JP4953433B2 - Absorption heat pump system - Google Patents

Description

  The present invention relates to an absorption heat pump system including an absorption heat pump circuit having an evaporator for evaporating a refrigerant.

  The absorption heat pump system includes an absorption heat pump circuit in which an evaporator, an absorber, a regenerator, and a condenser are connected in order. That is, the evaporator evaporates the refrigerant, the absorber absorbs the refrigerant vapor in the absorption liquid, the regenerator separates the refrigerant vapor from the absorption liquid and supplies it to the condenser, and the absorption liquid after separating the refrigerant vapor is supplied. Returning to the absorber, the condenser is configured to operate in a form that performs an absorption heat pump cycle in which refrigerant vapor is condensed and returned to the evaporator. In the heat pump cycle, the cold generated in the evaporator is used for cooling in the form of cooling the cold water, and the warm heat generated in the condenser and the absorber is used for hot water supply and heating in the form of warming the hot water. Used for such purposes.

In such an absorption heat pump system, cold water that has absorbed heat from the normal atmosphere or room air is circulated through a heat transfer pipe disposed in the evaporator, thereby evaporating the refrigerant in the evaporator by absorbing heat from the cold water ( For example, see Patent Document 1.)
Further, the absorption heat pump system described above includes a heat source device such as an engine, and exhaust heat from the heat source device heats the regenerator, and low-temperature exhaust heat after heating the regenerator returns to the atmosphere. What is released is known.

JP-A-5-280821

In the absorption heat pump system of Patent Document 1 described above, the temperature of the hot water, which is the output temperature of the absorption heat pump circuit, generally needs to be about 45 ° C. Therefore, the absorber and the condenser that heat the hot water are condensed. The temperature of the cooling water circulating through the vessel needs to be maintained at about 48 ° C. Assuming that the exhaust heat of the heat source unit that heats the regenerator is about 88 ° C., the temperature of the refrigerant in the evaporator needs to be about 20 ° C. However, when the heat source of the refrigerant of the evaporator is the heat of cold water absorbed from the atmosphere or room air, it may be difficult to heat the refrigerant of the evaporator to about 20 ° C.
For this reason, the design conditions of the absorption heat pump system have become strict, and it has been difficult to realize an absorption heat pump system with a high coefficient of performance.

  On the other hand, in the absorption heat pump system provided with a heat source device, low-temperature exhaust heat that cannot be effectively used after heating the regenerator among the exhaust heat of the heat source device is directly released to the atmosphere. For this reason, effective heat utilization cannot be achieved and there is room for improvement, and the low-temperature exhaust heat described above is released to the atmosphere, which is one factor that causes a heat island phenomenon in which the temperature rises.

  The present invention has been made in view of the above problems, and its purpose is to always maintain an output temperature above a certain level in winter and the like, and to improve the coefficient of performance. The present invention provides an absorption heat pump that can suppress the heat island phenomenon.

In order to achieve the above object, a first feature of an absorption heat pump system having an absorption heat pump circuit including an evaporator for evaporating a refrigerant according to the present invention is embedded in the ground, and the refrigerant is An embedded heat exchanger for exchanging heat between, and configured to be operable in a refrigerant circulation state in which the refrigerant of the evaporator of the absorption heat pump circuit is circulated with the embedded heat exchanger ,
A heat source for supplying heat to the regenerator of the absorption heat pump circuit;
An exhaust heat recovery heat exchanger that recovers exhaust heat of the heat source device by heat exchange with the refrigerant;
In the refrigerant circulation state, the refrigerant of the evaporator is circulated in a state where the buried heat exchanger and the exhaust heat recovery heat exchanger are circulated in order .

According to the first characteristic configuration described above, since the heat source of the refrigerant of the absorber is the ground at a substantially constant temperature of about 20 ° C. throughout the year, the refrigerant temperature of the condenser can be a constant temperature of about 20 ° C., The output temperature of the absorption heat pump system described above can be about 45 ° C. As a result, the design condition of the absorption heat pump system can be afforded.

