, and they all enter the absorber 7 not the low temperature regenerator 3 due to the relationship of the passage resistance. Then, the refrigerant vapor having entered the absorber 7 enters the adjacent evaporator 6, radiates heat to the water flowing in the cold/hot water pipe 23A to be condensed, and heats the water flowing in the cold/hot water pipe 23. When the absorption chiller-heater is operated as mentioned above, the hot water heated mainly by the condensation heat of the refrigerant in the heat conductive pipe 23A disposed in the interior of the evaporator 6 can be supplied by circulation to a not shown air-conditioning load through the cold/hot water pipe 23, allowing to perform a heating operation such as space heating. Then, in the absorption chiller-heater of the present invention, when a cooling operation such as space cooling is conducted by circulating and supplying the cold water cooled in the heat conductive pipe 23A in the evaporator 6 to a load from the cold/hot water pipe 23, the structure is made in such a way that a control unit C closes the on-off valve V3, for example as shown in Fig. 2(A), when cooling inlet water temperature detected by a temperature sensor S1 installed on the inlet side of the absorber 7 of the cooling water pipe 24 becomes a given temperature, for example, not less than 25°C, and opens the valve when the cooling water inlet temperature detected by the temperature sensor S1 becomes other given temperature, for example, not more than 20°C (the set temperature can be changed with a microcomputer). Therefore, when the temperature of the cooling water supplied from the cooling water pipe 24 to the absorber 7 is low, the absorption effect of the refrigerant by the absorption solution in absorber 7 is easy to progress, and thus, 8 the amount of the refrigerant in the evaporator 6 tends to lack, the on-off valve V3 interposed in the refrigerant pipe 20A is opened to supply the refrigerant liquid in the refrigerant tank of the condenser 4 to the evaporator 6 through the refrigerant pipe 20A, 20 so that there is no possibility that the refrigerant lacks in the evaporator 6 and a cavitation occurs in the refrigerant pump 22 even in low density/low load operation. Moreover, it is possible to obtain the same effect as mentioned above with a structure wherein the on-off valve V3 interposed in the refrigerant pipe 20A is changed with a flow control valve whose opening control is freely done, and the opening is proportionally controlled by the control unit C with the cooling water inlet temperature detected by the temperature sensor S1 as a variable as shown in Fig. 2 (B) (the set temperature can be changed with a microcomputer). Moreover, the control unit C is constructed in such a way that, when the cooling operation such as space cooling is terminated by stopping the burning of city gas by the gas burner 2, the on-off valve V4 is opened after the burning of the gas burner 2 stopped to transfer the refrigerant liquid stored in the refrigerant accumulator of the evaporator 6 to the absorber 7 through a refrigerant pipe 21A by continuing the operation of the refrigerant pump 22 for a given time, for example, 10 minutes, and the absorption solution diluted by the refrigerant supplied from the evaporator 6 is circulated and supplied to the high temperature regenerator 1 and low temperature regenerator 3 to dilute the whole absorption solution. Moreover, the control unit C is constructed in such a way that, when the atmospheric temperature detected by a temperature sensor S2 is in a given temperature, for example, not more than 5°C, the on-off valve V3 interposed in the refrigerant pipe 20A is opened (it is possible to provide a structure wherein the opening time of the valve is controlled based on the atmospheric 9 temperature), and the refrigerant liquid stored in the refrigerant tank 4A in the condenser 4 is supplied to the absorber 7 through the evaporator 6 to further dilute the absorption solution. Therefore, the absorption solution dose not crystallize even in a cold district nor is diluted unnecessarily. Thus, according to the absorption chiller-heater in the present invention, it is possible to conduct a dilution operation in which the absorption solution will not be crystallized even in a cold district, and unnecessary dilution operation will not be conducted so that it is possible to instantly start the cooling operation such as space cooling by evaporate and separate in a short time a necessary amount of refrigerant required to start the cooling operation such as space cooling. Moreover, control unit C is constructed in such a way that, when the heating operation such as space heating by circulating and supplying the hot water heated by the heat conductive pipe 23A in the evaporator 6 from the cold/hot water pipe 23 to a load, the on-off valve V3 interposed in the refrigerant pipe 20A is opened so that the refrigerant liquid stored in the refrigerant tank 4A in the condenser 4 in cooling operation such as space cooling is returned to the absorber 7 through the evaporator 6 to be mixed (absorbed) in the absorption solution. Therefore, the density of the absorption solution circulating in the unit is reduced in total, and the temperature level of the cycle is reduced, thereby improving the durability of the absorption chiller-heater. It should be appreciated that the present invention is not limited to the aforementioned, but may be modified in various ways without departing from the scope of the invention as set forth in the appended claims. For example, the refrigerant pipe 20A provided with the on-off valve may be installed so as to lead directly to the evaporator 6 or the absorber 7. 