JPH089572Y2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an air conditioner, and more particularly to an air conditioner capable of expanding an air conditioning temperature range.

[Conventional technology]

A conventional air conditioner is configured to include only a cooling unit including a compressor, a condenser, a pressure reducing device, and an evaporator, or a reheating unit. In this air conditioner, a refrigerant that has become a gas in an evaporator is compressed by a compressor, and the compressed refrigerant is condensed in a condenser and converted into a liquid. The liquid refrigerant is evaporated (gasified) in the evaporator, and heat is exchanged with the air ventilated outside the evaporator to cool the air. This cooled air is heated in an air conditioner having a reheat unit and adjusted to a predetermined temperature and humidity.

The amount of refrigerant evaporated in the evaporator is determined by a pressure reducing device installed between the condenser and the evaporator, and a capillary tube is used as one of the pressure reducing devices. The capillary tubes are installed by the number of circuits of the evaporator, and determine the amount of refrigerant to be sent to each circuit. This capillary tube has a simple structure, has no moving parts, is hard to fail, and is inexpensive, and is widely used in a multi-circuit type evaporator because it can accurately distribute a refrigerant to each circuit. Therefore, the air conditioner using the capillary tube is manufactured so that it can be used in a specific air flow rate and temperature range.

[Problems to be solved by the device]

The above conventional air conditioner has the following problems. That is, an expansion valve, a capillary tube, etc. are used in the decompression device, but the capillary tube has a fixed throttling resistance value, so the diameter and length of the tube are selected so as to meet specific operating conditions. ing. Therefore, the air conditioning temperature is within a certain range for a certain air flow rate, for example
It is set in the range of 15 ℃ to 25 ℃ (wet bulb temperature standard).
This air conditioner requires a wider temperature range,
For example, it is used for a temperature and humidity test, and when it is desired to lower the room temperature, frost is formed on the surface of the evaporator, and when it is raised, the suction pressure of the compressor becomes higher than the upper limit suction pressure.

Therefore, the present invention provides an air conditioner capable of solving the inconvenience and expanding the air conditioning temperature range.

[Means for solving the problem]

The present invention is configured as follows to solve the above problems.

That is, the air conditioner has a compressor, a condenser, a capillary tube, and an evaporator, and the evaporator has a multi-circuit configuration in which a refrigerant circuit is divided into a plurality of circuits, and each circuit is orthogonal to the air flow. Capillary tubes having different refrigerant flow rates are attached to the inlet sides of the respective circuits, a temperature or pressure detector is attached to one outlet side of the capillary tube, and the temperature or pressure is attached to the inlet side of another capillary tube. The gist of the present invention is to provide a control valve that is controlled by the detection value of the detector.

[Action]

As described above, the control valve provided on the inlet side of another capillary tube is controlled to be opened / closed appropriately based on the detection value of the detector mounted on the outlet side of one capillary tube for detecting the temperature or pressure. This allows operation in which the evaporation temperature of the refrigerant in the evaporator is equal to or higher than the frosting limit temperature and the suction pressure of the compressor is equal to or lower than the refrigerant temperature corresponding to the upper limit suction pressure. As a result, the air conditioner can operate by setting the air-conditioning temperature to a wider range than before for a specific air amount.

