JP2003336924A - Defrosting device of absorption refrigerating machine and absorption heat pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a coefficient of performance from being deteriorated by preventing a heat exchange from being obstructed by frosting. <P>SOLUTION: In a defrosting operation, an expansion valve 21 for defrosting is installed between an evaporator 6 and an absorber 5, and a refrigerant bypass route 26 is installed between a generator 8 and the evaporator 6. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defroster for an absorption refrigerator / heat pump.

[0002]

2. Description of the Related Art Absorption refrigerators are generally used for district heating and cooling. The absorption chiller is a type of cogeneration and is driven by waste heat of a gas turbine or the like, so that the energy efficiency of the entire system is relatively high. The absorption refrigerator can also be used as a heat pump, and for district cooling and heating, heat absorbed from sewage, river water, etc. is used for heating and the like.

FIG. 2 shows the structure of a conventional absorption refrigerating machine / absorption heat pump. Reference numeral 1 denotes a gas turbine generator, which is constituted by connecting a generator 3 to a gas turbine 2. The gas turbine 2 compresses gas (air) with the compressor 2a, heats this gas with the combustor 2b, supplies the produced | generated high temperature high pressure gas to the turbine 2c, and rotates the turbine 2c. The exhaust gas of the gas turbine 2 is exhausted via the heat exchanger 4.

On the other hand, the absorber 5 absorbs the low-temperature and low-pressure refrigerant vapor discharged from the evaporator 6 by the absorbent, and produces heat during the absorption, so the hot water 1 is obtained by utilizing this heat. The absorbent whose concentration of the refrigerant has increased due to absorption is sent to the generator 8 by the pump 7, and is heated by the driving heat source such as steam in the generator 8 to generate the refrigerant vapor, which is output to the condenser 9. Go. The absorbent whose refrigerant concentration has become thin in the generator 8 heats the low-temperature absorbent from the absorber 5 in the heat exchanger 10, and then is decompressed by the pressure reducing valve 11 and returned to the absorber 5.

In the condenser 9, the refrigerant vapor is radiatively condensed and the hot water 2 is obtained. The liquid refrigerant is decompressed by the expansion valve 12 and fed into the evaporator 6. In the evaporator 6, the low temperature brine obtained by absorbing heat from the surroundings and evaporating, is carried by the pump 13 to the outdoor unit 14 and blown by the fan 15. The low-temperature low-pressure refrigerant discharged from the evaporator 6 is absorbed by the absorber 5. Further, steam or the like as a driving heat source is circulated by the pump 16, heated in the heat exchanger 4 by the exhaust gas of the turbine 2c, and returned to the generator 8 again.

[0006]

By the way, FIG. 3 shows a refrigeration cycle of an absorption refrigerator / absorption heat pump, and the solid line in the figure is its Ts diagram. The double-lined arrow is T-
The temperatures of the driving heat source, hot water 1, hot water 2, and air corresponding to the s diagram. When the temperature is around 0 ° C to 5 ° C, the evaporator 6 absorbs heat from the atmosphere by operating the heat pump.
In the heat exchanger of No. 4, the surface temperature reaches below the freezing point and frost is easily generated. When the surface of the heat exchanger is covered with frost, heat exchange is hindered and the coefficient of operation of the heat pump operation deteriorates. or,
When operating as a refrigerator, the same phenomenon occurs in a heat exchanger such as in a freezer.

The present invention has been made in order to solve the above-mentioned problems, and it is an absorption refrigerating machine / absorption heat pump which can prevent the heat exchange from being hindered by frost and can prevent the deterioration of the coefficient of operation. The purpose is to obtain a defroster.

[0008]

A defroster for an absorption refrigerating machine / absorption heat pump according to claim 1 of the present invention is an absorber that absorbs a refrigerant discharged from an evaporator with an absorbent, and an absorption from the absorber. An absorption refrigeration system that includes a generator that heats the agent with a driving heat source to generate refrigerant vapor, a condenser that condenses the refrigerant vapor from the generator, and an evaporator that evaporates the refrigerant from the condenser In a machine / absorption heat pump, the evaporator is operated as a condenser during defrosting operation.

In the defroster for an absorption refrigerating machine / absorption heat pump according to a second aspect, a defrosting expansion valve is provided between the evaporator and the absorber during the defrosting operation, and a refrigerant is provided between the generator and the evaporator. The bypass route is provided. In order to avoid an adverse effect on the heat cycle, a closing valve is provided at the refrigerant inlet and the refrigerant outlet of the condenser, and at least one closing valve is closed.