10 Moreover, it is possible to construct the control unit C in such a way that, when the burning of the gas burner 2 is stopped for a given time, for example over 5 minutes, in a cooling operation in which the cold water is circulated and supplied from the cold/hot water pipe 23, an open valve signal for the on-off valve V3 will not be generated even if the temperature sensor S1 detects a temperature lower than a given 20°C. It is possible to avoid an unnecessary valve opening operation of the on-off valve V3 by constructing the control unit C in such a way. Besides, the fluid refrigerated or like in the evaporator 6 and supplied to an air-conditioning load may be the water or others to be supplied without phase change as in the aforementioned embodiment, or chlorofluorocarbon or the like to be supplied with phase change, so that a heat transport using latent heat would be enabled. As mentioned above, in the absorption chiller-heater according to the present invention, the refrigerant liquid evaporated in the evaporator will not be lacked even in low density/low load operation when the temperature of the cooling water is sufficiently low, thereby eliminating a fear that a cavitation occurs in the refrigerant pump. Moreover, in the absorption chiller-heater in which the control means has a function to open the flow control valve in heating operation, the density of the absorption solution circulating in the unit is reduced in the heating operation such as space heating and the temperature level in the cycle is lowered, thereby improving the durability of the absorption chiller-heater. Moreover, in the absorption chiller-heater in which the control means has a function to open the flow control valve based on the temperature of the atmospheric temperature in the cooling operation when the temperature of atmospheric temperature is lower than a given temperature, the absorption 11 solution is diluted so that the absorption solution will not be crystallized when the cooling operation is stopped, however, because unnecessary dilution is not performed, it is possible to evaporate and separate the refrigerant required for the cooling operation such as space cooling in a short time, thereby making it possible to instantly start the space cooling or the like. 12 WE CLAIM : 1. An absorption-chiller heater for circulating a refrigerant and an absorption solution by connecting an evaporator, an absorber, a regenerator, and a condenser, capable of selecting between a cooling operation for cooling a brine with evaporation heat of the refrigerant, and a heating operation for mainly heating the brine with the condensation heat of the refrigerant, said absorption chiller-heater comprising a refrigerant liquid storage part for storing the refrigerant liquid condensed by radiating heat into the cooling water in the condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe interposing a flow control valve for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser. 2. An absorption chiller-heater as claimed in claim 1 wherein said control means has a function to open the flow control valve during heating operation. 3. An absorption chiller-heater as claimed in claim 1 or 2 wherein said control means has a function to open the flow control valve based on the atmospheric temperature when the cooling operation is stopped during a lower atmospheric temperature than a given temperature. 13 4. An absorption chiller-heater, substantially as herein described, particularly with reference to Figs. 1 and 2 of the accompanying drawings. An absorption-chiller heater for circulating a refrigerant and an absorption solution by connecting an evaporator (6), an absorber (7), a regenerator (1, 3), and a condenser (4), capable of selecting between a cooling operation for cooling a brine with evaporation heat of the refrigerant, and a heating operation for mainly heating the brine with the condensation heat of the refrigerant, said absorption chiller-heater comprising a refrigerant liquid storage part (4A) for storing the refrigerant liquid condensed by radiating heat into the cooling water in the condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe (20A) interposing a flow control valve (V3) for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means (C) for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser.

