JP2007010288A - Cooling and heating capacity enhancement method of existing heat pump type air conditioner, thermal storage unit device and heat pump type air conditioner using the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold storage unit device capable of enhancing cooling and heating capacity which can be mounted on an existing building-multi type air conditioning facility and a heat pump type air conditioner mounted with the cold storage unit device. <P>SOLUTION: The method is to enhance cooling and heating capacity of the existing heat pump type air conditioner structured by connecting an outdoor unit and an indoor unit with two existing refrigerant pipes. The thermal storage unit device 3 is equipped with a thermal storage tank 23 for storing thermal storage medium, the thermal storage medium 25, stored in the thermal storage tank 23, having a melting point Tm which is higher than an evaporation temperature Te of the refrigerant and lower than a condensation temperature Tc in the heat pump type air conditioner which has been already installed and a heat exchanger 27 for conducting heat exchange between the thermal storage medium and refrigerant of a refrigerating cycle. The thermal storage unit device 3 is installed between the outdoor unit 1 and the indoor unit 5 in the existing heat pump type air conditioner. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for increasing the cooling / heating capacity of an existing heat pump type air conditioner, a heat storage unit device that is attached to an existing heat pump type air conditioner to enhance the cooling / heating capacity of the heat pump type air conditioner, and a heat pump type air conditioner using the apparatus. is there.

The following proposals have been made for the purpose of carrying out energy-saving operation with high running efficiency and reduced running costs and peak cuts in summer by attaching a cold storage unit with a built-in heat storage tank to the refrigeration cycle.
It has a refrigeration cycle consisting of a compressor, a four-way switching valve, an indoor heat exchanger, a pressure reducing mechanism, an outdoor heat exchanger, and the like, and collects the energy stored in the cold storage heat operation and the cold storage heat operation in the refrigeration cycle. A cold storage heat unit is provided by a heat storage tank that performs a cold storage heat recovery operation and first, second, third, and fourth solenoid valves that control each operation, and the cold storage heat unit can be attached to and detached from the refrigeration cycle. A regenerative air conditioner to be attached (see Patent Document 1).
JP 58-19665 (Claims, Fig. 2)

The regenerative air conditioner described in Patent Document 1 includes a pressure reducing mechanism on the outdoor unit side. Since the refrigerant is a gas refrigerant on the downstream side of the decompression mechanism and the volume flow rate is significantly increased as compared with the liquid refrigerant, the pressure loss when passing through the pipe increases. Therefore, if the pressure reducing mechanism is provided on the outdoor unit side, the performance deteriorates when the distance between the outdoor unit and the indoor unit is long. Therefore, the air conditioner targeted by Patent Document 1 is installed close to the outdoor unit and the indoor unit. It is thought that it is an air conditioner.
Therefore, the object is different from what is called a building multi-type air conditioner in which an outdoor unit and a plurality of indoor units are connected by a long refrigerant pipe.
In addition, since there is no decompression mechanism in the cold storage heat unit, the heating operation using the heat storage and the defrosting operation cannot be performed.

Moreover, there is no description about the heat storage material stored in the heat storage tank of Patent Document 1. If it is a case of storing heat with ice, cooling is required to below the freezing point of ice. However, the evaporating temperature of the refrigerant used in a general existing heat pump air conditioner is 5 to 10 ° C., and ice cannot be made by lowering the evaporating temperature to 0 ° C. or lower. Therefore, an ice-making operation cannot be performed with a general air conditioning heat pump, or the efficiency of the heat pump is very low even if it is possible. When ice is used as a heat storage material, in order to efficiently store cold (ice making), a dedicated heat source device specially designed so as to be able to cope with an evaporation temperature of 0 ° C. or lower is required.
Therefore, in the thing of patent document 1, it is difficult to add the cold storage heat unit as it is to the existing heat pump type air conditioner and to enhance the cooling / heating capacity by ice heat storage.
Also, assuming that the ice storage tank will be retrofitted in the future, it is possible to make the specification of the heat pump compatible with an evaporation temperature of 0 ° C. or less, but during normal cooling operation that does not use the cold heat of the cold storage heat unit ( The refrigerant evaporating temperature 5 to 10 ° C. is less efficient than a heat pump designed for an evaporating temperature 5 to 10 ° C.

The present invention has been made to solve such a problem, and can be attached to an existing building multi-air-conditioning equipment, and a heat storage unit device capable of improving the cooling and heating capacity, and a heat pump type attached with the heat storage unit device. The purpose is to obtain an air conditioner.
Another object of the present invention is to obtain a method for enhancing the cooling / heating capacity of an existing heat pump air conditioner.

