WO2010076858A1

WO2010076858A1 - Heat pump type water heater

Info

Publication number: WO2010076858A1
Application number: PCT/JP2009/061944
Authority: WO
Inventors: 秀樹吉井
Original assignee: 三菱電機株式会社
Priority date: 2009-01-05
Filing date: 2009-06-30
Publication date: 2010-07-08
Also published as: EP2375195A4; EP2375195B1; JP5713536B2; EP2375195A1; US20110214444A1; JP2010156523A

Abstract

Provided is a heat pump type water heater, which has a small number of parts, which has a simple structure but can prevent the freeze of a drain pan, and which has a drain residual hardly left in a drain pan. The heat pump type water heater comprises a refrigerating cycle, a water circuit and a three-way valve (12). The refrigerating cycle is constituted by sequentially connecting, with use of piping, a compressor (1), a four-way valve (2) for switching the flow direction of a coolant, a water heat exchanger (3) for causing the coolant and the water to exchange heat, an expansion valve (4) for adjusting the flow rate of the coolant thereby lowering the pressure, and an air heat exchanger (5) for causing the air and the coolant to exchange the heat. The water circuit is constituted by sequentially connecting the water heat exchanger (3), a hot water tank (7) for reserving the water heated by the water heat exchanger (3), and a pump (11). The three-way valve (12) is so interposed between the pump (11) and the water heat exchanger (3) that the water circuit may flow to an air heat exchanger lower-stage path (5a) and may return to the water heat exchanger (3). Further comprised is a control unit for switching the three-way valve (12) of the water circuit, thereby causing the hot water in the hot water tank to flow to the air heat exchanger lower-stage path (5a).

Description

Heat pump water heater

The present invention relates to a heat pump type water heater employing a reverse type defrost system.

In a conventional heat pump water heater that uses a reverse type defrost system, the drain water dripped from the surface of the evaporator by the defrosting operation function under the temperature conditions at low outside temperatures freezes and grows on the drain pan. A method has been proposed in which a part of the high-pressure side refrigerant pipe of the heat pump cycle or a part of the hot water supply water pipe is arranged on the drain pan (see, for example, Patent Document 1).

JP 2004-218861 A (page 3 to page 4, FIG. 2, FIG. 4 to FIG. 5)

However, in the conventional heat pump type hot water heater drain pan freezing prevention method, a part of the high-pressure side refrigerant pipe and a part of the hot water supply water pipe may be placed in close contact with each other on the drain pan in order to efficiently transfer heat. Although important, there is a problem that the mounting structure of the refrigerant pipe and the water pipe is complicated. In addition, because part of the high-pressure side refrigerant pipe and part of the hot water supply water pipe are routed on the drain pan, the drain water drainage path generated during defrost operation is hindered by the routed refrigerant pipe and water pipe. There is a problem that drain accumulation may occur due to the difficulty of securing the gradient of the water distribution route.

The present invention has been made to solve such problems, and a first object of the present invention is to obtain a heat pump type water heater having a drain pan freeze prevention system having a simple structure with a small number of parts.
The second object of the present invention is to obtain a heat pump type water heater provided with a drain pan freezing prevention system in which drain accumulation is unlikely to occur without obstructing the drainage path of drain water generated during defrost operation.

The heat pump water heater according to the present invention includes a compressor, a four-way valve that switches the flow direction of the refrigerant, a water heat exchanger that exchanges heat between the refrigerant and water, an expansion mechanism that adjusts the flow rate of the refrigerant and depressurizes, and the air and the refrigerant are heated. A refrigeration cycle in which air heat exchangers to be replaced are sequentially connected in a ring, a water heat exchanger, a hot water storage tank for storing water heated by the water heat exchanger, and a water circuit in which pumps are connected in a ring in a sequential manner , A water flow pipe provided in the lower stage of the air heat exchanger, a path switching valve provided in a water circuit between the pump and the water heat exchanger, and a connection between the path switching valve and the inlet of the water flow pipe A bypass circuit formed by connecting the outlet of the water passage pipe to a water circuit between the path switching valve and the inlet of the water heat exchanger, and a control unit that switches and controls the four-way valve and the path switching valve, The control unit is based on preset information during defrost operation. The four-way valve is switched to switch the flow direction of the refrigerant in the refrigeration cycle, and the path switching valve is switched to allow hot water in the hot water storage tank to flow to the water flow pipe of the air heat exchanger via the bypass circuit. .

