AU636062B1

AU636062B1 - Frost removing control circuit for an air conditioner using a heat pump

Info

Publication number: AU636062B1
Application number: AU85503/91A
Authority: AU
Inventors: Gi-Weon Han
Original assignee: Gold Star Co Ltd
Current assignee: LG Electronics Inc
Priority date: 1991-10-01
Filing date: 1991-10-01
Publication date: 1993-04-08
Anticipated expiration: 2011-10-01
Also published as: DE4133112A1; DE4133112C2

Description

P/0000l1 Regul:o 3.2

AUSTRALIA

Patents Act 11990 COIMPLETJE SPECIWIC51ON FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: GOLDSTAR CO., LTD.

Actual Inventor(s): Gi-Weon HAN Address for service in Australia: 0 CARTER SMITH BEADLE Qantas House 2 Railway Parade Canmberwell Victoria 3124 Australia Attorney Code SA Invention Title: FROST REMOVING CONTROL CIRCUIT FOR AN AIR CONDITIONER USING A HEAT PUMP

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The following statement is a full description of this invention, including the best method of performing it known to us: Our Ref.: #8921 JRG:WB 09-llgoi -1I- FIELD OF THE INVENTION The present invention concerns a frost removing control circuit for an air conditioner using a heat pump, and more particularly a circuit for controlling the driving of a fan S- for producing a current of air toward the inside of a room.

BACKGROUND OF THE INVENTION A conventional frost removing control circuit for an air conditioner using a heat pump comprises, as shown in Fig. 1, a frost removing control timer TM connected between both [0 terminals of a alternating current power supply (AC 220V), a reverse valve RV connected in series with switches SW1 and oSW2, a motor M for driving a fan for producing a current of :..00 air toward the inside of a room, and switches SW3 and SW4 for switching the motor M. The timer TM is connected in parallel \5 with the reverse valve RV.

e In this conventional frost removing control circuit, when the air conditioner serves as the heat pump, the switch SW2 connected in series with the reverse valve RV is on and the switch SW1 of the frost removing control timer TM is connected to the reverse valve RV, so that the refrigerant reversely flows so as to cause the heated air current to flow toward the inside of a room. Namely, the refrigerant of a high temperature and high pressure flows to the condencer disposed in the inside of the room supplying heat thereto by the air current produced by the fan disposed in the inside of the room. Then the refrigerant flows to the evaporator disposed in the outside of the room changed to the state of low pressure and low temperatuie, thus discharging cold air outside by the rotation of the fan disposed in the outside of the room. This procedure is repeated obtaining a desired temperature of the room.

H* However, if the tcdoor temperature is too low in i* i 0 0

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S SS* IinIter, uthe i rrigerant r i in uu iut u the rouuin ma iiciLai n low pressure and low temperature discharging the cold air, so )o that the outside temperature is too lowered so as to cause the evaporator to be frozen. Consequently, the refrigerant of the evaporator cannot properly function, thus severely "degrading the heat pumping efficiency of the air conditioner.

In this case, the switch SW1 of the frost removing control timer TM is separated from the reverse valve RV after a predetermined time, so that the refrigerant in the outside of the room gets high pressure and high temperature, thus melting the frost formed in the evaporator. When the operation of the frost removing control timer TM is ended, the switch SWI of the frost removing control timer TM is connected to the reverse valve, so that the air conditioner functions as the heat pump.

\0 Such a conventional frost removing control circuit has the disadvantage that when the refrigerant in the outside of.

the room gets high pressure and high temperature in the frost removing mode so as to cause cold refrigerant to flow in the condenser, a cold air current is discharged into the room by I" the rotation of the fan (hereinafter referred to as internal fan) disposed in the inside of the room, thus degrading the heating efficiency, •SUMMARY OF THE INVENTION It is the principal object of the present invention to O provide means for stopping the rotation of the internal fan in the frost removing mode of the air conditioner as a heat -4pump in order to prevent the cold air current flowing into the room from the condenser, thereby improving the heating efficiency.

According to the present invention, there is provided a frost removing control circuit for an air conditioner using a heat pump comprising a frost removing control timer including a switch, the switch being turned on for a predetermined frost-removing time when the outdoor temperature is below a predetermined temperature; a switching means for generating a frost removing signal when said switch of said frost removing timer is on; a rectifying means for transforming an AC current into DC current and providing said DC current to said switching means; i a plurality of relay means connected to a reverse valve and to a fan o motor respectively; and oooo a frost removing control means for activating or deactivating said relay S: 15 means to activate or deactivate said reverse valve and said motor, said

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control means being arranged to deactivate said relay means to deactivate said reverse valve and said fan motor when said frost removing signal is applied to said control means.

The present invention will now be described with reference to the drawings attached only by way of example.

BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS Fig 1 is a schematic diagram for illustrating a JRG:DMW\spe#8921.cL 18 January 1993 conventional frost removing control circuit of an air conditioner as a heat pump; Fig. 2 is a schematic diagram for illustrating the inventive frost removing control circuit of an air conditioner as a heat pump; and Fig. 3 is a flow chart for describing the operation of a microcomputer used in the inventive circuit.

DETAILED DESCRIPTION OF A CERTAIN PREFERRED EMBODIMENT Referring to Fig. 2, a reverse valve RV and the contact jo switch la of a relay coil RY1 are connected in series between both terminals of alternating current supply (AC 220V). A frost removing control timer TM'is connected in parallel with the reverse valve RV. The motor for driving the internal fan for producing a current of air toward the inside of the room is connected through the contact switches 2a and 3a connected in series of relay coils RY2 and RY3 to the AC supply.

9* Through a resistor R1, diode D1 and capacitor C1 are connected the light emitting element of a photocoupler IC1, resistor R2 and the switch SW1 of the frost removing control timer TM to the AC supply. The light receiving element of the photocoupler IC1 and the input Io of a microcomputer 1 are connected through a resistor R3 to a direct current supply Vcc. The outputs 00 0, and 02 of the microcomputer 1 S are respectively through buffers B1, B2 and 83 to the relay coils RY1, PY2 and RY3.

In operation, when a signal of high level from the output O o of the microcomputer 1 is applied to the relay coil RY1, and thus the contact switch la is on, the reverse )0 valve RV is'.-connected to the AC supply (220V) driven to perform the heat pumping.

*oo While the air conditioner is serving as the heat pump,

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and the outdoor temperature is kept below a certain value, 69 Sthe evaporator is frozen, which causes the closing of switch of the frost removing control timer TM, so that the AC current (220V) is rectified through the resistor R1, diode 01 and condenser C1 applied to the photocoupler IC1. Thus the internal transistor of the photocoupler IC1 is on so as to provide a sgnal of low level t the input prt of the provide a signal of low level to the input port Io of the microcomputer 1.

Then, as shown in Fig. 3, the microcomputer 1 outputs the signal of low level through the output ports 00,01,02 so that the current does not flow through the buffers 81, 82, B3 to the relay coils RY RY2, RY3 so as to open the corresponding contact switches la, 2a, 3a. Thus the motor M for driving the internal fan is stopped together with the reverse valve. Then the air conditioner changes the functional state to refrigerating mode, thereby melting the \0 frost formed in the condenser.

After a. predetermined time, if the frost removing control timer TM is stopped and the switch SW1 is opened to stop the photocoupler IC1, the microcomputer 1 receives the signal of high level through the input port I 0 to output

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so that the current flows through the buffers B1, B2, B3 to the relay coils RY1 RY2, RY3 closing the corresponding contact switches la, 2a, 3a. Consequently the motor M drives the internal fan, and simultaneously the reverse valve RV is also driven, so that the air conditioner performs the normal heating function.

As stated above, when the air conditioner using a heat pump is in the frost removing mode, the inventive circuit controls the internal fan to be stopped so as to prevent the cold ai current from the condenser from flowing into the room, thus improving the heating efficiency.

Although the invention has been described in conjunction with specific embodiments, it is evident that many alternatives \0 and variations will be apparent to those skilled in the art in light of the foregoing description, accordingly, the invention is intended to embrace all of the alternatives and variations that fall within the spirit and scope of the appended claims.

The claims form part of the disclosure of this specification.

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Claims

1. A frost removing control circuit for an air conditioner using a heat pump comprising: a frost removing control timer including a switch, the switch being turned on for a predetermined frost-removing time when the outdoor temperature is below a predetermined temperature; a switching means for generat;ng a frost removing signal when said switch of said frost removing timer is on; a rectifying means for transforming an AC current into DC current and providing said DC current to said switching means; a plurality of relay means connected to a reverse valve and to a fan motor respectively; and a frost removing control means for activating or deactivating said relay i. means to activate or deactivate said reverse valve and said motor, said control means being arranged to deactivate said relay means to deactivate said reverse valve and said fan motor when said frost removing signal is applied to said control means.

2. A frost removing control circuit as claimed in claim wherein said switching means comprises a photocoupler. 20

3. A frost removing control circuit for an air conditioner using a heat ,mp substantially as described with reference to Figures 2 and 3 of the accompanying drawings. DATED: 18 January 1993 CARTER SMITH BEADLE Patent Attorneys for the Applicant: A GOLDSTAR CO, LTD 18 January 1993 ABSTRACT Disclosed is a frost removing control circuit (Figure 2) for an air conditioner using a heat pump at controls the internal fan for producing a current of air toward the inside of a room. The circuit is able to stop the fan so as to prevent the cold air current from the condenser from flowing into the room, thus improving the heating efficiency, when the air conditioner is in the frost removina mode. If the frost removing function is completed, the internal fan is driven again by motor M.

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