JPH09318185A - Absorption heat pump and its operating method - Google Patents

Abstract

(57) Abstract: An absorption heat pump that uses the heat of the outside air can be continuously operated even when the outside air temperature drops below a planned temperature during operation of the heat pump. SOLUTION: A pipe 67 for guiding a liquid refrigerant to an evaporator is provided with a three-way valve 66 having one inlet and two outlets, one outlet is connected to the evaporator, and the other outlet is connected to a solution spraying device of an absorber. . During the heating operation, when the outside air temperature falls below a preset temperature, the three-way valve 66 is operated to guide the liquid refrigerant to the solution spraying device 51 of the absorber instead of to the evaporator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption heat pump, and more particularly to an absorption heat pump using water-ammonia as a working medium and a method of operating the same.

[0002]

2. Description of the Related Art FIG. 2 shows a generally well-known air conditioner using an absorption heat pump using water-ammonia as a working medium. The air-conditioning apparatus shown in the figure is generated by a regenerator unit 31 for separating a strong solution into a refrigerant vapor and a weak solution, a condenser 32 for condensing and liquefying the refrigerant vapor separated by the regeneration unit 31, and a condenser 32. Expansion valve 34 for liquid refrigerant
Absorption heat pump including an evaporator 35 that is introduced via a heat medium and evaporates by heat exchange with a heat medium, and an absorption unit 36 that absorbs the refrigerant vapor evaporated in the evaporator 35 into the weak solution. And an indoor air heat exchanger 64 and an outdoor air heat exchanger 65 which are connected to the absorption heat pump via a heating / cooling switching device 63 by a heat medium circuit.

The regenerator unit 31 of the absorption heat pump
Is a decomposing device 42, a rectifying device 41 arranged in order from the top,
A weak solution heat exchanger 40 and a regenerative heat input device 39, and a regenerator unit container 31a in which they are installed,
The lower end of the weak solution heat exchanger 40 has a regenerator unit container 31a.
Attached to the bottom of. Further, the condenser 32 is of a tubular body type in which the heat exchanger 45 forming the refrigerant passage is the tube side passage and the heat medium passage is the body side passage, and the upper end of the regenerator unit container 31a is It is connected to the upper end (entrance side) of the heat exchanger 45 installed in the vessel 32.

The absorption unit 36 includes a solution spraying device 51, an absorption heat recovery heat exchange section 52, an absorption heat radiating section 53, an absorption unit container 36a in which they are installed, and a bottom of the absorption unit container 36a. The solution circulating pump 37 is connected to the suction side, and the outlet side of the solution circulating pump 37 is connected to the upper end (inlet side) of the partial condenser 42. Further, the upper end (outlet side) of the absorbed heat recovery heat exchange part 52 is connected to the position of the rectifier 41 of the regenerator unit container 31a, and the lower end (inlet side) of the absorbed heat recovery heat exchange part 52 is a dephlegmator. It is connected to the lower end (outlet side) of 42.
Further, the weak solution heat exchanger 40 of the regenerator unit 31.
The upper end (outlet side) of the solution spraying device 51
The upper end (outlet side) of the absorption heat radiating portion 53 is connected to the lower end of the condenser 32 on the body side.

The evaporator 35 is a heat exchanger 4 forming a refrigerant flow path.
8 is a tube body type in which the tube side channel and the heat medium channel are the body side channels,
The lower end (outlet side) of the heat exchanger 45 installed in the condenser 32 is connected to the upper end (inlet side) of the heat exchanger 48 by the liquid refrigerant pipe 67 via the expansion valve 34. The lower end (outlet side) of the heat exchanger 48 is connected to the lower part of the absorption unit container 36a.

The cooling / heating switching device 63 has eight ports A,
It is a flow path switching valve having B, C, D, E, F, G, and H, and port A is located below the body side of the evaporator 35 via the heat medium circulation pump 62, and port B is the body side of the evaporator 35. Port C on top
Is connected to the lower end (entrance side) of the absorption heat radiator 53 of the absorption unit 36 via the heat medium circulation pump 61, and the port D is connected to the upper side of the condenser 32 on the body side. The heat medium circulation pump 62 is arranged such that the suction side is connected to the port A and the heat medium circulation pump 61 is connected to the port C on the suction side. The cooling / heating switching device 63 sets ports A and B to ports E and F and ports C and D to ports G and H during cooling.
And ports A and B are communicated with ports G and H, and ports C and D are communicated with ports E and F, respectively. Although an eight-way valve is used as the cooling / heating switching device 63 in this example, a combination using two four-way valves or four three-way valves may be used.