In the heat pump type water heater according to the present invention, the hot circulating water in the hot water storage tank is circulated to the lower path of the air heat exchanger during the defrost operation, and the drain water generated in the upper stage of the air heat exchanger is heated and poured into the drain pan. Thus, the drain pan is prevented from freezing, and there is an effect that the mounting structure is simplified without arranging a part of the high-pressure side refrigerant pipe or a part of the hot water supply water pipe on the drain pan.
In addition, because part of the high-pressure side refrigerant pipe and part of the hot water supply water pipe are not arranged on the drain pan, the drain water does not obstruct the drain water drainage path and the drain water drainage is smooth. Therefore, there is an effect of suppressing that the drain water in the drain pool is cooled and frozen during the heating operation.

It is a circuit diagram at the time of the defrost operation | movement of the heat pump type water heater which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure regarding control of the driving | operation of the heat pump type water heater which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the control part regarding control of the driving | operation of the heat pump type water heater which concerns on Embodiment 1 of this invention (the 1). It is a flowchart which shows operation | movement of the control part regarding control of the driving | operation of the heat pump type water heater which concerns on Embodiment 2 of this invention (the 2). It is a disassembled perspective view of the heat pump type water heater which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram at the time of defrosting operation of the heat pump type water heater according to Embodiment 1 of the present invention.
As shown in FIG. 1, the heat pump type water heater according to Embodiment 1 of the present invention includes a compressor 1, a four-way valve 2 for switching a refrigerant circuit during defrost operation, and water heat exchange in which water and refrigerant exchange heat. The apparatus 3 includes an electronic expansion valve 4 that adjusts the flow rate of the refrigerant and depressurizes, and an air heat exchanger 5 that exchanges heat between the air and the refrigerant through a refrigerant pipe 6 in order.
A water circuit 10 between the water heat exchanger 3 and the hot water storage tank 7 is connected by a water outlet side connection joint 8 and a water inlet side connection joint 9, and water is circulated by a pump 11. Between the water inlet side connection joint 9 and the water heat exchanger 3, the water circuit is connected to the water heat exchanger 3 during heating operation, and to the water heat exchanger 3 via the air heat exchanger lower path 5a during defrost operation. A three-way valve 12 for switching to 10 is provided. The three-way valve 12 constitutes a path switching valve. The air heat exchanger lower stage path 5a constitutes a water flow path pipe. The three-way valve 12 (path switching valve) is connected to the inlet of the air heat exchanger lower stage path 5a (water channel pipe), and the outlet of the air heat exchanger lower stage path 5a (water channel pipe) is connected to the three-way valve 12 A bypass circuit 14 is configured by connecting to the water circuit 10 between the (path switching valve) and the inlet of the water heat exchanger 3.
Moreover, the thick arrow in FIG. 1 has shown the direction through which water (or hot water) flows, and the broken line has shown the direction through which a refrigerant | coolant flows.
FIG. 2 is a block diagram showing a configuration relating to control of operation of the heat pump type water heater according to Embodiment 1 of the present invention.
In FIG. 2, reference numeral 21 denotes a control unit, which is constituted by a microcomputer, a DSP, or the like. A memory 22 stores various data and tables. Reference numeral 23 denotes a ROM that stores programs executed by the control unit 21 and fixed data. Reference numeral 24 denotes an input / output bus, and information on all devices is exchanged with the control unit 21 via the input / output bus 24.
Reference numeral 25 denotes a four-way valve drive unit that drives switching of the four-way valve 2 based on a command from the control unit 24. Reference numeral 26 denotes a three-way valve drive unit that drives switching of the three-way valve 12 based on a command from the control unit 24. A communication unit 27 receives setting information from a remote controller (hereinafter also referred to as a remote controller) 28 and sends the setting information to the control unit via the input / output bus 24.
The air heat exchanger lower stage path 5a constitutes a water passage pipe.