The defroster for an absorption refrigerating machine / absorption heat pump according to the third aspect is provided with a defrosting valve for preventing backflow between the expansion valve for defrosting and the absorber during defrosting operation.

The defroster for an absorption refrigerating machine / absorption heat pump according to a fourth aspect is provided with a defrosting evaporator between the defrosting expansion valve or defrosting valve and the absorber during defrosting operation. is there. During defrosting operation, the absorber is prevented from freezing and hot water can be supplied to the absorber. When the defrosting evaporator is used during normal operation, the amount of heat obtained by operating the heat pump increases.

The defroster for an absorption refrigerating machine / absorption heat pump according to a fifth aspect uses, as the heat source of the defrosting evaporator, any of the residual heat of the driving heat source of the generator, air and cooling water. .

In a defroster for an absorption refrigerating machine / absorption heat pump according to a sixth aspect, during normal operation, the defrosting evaporator is connected between the evaporator and the absorber, and as a driving heat source for the generator, The exhaust of a regeneration cycle gas turbine that recovers heat from the exhaust to compressed air is used. When the exhaust of the regeneration cycle gas turbine is used as the driving heat source, the amount of heat obtained during the operation of the heat pump is increased by combining with the evaporator for defrosting, and hot water during defrosting operation is also obtained.
Also, no special heat source is required.

In the defroster for an absorption refrigerating machine / absorption heat pump according to a seventh aspect, the defrosting evaporator is provided between the evaporator and the absorber during normal operation, and the defrosting evaporator is provided as a generator. A part or all of the driving heat source to be supplied is supplied.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows the configuration of an absorption refrigerator / heat pump equipped with a defroster according to Embodiment 1 of the present invention. In a gas turbine generator 1, a gas turbine 2 compresses gas with a compressor 2a, Is heated by exchanging heat with the exhaust gas of the turbine 2c in the heat exchanger 4, and
The gas is heated by the combustor 2b, becomes high-temperature and high-pressure gas and is supplied to the turbine 2c, and the turbine 2c rotates. Therefore,
The gas turbine 2 is a regeneration cycle gas turbine that recovers heat from exhaust gas to compressed air.

After heat exchange, the exhaust gas of the turbine 2c is supplied to the defrosting evaporator 19 via the exhaust valve 17 or is supplied to the generator 8 as a driving heat source via the exhaust valve 18 for post-defrosting. It is supplied to the evaporator 19 and discharged to the chimney.

On the other hand, the refrigerant discharged from the evaporator 6 is shut off by the shutoff valve 2.
0, or after being sent to the defrosting evaporator 19 via the defrosting expansion valve 21 and the defrosting valve 22, it is sent to the absorber 5. From the absorber 5, as in the conventional case, the absorbent is sent to the generator 8 via the heat exchanger 10 by the pump 7, and the refrigerant vapor from the generator 8 is sent to the condenser 9 via the shutoff valve 23. At the same time, it is supplied to the evaporator 6 via the bypass valve 24 provided in the bypass path 26. Further, the liquid refrigerant from the condenser 9 is sent to the evaporator 6 via the shutoff valve 25 and the expansion valve 12.

In the above structure, when the shutoff valve 20 is opened, the defrost valve 22 is closed, the exhaust valve 18 is opened and the exhaust valve 17 is closed, and the shutoff valves 23 and 25 are opened and the bypass valve 24 is closed. The operation is performed, the absorbent that has absorbed the refrigerant is sent to the generator 8, and is heated by using the exhaust gas of the regeneration cycle gas turbine 2 as a driving heat source. Therefore, the refrigerant vapor is generated from the generator 8, and this refrigerant vapor is passed through the shutoff valve 23 to the condenser 9
And is condensed into a liquid refrigerant, and this liquid refrigerant is sent to the evaporator 6 through the shutoff valve 25 and the expansion valve 12,
Evaporate. The low-temperature low-pressure refrigerant is sent to the defrosting evaporator 19 via the shutoff valve 20, heated by the exhaust gas of the regeneration cycle gas turbine 2 that has passed through the generator 8, and then absorbed by the absorber 5.

