JPH05288407A - Heat pump type hot water feeding device - Google Patents

Abstract

PURPOSE:To prevent a reduction of hot water temperature within a hot water storing tank during a transition period in which a heat pump cycle reaches its stable state when a defrosting operation is carried out and after the defrosting operation is completed in a hot water storing type heat pump type hot water feeding device. CONSTITUTION:A compressor 1 of a heat pump cycle is provided with a discharging pressure sensor 16, and an evaporator 6 is provided with a frosting sensor 14. A controller for use in controlling a pump 8 and a four-way valve 2 in response to signals from each of the sensors 14, 16 are provided. When the frosting sensor 14 is operated, the pump 8 is stopped and at the same time the four-way valve 2 is changed-over to that for the defrosting operation. After completion of the defrosting operation, the four-way valve is changed over to that for the operation of the heat pump and when the pressure of the discharging pressure sensor 16 reaches the predetermined value, the pump 8 is driven. The hot water of lower temperature than the hot water temperature within the hot water storing tank during the defrosting operation is prevented from flowing into the hot water storing tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water storage type heat pump water heater.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional heat pump water heater comprises a compressor 1, a four-way valve 2, a heat exchanger 3 for hot water, and a throttle mechanism 5 provided with a check valve 4 in parallel and an evaporator 6. A heat pump cycle formed by coupling with an annular refrigerant pipe, a water supply circuit 9 from the lowermost portion of the hot water storage tank 7 to the heat exchanger 3 for hot water via the pump 8, and the heat exchanger 3 for hot water to the hot water storage tank 7 The heat pump cycle and the hot water storage tank 7 are connected to each other by a hot water supply circuit 11 that reaches the hot water outlet pipe 10 provided at the top of the above. Further, 12 is a water temperature detector for detecting the water temperature in the hot water supply circuit 11, 13 is a frosting detector provided in the evaporator 6, 14 is a blower, and 15 is a water supply pipe provided in the hot water tank 7.

In the above structure, the operation of the heat pump cycle will be described first. The high-temperature and high-pressure gas refrigerant compressed by the compressor 1 enters the hot water heat exchanger 3 through the four-way valve 2. The gas refrigerant in the heat exchanger 3 for hot water exchanges heat with the water sent from the hot water storage tank 7 through the water supply circuit 9 and the pump 8, and gives heat to the water to condense to become a liquid refrigerant. After that, it enters the throttling mechanism 5, is decompressed, and takes heat from the outside air sucked by the blower 14 in the evaporator 6 to evaporate and become a gas refrigerant. The gas refrigerant returns to the compressor 1.

Next, the operation of the water circuit will be explained.
The water is sent from the lowermost part of the pump to the hot water heat exchanger 3 through the water supply circuit 9 to exchange heat with the high-temperature and high-pressure gas refrigerant to heat the water.

Hot water passes through the hot water supply circuit 11 and the hot water supply pipe 10,
It flows into the upper part of the hot water storage tank 7, and the hot water is sequentially stored from the upper part. Here, the rotation speed of the pump 8 is controlled by the water temperature detector 12 to keep the hot water temperature at the outlet of the hot water heat exchanger 3 constant. Further, when the evaporator 6 is frosted during the operation of the device in winter, the frost detector 13 switches the four-way valve 2 as shown by the dotted line in the figure, and the gas refrigerant enters the evaporator 6 for defrosting and the check valve. The heat exchanger 3 for hot water enters from 4. At this time, the pump 8 is operated, and the hot water heat exchanger 3 functions as an evaporator. The refrigerant evaporated in the hot water heat exchanger 3 returns to the compressor 1. When the defrosting ends, the frost detector 13 switches the four-way valve 2 to return to the normal cycle.

[0006]

However, in the above-mentioned conventional configuration, when the pump 8 is operated during the defrosting operation, the heat exchanger 3 for hot water acts as an evaporator, so that the low temperature in the hot water storage tank 7 is reduced. The water becomes cooler and the hot water supply circuit 1
Since it flows through 1 to the hot water outlet pipe 10, it mixes with the hot water stored in the hot water storage tank 7 to lower the hot water temperature. Since the pump 8 is operated until the heat pump cycle reaches a stable state (until the outlet water temperature of the hot water heat exchanger 3 reaches a predetermined value) after defrosting, the temperature is lower than the hot water temperature in the hot water storage tank 7. There is a problem that the hot water having a temperature flows into the hot water storage tank 7 and is mixed with the hot water stored in the hot water storage tank 7 as in the defrosting operation to lower the hot water temperature.

The present invention solves the above problems, and an object thereof is to prevent the temperature of hot water in the hot water storage tank 7 from decreasing during the defrosting operation and during the transition from the completion of the defrosting until the heat pump cycle reaches a stable state. It was done.

[0008]

In order to achieve the above object, the present invention provides a compressor with a discharge pressure detector and an evaporator with a frost detector, and controls the four-way valve and pump by each detector. It is configured to have a controller.

