JPH05272820A - Air conditioner - Google Patents

Abstract

PURPOSE:To perform a direct following-up against an operating condition of an air conditioner or a rapid variation in environment of use of the air conditioner and adjust a degree of opening of an expansion valve by a method wherein an objective degree of opening of the expansion valve is determined based on a return air temperature, an outer air temperature and an output of a compressor. CONSTITUTION:A return air temperature sensor 13 acting as a return air temperature selecting means and a compressor controller 14 for use in controlling an output P of a compressor 2 are connected to a controller H, an invertor frequency (f) is adjusted in such a manner that a return air temperature (tr) may approach an objective return air temperature (trm) based on detected information of the return air temperature sensor 13 and there is provided a compressor output adjusting means 101 for use in adjusting the temperature adjusting capability of a heat exchanger 1A acting as an evaporator. In addition, an outer air temperature sensor 15 acting as an outer air temperature sensing means and an expansion valve controller 4a for use in operating to open or close the electrical expansion valve 4 are connected to the controller H, thereby an objective degree of opening Sm of the thermal expansion valve 4 is calculated based on the return air temperature (tr), the outer air temperature (to) and the compressor frequency (f) and there is provided a valve controlling means 102 for adjusting the degree of opening of the expansion valve S to the objective degree of opening Sm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an evaporator, one of which is
A heat pump provided with the indoor air heat exchanger and the outdoor air heat exchanger, the other of which functions as a condenser, the compressor, and the electric expansion valve is provided, and the indoor air heat exchanger heats up the heat. An air supply path for supplying conditioned temperature-controlled air to the air conditioning target room and a return air path for connecting the return air from the air conditioning target room to the indoor air heat exchanger are provided by the return air temperature detecting means. An air conditioner provided with compressor output adjusting means for adjusting the output of the compressor so that the detected return air temperature approaches the target return air temperature, and valve control means for adjusting the opening degree of the electric expansion valve. Regarding

[0002]

2. Description of the Related Art Conventionally, in this type of air conditioner, a valve control means for adjusting the opening degree of an electric expansion valve is used for an indoor air heat exchanger or an outdoor air heat exchanger functioning as an evaporator. The temperature and pressure of the heat medium at the outlet or the inlet of the accumulator are measured, and the degree of superheat is calculated from the temperature and pressure of the heat medium, so that this degree of superheat reaches a predetermined target value. It was configured to adjust the opening of the valve.

[0003]

However, in general, in a heat pump, in order to prevent damage to the circulation path such as a heat exchanger, when the pressure of the circulating heat medium becomes higher than the rated range, In order to prevent the compressor from being damaged due to the so-called high-pressure cut safety device that stops the operation of the compressor and the lubrication effect of the heat medium, the pressure of the circulating heat medium falls below the rated range. If so, a so-called low-pressure cut safety device that stops the operation of the compressor is provided, but according to the above-mentioned conventional technology, the opening degree of the expansion valve is adjusted by changing the operating conditions and operating environment of the air conditioner. In this case, since it is configured to be adjusted based on the temperature and pressure of the heat medium, which is the information that changes as a result, the operating conditions and the operating environment change suddenly. Can not follow the opening degree adjustment in the case, a situation where the high pressure cut-safety devices or low pressure cut safety device is activated there is a disadvantage that the generated opening degree of the expansion valve becomes temporarily significantly incorrect status.

That is, for example, in a heat pump which is operated in heating, when the outside air temperature sharply drops, the capacity of the outdoor air heat exchanger functioning as the evaporator sharply drops and the evaporator pressure decreases. Is significantly reduced temporarily,
The low pressure cut safety device was sometimes activated. In addition, when the heating load of the air-conditioned room increases sharply or the target return air temperature is set rapidly, the output of the compressor increases rapidly and the pressure in the circulation system temporarily increases. There was a case where the high pressure cut safety device was activated due to a significant rise. Further, for example, in a heat pump that is being cooled, when the outside air temperature rises sharply, the capacity of the outdoor air heat exchanger functioning as a condenser sharply decreases, and the condenser pressure temporarily rises. There was a case where the high pressure cut safety device was activated. Also, when the cooling load of the air-conditioned room suddenly increases or the target return air temperature is sharply lowered, the output of the compressor is rapidly increased and the pressure in the circulation system is temporarily increased. There was a case where the high pressure cut safety device was activated due to a significant rise. The present invention is to eliminate the above-mentioned conventional drawbacks.

