JPS60202276A - Air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is directed to cooling and cooling air directly by an evaporator of a chiller.
The present invention relates to an air conditioner that dehumidifies.

[Background of the invention]

In general, an air conditioner using a refrigerator uses an automatic expansion valve to adjust the flow rate of refrigerant sent to the evaporator according to the degree of superheat at the outlet of the evaporator. An automatic evaporation pressure control valve is provided.1 By adjusting this valve, the evaporation pressure of the evaporator is controlled and the temperature of the evaporator is controlled.

In order to increase the efficiency of this air conditioner, it is necessary to operate it in accordance with the cooling load. If there is a temperature difference (0C) between the evaporator inlet air temperature and the set temperature (outlet air temperature), the cooling load Qz is given by the following equation.

Qt= G X Cp X △f (Kod / A
) Here, CP: Specific heat of air (K,,g,/h-C
) G: Detention (K9/, A) On the other hand, the cooling capacity Qc is given by the following formula.

Qc = Cx V (Ka< /n) where ■: Compression amount (Kp/h) C: Constant Therefore, it is possible to save the operation so that the cooling valve stay 'Q' and the cooling capacity Qc match. It turns out that it is advantageous in terms of energy.

An example of a conventional air conditioner is shown in FIG. The refrigerator consists of a compressor 1, a condenser 2, and an evaporator 4 connected through a refrigerant pipe 6 to form a refrigeration cycle. The refrigerant flow rate is controlled by the provided variable expansion valve 3, while the evaporation pressure of the evaporator is adjusted by the evaporation pressure control valve 5 provided in the pipe connecting the evaporator 4 and the compressor 1. The temperature of the container is controlled. The automatic expansion valve 3 detects the temperature of the refrigerant gas flowing out from the evaporator 4 with a temperature sensor 20, and adjusts the opening degree according to the refrigerant gas temperature. On the other hand, the opening degree of the evaporation pressure control valve 5 is adjusted according to the pressure of the refrigerant gas flowing out from the evaporator. Note that 11 is a blower.

However, according to the above configuration, the automatic expansion valve 3 can be controlled relatively well at the rated load, but when the load is 1.
When the weight is reduced to about 1/2, the heat necessary for evaporating the liquid refrigerant is not easily applied from the outside, and the change in the temperature of the refrigerant gas flowing out from the evaporator becomes small. Normally, when the temperature difference in an expansion valve becomes small, the spring or diaphragm exceeds the elastic range, resulting in a decrease in controllability. Therefore, it becomes difficult to control the expansion valve in accordance with the outside temperature, that is, to control the temperature of the evaporator with high precision, and the air is supercooled.

As an example of this measure, as shown in Fig. 1, a heater 7 is placed in front of the evaporator, the outlet temperature is measured with a temperature sensor 8 provided on the outlet side, and the temperature is adjusted to keep this outlet temperature constant. The heater is controlled to be energized via a total of 9 and a thyristor 10. This method does not consume extremely wasteful energy of heating the cooled air again with a heater to reach the desired air temperature.
It is uneconomical.

Furthermore, a cooling device has been proposed in which the evaporation pressure control valve is adjusted based on the temperature of the evaporator without using a heater.

(Japanese Unexamined Patent Publication No. 52-618581) This device detects the temperature of the evaporator with a temperature sensor, compares the temperature of the evaporator with a set temperature using a comparator, and then calculates the evaporation pressure based on the deviation signal at this time. This is to adjust the control valve.

However, since the compressor used in this cooling device is operated regardless of the load, there is a problem in that the mechanical wear of the rotation and parts is severe and the life of the compressor is shortened.

[Purpose of the invention]

An object of the present invention is to provide an air conditioner that controls a compressor and an evaporator according to the cooling load, eliminates wasteful energy consumption, and makes it easy to change the set temperature.

[Summary of the invention]

The air conditioner of the present invention is equipped with a controller that controls the rotation speed of the compressor based on the room temperature, and an evaporation pressure control valve that controls the evaporation pressure of the evaporator. The rotation speed of the evaporator is lowered to reduce the capacity of the compressor, and the evaporator pressure regulating valve 1 is throttled to increase the temperature of the evaporator.As a result, the air temperature on the outlet side of the evaporator is controlled to be increased, and the cooling load is increased. The refrigerator is controlled accordingly.

[Embodiments of the invention]

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

In FIG. 2, parts and devices that are the same as those in FIG. 1 are designated by the same reference numerals and their explanations will be omitted.

A compressor 1, a condenser 2, and an evaporator 4 are connected via a refrigerant pipe 6 to form a refrigeration cycle, and a refrigerant liquid is supplied to the pipe connecting the condenser 2 and the evaporator 4. A capillary tube 12 for low pressure/low temperature pressure is provided, and an automatic evaporation pressure control valve 13 for keeping the evaporation pressure of the evaporator 4 constant is interposed in a conduit connecting the compressor 1 and the evaporator 4.

