JP2015140952A - Heat pump type heat source machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump type heat source machine capable of preventing a liquefied refrigerant from staying in a bypass passage in which a defrosting valve is installed, and capable of reducing a filling amount of the refrigerant as much as possible.SOLUTION: A heat pump type heat source machine 3 includes a heat pump circuit 20 configured by connecting a compressor 21, a condensation heat exchanger 22, an expansion valve 23 and an evaporation heat exchanger 24 by refrigerant piping 25. The heat pump circuit 20 has a bypass passage 31 which at least bypasses the condensation heat exchanger 22, and a defrosting valve 32 installed in the bypass passage 31. When frost formation in the evaporation heat exchanger 24 is detected, the defrosting valve 32 is opened and a defrosting operation is performed. The defrosting valve 32 is installed at a position close to a branch part in which the bypass passage 31 branches from the refrigerant piping 25 between the compressor 21 and the condensation heat exchanger 22.

Description

  The present invention relates to a heat pump heat source device, and more particularly to a device that performs a defrosting operation using a defrosting valve installed in a bypass passage that bypasses a condensation heat exchanger and an expansion valve.

  2. Description of the Related Art Conventionally, heat exchange type heat pump water heaters using a refrigerant have been widely used. This type of heat pump water heater includes a heat pump heat source device that heats hot and cold water with a refrigerant, a hot water storage tank that stores heated hot water, a heating circulation circuit that circulates hot water between the heat pump heat source device and the hot water storage tank, and the like. The hot water in the hot water storage tank is circulated through a heating circuit and heated by a heat pump heat source device, and the heated hot water is returned to the hot water storage tank for storage, and then supplied from the hot water storage tank to a desired hot water supply destination such as a faucet or bath. Hot water is to be supplied.

  The above heat pump heat source machine is configured by connecting a compressor, a condensation heat exchanger, an expansion valve, and an evaporating heat exchanger via a refrigerant pipe, and uses a refrigerant enclosed in the refrigerant pipe. Hot water storage operation is performed. In this hot water storage operation, the compressor and the blower fan for the evaporative heat exchanger are respectively driven, and heat is exchanged between the refrigerant flowing through the heat pump circuit and the hot water flowing through the heating circulation circuit by the condensation heat exchanger, so that the hot water is Heated.

  By the way, in the heat pump type heat source device described above, due to the structure in which the refrigerant absorbs heat from the outside air in the evaporative heat exchanger, in the cold region and winter, the water vapor in the atmosphere adheres to the surface of the evaporative heat exchanger and freezes. Frost may occur. If frost adheres to the evaporative heat exchanger, the endothermic efficiency in the evaporative heat exchanger is significantly reduced, and as a result, the operation efficiency of the heat pump heat source apparatus is lowered.

  For this reason, the heat pump heat source machine is generally provided with a function of a defrosting operation for stopping the hot water storage operation and removing frost adhering to the evaporation heat exchanger. As a function of such a defrosting operation, various techniques described below have been put into practical use.

  For example, a four-way valve is provided in the compressor, and during defrosting operation, the refrigerant flows through the four-way valve in the opposite direction to that during normal operation, and the refrigerant (hot gas) that has been heated to high temperature and high pressure by the compressor is evaporated and exchanged. Defrosting is performed by pouring directly into the vessel and melting the frost adhering to the evaporative heat exchanger.

  Moreover, in the heat pump water heater described in Patent Document 1, a bypass passage that bypasses the condensation heat exchanger is provided, a defrost valve is installed in the bypass passage, and the defrost valve is opened during the defrosting operation. The refrigerant heated by the compressor is directly flowed to the evaporative heat exchanger through the bypass passage to remove frost on the evaporative heat exchanger.

JP 2006-220357 A

  By the way, during the normal hot water storage operation, in the structure of the heat pump water heater of Patent Document 1, since the bypass passage is always closed by the defrost valve, the refrigerant flowing from the refrigerant pipes is retained in the bypass passage. In particular, a high-temperature and high-pressure gaseous refrigerant flows into the bypass passage upstream of the defrost valve from the refrigerant pipe between the compressor and the condensation heat exchanger.