(1) The method for enhancing the cooling / heating capacity of a heat pump air conditioner according to the present invention is a method for enhancing the cooling / heating capacity of an existing heat pump air conditioner in which an outdoor unit and an indoor unit are connected by two refrigerant pipes. A heat storage tank that stores the heat storage material, a heat storage material that is stored in the heat storage tank and has a melting point Tm that is higher than the evaporation temperature Te of the refrigerant and lower than the condensation temperature Tc in the existing heat pump air conditioner, and the heat storage material and the heat storage material A heat storage unit device having a heat storage heat exchanger for exchanging heat with the refrigerant is installed between the outdoor unit and the indoor unit in the existing heat pump type air conditioner, and cools the heat storage material in the heat storage tank during the cooling off-peak. The temperature at which heat is stored in the heat storage material in the heat storage tank during off-peak hours of heating is performed. It performs thermal storage operation, and is characterized in performing the heat storage utilization heating operation of the heating operation using the heat that is accumulated in the heat storage material at peak.

(2) Moreover, the heat storage unit apparatus which concerns on this invention is a heat storage unit apparatus attached to the existing heat pump type air conditioner which connects an outdoor unit and an indoor unit with two refrigerant | coolant piping of liquid refrigerant piping and gas refrigerant piping. A second pipe that can be inserted and connected in the middle of the liquid refrigerant pipe and has first and second on-off valves; and a second pipe that can be inserted and connected in the middle of the gas refrigerant pipe and has a third on-off valve. Piping, a heat storage tank that stores the heat storage material, a heat storage material that is stored in the heat storage tank and has a melting point Tm that is higher than the evaporation temperature Te of the refrigerant and lower than the condensation temperature Tc in the existing heat pump air conditioner, and the heat storage material And a heat storage heat exchanger for exchanging heat with the refrigerant, one end of the heat storage heat exchanger being connected to an expansion valve and a fourth on-off valve, the first and second on-off valves in the first pipe Between the pipes and the heat storage heat exchanger An end side is connected via a fifth on-off valve to a position closer to the outdoor unit side than the third on-off valve in the second pipe, and the other end side of the heat storage heat exchanger is connected via a sixth on-off valve. The pipe is connected to a position closer to the indoor unit than the first and second on-off valve installation parts in the first pipe.

(3) Moreover, in the thing as described in said (2), the other end side of the heat exchanger for heat storage is an outdoor unit side rather than the 1st, 2 on-off valve installation part in said 1st piping via a 7th on-off valve. It is characterized in that a pipe connection is made at a position.

(4) Further, in the above (2) or (3), the heat storage material has a melting point Tm of Te <Tm <Te + 10 ° C.

(5) Moreover, the heat pump type air conditioner which concerns on this invention attached the heat storage unit apparatus in any one of said (2)-(4) to the heat pump type air conditioner which has an outdoor unit and an indoor unit. It is what.

  In the present invention, by using a heat storage material having a melting point Tm higher than the evaporation temperature Te of the refrigerant and lower than the condensation temperature Tc in the existing heat pump type air conditioner, two heat storage unit devices are provided for the existing heat pump type air conditioner. It is possible to enhance the cooling capacity by using the existing outdoor unit (heat source device) as it is simply by inserting it in the middle of the refrigerant piping of the book.

FIG. 1 is an explanatory view illustrating the configuration of a heat pump air conditioner incorporating a heat storage unit device according to an embodiment of the present invention. The heat pump type air conditioner of this example is the one in which the outdoor unit 1 and the indoor unit 5 are connected by two refrigerant pipes as an existing heat pump type air conditioner, and the heat storage unit device 3 is newly incorporated later. Yes, and includes an outdoor unit 1, a heat storage unit device 3, and a plurality of indoor units 5.
The outdoor unit 1 and the heat storage unit device 3 are connected by two refrigerant pipes 7 and 9, and the heat storage unit device 3 and the indoor unit 5 are similarly connected by two refrigerant pipes 11 and 13. In the existing heat pump air conditioner, the refrigerant pipe 7 and the refrigerant pipe 11 are liquid refrigerant pipes through which liquid refrigerant mainly flows, and the refrigerant pipe 9 and the refrigerant pipe 13 are gas refrigerant pipes through which mainly gas refrigerant flows.

  The outdoor unit 1 includes a compressor 15 that boosts the gas refrigerant to a predetermined pressure, an outdoor heat exchanger 17 that performs heat exchange between the refrigerant and the outside air, a four-way valve 19 that switches a refrigerant flow according to an operation mode, an expansion A valve 21 is provided. The four connection ports of the four-way valve 19 are connected to the discharge side and suction side of the compressor 15, one end side of the outdoor heat exchanger 17, and the refrigerant pipe 9 via pipes, respectively. The side opposite to the side connected to the four-way valve 19 in the outdoor heat exchanger 17 is connected to the refrigerant pipe 7 via the expansion valve 21.

