Defrost control method of air source heat pump system

Abstract

The invention relates to a defrost control method of an air source heat pump system, and relates to the technical field of air conditioning refrigeration and heat pumps. The defrost control method comprises the steps of when a system runs and one unit reaches to a defrost condition, naming the unit as a unit a, and carrying out the following judgment: (i) when no unit is at a standby mode, enabling the unit a to enter a normal defrost mode; (ii) when the other unit is at a standby mode, naming the unit as a unit b; if the state of the unit b is not 'to be defrosted', closing the unit a, enabling the unit a to enter the standby mode, and meanwhile, enabling the unit b to start heating for running; and otherwise, keeping the unit a to be at a heating mode, and then carrying out correspondingcontrol; and (iii) when two and more that two units are at the standby mode, judging and selecting the units, naming the selected units as units b, and carrying out follow-up control according to thestep as shown in (ii). The method provided by the invention can be used for carrying out defrost control on a multiple air source heat pump unit combined operation system, and effectively solves various problems caused by defrosting of a current air source heat pump system through adjusting a defrost control logic.

Description

technical field [0001] The invention relates to the technical fields of air-conditioning refrigeration and heat pumps, in particular to a defrosting control method for an air source heat pump system. Background technique [0002] With the promotion of a series of policies such as energy saving, emission reduction, and atmospheric governance, air source heat pumps have gradually been recognized as a clean and energy-saving heating method, and have achieved considerable development in recent years. Defrost has always been one of the key technologies of air source heat pumps, and it is also a difficulty that hinders the performance improvement of air source heat pumps and restricts its promotion. In the prior art, the mainstream defrosting methods of air source heat pump units include reverse defrosting and hot gas bypass defrosting. During the heating operation of the unit, when the detection reaches the defrosting condition, it will enter the defrosting mode, and turn on the...

AI Technical Summary

Problems solved by technology

[0003] 1) The heating of the unit is suspended during defrosting, and the reverse defrosting will also take heat from the evaporator, resulting in a drop in water temperature and room temperature, affecting indoor temperature control

[0004] 2) The defrosting process consumes more electric energy, which reduces the overall energy efficiency of the heat pump

[0005] 3) During the defrosting process, valve switching, fluid reversal, and drastic changes in system pressure and temperature all cause impacts on various components of the system, and are not conducive to the normal oil return of the compressor, shortening the overall life of the unit

It also creates additional noise, exacerbating the noise problem with air source heat pumps

[0006] 4) Due to the variable outdoor environment and building load, uneven frosting, sensor interference and other factors, the current air source heat pump defrosting technology level cannot fully achieve accurate defrosting

As a result, it is very common for air source heat pumps to defrost without frost, which exacerbates the aforementioned three problems.