  However, the length of the bypass passage and the installation location of the defrost valve are determined according to the arrangement of the heat pump heat source equipment, so the defrost valve is installed away from the branch where the bypass passage branches from the refrigerant pipe. Then, the refrigerant that has flowed into the bypass passage on the upstream side from the defrost valve is gradually liquefied due to the temperature gradually decreasing due to the influence of the outside air temperature or the like. The liquid refrigerant staying in the bypass passage does not contribute to the operation of the heat pump cycle, and if the liquefied refrigerant stays in comparison with the gaseous refrigerant, it is necessary to increase the filling amount of the refrigerant. As a result, the heat pump There is a problem that the operating efficiency of the heat source machine decreases.

  An object of the present invention is to provide a heat pump heat source device capable of preventing liquefied refrigerant from staying in a bypass passage where a defrost valve is installed, and to provide a heat pump heat source device capable of reducing the amount of refrigerant charged as much as possible. Providing, etc.

  The heat pump heat source apparatus according to claim 1 is a heat pump heat source apparatus including a heat pump circuit configured by connecting a compressor, a condensing heat exchanger, an expansion means, and an evaporating heat exchanger with a refrigerant pipe, The heat pump circuit has at least a bypass passage that bypasses the condensing heat exchanger and a defrost valve installed in the bypass passage, and when the frost formation of the evaporative heat exchanger is detected, the defrosting In a heat pump heat source apparatus that performs a defrosting operation by opening a valve, the defrosting valve is close to a branch portion where the bypass passage branches from the refrigerant pipe between the compressor and the condensing heat exchanger. It is characterized by being installed in a position.

  The heat pump heat source apparatus according to claim 2 is the invention according to claim 1, wherein the bypass passage includes an upstream bypass passage portion connecting the branch portion and an inlet side of the defrost valve, and the upstream bypass passage. The passage portion is characterized in that it is constituted by a connecting pipe that is integrally provided in the defrost valve.

  According to a third aspect of the present invention, in the heat pump type heat source apparatus according to the second aspect of the present invention, the branch portion is formed of a T-shaped connecting joint member, and the connecting pipe is directly connected to the connecting joint member.

  According to the first aspect of the present invention, the defrost valve is installed at a position close to the branch portion where the bypass passage branches from the refrigerant pipe between the compressor and the condensation heat exchanger. The length of the bypass passage between the valves can be shortened.

  Therefore, by appropriately disposing the defrost valve near the refrigerant pipe, the amount of refrigerant staying in the bypass passage upstream of the defrost valve can be reduced. The temperature of the high-temperature and high-pressure refrigerant flowing through the refrigerant pipe can be used to prevent the liquefaction of the refrigerant flowing into the bypass passage from the refrigerant pipe. A decrease in operating efficiency of the heat source machine can be prevented.

  According to the invention of claim 2, the bypass passage has an upstream bypass passage portion that connects the branch portion and the inlet side of the defrost valve, and the upstream bypass passage portion is provided integrally with the defrost valve. Therefore, the upstream bypass passage can be made compact. Since the defrost valve and the upstream bypass passage can be assembled as an integrated product in the heat pump heat source machine, workability is improved.

  According to the invention of claim 3, the branch portion is formed of a T-shaped connecting joint member, and the connecting pipe is directly connected to the connecting joint member, so that a piping member for connecting the refrigerant pipe and the defrost valve is not required. Thus, the number of parts is reduced, and the number of work points is reduced by reducing the number of brazing points, and the work for attaching to the refrigerant pipe in the upstream bypass passage is simplified.

It is a schematic block diagram of the heat pump hot-water supply apparatus which concerns on the Example of this invention. It is a schematic block diagram of refrigerant | coolant piping, a bypass channel | path, and a defrost valve.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

First, the whole structure of the heat pump hot water supply apparatus 1 is demonstrated.
As shown in FIG. 1, a heat pump hot water supply apparatus 1 controls a hot water storage hot water supply apparatus 2 having a hot water storage tank 5 for storing hot water, a heat pump heat source apparatus 3 for heating hot water in the hot water storage tank 5, and a heat pump hot water supply apparatus 1. It comprises circulation pipes 8a and 8b for circulating hot water between the control unit 4, the hot water storage hot water supply device 2 and the heat pump heat source unit 3.