The heat storage unit device 3 includes a heat storage tank 23 that stores the heat storage material 25, and a heat storage heat exchanger 27 that exchanges heat between the heat storage material 25 in the heat storage tank and the refrigerant.
As the heat storage material 25, a material having a melting point Tm higher than the refrigerant evaporation temperature Te and lower than the condensation temperature Tc in the existing heat pump air conditioner is used. The evaporation temperature Te and the condensation temperature Tc refer to the design evaporation temperature and the design condensation temperature of the existing heat pump air conditioner.
By using a heat storage material with a melting point Tm in this range, the heat storage material is changed from a liquid to a solid while maintaining a highly efficient operation state using the operation conditions at the evaporation temperature and condensation temperature of the existing heat pump air conditioner as they are. A large amount of heat can be stored and stored using the latent heat of solidification and melting at the time of phase change.
Thus, by using the heat storage material having the melting point Tm in this range, the heat storage unit device 3 can be directly attached to the existing heat pump air conditioner to enhance the cooling / heating capacity.
The melting point Tm of the heat storage material is more preferably set to Te <Tm <Te + 10 ° C. (<Tc). This is because when Tm is lower than Te + 10 ° C., the degree of supercooling of the refrigerant can be sufficiently obtained during the cold storage use operation described later, and the cold stored cold energy can be used effectively.
Since the evaporating temperature of the refrigerant in the existing heat pump type air conditioner is often about 5 to 10 ° C., the melting point Tm of the heat storage material is more preferably 5 to 20 ° C.
Specific examples of such a heat storage material include a hydrate heat storage material, tetra-n-butylammonium bromide hydrate having a melting point of 12 ° C, and tri-n-butyl-n-pentylammonium bromide hydrate having a melting point of 9 ° C. And tetrabutyl ammonium nitrate hydrate having a melting point of 6.5 ° C.
In the case of paraffin, tetradecane having a melting point of 5 to 6 ° C. is exemplified.

Returning to FIG. 1 again, the apparatus configuration will be described.
A pipe 29 having one end connected to the refrigerant pipe 7 and the other end connected to the refrigerant pipe 11 (corresponding to the first pipe of the present invention), a pipe having one end connected to the refrigerant pipe 9 and the other end connected to the refrigerant pipe 13 31 (corresponding to the second pipe of the present invention). The pipe 29 is provided with an on-off valve 33 (corresponding to the first on-off valve of the present invention) and an on-off valve 35 (corresponding to the second on-off valve of the present invention) in order from the side closer to the refrigerant pipe 7. The pipe 31 is provided with an on-off valve 37 (corresponding to the third on-off valve of the present invention).

One end side of the heat storage heat exchanger 27 is connected between the on-off valves 33 and 35 in the pipe 29 via the pipe 39. The piping 39 is provided with an expansion valve 41, an accumulator 43, and an on-off valve 45 (corresponding to the fourth on-off valve of the present invention) in order from the side closer to the heat storage heat exchanger 27.
The other end of the heat storage heat exchanger 27 is connected to the pipe 31 and the pipe 29 via three pipes 47, 49, 51. That is, the pipe 47 is connected to a position closer to the refrigerant pipe 9 than the opening / closing valve 37 in the pipe 31, and is connected to the position closer to the refrigerant pipe 7 than the opening / closing valve 33 in the pipe 29 via the pipe 49. Is connected to the side closer to the refrigerant pipe 11 than the on-off valve 35 in the pipe 29. The pipe 47 has an on-off valve 53 (corresponding to the fifth on-off valve of the present invention), the pipe 49 has an on-off valve 55 (corresponding to the seventh on-off valve of the present invention), and the pipe 51 has an on-off valve 57 (corresponding to the fifth on-off valve). Equivalent to the sixth on-off valve of the present invention).

The indoor unit 5 is provided with an indoor heat exchanger 59 that performs heat exchange between the indoor air and the refrigerant. One end of the indoor heat exchanger 59 is connected to the refrigerant pipe 11 and the other end is connected to the refrigerant pipe 13 via the pipe. An expansion valve 61 is provided in a path connecting the indoor heat exchanger 59 and the refrigerant pipe 11.
In FIG. 1, the outdoor unit 1 and the indoor unit 5 show a representative configuration in which only main components are illustrated, and an accumulator, a control valve, and the like are connected as necessary, or a plurality of components are installed. May be. That is, the equipment configuration of the outdoor unit and the indoor unit is not limited as long as the outdoor unit and the indoor unit are connected to each other by two refrigerant pipes.

  In the heat pump type air conditioner configured as described above, the normal cooling operation for performing the cooling operation without causing the heat storage unit device 3 to function, the cold storage operation for storing cold in the heat storage material 25 in the heat storage tank 23, and the heat storage material 25 Cold storage-use cooling operation in which cooling operation is performed using the stored cold energy, normal heating operation in which heating operation is performed without causing the heat storage unit device 3 to function, thermal heat storage operation in which heat is stored in the heat storage material 25 in the heat storage tank 23, heat storage material Each operation mode of the heat storage use heating operation which performs the heating operation using the heat stored in 25 is possible.

