Defrosting control method in heating operation of variable frequency air conditioner

Abstract

The invention discloses a defrosting control method in a heating operation of a variable frequency air conditioner. The method comprises the steps of: recording temperature values of coils of all outdoor heat exchangers within a time period that the heating is preformed for 7-12 minutes, and selecting the lowest value as a standard temperature value Te0; when the operation is totally performed for 29-32 minutes, entering a defrosting process if two conditions are synchronously satisfied, wherein the condition 1 is that the temperature values Te of the coils of the outdoor heat exchangers at present are lower than -7 DEG C for 2 minutes continuously, and the condition 2 is that the temperature values Te of the coils of the outdoor heat exchangers at present are more than 5 DEG C lower than the standard temperature value Te0; and when the operation is totally performed for over 35 minutes, entering the defrosting process if two conditions are synchronously satisfied, wherein the condition 1 is that the temperature values Te of the coils of the outdoor heat exchangers at present are lower than -5 DEG C for 2 minutes continuously, and the condition 2 is that the temperature values Te of the coils of the outdoor heat exchangers at present are more than 4 DEG C lower than the standard temperature value Te0. The control method can precisely switch to a defrosting mode.

Description

technical field [0001] The invention relates to the field of frequency conversion air conditioners, in particular to a method for controlling defrosting during thermal operation of frequency conversion air conditioners. Background technique [0002] The defrosting process of the inverter air conditioner is very important in the heating process. Especially in winter, when the outdoor temperature is low and the humidity is high, the coils of the outdoor heat exchanger are prone to frost. If the frost is thick, it is easy to block the heat exchange channel between the outdoor heat exchanger and the air, seriously reducing the heat exchange effect of the outdoor heat exchanger. [0003] However, the defrosting technology in the prior art is generally to switch the direction of the four-way reversing valve into the defrosting mode, and reversely operate the cooling mode to defrost. One of the biggest disadvantages of the defrosting control method in the prior art is that it is ...

AI Technical Summary

Problems solved by technology

However, the above-mentioned critical temperature is often set too high, because in cold winter, when the temperature of the external unit coil of the air conditioner reaches the critical temperature such as -4°C, although a thin layer of frost forms on the surface of the coil, the entire unit is still It can operate normally and well, especially in northern regions where the outdoor temperature is generally lower than 0°C. This phenomenon is more common. If the defrosting mode is forced to run at this time, it will cause too frequent defrosting and affect the normal indoor heating , reduce the indoor temperature and affect the user experience

However, the critical temperature of defrosting cannot be set too high, otherwise it will be difficult to trigger the defrosting mode, making the frost layer on the outdoor coil thicker and thicker

The same problem exists in the setting of the exit temperature value for exiting defrosting. If it is set too low, the frost layer has not completely melted. If it is set too high, it will prolong the defrosting time, further reduce the room temperature, and make people feel cold.