JPH08200773A - Air conditioner - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an air conditioner capable of performing heating operation without using an electric heater at the start of operation of an air conditioner for computer cooling or the like at low temperature such as winter. In an air conditioner having a reheat operation function, a solenoid valve 2 mounted between a discharge side refrigerant pipe of a compressor 1 and a condenser 3 and a thermistor 10 for detecting an indoor temperature.
And a controller 11 for closing the solenoid valve 2 when the temperature detected by the thermistor 10 is lower than a predetermined value at the start of operation of the air conditioner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a reheat operation function, and more particularly to an air conditioner suitable for performing heating operation without using an electric heater at the start of operation of an air conditioner.

[0002]

2. Description of the Related Art A conventional apparatus is disclosed in Japanese Patent Laid-Open No. 62-11934.
As described in Japanese Patent Publication No. 8, an electric heater is mounted on the air conditioner, and when the indoor temperature detected by a temperature sensor or the like is lower than a predetermined value when the air conditioner starts to operate, the electric heater is energized and The heating operation was performed by blowing out warm air.

[0003]

In an air conditioner for cooling a computer or the like, when the computer to be cooled is used at a low temperature, troubles such as dew condensation occur, so that the computer is started at a low temperature such as winter. At this time, an electric heater is mounted on the air conditioner, and the heater is energized to generate warm air by an indoor fan to raise the room temperature.

However, in this method, since the electric heater becomes high in temperature, there is a possibility that the casing may be deformed or damaged due to the heat of the electric heater, or a fire may occur, and in order to prevent the fire, a thermal fuse, a breaker, or the like may be used. Protective equipment needs to be installed. Further, since the electric heater is newly attached, the cost of the entire air conditioner becomes high, and the running cost also becomes high due to the increase in the power consumption for the electric heater and the increase in the contracted electric energy.

It is an object of the present invention to provide an air conditioner capable of performing heating operation without using an electric heater at the start of operation of an air conditioner for computer cooling or the like at low temperature such as winter.

Another object of the present invention is to provide an air conditioner capable of performing heating operation more accurately when the operation of the air conditioner is started.

[0007]

In order to achieve the above object, in an air conditioner having a reheat operation function, a solenoid valve installed between a discharge side refrigerant pipe of a compressor and a condenser and an indoor temperature are controlled. A temperature sensor for detecting and a controller for closing the electromagnetic valve when the temperature detected by the temperature sensor when the operation of the air conditioner is started are lower than a predetermined value are provided.

Further, the electromagnetic valve between the discharge side refrigerant pipe of the compressor and the condenser is closed to start the operation of the air conditioner, and at the same time, the pressure reduction during the cooling operation provided between the condenser and the evaporator. The electric expansion valve for the vehicle was fully closed.

Further, the electromagnetic valve between the discharge side refrigerant pipe of the compressor and the condenser is closed to start the operation of the air conditioner, and at the same time, the pressure reduction during cooling operation provided between the condenser and the evaporator. The electric expansion valve for use was opened for a predetermined time set in advance by the controller, and was fully closed after the predetermined time had elapsed.

Further, a pressure sensor for detecting the pressure of the refrigerant on the discharge side of the compressor is provided, and when the pressure of the refrigerant on the discharge side detected by the pressure sensor is lower than a predetermined value at the start of operation of the air conditioner, the discharge of the compressor is discharged. The electromagnetic valve between the side refrigerant pipe and the condenser is closed to start the operation of the air conditioner, and at the same time, the decompression electric expansion valve for cooling operation, which is provided between the condenser and the evaporator, is previously controlled. It was in an open state for a predetermined time defined in 1. and was in a fully closed state after a lapse of a predetermined time.

Further, a temperature sensor for detecting the outside air temperature around the condenser is provided, and when the outside air temperature detected by the temperature sensor is lower than a predetermined value at the time of starting the operation of the air conditioner, the refrigerant on the discharge side of the compressor is provided. At the same time as starting the operation of the air conditioner by closing the solenoid valve between the pipe and the condenser, the electric expansion valve for pressure reduction during cooling operation provided between the condenser and the evaporator is set in the controller in advance. Open for the given time,
It was put in a fully closed state after a predetermined time had elapsed.

[0012]

In the air conditioner of the present invention, during normal cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor is condensed in the condenser to become the high-temperature and high-pressure liquid refrigerant, which is decompressed by the electric expansion valve. , Forms a low-temperature low-pressure gas refrigerant that evaporates in the evaporator and returns to the compressor via the accumulator to form a refrigeration cycle. A predetermined flow rate of air that is cooled by exchanging heat with the refrigerant when the refrigerant evaporates is drawn into the evaporator, and the cooled air is blown out into the room for cooling.