2-7 is explanatory drawing explaining the flow of the refrigerant | coolant in each of these operation modes, FIG. 2 is normal cooling operation, FIG. 3 is cold storage operation, FIG. 4 is cool storage utilization cooling operation, FIG. 5 is normal heating operation, FIG. 6 shows a heat storage operation, and FIG. 7 shows a heat storage utilization heating operation. 2-7, the piping through which the refrigerant passes is indicated by a solid line, and the piping through which the refrigerant does not pass is indicated by a broken line. Each open / close valve has an open state shown in white and a closed state shown in black.
FIG. 8 is a Mollier diagram in the cooling-related operation mode, and FIG. 9 is a Mollier diagram in the heating-related operation mode.
Hereinafter, each operation mode will be described with reference to FIGS.

(1) Normal cooling operation During normal cooling operation, as shown in FIG. 2, the on-off valves 33, 35, and 37 of the heat storage unit device 3 are opened, and the on-off valves 45, 53, 55, and 57 are closed. Therefore, the refrigerant only passes through the pipes 29 and 31 of the heat storage unit 3, and the heat storage function and the heat storage use function in the heat storage unit 3 do not function. Hereinafter, the operation of the entire heat pump air conditioner will be described.

The high-temperature and high-pressure refrigerant discharged from the compressor 15 is condensed by exchanging heat with the outside air in the outdoor heat exchanger 17 via the four-way valve 19. The temperature of the condensed liquid refrigerant is about 45 ° C. The liquid refrigerant passes through the fully-opened expansion valve 21 (the fully-opened expansion valve does not function as an expansion valve), passes through the refrigerant pipe 7, and is sent to the indoor unit 5 through the pipe 29 and the refrigerant pipe 11 of the heat storage unit device 3.
The high-pressure liquid refrigerant sent to the indoor unit 5 that is performing the cooling operation is depressurized by the expansion valve 61, evaporated by the indoor heat exchanger 59, and is cooled by exchanging heat with indoor air. The refrigerant vapor that has been cooled returns to the outdoor unit 1 through the refrigerant pipe 13, the pipe 31 of the heat storage unit device 3, and the refrigerant pipe 9, and is sucked into the compressor 15 through the four-way valve 19.
This refrigeration cycle constitutes an inverted trapezoidal refrigeration cycle A → B → C → D → A drawn by a thick solid line in FIG.

(2) Cold storage operation The cold storage operation is an operation mode that is performed at night in the summer, which is off-peak, and in this operation mode, as shown in FIG. 3, the on-off valves 33, 45, and 53 of the heat storage unit device 3 are opened. Thus, the on-off valves 35, 37, 55, and 57 are closed. Therefore, the refrigerant circulates between the outdoor unit 1 and the heat storage unit device 3 and does not go to the indoor unit 5 side. Specifically, the operation is as follows.
Until the refrigerant compressed by the compressor 15 is sent to the heat storage unit device 3 through the refrigerant pipe 7, it is the same as the normal cooling operation described above. The high-pressure liquid refrigerant sent to the heat storage unit device 3 passes through the on-off valves 33 and 45 and the accumulator 43, is depressurized by the expansion valve 41, evaporates in the heat storage heat exchanger 27, and exchanges heat with the heat storage material 25 to store the heat storage material. The cold energy is stored in 25. At this time, since the melting point of the heat storage material 25 is higher than the evaporation temperature of the refrigerant, it is stored as solidification latent heat. Therefore, a large amount of heat is stored cold.
The refrigerant vapor evaporated in the heat storage heat exchanger 27 passes through the opening / closing valve 53, passes through the refrigerant pipe 9, returns to the outdoor unit 1, and is sucked into the compressor 15 through the four-way valve 19.
The refrigeration cycle at this time is the refrigeration cycle A → B → C → D → A drawn by the thick solid line in FIG. 8 as in the normal cooling operation.

(3) Cooling and cooling use cooling operation Cooling and cooling use cooling operation is an operation mode performed during peak hours in the daytime, and in this operation mode, as shown in FIG. 4, on-off valves 33, 37, 45, 57 is opened, and the on-off valves 35, 53, and 55 are closed. Therefore, the refrigerant is sent from the outdoor unit 1 to the indoor unit 5 side via the heat storage heat exchanger 27 of the heat storage unit device 3, and returns to the outdoor unit 1 and circulates again. Specifically, the operation is as follows.
Until the refrigerant compressed by the compressor 15 is sent to the heat storage unit device 3 through the refrigerant pipe 7, it is the same as the normal cooling operation and the cold storage operation described above. The high-pressure liquid refrigerant (temperature is about 45 ° C.) sent to the heat storage unit device 3 passes through the on-off valves 33 and 45, the accumulator 43, and the fully-opened expansion valve 41 and flows to the heat storage heat exchanger 27. In the heat storage heat exchanger 27, the heat stored in the heat storage tank 23 is exchanged with the heat storage material 25, and the stored cold is taken out and the liquid refrigerant is brought into a supercooled state. In particular, since the heat storage material 25 of the present embodiment has a melting point higher than the refrigerant evaporation temperature Te and lower than Te + 10 ° C., the heat storage material 25 has a melting point Tm of about 20 ° C. at most. Cooling sufficiently from the inlet temperature (45 ° C.), the degree of supercooling of the liquid refrigerant can be increased.