[0005]

A characteristic configuration of a control device for an electric expansion valve according to the present invention is that the valve control means has a return air temperature, an outside air temperature detected by an outside air temperature detecting means, and a compressor. It is configured to adjust the opening degree of the expansion valve to the target opening degree obtained based on the output.

[0006]

According to the characteristic construction of the present invention, the target opening degree of the expansion valve is obtained based on the temperature of the outside air detected by the return air temperature and the outside air temperature detecting means and the compressor output. Even if the operating conditions and operating environment of the air conditioner change suddenly,
The opening of the expansion valve can be adjusted by directly following these changes.

[0007]

According to the characterizing feature of the present invention, since the adjustment of the opening degree of the expansion valve can be made to follow even when the operating conditions of the air conditioner or the operating environment change drastically, the opening degree of the expansion valve It became a remarkably improper state temporarily, and it became possible to obtain a control device for an electrically driven expansion valve that solved the inconvenience of operating the high pressure cut safety device or the low pressure cut safety device.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an air conditioner that controls the temperature of the air conditioning target room W. The heat pump J is the indoor air heat exchanger 1A.
, Outdoor air heat exchanger 1B, compressor 2, and four-way valve 3
The electric expansion valve 4 and the electric expansion valve 4 are connected to each other by a heat medium pipe 5, and by switching the four-way valve 3, it can be used as an air conditioner for both a heating device and a cooling device. The indoor air heat exchanger 1A is configured by a fin-tube type heat exchanger, and is connected so as to function as a condenser during heating operation and an evaporator during cooling operation.
The return air RA from the air-conditioning target room W is conducted to the indoor air heat exchanger 1A by the return air passage 6 to be temperature-controlled, and then the temperature-controlled air S
A is supplied to the air conditioning target room W through the air supply passage 7.
An air supply fan 8 is provided in the middle of the air supply passage 7. Similarly, the outdoor air heat exchanger 1B is also configured by a fin-tube type heat exchanger, and is connected so as to function as an evaporator during heating operation and a condenser during cooling operation. The outside air OA is conducted to the heat exchanger 1B so as to exchange heat with the outside air. still,
In the middle of the ventilation passage 9 for the outside air OA, the intake side filter 10 is provided.
a, the exhaust side filter 10b, and the outside air ventilation fan 11 are interposed.

In the compressor 2, when the pressure po of the circulating heat medium at the outlet of the compressor 2 becomes higher than the rated range, or when the pressure pi of the circulating heat medium at the inlet of the compressor 2 exceeds the rated range. A high / low pressure cut safety device 12 is provided for stopping the operation of the compressor 2 when it becomes low.

The operation of the heat pump J is controlled by a controller H having a microcomputer as a main part. In the controller H, the return air R returning to the indoor air heat exchanger 1A
A return air temperature sensor 13 as a return air temperature detecting means for detecting the temperature tr of A, and a compressor controller 14 for controlling an output P of the compressor 2 by operating a frequency f of an inverter for controlling the compressor 2 are provided. It is connected and the return air temperature tr approaches the target return air temperature trm based on the detection information of the return air temperature sensor 13 (that is, the room temperature state of the air conditioning target room W is kept constant regardless of the temperature control load change). Thus, the compressor output adjusting means 101 for adjusting the inverter frequency f to adjust the temperature control capability of the heat exchanger 1A as an evaporator is provided.

