JP3159038B2 - Absorption heat pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ammonia absorption heat pump system using ammonia as a refrigerant and ammonia as an absorbent, and more particularly to a small-sized apparatus used for home use.

[0002]

2. Description of the Related Art Conventionally, this type of absorption heat pump is not for domestic use but is for business use. As shown in FIG. 11 which shows a system diagram at the time of cooling, a generator and a rectifier are integrally formed. A condenser 51 having a refrigerant flow path on the primary side and a cooling water flow path on the secondary side;
A refrigerant tank 52 provided at the outlet, a subcooler 53,
An expansion valve 54; an evaporator 55 having a refrigerant flow path on the primary side and a cold water flow path on the secondary side; a solution heat exchanger 56;
An absorber 58 having a refrigerant flow path on the primary side and a cooling water flow path on the secondary side, a concentrated solution tank 59 provided at the outlet of the absorber refrigerant flow path, a solution pump 60, and A refrigerant circuit 61 to be connected; a cooling water circuit 62 connecting the secondary cooling water flow paths of the condenser and the absorber;
And a chilled water circuit 63 including a secondary chilled water circuit. Generally, a portion surrounded by a dashed line is incorporated in the outdoor unit.

During cooling, the cold water in the cold water circuit 63 is circulated to the indoor radiator 65 using the cold water circulation pump 64, and the hot water in the cooling water circuit 62 is circulated to the outdoor unit radiator 67 using the hot water circulation pump 66. At the time of heating, the chilled water in the chilled water circuit 63 is circulated to the outdoor radiator 67, and the warm water in the chilled water circuit 62 is circulated to the indoor unit radiator 65. Switching of the flow path at the time of cooling / heating is performed using, for example, a switching valve. In FIG. 11, the switching valve is omitted.

[0004] The expansion valve used here is generally
Instead of a simple capillary tube, the opening was fixed. In the case of an electric compression heat pump using Freon as the working medium, for example, as shown in FIG. 12, the refrigerant temperature at the outlet of the evaporator 68 is changed to the valve 70 by a change in the volume of the liquid in the temperature-sensitive cylinder 69. A mechanical type that operates by converting a change in temperature and pressure into mechanical energy, such as a temperature-type automatic expansion valve 73 that operates a directly connected bellows 71 and a holding rod 72, and a pressure-type automatic expansion valve, has been used. .

[0005]

However, when a capillary tube is used as an expansion valve, the degree of opening as a so-called expansion valve is constant. Outside temperature, capacity, etc)
It is not possible to perform detailed ability control corresponding to The opening degree of the expansion valve is, of course, set to an opening degree that ensures the circulation amount of the refrigerant (here, the refrigerant means ammonia) corresponding to the maximum capacity. This is because it is necessary to change the opening.

Further, an expansion valve used in an electric compression system cannot be used as it is in an ammonia absorption heat pump. The latent heat of vaporization of ammonia is about 10 times that of chlorofluorocarbons, and if the same performance is to be obtained, the circulation amount is about 1/10. Therefore, it is necessary to change the shape of the valve seat that receives the valve, and it is necessary to finely control the valve opening.
This is because even a small change in the valve opening degree causes a large change in the evaporation temperature in the case of ammonia, which adversely affects performance and operation.

[0007]

According to the present invention, a regenerator, a rectifier, a condenser, an expansion valve,
A refrigerant circuit formed by connecting a primary side of an evaporator, an absorber, and a solution pump to a pipe, a chilled water circulation circuit formed on a secondary side of the evaporator, and a secondary circuit formed on a secondary side of the condenser. A hot water circulation circuit, pressure detecting means for detecting an evaporating pressure at the inlet of the evaporator, and control means for controlling an opening of the electronically controlled expansion valve in accordance with a pressure detected by the pressure detecting means.