At the start of operation of the air conditioner, the temperature sensor detects the room temperature and sends it to the controller.
Therefore, the controller closes the solenoid valve when the temperature detected by the temperature sensor is lower than a predetermined value. As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor flows into the auxiliary heat exchanger and is condensed into a high-temperature and high-pressure liquid refrigerant. And
The high-temperature high-pressure liquid refrigerant is decompressed by the flow rate control valve, evaporated in the evaporator to become a low-temperature low-pressure gas refrigerant, and returns to the compressor via the accumulator. Due to the above, the air sucked into the air conditioner is once cooled by the evaporator, but is heated by the auxiliary heat exchanger, and the heating capacity of the auxiliary heat exchanger is larger than the cooling capacity of the evaporator. Therefore, as a result, the air having a temperature higher than the intake air temperature of the air conditioner is blown out, and the heating operation is performed.

Further, the electromagnetic valve between the discharge side refrigerant pipe of the compressor and the condenser is closed to start the operation of the air conditioner, and at the same time, the pressure reduction during the cooling operation provided between the condenser and the evaporator. By fully closing the electric expansion valve for use, the refrigerant is prevented from moving to the condenser side and staying there.

Further, the electromagnetic valve between the discharge side refrigerant pipe of the compressor and the condenser is closed to start the operation of the air conditioner, and at the same time, the pressure reduction during cooling operation provided between the condenser and the evaporator. The electric expansion valve for operation is opened for a predetermined time set in advance by the controller, the refrigerant that has accumulated in the condenser is recovered to the circulation refrigeration cycle within the predetermined time, and after the predetermined time elapses, it is closed. By doing so, on the contrary, the refrigerant does not stay in the condenser.

When the discharge side refrigerant pressure detected by the pressure sensor at the start of operation of the air conditioner is lower than a predetermined value, the refrigerating cycle, particularly the ambient temperature of the condenser is low, and the refrigerant accumulates in the condenser. The electric expansion valve for pressure reduction during cooling operation provided between the condenser and the evaporator was left open for a predetermined time set in advance by the controller and stayed in the condenser. By collecting the refrigerant into the circulation refrigeration cycle within a predetermined time and fully closing the refrigerant after a predetermined time elapses, on the contrary, the refrigerant does not stay in the condenser.

Further, when the outside air temperature detected by the temperature sensor is lower than a predetermined value when the air conditioner starts to operate, it is considered that the ambient temperature of the condenser is low and the refrigerant remains in the condenser. The electric expansion valve for pressure reduction during the cooling operation, which is provided between the evaporator and the evaporator, is kept open for a predetermined time set in advance by the controller, and the refrigerant accumulated in the condenser is set within the predetermined time. By collecting the refrigerant in the circulation refrigeration cycle and fully closing it after a lapse of a predetermined time, on the contrary, the refrigerant does not stay in the condenser.

[0018]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a refrigeration cycle system diagram of the air conditioner of this embodiment, and FIG. 2 is a ph diagram of the refrigeration cycle.

(First Embodiment) As shown in FIG. 1, the air conditioner of this embodiment includes a compressor 1, solenoid valves 2 and 7, a condenser 3, an electric expansion valve 4, an evaporator 5 and an accumulator. The main parts of 6, the auxiliary heat exchanger 8 and the flow rate control valve 9 are sequentially connected by a refrigerant pipe to form a refrigeration cycle. Further, a thermistor 10 which is a temperature sensor for detecting the indoor temperature is provided, and a refrigeration cycle such as receiving a temperature detection signal from the thermistor 10 or outputting to open or close the solenoid valves 2 and 7 is used as a micro cycle. A controller 11 controlled by a computer is provided.

During the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the condenser 3 to become a high-temperature and high-pressure liquid refrigerant, which is decompressed by the electric expansion valve 4 and evaporated by the evaporator 5. To form a low-temperature low-pressure gas refrigerant, and form a refrigeration cycle that returns to the compressor 1 via the accumulator 6. A predetermined flow rate of air, which is cooled by heat exchange with the refrigerant when the refrigerant is evaporated, is sucked into the evaporator 5, and the cooled air is blown out into the room for cooling. In addition, a part of the gas refrigerant discharged from the compressor 1 is branched and passed through the solenoid valve 7,
Heat is condensed in the auxiliary heat exchanger 8 installed in the same ventilation path as the evaporator 5, and heat is exchanged in the auxiliary heat exchanger 8 by the refrigerant flow control valve 9 installed on the refrigerant outlet side of the auxiliary heat exchanger 8. By adjusting the amount and heating the air cooled by the evaporator 5 again, the temperature of air blown from the air conditioner is adjusted.