In addition, by using the underground at about 20 ° C. as a heat source, compared to the case where the heat of the cooling water absorbed from the atmosphere or indoor air that may be lower than 20 ° C. in the winter season or the like is used as the heat source, Since the refrigerant temperature of the condenser can be increased, the coefficient of performance of the absorption heat pump system can be improved.
Furthermore, the heat exchange efficiency can be improved and the coefficient of performance of the absorption heat pump system can be further improved by directly exchanging heat between the refrigerant of the evaporator and the ground without passing through another heat medium.
Furthermore, after the refrigerant of the evaporator absorbs the underground heat in the buried heat exchanger, the exhaust heat of the heat source apparatus is further absorbed in the exhaust heat recovery heat exchanger, thereby further increasing the temperature of the refrigerant of the evaporator. be able to.
Moreover, even low-temperature exhaust heat from the heat source device can be effectively used without being wasted to the atmosphere.

In addition to the first feature configuration, the second feature configuration of the absorption heat pump system according to the present invention is that the refrigerant is water, and cooling water that cools at least one of the absorber and the condenser of the absorption heat pump circuit. The exhaust heat recovery heat exchanger and the refrigerant side of the embedded heat exchanger are circulated in a state where they are circulated in order, and the refrigerant circulation state and the cooling water circulation state are It is in the point provided with the switching means to switch.

According to the second characteristic configuration, even when the absorption heat pump is operated in the cooling mode, such as in summer, and the heat demand is small and heat cannot be used effectively, the cooling is performed from the refrigerant circulation state described above. By switching to the water circulation state, the buried heat exchanger releases the heat generated by the absorber and condenser of the absorption heat pump circuit and the exhaust heat of the heat source unit into the ground, and therefore releases heat to the atmosphere. Compared with, the temperature rise of the atmosphere can be reduced. Therefore, even when the absorption heat pump system is installed in a place where the ground surface such as an urban area is covered with asphalt or the like, the heat island phenomenon can be suppressed.

The third feature configuration of the absorption heat pump system according to the present invention is the above-described first feature configuration or second feature configuration, wherein the heat source device is an engine, and the regenerator is used to cool the engine cooling water after cooling the engine. An engine coolant heating heat exchanger that heats the engine coolant supplied to the regenerator by heat exchange with exhaust gas exhaust heat discharged from the engine. The exhaust heat recovery heat exchanger disposed in the exhaust path of the engine uses the exhaust gas exhaust heat exhausted from the engine as the refrigerant, and the exhaust gas exhaust heat after passing through the engine cooling water heating heat exchanger as the refrigerant. It is in the point arrange | positioned rather than the said engine-cooling-water heating heat exchanger of the said exhaust path so that it may collect | recover by heat exchange.

According to the third characteristic configuration, in the refrigerant circulation state, the exhaust heat recovery heat exchanger recovers the low-temperature exhaust heat after heating the regenerator of the absorption heat pump circuit from the exhaust heat of the engine, and evaporates it. It can be effectively used for heating the refrigerant of the vessel. Further, in the circulating state of the cooling water, the low-temperature exhaust heat described above can be released into the ground by the embedded heat exchanger, and the release of useless exhaust heat to the atmosphere can be suppressed, thereby reducing the temperature rise in the atmosphere.

  An embodiment of an absorption heat pump system 100 of the present invention will be described based on the drawings.

