Frost-less air-source heat pump hot water unit and proportional-integral-differential control method for same

Abstract

The invention discloses a frost-less air-source heat pump hot water unit and a proportional-integral-differential control method for the same. The proportional-integral-differential control method includes performing computation according to received air temperature and humidity parameters, received air pressure parameters and received surface temperature parameters of an evaporator when outdoor temperature parameters which are transmitted by a temperature and humidity sensor and are received by a computation controller are lower than 0 DEG C, controlling the opening of an electronic expansion valve according to a computation result and regulating the surface temperature of the evaporator by means of increasing or reducing the opening of the electronic expansion valve so that the surface temperature of the evaporator is constantly higher than a frost formation point; and enabling a silicon-controlled power regulator to judge a suction superheat degree of a compressor according to received suction temperature and suction pressure of the compressor, increasing or reducing the power of an electric heater and maintaining that the suction superheat degree of the compressor only varies within a set value range. The frost-less air-source heat pump hot water unit and the proportional-integral-differential control method have the advantage that adjustment for the opening of the electronic expansion valve is matched with adjustment for the power of the electronic heater, so that the purpose of maintaining safe and efficient running of a system is achieved.

Description

technical field [0001] The invention belongs to the field of air conditioning, and relates to a frost-free air source heat pump water heater unit and a proportional-integral-differential control method thereof. Background technique [0002] An air source heat pump is an air-conditioning device that uses air as a cold and heat source, and can both cool water and make hot water. The unit saves a set of complex cooling water system and boiler heating system, which is easy to install and use, and has a wide range of applications. However, the air source heat pump has two obvious defects when it operates in winter heating conditions. First, the heating capacity and COP decrease rapidly with the decrease of outdoor air temperature. This problem is not enough to shake the position of air source heat pumps. First, the reduction of heating capacity can be prevented by selecting units with larger capacity. Second, the outdoor temperature in southern China is generally average in wint...

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Problems solved by technology

[0006] Technical problem: In view of the shortcomings of the existing air source heat pumps such as low operating efficiency, frosting in winter heating conditions, and short system life, the present invention provides a heat pump with high operating efficiency, accurate monitoring and control, and continuous operation in low temperature and humid environments. , the power of the electric heater can be adjusted according to the outdoor weather conditions to reduce energy consumption, which can ensure the safe operation of the compressor and the long-life frost-free air source heat pump water heater unit, and also provides a proportional-integral-derivative control of the unit method

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