JPH03267657A - Multi-room air-conditioner - Google Patents

Abstract

PURPOSE:To prevent troubles due to shortage of refrigerant by a method wherein before operation of a variable capacity compressor, a refrigerant saturation pressure and a detection pressure detected by a pressure detector are compared by a saturation pressure detector. CONSTITUTION:An outdoor unit controlling means 16 receives an operation starting command by communication. A saturation pressure detector 13 calculates on the basis of an outdoor air temperature detected by an outdoor air temperature detector 14 a refrigerant saturation pressure corresponding to the detected outdoor air temperature, and provides a calculation result to the outdoor unit controlling means 16. The means 16 obtains at the same time a pressure inside a freezing cycle from a pressure detector 11. Then the means 16 conducts a pressure comparison and a condition discrimination, and if the detected pressure is lower than an outdoor air saturation pressure by a prescribed value, provides an alarm to interrupt the operation. The means 16, if it does not judge any abnormal state in the condition discrimination, provides signals to the room unit controlling means 15 to start its operation, and further controls and starts a fourway valve 3, an outdoor side electric expansion valve 5, an out door fan 6 and an inverter 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the operation control of a multi-room air conditioner, and more particularly to a technique for preventing damage to component equipment due to lack of refrigerant or the like.

BACKGROUND OF THE INVENTION In recent years, individual air conditioning has been progressing in building air conditioning, and as known from Japanese Patent Application Laid-Open No. 1-212870, individual control of multi-room air conditioners has been progressing.

The conventional technology will be described below with reference to the drawings.

1 is an outdoor unit of a multi-room air conditioner, and 2. is a variable capacity compressor.
Four-way valve 3. Outdoor heat exchanger4. An outdoor electric expansion valve 5 and an outdoor fan 6 are installed. 7 are indoor units, four of which are connected in parallel to the outdoor unit 1, each with an indoor electric expansion valve 8. An indoor heat exchanger 9 and an indoor fan 10 are installed. 1
Reference numeral 1 denotes a pressure detector, which is installed in the pipe inside the outdoor unit between the four-way valve 3 and the indoor heat exchanger 9. Reference numeral 12 denotes an inverter that controls the frequency based on the pressure detected by the pressure sensor 11.

The operation of the multi-room outdoor unit configured as above will be explained.

First, in cooling operation, the high-temperature, high-pressure refrigerant discharged from the variable capacity compressor 2 passes through the west valve 8, flows into the outdoor heat exchanger 4, condenses and liquefies, and passes through the outdoor electric expansion valve 5. It is distributed to the indoor unit 7 by piping, is depressurized by the indoor electric expansion valve 8, is evaporated by the 1-side heat exchanger 9, and returns to the variable capacity compressor 2 via the west valve 3 again. Further, during heating operation, the high temperature and high pressure refrigerant discharged from the variable capacity compressor 2 is distributed to each indoor unit via the west valve 3. The refrigerant is condensed and liquefied in the indoor heat exchanger 9 , passed through the indoor electric expansion valve 8 , reduced in pressure by the outdoor electric expansion valve 5 , evaporated in the outdoor heat exchanger 4 , and liquefied through the four-way valve 3 . variable capacity compressor 2
Return to

At this time, the capacity of the variable capacity compressor 2 is determined by the pressure detector 11 at a predetermined pressure based on the detected pressure (evaporating pressure during cooling, condensing pressure during heating) that changes depending on the air conditioning load at that time. This is done by the inverter 12 increasing or decreasing the frequency so that .

Problems to be Solved by the Invention However, in the above configuration, the capacity of the variable capacity compressor is controlled by the refrigerant pressure, so there may be problems such as insufficient amount of refrigerant sealed in the refrigeration cycle during installation or refrigerant leakage from piping. When a refrigerant shortage occurs due to refrigerant shortage, it becomes impossible to control the pressure to a specified level within the compressor's capacity control range, resulting in insufficient capacity.Also, due to the operation due to refrigerant shortage, the variable capacity compressor may overheat, etc. This was a major issue in terms of comfort and reliability, as it caused damage due to

Therefore, the present invention solves the above-mentioned conventional problems by detecting refrigerant shortage, preventing failures due to refrigerant shortage, and
It also makes it easier to identify the cause of a failure and improves serviceability.

Means for Solving the Problem In order to solve this problem, the present invention provides a variable capacity compressor,
An outdoor unit installed with a four-way valve, an outdoor heat exchanger, and an outdoor electric expansion valve, and an indoor unit installed with an indoor electric expansion valve and an indoor heat exchanger, and connected in parallel to the outdoor unit. The outdoor unit is provided with an outdoor unit control means for controlling the operation of the outdoor unit, and a pressure detector and an outside temperature detector for detecting the outdoor temperature are provided in the piping between the four-way valve and the indoor unit, and the detected pressure and The outdoor unit control means consists of an inverter that controls the frequency of the inverter according to the detected temperature, and a saturation pressure detector that detects the refrigerant saturation pressure at the outside temperature before compressor operation. Compare the pressure detected by the saturation pressure of the refrigerant with the pressure detected by the pressure detector before operation of the variable capacity compressor, and if the detected pressure is lower than the saturation pressure by a predetermined pressure, the inverter is not started and the capacity variable is started. It has a configuration in which the compressor does not operate.

