JP2002228274A - Refrigerating device and air conditioner using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating device to enable prevention of overheating of the discharge refrigerant of a compressor even when various abnormalities occur. SOLUTION: In the refrigerating device where a compressor, a condenser, an expansion valve, and an evaporator are interconnected, in the order, through refrigerant piping and control of the opening of the expansion valve is effected based on a refrigerant temperature difference between the inlet and the outlet of the evaporator, control of the opening of the expansion valve is corrected according to the refrigerant discharge temperature of the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration apparatus and an air conditioner using the refrigeration apparatus.

[0002]

2. Description of the Related Art Conventionally, this type of refrigeration apparatus detects the difference in refrigerant temperature between the inlet and outlet of an evaporator regardless of the refrigerant discharge temperature of a compressor and adjusts the opening of an expansion valve to overheat the refrigerant discharged from the compressor. Prevention control was being performed.

[0003]

However, when various abnormalities occur in the refrigeration system, there are cases where overheating of the refrigerant discharged from the compressor cannot be prevented.

Therefore, the present invention has been made in consideration of the above points,
An object of the present invention is to provide a refrigeration apparatus (air conditioner) that can prevent overheating of refrigerant discharged from a compressor even when various abnormalities occur.

[0005]

According to a first aspect of the present invention, a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe, and a refrigerant temperature difference between an inlet and an outlet of the evaporator. In the refrigerating apparatus that controls the opening degree of the expansion valve based on the above, the control of the opening degree of the expansion valve is corrected according to the refrigerant discharge temperature of the compressor.

The invention according to claim 2 is characterized in that when the refrigerant discharge temperature of the compressor is higher than a predetermined value, the valve opening of the expansion valve is corrected in the opening direction.

According to a third aspect of the present invention, when the refrigerant discharge temperature of the compressor is lower than a predetermined temperature, the valve opening of the expansion valve is corrected in the closing direction.

The invention according to claim 4 is characterized in that a living space is air-conditioned by a refrigeration system.

According to a fifth aspect of the present invention, in the air conditioner, the flow of the refrigerant discharged from the compressor is reversed to perform the cooling / heating operation, and the air conditioner acts as an expansion valve during the cooling operation. The valve is provided near the indoor heat exchanger that functions as an evaporator, and the electric expansion valve that functions as an expansion valve during the heating operation is provided near the outdoor heat exchanger that functions as a condenser.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram of an air conditioner showing an embodiment of the present invention.

As shown in FIG. 1, an air conditioner (refrigeration apparatus) 1 has an outdoor unit 2 and an indoor unit 3.
The refrigerant pipe 4 of the indoor unit 3 is connected to the refrigerant pipe 5 of the indoor unit 3 by a pipe 50 between the units.

The outdoor unit 2 includes a compressor 7, a four-way switching valve 8,
An outdoor heat exchanger 9 and an outdoor expansion valve 10 are provided.
The compressor 7 is provided with a temperature sensor 16A for detecting a gas refrigerant temperature at a discharge pipe thereof. The outdoor heat exchanger 9 is provided with a temperature sensor 16C for detecting the refrigerant temperature in the middle of the refrigerant pipe and a temperature sensor 16E for detecting the refrigerant temperature at the outlet of the refrigerant pipe during the cooling operation. Outdoor fan 9F that draws in outside air toward the vessel 9
Is disposed adjacent to the outdoor heat exchanger 9.

The indoor unit 3 is provided with an indoor heat exchanger 11 and an indoor expansion valve 12. The indoor heat exchanger 11 includes:
A temperature sensor 16G for detecting a refrigerant temperature at an inlet of the refrigerant pipe during the cooling operation, a temperature sensor 16H for detecting a refrigerant temperature at an outlet of the refrigerant pipe during the cooling operation, and a temperature for detecting the refrigerant temperature in the middle of the refrigerant pipe. A sensor 16J is provided, and an indoor fan 11F for blowing air to the indoor heat exchanger 11 is provided adjacent to the indoor heat exchanger 11.

Reference numeral 15 denotes a control device of the air conditioner 1, which controls the four-way switching valve 8, the outdoor fan 9F, the outdoor expansion valve 10, the indoor fan 11F, the indoor expansion valve 12, and the like. Control device 15
, A, B, C, D, E, F, G, H,
J, K, and L represent wiring to each member controlled by the control device 15, and include a temperature sensor 16A, a four-way switching valve 8, a temperature sensor 16C, an outdoor expansion valve 10, and a temperature sensor 16 respectively.
E, an outdoor fan 9F, a temperature sensor 16G, a temperature sensor 16H, a temperature sensor 16J, an indoor expansion valve 12, and an indoor fan 11F.

In the air conditioner 1, the flow of the refrigerant flowing through each of the refrigerant pipes 4 and 5 is changed by switching the four-way switching valve 8, and the cooling operation or the heating operation is performed.

