JPH0812013B2 - Air conditioner with outside air cooling function - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigeration cycle type air conditioner with an outside air cooling function, and particularly energy saving and compressor protection regarding a backup operation of a compressor when the outside air cooling capacity is insufficient. It is related to the improvement that enables the effect.

[Prior Art] A refrigeration cycle air conditioner with an outside air cooling function that cools the room by using both a cooling function by a refrigeration cycle that uses a refrigerant compressed by a compressor and an outside air cooling function by taking in outside air Then, when the indoor temperature cannot be reduced to the set temperature, that is, when the outside air cooling capacity is insufficient, it is necessary to back up the compressor to compensate for the insufficient cooling capacity.

However, the conventional device, as described in Catalog 50EG-1P, Pages 13, 14 issued by U.S. carrier company 1980, when the outside air temperature is below the predetermined outside air cooling switching temperature, the compressor remains stopped and the outside air Backup operation is not performed when the cooling capacity is insufficient.

On the other hand, in the examples described in Hitachi Technical Catalog SP1-801 P14, P24 and Japanese Patent Application No. 62-275756, the compressor is backed up when the outside air cooling is insufficient, but the outside air temperature is 17 ° C or more. When the outside temperature is lower than the temperature, it prevents frost formation on the evaporator, and eventually prevents the compressor accident caused by returning to the compressor as a partial liquid without completely evaporating the refrigerant. Therefore, the compressor remains stopped.

[Problems to be Solved by the Invention] As described above, the prior art is not able to secure the possibility of backup operation of the compressor when the outside air cooling capacity is insufficient and to expand the lower limit of the operation range. There was no consideration, and there was a problem that there was no means for compensating for the lack of outside air cooling capacity for a room with a low set room temperature or for a room with a large change in internal load.

An object of the present invention is to widen the lower limit outside air temperature of the compressor backup operation range performed when the outside air cooling capacity is insufficient without causing frosting of the evaporator and thus accidents of the compressor, and in a highly energy-saving manner. It is in.

[Means for Solving the Problems] The above object is achieved by an air conditioner with an outside air cooling function described in each of the claims.

[Operation] When the indoor temperature cannot be lowered to the set temperature by the introduction of the outside air, that is, when the outside air cooling capacity is insufficient, the backup operation of the refrigerant compressor is performed. During this backup operation, even if the temperature of the introduced outside air is low, the mixing ratio of the mixed air is controlled so as to maintain the temperature of the mixed air at a temperature at which the evaporator is not frosted, and the refrigeration cycle operates normally.

Is this control based on the detection of the temperature of the mixed air,
Alternatively, it is performed by controlling the mixing ratio of the mixed air in a predetermined relationship based on the detection of the outside air temperature and the indoor air temperature.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, FIG.
And FIG. 4 demonstrates.

FIG. 1 is an example of the entire system when the present invention is applied to an air-cooled split type air conditioner with an outside air cooling function. An outdoor unit 5 including a refrigerant compressor (MC) 1, a condenser 2, an outdoor blower 3, an outdoor blower motor (MCF) 3a, and a refrigerant decompression mechanism 4 is installed outdoors. On the other hand, the indoor unit 15 includes a refrigerant evaporator 6, an indoor blower 7, and an indoor blower motor (MEF) 7a. Outside air duct 22 and return air duct 2
There is a damper drive device (DMA) 8 and a damper mechanism 9 provided at the intersection with 1, and there is a control device 10 tangential to the power supply. The indoor unit 15 is connected to a discharge duct 20 into the room, a return air duct 21 from the room, and an outdoor air duct 22 that takes in outdoor air. The indoor unit 15 and the outdoor unit 5 are connected by a pipe 51 to form a refrigeration cycle.

Outside air temperature sensor (ThO) 1 installed in outside air duct 22
1, an indoor temperature sensor (ThR) 12 installed in the room 52, a mixed air (mixed air of indoor return air and outside air) temperature sensor (ThM) 1 installed between the damper mechanism 9 and the suction side of the evaporator 6
3 and remote control device (RMC) 14 installed in room 52
Are connected to the control device 10 by signal lines, respectively.

The control device 10 has a comparison means for periodically comparing the room temperature and the room temperature set value, and a control means for controlling the operation of the compressor 1 and the damper drive device (DMA) 8 based on the output of the comparison means. It is provided.

When the damper drive device (DMA) 8 rotates normally, the damper mechanism 8
Rotates in the direction of arrow A to take in more outside air and at the same time reduces the amount of return air from the inside of the room. When it is reversed, the damper mechanism 9 rotates in the direction of arrow B to reduce the amount of outside air taken in and return from the room. It is configured to be large in volume.