The supercooled liquid refrigerant is sent to the indoor unit 5 through the pipe 51, the on-off valve 57 and the refrigerant pipe 11. The supercooled high-pressure liquid refrigerant sent to the indoor unit 5 performing the cooling operation is depressurized by the expansion valve 61, evaporated by the indoor heat exchanger 59, and is cooled by exchanging heat with room air. . At this time, since the liquid refrigerant is supercooled, the cooling capacity per unit refrigerant amount can be increased. Since the cooling capacity per unit refrigerant volume can be increased, if the required cooling capacity (cooling demand) is the same, the amount of refrigerant circulation, that is, the number of revolutions of the compressor can be reduced accordingly. The amount can be reduced. Alternatively, the cooling capacity can be increased without increasing the power consumption by setting the same rotational speed of the compressor as in the normal operation.
The refrigerant vapor that has been cooled returns to the outdoor unit 1 through the refrigerant pipe 13, the pipe 31 of the heat storage unit device 3, and the refrigerant pipe 9, and is sucked into the compressor 15 through the four-way valve 19.
This refrigeration cycle constitutes a refrigeration cycle of A → B → c → d → A drawn by a thick solid line and a broken line in FIG. C → c in the refrigeration cycle indicates the degree of supercooling. In the refrigeration cycle, D → A (P1) indicates the cooling capacity during normal cooling operation, and d → A (P2) indicates the cooling capacity during cooling operation using the cold storage. From D → A (P1) Since the specific enthalpy difference of d → A (P2) is large, it can be seen that the cooling capacity is enhanced.

(4) Normal heating operation In the normal heating operation, the four-way valve 19 is switched so that the discharge side of the compressor 15 communicates with the refrigerant pipe 9. Moreover, in the heat storage unit apparatus 3, as shown in FIG. 5, the on-off valves 33, 35, and 37 are opened, and the on-off valves 45, 53, 55, and 57 are closed. In this way, the refrigerant only passes through the pipes 29 and 31 of the heat storage unit 3 as in the normal cooling operation, and the heat storage function and the heat storage use function in the heat storage unit 3 do not function.
The operation of the heat pump air conditioner is as follows.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 15 passes through the four-way valve 19, passes through the refrigerant pipe 9, the pipe 31 of the heat storage unit device 3, the refrigerant pipe 13, and the indoor unit side heat exchanger 59 of the indoor unit 5. Sent to. In the indoor heat exchanger 59, the indoor air is heated and heated by exchanging heat with the indoor air, and the refrigerant is cooled and condensed. The liquid refrigerant that has exited the indoor heat exchanger 59 passes through the fully opened expansion valve 61, and is sent to the outdoor unit 1 through the refrigerant pipe 11, the pipe 29 of the heat storage unit device 3, and the refrigerant pipe 7. The high-pressure liquid refrigerant sent to the outdoor unit 1 is decompressed by the expansion valve 21, exchanges heat with the outside air by the outdoor heat exchanger 17, evaporates, and is sucked into the compressor 15 via the four-way valve 19. .
The refrigeration cycle at this time is refrigeration cycle A → B → C → D → A drawn by a thick solid line in FIG. 9. The heating capacity at this time is P1.

(5) Thermal storage operation The thermal storage operation is an operation mode that is performed at night during off-peak hours in winter. In this operation mode, as shown in FIG. 6, the on-off valves 33, 45, and 53 of the heat storage unit device 3 are opened. The opening / closing valves 35, 37, 55, and 57 are closed. Therefore, the refrigerant circulates between the outdoor unit 1 and the heat storage unit device 3 as in the cold storage operation and does not go to the indoor unit 5 side. Specifically, the operation is as follows.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 15 is sent to the heat storage heat exchanger 27 through the four-way valve 19, the refrigerant pipe 9, the pipes 31 and 47 of the heat storage unit device 3, and the on-off valve 53. . In the heat storage heat exchanger 27, heat is exchanged with the heat storage material 25 in the heat storage tank to heat the heat storage material 25, and the heat storage material 25 stores heat as sensible heat. In the heat storage heat exchanger 27, the refrigerant condenses by applying heat to the heat storage material 25, and the high-pressure liquid refrigerant passes through the fully opened expansion valve 41, accumulator 43, opening / closing valves 45 and 33, and refrigerant pipe 7, and the outdoor unit 1. Sent to. The high-pressure liquid refrigerant sent to the outdoor unit 1 is decompressed by the expansion valve 21, exchanges heat with the outside air by the outdoor heat exchanger 17, evaporates, and is sucked into the compressor 15 via the four-way valve 19. .
The refrigeration cycle at this time is refrigeration cycle A → B → C → D → A drawn by a thick solid line in FIG. 9 as in the normal heating operation. In addition, the heat storage capacity at this time is P1.