According to the present invention, since the opening of the expansion valve is controlled in accordance with the pressure detected by the pressure detecting means, fine opening control can be realized in accordance with a change in the evaporation pressure.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The absorption heat pump of the present invention
A regenerator, a rectifier, a condenser, an expansion valve, a primary side of an evaporator, an absorber, a refrigerant circuit formed by connecting a solution pump to a pipe, and a secondary side of the evaporator. A cold water circulation circuit, a hot water circulation circuit formed on the secondary side of the condenser, a pressure detection means for detecting an evaporating pressure at an inlet of the evaporator, and the electronic device according to a detection pressure of the pressure detection means. The control valve has a control means for controlling the opening degree of the expansion valve, and the opening degree of the expansion valve is controlled in accordance with the pressure detected by the pressure detecting means. Control can be realized.

The control means includes a target value setting means for setting a target value of the evaporating pressure, and the electronic control expansion valve so that the pressure detected by the pressure detecting means coincides with the target value set by the target value setting means. With the configuration including the output setting means for outputting the electric signal, it is possible to set the target value of the evaporation pressure of the refrigerant and control the opening degree of the electronically controlled expansion valve so as to match the target value.

[0011] The absorption heat pump of the present invention is a refrigerant formed by connecting a regenerator, a rectifier, a condenser, an expansion valve, a primary side of an evaporator, an absorber, and a solution pump with piping. A circuit, a cold water circulation circuit formed on the secondary side of the evaporator, and a hot water circulation circuit formed on the secondary side of the condenser,
Pressure detection means for detecting the evaporation pressure at the evaporator inlet, chilled water temperature detection means for detecting the chilled water temperature of the chilled water circulation circuit, and according to the detected pressure of the pressure detection means and the detected temperature of the chilled water temperature detection means The electronic control expansion valve includes a control unit that controls an opening degree of the electronic control expansion valve. Based on a pressure detected by the pressure detection unit and a temperature detected by the chilled water temperature detection unit, the control unit controls the opening degree of the electronic control expansion valve. Can be controlled.

The control means sets a target value of the evaporating pressure in accordance with the temperature detected by the chilled water temperature detecting means, and the detected pressure of the pressure detecting means coincides with the target value set by the target value setting means. With the configuration having output setting means for outputting an electric signal to the electronic expansion valve, the opening degree of the electronic expansion valve can be controlled so that the evaporating pressure changes in conjunction with the change in chilled water temperature. it can.

[0013] The absorption heat pump of the present invention is a refrigerant comprising a regenerator, a rectifier, a condenser, an expansion valve, a primary side of an evaporator, an absorber, and a solution pump connected by piping. A circuit, a cold water circulation circuit formed on the secondary side of the evaporator, and a hot water circulation circuit formed on the secondary side of the condenser,
Pressure detection means for detecting the evaporation pressure at the evaporator inlet, outside air temperature detection means for detecting the outside air temperature, switching means for performing indoor air conditioning by the hot water circulation circuit during heating, and the cold water circulation circuit during cooling. In heating, the control unit controls the opening degree of the electronically controlled expansion valve in accordance with the detected pressure of the pressure detection unit and the detected temperature of the outside air temperature detection unit, and the temperature detected by the outdoor temperature detection unit The opening degree of the electronically controlled expansion valve can be controlled by the control means based on the pressure detected by the pressure detection means.

Further, the control means includes a target value setting means for setting a target value of the evaporating pressure in accordance with the temperature detected by the outside air temperature detecting means, and an electronic control unit so that the detected pressure of the pressure detecting means coincides with the target value setting means. With the configuration including the output setting means for outputting an electric signal to the expansion valve, the opening of the electronic expansion valve can be controlled so that the evaporation pressure changes in accordance with the change in the outdoor temperature.