The indoor air heat exchanger 64 is arranged such that both ends thereof are connected to the ports E and F of the cooling / heating switching device 63, and the outdoor heat exchanger 65 is connected to both ports G and H of the cooling / heating switching device 63. Are arranged. Further, the indoor air heat exchanger 64, the outdoor air heat exchanger 65, the absorption heat radiator 53,
An antifreezing liquid such as water or an ethylene glycol aqueous solution is filled as a heat medium in a circulation system formed of the condenser barrel side, the cooling / heating switching device 63 and a pipe connecting them.

The regenerator unit 31 includes the solution circulation pump 3
The strong solution (solution with high refrigerant concentration) 43a supplied from 7 through the dephlegmator 42 and the absorption heat recovery heat exchange section 52 is separated into refrigerant vapor and weak solution (solution with low refrigerant concentration), and the refrigerant vapor is separated. The weak solution is sent to the heat exchanger 45 of the condenser 32 to the weak solution heat exchanger 40 in which the weak solution is internally housed.

The condenser 32 cools and condenses the refrigerant vapor sent from the regenerator unit 31 into the heat exchanger 45 installed therein by the heat medium flowing to the shell side to form a liquid refrigerant. The generated liquid refrigerant is guided through the expansion valve 34 to the heat exchanger 48 incorporated in the evaporator 35, and while passing through the heat exchanger 48, the heat of the heat medium flowing on the cylinder side is taken and evaporated. The evaporated refrigerant vapor is introduced into the bottom of the absorption unit container 36a.

The strong solution accumulated at the bottom of the absorption unit container 36a is increased in pressure by the solution circulation pump 37, heated up through the partial condenser 42 of the regenerator unit 31, and further absorbed heat recovery heat exchange section of the absorption unit 36. It is introduced into the heat exchange channel from the lower inlet of 52. Absorption heat recovery heat exchange section 52
The strong solution that has passed through is introduced into the middle stage of the rectifier 41 of the regenerator unit 31. The weak solution separated by the regeneration process of the regenerator unit 31 and accumulated at the bottom of the regenerator unit container 31a passes through the weak solution heat exchanger 40 and the pressure reducing valve 57 and is provided on the top of the absorption unit 36. 5
1 is supplied.

The operation of the air conditioner thus configured will be described below. The weak solution introduced to the top of the absorption unit container 36a is sprayed inside the container (body side) by the solution spraying device 51. The sprayed solution flows down along the outer surface of the heat transfer wall of the absorption heat recovery heat exchange section 52,
Or fall in the space. In the process, the solution comes into contact with and absorbs the refrigerant vapor that has passed through the absorbing and radiating portion 53, whereby the refrigerant concentration of the solution is gradually increased. The absorption heat generated by the absorption of the refrigerant vapor is taken into the strong solution flowing inside the absorption heat recovery heat exchange section 52 and used as a part of the heat necessary for the regeneration.

The solution that has passed through the area of the absorbed heat recovery heat exchange section 52 flows down along the outer surface of the heat transfer wall of the absorbed heat radiating section 53, or drops in the space. In the process, the solution comes into contact with the refrigerant vapor introduced into the absorption container and absorbs it, thereby further increasing the refrigerant concentration of the solution. The absorbed heat generated at this time is taken into the heat medium flowing in the heat exchange channel of the absorbed heat radiating section 53. The solution that has passed through the absorption heat radiating section 53 becomes a low temperature strong solution and accumulates at the bottom of the absorption unit container 36a.

The strong solution accumulated at the bottom of the absorption unit container 36a is pressurized by the solution circulation pump 37, introduced into the heat exchange passage of the dephlegmator 42 and heated, and then the absorption heat recovery heat It is introduced into the heat exchange flow path of the absorbed heat recovery heat exchange section 52 from the lower inlet of the exchange section 52. The strong solution introduced into the heat exchange channel flows toward the upper part, is heated by the above-mentioned absorption heat as it approaches the upper outlet and rises in temperature, starts boiling when it reaches the saturation temperature, and further raises the temperature of the refrigerant. Decrease the concentration.