(6) Regenerative Heating Operation Heating Regenerative Heating Operation includes a normal regenerative heating operation and a heating / removal operation that removes frost when the outdoor heat exchanger 17 is frosted during normal heating operation. There are two operation modes of simultaneous frost operation. Hereinafter, it demonstrates individually.
(i) Normal heat storage use heating operation Normal heat storage use heating operation is an operation mode performed at the peak of winter, etc. In this operation mode, as shown in FIG. 37, 45, and 55 are opened, and the on-off valves 33, 53, and 57 are closed. Accordingly, the refrigerant flows from the outdoor unit 1 to the indoor unit 5 to perform heating, and then flows through the heat storage heat exchanger 27 of the heat storage unit device 3 and returns to the outdoor unit 1 again. In this operation, the heat storage heat exchanger 27 functions as an evaporator. However, since the heat stored in the heat storage material 25 can be used as an evaporation heat source, the evaporation pressure is exchanged with the outdoor heat during normal heating operation. It can be set higher than the case of evaporating with the vessel 17. Therefore, the opening degree of the expansion valve 41 is increased.
Specifically, the operation is as follows.

  The high-temperature and high-pressure gas refrigerant discharged from the compressor 15 passes through the four-way valve 19, passes through the refrigerant pipe 9, the pipe 31 of the heat storage unit device 3, the refrigerant pipe 13, and the indoor unit side heat exchanger 59 of the indoor unit 5. Sent to. In the indoor heat exchanger 59, heating is performed by exchanging heat with indoor air, and the refrigerant condenses. The liquid refrigerant that has exited the indoor heat exchanger 59 passes through the fully opened expansion valve 61, passes through the refrigerant pipe 11, the pipe 29 of the heat storage unit device 3, the on-off valves 35 and 45, and the accumulator 43 to increase the opening degree. The pressure is reduced by the expansion valve 41 set to, and the heat storage heat exchanger 27 exchanges heat with the heat storage material 25 to heat and evaporate. The evaporated refrigerant is sent to the outdoor unit 1 via the pipe 49, the on-off valve 55, and the refrigerant pipe 7.

The refrigerant sent to the outdoor unit 1 is sucked into the compressor 15 via the fully opened expansion valve 21, the outdoor heat exchanger 17, and the four-way valve 19. At this time, since the heat of the heat storage material 25 can be used as an evaporation heat source, the suction pressure / temperature of the compressor 15 becomes higher than that during normal heating operation. Therefore, the pressure / temperature of the outlet gas refrigerant of the compressor 15 increases, the indoor air blowing temperature in the indoor heat exchanger 59 can be increased, and the heating function can be improved.
Since the heating function can be improved, if the heating capacity is the same, the refrigerant circulation amount, that is, the rotation speed of the compressor can be reduced accordingly, and the power consumption can be reduced. Alternatively, the heating capacity can be increased without increasing the power consumption by setting the same compressor speed as that in the normal operation.
This refrigeration cycle constitutes a refrigeration cycle a1 → b1 → c → d → a1 drawn by a thick broken line in FIG. Moreover, the heating capability at this time is P2.

(ii) Simultaneous heating / defrosting operation In this operation mode, the outdoor heat exchanger 1 has been frosted during normal heating operation in which the outdoor heat exchanger 1 shown in FIG. 5 functions as an evaporator. What is sometimes done.
The on-off valve of the heat storage unit device in this case is the same as the above-described normal heat storage heating operation shown in FIG.
On the other hand, the expansion valve 41 in the heat storage unit device 3 is made to be squeezed so that the evaporation pressure is lower than that of the “normal heat storage use heating operation” described above, and the degree of superheat is increased. You may restrict | squeeze to the same extent as the expansion pressure of the expansion valve 21 of the outdoor unit 1 in "normal heating operation". By doing so, the evaporative refrigerant at the outlet of the heat storage heat exchanger 27 can be given a higher degree of superheat, and excessive condensation in the outdoor heat exchanger 17 can be suppressed. The specific operation is performed as follows.

If the outdoor heat exchanger 1 is frosted during normal heating operation, the open / close state of the on-off valve of the heat storage unit device 3 is as shown in FIG.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 15 is heated in the indoor unit 5 and reaches the accumulator 43 of the heat storage unit device 3 in the same manner as the normal heat storage use heating operation described above.
The high-pressure liquid refrigerant that has passed through the accumulator 43 is depressurized by the expansion valve 41, exchanges heat with the heat storage material 25 by the heat storage heat exchanger 27, and is heated and evaporated. At this time, since the opening degree of the expansion valve 41 is more constricted than in the case of the normal heat storage utilization heating operation described above, the evaporation pressure at the outlet of the heat storage heat exchanger 27 is lowered to increase the degree of superheat to the evaporated refrigerant. Can be held large.