〔Example〕

Embodiments of the present invention are shown in FIGS. 1, 2, 3, and 4.
It will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of an air conditioner having a reheat section, in which a refrigerant gasified by an evaporator 5 is compressed to a high pressure by a compressor 1 and sent to a condenser 2. In the condenser 2, heat is exchanged with the air in the outside air by the condenser fan 3 to liquefy the refrigerant. The liquefied refrigerant is sent to the evaporator 5 via the capillary tube 4 as a pressure reducer. The evaporator 5 can be constructed in multiple circuits (circuits), and in this embodiment, it is constructed in three circuits. Capillary tubes 4a, 4b, 4c are installed corresponding to each circuit between the inlet side of each circuit, that is, between the condenser 5 side and the evaporator 2, and except for one specific circuit, other capillary circuits are installed. The control valves 10b and 10c for adjusting the flow rate of the refrigerant are capillary tubes.
The refrigerant from the condenser 2 is provided on the inlet side of the condensers 4b and 4c (condenser 2 side) and enters the evaporator 5 through the control valves 10b and 10c and the capillary tubes 4a, 4b and 4c. FIG. 2 is an overall perspective view showing an outline of the evaporator 5 having three circuits. Each circuit 30, 31, 32 is formed independently.
That is, in one circuit 30 of the evaporator 5, the end of the finned refrigerant pipe 22 is connected to the outlet side of the capillary tube 4a, and the refrigerant pipe 22 is formed in a meandering manner in the evaporator 5. The other end has an outlet 35 that can be connected to the compressor 1. The other circuits 31 and 32 are also formed in the same manner as the circuit 30. Since the evaporator 5 has the three circuits 30, 31, 32 formed in parallel as described above, the air 15 is orthogonal to each circuit of the evaporator 5 as shown in FIG. The temperature difference with the refrigerant becomes smaller as the air 15 is cooled, so that the evaporation capacity of each circuit becomes a ratio of 1: 0.7: 0.4 for each circuit. Therefore, the respective capillary tubes 4a, 4b, 4c are selected to have different sizes so as to allow a sufficient flow rate of the refrigerant in each circuit to flow. Further, a sensor 7 for detecting the temperature or pressure of the refrigerant is mounted on the outlet side (evaporator 5 side) of the capillary tube 4, and the flow rate of the refrigerant flowing through the evaporator 5 to be described later is determined by the detection value of the sensor 7. Have control. The reason why the control valve is not installed on the inlet side of the capillary tube 4a to which the sensor 7 is attached is that the refrigerant is constantly flown through the capillary tube 4a and the flow rate is adjusted by the other capillary tubes 4b and 4c. The control valve 10 (10b, 1
0c) is an electromagnetic ON / OFF valve. In the evaporator 5, heat is exchanged with the air 15 sent by the evaporator fan 6, that is, the air 15 is cooled, and the cooled air 15 is heated in the reheat section 16. It should be noted that the electric heater is used in this example in which the reheating portion can be heated by steam or the like. Further, the control unit 20 controls the air conditioner by comparing the set room temperature with the temperature detected by the room temperature detector 18.

The refrigerant that has exchanged heat with the air 15 in the evaporator is gasified in the evaporator 5 and sent to the compressor 1.

Next, the operation based on the above configuration will be described with reference to FIGS.
It will be described with reference to the drawings. FIG. 3 shows the control valve 10 for the evaporation temperature of the refrigerant (the temperature detected by the temperature sensor 7) used in this example.
The control section 21 shows the control method for turning on and off b and 10c.
Controlled by. That is, when the temperature detected by the temperature sensor 7 is t1 ° C. or lower, both control valves 10b and 10c are open, and the refrigerant flows through the capillary tubes 4a, 4b, 4c, and when t1 to t2 ° C., the control valve 10b is opened. The refrigerant flows through the capillary tubes 4a and 4b because it is closed at 10c at 10c, and when t2 to t3 ° C, the control valve 10b is closed at 10c.
It means that the refrigerant flows through the capillary tubes 4a and 4c because it is open, and the control valves 10b and 10c are both closed and the refrigerant is controlled to flow only through the capillary tube 4a when t3 ° C. or higher.

In FIG. 4, the horizontal axis shows the evaporation temperature of the refrigerant, the vertical axis shows the evaporation characteristics of the evaporator 5 and the characteristics of the combination of the compressor and the condenser, the solid line shows the conventional performance, and the broken line shows the present example. . Further, the evaporation temperature Ta ° C. of the refrigerant is the limit temperature at which frost adheres to the fins of the evaporator 5, and Tb ° C. is the temperature with respect to the upper limit value of the suction pressure of the compressor.

First, when the air conditioning temperature is set to T3 ° C. (wet bulb standard), the control valve 10b is open and 10c is closed for operation. That is,
As shown in FIG. 3, the refrigerant to the evaporator 5 is supplied through the capillary tubes 4a (the refrigerant always flows because there is no control valve) and 4b, and the temperature of the sensor 7 is t1 ...
It is in the range of t2 ℃. In FIG. 4, the characteristic line M of the combination of the compressor 1 and the condenser 2 and the intersection point A of the evaporation characteristic line m when the refrigerant is supplied to the evaporator 5 via the capillary tubes 4a and 4b. It is being operated in a state. In addition,
In this case, when the air volume of the evaporator fan 6 is constant, the air-conditioning temperature range is based on the intersection point (E, F) of the characteristic line M and the limit temperature Ta to Tb ° C from the limit temperature Ta to Tb ° C of the refrigerant evaporation temperature. From the evaporation characteristic line in), it is the range of T2 ~ T4 ℃.