The strong solution which has become a gas-liquid two-phase flow due to boiling in the absorption heat recovery heat exchange section 52 is absorbed by the absorption heat recovery heat exchange section 5.
2 is sent to the rectifier 41 of the regenerator unit 31 from the upper outlet. The two-phase strong solution introduced into the rectifier 41 is separated into a refrigerant vapor and a weak solution. The refrigerant vapor increases in concentration in the process of rising in the rectifier 41, undergoes heat exchange with a low-temperature strong solution in the dephlegmator 42 to be partially condensed and refluxed, and then supplied to the condenser 32. On the other hand, the strong solution has a reduced refrigerant concentration in the process of descending the rectifier 41, and becomes a weak solution when passing through the outer surface of the weak solution heat exchanger 40 and the outer surface of the regenerative heat input device 39 to become a regenerator unit. Collect at the bottom of the container 31a. The weak solution collected at the bottom of the regenerator unit container 31a is supplied to the solution spraying device 51 at the top of the absorption unit 36 via the internal flow path of the weak solution heat exchanger 40 and the pressure reducing valve 57 as described above.

In this way, the absorption step and the regeneration step are repeated, and in the process, cold heat or hot heat is taken out of the system from the evaporator 35, the condenser 45 or the absorption / radiation section 53.

In the air conditioner having the above-described structure, during cooling operation, the absorption / radiation section 53 and the trunk side of the condenser 32 are connected to the outdoor heat exchanger 65 via the cooling / heating switching device 63. The heat of the heat absorbing / dissipating portion 53 and the heat exchanger 45 of the condenser 32 is taken out by the heat medium circulating by being driven by the heat medium circulation pump 61, and is released to the atmosphere by the outdoor air heat exchanger 65. At the same time, the body side of the evaporator 35 is connected to the indoor heat exchanger 64 via the cooling / heating switching device 63, and the heat medium cooled by being deprived of heat by the refrigerant evaporated in the heat exchanger 48 is the heat medium. It is driven by the circulation pump 62, is sent to the indoor heat exchanger 64, and is used for cooling the indoor air. That is, the indoor heat exchanger 64
At, the heat of the indoor air is taken out, and the heat is released to the atmosphere by the outdoor air heat exchanger 65.

On the other hand, during heating operation, the absorption / radiation unit 53 and the body side of the condenser 32 are connected to the indoor heat exchanger 65 via the cooling / heating switching device 63, and the absorption / radiation unit 53 and the heat exchanger 45 of the condenser 32 are connected. Is taken out by the circulating heat medium driven by the heat medium circulation pump 61, sent to the indoor heat exchanger 65, and used for heating the indoor air. At the same time, the evaporator 35
The outside of the heat exchanger 64 is connected to the trunk side of the
The heat medium cooled by being deprived of heat by the refrigerant evaporated in the heat exchanger 48 is heated by the heat of the outdoor air.

[0018]

In the above conventional technique, during heating operation, the barrel side of the evaporator 35 and the outdoor heat exchanger 65 are provided.
The heat medium that circulates between the two is taken in by the heat from the outside air, so that the heat medium is deprived of the heat by the refrigerant evaporated in the heat exchanger 48 and cooled to a temperature lower than the outside air temperature. On the contrary, unless the temperature becomes lower than the outside air temperature, heat is released to the outside air. For this reason, when the outside air temperature falls below the planned temperature, there is a possibility that the heat medium cooled to a temperature lower than the outside air temperature may freeze, and there is a possibility that the operation cannot be performed.

An object of the present invention is to enable continuous operation of an absorption heat pump utilizing the heat of the outside air even if the outside air temperature drops below a planned temperature during operation of the heat pump.