FIG. 1 is a schematic configuration diagram of an absorption heat pump system 100 that can be operated in a state called a refrigerant circulation state, which will be described later, mainly in winter. FIG. 2 is a state called a cooling water circulation state, which will be described later, mainly in summer. It is a schematic block diagram of the absorption heat pump system 100 which can be drive | operated by. In the refrigerant circulation state and the coolant circulation state, the refrigerant A circulates through the evaporator 1, the absorber 2, the regenerator 3, and the condenser 4 while causing a phase change. Circulate while changing the concentration between the two. In this embodiment, water is used as the refrigerant, and an LiBr aqueous solution is used as the absorbing liquid. That is, it is a water-LiBr absorption heat pump system 100.
1 and 2, the circulation system unique to the present invention for heating the refrigerant A in the evaporator 1 is shown by a thick solid line, and cooling water for cooling at least one of the absorber 2 and the condenser 4 is shown. The CW circulation system is indicated by a thick broken line. In addition, the three-way valves 41 to 48 are indicated by triangular marks in which the open state is filled, and in the closed state by white triangular marks, and the arrows indicate the flow direction of the fluid flowing in the road.

  First, based on FIG. 1, the structure of the absorption heat pump system 100 according to the present application will be described.

  An absorption heat pump circuit X having an evaporator 1 for evaporating the refrigerant A is provided, and the refrigerant A of the evaporator 1 included in the absorption heat pump circuit X is used as an embedded heat exchanger 34 provided in the ground with the evaporator 1. It is comprised so that it can drive | operate in the refrigerant | coolant circulation state circulated between.

  The absorption heat pump circuit X includes an absorption heat pump circuit X in which an evaporator 1, an absorber 2, a regenerator 3, and a condenser 4 are connected in order. The evaporator 1 and the absorber 2 are connected by a refrigerant vapor flow pipe 12, the regenerator 3 and the condenser 4 are connected by a refrigerant vapor flow pipe 9, and the condenser 4 and the evaporator 1 have an expansion valve 11. The refrigerant circulation pipe 10 is connected.

  Then, the working fluid circulation path 5 circulates the absorbing liquid D whose concentration changes between the absorber 2 and the regenerator 3, and the circulation pump 7 is connected to the working fluid circulation path 5 a in the working fluid circulation path. The return path 5b is provided with an expansion valve 8 and a refrigerant heat exchanger 6 for exchanging heat between the fluid flowing in the forward path 5a of the working fluid circulation path and the return path 5b of the working fluid circulation path.

  That is, the evaporator 1 evaporates the refrigerant A2, and the evaporated refrigerant vapor A2 is supplied to the absorber 2 through the refrigerant vapor circulation pipe 12. The absorber 2 absorbs the refrigerant vapor A2 in the absorption liquid D, and the low-concentration absorption liquid D is pumped by the circulation pump 7 to the regenerator 3 through the working fluid circulation path 5a. The regenerator 3 separates the refrigerant vapor A2 from the low-concentration absorbent D and supplies it to the condenser 4 via the refrigerant vapor circulation path 9, and also separates the high-concentration absorbent D and returns to the working fluid circulation path. The pressure is reduced by the expansion valve 8 through the passage 5 b and supplied to the absorber 2. The condenser 4 condenses the refrigerant vapor A <b> 2, and the refrigerant A is decompressed by the expansion valve 11 through the refrigerant flow pipe 10 and returns to the evaporator 1. The low-concentration absorbing liquid D that circulates in the outgoing path 5a of the working fluid circulation path recovers the heat of the high-temperature high-concentration absorbing liquid D that circulates in the return path 5b of the working fluid circulation path in the refrigerant heat exchanger 6; Absorption heat pump cycle is established.

  Then, the cooling water circulation path 30 recovers the heat generated by the cooling water CW pumped by the circulation pump 33 in the absorber 2 and the condenser 4, and then flows to the heat operation heat exchanger 62 to pass through the heat transfer pipe 62a. It arrange | positions so that heat may be supplied to the water H for circulating heat, and the heat supplied to the water H for heat is utilized for heating or hot water supply.

The cold heat supply circuit 35 is arranged so that the refrigerant A of the evaporator 1 pumped by the circulation pump 32 flows through the cold heat operation heat exchanger 61 and supplies cold water to the cold water C flowing through the heat transfer pipe 61a. The cold heat supplied to the cold water C is used for cooling and the like.
However, in the refrigerant circulation state of FIG. 1, this cold supply circuit 35 is not used, and in the cooling water circulation state of FIG. 2 described later, the cold supply circuit 35 is used.