In this refrigeration cycle, when the air conditioner of this embodiment starts operation, if the room temperature detected by the thermistor 10 is lower than a predetermined value, the controller 11 closes the solenoid valve 2. The solenoid valve 7 is opened and the heating operation is performed. In other words, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is all sent to the solenoid valve 7 side because the electromagnetic valve 2 is closed, and is condensed in the auxiliary heat exchanger 8 to become the high-temperature and high-pressure liquid refrigerant. A refrigeration cycle is formed in which the pressure is reduced by the control valve 9, evaporated in the evaporator 5 to become a low-temperature low-pressure gas refrigerant, and then returned to the compressor 1 via the accumulator 6. The evaporator 5 and the auxiliary heat exchanger 8 draw in a predetermined flow rate of air that exchanges heat with the refrigerant when the refrigerant evaporates and condenses, and the cooled and reheated air is blown out into the room.

Here, the refrigerant refrigeration cycle state in this heating operation is shown on the refrigerant pressure p-enthalpy h diagram in FIG. This figure shows the enthalpy h on the horizontal axis and the refrigerant pressure p on the vertical axis.

In FIG. 2, the change from point 1 to point 2 is the energy of work applied during compression by the compressor 1, and is indicated by the enthalpy difference (h ₂ -h ₁ ). The change from the point 2 to the point 3 is a change of the refrigerant in the auxiliary heat exchanger 8, and is indicated by the enthalpy difference (h ₂ −h ₃ ). The change from point 3 to point 4 is a change in the refrigerant while passing through the flow rate control valve 9, and there is no heat exchange with the outside. The change from the point 4 to the point 1 is the change of the refrigerant in the evaporator 5, and is indicated by the enthalpy difference (h ₁ −h ₃ ). As a result, the auxiliary heat exchanger 8 releases more heat than the evaporator 5 by the amount of work added during compression in the compressor 1.

From the above operation, by closing the solenoid valve 2, it becomes possible for the air conditioner to obtain a blown air temperature higher than the room temperature, and the room temperature drops when the air conditioner is started. If so, heating operation can be performed.

(Second Embodiment) In addition to the configuration of the first embodiment,
At the same time as closing the solenoid valve 2 when starting the air conditioner,
The controller 11 commands the electric expansion valve 4 to be fully closed. This makes it possible to prevent the refrigerant from flowing into the condenser 3 during the heating operation, and to prevent the refrigerant in the heating operation refrigeration cycle from becoming insufficient due to the refrigerant remaining in the condenser 3.

(Third Embodiment) In addition to the configuration of the first embodiment,
At the same time as closing the solenoid valve 2 when starting the air conditioner,
The controller 11 commands the electric expansion valve 4 to be fully closed after being left open for a predetermined time. As a result, when the refrigerant has already accumulated in the condenser 3 when the air conditioner is started up, it becomes possible to recover the refrigerant in the heating operation refrigeration cycle, and then the electric expansion valve 4 is fully closed. By doing so, it is possible to prevent a shortage of the refrigerant in the heating operation refrigeration cycle due to the refrigerant flowing toward the condenser 3 during the heating operation and the refrigerant staying in the condenser 3.

(Fourth Embodiment) In this embodiment, in addition to the structure of the first embodiment, a pressure sensor 12 for detecting the refrigerant discharge pressure of the compressor 1 is provided. Here, when the discharge side refrigerant pressure detected by the pressure sensor 12 is lower than a predetermined value at the time of starting the operation of the air conditioner, the refrigeration cycle, particularly the ambient temperature of the condenser 3 is low, and the refrigerant stays in the condenser 3. Therefore, the pressure-reducing electric expansion valve 4 provided between the condenser 3 and the evaporator 5 during the cooling operation is opened for a predetermined time set in advance by the controller 11, and the condenser 3 Refrigerant that has stayed inside is collected in the circulation refrigeration cycle within a predetermined time, and is fully closed after a predetermined time elapses.
Since the refrigerant does not stay inside, it is possible to prevent the refrigerant in the heating operation refrigeration cycle from running out.