[0020]

In order to solve the above-mentioned problems, the present invention condenses and liquefies a regenerator unit for separating a strong solution into a refrigerant vapor and a weak solution, and the refrigerant vapor separated by the regeneration unit. A condenser, an evaporator that introduces the liquid refrigerant generated in the condenser through an expansion valve and evaporates by heat exchange with a heat medium, and a refrigerant vapor evaporated in the evaporator is absorbed by the weak solution. In an absorption heat pump including an absorption unit, a flow path switching means having at least two outlet sides is provided in the liquid refrigerant pipe on the downstream side of the expansion valve, and one outlet of the flow path switching means is the evaporator. In addition, the other outlet is connected to the upper part of the absorption unit.

The flow path switching means may be constituted by using a three-way valve, and a Y-shaped branch pipe having one end connected to the expansion valve outlet side and the other two Y-shaped branch pipes. You may comprise including the on-off valve each connected to the edge part.

Further, the absorption unit comprises a solution spraying device arranged above the absorption heat recovery heat exchange section, and the liquid refrigerant introduced through the flow path switching means is guided to the solution spraying device to spray the solution. After being mixed with the weak solution in the apparatus, it is desirable that the solution is dropped into the absorption heat recovery heat exchange section.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system diagram of an air conditioner constructed using an absorption heat pump according to the present invention. The air conditioner shown in FIG. 2 differs from the air conditioner shown in FIG. 2 in that a three-way valve 66, which connects the outlet side and the inlet side of the expansion valve 34, flows in the liquid refrigerant pipe 67 on the downstream side of the expansion valve 34. One side of the three-way valve 66 is interposed by the liquid refrigerant pipe 67 to the upper end (entrance side) of the heat exchanger 48, and the other side of the three-way valve 66 is connected to the absorption unit 36 by the liquid refrigerant pipe 68. Are respectively connected to the solution spraying device 51 installed on the top of the head. Further, an outside air temperature sensor (not shown) is provided, and an actuator (not shown) or an evaporator outlet heat medium temperature that operates according to the output of the outside air temperature sensor or a signal output from the result calculated by the output of the sensor A sensor operates the three-way valve 66. The other structure is the same as that shown in FIG. 2, and therefore, the same reference numerals are given and the description thereof is omitted.

During the cooling operation and the normal heating operation (when the outside air temperature is above the preset lower limit temperature), the three-way valve 6
6 is operated at a position where the outlet side of the heat exchanger 45 communicates with the liquid refrigerant pipe 67, and an absorption refrigeration cycle is constituted.

During the heating operation, if the outside air temperature measured by the outside air temperature sensor becomes lower than the preset lower limit temperature,
The three-way valve 66 is switched by the actuator to a position where the outlet side of the heat exchanger 45 communicates with the liquid refrigerant pipe 68. By this switching, the liquid refrigerant (ammonia liquid) is guided to the solution spraying device 51 instead of flowing into the heat exchanger 48 of the evaporator 35. The liquid refrigerant guided to the solution spraying device 51 is mixed therewith via the pressure reducing valve 57 with the weak solution introduced into the solution spraying device 51, dropped on the outer surface of the absorption heat recovery heat exchange section 52, and then absorbed heat radiation. It flows down along the outer surface of the portion 53. Dilution heat and sensible heat of the solution generated by mixing the weak solution and the liquid refrigerant are recovered by the strong solution flowing in the absorption heat recovery heat exchange section 52 and the heat medium flowing in the absorption heat radiating section 53. Since the liquid refrigerant does not flow into the heat exchanger 48 of the evaporator 35, the liquid refrigerant does not evaporate and therefore the heat medium in the heat exchanger 48 is not cooled. In this case, the heat pump effect disappears and the efficiency becomes equivalent to that of boiler operation, but the heat medium is not cooled below the planned outside temperature, so there is no fear of freezing of the heat medium, and heating operation Will continue without any problems.

At this time, the absorption unit container 36a
There is no inflow of refrigerant vapor and no heat of absorption is generated. When the outside air temperature is recovered to be equal to or higher than the lower limit temperature, the three-way valve 66 is operated again to guide the liquid refrigerant to the heat exchanger 48 of the evaporator 35 to evaporate it, and the space between the outdoor air heat exchanger 65 and the evaporator barrel side The circulating heat medium may be cooled. In order to avoid hunting of the three-way valve 66, the outside air temperature or the heat medium temperature (lower limit temperature) when operating the outlet side of the three-way valve 66 so as to communicate with the liquid refrigerant pipe 67 side, It is desirable to set the temperature slightly higher than the lower limit temperature when operating so as to communicate with the liquid refrigerant pipe 68 side.

