JPH046351A - Year-round operation type air-cooled chiller unit - Google Patents

Abstract

PURPOSE:To reduce the rotating speed of a fan by an amount corresponding to a decrease in the liquid outlet temperature even when a seasonal wind passes through only one of air-side heat exchangers resulting in a decrease in the liquid outlet temperature, by a method wherein a fan controller modulates the rotating speed of the fan according to the difference between the reduced temperature value of high pressure and the liquid outlet temperature, and two fan controllers are provided to correspond to the air-side heat exchangers on the left and right sides one-to-one. CONSTITUTION:A fan speed controller consists of a signal read-in device 3 which reads signals from a high pressure detecting pick-uip, a signal read-in device 4 which reads signals from a thermistor for detecting the refrigerant outlet temperature, an arithmetic device 5 which calculates the reduced temperatures of the output signal from the read-in device 3 and the predetermined pressure, and the difference between the output signal from the read-in device 4 and the calculated reduced temperature, and a rotating speed controller 6 which controls the rotating speed of a fan according to the output signals from the arithmetic device 5. Air-side heat exchangers 2-1 and 2-2 are respectively provided with a left-side fan 15-1 and a right side fan 15-2 corre sponding to the fan speed controllers 9-1 and 9-2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air-cooled chiller unit that operates year-round, such as a computer cooling device that has a cooling load throughout the year, or a plastic molding machine that requires year-round operation.

[Conventional technology]

The conventional equipment is one Hitachi chiller unit air-cooled screw [
As described in [Service Manual] Blower Group Control, pages 48 to 50, when the outside air temperature is high, the outside air temperature detection thermostat operates all the blowers, and when the outside temperature is low, multiple high-pressure cutoff devices are used to shut down the blowers. The system used only a partial shutdown method to control high pressure.

[Problem to be solved by the invention]

In the above conventional technology, when the seasonal wind is received in winter, when the seasonal wind passes through the air-side heat exchanger, the situation is the same as when the rotation speed of the blower is increased, and the air-side heat exchanger on the side receiving the seasonal wind is compressed. The high temperature, high pressure gas refrigerant from the machine condenses excessively and acts to lower the pressure in the air side heat exchanger and lower the liquid refrigerant temperature. In addition, the high temperature and high pressure gas refrigerant from the compressor becomes too little condensed in the air-side heat exchanger on the 1st side, which receives seasonal winds, increasing the pressure in the air-side heat exchanger and the liquid refrigerant temperature. Operate. However, the inlet sides of the left and right air-side heat exchangers are branched from one pipe from the compressor, and the outlet sides are joined as one liquid pipe, so the pressure inside the left and right air-side heat exchangers is equalized. It becomes pressure. Since only the liquid refrigerant temperatures from the left and right air-side heat exchangers are different, the temperatures of the liquid refrigerants having different temperatures are averaged at the point where the liquid refrigerants meet. If the seasonal wind speed changes here, the pressure fluctuation in the air side heat exchanger,
Fluctuations in liquid refrigerant temperature become large, and the refrigerant condition at the confluence point becomes unstable. No consideration is given to maintaining an appropriate high pressure and liquid refrigerant temperature, and when the outside temperature is low, seasonal winds If only one air side heat exchanger is hit, the compressor and expansion valve that make up the refrigeration cycle will not be able to maintain the minimum required high pressure, lowering the low pressure and going outside the normal refrigeration cycle operating range, resulting in an abnormality due to low pressure cut. There is a stopping problem.

[Means to solve the problem]

In order to achieve the above object, the present invention separately attaches a thermistor for detecting the refrigerant liquid outlet temperature to the liquid outlet piping of the left and right air side heat exchangers, and also installs a thermistor to detect the refrigerant temperature of the left and right air side heat exchangers. A pick amplifier for detecting the high pressure from the machine is installed separately, and the refrigerant outlet temperature and high pressure signals are read simultaneously.If the difference between the value obtained by converting the pressure into temperature and the refrigerant outlet temperature becomes large, it will be detected in proportion to the difference. Fan speed controllers, which have the function of lowering the rotation speed of the blower, are placed one-on-one on the left and right air side heat exchangers.

[Effect]

The fan speed controller, which has one-to-one convection to the left and right air-side heat exchangers, reads the pressure from the refrigerant inlet piping of the air-side heat exchanger via a high-pressure pressure detection pickup, and also reads the pressure from the refrigerant inlet pipe of the air-side heat exchanger through a high-pressure detection pickup. The temperature is read from the outlet piping via the refrigerant liquid outlet temperature detection thermistor, and the value obtained by converting the pre-pressure to temperature is stored in the memory element in the fan speed controller, and the temperature-converted value of this pressure and the thermistor are always detected. It calculates the difference between the temperature of the liquid refrigerant and the temperature of the liquid refrigerant, and controls the rotation speed of the blower.

This controls the fan rotation speed, so even if the seasonal wind passes through only one air-side heat exchanger and lowers the refrigerant liquid outlet temperature, the blower rotation speed will decrease by the amount that the liquid outlet temperature has decreased. As a whole, the air volumes of the left and right air side heat exchangers are balanced, so there is no possibility that the high pressure will drop and go out of the expansion valve control range and malfunction such as a reduction cut.