[0009]

According to the present invention, when the frost detector operates, the present invention stops the pump and switches the four-way valve to defrost the evaporator, and after defrosting, switches the four-way valve to discharge the compressor pressure. When the pressure detected by the detector reaches a predetermined value, the pump is driven to reduce the temperature of the hot water in the hot water tank 7 during the defrosting operation and during the transient period until the heat pump cycle reaches a stable state after the defrosting is completed. It can be prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, the same reference numerals as those in FIG. 3 denote the same members and have the same functions, so that the detailed description will be omitted and different points will be mainly described.

In FIG. 1, reference numeral 16 is a discharge pressure detector for detecting the discharge pressure of the compressor 1, and 17 is a discharge pressure detector 16,
The pump 8 is generated by the signals from the detectors of the frost formation detector 13,
It is a controller that controls the four-way valve 2.

The operation of the above configuration will be described with reference to the control flow of FIG. The defrosting operation operation during device operation will be described with reference to FIG. 2. First, the frost detector 14 determines whether or not the evaporator 6 is frosted, and if it is not frosted, the four-way valve 2 is closed (see FIG. 1 solid line) The pump 8 is in a normal operating state. On the contrary, if frost is formed, the four-way valve 2 is opened by the frost detector 13 (dotted line in FIG. 1), the pump 8 is stopped, and the defrosting operation operation for thawing the frost adhering to the evaporator 6 is started.
When the frost attached to the evaporator 6 is completely defrosted by the defrosting operation, the frost detector 13 causes the four-way valve 2 to be in the closed state (solid line in FIG. 1) to return to normal operation, but the discharge pressure of the compressor 1 is reduced. Pump 8 until the pressure detected by detector 16 reaches a predetermined value
Does not drive. When the detected pressure reaches a predetermined value, the pump 8 enters the normal operation state. The controller 17 performs the above operation.

According to the configuration of this embodiment, the pump 8 is stopped during the defrosting operation of the evaporator and during the transient period after the defrosting until the heat pump cycle reaches a stable state.
By preventing hot water having a temperature lower than the hot water temperature in the hot water storage tank 7 from flowing into the hot water storage tank 7, there is an effect of preventing a decrease in the hot water temperature in the hot water storage tank 7.

In this embodiment, the pump 8 is driven by the pressure detected by the discharge pressure detector 16 of the compressor 1. Instead of the discharge pressure detector 16, the outlet water temperature of the hot water heat exchanger 3 is used. The same effect can be obtained even if the pump 8 is detected and driven.

[0016]

As described above, in the heat pump hot water supply apparatus of the present invention, the compressor is provided with the discharge pressure detector and the evaporator is provided with the frost detector, and the water is circulated in the hot water tank when the frost detector is activated. The controller that stops the pump and switches the four-way valve to the defrosting side, switches the four-way valve to the heat pump operating side after defrosting, and drives the pump when the pressure of the discharge pressure detector reaches a predetermined value. Is provided,
When frost is formed on the evaporator, the controller that receives the signal from the frost detector stops the pump and switches the four-way valve to defrost the evaporator, and after defrosting, the four-way valve is put into heat pump operation. The hot water temperature in the hot water tank during switching and when the pressure detected by the discharge pressure detector reaches a predetermined value, the pump is driven to perform defrosting operation, and during the transient period until the heat pump cycle after defrosting reaches a stable state The hot water having a lower temperature is prevented from flowing into the hot water storage tank, and the temperature drop of the hot water in the hot water storage tank is prevented.

The same effect can be obtained by driving the pump by detecting the outlet water temperature of the hot water heat exchanger instead of driving the pump by the pressure detected by the discharge pressure detector of the compressor.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a heat pump water heater according to an embodiment of the present invention.

FIG. 2 is a control flowchart for the defrosting operation of FIG.

FIG. 3 is a circuit configuration diagram of a conventional heat pump water heater.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Heat exchanger for hot water 4 Check valve 5 Throttling mechanism 6 Evaporator 7 Hot water storage tank 8 Pump 9 Water supply circuit 11 Hot water supply circuit 13 Frost detector 16 Discharge pressure detector 17 Controller

Claims (1)

[Claims] 1. A compressor, a four-way valve, a heat exchanger for hot water, a throttle mechanism provided with check valves in parallel, a heat pump formed by connecting an evaporator with an annular refrigerant pipe, and a bottom portion of a hot water storage tank. A water supply circuit leading to a hot water heat exchanger via a pump, a hot water supply circuit leading from the hot water heat exchanger to a hot water outlet pipe provided at the top of the hot water storage tank, a discharge pressure detector provided in the compressor, and an evaporator. When the frost detector installed in the device and the frost detector are activated, the pump is stopped and the four-way valve is switched to the defrosting operation side, and after the defrosting is completed, the four-way valve is switched to the heat pump operation side and the discharge is performed. A heat pump water heater provided with a controller that drives a pump when the pressure of the pressure detector reaches a predetermined value.