The evaporative refrigerant that has exited the heat storage heat exchanger 27 is sent to the outdoor unit 1 via the pipe 49, the on-off valve 55, and the refrigerant pipe 7.
The refrigerant sent to the outdoor unit 1 passes through the fully opened expansion valve 21 and is sent to the outdoor heat exchanger 17. In the outdoor heat exchanger 17, the outdoor heat exchanger 17 is warmed by the refrigerant having a high degree of heating, and frost attached to the outdoor heat exchanger 17 can be removed. The refrigerant that has passed through the outdoor heat exchanger 17 decreases the degree of superheat and is sucked into the compressor 15 via the four-way valve 19.
By performing such an operation, the heating operation can be performed while defrosting without reducing the heating capacity. Once defrosting is complete, it may be switched to normal heating operation again.
Generally, in order to perform a defrosting operation during a heating operation in a heat pump air conditioner, it is necessary to temporarily interrupt the heating operation. When there is only one outdoor unit, heating is interrupted, and when there are a plurality of outdoor units or outdoor heat exchangers, the heating capacity is significantly reduced. In the present invention, by adding the heat storage unit device to the existing heat pump air conditioner, the defrosting operation can be performed while maintaining the heating capability in addition to the improvement of the cooling / heating capability.

This refrigeration cycle constitutes a refrigeration cycle of a3 → b2 → C → D → A → a2 → a3 drawn by thick solid lines and thin broken lines in FIG. A → a2 in the refrigeration cycle indicates the degree of superheat. Further, a2 → a3 in the refrigeration cycle indicates a state in which the refrigerant vapor with the superheat degree is cooled when the frost attached to the outdoor heat exchanger 17 is removed. As can be seen from this figure, by increasing the degree of superheat A → a2, it is possible to prevent excessive condensation in the outdoor heat exchanger 17 even if the vapor refrigerant is deprived of heat during defrosting. The heating capacity at this time is P3.
In addition, as described above, the excessive condensation of the refrigerant in the outdoor heat exchanger 17 is suppressed in order to prevent the liquid from returning to the compressor 15. If the accumulator (not shown) for the compressor of the outdoor unit 1 of the existing heat pump air conditioner has a sufficient capacity to store the condensed refrigerant at the time of defrosting, the expansion of the heat storage unit device 3 Even if the opening degree of the valve 41 is increased to the same level as that of the “normal heat storage use heating operation” and the degree of superheat of the gas refrigerant entering the outdoor heat exchanger 17 is reduced, liquid return to the compressor 15 can be prevented.

As described above, in the present embodiment, the heat storage unit device 3 using the heat storage material whose melting point is higher than the evaporation temperature of the refrigerant and lower than the condensation temperature of the refrigerant is attached to the existing heat pump air conditioner. As a result, the cooling capacity and the heating capacity using latent heat can be greatly increased. Furthermore, the defrosting operation can be used together without reducing the heating capacity during the heating operation.
Moreover, since the apparatus is unitized like the heat storage unit device 3, the heat storage unit device can be added as if adding an indoor unit.

In the above embodiment, the heat storage heat exchanger is installed inside the heat storage tank, but the heat storage heat exchanger may be separated from the heat storage tank and installed outside the heat storage tank. In this case, the heat transfer medium is circulated between the heat storage tank and the heat storage heat exchanger. In addition, when the heat storage material itself has fluidity even after solidification, the heat storage material itself may be used as a heat transfer medium. Further, when the heat storage tank and the heat storage heat exchanger are separated, it is possible to install only the heat storage tank in a place away from the heat storage unit device.
In the above-described embodiment, the high-pressure liquid refrigerant is decompressed by the expansion valve. However, the expansion valve may be used to function as an expansion valve by reducing the opening degree. Furthermore, although the degree of pressure reduction cannot be adjusted, the pressure may be reduced using a capillary tube.

Further, the on-off valve used in the above embodiment may be replaced with a flow rate control valve so that the flow rate can be adjusted so that the operation modes can be combined and operated simultaneously. For example, the on-off valves 45, 53, 35, and 37 are used as flow rate control valves, and the refrigerant flows are branched and merged by appropriately adjusting the flow rate to an intermediate opening degree, respectively, and “normal cooling / cold storage simultaneous operation” or “normal heating”・ Simultaneous heat storage operation "is possible.
In particular, since the melting point of the heat storage material is Te <Tm <Te + 10 ° C. in the present invention, the evaporation temperature (evaporation pressure) in the indoor heat exchanger and the evaporation temperature (evaporation pressure) in the heat storage heat exchanger are Since the same degree is sufficient, even in the existing heat pump type air conditioning system having only two refrigerant pipes, the “normal cooling / cold storage simultaneous operation” can be easily performed.
On the other hand, when storing cold with ice, the evaporation temperature in the heat storage heat exchanger is 0 ° C. or less, and the evaporation temperature in the indoor heat exchanger is about 10 ° C. Therefore, the heat storage heat exchanger The evaporating pressure in the chamber becomes lower than the evaporating pressure in the indoor heat exchanger, and it is necessary to adjust the pressure in order to join the refrigerant pipe and flow, or three refrigerant pipes are connected to the outdoor unit according to the pressure level. Necessary between heat storage unit devices.
The flow rate may be adjusted by using the on-off valve 35 and on-off valve 45, and the on-off valve 37 and on-off valve 53 as three-way valves.
Further, in the above, the on-off valve 35 and the on-off valve 45 are set to an intermediate opening, the on-off valve 37 is fully opened, and the on-off valve 53 is fully closed, so that normal cooling and regenerative cooling simultaneous operation is also possible. In this case, it becomes possible to adjust the cool storage utilization ratio, that is, the degree of supercooling of the liquid refrigerant at the inlet of the indoor unit 5.