Full Text

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to water cooler-heater.
2. Detailed Description of the Prior Art
As shown in Fig. 3, it is known that an absorption chiller-heater; is constructed to be selectable between a cooling operation such as space cooling conducted in such a way that a high temperature regenerator 1 having a gas burner 2, a low temperature regenerator 3, a condenser 4, an evaporator 6, an absorber 7, a low temperature heat exchanger 9, a high temperature heat exchanger 10, an absorption solution pump 17, and a refrigerant pump 22, etc. are connected with an absorption solution pipe and a refrigerant pipe; the refrigerant vapor that has been evaporated and separated from the absorption solution heated by the high temperature regenerator 1 and low temperature regenerator 3 is transferred to the condenser 4 and cooled by the cooling water flowing within the cooling water pipe 24 to be condensed, the condensed refrigerant liquid is transferred to the evaporator 6 to be evaporated, and the cold water cooled by the evaporation heat of the refrigerant is circulated to the cooling load via a cold/hot water pipe 23, and a heating operation such as space heating conducted in such a way that the refrigerant vapor which is evaporated and separated from the absorption solution heated by the high temperature regenerator 1 and the absorption solution separated therefrom by evaporating the refrigerant are directly transferred to a cold drum 8, and the hot
1

water heated mainly by the condensation heat of the refrigerant is circulated to a heating load via a cool/hot pipe 23. Such an absorption chiller is disclosed in US 6,370,893.
In the absorption chiller-heater with the aforementioned structure, a refrigerant tank 4A which stores the refrigerant liquid condensed by radiating heat into the cooling water flowing in the cooling water pipe 24 is provided inside the condenser 4 and the amount of the refrigerant liquid stored therein is determined by the magnitude of the load. Thus, when the cooling load is large, the difference in the density of the absorption solution is larger (i.e., the amount of refrigerant in the refrigerant accumulator increases), and, when the cooling load is low, the difference in the density of the refrigerant liquid is lower (i.e., the amount of refrigerant in the refrigerant accumulator decreases). Therefore, when the temperature of the cooling water is low and in low density/low load operation, sometimes the refrigerant liquid is insufficient in the evaporator 6 and a cavitation occurs in the refrigerant pump 22, resulting in damage.
Moreover, when the cooling operation such as space cooling is stopped, such an operation is conducted that the on-off valve V4 is manually opened to return the refrigerant liquid stored in the evaporator 6 to the absorber 7 to dilute the absorption solution or the refrigerant liquid in the refrigerant tank 4A is returned to the absorber 7 so that the absorption solution condensed through heating does not crystallize out.
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condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe interposing a flow control valve for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser.
In a preferred embodiment, the absorption chiller-heater is characterized in that the control means has a function to open the flow control valve when heating operation.
In a further embodiment, the absorption chiller-heater is characterized in that the control means has a function to open the flow control valve based on the atmospheric temperature when the cooling operation is stopped during a lower atmospheric temperature than the given temperature.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
These and other advantages of the present invention will become clear from following description with reference to the accompanying drawings, wherein :
Fig. 1 is an explanatory illustration showing an embodiment of the present invention ;
Fig. 2 is an explanatory illustration showing an example of the control of the absorption chiller-heater shown in Fig. 1, wherein (A) is an example of the control open-close controlling the valve interposed in the refrigerant pipe 20A
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as an on-off valve, and (B) is an example of control controlling the opening by controlling the flow rate of the valve interposed in the refrigerant pipe 20A ;
Fig. 3 is an explanatory illustration showing a prior art. [Explanation of signs]

1 High temperature regenerator
2 ' Gas burner
3 Low temperature regenerator
4 Condenser
4A Refrigerant tank
5 Hot drum
6 Evaporator
7 Absorber
8 Cold drum
4A