  The engine 21 (an example of a heat source device) is driven by a fuel G such as natural gas and supplies a part of the shaft output as a power source of the generator 24. The electric power generated by the generator 24 is used to operate the auxiliary equipment of the absorption heat pump system 100 and other electric power loads.

  The engine 21 includes an exhaust gas passage 22 (an example of an exhaust passage) through which the exhaust gas E flows, and an engine cooling water circulation passage 23 through which the engine cooling water JW flows. The engine cooling water circulation path 23 includes an engine cooling water JW pumped by a circulation pump 25, an engine cooling water heating heat exchanger 26 that is provided in the exhaust gas path 22 and collects exhaust gas exhaust heat, and an absorption type. It arrange | positions so that it may distribute | circulate through the regenerator 3 of the heat pump circuit X in order. The engine coolant JW recovers the heat of the engine 21 in the engine 21, recovers exhaust gas exhaust heat in the engine coolant heating heat exchanger 26, and supplies the recovered heat to the regenerator 3.

  The above is the basic configuration of the absorption heat pump system 100. Hereinafter, the exhaust heat recovery heat exchange for recovering the exhaust heat of the evaporator 1, the embedded heat exchanger 34, and the engine 21 of the refrigerant A of the evaporator 1 will be described below. The refrigerant circulation state in which the refrigerant 27 and the condenser 4 are circulated in the order with the condenser 27, and the cooling water CW for cooling the absorber 2 or the condenser 4 in the order of the exhaust heat recovery heat exchanger 27 and the embedded heat exchanger 34, respectively. The cooling means circulating state that circulates in the circulating state and the switching means Y that switches between the refrigerant circulating state and the cooling water circulating state will be described in further detail.

(Refrigerant circulation state)
As shown by a thick solid line in FIG. 1, the heat absorbing / dissipating circuit 31 includes an embedded heat exchanger 34 in which the refrigerant A of the evaporator 1 can exchange heat with the ground, and the exhaust gas path 22 to heat the engine coolant. The heat exchanger 26 is arranged so as to circulate in the order of the exhaust heat recovery heat exchanger 27 that recovers the low temperature exhaust gas exhaust heat after recovering the exhaust gas exhaust heat.
The refrigerant circulation state is a state in which the refrigerant A sent out from the evaporator 1 by the circulation pump 32 is circulated through the evaporator 1 and the heat absorption / radiation circulation path 31.

  The controller 50 opens and closes the three-way valves 41, 42, 43, 44, 45, 47 provided in the heat absorption / radiation circulation path 31, changes the refrigerant circulation state, and cools the refrigerant A through the cold supply circulation path 35. It is configured to be switchable to a state where it flows to the operation heat exchanger 61.

  In the refrigerant circulation state, the refrigerant A of the evaporator 1 is pumped by the circulation pump 32 to the heat absorption / radiation circulation path 31, flows through the embedded heat exchanger 34 through the three-way valves 43, 41, and is discharged through the three-way valve 45. It circulates through the heat recovery heat exchanger 27 and returns to the evaporator 1 through the three-way valves 42 and 44.

[Cooling water circulation state]
In the cooling water circulation state, as shown by a thick broken line in FIG. 2, the cooling water CW is connected to the above-described cooling water circulation path 30, and the outlet side of the condenser 4 in the cooling water circulation path 30 and the heat absorption / radiation circulation path 31. It is the state which circulates through each in order of the path 51, the absorption-and-radiation circulation path 31, and the connection path 52 which connects the inlet side of the absorber 2 in the cooling water circulation path 30 and the absorption-and-radiation circulation path 31.