Further, as shown in FIG. 2, the damper drive device (DMA) 8
At the position where the damper mechanism 9 is fully opened on the introduction side of the outside air 60,
That is, the fully open position limit switch (LSP) 17a that is turned off at the position 53 where the amount of the indoor return air 61 becomes zero, and conversely, the position where the damper mechanism 9 is fully closed on the outside air introduction side, that is, the indoor return air amount is A fully closed position limit switch (LSN) 17b that is turned off at a position 54 where the maximum amount of outside air intake is zero is provided and connected to the control device 10. Further, a potentiometer (PTM) 18 whose resistance value changes in association with the rotation of the damper motor (MD) 16 is connected to the damper motor (MD) 16.
Further, the damper motor (MD) 16 is a reversible rotation type motor, and rotates forward (rotates in the direction of arrow A) when a voltage is applied between the terminals P and C, and rotates reverse (when the voltage is applied between N and C). It rotates in the B direction) and stops if no voltage is applied between the pair of terminals. The voltage detection terminal of the potentiometer (PTM) 18 is connected between R _{1 and} R _2, and is processed by the microcomputer to give the minimum opening of the damper when this voltage detection value is equal to the damper minimum opening setting value.

The operating circuit is shown in FIG. The control device 10 includes an operation switch 14a, a weak wind switch (SFL) 14b, a strong wind switch (SFH) 14c, a cooling switch (SC) 14d, and a room temperature setting device (ATRMS) 14e in the remote control device (RMC) 14 as inputs. Each setting state, outside air temperature sensor (ThO) 11, indoor temperature sensor (ThR) 12, mixed air temperature sensor (ThM) 13
And the detected values of potentiometer (PTM) 18 are respectively taken in, and the set values of damper minimum opening setting device (AMO) 19a, mixed air temperature setting device (ATMS) 19b and outside air cooling switching outside air temperature setting device (ATOS) 19c are set. After comparing and calculating
It is connected so that the result can be output. Each of these control outputs is used for the indoor blower motor strong wind operation relay (ARH) 10a or the indoor blower motor weak wind operation relay (AR
L) 10b to the multi-speed indoor blower motor 7a, and the compressor relay (ARC) 10 to the compressor (M
C) 1a and outdoor blower motor (MCF) 3a, damper forward rotation relay (ARP) 10d or damper reverse rotation relay (AR)
N) is supplied to the damper motor (MD) 16 via 10e.

Note that FIG. 4 is a block control diagram for controlling this air conditioner by a microcomputer, and an input circuit 60 for inputting room temperature t _RM , outside air temperature t _O and mixed air temperature t _M ;
Room temperature set value t _RMS , mixed air temperature set value t _MS , outside air cooling switching outside air temperature set value t _OS, and memory circuit 70 for storing damper minimum opening set value; room temperature t _RM and room temperature set value t
_RMS , the outside air temperature t _O and the outside air cooling switching outside air temperature set value t _OS , the outside air temperature t _O and the compressor backup operation minimum outside air temperature t _BMIN when the damper is fully opened, and the mixed air temperature t
_M and the mixed air temperature set value _tMS are compared and calculated to control the opening of the damper mechanism 9, the operation of the compressor 1 and the indoor and outdoor blowers 3 and 7, and the backup operation control of the compressor described below. An arithmetic processing unit 80 and a control unit 90 for performing the processing are provided.

Next, taking the operation circuit of FIG. 3 as an example,
According to the explanation No. of Table 1, the operation will be described with reference to FIGS. 5 and 6. In Table 1 Means the backup operation of the compressor, and the meaning of t _MRO is shown below Table 1.

Description No. 1; When the start / stop switch (SO / F) 14a of the remote control device (RMC) 14 is turned off at power-on or during operation, the control device 10 is the damper reverse rotation relay (ARN) 10e. Is turned on, the damper motor (MD) 16 is reversely rotated until the fully closed position limit switch (LSN) 17b is turned off, and the damper mechanism 9 is fully closed to the outside air duct 22 and does not introduce outside air. All other motors are turned off, so operation will not start.

Explanation No.2; After that, the remote control device (RMC) 14 strong wind switch (SF
H) 14c is turned on, the control device 10 turns on the damper forward rotation relay (ARP) 10d, and the potentiometer (PTM) 18 whose resistance value changes in association with the rotation of the damper motor (MD) 16
When the rotation angle information calculated based on the voltage detected in step 3 becomes equal to the damper minimum opening setting value set in the damper minimum opening setting device (AMO) 19a, the damper forward rotation relay (ARP) 10d
Turn off and stop the motion with the damper open. Therefore, through the opening of the damper mechanism 9, the indoor blower introduces a necessary amount of outside air into the room during normal operation. The damper mechanism 9 is also controlled when the weak wind switch (SFL) 14b is turned on.