9 Low temperature heat exchanger
10 High temperature heat exchanger
12-16 Absorption solution pipe
17 Absorption pump 19 - 21 Refrigerant pipe
22 Refrigerant pump
23 Cotd/hot water pipe
23A Heat conductive pipe
24 Cooling water pipe
C Control unit
S1, S2 Temperature sensor V1 -V4 On-off valve
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While the presently preferred embodiment of the present invention has been shown and described, it will be understood that the present invention is not limited thereto, and that various changes and modification may be made by those skilled in the art without departing from the scope of the invention as set forth in the appended claims.
The embodiment of the present invention is described in detail based on Fig. 1 and Fig. 2. Moreover, for easier understanding, the same reference numerals are used in these figures for the part having the same function as that described in the Fig. 3.
In the absorption chiller-heater of the present invention shown in Fig. 1 in which water is used as a refrigerant and lithium bromide (LiBr) solution is used as an absorption solution, wherein a refrigerant pipe 20A having an on-off valve V3 is provided between the bottom of a refrigerant tank 4A provided in a
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condenser 4 and a refrigerant pipe 20 for leading a refrigerant liquid condensed in the condenser 4 to an evaporator 6, and the on-off valve V3 is opened or closed to be able to control the amount of the refrigerant liquid fed from the refrigerant tank 4A to the evaporator 6.
Moreover, the reference numeral C indicates a control unit of the present invention provided with a microcomputer or the like, and the on-off valve V3 is opened or closed as necessary through a control program stored in a memory not shown of the control unit C as described later.
In the absorption water cooler-heater with the aforementioned structure, a refrigerant vapor evaporated and separated from the diluted liquid and an intermediate absorption solution in which the density of the absorption solution becomes higher by separating the refrigerant vapor when the diluted absorption solution is heated and boiled in a high-temperature regenerator 1 by burning city gas with a gas burner 2 when flowing the cooling water in the cooling water pipe 24 by opening the on-off valve V1 to V4.
A hot refrigerant vapor produced in the high temperature regenerator 1 enters a low temperature regenerator 3 passing through the upstream portion of a refrigerant pipe 19, heats the intermediate absorption solution produced by the high temperature regenerator 1 and delivered to the low temperature regenerator 3 passing through a high temperature heat exchanger 10 by an absorption solution pipe 15, radiates heat and condenses itself, and enters the condenser 4 through the downstream portion of the refrigerant pipe 19 provided with a refrigerant drain heat collector 11.
Moreover, the refrigerant evaporated and separated from the intermediate absorption solution by heating in the low temperature regenerator 3 enters the condenser 4, condenses and liquefies through heat exchange with the cooling water flowing in the cooling water pipe 24, joins together the
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refrigerant condensed and supplied from the refrigerant pipe 19, and passes through a refrigerant pipe 20 before entering the evaporator 6.
The refrigerant liquid stored in a refrigerant accumulator of the evaporator 6 is spread by a refrigerant pump 22 interposed in the refrigerant pipe 21 over a heat conductive pipe 23A connected to a cold/hot water pipe 23 and evaporates through heat-exchange with water supplied through the cold/hot water pipe 23, and refrigerates the water flowing in the heat conductive pipe 23A.
The refrigerant evaporated in the evaporator 6 enters an absorber 7, heated by the low temperature regenerator 3 to evaporate and separate the refrigerant, and absorbed by an absorption solution further increased in the absorption solution concentration, namely dense absorption solution, supplied through a low temperature heat exchanger 9 from an absorption solution pipe 16 and spread from above.
Then, absorption solution reduced in the concentration by absorbing the refrigerant in the absorber 7, namely, the diluted absorption solution is returned to the high temperature regenerator 1 by operating an absorption solution pump 17.
When the absorption chiller-heater is operated as mentioned above, cold water cooled by the heat of evaporation of the refrigerant in the heat conductive pipe 23A disposed in the interior of the evaporator 6 can be supplied by circulation to a not shown air-conditioning load through the cold/hot water pipe 23, allowing to perform a cooling operation such as space cooling.
Moreover, in the absorption chiller-heater with the aforementioned structure, when the on-off valve V1, V2 is opened, and the diluted absorption solution is heated and boiled in the high temperature regenerator 1 with burning of city gas by the gas burner 2 without flowing the cooling water in the cooling water pipe 24, then, the refrigerant vapor evaporated and separated from the
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diluted absorption solution and the absorption solution further increased in the absorption solution concentration by separating the refrigerant vapor are obtained, and they all enter the absorber 7 not the low temperature regenerator 3 due to the relationship of the passage resistance.
Then, the refrigerant vapor having entered the absorber 7 enters the adjacent evaporator 6, radiates heat to the water flowing in the cold/hot water pipe 23A to be condensed, and heats the water flowing in the cold/hot water pipe 23.
When the absorption chiller-heater is operated as mentioned above, the hot water heated mainly by the condensation heat of the refrigerant in the heat conductive pipe 23A disposed in the interior of the evaporator 6 can be supplied by circulation to a not shown air-conditioning load through the cold/hot water pipe 23, allowing to perform a heating operation such as space heating.
Then, in the absorption chiller-heater of the present invention, when a cooling operation such as space cooling is conducted by circulating and supplying the cold water cooled in the heat conductive pipe 23A in the evaporator 6 to a load from the cold/hot water pipe 23, the structure is made in such a way that a control unit C closes the on-off valve V3, for example as shown in Fig. 2(A), when cooling inlet water temperature detected by a temperature sensor S1 installed on the inlet side of the absorber 7 of the cooling water pipe 24 becomes a given temperature, for example, not less than 25°C, and opens the valve when the cooling water inlet temperature detected by the temperature sensor S1 becomes other given temperature, for example, not more than 20°C (the set temperature can be changed with a microcomputer).
