Defrosting detector and defrosting control method based on frost layer thickness

Abstract

The invention discloses a defrosting detector and a defrosting control method based on the frost layer thickness, belonging to the field of air source heat pump control, and aiming at solving the problems of the inaccurate judgement of defrosting by adopting an indirect method for the existing air source heat pump and over high cost. According to the invention, an insulative layer is coated at the outer surface of a heating resistor, and first electrode pairs A-A' are arranged at the left and right of the heating resistor. The defrosting control method is as follows: in non-working state of the defrosting detector: disconnecting all switches; in the starting up state of the defrosting detector: starting the defrosting detector at the temperature of minus 12 DEG C- 1 DEG C the switching off, intermittently the switching on and off; in the starting state of defrosting: heating the resistor to work, conducting the first electrolde pairs A-A' by a frost melting water film, and outputting defrosting signals; in the defrosting state of the air source heat pump: conducting a second electrode pair B-B' by the frost melting at the surface of the fin; and in the defrosting suspending state of the defrosting detector: determining that the defrosting is finished when the output voltage signal is zero.

Description

technical field [0001] The invention relates to a defrosting detector based on frost layer thickness and a defrosting control method, belonging to the field of air source heat pump control. Background technique [0002] The existing defrosting control strategies for air source heat pumps are divided into two types: indirect method and direct method. Most of the existing defrosting methods are indirect methods, mainly including the following: [0003] 1. Timing control method, time temperature method. This type of method sets the defrosting time to a fixed value, which cannot take into account the changes in ambient temperature and humidity, and cannot accurately grasp the defrosting entry point, which is prone to misoperation, and this method is more sensitive to the installation position of the temperature sensor. The common installation in the middle may easily lead to inaccurate judgment of the end of frosting and unclean defrosting. [0004] 2. Self-correcting defrost...

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Problems solved by technology

[0013] The purpose of the present invention is to solve the inaccurate defrosting judgment existing in the indirect method of defrosting the air source heat pump; the theory is beautiful but the practical application is difficult; the cost is too high, so it is difficult to popularize; some sensitive components are vulnerable to outdoor environment A series of problems such as low reliability of long-term use; the direct method has the problems of high cost, large volume, and inconvenient installation. A defrosting detector and defrosting control method based on the thickness of the frost layer are provided.

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