Further, the absorption heat pump of the present invention has a structure in which the pressure detecting means is assembled inside the housing of the expansion valve, so that the handling becomes easy and the accurate evaporation pressure can be detected.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) In FIG. 1, a refrigerant circuit 4 in which a gas supplied from a gas solenoid valve 1 and a refrigerant heated by a burner 3 by air supplied from a burner fan 2 circulates is provided with a regenerator 5 and a rectifier. The primary side of the condenser 6, the condenser 7, the primary side of the subcooler 8, the electronic control expansion valve 9, the primary side of the evaporator 10, the secondary side of the subcooler 8, the primary side of the absorber 11, the solution The pump 12 and the primary side of the solution heat exchanger 13 are sequentially connected by piping. The lower part of the rectifier 6, the secondary side of the solution heat exchanger 13, the pressure reducing valve 14, and the primary side of the absorber 11 are connected by piping to the refrigerant rarely separated from the refrigerant gas by the rectifier 6. A solution flow path is formed. The chilled water circulation circuit 15 in which the chilled water cooled by exchanging heat with the refrigerant in the evaporator 10 circulates,
0, a first circulating pump 16 and an indoor heat exchanger 18 having an indoor fan 17 are sequentially connected by piping. Further, a hot water circulation circuit 19 in which hot water heated by exchanging heat with the refrigerant in the condenser 7 circulates is provided with a secondary side of the condenser 7, a secondary side of the absorber 11, a second circulation pump 20, an outdoor radiating fan 21. Are sequentially connected by piping. And the evaporator 10
A pressure detecting means 23 for detecting the evaporating pressure of the refrigerant is provided in the pipe at the inlet on the primary side. A control unit 24 controls the opening of the electronically controlled expansion valve 9 in accordance with the pressure detected by the pressure detection unit 23.

Next, the operation of the above configuration will be described.
First, the operation of the refrigerant circuit 4 will be described. The refrigerant vapor heated by the burner 3 is separated by the rectifier 6 into a high-purity refrigerant gas and a low-concentration refrigerant dilute solution. The refrigerant gas generated from the rectifier 6 is sent to the primary side of the condenser 7, where it exchanges heat with water flowing through the secondary side circuit to be condensed and liquefied. After the liquefied liquid refrigerant is cooled by the supercooler 8, it passes through the electronically controlled expansion valve 9 to be decompressed and undergo an adiabatic expansion action. The decompressed liquid refrigerant is sent to the primary side of the evaporator 10, where it evaporates and gasifies by heat exchange with water passing through the secondary side. The gasified refrigerant is sent to the absorber 11 heated by the supercooler 8.

On the other hand, the refrigerant dilute solution generated in the rectifier 6 is cooled in the solution heat exchanger 13 and then depressurized by passing through the pressure reducing valve 14 and sent to the primary side of the absorber 11. . On the primary side of the absorber 11, the refrigerant gas is absorbed by the refrigerant dilute solution and changes to a refrigerant concentrated solution having a higher concentration than the refrigerant dilute solution. A part of the refrigerant concentrated solution is heated by the solution heat exchanger 13 by the solution pump 12 and then sent to the regenerator 5. Further, the solution pump 12 is configured to pump a part of the concentrated solution to the rectifier 6 under pressure.

Next, the operation of the chilled water circulation circuit 15 will be described. The cold water cooled by exchanging heat with the refrigerant on the primary side of the evaporator 10 is pumped to the indoor heat exchanger 18 by the first circulation pump 16, where it exchanges heat with indoor air to perform a cooling operation. Next, the operation of the hot water circulation circuit 19 will be described. 1 of condenser 7
The hot water heated by heat exchange with the secondary refrigerant and the primary refrigerant of the absorber 11 is heated by the second circulation pump 20 to the outdoor heat exchanger 22.
Where the heat is released to the outside air.

Next, the operation of the electronically controlled expansion valve 9 will be described with reference to FIG. FIG. 2 is a sectional view of the electronically controlled expansion valve.
9a is a needle for controlling the opening degree of the throttle portion 9b of the flow path;
c is a pulse motor for moving the needle 9a in the vertical direction. The flow rate of ammonia flowing inside the electronically controlled expansion valve 9 is controlled by a needle 9a that moves up and down in accordance with the rotational force generated by the pulse motor 9c.