During the cooling operation, the four-way switching valve 8 is switched to the cooling side, and the refrigerant flows through the refrigerant pipes 4 and 5 as shown by solid arrows in FIG. 1, the outdoor expansion valve 10 is opened, and the outdoor heat exchanger 9 is condensed. The indoor expansion valve 12 is controlled as a throttle valve, the indoor heat exchanger 11 is operated as an evaporator, and the indoor unit 1 cools the room.

During the heating operation, the four-way switching valve 8 is switched to the heating side, and the refrigerant flows through each of the refrigerant pipes 4 and 5 as shown by the broken arrows in FIG. 1, and the outdoor expansion valve 10 is controlled as a throttle valve to control the outdoor heat. The exchanger 9 functions as an evaporator, the indoor expansion valve 12 is opened, the indoor heat exchanger 11 functions as a condenser, and the indoor unit 1 heats the room.

Conventionally, the air conditioner 1 detects the difference between the inlet and outlet refrigerant temperatures (.DELTA.E) of the evaporator (the indoor heat exchanger 11) during the cooling operation, regardless of the refrigerant discharge temperature of the compressor 7, and calculates the .DELTA.E
Is small, the valve opening of the indoor expansion valve 12 is adjusted in the closing direction, and if ΔE is large, the valve opening of the indoor expansion valve 12 is adjusted in the opening direction to prevent the refrigerant discharged from the compressor 7 from overheating. Control.

However, when the air conditioner 1 is operated under various conditions, it may not be possible to prevent the refrigerant discharged from the compressor 7 from being overheated.

Therefore, the present invention has been made in consideration of the above points,
Optimal control of the indoor expansion valve 12 is performed in consideration of the state of the refrigerant temperature discharged from the compressor 7 as described below.

Here, the details of the present invention will be described with reference to FIG. FIG. 2 is a flowchart of the overheat prevention control of the air conditioner according to the embodiment of the present invention.

During the cooling operation, the air conditioner 1 performs the refrigerant temperature difference (Δ) detected by the temperature sensors 16H and 16G provided at the entrance and exit of the refrigerant pipe of the indoor heat exchanger 11 (evaporator).
When E) is larger than the predetermined value, the overheat prevention control of the refrigerant circuit of the air conditioner 1 is performed. (For example, overheat prevention control is performed when ΔE> 6 ° C) (S1).

If the above-described overheat prevention control is not performed, normal target discharge temperature control is performed (S2). This target discharge temperature control is a control for opening and closing the indoor expansion valve 12 so as to guide the actual discharge refrigerant temperature to the target discharge temperature determined in consideration of the condensation temperature and the evaporation temperature of the refrigerant detected by the temperature sensors 16C and 16J. It is.

When performing the above-described overheat prevention control, first, a temperature sensor 16 provided at the outlet refrigerant pipe of the compressor 7 is used.
The refrigerant discharge temperature is detected by A (S3). If the refrigerant discharge temperature is in the normal range, the overheat prevention control based on the refrigerant temperature difference between the inlet and the outlet of the evaporator as described below is performed as in the conventional case (S
5).

For example, during the cooling operation, the indoor heat exchanger 11
When the inlet / outlet refrigerant temperature difference (ΔE) of the (evaporator) is under the following condition, the opening degree of the indoor expansion valve 12 is adjusted as follows.

When 6 ° C = <ΔE <10 ° C: Opening (after adjustment) = Opening (before adjustment) × 1.1 times When 10 ° C = <ΔE <15 ° C: Opening ( After adjustment)
= Opening (before adjustment) x 1.2 times 15 ° C = <ΔE: opening (after adjustment)
= Opening (before adjustment) x 1.3 times In this way, the degree of superheat of the refrigerant at the outlet of the evaporator is reduced to 6
Adjust to less than ゜ C.

Here, when the refrigerant discharge temperature is lower than a predetermined value (for example, the condensing temperature + 15 ° C.), the following overheat prevention control based on the refrigerant temperature difference between the inlet and the outlet of the evaporator is performed (S).
4).

When 6 ° C = <ΔE <10 ° C: opening (after adjustment) = opening (before adjustment) × 1.05 times When 10 ° C = <ΔE <15 ° C: opening ( After adjustment)
= Opening (before adjustment) x 1.1 times 15 ° C = <ΔE: Opening (after adjustment)
= Opening degree (before adjustment) x 1.15 times In this way, when the temperature of the refrigerant discharged from the compressor 7 is lower than a predetermined value (for example, the condensation temperature + 15 ° C), the amount of adjustment of the opening degree of the expansion valve is corrected in the closing direction. Therefore, it is possible to cope with a cause of a decrease in the temperature of the discharged refrigerant (for example, poor branch flow) without increasing the circulation amount of the refrigerant so much.

Here, the refrigerant discharge temperature is set to a predetermined value (for example, 90
If the temperature is higher than ゜ C), the following overheat prevention control is performed based on the difference between the refrigerant temperatures at the inlet and outlet of the evaporator (S6).