When the surface of the heat exchanger of the outdoor unit 14 is covered with frost, the bypass valve 24 and the defrost valve 22 are opened,
When the shutoff valves 20, 23, 25 are closed, the normal operation is switched to the defrosting operation, and the high-temperature and high-pressure refrigerant discharged from the generator 8 enters the evaporator 6 through the bypass path 26 and the defrosting expansion valve 21. By providing, the pressure in the evaporator 6 rises, and the evaporator 6 operates as a condenser. For example, when ammonia is used as the refrigerant and water is used as the absorbent, the temperature of the evaporator 6 reaches a maximum of 50 ° C. Therefore, the temperature of the brine discharged from the evaporator 6 to the outdoor unit 14 rises, the temperature of the heat exchanger of the outdoor unit 14 also rises, and the defrosting is performed. During such a defrosting operation, the fan 15
Is stopped.

Further, in the gas turbine generator 1, heat is recovered from the exhaust gas of the turbine 2c to the compressed air, which is a regenerative cycle gas turbine. Since the regeneration cycle gas turbine has a low exhaust temperature, ΔT1 in FIG. 3 is small and is not suitable as a drive heat source for the generator 8. However, the defrosting evaporator 21 is used during normal operation as well. ,
The amount of heat obtained during the heat pump operation can be increased, and since ΔT2 is large relative to ΔT1, hot water 1 can be supplied during the defrosting operation.

Although the brine is circulated between the evaporator 6 and the outdoor unit 14, the refrigerant may be directly supplied to the outdoor unit 14. When operating as a refrigerator instead of the heat pump operation, the heat exchanger of the outdoor unit 14 becomes the heat exchanger in the freezer. The defrost valve 22 is provided in order to avoid inconvenience such as freezing of the defrost expansion valve 21 due to the reverse flow of the absorbent, but it may be omitted if it is not necessary in the structure. In addition, by providing the shutoff valves 23 and 25, it is possible to avoid the refrigerant from condensing and stagnating in the condenser 9 during defrosting and disturbing the heat cycle, but the shutoff valves 23 and 25 are not necessary. However, it may be omitted.

As described above, by operating the evaporator 6 as a condenser, it is possible to defrost the evaporator 6, prevent heat exchange from being hindered by frost, and prevent deterioration of the coefficient of operation. it can.

Further, as described above, when the evaporator 6 is operated as a condenser, the refrigerant condensed in the evaporator 6 flows into the absorber 5 through the defrosting expansion valve 21, so that the absorbing liquid is generated. It may freeze. Therefore, in order to avoid this, the defrosting evaporator 19 is provided to heat and evaporate the refrigerant. As the heat source of the defrosting evaporator 19, any air or the like may be used, but in the first embodiment, the generator 8 is used.
The residual heat of the exhaust gas of the gas turbine 2 which is the driving heat source of the above is used. As shown by ΔT2 in FIG. 3, the residual heat of the driving heat source exceeds the temperature of the generator 8. For easy understanding, the horizontal axes of the driving heat source, air, warm water 1 and warm water 2 in FIG. 3 are indicated by the specific entropy s of the corresponding refrigerant or absorbing liquid. By providing the defrosting evaporator 19 in this way, the hot water 1 can be supplied in some cases even during the defrosting operation. Further, the defrosting evaporator 19 is also used during the normal operation, whereby the residual heat ΔT2 of the driving heat source can be recovered to below the freezing point, and the amount of heat obtained during the operation of the heat pump can be increased. In that case, defrosting of the defrosting evaporator 19 itself is necessary, and the defrosting is performed by supplying heat to the defrosting evaporator 19 while reducing or stopping the capacity of the absorption refrigerator / absorption heat pump. be able to. Specifically, the exhaust valve 18 is throttled or closed, and the exhaust valve 17 is slightly opened or fully opened. This reduces or shuts down the absorption heat pump. As a result, the defrosting evaporator 19 is no longer cooled and frost is removed by the driving heat source.

Embodiment 2 In Embodiment 2, when operating as an absorption refrigerator, the cooling water of the absorber 5 and the condenser 9 supplied from a cooling tower or the like is used as the heat source of the defrosting evaporator 19. it can. As a result, it is not necessary to provide a heat source during defrosting. Many radiators such as cooling towers can also absorb heat.