Next, the relationship between the opening degree of the electronic control expansion valve 9 and the evaporation pressure of the refrigerant will be described. Since the flow rate of the refrigerant flowing into the evaporator 10 increases by increasing the opening degree of the electronic control expansion valve 9, the concentration of the concentrated solution at the outlet of the absorber 11 decreases, and as a result, the evaporator 8 and the absorber 10 , The pressure in the low pressure line increases. Therefore, the refrigerant works so that the evaporating pressure of the refrigerant increases as the pressure in the low-pressure line increases.
Conversely, when the opening of the electronically controlled expansion valve 9 is reduced, the refrigerant evaporating pressure acts to decrease. In order to stabilize the refrigeration cycle, it is necessary to control the valve opening so that the evaporation pressure is set in an appropriate range. Therefore, if the evaporation pressure is too high, control is performed so that the valve opening is reduced to reduce the evaporation pressure, and if the evaporation pressure is too low, the valve opening is increased and the evaporation pressure is increased. Just do it.

In view of this, the control means 24 stores the relationship of the valve opening in accordance with the pressure detected by the pressure detecting means 23, that is, the relationship in which the valve opening is reduced as the pressure rises. A rotation signal is supplied to the pulse motor 9c so as to give a valve opening corresponding to the pressure detected every time. According to the rotation signal given here, the needle 9a
Operates to change the valve opening.

According to the above configuration, the control means 24 controls the electronically controlled expansion valve 9 in accordance with the pressure detected by the pressure detection means 23.
Since the opening degree of the refrigerant is controlled, the evaporation pressure range of the refrigerant can be kept in an appropriate range, and the refrigerant cycle can be stabilized.

(Embodiment 2) FIG. 3 is a block diagram of Embodiment 2 of the present invention. In FIG. 3, the control means 24 different from the first embodiment.
Will be described. Reference numeral 25 denotes a target value setting means for setting a target value of the evaporation pressure at the entrance of the evaporator 10. Reference numeral 26 denotes an output setting means for setting the valve opening of the electronically controlled expansion valve 9 so that the target value of the evaporation pressure determined by the target value setting means coincides with the detected pressure of the pressure detecting means 23. That is, the pressure P detected by the pressure detecting means 23 is changed every appropriate sampling time.
j, and reads the target value Ps determined by the target value setting means 25.
The output is set by PI control, PID control, or the like in accordance with the temperature deviation ΔP = Ps−Pj. For example, P
When I control is used, as described in the first embodiment,
If the evaporating pressure Pj increases, the valve opening degree may be reduced so that the relational expression between the valve opening degree S and the temperature deviation ΔP is as shown in Equation 1.

S = K1 + K2 × ΔP + K3 × ΣΔP Expression 1 Here, K1, K2, and K3 are positive constants.

According to the above configuration, the target value of the evaporation pressure is fixed. For example, during the cooling operation, a method of keeping the temperature of the chilled water at the outlet on the secondary side of the evaporator 10 at around 7 ° C. is generally adopted. However, in order to exchange heat with the chilled water at 7 ° C.,
The inlet temperature on the primary side of the evaporator 10 is lower than 3 to 4 ° C.
Must be kept back and forth. Therefore, the pressure corresponding to this temperature is set in the target value setting means 25, and if a pressure deviation occurs, the valve opening changes, so that a constant pressure is always obtained.

(Embodiment 3) FIG. 4 shows an example of an electronically controlled expansion valve 7 used in each of Embodiments 1 and 2. In FIG. 4, the pressure detecting means 23 is incorporated inside the electronically controlled expansion valve 9. In FIG. 4, the pressure detecting means 23 is in contact with the outlet side flow path inside the electronically controlled expansion valve 9, and can detect the refrigerant pressure immediately after receiving the expansion action.