Therefore, when the temperature of the cooling water supplied from the cooling water pipe 24 to the absorber 7 is low, the absorption effect of the refrigerant by the absorption solution in absorber 7 is easy to progress, and thus,
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the amount of the refrigerant in the evaporator 6 tends to lack, the on-off valve V3 interposed in the refrigerant pipe 20A is opened to supply the refrigerant liquid in the refrigerant tank of the condenser 4 to the evaporator 6 through the refrigerant pipe 20A, 20 so that there is no possibility that the refrigerant lacks in the evaporator 6 and a cavitation occurs in the refrigerant pump 22 even in low density/low load operation.
Moreover, it is possible to obtain the same effect as mentioned above with a structure wherein the on-off valve V3 interposed in the refrigerant pipe 20A is changed with a flow control valve whose opening control is freely done, and the opening is proportionally controlled by the control unit C with the cooling water inlet temperature detected by the temperature sensor S1 as a variable as shown in Fig. 2 (B) (the set temperature can be changed with a microcomputer).
Moreover, the control unit C is constructed in such a way that, when the cooling operation such as space cooling is terminated by stopping the burning of city gas by the gas burner 2, the on-off valve V4 is opened after the burning of the gas burner 2 stopped to transfer the refrigerant liquid stored in the refrigerant accumulator of the evaporator 6 to the absorber 7 through a refrigerant pipe 21A by continuing the operation of the refrigerant pump 22 for a given time, for example, 10 minutes, and the absorption solution diluted by the refrigerant supplied from the evaporator 6 is circulated and supplied to the high temperature regenerator 1 and low temperature regenerator 3 to dilute the whole absorption solution.
Moreover, the control unit C is constructed in such a way that, when the atmospheric temperature detected by a temperature sensor S2 is in a given temperature, for example, not more than 5°C, the on-off valve V3 interposed in the refrigerant pipe 20A is opened (it is possible to provide a structure wherein the opening time of the valve is controlled based on the atmospheric
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temperature), and the refrigerant liquid stored in the refrigerant tank 4A in the condenser 4 is supplied to the absorber 7 through the evaporator 6 to further dilute the absorption solution. Therefore, the absorption solution dose not crystallize even in a cold district nor is diluted unnecessarily.
Thus, according to the absorption chiller-heater in the present invention, it is possible to conduct a dilution operation in which the absorption solution will not be crystallized even in a cold district, and unnecessary dilution operation will not be conducted so that it is possible to instantly start the cooling operation such as space cooling by evaporate and separate in a short time a necessary amount of refrigerant required to start the cooling operation such as space cooling.
Moreover, control unit C is constructed in such a way that, when the heating operation such as space heating by circulating and supplying the hot water heated by the heat conductive pipe 23A in the evaporator 6 from the cold/hot water pipe 23 to a load, the on-off valve V3 interposed in the refrigerant pipe 20A is opened so that the refrigerant liquid stored in the refrigerant tank 4A in the condenser 4 in cooling operation such as space cooling is returned to the absorber 7 through the evaporator 6 to be mixed (absorbed) in the absorption solution.
Therefore, the density of the absorption solution circulating in the unit is reduced in total, and the temperature level of the cycle is reduced, thereby improving the durability of the absorption chiller-heater.
It should be appreciated that the present invention is not limited to the aforementioned, but may be modified in various ways without departing from the scope of the invention as set forth in the appended claims.
For example, the refrigerant pipe 20A provided with the on-off valve may be installed so as to lead directly to the evaporator 6 or the absorber 7.
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Moreover, it is possible to construct the control unit C in such a way that, when the burning of the gas burner 2 is stopped for a given time, for example over 5 minutes, in a cooling operation in which the cold water is circulated and supplied from the cold/hot water pipe 23, an open valve signal for the on-off valve V3 will not be generated even if the temperature sensor S1 detects a temperature lower than a given 20°C. It is possible to avoid an unnecessary valve opening operation of the on-off valve V3 by constructing the control unit C in such a way.
Besides, the fluid refrigerated or like in the evaporator 6 and supplied to an air-conditioning load may be the water or others to be supplied without phase change as in the aforementioned embodiment, or chlorofluorocarbon or the like to be supplied with phase change, so that a heat transport using latent heat would be enabled.
As mentioned above, in the absorption chiller-heater according to the present invention, the refrigerant liquid evaporated in the evaporator will not be lacked even in low density/low load operation when the temperature of the cooling water is sufficiently low, thereby eliminating a fear that a cavitation occurs in the refrigerant pump.
Moreover, in the absorption chiller-heater in which the control means has a function to open the flow control valve in heating operation, the density of the absorption solution circulating in the unit is reduced in the heating operation such as space heating and the temperature level in the cycle is lowered, thereby improving the durability of the absorption chiller-heater.
Moreover, in the absorption chiller-heater in which the control means has a function to open the flow control valve based on the temperature of the atmospheric temperature in the cooling operation when the temperature of atmospheric temperature is lower than a given temperature, the absorption
11