  As shown in FIG. 1, a hot water storage and hot water supply apparatus 2 includes a hot water storage tank 5 having a vertically long cylindrical outer peripheral surface, various pipes 6, 7, 8 a and 8 b, a hot water circulation pump 11, an on-off valve 12, a mixing valve 13, A control unit 16, an outer case 17, and the like are provided. The hot water storage tank 5 stores high-temperature hot water (for example, 65 to 90 ° C.) heated by the heat pump heat source unit 3.

  A water supply pipe 6 and a circulation pipe 8 a are connected to the lower end of the hot water storage tank 5. The water supply pipe 6 is provided with an on-off valve 12 for supplying low temperature clean water to the hot water storage tank 5. A circulation pipe 8b and a hot water discharge pipe 7 are connected to the upper end of the hot water storage tank 5, and hot hot water returned from the circulation pipe 8b is stored in the hot water storage tank 5. When hot water is supplied, the high temperature in the hot water storage tank 5 is stored. Hot water can be supplied to the hot water supply pipe 7.

  In the hot water storage tank 5, a plurality of temperature sensors 5 a to 5 d are arranged at predetermined intervals in the height direction, and temperature detection signals from the temperature sensors 5 a to 5 d are supplied to the main control unit 16. The outer case 17 is formed in a thin steel plate box shape, and includes a hot water storage tank 5, various pipes 6 and 7, a part of the circulation pipes 8 a and 8 b, a hot water circulation pump 11, an on-off valve 12, a mixing valve 13, Various temperature sensors 15a to 15d, a main control unit 16 and the like are accommodated.

Next, the heat pump type heat source device 3 according to the present invention will be described.
As shown in FIG. 1, the heat pump heat source unit 3 includes a heat pump circuit 20 that heats hot and cold water with a refrigerant, an auxiliary control unit 43 that is connected to the main control unit 16 and controls the heat pump circuit 20, and an outer case 45 that houses them. Etc.

  The heat pump circuit 20 includes a compressor 21, a condensing heat exchanger 22 for heating hot water, an expansion valve 23 for rapidly expanding a high-pressure refrigerant to lower the temperature and pressure, and an evaporation heat exchanger 24 for absorbing outside air heat, These devices 21 to 24 are configured to be connected via a refrigerant pipe 25 and perform a hot water storage operation using the refrigerant accommodated in the refrigerant pipe 25. The heat pump circuit 20 further includes a blower fan 27 for an evaporation heat exchanger driven by a blower motor 27a, a bypass passage 31 and a defrost valve 32 for a defrosting operation.

  The compressor 21 is a known hermetic compressor that adiabatically compresses a refrigerant in a gas phase state to increase the temperature.

  The condensing heat exchanger 22 is configured by a double pipe having a heat exchanger passage portion 22 a installed between the circulation pipes 8 a and 8 b and an internal passage 22 b that is a part of the refrigerant pipe 25. In the condensation heat exchanger 22, heat is exchanged between the refrigerant flowing in the internal passage 22b and hot water supplied from the circulation pipe 8a to the heat exchanger passage portion 22a, and the hot water is heated and the refrigerant is cooled and liquefied.

  The expansion valve 23 (corresponding to the expansion means) adiabatically expands the liquid phase refrigerant and lowers the temperature. The expansion valve 23 is a control valve having a variable throttle amount. An expansion valve with a constant throttle amount may be used instead of the expansion valve 23 with a variable throttle amount.

  The evaporative heat exchanger 24 has an evaporator passage portion 24a included in the refrigerant pipe 25, and the evaporator passage portion 24a has a heat transfer tube and a plurality of fins. In the evaporative heat exchanger 24, heat is exchanged between the refrigerant flowing through the evaporator passage portion 24a and the outside air, and the refrigerant absorbs heat from the outside air and vaporizes.