〔Example〕

Hereinafter, a fan speed controller, which is the central part of the configuration and operation of an embodiment of the present invention, will be explained with reference to FIG. Further, one embodiment of the present invention will be explained with reference to FIG. The fan speed controller constituting the embodiment is the high-pressure pressure detection pickup 1. shown in FIG. Thermistor for detecting refrigerant liquid outlet temperature 2° Signal reading device from pickup for detecting high pressure 3. Signal reading device from the thermistor for detecting refrigerant liquid outlet temperature 4. A calculation device 5 that calculates the difference between the signal output from the reading device 3 and the temperature conversion result of a preset pressure and the signal output from the reading device 4 and the temperature conversion result. It is comprised of a rotation speed control device 6 that receives a signal from a calculation device 5 and controls the rotation speed of the blower. Further, the temperature conversion of preset pressure has characteristics as shown in FIG. The slope line 7 is a pressure direct proportional curve, and the slope line 8 is a curve obtained by converting pressure into temperature. In a region of low pressure, the pressure direct proportional curve human cuff b and the converted temperature output 8b are close to each other, and conversely, in a region of high pressure, these input-output differences 7a-7b are far apart. The degree of closeness of these curves is set to optimize control of the equipment, and the degree is not limited. The fan controller, which has the characteristics of the curve shown in Figure 3, operates to lower the fan rotation speed when the refrigerant outlet temperature is lower than the temperature calculated from the pressure, and the When the temperature matches or approaches that temperature, the fan rotation speed is controlled to a stable constant rotation speed. Conversely, when the outside air temperature rises and the refrigerant liquid outlet temperature is higher than the temperature converted from the pressure, the fan operates to increase the rotation speed, and the refrigerant liquid outlet temperature matches the temperature calculated from the pressure, or It has a function that controls the fan rotation speed to a stable constant rotation speed when the temperature approaches that temperature. A fan controller 9 having this function is installed as a left fan controller 9-1 corresponding to the left air side heat exchanger 1o-1 shown in FIG. Right fan controller 9-2 corresponding to right air side heat exchanger 10-2. The pressure detection pickup is basically connected to the refrigerant inlet piping of the left and right air side heat exchangers, but since there is a slight difference between the left and right air side heat exchangers, it should be pulled out from one place on the compressor 12 or the discharge piping. It works the same way even if it is distributed at the left and right pressure pickup points. The thermistor 2 for detecting the high temperature of the refrigerant liquid is connected to the refrigerant liquid outlet pipe 2-1 for the left air side heat exchanger on the left and right air side heat exchangers.
, is connected as the right air side heat exchanger 2-2.

In addition, the refrigerant liquid outlet pipes from the left and right air side heat exchangers merge into one expansion valve 13. It constitutes a refrigeration cycle that returns from the water cooler 14 to the compressor. Further, the air side heat exchanger includes fan controllers 9-1 and 9-2 and a blower left side 15-1. The right side 15-2 is arranged. The fan controller (7) left side 9-1° and right side 972, which has the above-mentioned function and corresponds one-to-one to left and right air side heat exchange, separately connects the left and right side air blowers 15-1. It is configured to be able to control the right side 15-2, and when the amount of air passing through each air side heat exchanger fluctuates due to the influence of seasonal winds, the amount of variation is detected by the refrigerant liquid outlet temperature of the air heat exchanger. The fan rotation speed is controlled so as to balance the amount of refrigerant condensed in the left and right air-side heat exchangers, and the fluctuations in seasonal winds are absorbed by the fan rotation speed, so that the air volume of the left and right heat exchangers is always balanced. According to the embodiment of the present invention, the refrigerant liquid ratio in the left and right air side heat exchangers is equalized, and high pressure is maintained at low outside temperature.
Effective in preventing low pressure cuts. Also, one fan controller described here is one blower rotation speed control device 6.
This type is capable of controlling the rotation speed of multiple blowers placed on one side, and the fan controller has a plurality of blower rotation speed control devices 6 and can control the rotation speed of multiple blowers placed on one side. Even the available type has the same function as that of the above-mentioned embodiment.

〔Effect of the invention〕

According to the present invention, the total air volume including external factors such as seasonal winds is controlled by constantly detecting and controlling the difference between the pressure of the air volume passing through the left and right air side heat exchangers and the refrigerant outlet temperature. Therefore, when the outside air temperature drops significantly, by balancing the air volume difference between the left and right air side heat exchangers, it is possible to maintain an appropriate high pressure, secure the expansion valve control range, and , has the effect of preventing low pressure cutting.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a fan controller according to an embodiment of the present invention, FIG. 2 is a system diagram of a refrigeration cycle according to the present invention, and FIG.
The figure is a characteristic diagram of pressure and temperature for controlling the rotation speed of the fan controller of FIG. 1. 1. Pickup for high pressure detection, 2. Thermistor for temperature detection, 3. Signal reading device, 4. Signal reading device, 5. Arithmetic device, 6. Blower rotation speed control device. Fan 1st ward

Claims (1)

[Claims] 1. In a refrigeration system comprising a pair of left and right air-side heat exchangers, corresponding left and right blowers, a compressor, an expansion valve, and a water cooler, the high pressure and the refrigerant of the air-side heat exchangers A fan controller that reads the liquid outlet temperature, converts the high pressure into temperature, and controls the rotation speed of the blower based on the difference between the converted temperature value and the refrigerant liquid outlet temperature is connected one-to-one with the left and right air side heat exchangers. This is an air-cooled chiller unit that can be operated throughout the year and is characterized by the provision of two units.