JP5516332B2 - Heat pump type hot water heater - Google Patents

Description

  The present invention can perform defrosting operation without mounting a four-way valve by storing heat in the water-refrigerant heat exchanger before performing defrosting operation and performing defrosting operation during hot water heating operation by heat pump operation. The present invention relates to a heat pump type hot water heater.

  Conventionally, a defrosting method of this type of heat pump type hot water heater generally employs a defrosting method in which a four-way valve is switched and a refrigerant in a refrigeration cycle flows in the reverse direction.

  That is, in the defrosting operation, the flow direction of the refrigerant is the same as that during cooling, and a high-temperature and high-pressure refrigerant is passed through the outdoor heat exchanger to melt frost adhering to the heat exchanger.

  In this defrosting method, the water-refrigerant heat exchanger becomes an evaporator during defrosting, so when the temperature of water is low during defrosting operation or when the flow rate of water drops due to problems such as dust However, there was a basic problem that the water in the water-refrigerant heat exchanger was frozen due to a further decrease in the temperature of the water.

  As countermeasures against this basic problem, generally, a method of heating with a heater so that the temperature of hot water does not decrease during defrosting operation can be considered, and a method of responding by replacing water with antifreeze is proposed and implemented. It has been. In hot water supply equipment, as a method of defrosting operation, a method of performing a defrosting operation while maintaining a heating operation circuit without switching a four-way valve has been proposed and implemented.

  FIG. 8 is a configuration diagram of a refrigeration cycle and a water circuit of a conventional hot water supply apparatus.

  As shown in the figure, a heat pump circuit in which a compressor 111, a hot water supply heat exchanger 112, an expansion valve 113A, and an evaporator 114 are connected by piping, a hot water storage tank 120, and a fluid circuit in which a fluid circulation pump 123 is connected by piping. A heat pump hot water supply apparatus having a defrosting start determining means for determining the start of defrosting, and reducing the flow rate of the fluid circulation pump 123 before or after the defrosting start determination, and generating a minimum flow rate of the fluid circulation pump 123 An invention that operates in a region close to this region is disclosed (for example, see Patent Document 1).

JP-A-2005-147609

  However, in this refrigeration cycle method, the amount of heat of the compressor used for the defrosting operation is small, and defrosting may not be completed within the time.

  In the case of a hot water heater used in a cold region, if the heating refrigerant in the heat pump circuit is passed through the water-refrigerant heat exchanger, the amount of heat necessary for defrosting is taken away by the water-refrigerant heat exchanger. In some cases, frost cannot be melted and remains due to poor defrosting.

  In general, in the defrosting operation using the four-way valve switching method, the method of increasing the temperature of the water circuit with the heater is also inefficient in operation during the defrosting operation, and adding the heater increases the product cost. There are many issues.

  This invention solves the said conventional subject, and it aims at providing the heat pump type hot water heater which can implement | achieve a low-cost and highly efficient defrost operation.

  In order to achieve the above object, a heat pump hot water heater of the present invention includes a heat pump cycle in which a compressor, a water-refrigerant heat exchanger, a decompressor, and an air heat exchanger are sequentially connected, and the water-refrigerant heat exchanger. And a hot water circuit having a hot water circulation means and a control device, during the transition from the normal operation to the defrosting operation, the operation of the heat pump cycle is continued, and the opening of the decompressor is operated in the closing direction. At the same time, the operation of the hot water circulation means is stopped to raise the temperature of the water-refrigerant heat exchanger, and then the decompressor is operated in the opening direction.

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump type hot water heater which can implement | achieve a low-cost and highly efficient defrost operation can be provided.

