Gas supplementing and enthalpy increasing control method of low-temperature type direct-current variable-frequency heat pump system

Abstract

The invention discloses a gas supplementing and enthalpy increasing control method of a low-temperature type direct-current variable-frequency heat pump system. The key of the method is as follows, anexhaust temperature of the system is detected, when the exhaust temperature is larger than or equal to 70 DEG C, and when an exhaust superheat degree is larger than or equal to 25 DEG C, an enthalpyspraying electromagnetic valve (10) is electrified and started, and an enthalpy spraying auxiliary path is circulated; an enthalpy spraying electronic expansion valve (11) is started, an initial opening degree is 100 PLS and kept for 3 minutes, then adjusting is carried out according to an actual supercooling degree, when the actual supercooling degree is larger than or equal to a target supercooling degree, the opening valve control of the enthalpy spraying electronic expansion valve (11) is carried out; and when the actual supercooling degree is less than the target supercooling degree, theclosing valve control of the enthalpy spraying electronic expansion valve (11) is carried out, when the exhaust superheat degree is less than 20 DEG C, the enthalpy spraying electronic expansion valve(11) is closed, the enthalpy-spraying auxiliary path is not circulated, and the safety and reliability of a compressor are guaranteed. According to the gas supplementing and enthalpy increasing control method of the low-temperature direct-current variable-frequency heat pump system, the problems that in an actual application project, the heating performance of the variable-frequency heat pump system is attenuated and the system reliability is poor in a low-temperature use environment are solved.

Description

technical field [0001] The invention relates to the technical field of a low-temperature DC frequency conversion heat pump system, in particular to a method for controlling air supplementation and enthalpy increase of a low temperature DC frequency conversion heat pump system. Background technique [0002] The lower the outdoor temperature, the worse the heating effect of the air conditioner and the lower the energy efficiency ratio. In the case of heating, as the outdoor ambient temperature continues to drop, the indoor heat load continues to increase. At the same time, the suction specific volume of the refrigerant increases, the suction volume of the unit decreases, and the heating capacity of the system decreases, which cannot meet the indoor heat load. load demand. As the compression ratio of the compressor increases, the coefficient of performance of the system also drops sharply. [0003] In addition, the low pressure of the system decreases with the drop of the ext...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is: to provide a low-temperature direct current frequency conversion heat pump system air replenishment and enthalpy increase control method to solve the problem of attenuation of heating performance and system reliability of the frequency conversion heat pump system in the low temperature environment in practical application engineering

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