Frequency adjusting and control method for variable-frequency enhanced vapor injection heat-pump water heater

Abstract

The invention relates to a frequency adjusting and control method for a variable-frequency enhanced vapor injection heat-pump water heater. The frequency adjusting and control method is characterized by comprising the adjusting steps that a, when a user selects a fast mode, the heat-pump water heater detects outdoor environment temperature T1 and the actual temperature T2 of a water tank, and the frequency of a compressor is adjusted with the actual temperature T2 of the water tank as a feedback object; b, when the user selects an energy saving mode, a controller detects the current actual temperature T2 of the water tank, and the needed total quantity of heat production within water using time t is calculated; c, when the heat-pump water heater works according to the frequency adjusting method of the step a and the step b, the opening degree of a main electronic expansion valve and an auxiliary electronic expansion valve is adjusted with the optimum energy efficiency ratio according to the compressor frequency, the outdoor environment temperature T1 and the water tank actual temperature T2 obtained through the experiment; d, the highest frequency allowed by the heat-pump water heater can be determined through an experiment method, and is preset in the controller in a functional expression or list mode. The frequency adjusting and control method has the advantages that that the variable-frequency enhanced vapor injection heat-pump water heater is made to work at the frequency close to the optimum energy efficiency ratio frequency point as much as possible, the opening degree of the main electronic expansion valve and the auxiliary electronic expansion valve is controlled with the optimum energy efficiency ratio, and energy is saved.

Description

technical field [0001] The invention relates to a control method for a heat pump water heater, in particular to a frequency adjustment and control method for a heat pump water heater with variable frequency injection and enthalpy increase. Background technique [0002] Air injection enthalpy-increasing technology is an effective way to solve the heating capacity and energy efficiency ratio of air source heat pump water heaters in low-temperature environments. With the development of frequency conversion technology, frequency conversion air-injection enthalpy increasing heat pump water heaters have gradually begun to be used. At present, the compressor frequency adjustment method adopted by the frequency conversion air injection heat pump water heater uses the difference between the target temperature of the water tank and the instant temperature of the water tank as the feedback object. Run to increase heat production (heating operation) and shorten heating time. When the t...

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Problems solved by technology

from figure 1 The dynamic relation diagram of air source heat pump heat output, energy efficiency ratio and compressor frequency shows that the heat output of air source heat pump water heater increases with the increase of compressor frequency, but its energy efficiency ratio shows a parabolic trend. When the compressor frequency When the frequency is higher than a certain frequency, the energy efficiency ratio decreases with the increase of the compressor frequency, and when the frequency is lower than this frequency, the energy efficiency ratio decreases with the decrease of the compressor frequency. Obviously, in the current frequency adjustment method, the air source heat pump water heater is running at a higher temperature. The process far deviates from the best energy efficiency ratio frequency point, and in stable operation, it also deviates from the best energy efficiency ratio frequency point, so that the energy-saving advantages of frequency conversion technology cannot be fully utilized

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