The block diagram of the heat pump type hot water heater in Embodiment 1 of this invention The figure which shows the flow of the refrigerant and warm water of the heat pump type warm water heater Block diagram of the control device for the heat pump type hot water heater Operation time chart of the heat pump type hot water heater The figure which shows the flow of the refrigerant | coolant and warm water of the heat pump type hot water heater of Embodiment 2 of this invention Operation time chart of the heat pump type hot water heater The block diagram of the heat pump type hot water heater in Embodiment 3 of this invention Configuration diagram of conventional heat pump water heater

  A first invention includes a heat pump cycle in which a compressor, a water-refrigerant heat exchanger, a decompressor, and an air heat exchanger are sequentially connected, the water-refrigerant heat exchanger, a hot water circuit having hot water circulation means, and a control device When the transition from the normal operation to the defrosting operation is performed, the operation of the heat pump cycle is continued, the opening of the decompressor is operated in the closing direction, and the operation operation of the hot water circulation means is stopped. Then, after raising the temperature of the water-refrigerant heat exchanger, the heat pump hot water heater is characterized in that the decompressor is operated in the opening direction.

  Thereby, since the defrosting operation can be performed using the heat stored by the heat pump without mounting the four-way valve on the product, an operation with high efficiency during the defrosting operation can be performed. Moreover, since this structure utilizes the heat storage amount in order to increase the defrosting power, the defrosting operation can be completed in an earlier time than the operation of defrosting only with the input heat of the compressor.

  In addition, since the four-way valve is not mounted, the heat loss between the refrigerant discharged and the suction refrigerant inside the four-way valve is eliminated in the operation for normal hot water heating, and the operation efficiency is increased. In addition, the structure is simplified and the material cost is low.

  In addition, there is no problem of refrigerant noise due to the defrosting by switching the four-way valve or the problem that the chilled water circulates in the panel and the panel temperature decreases, and the user is unaware that the user has entered the defrosting operation during the defrosting operation. I don't feel it.

  The second invention is characterized in that after the operating frequency of the compressor is reduced, the operation of the hot water circulation means is stopped.

  As a result, when the pump that is the hot water circulation means is stopped, the normal operating frequency of the compressor suddenly increases the pressure and exceeds the allowable pressure of the compressor. By setting the operating frequency with the highest permissible pressure, the refrigerant circulation rate of the compressor is reduced, the pressure load due to the rapid increase in the compressor pressure is reduced, and the heat for higher defrosting is accelerated. You can store heat.

  In addition, rapid pressure fluctuations and oil discharge of the compressor due to high-frequency operation are reduced, and highly reliable operation with secured oil can be achieved.

  3rd invention provides the condensation temperature detection means which detects the refrigerant | coolant condensing temperature of the said water-refrigerant heat exchanger, and after the temperature detected by the said condensation temperature detection means reaches | attains the set condensation temperature, the said pressure reduction The container is operated in the opening direction.

  Thereby, a certain amount of heat storage before the defrosting operation can be stored in the water-refrigerant heat exchanger while ensuring the reliability of the compressor. Incidentally, the maximum condensation temperature is about 55 ° C. Since this heat storage amount can be secured at a constant level, the defrosting power during the defrosting operation can also be secured at a constant level.

  According to a fourth aspect of the present invention, the opening of the decompressor is operated in the opening direction, and the blower that blows air to the hot water circulation means and the air heat exchanger is stopped when the opening is substantially fully open.

  Thus, the stored heat and the input heat of the compressor can be reliably utilized for defrosting the air heat exchanger without radiating to the outside air.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a configuration diagram of a heat pump type hot water heater according to the present invention. In the figure, an outdoor unit 20 includes a heat pump circuit including a compressor 1, a water-refrigerant heat exchanger 2, a decompressor 3, and an air heat exchanger 4, a blower 5 for blowing air to the air heat exchanger 4, and hot water. A return pipe 11, a water supply tank 12, a pump 13 as a hot water circulation means, a hot water outlet pipe 14, a thermal valve a15a, a thermal valve b15b, a thermal valve c15c, and a thermal valve hot water circuit comprising a thermal valve d15d are arranged. It is installed. The decompressor 3 here may be an electromagnetic expansion valve.

  Terminal panels (floor warm panels) 16 and 17 are connected to the warm water return pipe 11 and warm water forward pipe 14, and a remote controller 18 for a user to set the temperature of the terminal panels (floor warm panels) 16 and 17 is provided. is set up.

  Further, although the positions of the water supply tank 12 and the pump 13 are between the hot water outlet pipe 14 and the water-refrigerant heat exchanger 2, they are not limited, and therefore the hot water return pipe 11 and the water-refrigerant heat exchanger 2 It may be in between.

