Control method for defrosting of air energy heat pump judging dewpoint

Abstract

The invention discloses a control method for defrosting of an air energy heat pump judging a dewpoint. The control method includes the following steps that firstly, a defrosting judging period Dt is preset; secondly, a real-time dewpoint temperature T1 of the outside environment is judged, and temperature T2 of an evaporator coil pipe is detected; thirdly, if T2 is larger than 0 DEG C, a defrosting program of a set is not started; and if T2 is smaller than or equal to 0 DEG C, and delta t1 is delayed to start the defrosting program, wherein delta t1=k1 / (T1-T2); fourthly, when the temperature of the evaporator coil pipe reaches a set temperature T, defrosting of the set stops, wherein T is larger than 0 DEG C; fifthly, when the defrosting interval meets Dt, a real-time dewpoint temperatureT3 of the outside environment at the moment is judged again, temperature T4 of the evaporator coil pipe is acquired, and delayed correction time delta t2 is calculated, wherein delta t2=k2 / (T3-T4); and sixthly, after the defrosting interval is delayed by the set by delta t2, the steps from the first step to the fifth step are repeated, repeating is performed in this way, and defrosting control ismade to achieve an optimal effect.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a defrosting control method of an air energy heat pump for judging the dew point. Background technique [0002] Air energy water heaters, also known as heat pump water heaters, are heat transfer devices that use the heating principle to absorb heat from the air to produce hot water. It transfers the heat in the air to the water by allowing the medium to continuously complete the thermodynamic cycle process of evaporation (absorbing heat from the environment) → compression → condensation (release heat) → throttling → re-evaporation. When the air-cooled heat pump unit is running in winter, when the temperature of the outdoor heat exchanger coil is lower than the dew point temperature, condensed water will be generated on the surface, and once the condensed water is lower than 0°C (varies according to the regional atmospheric pressure value), frost will form . If the surf...

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Problems solved by technology

However, due to the two-way limitation of the running time of the compressor and the temperature of the outdoor heat exchanger coil, in this method, the unit should not defrost and enter the defrosting, and defrosting is required but the defrosting is postponed; if the air humidity is very high In a large environment, when the frost layer on the surface of the heat exchanger is very thick, which has seriously affected the air volume and heat exchange effect, and it is urgent to defrost, but the running time of the compressor has not reached the set time, the unit is still at a relatively low evaporation temperature It not only affects the heating effect of the unit, but also consumes a lot of energy. For example, in a low-temperature environment and the air moisture content is relatively small, even if there is no frost on the surface of the heat exchanger, when the running time of the compressor is up, it must enter the chemical state. Therefore, the normal heating operation time of the unit is greatly reduced, the energy consumption increases, and the heating effect is affected

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