Next, the operation of the first embodiment will be described.
FIG. 3 is a flowchart showing the operation of the control unit 21 relating to the control of the operation of the heat pump type water heater according to Embodiment 1 of the present invention. Next, the operation of the control unit 21 in the first embodiment will be described with reference to FIGS.
While the power switch of the water heater is turned on, the operation of the water heater is executed, but this is not described here because it is irrelevant to the present application. During the operation of the water heater, the processing shown in FIG. 3 is periodically started with a relatively short cycle (for example, a cycle of several milliseconds to several seconds). When the processing of FIG. 3 is started, the control unit 21 performs initial value setting such as clearing of the timer value (step S301), and then receives from the remote controller 28 (step S302). Next, the control unit 21 examines the content received from the remote controller 28 and determines whether or not there is a defrost operation start command (step S303).
When the heat pump type water heater is operated at a low outside air temperature, the air heat exchanger 5 that exchanges heat between the air acting as an evaporator and the refrigerant has a low temperature of 0 ° C. or lower, and the air that passes through the air heat exchanger 5 Is cooled, moisture in the air is solidified on the surface of the air heat exchanger 5 to become frost and block the air passage. In order to ensure that the performance of the air heat exchanger 5 is favorable, a movement to remove frost attached to the surface of the air heat exchanger 5 is required, and it is necessary to perform a defrost operation. In the defrost operation, when the defrost operation start command signal is transmitted from the remote controller 28 based on the operation of the remote controller by the user, and the control unit 21 receives this command via the communication unit 27 and the input / output bus 24 in sequence, The unit 21 recognizes that the defrosting operation is started by this command signal, and controls the four-way valve driving unit 25 and the three-way valve driving unit 26 based on the defrosting operation information set in the memory 22 in advance. The three-way valve 12 is switched (steps S304 to S305). And the control part 21 drives the compressor 1, and starts a defrost driving | operation (step S306). At the same time, the timer is counted and the defrost operation is continuously executed until a predetermined time elapses (steps S307 to S308). By this defrost operation, the frost attached to the surface of the air heat exchanger is warmed, becomes drain water, falls on the drain pan 13 while being transmitted through the fins, flows through the drain groove of the drain pan 13 and is drained from the drain port to the outside of the machine. When the predetermined time has elapsed, the control unit 21 switches based on the four-way valve 2 and the three-way valve 12, further stops the compressor and stops the defrost operation (step S309), and ends the process. Thereafter, the water heater is operated.

As described above, by switching the three-way valve 12 during the defrost operation and flowing the high-temperature water supplied from the hot water storage tank 7 to the air heat exchanger lower path 5a, the drain water flowing down the fins is moved to the lower stage of the air heat exchanger 5. It is possible to prevent the drain water from freezing on the drain pan 13 by heating with
In the above example, the case where the defrost operation is instructed by the remote controller 28 has been described, but it is needless to say that the instruction may be performed by operating the switch on the operation panel on the main body side of the water heater.
In addition, when the control unit 21 calculates the operating efficiency of the heat pump type hot water heater and becomes lower than the predetermined operating efficiency, or when the temperature of the hot water in the hot water heater does not rise above the predetermined temperature, the defrost operation is performed. It may be configured to start automatically.
Next, the operation of the control unit 21 in such a case will be described.
FIG. 4 is a flowchart showing the operation of the control unit regarding the control of the operation of the heat pump type hot water heater according to Embodiment 2 of the present invention. 4 is the same as the flow in FIG. 3 except that steps S301 to S302 in FIG. 3 are replaced with steps S401 to S402.
Next, operation | movement of the control part 21 is demonstrated using FIG.
After the initial value setting (step S301), the control unit 21 calculates the operating efficiency of the heat pump water heater (step S401). A known method is used as a method for calculating the operating efficiency. For example, the operating efficiency is calculated based on the rotational speed of the compressor 1. The rotation speed of the compressor 1 is detected by attaching a rotation detector (not shown) to the rotation shaft of the compressor 1. Or you may calculate the rotation speed of the compressor 1 based on the output of the inverter output current detector which is not illustrated using the current detector (current transformer etc.) which is not illustrated.
Next, the control unit 21 compares the calculated driving efficiency with a preset reference value (step S402). If the operation efficiency is equal to or higher than the reference value, the process returns to step S401 to repeat the calculation of the operation efficiency and the comparison with the reference value. In the comparison in step S402, when the operation efficiency falls below a preset reference value, the operation is performed in the same manner as in step S304 and subsequent steps in FIG.
Accordingly, since the defrost operation is automatically performed, the user does not need to perform an operation for instructing the defrost operation. In addition, since the defrost operation is surely executed, efficient operation is always possible.