  FIG. 2 is a diagram illustrating a refrigerant flow and a hot water flow in the heat pump hot water heater according to the first embodiment of the present invention. The refrigerant flow is indicated by arrows, and the hot water flow is indicated by block arrows.

If it is determined that the defrosting operation is started before the defrosting operation, the pump 13 is stopped and the flow of the water circuit is stopped. The operation of the compressor 1 on the heat pump side is not stopped while the pump 13 is stopped, and the heating operation is continued to store the heat obtained by the heat pump in the water-refrigerant heat exchanger 2.

  FIG. 3 is a block diagram of the control device for the heat pump hot water heater according to the first embodiment of the present invention. As shown in FIG. 3, when the defrost start determination is made by the defrost start determination means 57 on the outdoor unit 20 side and it is determined that the heat storage operation is before the start of defrosting, the compressor operation means 51 and the decompressor opening variable The defrosting start determination is transmitted to the means 52, the fan operating means 53, the defrosting start receiving means 60 for controlling the water circuit, the pump operating means 65, the thermal valve 15a opening / closing means 61, the thermal valve 15b opening / closing means 62, the heat Control is performed by the valve 15c opening / closing means 63 and the heat valve 15d opening / closing means 64, and after the heat storage operation, the operation moves to the defrosting operation.

  Further, a condensing temperature detecting means 54 for detecting the temperature of the water-refrigerant heat exchanger 2 and an air heat exchanger temperature detecting means 55 are arranged. In this block diagram, the defrosting start signal and the reception signal are separated, but the separation of the microcomputers is not limited, and may be handled by one microcomputer.

  FIG. 4 is a time chart showing the behavior when the heat pump type hot water heater according to Embodiment 1 of the present invention is operated.

  When the defrosting transition is determined, the process proceeds from the hot water heating operation by the heat pump in step 1 to the heat storage operation in step 2. At this time, the operating frequency of the compressor 1 is lowered to a predetermined frequency, and at the same time, the throttle direction is controlled so that the opening degree of the decompressor 3 also becomes the opening degree (closed direction) corresponding to the frequency of the compressor 1. .

  At this time, the operation of the pump 13 is stopped after a certain time from the defrosting transition determination. In the section of Step 2, the water-refrigerant heat exchanger 2 stores the heat obtained by the heat pump.

  Next, when shifting from step 2 to step 3, when the condensation temperature of the water-refrigerant heat exchanger 2 reaches a certain set temperature, it is determined that heat can be stored, and the process proceeds to the next step 3.

  Next, in step 3, the opening of the decompressor 3 is controlled to be fully open or close to full open, and the blower 5 is stopped and defrosting is started. In addition, after the start of step 3, the frequency of the compressor 1 is increased after a certain time to increase the defrosting power. The pump is also stopped.

  Next, in step 4, the defrosting operation is continued, and when the temperature of the air heat exchanger 4 becomes equal to or higher than a set temperature (about 4 ° C.), the temperature of the air heat exchanger 4 is further determined from the determination of the completion of the defrosting. In order to raise the pressure, the throttle opening degree of the decompressor 3 is controlled slightly in the closing direction (about 400 pulses).

  Next, after the defrosting is determined, the process proceeds from step 4 to step 5. At this time, the compressor 1 frequency shifts to an operation frequency at which normal warm water heating is started. The decompressor 3 also shifts to the opening degree control at the start, and the blower 5 is also operated to return to the hot water heating operation. At this time, the pump 13 operates at a low rotation speed at the time of start-up, and shifts to a normal rotation speed after a certain time. After step 5, the normal heat pump warm water heating operation is resumed.

  In the first embodiment, the operating frequency of the compressor 1 is changed. However, the constant temperature compressor 1 can also perform heat storage heating and then perform a defrosting operation.

  Here, the start determination of defrosting is generally detected and controlled by the temperature and temperature change of the air heat exchanger 4, the outside air temperature, the operation time of the compressor 1, and the like.

(Embodiment 2)
FIG. 5 is a configuration diagram of the heat pump hot water heater according to the second embodiment of the present invention, and shows the flow of refrigerant and the flow of hot water.