Description No.3; Outside air temperature t _O is outside air cooling switching outside air temperature setting device (ATOS)
When the outside air cooling switching outside air temperature t _OS set in 19c is higher, 14 cooling switches (S
C) When 14d is turned on, or when t _O ≥t _OS during cooling operation, the room temperature t _RM is the room temperature setting device (ATRMS) 14c
When the room temperature setting value t _RMS set by is higher than the damper forward rotation relay (ARP) 10d and damper reverse rotation relay (ARN) 10e, the compressor relay (ARC) 10c remains off.
Is turned on, the compressor motor (MC) 1a and the indoor blower motor (MCF) 3a are operated, and the system enters the cooling operation state by the refrigeration cycle operation. Damper mechanism 9
Since it is at the minimum opening degree, excessive high temperature outside air is not introduced into the room, and the room temperature does not suddenly rise.

Explanation No.4; Under the same conditions as the explanation No.3, if the room temperature t _RM fluctuates within the differential of the room temperature set value t _RMS , the damper relays (ARP) 10d, (ARN) 10e are OFF. As it is, the compressor relay (ARC) 10c is turned on and off, so the compressor motor (MC) 1a and the indoor blower motor (MCF) 3a
Starts / stops, and the system turns on / off the cooling operation / stop by the refrigeration cycle operation. The damper mechanism 9 has the minimum opening degree, and is the same as the above description No. 3.

Explanation No. 5; Under the same conditions as the explanation No. 3, if the relationship between the room temperature t _RM and the room temperature set value t _RMS is t _RM <t _RMS , the damper relay (ARP) 10d, (ARN ) 10e, compressor relay (ARC) 1
Since 0c remains OFF, the operating state becomes the same as the above-mentioned explanation No. 2, and the damper mechanism 9 has the minimum opening degree.
Same as No.3.

Explanation No.6; The relationship between the outside air temperature t _O and the outside air cooling switching outside air temperature t _OS is t _O.
<When t _OS , if the cooling switch (SC) 14d is turned on,
When the room temperature t _RM is lower than the room temperature set value t _RMS and lower than t _RMS -differential α, the compressor relay (AR
C) 10c is turned off, so cooling operation by refrigeration cycle is not performed, and damper relays (ARP) 10d, (ARN) 10e are also OF
Since it is still F, the damper mechanism 9 has the minimum opening,
The indoor blower introduces the required amount of outside air into the room.

Explanation No. 7; If the room temperature t _RM fluctuates within the differential of the room temperature set value t _{RMS under} the same conditions as the explanation No. 6, the compressor relay (ARC) 10c is off. The cooling operation by the refrigeration cycle is not performed, and when the outside air temperature t _O fluctuates, the damper forward rotation relay (ARP) 10d and the damper reverse rotation relay (ARN) 10e are turned on and off, and the damper mechanism 9 is rotated in the forward and reverse directions. Therefore, the mixed air temperature t _M is the mixed air temperature set value.
Adjusted to be equal to t _MS , the system is in the ambient air introduction operating state.

Description No.8; outside air temperature t _O is the compressor backup driving minimum outside air temperature t
_If the room temperature t _RM is higher than the room temperature set value t _RMS by the differential α or more in a range higher than BMIN and lower than the outside air cooling switching outside air temperature t _OS , the damper forward rotation relay (ARP) 10d is turned on, The damper mechanism 9 is fully opened, the compressor motor (MC) 1a is operated, and the unit is in a compressor backup operation mode for introducing all outside air when the outside air cooling capacity is insufficient.

Explanation No. 9; Room temperature is the same as the explanation No. 8 In the backup operation state of the compressor 1, the outside air temperature t _O is the backup operation minimum outside air temperature t
If it becomes lower than _BMIN , the damper reverse rotation relay (AR
N) 10e is turned on, and the damper mechanism 9 changes the mixed air temperature t _M to t.
_{At the} point _where it becomes equal to _BMIN , the relay (ARN) 10e is turned off, so stop. As a result, the inlet temperature of the evaporator 6 does not _fall below the backup operation minimum outside air temperature t _BMIN, so there is no fear of frost formation on the evaporator, and the damper mechanism 9 is kept at a temperature lower than that in the cooling operation at the minimum opening position. Therefore, there is an energy saving effect.

FIG. 6 shows changes in the damper opening and the evaporator inlet air temperature according to the present invention with respect to changes in the outside air temperature on the section ZZ ′ in FIG. 5, and the conventional compressor backup operation is backup operation. Although it was stopped at the minimum outside air temperature t _BMIN , the present invention introduces the above-mentioned low temperature outside air while preventing frosting of the evaporator even when the temperature of the outside air is lower, thereby saving energy. It is understood that the compressor backup operation can be performed while playing.

Next, another embodiment will be described with reference to FIG. This example is a method that is carried out without detecting the temperature t _M of the mixed air of the indoor return air and the outside air, and the focus is on the fact that the outside air introduction ratio is almost determined by the damper opening.