Embodiment 2. FIG.
FIG. 5 is an exploded perspective view of a heat pump type water heater according to Embodiment 2 of the present invention.

The water heat exchanger 3, the air heat exchanger lower-stage path 5 a, and the water inlet side connection joint 9 are provided in the vicinity of the three-way valve 12 used for switching the water circuit during the defrost operation. It is possible to reduce the manufacturing cost by shortening the pipe length and making the structure simple.

Further, by providing the three-way valve 12 used for switching the water circuit during the defrost operation on the inlet side of the water heat exchanger 3, the high temperature circulated from the hot water storage tank 7 in the water heat exchanger 3 as an evaporator during the defrost operation. It becomes possible to supply the air heat exchanger to the lower stage path 5a without lowering the temperature of the water.

Further, in the fins provided in the air heat exchanger 5, the fins in the path portion through which the refrigerant flows are eliminated from cutting, so that the fins around the path portion where the low-temperature refrigerant flows and becomes an evaporator during heating operation. Since it improves, it is possible to suppress the growth of frost.

1 compressor, 2 way valve, 3 water heat exchanger, 4 electronic expansion valve, 5 air heat exchanger, 5a air heat exchanger lower stage path, 6 refrigerant piping, 7 hot water storage tank, 8 water outlet side connection joint, 9 water Inlet connection joint, 10 water circuit, 11 pump, 12 three-way valve, 13 drain pan, 14 bypass circuit, 21 control unit, 22 memory, 23 ROM, 24 I / O bus, 25 four-way valve drive unit, 26 three-way valve drive unit, 27 Communication section, 28 Remote controller.

Claims

A compressor, a four-way valve that switches the flow direction of the refrigerant, a water heat exchanger that exchanges heat between the refrigerant and water, an expansion mechanism that adjusts the flow rate of the refrigerant and depressurizes, and an air heat exchanger that exchanges heat between the air and the refrigerant are sequentially piped A refrigeration cycle connected in a ring with
The water heat exchanger, a hot water storage tank for storing water heated by the water heat exchanger, and a water circuit in which pumps are sequentially connected in an annular shape by piping;
A water passage pipe provided in a lower stage of the air heat exchanger;
A path switching valve provided in a water circuit between the pump and the water heat exchanger;
A bypass circuit connected between the path switching valve and the inlet of the water flow path pipe, and connecting an outlet of the water flow path pipe to a water circuit between the path switching valve and the inlet of the water heat exchanger When,
A control unit for switching and controlling the four-way valve and the path switching valve,
In the defrost operation, the control unit switches the four-way valve based on preset information to switch the refrigerant flow direction of the refrigeration cycle, and switches the path switching valve to supply hot water in the hot water storage tank. A heat pump type hot water heater which is caused to flow through the bypass circuit to the water flow pipe of the air heat exchanger.
The drain pan which collects the drain water which was heated by the water flow-path piping of the said air heat exchanger, and fell from the said air heat exchanger below the said air heat exchanger is characterized by the above-mentioned. Heat pump water heater.
The heat pump type hot water heater according to claim 1 or 2, wherein the fin of the water flow path piping portion of the air heat exchanger is not cut and raised.
The water heat exchanger, the water flow pipe of the air heat exchanger, and the water inlet side circuit connection joint are provided in the vicinity of the path switching valve. Heat pump type water heater.
The heat pump type water heater according to any one of claims 1 to 4, wherein the path switching valve is provided on an inlet side of the water heat exchanger.
The heat pump type water heater according to any one of claims 1 to 5, wherein the path switching valve is a three-way valve.
The heat pump type water heater according to any one of claims 1 to 6, wherein the control unit executes a defrost operation based on a command from a user.
The heat pump hot water heater according to any one of claims 1 to 6, wherein the control unit executes a defrost operation when the efficiency falls below a preset reference value.