solution is diluted so that the absorption solution will not be crystallized when the cooling operation is stopped, however, because unnecessary dilution is not performed, it is possible to evaporate and separate the refrigerant required for the cooling operation such as space cooling in a short time, thereby making it possible to instantly start the space cooling or the like.
12

WE CLAIM :
1. An absorption-chiller heater for circulating a refrigerant and an absorption
solution by connecting an evaporator, an absorber, a regenerator, and a
condenser, capable of selecting between a cooling operation for cooling a brine
with evaporation heat of the refrigerant, and a heating operation for mainly
heating the brine with the condensation heat of the refrigerant, said absorption
chiller-heater comprising a refrigerant liquid storage part for storing the
refrigerant liquid condensed by radiating heat into the cooling water in the
condenser during the cooling operation, wherein the absorption chiller-heater is
provided with a refrigerant pipe interposing a flow control valve for connecting
said refrigerant liquid storage part to the evaporator or the absorber, and a
control means for controlling said flow control valve based on the temperature of
the cooling water flowing into the condenser.
2. An absorption chiller-heater as claimed in claim 1 wherein said control
means has a function to open the flow control valve during heating operation.
3. An absorption chiller-heater as claimed in claim 1 or 2 wherein said
control means has a function to open the flow control valve based on the
atmospheric temperature when the cooling operation is stopped during a lower
atmospheric temperature than a given temperature.
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4. An absorption chiller-heater, substantially as herein described,
particularly with reference to Figs. 1 and 2 of the accompanying drawings.
An absorption-chiller heater for circulating a refrigerant and an absorption solution by connecting an evaporator (6), an absorber (7), a regenerator (1, 3), and a condenser (4), capable of selecting between a cooling operation for cooling a brine with evaporation heat of the refrigerant, and a heating operation for mainly heating the brine with the condensation heat of the refrigerant, said absorption chiller-heater comprising a refrigerant liquid storage part (4A) for storing the refrigerant liquid condensed by radiating heat into the cooling water in the condenser during the cooling operation, wherein the absorption chiller-heater is provided with a refrigerant pipe (20A) interposing a flow control valve (V3) for connecting said refrigerant liquid storage part to the evaporator or the absorber, and a control means (C) for controlling said flow control valve based on the temperature of the cooling water flowing into the condenser.

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Patent Number

201685

Indian Patent Application Number

00173/KOL/2003

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

23-Feb-2007

Date of Filing

20-Mar-2003

Name of Patentee

SANYO ELECTRIC CO.LTD.,

Applicant Address

5-5 KEIHANHONDORI 2-CHOME ,MORIGUCHI ,OSAKA-FU

Inventors:

#	Inventor's Name	Inventor's Address
1	YAMAZAKI SHIGUMA	1 OTSUKI-CHO,ASHIKAGA-SHI,TOCHIGI-KEN,
2	ENOMOTO EIICHI	1 OTSUKI-CHO,ASHIKAGA-SHI,TOCHIGI-KEN,
3	FURUKAWA MASAHIRO	1 OTSUKI-CHO,ASHIKAGA-SHI,TOCHIGI-KEN,
4	FUNAI HIDEKI	1 OTSUKI-CHO,ASHIKAGA-SHI,TOCHIGI-KEN,

PCT International Classification Number

F 25B 15/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2002-150752	2002-05-24	Japan