It is explanatory drawing explaining the structure of the heat pump type air conditioner incorporating the heat storage unit apparatus which concerns on one embodiment of this invention. It is explanatory drawing which shows the flow of the refrigerant | coolant at the time of the normal cooling operation in the heat pump type air conditioner shown in FIG. It is explanatory drawing which shows the flow of the refrigerant | coolant at the time of the cool storage driving | operation in the heat pump type air conditioner shown in FIG. It is explanatory drawing which shows the flow of the refrigerant | coolant at the time of the cool storage utilization cooling operation in the heat pump type air conditioner shown in FIG. It is explanatory drawing which shows the flow of the refrigerant | coolant at the time of the normal heating operation in the heat pump type air conditioner shown in FIG. It is explanatory drawing which shows the flow of the refrigerant | coolant at the time of the thermal heat storage driving | operation in the heat pump type air conditioner shown in FIG. It is explanatory drawing which shows the flow of the refrigerant | coolant at the time of the heat storage utilization heating operation in the heat pump type air conditioner shown in FIG. It is a Mollier diagram in a cooling-related operation mode. It is a Mollier diagram in the heating-related operation mode.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 Outdoor unit, 3 Thermal storage unit apparatus, 5 Indoor unit, 7, 9, 11, 13 Refrigerant piping, 15 Compressor, 17 Outdoor heat exchanger, 19 Four-way valve, 21 Expansion valve, 23 Thermal storage tank, 25 Thermal storage material , 27 Heat storage heat exchanger, 29, 31, 39, 47, 49, 51 Piping, 33, 35, 37, 45, 53, 55, 57 On-off valve, 41 Expansion valve, 59 Indoor heat exchanger, 61 Expansion valve.

Claims (5)

A method for enhancing the cooling / heating capacity of an existing heat pump air conditioner in which an outdoor unit and an indoor unit are connected by two refrigerant pipes,
A heat storage tank that stores the heat storage material, a heat storage material that is stored in the heat storage tank and has a melting point Tm that is higher than the evaporation temperature Te of the refrigerant in the existing heat pump air conditioner and lower than the condensation temperature Tc, and the heat storage material and the refrigerant A heat storage unit device having a heat storage heat exchanger for exchanging heat between the outdoor unit and the indoor unit in the existing heat pump air conditioner,
During the off-peak period of the cooling, the cold storage operation is performed to store the cold energy in the heat storage material in the heat storage tank. A method for enhancing the cooling / heating capacity of a heat pump air conditioner, wherein a heat storage operation is performed in which a heat storage operation is performed in which heat is stored in the heat storage material, and a heating operation is performed using the heat stored in the heat storage material at a peak. A heat storage unit device attached to an existing heat pump air conditioner in which an outdoor unit and an indoor unit are connected by two refrigerant pipes, a liquid refrigerant pipe and a gas refrigerant pipe,
A first pipe that can be inserted and connected in the middle of the liquid refrigerant pipe and has first and second on-off valves;
A second pipe that can be inserted and connected in the middle of the gas refrigerant pipe and has a third on-off valve;
A heat storage tank that stores the heat storage material, a heat storage material that is stored in the heat storage tank and has a melting point Tm that is higher than the evaporation temperature Te of the refrigerant in the existing heat pump air conditioner and lower than the condensation temperature Tc, and the heat storage material and the refrigerant Between the first and second on-off valves in the first pipe through an expansion valve and a fourth on-off valve on one end side of the heat storage heat exchanger. Connect the pipe, connect the other end of the heat storage heat exchanger via the fifth on-off valve to a position on the outdoor unit side of the second on-off valve in the second pipe, and perform the heat storage heat exchange The heat storage unit device characterized in that the other end side of the chamber is connected by piping to a position closer to the indoor unit side than the first and second opening / closing valve installation portions in the first piping via a sixth opening / closing valve. 3. The other end side of the heat storage heat exchanger is connected to a pipe via a seventh on-off valve at a position closer to the outdoor unit side than the first and second on-off valve installation parts in the first pipe. The heat storage unit device described in 1. 4. The heat storage unit device according to claim 2, wherein a melting point Tm of the heat storage material is Te <Tm <Te + 10 ° C. 5. A heat pump air conditioner, wherein the heat storage unit device according to any one of claims 2 to 4 is attached to a heat pump air conditioner having an outdoor unit and an indoor unit.

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