JPS60233436A - Controller for defrosting of heat pump type air conditioner - Google Patents

Abstract

PURPOSE:To make effective defrosting operations of a heat pump type air conditioner by a method in which when heating operation is switched to defrosting operation, an air blower for outdoor is operated when the temperature of open air is high and open air of a higher temperature than the icing temperature is supplied to the outdoor heat exchanger. CONSTITUTION:A single-pole and double-throw switch 2a is switched to a single pole contact (a) and a double throw contact (c) at the single pole contact (a) and a double throw contact (b) when the temperature of a refrigerant flowing in an outdoor heat exchanger becomes -5 deg.C (most suitable temperature for taking overheating degree). A thermostat 5 for detecting the temperature of open air is closed when the temperature of open air is higher than 2 deg.C but opened when the temperature of open air is lower than 2 deg.C. Even when the temperature of coil is low to -5 deg.C and the switch 2a is switched, the thermostat 5 is closed if the temperature of open air is higher than 2 deg.C, and therefore, the air blower 4 is operated through the thermostat 5 between the contacts a-c of the switch 2a. Air of a temperature higher than 2 deg.C is sent to the air conditioner where the temperature of coil is in a state to be frozen, thereby effectively thawing the ice.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a defrost control device for a heat pump type air conditioner.

Conventional configuration and its problems Conventionally, in a heat pump type air conditioner using a compressor, four-way valve, outdoor heat exchanger, expansion mechanism, indoor heat exchanger, etc. During heating, frost forms and freezes on the outdoor heat exchanger, which acts as an evaporator.

Conventionally, defrosting, which removes this ice, was done by stopping the blower for the outdoor heat exchanger, switching the four-way valve to cooling mode, and flowing high-temperature, high-pressure refrigerant to the outdoor heat exchanger. That is, defrosting is started when the refrigerant temperature is set to -6°C using a thermostat that is attached to the outdoor heat exchanger and senses the refrigerant temperature.

However, with these settings, even though there is no freezing on the coil surface of the outdoor heat exchanger, the defrost operation, that is, the cooling operation, is switched to, resulting in unnecessary defrost operation, which is essentially uneconomical. It had the following drawbacks.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the conventional technology, and aims to provide substantially efficient defrost operation.

Structure of the Invention The present invention comprises a defrost timer motor connected between power supplies, a single-pole double-throw switch switched by the timer motor, an operation switch connected to the single-pole side of the switch, and a double-throw switch connected to the single-pole side of the switch. A blower for an outdoor heat exchanger connected to the normally closed contact side of the throw side, and between the normally open contact side and the blower,
A thermostat contact for detecting outside air temperature and an auxiliary relay connected between the normally open contact side and the power supply and linked to the indoor unit are provided. When the outside temperature is high enough to be used for defrosting, the thermostat contacts are closed and the blower starts operating.

Description of examples An embodiment based on the present invention will be described based on the drawings.

1 is a power source; 2 is a defrost timer motor connected to the power source 1, and connected to a single-pole, double-throw switch 2a. When the temperature of the refrigerant flowing through the outdoor heat exchanger reaches -6°C (an appropriate temperature to take the degree of superheat), this switch 2a switches between the single-pole contact a, the double-throw contact, and the single-pole contact a. and double-throw contact C. 3 is an operation switch with one end connected to a single-pole contact a and the other end connected to power supply 1; 4 is a blower for an outdoor heat exchanger with one end connected to a double-throw contact and the other end connected to power supply 1; 6 is a blower for an outdoor heat exchanger; This is a thermostat for detecting outside air temperature, with one end connected to the double throw contact C and the other end connected between the blower 4 and the double throw contact.When the outside air temperature is higher than 2℃, it is closed, and when it is lower, it is closed. , becomes open. Reference numeral 6 denotes an auxiliary relay, one end of which is connected to a double-throw contact C, the other end of which is connected to the power source 1, and which opens and closes a contact 6a provided between communication terminals 7 to an indoor unit (not shown).

In the above configuration, during heating, the operation switch 3 is turned on to perform the heating operation, but during this operation, if the outside temperature is high and the
°C or higher, and when the timer motor 2 is activated and the coil temperature of the heat exchanger is high, the switch 2a is switched between a and b.
In the meantime, the blower 4 is energized and operated. At the same time, since the outside temperature is 2°C or higher, the thermostat 6 is also closed, and the auxiliary relay 6 is also at contact 2a.

Electricity is applied via the thermostat 5, the contact 6a is closed, and the indoor unit is operated.

Next, when the coil temperature is low and reaches -6°C, switch 2
a switches between contacts a and c. Here, even if the switch 2a is switched, the thermostat 5 is closed if the outside air temperature is 2° C. or higher, so the blower 4 is operated via the mostat 5 between a-a of the switch 2a. When the coil temperature begins to freeze, air at an outside temperature of 2°C or higher is blown to effectively melt the ice.

Next, when the outside temperature falls below 2°C, even if the blower 4 is operated to blow cold air onto the coil, melting will not be accelerated. operation will be stopped. Further, when the switch 2a is between the defrosting contacts a and C, the auxiliary relay 6 is energized, so the contact 6a is opened and the operation of the indoor unit is stopped.

Effects of the Invention As described above, the present invention operates the outdoor blower when switching from heating operation to defrost operation and when the outside air temperature is high, and blows suburban air at a temperature higher than that at which freezing occurs on the outdoor heat exchanger. This is because it blows air to speed up melting.
When ice forms on the outdoor coil at a temperature higher than the freezing temperature, it thaws quickly, allowing for practical and economical defrost operation and shortening the defrost time.

[Brief explanation of drawings]

The drawing is a defrost control circuit diagram according to the present invention. 0 1... Power supply, 2... Timer motor,
2a...Contact, 3...Operation switch,
4...Blower, 5...Thermostat %6...Auxiliary relay.

Claims (1)

[Claims] A defrost timer motor connected between the power supply and
A single-pole double-throw switch that is switched by this timer motor, an operation switch connected to the single-pole contact side of this switch, and an outdoor heat exchanger blower connected to the double-throw normally closed contact side. , a heat pump type in which a thermostat contact for detecting outside temperature is provided between the normally open contact side of the double throw side and the blower, and an auxiliary relay connected between the normally open contact side and the power supply and linked to the indoor unit. Defrost control device for air conditioners.