The evaporator 4 is installed in a wind barrel 18, and at the inlet of the wind barrel there is an inlet air temperature sensor 14' for measuring the room temperature, and at its outlet there is an outlet air temperature sensor 14' for measuring the temperature of the air cooled by the evaporator 4. A temperature sensor 58 is arranged.

Each temperature sensor 8.14 is connected to a temperature controller 9.15, which outputs the manipulated variable of the controlled object based on the difference from the set temperature. The xyrisk 10 controls the automatic evaporation pressure control valve 13 to an opening degree commensurate with the operation amount, and the rotation speed controller 16 controls the difference between the room temperature and the set temperature, as shown by the solid line in FIG. Temperature difference (cooling load)
The rotation speed of the compressor is controlled in stages according to the

Next, the operation of the embodiment of the present invention will be explained.

Room temperature is detected by an inlet air temperature sensor 14, and this inlet air temperature is compared with a set temperature by a first temperature controller 15. The temperature difference at this time is proportional to the cooling load. Therefore, in the first temperature controller 15, an electrical operation amount is created to obtain the rotation speed of the compressor commensurate with the cooling load, and this operation amount is used in the rotation speed controller 16 to generate the electric power necessary to drive the compressor 1. output. Then, the compressor is controlled to the optimum rotation speed corresponding to the cooling load based on the output. Note that the manipulated variable includes control information for increasing or decreasing the rotation speed of the compressor in stages with respect to the cooling capacity ratio. Subsequently, the outlet air temperature detected by the temperature sensor 8 is input to the second temperature controller 9, where it is compared with the set temperature. In this second temperature controller 9, a valve operation amount is created from the temperature difference to obtain the opening degree of the evaporation pressure control valve 13 so that the evaporation pressure of the evaporator becomes constant, and this valve operation amount is applied to the thyristor. It is converted into the electrical output necessary to drive the valve. In this way, the evaporation pressure of the evaporator is controlled by the outlet air temperature, and the temperature change inside the evaporator based on this evaporation pressure is regarded as an i change in the outlet air temperature, and the temperature difference between the changed outlet air temperature and the set temperature is The opening degree of the evaporation pressure regulating valve 13 is feedback-controlled until it becomes zero.

In the above embodiment, the rotation speed of the compressor is adjusted to control the cooling capacity within a certain range, and the evaporation pressure control valve is linearly adjusted within that range, so there is no risk of knocking in the control system. , the outlet air temperature to be controlled can be stably controlled.

In addition, if the above-mentioned problem does not exist, the compressor and the evaporation pressure control valve can be linearly controlled at the same time (indicated by the chain line in FIG. 3).

In addition, by changing the setting value of the temperature controller to obtain the desired outlet air temperature, that is, the optimum room temperature, the compressor and automatic evaporation pressure control valve can be feedback-controlled based on the temperature difference between the inlet and outlet sides of the evaporator. Moreover, the compressor can be operated optimally according to the cooling load at that time.

Note that although the above embodiments have described control related to temperature, similar control is possible for humidity as well.

Furthermore, evaporation pressure? The J4m valve uses a bimetallic control valve, an electric valve, an air-operated valve, etc. that controls the heating of the bimetal according to an input signal and moves the valve body up and down to adjust the opening area.

〔Effect of the invention〕

As described above, according to the present invention, when the cooling load is reduced, the flow rate of refrigerant supplied to the evaporator is reduced and the rotational speed of the compressor is controlled to be lowered, so that it is possible to prevent insufficient air. , it is possible to eliminate wasteful consumption of energy and perform efficient air conditioning operation. In addition, you can easily obtain the desired room temperature by simply changing the temperature setting on the temperature controller.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional air conditioner, Fig. 2 is a schematic diagram of an air conditioner according to the present invention, and Fig. 3 is a diagram of the relationship between compressor rotation speed and cooling capacity ratio applied to the present invention. , FIG. 4 is a diagram showing the relationship between the opening degree of the evaporation pressure regulating valve and the temperature inside the evaporator. 1... Compressor, 2... Condenser, 4... Evaporator, 1
3... Evaporation pressure control valve, 16... Rotation speed controller. Agent Tatsuyuki Unuma (and 1 other person) Figure 1 Figure 2

Claims (2)

[Claims] (1) In an air conditioner using a refrigerator, in which a compressor, a condenser, and an evaporator are sequentially connected through refrigerant piping to form a refrigeration cycle, an evaporation pressure regulating valve is installed in the refrigerant piping connecting the evaporator and compressor. An air conditioner further comprising a controller for controlling the rotation speed of the compressor according to room temperature, and controlling the evaporation pressure of the evaporator and the rotation speed of the compressor according to the cooling load. (2) The air conditioner according to claim 1, wherein the evaporation pressure regulating valve is controlled by the air temperature on the outlet side of the evaporator.