  The control device 50 switches the open / close state of the three-way valves 46, 48 provided in the cooling water circulation path 30 and the three-way valves 41, 42, 45, 47 provided in the heat absorption / dissipation circulation path 31 to change the refrigerant circulation state and cooling. It is comprised so that it may function as the switching means Y in the form which switches a water circulation state.

  In the cooling water circulation state, the cooling water CW is pumped by the circulation pump 33, circulates through the cooling water circulation path 30, circulates through the connection path 51 via the three-way valve 46, and passes through the three-way valve 47. The exhaust heat recovery heat exchanger 27 is circulated, the embedded heat exchanger 34 is circulated through the three-way valve 42 and the three-way valve 41, the connection path 52 is circulated through the three-way valve 45, and the three-way valve 48 is circulated. And circulate back to the cooling water circulation path 30. In the cooling water circulation state, the cooling water CW always flows through the heat transfer pipe 62a of the thermal operation heat exchanger 62 to heat the hot water H, and the heated hot water H is used for hot water supply or the like.

  Next, specific examples of the refrigerant circulation operation in the refrigerant circulation state and the cooling water circulation operation in the cooling water circulation state will be described.

[Refrigerant circulation operation]
The refrigerant circulation operation is an operation for operating the absorption heat pump system 100 in a refrigerant circulation state as shown in FIG. 1, and is performed in order to operate the absorption heat pump system 100 satisfactorily in winter and the like. The refrigerant A is executed in a form that is heated by ground heat and low-temperature exhaust heat of the exhaust heat of the engine 21. The switching means Y controls the open / closed state of the three-way valves 43, 44 so that the refrigerant A of the evaporator 1 is circulated through the heat absorption / dissipation circuit 31. And the remaining refrigerant | coolant A which became low temperature because a part of refrigerant | coolant A evaporated in the inside of the evaporator 1 is pumped by the circulation pump 32, distribute | circulates to the heat absorption / radiation circulation path 31 via the three-way valve 43, The buried heat exchanger 34 absorbs underground heat of about 20 ° C., and the exhaust heat recovery heat exchanger 27 further absorbs low-temperature exhaust heat of the relatively high temperature engine 21 of 20 ° C. or more via the three-way valve 44. Then, the refrigerant circulation operation is executed by returning to the evaporator 1 and repeating the circulation of heating the refrigerant A of the evaporator 1. Thereby, the temperature of the refrigerant | coolant of the evaporator 1 can be made into 20 degreeC or more, for example, when the temperature of the engine cooling water JW which circulates through the engine cooling water circulation path 23 is about 88 degreeC, it is thermal operation heat exchange. The output temperature that is the temperature of the cooling water CW before heat exchange in the vessel 62 can be maintained at about 45 ° C.

  At this time, the switching means Y controls the open / closed state of the three-way valves 45, 46, 48, so that the cooling water CW is in a state of flowing through the cooling water circulation path 30.

[Cooling water circulation operation]
The cooling water circulation operation is an operation state in which the absorption heat pump system 100 is operated in a cooling water circulation state as shown in FIG. 2, and is executed when exhaust heat from the absorption heat pump system 100 cannot be used effectively in summer or the like. The cooling water CW is executed in such a manner that the warm heat of the absorber 2 and the condenser 4 and the low-temperature exhaust gas exhaust heat of the engine 21 are recovered and released into the ground. The switching means Y controls the open / closed state of the three-way valves 41, 42, 45, 46, 47, 48 so that the cooling water CW flows through the heat absorption / radiation circulation path 31. Then, the cooling water CW is pumped by the circulation pump 33, collects the heat of the absorber 2 and the condenser 4 in the cooling water circulation path 30, flows through the connection path 51 via the three-way valve 46, and passes through the three-way valve 47. Then, the low-temperature exhaust heat is recovered by the exhaust heat recovery heat exchanger 27, and the absorber 2 and the condenser 4 are connected in the embedded heat exchanger 34 via the three-way valves 42 and 41. The cooling water circulation operation can be performed by repeating the circulation in which the exhaust heat of the heat and the low temperature exhaust gas is discharged into the ground, is circulated through the connection path 52 via the three-way valve 45, and returns to the cooling water circulation path 30 via the three-way valve 48. Executed.