(Fifth Embodiment) In this embodiment, a temperature sensor 13 for detecting the outside air temperature around the condenser 3 is provided in addition to the structure of the first embodiment. Here, when the outside air temperature detected by the temperature sensor 13 at the start of operation of the air conditioner is lower than a predetermined value, the refrigerating cycle, particularly the ambient temperature of the condenser 3 is low, and the refrigerant stays in the condenser 3. Thinking,
The decompression electric expansion valve 4 provided between the condenser 3 and the evaporator 5 during the cooling operation is kept open for a predetermined time set in advance by the controller 11 and remains in the condenser 3. The refrigerant is collected in the circulation refrigeration cycle within a predetermined time and is fully closed after the predetermined time elapses, so that the refrigerant does not stay in the condenser 3 conversely. It can prevent shortage.

[0030]

According to the invention described in claim 1 of the present invention described above, it is possible to perform a highly safe heating operation without using an electric heater, and to provide an auxiliary heat exchanger for reheat operation. Since it can be used as it is, compared to the case where an electric heater is used, the electric heater can be omitted, so that the facility and the protection device can be simplified, and thus the cost of the entire air conditioner can be reduced. Since there is no need for power consumption and contract power for the electric heater, there is an effect that running cost can be reduced.

In addition, claims 2, 3, 4 and 5 of the present invention.
According to the described invention, there is an effect that the heating operation can be executed more accurately when the operation of the air conditioner is started.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle system diagram showing an embodiment of an air conditioner of the present invention.

FIG. 2 is a ph diagram of the air conditioner of the present invention.

[Explanation of symbols]

1 ... Compressor, 2 ... Solenoid valve, 3 ... Condenser, 4 ... Electric expansion valve, 5 ... Evaporator, 6 ... Accumulator, 7 ... Solenoid valve, 8
... Auxiliary heat exchanger, 9 ... Flow control valve, 10 ... Thermistor,
11 ... Controller, 12 ... Pressure sensor, 13 ... Temperature sensor.

Claims (5)

[Claims] 1. A compressor, a condenser, an electric expansion valve, an evaporator and an accumulator are sequentially circulated and connected by a refrigerant pipe to form a cooling and refrigeration cycle, and a predetermined amount of air is sent to the evaporator by a blower. Along with cooling, a part of the gas discharged from the compressor is branched and condensed in an auxiliary heat exchanger installed in the same ventilation path as the evaporator, and installed on the refrigerant outlet side of the auxiliary heat exchanger. By adjusting the amount of heat exchange in the auxiliary heat exchanger by the refrigerant flow rate adjusting valve and reheating the air cooled in the evaporator, there is a reheat operation function of adjusting the temperature of air blown out from the air conditioner. In the air conditioner, a solenoid valve installed between the discharge side refrigerant pipe of the compressor and the condenser, a temperature sensor for detecting the room temperature, and a temperature detected by the temperature sensor at the start of operation of the air conditioner are An air conditioner comprising a controller for closing the solenoid valve when the value is lower than a predetermined value. 2. The air conditioner according to claim 1, wherein the electromagnetic valve between the discharge side refrigerant pipe of the compressor and the condenser is closed to start the operation of the air conditioner, and at the same time, between the condenser and the evaporator. An air conditioner characterized in that an electric expansion valve for pressure reduction provided during cooling operation is fully closed. 3. The air conditioner according to claim 1, wherein the electromagnetic valve between the discharge side refrigerant pipe of the compressor and the condenser is closed to start the operation of the air conditioner, and at the same time, between the condenser and the evaporator. An air conditioner characterized in that an electric expansion valve for decompression provided during cooling operation is opened for a predetermined time set in advance by a controller and is fully closed after a lapse of the predetermined time. 4. The air conditioner according to claim 1, further comprising a pressure sensor for detecting a discharge side refrigerant pressure of the compressor, wherein the discharge side refrigerant pressure detected by the pressure sensor is greater than a predetermined value when the air conditioner starts to operate. If it is low, the solenoid valve between the compressor discharge side refrigerant pipe and the condenser is closed to start the operation of the air conditioner, and at the same time, the pressure reduction during cooling operation provided between the condenser and the evaporator. An air conditioner characterized in that an electric expansion valve for use is opened for a predetermined time set in advance by a controller and is fully closed after a predetermined time has elapsed. 5. The air conditioner according to claim 1, wherein a temperature sensor for detecting an outside air temperature around the condenser is provided, and the outside air temperature detected by the temperature sensor is lower than a predetermined value when the air conditioner starts to operate. In addition, the electromagnetic valve between the compressor discharge side refrigerant pipe and the condenser is closed to start the operation of the air conditioner, and at the same time, the decompression electric power is installed between the condenser and the evaporator during the cooling operation. An air conditioner, wherein the expansion valve is opened for a predetermined time set in advance by a controller, and is fully closed after a predetermined time has elapsed.