  In the figure, the outdoor unit 20 includes a heat pump circuit including a compressor 1, a water-refrigerant heat exchanger 2, a decompressor 3, and an air heat exchanger 4, and air is sent to the air heat exchanger 4. The thermal motion consisting of the blower 5, the hot water return pipe 11, the feed water tank 12, the pump 13 as the hot water circulation means, the hot water outlet pipe 14, the thermal valve a15a, the thermal valve b15b, the thermal valve c15c, and the thermal valve d15d. A valve hot water circuit is provided.

  Terminal panels (floor warm panels) 16 and 17 are connected to the warm water return pipe 11 and warm water forward pipe 14, and a remote controller 18 for a user to set the temperature of the terminal panels (floor warm panels) 16 and 17 is provided. is set up.

  In this arrangement, the water supply tank 12 is more efficient because it does not lengthen the operation of the pump 13 when it is between the hot water return pipe 11 and the water-refrigerant heat exchanger 2.

  FIG. 6 is a time chart showing the behavior when the heat pump type hot water heater according to Embodiment 2 of the present invention is operated, from Step 1 to Step 3 of the heat storage operation before the defrost operation and the start of the defrost operation. Is the same as that of the first embodiment, and is omitted.

  When the condensation temperature of the water-refrigerant heat exchanger 2 is lowered during the defrosting operation of step 4, the pump 13 is only used for replacing the water in the water supply tank 12 with the water in the water-refrigerant heat exchanger 2. Is operated to increase the temperature of the water-refrigerant heat exchanger 2 to increase the defrosting power.

(Embodiment 3)
FIG. 7 is a configuration diagram of the heat pump hot water heater according to Embodiment 3 of the present invention. As a configuration on the heat pump side, the outdoor unit 20 is provided with a compressor 1, a decompressor 3, and an air heat exchanger 4, and the indoor unit 21 is provided with a hot water return pipe 11, a water-refrigerant heat exchanger 2, a water supply tank 12, a pump 13, and a hot water discharge pipe 14. The outdoor unit 20 and the indoor unit 21 are connected by a refrigerant connection pipe 22.

  Thus, the type in which the outdoor unit 20 and the indoor unit 21 are separated can be expected to have the same effect as the integrated type of the outdoor unit 20, and is included in the present invention.

  As described above, the heat pump type hot water heater of the present invention can realize a defrosting operation with high efficiency at a low cost, and therefore can be applied to the development of large-sized commercial equipment.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Water-refrigerant heat exchanger 3 Pressure reducer 4 Air heat exchanger 5 Blower 11 Hot water return piping 12 Water supply tank 13 Pump (hot water circulation means)
14 Hot water outlet pipe 15a Thermal valve a
15b Thermal valve b
15c Thermal valve c
15d Thermal valve d
16 Panel a
17 Panel b
18 Operation remote control 20 Outdoor unit

Claims (4)

A normal operation is provided with a heat pump cycle in which a compressor, a water-refrigerant heat exchanger, a decompressor, and an air heat exchanger are sequentially connected, the water-refrigerant heat exchanger, a hot water circuit having hot water circulation means, and a control device. During the transition from the defrosting operation to the defrosting operation, the operation of the heat pump cycle is continued, the opening of the pressure reducer is operated in the closing direction, and the operation of the hot water circulation means is stopped, so that the water − A heat pump type hot water heater characterized by operating the decompressor in the opening direction after raising the temperature of the refrigerant heat exchanger. 2. The heat pump type hot water heater according to claim 1, wherein after the operating frequency of the compressor is reduced, the operation of the hot water circulation means is stopped. Condensation temperature detecting means for detecting the refrigerant condensing temperature of the water-refrigerant heat exchanger is provided, and the decompressor is operated in the opening direction after the temperature detected by the condensing temperature detecting means reaches the set condensing temperature. The heat pump type hot water heater according to claim 1 or 2, wherein the heat pump type hot water heater is used. 4. The air blower that blows air to the hot water circulation means and the air heat exchanger is stopped when the opening of the decompressor is operated in the opening direction and is substantially fully open. The heat pump type hot water heater described in 1.