Heat pump water heater and its control method

Abstract

The invention discloses a heat pump water heater. The heat pump water heater includes a compressor, an outdoor heat exchanger, a four-way valve and an indoor unit. The hot water outlet on the upper part of the shell; the water inlet of the thermosiphon is provided with a first temperature sensor, and the water outlet of the thermosiphon is provided with a second temperature sensor; the heat pump water heater also includes a controller, the controller is used for the first temperature sensor and the second temperature sensor When the difference between the temperatures detected by the two temperature sensors is smaller than the first preset threshold, the switching of the four-way valve is controlled so that the heat pump water heater enters the defrosting mode. The invention also discloses a control method of the heat pump water heater. In the present invention, it is only judged whether the heat pump water heater needs defrosting by the temperature of the water inlet and the water outlet of the thermosiphon in the indoor unit, and the defrosting control of the heat pump water heater is more accurate.

Description

technical field [0001] The invention relates to the technical field of water heaters, in particular to a heat pump water heater and a control method thereof. Background technique [0002] With the continuous improvement of people's living standards, the demand for hot water is also increasing. Traditional gas and electric water heaters will have safety hazards such as emitting harmful combustion products and easy leakage of electricity. At the same time, they consume high-quality water such as gas and electricity. Disadvantages of energy, air source heat pump water heater is a new type of water heater after gas water heater and electric water heater. The heat exchange pipeline performs heat exchange to heat the cold water in the indoor unit. After heat exchange, the low-temperature refrigerant flowing out of the indoor unit enters the outdoor heat exchanger and absorbs a large amount of heat from the air to increase the return air temperature and reduce power consumption. ,...

AI Technical Summary

Problems solved by technology

[0003] However, when the heat pump water heater is used in an environment with very low outdoor temperature in winter, the evaporation temperature of the refrigerant is very low, and the moisture in the air is easy to condense into frost on the surface of the outdoor heat exchanger, especially in areas with high air humidity. It is easy to appear, and frost will increase the wind resistance of the outdoor heat exchanger, resulting in a decrease in the heat transfer coefficient of the outdoor heat exchanger, which further reduces the heating efficiency of the heat pump water heater

In the prior art, a temperature sensor is installed in the outdoor heat exchanger to detect the temperature in the middle of the outdoor heat exchanger to determine whether to defrost, that is, when the temperature detected by the temperature sensor installed in the outdoor heat exchanger is lower than the preset temperature value, the control The heat pump water heater defrosts, but the temperature of the heat pump water heater is greatly affected by the external environment, resulting in inaccurate defrosting control of the heat pump water heater

Images