According to the above configuration, pressure loss and heat loss are extremely small, and more accurate pressure detection becomes possible. The electronically controlled expansion valve 9 may be used in each of the embodiments described below.

(Embodiment 4) FIG. 5 differs from Embodiment 1 in the point that a chilled water temperature detecting means 27 is provided in the chilled water circulation circuit 15 and the configuration of the control means 24. The chilled water temperature detecting means 27 is provided on a pipe at a secondary outlet of the evaporator 10. The control means 24 sets the opening of the electronically controlled expansion valve 9 according to the detection values of the pressure detection means 23 and the chilled water temperature detection means 25. That is, the magnitude of the chilled water load of the chilled water circulation circuit 27 is estimated based on the chilled water temperature, and the opening of the electronic control expansion valve 9 is set in consideration of the load information. In order to exhibit the refrigerating capacity corresponding to the load, it is necessary to increase the refrigerant circulation amount as the load increases. Therefore, it is necessary to increase the opening of the electronically controlled expansion valve 9 as the load increases. If the chilled water temperature is high, the load can be determined to be large. Therefore, when the chilled water temperature is high and the evaporation pressure is low, the opening of the electronic control expansion valve 9 is large. Conversely, when the chilled water temperature is low and the evaporation pressure is high, the electronic control is performed. The opening degree of the expansion valve 9 may be small.
Therefore, the control means 24 stores the opening degree of the electronically controlled expansion valve 9 corresponding to the combination of the detected pressure of the pressure detecting means 23 and the detected temperature of the chilled water temperature detecting means 27, and reads the opening degree at an appropriate sampling time. , Output to the electronic control expansion valve 9. FIG. 6 shows the relationship between the evaporation pressure and the electronic control expansion valve opening degree with the evaporation temperature as a parameter. In FIG. 6, Te is the cold water temperature,
There is a relationship of 1 <Te2 <Te3.

According to the above configuration, an appropriate valve opening can be obtained in response to a change in chilled water temperature, so that the refrigerant cycle can be stabilized without being affected by a change in chilled water load.

(Embodiment 5) FIG. 7 differs from Embodiment 4 in the configuration of the control means 24. The target value setting unit 25 detects the chilled water temperature Te detected by the chilled water temperature detecting unit 27.
The target value of the evaporating pressure is changed in conjunction with the value of. That is, if the cold water temperature Te is high, the target value Ps of the evaporation pressure
Is also large. The output setting means 26 is provided for the evaporating temperature detecting means 23.
Of the electronic control expansion valve 8 is set such that the detected temperature of the electronic control expansion valve 8 coincides with the target value Ps. That is, the detection pressure Pj of the evaporating temperature detection means 23 and the detection temperature of the chilled water temperature detection means 25 are read at appropriate sampling times, and the pressure deviation ΔP = Ps−P from the target value Ps determined by the target value setting means 25 is read.
According to j, the output is set by PI control, PID control or the like. For example, when the PI control is used, the control expression is expressed in the same manner as Expression 1 described in the second embodiment.

According to the above configuration, the target value of the evaporating pressure changes with the change of the chilled water load. Therefore, when the load of the chilled water changes, the temperature of the chilled water circulation circuit and the refrigerant circuit are maintained and the temperature of the chilled water circuit is gradually balanced, and the refrigerant cycle can be stabilized.

(Embodiment 6) FIG. 8 is different from Embodiment 1 in that the first switching valve 29 and the second switching valve 30
In addition, by the action of these switching valves, indoor air conditioning is performed by the secondary circuit of the evaporator 10 during cooling, and indoor air conditioning is performed by the secondary circuit of the condenser 8 during heating, thereby enabling cooling and heating. The point, the point that the outdoor temperature exchanger 31 is provided in the outdoor heat exchanger 22, and the configuration of the control unit 24.

