JP2007057148A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect a decrease in heating ability by using a temperature detecting means installed at the entrance of an evaporator. <P>SOLUTION: The temperature detecting means installed at the entrance of the evaporator is used to enhance the accuracy of detecting a decrease in the heating ability and to prevent malfunctions due to frost growth. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a defrosting operation of a heat pump water heater having a compressor, a hot water supply heat exchanger, an expansion valve, and a heat pump circuit in which an evaporator is connected by a pipe, a hot water tank, and a fluid circuit in which a fluid circulation pump is connected by the pipe. About.

In the conventional technology, when two sensors for detecting the temperature of the evaporator are installed, the temperature detection means usually installed at the outlet of the evaporator is used to determine the start of the defrosting operation. Start frost operation. It has been proposed to determine the end of the defrosting operation using the temperature detection means installed at the outlet of the evaporator even after the start of the defrosting operation (see, for example, Patent Document 1).
JP-A-2005-147609

  However, in the conventional configuration, when the heating capacity is reduced due to a decrease in the suction pressure of the evaporator due to frost formation or the like, the temperature detection installed at the outlet of the evaporator when the gas shortage or the path balance of the evaporator is broken There is a problem that it is difficult for the means to accurately detect a decrease in heating capacity. SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to accurately detect a decrease in heating capacity using a temperature detection means installed at the inlet of an evaporator.

  In order to solve the conventional problems, a heat pump type hot water supply apparatus of the present invention includes a heat pump circuit in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, a hot water storage tank, a fluid circulation pump, A heat pump hot water supply apparatus having a circulation circuit in which a heat exchanger for hot water supply is connected by piping, using a temperature detection means installed at the inlet of the evaporator to determine the defrosting operation start condition, After reducing the flow rate, the opening of the expansion valve is opened.

  In addition, after the start of the defrosting operation, the end condition of the defrosting operation is determined by using the temperature detection means installed at the outlet of the evaporator, and the defrosting operation is ended.

  The heat pump type hot water supply apparatus of the present invention uses the temperature detection means installed at the inlet of the evaporator for the condition determination for starting the defrosting operation, thereby improving the accuracy of detecting a decrease in heating capacity and the function due to the growth of frost. Failure can be prevented. Moreover, the accuracy of detecting a frosting state can be improved and function recovery can be performed smoothly by using the temperature detection means installed at the outlet of the evaporator for determining whether the defrosting operation has ended.

  A first invention includes a heat pump circuit in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, and a circulation circuit in which a hot water tank, a fluid circulation pump, and a hot water heat exchanger are connected by piping. The heat pump hot water supply device has a temperature detection means installed at the inlet of the evaporator to determine the defrosting operation start condition, and after reducing the flow rate of the fluid circulation pump, the opening of the expansion valve By opening, it is possible to improve the accuracy of detecting a decrease in heating capacity and prevent malfunction due to frost growth.

2nd invention determines the completion | finish conditions of defrost operation using the temperature detection means installed in the exit of an evaporator after the defrost operation start started by the determination method of 1st invention, and performs defrost operation. By ending, the accuracy of detecting the frosting state can be improved, and the function recovery can be performed smoothly.

(Embodiment 1)
1-3 show the heat pump hot-water supply apparatus and operation control in Embodiment 1 of this invention.

  FIG. 1 shows a heat pump cycle constituted by connecting an inverter type compressor 11, a hot water supply heat exchanger 12, a pressure reducing device 13, and an evaporator 14 in an annular shape by a refrigerant pipe 15, and a hot water storage tank 16 for storing hot water supply liquid. A liquid pipe 18 through which the liquid in the hot water tank can circulate through the hot water supply device, a pump 17 for circulating the liquid in the hot water tank through the liquid pipe, and temperature detection means installed at the inlet of the evaporator 14 21, temperature detecting means 22 installed at the outlet of the evaporator 14, and a microcomputer 30 for controlling the rotational speed of the pump.

  FIG. 2 is a configuration diagram of the conventional operation control. The defrosting operation start condition calculation 31 is performed using the temperature detection means 22 installed at the outlet of the evaporator 14, and the defrosting operation start determination 32 is performed. The operation control which performs 34 is provided.

  Next, the operation of this embodiment will be described. 3 performs the defrosting operation start condition calculation 31 using the temperature detection means 23 installed at the inlet of the evaporator 14 with the configuration of FIG. 1, and starts the defrosting operation 34 by the defrosting operation start determination 32. By having control, the precision which detects the fall of a heating capability can be improved, and the malfunction by the growth of frost can be prevented. Therefore, it is possible to continue the operation without deteriorating the function as a heat pump hot water supply device such as running out of hot water.

(Embodiment 2)
After starting the defrosting operation started by the determination method in Embodiment 1, using the temperature detection means installed at the outlet of the evaporator to determine the end condition of the defrosting operation, by ending the defrosting operation, It is possible to improve the accuracy of detecting the frosting state and smoothly perform the function recovery. Therefore, the operation can be continued without impairing the function of the heat pump hot water supply device such as running out of hot water after the completion of the defrosting operation.

Embodiment 1 System Configuration Block Diagram of the Present Invention Flowchart of algorithm in Embodiment 1 of the present invention Conventional algorithm flow chart

Explanation of symbols

11 Inverter compressor 12 Hot water supply heat exchanger 13 Pressure reducing device (electric expansion valve)
14 Evaporator 15 Refrigerant Piping 16 Hot Water Tank 17 Pump (Water Pump)
DESCRIPTION OF SYMBOLS 18 Liquid piping 19 Fan 20 Fan motor 21 Evaporator inlet temperature sensor 22 Evaporator outlet temperature sensor 30 Microcomputer 31 Calculation means using evaporator outlet temperature detection means 32 Defrosting operation start determination 33 Normal operation 34 Defrosting operation 35 Evaporation Calculation means using evaporator outlet temperature detection means 36 Determination of completion of defrosting operation 37 Calculation means using evaporator inlet temperature detection means

Claims (2)

A heat pump water heater having a heat pump circuit in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, a hot water storage tank, a fluid circulation pump, and a circulation circuit in which the hot water heat exchanger is connected by piping The temperature detecting means installed at the inlet of the evaporator determines the defrosting operation start condition, reduces the flow rate of the fluid circulation pump, and then opens the opening of the expansion valve. Heat pump water heater. The heat pump hot-water supply device according to claim 1, wherein after the defrosting operation is started, a defrosting operation end condition is determined by temperature detection means installed at an outlet of the evaporator, and the defrosting operation is ended.

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