In the above embodiment, the three-way valve 66 is used as the flow path switching means. However, if the refrigerant flowing from one inlet can be switched to at least one of the two outlets and guided, it is not necessarily a three-way valve. Need not be used. For example, a Y-shaped branch pipe may be provided, and a stop valve may be provided in each of the two branch pipes on the outlet side.

Further, the absorption unit 3 is passed through the flow path switching means.
From the viewpoint of heat recovery, it is desirable to configure the piping system so that the liquid refrigerant supplied to 6 is mixed with the weak solution in the solution spraying device 51 installed in the absorption unit 36. It may be mixed with a weak solution on the outer surface of the part 52.

[0029]

According to the present invention, when the outside air temperature falls below a preset temperature during the heating operation, the refrigerant is not evaporated in the evaporator, so that the cooling of the heat medium in the evaporator is stopped. The heat pump will not be stopped due to the freezing of the heat medium.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of an air conditioner to which the present invention is applied.

FIG. 2 is a system diagram of an air conditioner showing an example of a conventional technique.

[Explanation of symbols]

31 Regenerator Unit 31a Regenerator Unit Container 32 Condenser 34 Expansion Valve 35 Evaporator 36 Absorption Unit 36a Absorption Unit Container 37 Solution Circulation Pump 39 Regeneration Heater 40 Weak Solution Heat Exchanger 41 Fractionator 42 Splitter 43a Strong Solution 45 Heat exchanger 48 Heat exchanger 51 Solution spraying device 52 Absorption heat recovery heat exchange part 53 Absorption heat radiation part 57 Pressure reducing valve 61 Heat medium circulation pump 62 Heat medium circulation pump 63 Cooling / heating switching device 64 Indoor air heat exchanger 65 Outdoor Air heat exchanger 66 Three-way valve 67 Liquid refrigerant pipe 68 Liquid refrigerant pipe

Claims (5)

[Claims] 1. A regenerator unit 31 for separating a strong solution into a refrigerant vapor and a weak solution, a condenser 32 for condensing and liquefying the refrigerant vapor separated by the regenerator unit 31, and a condenser 32.
An evaporator 35 that introduces the liquid refrigerant generated in step 3 through an expansion valve 34 and evaporates by heat exchange with a heat medium, and the evaporator 3
5. An absorption heat pump including an absorption unit 36 for absorbing the refrigerant vapor evaporated in step 5 into the weak solution, and a flow path switching means having at least two outlet sides in the liquid refrigerant pipe 67 downstream of the expansion valve 34. 66, an absorption heat pump characterized in that one outlet of the flow path switching means is connected to the evaporator 35 and the other outlet is connected to the upper part of the absorption unit 36. 2. The absorption heat pump according to claim 1, wherein the flow path switching means is a three-way valve 66. 3. The flow path switching means includes a Y-shaped branch pipe having one end connected to the expansion valve outlet side, and an on-off valve connected to the other two ends of the Y-shaped branch pipe. The absorption heat pump according to claim 1, wherein the absorption heat pump is configured as follows. 4. The absorption unit 36 includes a solution spraying device 51 disposed above the absorption heat recovery heat exchange part 52, and the liquid refrigerant introduced through the flow path switching means is guided to the solution spraying device 51. The absorption heat pump according to any one of claims 1 to 3, wherein the absorption heat pump is configured so as to be mixed with the weak solution. 5. A regenerator unit 31 for separating a strong solution into a refrigerant vapor and a weak solution, a condenser 32 for condensing and liquefying the refrigerant vapor separated by the regenerator unit, and a liquid refrigerant produced by the condenser 32. Is introduced through an expansion valve 34 and evaporates by heat exchange with a heat medium, and an absorption unit 36 that absorbs the refrigerant vapor evaporated in the evaporator 35 into the weak solution. In the method of operating the type heat pump, during heating operation, the outside air temperature is measured, and when the measured outside air temperature falls below a preset lower limit temperature,
A method of operating an absorption heat pump, characterized in that the refrigerant that has passed through the expansion valve 34 is guided to an absorption unit 36 and mixed with a weak solution in the absorption unit 36.