JPS5854332B2 - Defrosting control method for air conditioners - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a defrosting control method for, for example, a heat pump type air conditioner, in which a defrosting operation time is set according to the amount of frost to perform appropriate defrosting control. The purpose is to

Conventionally, defrosting control methods for heat pump air conditioners have been configured to perform defrosting operation for a certain period of time after detecting a frosting state, or to perform defrosting operation when the outdoor heat exchanger temperature reaches a predetermined value. In either case, there is a problem in that the temperature sensor does not recover due to residual frost or the influence of wind, resulting in an empty defrosting operation.

This invention takes into account the above-mentioned conventional problems, sets the defrosting operation time according to the temperature of the outdoor heat exchanger during frosting, and controls the defrosting operation accurately and efficiently. Next, this invention will be explained in detail with reference to the drawings showing one embodiment thereof.

In the figure, 1 and 2 are first and second temperature sensors consisting of sensors that detect the outside air temperature and outdoor heat exchanger temperature, respectively, and 3 is the first and second temperature sensors. This is a temperature detection circuit that converts the values detected in Steps 1 and 2 into temperature values using a double integration method or the like, and is, for example, an AD converter.

4 is a temperature data signal A of the outside air temperature and the outdoor heat exchanger temperature output from the first output terminal a of the temperature detection circuit 3;
detects the frosting state and sends the frosting detection signal B at regular intervals.
This is a frost detection circuit that outputs, for example, the outside temperature
, if the outdoor heat exchanger temperature is Y, then Y<aX-To
(a: 7/1 (,, To: 10)) It is determined whether or not the frosting condition is met, and if the condition is met, a pulse is output as the frosting detection signal B every 10 seconds. .

5 counts 1 each time a pulse of the frost detection signal B output from the frost detection circuit 4 is input, and when a predetermined count is counted up, a defrost start command signal channel and a temperature data output command signal are sent. For example, when the number of input pulses cumulatively reaches 18 counts corresponding to 3 minutes, it outputs the defrost start command signal C, and when the count increases to 1, it performs the same operation. repeat.

Reference numeral 6 denotes a defrost control circuit which operates when a defrost start command signal C is input to an input terminal C and performs defrosting operation, and when the defrost start command signal C is input, the four-way valve 7 is set to the cooling side. At the same time, a signal is output that causes the heater 8 and the blower 9 to perform predetermined operations, and defrosting operation is started.

Reference numeral 10 stores the temperature data signal E of only the outdoor heat exchanger temperature outputted from the second output terminal S of the temperature detection circuit 3, and also stores the memory signal F when the temperature data output command signal from the counter circuit 5 is input. The memory is refreshed every time the temperature data signal E is input from the second output terminal of the temperature detection circuit 3, and the newest temperature data signal E is always stored.

11 is a defrosting time calculation circuit that calculates the defrosting operation time based on the memory signal F from the temperature data storage circuit 10 and outputs the time setting signal G; 12 is a defrosting operation timer that is set by the time setting signal G; can be.

When the time has elapsed, a defrosting end command signal H is output and applied to the control terminal d of the defrosting control circuit 60.

Next, the operation of the embodiment will be explained.

The temperature detection circuit 3 outputs temperature data signals A and E, and when the temperature data signal A output from the first output terminal a of the temperature detection circuit 3 satisfies the frost formation condition, the frost formation detection circuit 4
A frost detection signal B is outputted at regular intervals, and a counter circuit 5 counts this frost detection signal B. When a predetermined number of counts is reached, a defrosting start command signal C is outputted.

Then, the defrosting control circuit 6 is activated by the defrosting start command signal C and shifts to a defrosting sequence, the four-way 9f7-%- and the outdoor fan 9 are turned off, and the heater 8 is turned on.
Defrosting operation starts.

On the other hand, from the second output terminal Skara of the temperature detection circuit 3, a temperature data signal E of only the temperature of the outdoor heat exchanger is outputted at regular intervals, and this temperature data signal E is sent to the temperature data storage circuit 10.
The memory is refreshed each time input is input to the temperature data storage circuit 10, and the memory signal F stored in the temperature data storage circuit 10 is output from the temperature data output command signal DK from the counter circuit 5. is refreshed and always stores new temperature data, so the memory signal F output from the temperature data storage circuit 10 is the temperature data of the outdoor heat exchanger temperature immediately before the start of the defrosting operation, and the next When the defrosting operation time is calculated by the defrosting time calculation circuit 11, it is calculated based on the outdoor heat exchanger temperature immediately before the start of the defrosting operation.

This means that the amount of frost formed is proportional to the outdoor heat exchanger temperature, so the amount of frost formed just before the start of defrosting operation was detected and the defrosting operation time was calculated according to the amount of frost formed. Defrosting operation is carried out effectively without leaving frost residue.

When the defrosting operation timer 12 times up, a defrosting end signal H is output, and the defrosting control circuit 6 returns to normal operation.

In the above embodiment, the frosting state is detected based on the outside air temperature and the outdoor heat exchanger temperature, but the frosting state may be detected only based on the outdoor heat exchanger temperature.
In that case, the configuration is further simplified.

As described above, according to the defrosting control method for an air conditioner of the present invention, the temperature of the outdoor heat exchanger that satisfies the frost formation conditions and the temperature of the outside air or the predetermined temperature of the outdoor heat exchanger are reached and frost is formed. The state is detected and the defrosting operation is started, and the defrosting operation time is calculated based on the temperature of the outdoor heat exchanger immediately before the start of the defrosting operation, and the defrosting operation time is set in the defrosting operation timer, and the defrosting operation time is set. By performing the defrosting operation, the conventional frost remaining button, empty defrosting operation, etc. are eliminated, and the defrosting operation can be performed effectively.

[Brief explanation of drawings]

The drawing is a block diagram of one embodiment of the defrosting control method for an air conditioner according to the present invention. 10... Memory circuit, 12... Timer for defrosting operation.

Claims (1)

[Claims] 1. Defrost operation is started by detecting the frosting condition based on either the outdoor heat exchanger temperature and outside air temperature that satisfy the frosting conditions or the predetermined outdoor heat exchanger temperature, and the defrosting operation is started immediately before the start of the defrosting operation. A defrosting control method for an air conditioner, characterized in that the defrosting operation time is calculated based on the outdoor heat exchanger temperature, the defrosting operation time is set in a defrosting operation timer, and the defrosting operation is performed for the set defrosting operation time. .