  The refrigerant pipe 25 includes a refrigerant passage 25 a that connects the discharge side of the compressor 21 and the inlet side of the condensation heat exchanger 22, and a refrigerant passage 25 b that connects the outlet side of the condensation heat exchanger 22 and the inlet side of the expansion valve 23. , A refrigerant passage 25c that connects the outlet side of the expansion valve 23 and the inlet side of the evaporation heat exchanger 24, and a refrigerant passage 25d that connects the outlet side of the evaporation heat exchanger 24 and the introduction side of the compressor 21 are provided. .

  The refrigerant pipe 25 is provided on the discharge side of the compressor 21 and detects the temperature of the refrigerant discharged from the compressor 21. The refrigerant discharge side temperature sensor 29 a is provided on the inlet side of the expansion valve 23 and flows into the expansion valve 23. An expansion valve inlet side temperature sensor 29b for detecting the refrigerant temperature to be detected, an expansion valve outlet side temperature sensor 29c provided on the outlet side of the expansion valve 23 and detecting the refrigerant temperature flowing out of the expansion valve 23, and an outlet of the evaporative heat exchanger 24 An evaporative heat exchanger outlet side temperature sensor 29d that detects the temperature of the refrigerant flowing out from the evaporative heat exchanger 24 is provided.

  The refrigerant pipe 25 is provided with a bypass passage 31 connected to the refrigerant passage 25a and the refrigerant passage 25c so as to bypass the condensation heat exchanger 22 and the expansion valve 23.

  The bypass passage 31 is provided with a defrost valve 32 that is connected in parallel to the condensation heat exchanger 22 and the expansion valve 23 and that is controlled to open and close by the auxiliary control unit 43 during the defrost operation. When the frost formation of the evaporative heat exchanger 24 is detected, the defrost valve 32 is opened and the defrost operation is performed. In addition, the specific structure of the bypass passage 31 and the defrost valve 32 relevant to this invention is mentioned later.

  During the hot water storage operation of the heat pump heat source device 3, the heated refrigerant compressed to a high pressure by the compressor 21 is sent to the condensation heat exchanger 22 and circulated from the lower end of the hot water storage tank 5 by driving the hot water circulation pump 11. Heat is exchanged with the water flowing into the heat exchanger passage 22a through the piping 8a for heating and warming the water, and the liquefied refrigerant is cooled to the expansion valve 23. The heated hot water passes through the circulation piping 8b. The hot water is stored in the hot water storage tank 5 of the hot water storage hot water supply device 2 and the hot water is stored in the hot water storage tank 5 by repeating the heating operation via the heat pump heat source unit 3.

  The heat pump hot water supply apparatus 1 is controlled by a control unit 4 including a main control unit 16 and an auxiliary control unit 43. Detection signals from various temperature sensors and the like are transmitted to the control unit 4, and the control unit 4 controls the operation of the hot water storage hot water supply device 2 and the heat pump heat source unit 3, the operation / stop of various pumps, and the open / close states of various valves. Various operations (hot water storage operation, hot water supply operation, defrosting operation, etc.) are executed by controlling switching and opening degree adjustment.

  The main control unit 16 can communicate data with the operation remote controller 46 that can be operated by the user. When the target hot water temperature is set by operating the switch of the operation remote controller 46, the target hot water temperature data is transferred from the operation remote controller 46. It is transmitted to the main control unit 16. The auxiliary control unit 43 is capable of data communication with the main control unit 16, and in accordance with instructions from the main control unit 16, various devices (the compressor 21, the expansion valve 23, the blower motor 27 a, the removal device) of the heat pump heat source unit 3. Drive control of the frost valve 32 and the like is performed.