Further, the controller H further includes an outside air temperature sensor 15 as an outside air temperature detecting means for detecting the temperature to of the outside air OA conducted to the outdoor air heat exchanger 1B, and
An expansion valve controller 4a for operating the opening and closing of the valve of the electric expansion valve 4 is connected, so that the target opening degree Sm of the expansion valve 4 is set based on the return air temperature tr, the outside air temperature to, and the compressor frequency f. A valve control unit 102 for determining and adjusting the expansion valve opening S to the target opening Sm is configured. The target opening Sm is
Determined by table T. The table T is stored in a storage unit (not shown) in the controller H, and a predetermined value can be obtained by selecting the value of the return air temperature tr, the value of the outside air temperature to, and the value of the inverter frequency f. The expansion valve opening degree S can be extracted. The expansion valve opening degree S in the table T is determined to adjust the performance of the expansion valve 4 so that the degree of superheat of the heat pump becomes a predetermined value suitable for its operation. Therefore, the valve control unit 102 adjusts the expansion valve opening degree S to the target opening degree Sm obtained from the table T, so that the superheat degree of the heat pump is maintained at a predetermined value suitable for its operation.

FIG. 2 shows a graph T'representing an example of the table T used in the cooling operation. This graph T ′ is based on the case where the outside air temperature to is 25 ° C. and the return air temperature tr is an arbitrary value,
The relationship between the inverter frequency f and the expansion valve opening S is shown. The inverter frequency f is uniquely determined by the compressor output adjusting means 101 from the relationship between the return air temperature tr and the target return air temperature trm, and therefore the return air temperature tr.
The predetermined target opening degree Sm can be determined from and the inverter frequency f. And the outside air temperature to is higher than 25 ° C.,
Or if it is low, move the graph line up, or
It is sufficient to shift to the lower side and obtain the target opening degree Sm.

FIG. 3 shows a graph T "representing an example of the table T used in the heating operation. The graph T" is shown with the outside air temperature to being 5 ° C. as a reference. Therefore, if the outside air temperature to is higher or lower than 5 ° C., the target opening Sm may be obtained by shifting the graph line to the upper side or the lower side.

[Other Embodiment] The heat pump J is a four-way valve 3
It may be a heating device or a cooling device that does not have the above.

Needless to say, the numerical values shown in FIGS. 2 and 3 are merely examples, and the present invention is not limited to these numerical values.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall configuration of an air conditioner.

FIG. 2 is a graph representing a table for obtaining expansion valve opening degrees.

FIG. 3 is a graph representing a table for determining an expansion valve opening degree.

[Explanation of symbols]

 J Heat pump OA Outside air P Compressor output RA Return air from air-conditioned room SA Temperature controlled air W Air-conditioned room S Electric expansion valve opening Sm Target opening to outside air temperature tr Return air temperature trm Target return air temperature 1A Indoor air heat exchanger 1B Outdoor air heat exchanger 2 Compressor 3 Four-way valve 4 Electric expansion valve 6 Return air passage 7 Supply air passage 13 Return air temperature detecting means 15 Outside air temperature detecting means 101 Compressor output adjusting means 102 Valve control means

Claims (1)

[Claims] 1. An indoor air heat exchanger (1A) and an outdoor air heat exchanger (1B), one of which functions as an evaporator and the other of which functions as a condenser, a compressor (2), and a four-way valve. (3)
And a heat pump (J) provided with an electric expansion valve (4), and the temperature-controlled air (SA) temperature-controlled by the indoor air heat exchanger (1A) is supplied to the air-conditioned room (W). And a return air passage (6) for conducting return air (RA) from the air-conditioned room (W) to the indoor air heat exchanger (1A). Return air temperature (t) detected by the return air temperature detecting means (13)
Compressor output adjusting means (101) for adjusting the output (P) of the compressor (2) so that r) approaches the target return air temperature (trm), and the opening degree () of the electric expansion valve (4). S) adjusting valve control means (102) is provided, wherein the valve control means (102) is the return air temperature (tr).
And the outside air (O) detected by the outside air temperature detecting means (15).
It is configured to adjust the opening degree (S) of the expansion valve (4) to a target opening degree (Sm) obtained based on the temperature (to) of A) and the compressor output (P). air conditioner.