  At this time, the switching means Y controls the open / closed state of the three-way valves 43, 44, whereby the refrigerant A of the evaporator 1 flows through the cold supply circuit 35 and flows through the heat transfer pipe 61 a of the cold operation heat exchanger 61. Thus, the cold water C is cooled.

  As described above, the switching unit Y appropriately switches between the refrigerant circulation state and the cooling water circulation state, thereby enabling the single absorption heat pump system 100 to execute the refrigerant circulation operation and the cooling water circulation operation.

  In the summer, it is considered that the exhaust heat released into the ground by the buried heat exchanger 34 can be collected in the winter about half a year later. It is considered that the coefficient of performance of the heat pump system 100 can be improved throughout the year by using the heat source of the heat pump system 100.

[Another embodiment]
(1) In the above embodiment, the cooling water circulation path 30 has been shown to be disposed inside both the absorber 2 and the condenser 4, but only one of them is passed through. Also good.

(2) In the refrigerant circulation state of the above embodiment, the heat absorption / radiation circuit 31 may be arranged so that the refrigerant A of the evaporator 1 does not flow through the exhaust heat recovery heat exchanger 27.

  The absorption heat pump system of the present invention can be used effectively as an absorption heat pump that can always maintain an output temperature above a certain level in winter and the like, and can suppress the heat island phenomenon in summer. is there.

Schematic configuration diagram of the absorption heat pump system of the present invention in winter Schematic configuration diagram of the absorption heat pump system of the present invention in summer

Explanation of symbols

1: Evaporator 31: Absorption / radiation circuit 34: Embedded heat exchanger 50: Control device (an example of switching means)
100: Absorption-type heat pump system X: Absorption-type heat pump circuit A: Refrigerant E: Exhaust gas C: Cooling water H: Hot water G: Fuel CW: Cooling water JW: Engine cooling water

Claims (3)

An absorption heat pump system comprising an absorption heat pump circuit having an evaporator for evaporating refrigerant,
Embedded in the ground, comprising a buried heat exchanger for exchanging heat between the refrigerant and the ground,
The refrigerant in the evaporator of the absorption heat pump circuit is configured to be operated in a refrigerant circulating state is circulated between said buried heat exchanger,
A heat source for supplying heat to the regenerator of the absorption heat pump circuit;
An exhaust heat recovery heat exchanger that recovers exhaust heat of the heat source device by heat exchange with the refrigerant;
An absorption heat pump system that circulates the refrigerant in the evaporator in a state in which the embedded heat exchanger and the exhaust heat recovery heat exchanger are circulated in order in the refrigerant circulation state . The refrigerant is water;
Cooling in which cooling water that has cooled at least one of the absorber and the condenser of the absorption heat pump circuit is circulated in a state where the exhaust heat recovery heat exchanger and the refrigerant side of the embedded heat exchanger are circulated in this order. It is configured to be operable in a water circulation state,
The absorption heat pump system according to claim 1 , further comprising switching means for switching between the refrigerant circulation state and the cooling water circulation state . The heat source machine is an engine;
Circulating engine cooling water after cooling the engine as a heat source of the regenerator with the regenerator,
An engine cooling water heating heat exchanger for heating the engine cooling water supplied to the regenerator by heat exchange with exhaust gas exhaust heat discharged from the engine is disposed in the exhaust path of the engine,
The exhaust heat recovery heat exchanger recovers the exhaust gas exhaust heat exhausted from the engine by recovering the exhaust gas exhaust heat after passing through the engine coolant heating heat exchanger by heat exchange with the refrigerant. absorption heat pump system according to claim 1 or 2 is disposed on the downstream side of the engine cooling water heated heat exchanger of the exhaust passage.

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