If the air conditioning temperature is set to be lowered to T1 ° C (lower than the conventional lower limit temperature T2 ° C) in the above condition, the evaporation characteristic line becomes m1 as shown in Fig. 4, and the intersection B of m1 and the characteristic line M
Although it is necessary to perform the operation at the point, the operation at the point B is not desirable because the evaporation temperature of the refrigerant is equal to or lower than the temperature Ta ° C at which frost adheres to the fins of the evaporator 5. That is, this state is because the capacity of the evaporator 5 is insufficient, so that the amount of the refrigerant is increased. Therefore, according to the preset control method shown in FIG. 3 based on the value detected by the sensor 7, the control unit 21 opens the control valves 10b and 10c and evaporates the refrigerant through the capillary tubes 4a, 4b and 4c. Supply to the container 5. The operating state at this time is the air conditioning characteristic line L1 of the evaporator 5 as shown in FIG. 4, the operating state is the intersection point X with the characteristic line M, and the evaporation temperature is the temperature Ta ° C or higher at which frost adheres and is operated. It

Conversely, the air conditioning temperature is higher than T3 ℃ (wet bulb standard) and T5 ℃
A description will be given of setting (wet bulb standard) (higher than the conventional upper limit temperature T4 ° C.) temperature.

As shown in FIG. 4, the evaporation characteristic line is m2, and it is necessary to operate the intersection point C between the m2 and the characteristic line M. At point C, the evaporation temperature is the temperature Tb with respect to the upper limit of the suction pressure of the compressor. ℃
The above is not preferable for operation. That is, this state is because the capacity of the evaporator is large, so that the amount of the refrigerant is reduced. Therefore, according to the control method shown in FIG.
b is closed and control valve 10c is opened. As a result, the refrigerant is supplied to the evaporator 5 via the capillary tubes 4a and 4c.
In the operating state at this time, as shown in FIG. 4, the evaporation characteristic line of the evaporator 5 is L2, the operating state is the intersection point Y with the characteristic line M, and the evaporation temperature is the temperature with respect to the upper limit value of the suction pressure of the compressor. It is operated below Tb ℃.

By making the capacity of the evaporator variable by using the control valve as described above, the evaporation temperature of the refrigerant in the evaporator is increased to the temperature Ta ° C or higher at which frost adheres even if the air conditioning temperature range is expanded, and the compressor is also used. The operation can be performed at a temperature Tb ° C or lower with respect to the upper limit of the suction pressure of.

 The sensor may be detected by pressure instead of temperature.

[Effect of device]

According to the air conditioner of the present invention, since the evaporator has a multi-circuit structure and the amount of the refrigerant flowing in each circuit is controlled with respect to the evaporation temperature of the set refrigerant, air conditioning can be performed in a wider range than the conventional air conditioning temperature range. .

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a general configuration diagram of an air conditioner, Fig. 2 is a schematic overall perspective view of an evaporator, and Fig. 3 is a refrigerant opening / closing operation of a control valve. FIG. 4 is a diagram showing the evaporation temperature of the refrigerant in the evaporator, and FIG. 4 is a graph in which the horizontal axis represents the evaporation temperature of the refrigerant and the vertical axis represents the characteristics of the combination of the compressor and the condenser. 1 ... Compressor, 2 ... Condenser, 4 (4a, 4b, 4c) ... Capillary tube, 5 ... Evaporator, 7 ... Sensor, 10
(10b, 10c) …… Control valve, 30, 31, 32 …… Circuit.

Claims (1)

[Scope of utility model registration request] 1. An air conditioner having a compressor, a condenser, a capillary tube, and an evaporator, wherein the evaporator has a multi-circuit configuration in which a refrigerant circuit is divided into a plurality of circuits, and each circuit is orthogonal to an air flow. And a capillary tube with a different refrigerant flow rate is attached to the inlet side of each circuit, a temperature or pressure detector is attached to one outlet side of the capillary tube, and the temperature is attached to the inlet side of the other capillary tube. Alternatively, an air conditioner characterized in that a control valve controlled by a detection value of a pressure detector is provided.