Here, the specific structures of the bypass passage 31 and the defrost valve 32 related to the present invention will be described.
As shown in FIGS. 1 and 2, the bypass passage 31 is branched from the refrigerant passage 25 a and connected to the refrigerant passage 25 c to constitute a defrost circuit that bypasses the condensation heat exchanger 22 and the expansion valve 23. An upstream bypass passage portion 31a connecting the refrigerant passage 25a and the inlet side 35a of the defrost valve 32, and a downstream bypass passage portion 31b connecting the outlet side 35b of the defrost valve 32 and the refrigerant passage 25c. And have.

  As shown in FIG. 2, the defrost valve 32 is installed at a position close to the refrigerant passage 25a through which a high-temperature and high-pressure gaseous refrigerant flows. That is, the defrost valve 32 is installed at a position close to the branch portion 30 where the bypass passage 31 branches from the refrigerant passage 25 a between the compressor 21 and the condensation heat exchanger 22. The defrost valve 32 includes a solenoid 33 including a plunger 33a (movable iron core), a plug nut 33b (fixed iron core), a coil 33c, a yoke 33d, and a valve body 34a, a valve seat 34b, a flow path hole 34c, and the like. It is comprised with the well-known electromagnetic on-off valve provided with the part 34. FIG.

  Further, the defrost valve 32 includes a block-shaped valve case member 35 made of brass, and the valve case 34 is provided on the valve case member 35. The valve case member 35 includes an upstream straight pipe 36 (corresponding to a connecting pipe) extending in a direction perpendicular to the axis of the defrost valve 32 and a downstream straight pipe extending in a direction parallel to the axis of the defrost valve 32. A tube 37 is integrally provided. That is, the downstream end of the upstream straight pipe 36 is connected by brazing to an inlet side 35 a that opens to the side surface of the valve case member 35, and the upstream end of the downstream straight pipe 37 opens to the bottom of the valve case member 35. Connected to the outlet side 35b.

  In the bypass passage 31, the upstream bypass passage portion 31 a is configured by an upstream straight pipe 36. The branch portion 30 of the refrigerant passage 25a is constituted by a T-shaped connecting joint member 38 (so-called cheese), and the upstream end of the upstream straight pipe 36 is directly connected to the connecting joint member 38 by brazing. The upstream end of the downstream bypass passage portion 31 b is configured by a downstream straight pipe 37. The downstream end of the downstream straight pipe 37 is connected to most piping members 39 constituting the downstream bypass passage portion 31b via a connection joint member 39a.

  The upstream straight pipe 36 has such a length (for example, about 30 to 40 mm) that the refrigerant staying in the upstream straight pipe 36 can maintain substantially the same temperature as the refrigerant flowing through the refrigerant passage 25a during hot water storage operation. It is desirable to set.

  The defrost valve 32 has a flow passage hole 34c having a cross-sectional area smaller than that of the bypass passage 31 even in the fully opened state. That is, since the defrost valve 32 has a throttling function even in the fully opened state, a temperature difference or a pressure difference exists between the refrigerant on the inlet side 35a and the outlet side 35b of the defrost valve 32. For this reason, at the time of defrosting operation, although it is lower than the refrigerant discharge temperature of the compressor 21 at the time of normal hot water storage operation, a high-temperature refrigerant can be sent to the evaporation heat exchanger 24.

Next, the operation and effect of the heat pump heat source apparatus 3 of the present invention will be described.
During the hot water storage operation of the heat pump heat source device 3, if the temperature of the refrigerant flowing out from the evaporating heat exchanger 24 detected by the evaporating heat exchanger outlet side temperature sensor 29d becomes equal to or lower than a set temperature (for example, 0 ° C. to −7 ° C.) A defrosting operation is started in order to remove frost adhering to the heat exchanger 24.

  In the defrosting operation, the control unit 4 stops the blower fan 27, switches the defrost valve 32 to the open state, and switches the expansion valve 23 to the fully closed state. Then, the high-temperature and high-pressure refrigerant discharged from the compressor 21 does not flow to the condensation heat exchanger 22 but flows to the evaporation heat exchanger 24 through the bypass passage 31 and melts frost attached to the evaporation heat exchanger 24. Defrosting is performed.