During the heating operation, the hot water obtained on the secondary side of the condenser 7 passes through the first switching valve 29 and the first circulating pump 16, and exchanges heat with the indoor air in the indoor heat exchanger 18, so that the room is heated. After heating, the condenser 7 passes through the second switching valve 30.
Return to On the other hand, the cold water obtained on the secondary side of the evaporator 10 passes through the first switching valve 29 and the second circulating pump 20 and exchanges heat with outdoor air in the outdoor heat exchanger 22.
Return to At the time of the heating operation, the outside air temperature needs to correspond to about −10 ° C. to about 10 ° C., but in order to realize the heat pump operation, the evaporation temperature needs to be controlled in a range of about −20 ° C. to about 0 ° C. That is, in order to perform a high-efficiency heating operation corresponding to the outside temperature, it is necessary to lower the evaporation temperature by reducing the opening degree of the electronically controlled expansion valve and the evaporation pressure as the outside temperature decreases. . Therefore, when the outside air temperature is high and the evaporation pressure is low, the opening of the electronic control expansion valve 9 is large, and conversely, when the outside air temperature is low and the evaporation pressure is high, the opening of the electronic control expansion valve 9 may be small. . Therefore, the control unit 24 stores the opening degree of the electronically controlled expansion valve 9 corresponding to the combination of the detected pressure of the pressure detecting unit 23 and the detected pressure of the outside air temperature detecting unit 31, and reads the opening at appropriate sampling times. , Output to the electronic control expansion valve 9. FIG. 9 shows the relationship between the evaporation pressure and the opening degree of the electronic control expansion valve with the outside air temperature To as a parameter. In FIG. 9, To is the outside air temperature, and To1 <To
There is a relationship of 2 <To3.

According to the above configuration, an appropriate valve opening can be obtained in response to a change in the outside air temperature during the heating operation, so that a highly efficient heat pump operation is possible.

(Embodiment 7) FIG. 10 differs from Embodiment 6 in the configuration of the control means 24. The target value setting means 25 changes the target value of the evaporation pressure in conjunction with the value of the outside air temperature To detected by the outside air temperature detecting means 31. That is, if the outside air temperature To is high, the target value Ps of the evaporation pressure is also high. The output setting means 26 sets the valve opening of the electronically controlled expansion valve 9 so that the pressure detected by the pressure detecting means 23 matches the target value Ps. That is, the detection pressure Pj of the pressure detection means 23 and the detection temperature To of the outside air temperature detection means 25 are read at appropriate sampling times, and the temperature deviation ΔT = Ps−Po from the target value Ps determined by the target value setting means 25 is obtained. Therefore, the output is set by PI control, PID control, or the like. For example, when the PI control is used, the control expression is expressed in the same manner as Expression 1 described in the second embodiment.

According to the above configuration, an appropriate valve opening can be obtained in response to a change in the outside air temperature during the heating operation, so that a highly efficient heat pump operation is possible.

[0038]

As described above, the absorption heat pump of the present invention controls the degree of opening of the electronically controlled expansion valve in accordance with the evaporating pressure detected by the pressure detecting means, thereby realizing fine-grained control. There is an effect that can be.

Further, since the evaporation pressure changes according to the temperature of the cold water, a stable operation can be realized even when the load changes.

Further, during the heating operation, the evaporating pressure changes in accordance with the change in the outside air temperature, so that a highly efficient heat pump operation can be performed in response to a wide temperature change.

Further, since the pressure detecting means is provided inside the housing of the electronically controlled expansion valve, more accurate control of the evaporating pressure becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an absorption heat pump in Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of the electronically controlled expansion valve according to the first embodiment.

FIG. 3 is a configuration diagram of an absorption heat pump in Embodiment 2 of the present invention.

FIG. 4 is a sectional view of an electronically controlled expansion valve according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of an absorption heat pump according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the pressure detection means and the opening degree of the electronically controlled expansion valve in the fourth embodiment.