That is, assuming that the amount of outside air introduced is V _O and the amount of indoor return air is V _R , the mixed air temperature t _M is Therefore, the outside temperature t _should be set so that the above-mentioned t _M becomes _larger than the minimum outside-air temperature t _{BMIN for the} compressor backup operation.
The opening of the damper is set for _O. In this case, with respect to the minimum indoor return temperature t _R (for example, 20 ° C)
When t _BMIN is set, the mixed air temperature t _M becomes slightly _higher than t _{BMIN with} respect to the maximum temperature of t _R (for example, 27 ° C.), but the basic effect does not change.

Conversely, t _O and t _R may be detected, and the damper may be driven by setting the ratio of the outside air introduction amount V _O from the calculation formula of t _{M based on} the relationship.

In the above embodiment, the means for detecting the mixed air temperature t _M is provided on the outlet side of the evaporator and also serves as another blown air temperature detecting means, and the same effect as the first embodiment can be obtained.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it is possible to widen the lower limit of the compressor backup operation at the time of insufficient outdoor air cooling without causing frost formation on the evaporator, and thus to temporarily increase indoor cooling. It has the effect of always exhibiting sufficient cooling capacity against load.

Further, compared with the conventional method of cooling the compressor with the minimum amount of outside air, the air temperature at the inlet of the evaporator is kept at a low temperature, so there is an energy saving effect.

[Brief description of drawings]

FIG. 1 is an overall system configuration diagram showing an embodiment of the present invention,
FIG. 2 is a detailed view showing an example of the damper drive device, FIG. 3 is an operation block diagram of the same embodiment, FIG. 4 is a microcomputer control block diagram of the same embodiment, and FIG. 5 is an outside air temperature and an indoor temperature in the same embodiment. FIG. 6 is a diagram showing the relationship between the damper opening and the evaporator inlet temperature on the section ZZ ′ in FIG. 5, and FIG. 7 is an operation of another embodiment. FIG. 1 ... compressor, 1a ... compressor motor (MC) 2 ... condenser, 3 ... outdoor blower 3a ... outdoor blower motor (MCF) 4 ... decompression mechanism, 5 ... outdoor unit 6 ... evaporator, 7 ... indoor blower 7a ... Multi-speed indoor blower motor (MEF) 8 ... Damper drive device (DMA) 9 ... Damper mechanism, 10 ... Control device 11 ... Outside air temperature sensor (ThO) 12 ... Indoor temperature sensor (ThR) 13 ... Mixed air temperature sensor (ThM ) 14 ... Remote control device (RMC) 15 ... Indoor unit 16 ... Damper motor (MD) 17a ... Full open position limit switch (LSP) 17b ... Full closed position limit switch (LSN) 18 ... Potentiometer (PTM) 14a ... Run / stop switch (SO / F) 14b ... Low wind switch (SFL) 14c ... High wind switch (SFH) 4d ... Cooling switch (SC) 14e ... Room temperature setting device (ATRMS) 19a ... Damper minimum opening setting device (AMO) 19b ... Mixed air Temperature setting device (ATMS) 19c ... Outside air cooling switching temperature setting Equipment (ATOS) 10a… Indoor blower motor strong wind operation relay (ARH) 10b… Indoor blower motor weak wind operation relay (ARL) 10c… Compressor relay (ARC) 10d… Damper forward rotation relay (ARP) 10e… Damper Reverse rotation relay (ARN) 20… Discharge duct, 21… Return air duct 22… Outside air duct

Claims (4)

[Claims] A refrigeration cycle is constructed by connecting an outdoor unit consisting of a refrigerant compressor, a condenser, an expansion valve and an outdoor blower to an indoor unit consisting of a refrigerant evaporator and an indoor blower to form a refrigeration cycle. Has an air passage for supplying the air that has passed through the evaporator to the room to be air-conditioned, and for supplying the recirculated air from the outside air and the room to the air inlet side of the evaporator. In an air conditioner with an outside air cooling function equipped with a damper mechanism for adjusting in the air passage, when the temperature of the introduced outside air is equal to or lower than the temperature at which frost is formed on the evaporator, the introduced outside air supplied to the air inlet side of the evaporator is It is characterized by including a control device for performing a backup operation of the compressor by controlling the damper mechanism so that the temperature of the mixed air with the return air from the room is equal to or higher than the frosting temperature. Outdoor air cooling function with air conditioning system to be. 2. The air conditioner with an outside air cooling function according to claim 1, wherein the control of the air amount adjusting mechanism is performed according to a detected temperature of the outside air. 3. The air conditioner with an outside air cooling function according to claim 1, wherein the control of the air amount adjusting mechanism is performed based on the detected temperature of the mixed air. 4. The air conditioner with an outside air cooling function according to claim 1, wherein the control of the air amount adjusting mechanism is performed based on each detected temperature of outside air and room air.