When 6 ° C = <ΔE <10 ° C: opening (after adjustment) = opening (before adjustment) × 1.2 times When 10 ° C = <ΔE <15 ° C: opening ( After adjustment)
= Opening (before adjustment) x 1.4 times 15 ° C = <ΔE: Opening (after adjustment)
= Opening degree (before adjustment) x 1.6 times In this way, when the temperature of the refrigerant discharged from the compressor 7 is higher than a predetermined value (for example, 90 ° C), the amount of adjustment of the opening degree of the expansion valve is corrected in the opening direction and the refrigerant is opened. It is possible to cope with an increase in the discharge refrigerant temperature (for example, a high load) by increasing the circulation amount of the refrigerant.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, in the above embodiment, the air conditioner 1 including the outdoor unit 2 and the indoor unit 3 has been described, but it goes without saying that the air conditioner may be an integrated air conditioner or a refrigerator such as a refrigerator.

[0032]

As described above, according to the first aspect of the present invention, the compressor, the condenser, the expansion valve, and the evaporator are sequentially connected by the refrigerant pipe, and based on the refrigerant temperature difference between the inlet and the outlet of the evaporator. In a refrigeration system that performs valve opening control of an expansion valve,
It is possible to provide a refrigeration apparatus that can prevent overheating of the refrigerant discharged from the compressor by correcting the valve opening control of the expansion valve according to the refrigerant discharge temperature of the compressor.

According to the second aspect of the present invention, when the refrigerant discharge temperature of the compressor is higher than a predetermined value, the valve opening of the expansion valve is corrected in the opening direction, thereby overheating the refrigerant discharged from the compressor. Providing a refrigeration device that can be prevented can be provided.

According to the third aspect of the invention, when the refrigerant discharge temperature of the compressor is lower than the predetermined temperature, the degree of opening of the expansion valve is corrected in the closing direction to thereby reduce the overheating of the refrigerant discharged from the compressor. Providing a refrigeration device that can be prevented can be provided.

According to the fourth aspect of the present invention, it is possible to provide a refrigeration apparatus capable of preventing overheating of the refrigerant discharged from the compressor by air-conditioning the living space by the refrigeration apparatus.

According to the fifth aspect of the present invention, the air conditioner reverses the flow of the refrigerant discharged from the compressor so as to perform the cooling / heating operation, and also functions as an expansion valve during the cooling operation. An electric expansion valve is provided near an indoor heat exchanger that acts as an evaporator, and an electric expansion valve that acts as an expansion valve during its heating operation is provided near an outdoor heat exchanger that acts as a condenser. It is possible to provide a refrigeration apparatus that can prevent overheating of the discharged refrigerant.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an air conditioner showing an embodiment of the present invention.

FIG. 2 is a flowchart of overheat prevention control of the air conditioner according to the embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 air conditioner 2 outdoor unit 3 indoor unit 7 compressor 8 four-way switching valve 9 outdoor heat exchanger 10 outdoor expansion valve 11 indoor heat exchanger 12 indoor expansion valve 15 controller 16A, 16C, 16E, 16G, 16H, 16J sensor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuo Tajima 1 Otsukicho, Ashikaga, Tochigi Prefecture Sanyo Electric Air Conditioning Co., Ltd. (72) Inventor Kiyoshi Tamura 1 Otsukicho, Ashikaga, Tochigi Prefecture Sanyo Electric Air Conditioning Co., Ltd. (72) Inventor Tamura ▲ Yoshi ▼ Hisashi Sanyo Electric Air Conditioning Co., Ltd. 1 Otsuki-cho, Ashikaga City, Tochigi Prefecture (72) Inventor Seiichi Koga 1 Otsuki Town, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning Co., Ltd. F-term (Reference) 3L060 AA02 CC04 DD02 EE09 3L092 AA11 BA23 DA14 EA03 EA05 EA20 FA27

Claims (5)

[Claims] 1. A refrigeration apparatus in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe, and a valve opening degree of the expansion valve is controlled based on a refrigerant temperature difference between an inlet and an outlet of the evaporator. A refrigerating apparatus, wherein the valve opening control of the expansion valve is corrected according to a refrigerant discharge temperature of the compressor. 2. The refrigeration system according to claim 1, wherein when the refrigerant discharge temperature of the compressor is higher than a predetermined value, the valve opening of the expansion valve is corrected in the opening direction. 3. The refrigeration apparatus according to claim 1, wherein when the refrigerant discharge temperature of the compressor is lower than a predetermined temperature, the valve opening of the expansion valve is corrected in a closing direction. 4. An air conditioner, wherein a living space is air-conditioned by the refrigerating device according to claim 1. 5. The air conditioner reverses the flow of the refrigerant discharged from the compressor so as to perform a cooling / heating operation, and includes an electric expansion valve that functions as an expansion valve during the cooling operation. 5. An electric expansion valve which is provided in the vicinity of an indoor heat exchanger functioning as a heat exchanger and which functions as an expansion valve during a heating operation thereof is provided in the vicinity of an outdoor heat exchanger which functions as said condenser.
The air conditioner according to item 1.