FIG. 7 is a configuration diagram of an absorption heat pump in Embodiment 5 of the present invention.

FIG. 8 is a configuration diagram of an absorption heat pump according to a sixth embodiment of the present invention.

FIG. 9 is a diagram showing the relationship between the pressure detection means and the opening degree of the electronically controlled expansion valve in the sixth embodiment.

FIG. 10 is a configuration diagram of an absorption heat pump according to a seventh embodiment of the present invention.

FIG. 11 is a configuration diagram showing a conventional absorption heat pump.

FIG. 12 is a sectional view showing a conventional expansion valve.

[Explanation of symbols]

 Reference Signs List 4 refrigerant circuit 5 regenerator 6 rectifier 7 condenser 9 electronically controlled expansion valve 10 evaporator 11 absorber 12 solution pump 15 cold water circulation circuit 19 hot water circulation circuit 23 pressure detection means 24 control means

Continuation of the front page (72) Inventor Takashi Sawada 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-61-280357 (JP, A) JP-A-59-183261 (JP) , A) JP-A-8-313104 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 15/00 306 F25B 15/04

Claims (7)

(57) [Claims] A refrigerant circuit comprising a pipe connecting a regenerator, a rectifier, a condenser, an expansion valve, a primary side of an evaporator, an absorber, and a solution pump; A cold water circulation circuit formed on the secondary side, a hot water circulation circuit formed on the secondary side of the condenser, pressure detection means for detecting an evaporation pressure at the evaporator inlet, and pressure detected by the pressure detection means An absorption heat pump having control means for controlling an opening degree of the electronically controlled expansion valve in accordance with the condition. A control means for setting a target value of the evaporation pressure; and a control means for controlling the electronic control expansion valve so that a detection pressure of the pressure detection means coincides with a target value set by the target value setting means. 2. The absorption heat pump according to claim 1, further comprising output setting means for outputting an electric signal. 3. A refrigerant circuit formed by connecting a regenerator, a rectifier, a condenser, an expansion valve, a primary side of an evaporator, an absorber, and a solution pump to a pipe, A cold water circulation circuit formed on the secondary side, a hot water circulation circuit formed on the secondary side of the condenser, pressure detection means for detecting an evaporation pressure at the evaporator inlet, and a cold water temperature of the cold water circulation circuit And a control means for controlling an opening degree of the electronically controlled expansion valve according to a detected pressure of the pressure detecting means and a detected temperature of the chilled water temperature detecting means. 4. A control means comprising: a target value setting means for setting a target value of an evaporation pressure according to a temperature detected by a chilled water temperature detection means;
4. An absorption heat pump according to claim 3, further comprising output setting means for outputting an electric signal to the electronic expansion valve such that the pressure detected by the pressure detecting means matches the target value set by the target value setting means. 5. A refrigerant circuit comprising piping connected to a regenerator, a rectifier, a condenser, an expansion valve, a primary side of an evaporator, an absorber, and a solution pump. A cold water circulation circuit formed on the secondary side, a hot water circulation circuit formed on the secondary side of the condenser, a pressure detecting means for detecting an evaporation pressure at the evaporator inlet, and an outside air temperature for detecting an outside air temperature Detecting means, switching means for performing the indoor air-conditioning by the cold water circulating circuit at the time of cooling, the hot water circulation circuit at the time of heating, and according to the detection pressure of the pressure detection means and the detection temperature of the outside air temperature detection means at the time of heating. An absorption heat pump having control means for controlling an opening degree of the electronic control expansion valve. 6. The control means includes a target value setting means for setting a target value of the evaporating pressure in accordance with a temperature detected by the outside air temperature detection means, and an electronic control unit for controlling the detected pressure of the pressure detection means to be equal to the target value setting means. 6. The absorption heat pump according to claim 5, further comprising output setting means for outputting an electric signal to the expansion valve. 7. An absorption heat pump according to claim 1, wherein the expansion valve has a pressure detecting means built in the housing.