  By the way, during the hot water storage operation of the heat pump heat source unit 3, the defrost valve 32 maintains the closed state, so that the refrigerant stays in the upstream bypass passage portion 31a and the downstream bypass passage portion 31b of the bypass passage 31. End up. In the downstream bypass passage 31b, the temperature of the refrigerant is unlikely to decrease due to the relationship between the outside air temperature and the evaporation temperature, and therefore, the same gaseous refrigerant as the refrigerant flowing from the expansion valve 23 to the evaporation heat exchanger 24 stays.

  A high-temperature and high-pressure gaseous refrigerant flowing from the compressor 21 to the condensation heat exchanger 22 flows into the upstream bypass passage portion 31a. However, the upstream side of the defrost valve 32 is located upstream of the refrigerant passage 25a. The side bypass passage portion 31a is shortened, and the heat of the refrigerant flowing through the refrigerant passage 25a is efficiently transferred to the refrigerant staying in the upstream side bypass passage portion 31a, so that a decrease in the refrigerant temperature is suppressed and liquefaction of the refrigerant is prevented. Is done.

  Therefore, by appropriately disposing the defrost valve 32 near the refrigerant pipe 25, the amount of refrigerant staying in the bypass passage 31 upstream of the defrost valve 32 can be reduced. Since the temperature of the high-temperature and high-pressure refrigerant flowing through the refrigerant passage 25a can be used to prevent liquefaction of the refrigerant flowing into the bypass passage 31 from the refrigerant pipe 25, the amount of refrigerant filled in the refrigerant pipe 25 can be reduced as much as possible. Thus, it is possible to prevent the operating efficiency of the heat pump heat source unit 3 from being lowered.

  In addition, the upstream bypass passage portion 31a is configured by an upstream straight pipe 36 that is integrally provided in the defrost valve 32, and the upstream straight pipe 36 is directly connected to the connection joint member 38. When the pipe member for connecting the pipe 25 and the defrost valve 32 is not required, the number of parts is reduced, the number of work is reduced by reducing the brazing points, and the upstream side bypass passage 31a is attached to the refrigerant pipe 25 Will be easier.

Next, a mode in which the above embodiment is partially changed will be described.
[1] In the above embodiment, the bypass passage 31 is provided so as to bypass the condensing heat exchanger 22 and the expansion valve 23, but if the expansion valve 23 can be set to a fully open state during the defrosting operation. Alternatively, it may be provided so as to bypass only the condensation heat exchanger 22.

[2] In the above-described embodiment, the upstream straight pipe 36 is applied as the connection pipe, but it is not particularly limited to this shape, and an L-shaped pipe may be applied as the connection pipe. The shape of the connecting pipe can be changed as appropriate.

[3] In addition, those skilled in the art can implement the present invention in various forms with various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. It is.

3 Heat Pump Heat Source Machine 20 Heat Pump Circuit 21 Compressor 22 Condensation Heat Exchanger 23 Expansion Valve 24 Evaporation Heat Exchanger 25 Refrigerant Pipe 30 Branch Port 31 Bypass Path 31a Upstream Bypass Path Section 32 Defrost Valve 36 Upstream Straight Pipe 38 Connection Joint member

Claims (3)

A heat pump heat source apparatus including a heat pump circuit configured by connecting a compressor, a condensation heat exchanger, an expansion means, and an evaporative heat exchanger with refrigerant piping, wherein the heat pump circuit includes at least the condensation heat exchanger. When the frost formation of the evaporative heat exchanger is detected, the defrost valve is opened to perform the defrosting operation. In heat pump type heat source machine,
The heat pump heat source apparatus, wherein the defrost valve is installed at a position close to a branch portion where the bypass passage branches from the refrigerant pipe between the compressor and the condensation heat exchanger. The bypass passage has an upstream bypass passage portion that connects the branch portion and the inlet side of the defrost valve,
The heat pump heat source apparatus according to claim 1, wherein the upstream bypass passage is configured by a connection pipe that is integrally provided in the defrost valve. The heat pump heat source apparatus according to claim 2, wherein the branch portion is formed of a T-shaped connection joint member, and the connection pipe is directly connected to the connection joint member.