Effect of the present invention With the above-described configuration, before operating the variable capacity compressor, the saturation pressure detector compares the refrigerant saturation pressure determined from the outside temperature with the detected pressure detected by the pressure detector, and calculates the refrigerant saturation pressure according to the outside temperature. When the detected pressure is detected to be low due to refrigerant shortage due to refrigerant leakage, etc., and the differential pressure exceeds a predetermined pressure that has a serious effect on the compressor, the compressor will not operate. , to prevent failures.

EXAMPLE An example of the present invention will be described below with reference to the drawings. Components that are the same as the conventional ones are given the same reference numerals and detailed explanations will be omitted. 18 is a saturation pressure detector, which is installed in the outdoor unit. The installed outside temperature detector 14 detects the refrigerant saturation pressure corresponding to the outside temperature detected. Reference numeral 15 denotes an indoor unit control means installed in each indoor unit, which can be operated to start/stop the indoor unit 7, switch between cooling and heating, control the indoor electric expansion valve 8, indoor fan 10, and communicate with the outdoor unit. 16 is an outdoor unit control means,
Through communication from each indoor unit control means 15, the outdoor unit 1 is operated and the inverter 12, four-way valve 3, outdoor electric expansion valve 5, and outdoor fan 6 are controlled.

Next, the operation of the above configuration will be explained.

5TEPI - When the indoor unit control means 14 is operated, the indoor unit control means 14 communicates with the outdoor unit control means 15 and gives the outdoor unit control means 15 information on starting the operation.

5TEP2-The outdoor unit control means 16 receives and takes the command to start operation through communication.

5TEP3-From the outside temperature detected by the outside temperature detector 14,
The saturation pressure detector 13 calculates the refrigerant saturation pressure corresponding to the outside temperature and provides it to the outdoor unit control means 16.

5TEP4-The outdoor unit control means 16 simultaneously obtains the pressure within the refrigeration cycle using the pressure detector 11.

5TEP5-outdoor unit control means 16 is 5TEP3 and 5T
The pressures of EP4 are compared, a condition is determined, and if the detected pressure is lower than the outside air temperature saturation pressure by a predetermined pressure or more, an alarm is issued and subsequent operations are interrupted.

5TEP6-If no abnormality is found in the detected pressure in the condition determination at 5TEP5, the outdoor unit control means 16 not only communicates the start of operation to the indoor unit control means 15, but also controls the four-way valve 3 and the outdoor electric expansion valve 5. , the outdoor fan 6, and the inverter 12, and start operation.

Effects of the Invention As is clear from the above explanation, the multi-room air conditioner according to the present invention has an outdoor unit equipped with a variable capacity compressor, a four-way valve, an outdoor heat exchanger, an outdoor electric expansion valve, and an indoor unit. The indoor unit is equipped with an inner electric expansion valve, an indoor heat exchanger, and is connected in parallel to the outdoor unit, and the outdoor unit includes an outdoor unit control means for controlling the operation of the outdoor unit, and A pressure detector and an outside temperature detector are installed in the piping between the indoor units to detect the outside temperature, and an inverter that controls the frequency of the inverter according to the detected pressure and temperature, and an outside temperature detector that detects the outside temperature before operating the compressor. The outdoor unit control means includes a saturation pressure detector that detects the refrigerant saturation pressure at When the pressures are compared and the detected pressure is lower than the saturation pressure, the inverter is not started and the variable capacity compressor is not operated, so the refrigerant in the air conditioner's refrigeration cycle is If you continue to operate when there is a shortage, it will be possible to prevent a failure that could lead to damage to the compressor due to an excessive rise in the compressor discharge temperature, and the cause of the failure will also become clear. , has great effects on reliability and serviceability.

Note that the present invention applies not only to multi-room air conditioners but also to ordinary air conditioners with one indoor unit and one outdoor unit, as long as they are equipped with a pressure detector and an outside temperature detector. can have the same configuration and have similar effects.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a refrigeration cycle diagram of a multi-room air conditioner that is an embodiment of the present invention, Fig. 2 is a block diagram of the control circuit of Fig. 1, and Fig. 3 is a block diagram of the control circuit of Fig. The control flowchart shown in FIG. 4 is a refrigeration cycle diagram of a conventional multi-room air conditioner. 1... Outdoor unit, 2... Variable capacity compressor, 3... Four-way valve, 4... Outdoor heat exchanger, 5... Outdoor electric expansion valve, 7... Indoor unit, 8 ... Indoor electric expansion valve, 9
・ Converter, 11... Pressure detector, 12. 13... Saturation pressure detector, 14. 15... Indoor unit control means, 16. Stage.

Claims (1)

[Claims] An outdoor unit is installed with a variable capacity compressor, a four-way valve, an outdoor heat exchanger, and an outdoor electric expansion valve, and an indoor electric expansion valve and an indoor heat exchanger are installed, and multiple units are connected in parallel to the outdoor unit. The outdoor unit is equipped with an outdoor unit control means for controlling the operation of the outdoor unit, and a pressure detector and an outside temperature detector for detecting the outdoor temperature are provided in the piping between the four-way valve and the indoor unit. , an inverter that controls the frequency of the inverter according to the detected pressure and temperature, and a saturation pressure detector that detects the saturation pressure of the refrigerant at the outside temperature before compressor operation, and the outdoor unit control means controls the saturation pressure. Compares the saturation pressure of the refrigerant detected by the detector with the pressure detected by the pressure detector before operating the variable capacity compressor, and starts the inverter when the detected pressure is less than the saturation pressure and a predetermined pressure. A multi-room air conditioner in which the variable capacity compressor is not operated.