JPS60169038A - Device to control defrosting in air conditioner of heat pump type - Google Patents

Abstract

PURPOSE:To prevent an erroneous action in a defrosting operation and to heighten the heating efficiency of an air conditioner, by determining the defrosting condition, based on the outputs from a thermo-sensor fitted to the side of an outdoor heat exchanger and from a humidity sensor fitted to the intake side of an outdoor unit. CONSTITUTION:The defrosting condition is determined by a defrosting condition determining circuit 3, based on the outputs from a thermo-sensor 1 fitted to an outdoor heat exchanger and from a humidity sensor 2 fitted to the intake side of an outdoor unit. The result in regard to the defrosting condition is transmitted to a driver circuit 6, taking an output from a defrost-prohibiting and permiting timer 4 into consideration, and the driver circuit 6 drives a four way type valve 7 and a fan 8 to control a defrosting operation.

Description

[Detailed description of the invention] The present invention relates to a defrost control device during vehicle operation.

Conventional configuration and its problems Conventionally, the method for detecting and determining defrost start conditions during heating operation of a heat pump air conditioner is to set a defrost prohibition period for a certain period of time, and then to A defrost allowable time period is established, and within this allowable time,
When the temperature in the outdoor heat exchanger, which functions as an evaporator, falls below a certain predetermined temperature, defrost operation is performed for a permissible period of time. The predetermined temperature is the temperature at which defrost is started, and this temperature automatically slides depending on the outside air temperature, so that as the outside air temperature decreases, the defrost start temperature also decreases.

However, these methods do not detect the humidity of the outside air, which has a large effect on frost formation on the outdoor heat exchanger, so the defrost is effectively applied to the outdoor heat exchanger even though there is no frost formation. This caused a loss of energy and interfered with heating operation as the air conditioning circuit operated.

In addition, an ideal method to solve this problem would be to use a frost detection sensor to detect actual frost formation and perform defrost control, but there are currently problems with this detection method. be. In other words, once frost forms and defrosts, the melted/ζ frost becomes water droplets and deposits on the surface of the frost detection sensor (=J), which impedes subsequent accurate frost detection. Additionally, the frost detection sensor has the disadvantage of being complicated and expensive, such as by providing a heater to evaporate the water droplets.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to accurately detect frost formation, reduce defrost operation, and enhance heating effects.

Structure of the Invention The present invention comprises a temperature sensor attached to an outdoor heat exchanger, a humidity sensor attached to the suction side of the outdoor unit, a circuit that determines defrost conditions based on the information sent from these two sensors, and It has an AND gate that takes a logical product of a defrost condition determination circuit, a defrost prohibition timer, and an allowable timer and outputs the result to a driver circuit, and the driver circuit controls a four-way valve or an outdoor blower to perform defrost. This is what I did.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 is a temperature sensor attached to the outdoor heat exchanger (non-use side heat exchanger) installed in the refrigeration cycle of a heat pump air conditioner, and 2 is installed on the suction side of the outdoor unit to sense the humidity of the outside air. 3 is a defrost condition determination circuit that determines whether the defrost condition is set or not based on the temperature sensor 1 and humidity sensor 2; 4 is a prohibition timer that does not allow defrost, and a timer that performs defrost. 6 is an AND gate that takes the logical product of the outputs of the defrost condition determination circuit 3, the defrost prohibition timer, and the γ1 capacity timer 4, and 6 is an ND gate 6 The driver circuit is driven by the output of the refrigeration circuit and controls the outdoor blower 8 and the four-way valve 7 of the refrigeration circuit, which switches the refrigerant flow path depending on whether it is a defrost operation (cooling) to switch to air conditioning or a defrost stop (heating) operation to switch to heating. .

FIG. 2 is a correlation diagram showing the defrost start zone when the temperature of the outdoor heat exchanger and the humidity of the outside air are determined by the temperature sensor 1 and the humidity sensor 2. The temperature of the exchanger and the humidity of the outside air are sensed by a temperature sensor 1 and a humidity sensor 2, and the signals are sent to a defrost condition determining circuit 3 to determine whether the conditions for defrosting have been met. - 10,000, If defrost is prohibited by the defrost prohibition and allowable timer 4, there will be no output to the AND gate 5, and if defrost is permitted, and the defrost condition judgment circuit 3 determines that the defrost condition has been reached. If so, the AND gate 6 extracts the logical value and outputs it to the driver circuit 6. From this driver circuit 6, the western valve 7. The air is output to the blower 8, the four-way valve 7 is reversed, and the defrost operation (
(cooling operation). To explain the operation start zone of Koshida defrost using the second graph, even if the surface temperature of the outdoor heat exchanger (according to the temperature sensor) is low, if the humidity of the outside air is low, the defrost operation will not be started. The curve A is set, and when the humidity reaches a certain level, the defrost operation starts even when the surface temperature of the outdoor heat exchanger is high j9i (-ts℃).The horizontal line B is set so that the defrost operation starts zone C. This setting is made so that defrost operation starts when defrost is necessary in actual use.

Effects of the Invention As described above, the present invention includes a temperature sensor, a humidity sensor, a defrost condition determination circuit that determines defrost based on the signals transmitted from both sensors, and this defrost condition determination circuit and a defrost prohibition and defrost enable timer. AND which takes the AND and outputs to the driver circuit.
A four-way valve, a blower, etc. are controlled by the driver circuit, and even if the temperature of the outdoor heat exchanger is low, when the humidity is low, heating operation is performed without entering defrost operation, Since the defrost operation is performed in a place where the temperature is high and the humidity is high, the defrost operation is actually performed when necessary, that is, when frost formation is accurately detected. Therefore, the defrost operation is reduced compared to the conventional example, and the heating effect is also increased and energy loss is reduced.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of a defrost control device according to an embodiment of the present invention, and FIG. 2 is a correlation diagram between the temperature of an outdoor heat exchanger and the outside air humidity, showing the setting of the defrost start zone. 1... Temperature sensor, 2... Humidity sensor, 3... Defrost condition determination circuit, 4...
...Defrost prohibition and permission timer, 6...
...AND gate, 6...Driver circuit, 7
...Four-way valve, 8...Blower. Name of agent: Patent attorney Toshio Nakao and one other person
Shokiya Issei

Claims (1)

[Claims] A temperature sensor attached to the outdoor heat exchanger, a humidity sensor attached to the suction side of the outdoor unit, a defrost condition determination circuit that determines defrost based on the signals sent from both sensors, and this defrost condition determination circuit. and an AND gate that performs a logical product with a defrost prohibition timer and a defrost permission timer and outputs the result to a driver circuit, and the driver circuit controls a west valve, a blower, etc. Control device.