Embodiment 3 When operating as an absorption refrigerator, depending on conditions, defrosting operation is possible without the defrosting evaporator 19. This is because the cooling water supplied from the cooling tower or the like supplies heat to the absorber 5.

[0026]

As described above, according to claims 1 and 2 of the present invention, during the defrosting operation, the expansion valve for defrosting is provided between the evaporator and the absorber, and the generator and the evaporator are connected. Since the refrigerant bypass path is provided therebetween, the evaporator operates as a condenser, the temperature of the evaporator rises, and defrosting is performed. Therefore, the heat exchange in the evaporator is smoothly performed and the coefficient of operation is improved.

In the third aspect, the defrosting valve is provided between the defrosting expansion valve and the absorber during defrosting operation to prevent backflow of the absorbent and to prevent freezing of the defrosting expansion valve. can do.

According to the present invention, the defrosting evaporator is provided between the defrosting expansion valve or the defrosting valve and the absorber during the defrosting operation to prevent the absorber from freezing and during the defrosting operation. Also in this case, hot water can be supplied to the absorber.

In the fifth aspect, the residual heat of the driving heat source of the generator, air, and cooling water are used as the heat source of the defrosting evaporator, so that no special heat source is required.

In the sixth aspect, the defrosting evaporator is connected between the evaporator and the absorber during normal operation, and
The exhaust gas of the regeneration cycle gas turbine is used as the drive heat source of the generator, and the amount of heat during operation of the heat pump can be increased.

According to a seventh aspect of the present invention, during normal operation, the defrosting evaporator is provided between the evaporator and the absorber, and a part or all of the driving heat source to be supplied to the generator is supplied to the defrosting evaporator. The defrosting evaporator is no longer cooled due to the reduced capacity of the absorption heat pump, and the defrosting evaporator is heated by the driving heat source to remove frost from the defrosting evaporator. be able to.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an absorption refrigerator / absorption heat pump according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional absorption refrigerator / absorption heat pump.

FIG. 3 is a refrigeration cycle diagram of an absorption refrigerator / absorption heat pump.

[Explanation of symbols]

1 ... Gas turbine generator 2 ... Gas turbine 5 ... Absorber 6 ... Evaporator 8 ... Generator 9 ... Condenser 14 ... Outdoor unit 17, 18 ... Exhaust valve 19 ... Evaporator for defrosting 20, 23, 25 ... Closed valve 21 ... Defrosting expansion valve 22 ... Defrost valve 24 ... Bypass valve 26 ... Bypass route

Claims (7)

[Claims] 1. An absorber that absorbs refrigerant discharged from an evaporator with an absorbent, a generator that heats the absorbent from the absorber with a driving heat source to generate refrigerant vapor, and a refrigerant vapor from the generator. An absorption refrigerating machine / absorption heat pump that includes a condenser for condensing and an evaporator for evaporating the refrigerant from the condenser, and in the absorption chiller / absorption heat pump that normally operates, the absorption characterized by operating the evaporator as a condenser during defrosting operation. Defroster for refrigerators and absorption heat pumps. 2. A defrosting expansion valve is provided between the evaporator and the absorber during defrosting operation, and a refrigerant bypass path is provided between the generator and the evaporator.
Defrosting device for the absorption refrigerator / heat pump described. 3. A defroster for an absorption refrigerating machine / absorption heat pump according to claim 2, wherein a defrosting valve for preventing backflow is provided between the expansion valve for defrosting and the absorber during defrosting operation. . 4. The absorption refrigerator / absorber according to claim 2, wherein a defrosting evaporator is provided between the defrosting expansion valve or defrosting valve and the absorber during the defrosting operation. Defroster for heat pump. 5. The frost for an absorption refrigerating machine / absorption heat pump according to claim 4, wherein any one of residual heat of a driving heat source of a generator, air and cooling water is used as a heat source of the defrosting evaporator. Device. 6. An exhaust of a regenerative cycle gas turbine, wherein a defrosting evaporator is connected between the evaporator and the absorber during normal operation, and heat is recovered from the exhaust into compressed air as a driving heat source of the generator. The defroster for an absorption refrigerator / absorption heat pump according to claim 4 or 5, characterized in that. 7. The defrosting evaporator is connected between the evaporator and the absorber during normal operation so that the defrosting evaporator is supplied with a part or all of the driving heat source to be supplied to the generator. The defroster for an absorption refrigerating machine / absorption heat pump according to any one of claims 4-6.