Multiple type air conditioning system which distributes appropriate amount of refrigerant to a plurality of air conditioning units

A multiple air conditioning system comprising:

• a plurality of air conditioning units for respectively supplying conditioned air to spaces, each air conditioning unit having a required air conditioning capacity when operating;
• a variable refrigerant supply unit for supplying refrigerant to the plurality of air conditioning units, the refrigerant supply unit including a variable capacity compressor and an inverter which controls the capacity of the compressor by changing an output frequency thereof on the basis of the sum total of the required air conditioning capacity of each air conditioning unit;
• refrigerant flow sensor means for respectively detecting an actual amount (Ra) of refrigerant flowing through each air conditioning unit;
• refrigerant flow control means for respectively controlling the amount of refrigerant flowing through each air conditioning unit, the refrigerant flow control means including a plurality of variable opening valves corresponding to the plurality of air conditioning units, each variable opening valve having an actual opening degree (Oa) when operating;
• means for setting a desired temperature in the space;
• means for detecting an actual temperature in the space;
• a plurality of air conditioning unit controllers corresponding to the plurality of air conditioning units for respectively controlling the operation of the plurality of air conditioning units, each air conditioning unit controller including,
• means for calculating the difference between the
• actual temperature and the desired temperature as a required air conditioning capacity,
• means for determining a target amount (Rs) of refrigerant flowing into the air conditioning unit based on the required air conditioning capacity,
• means for determining a target opening degree (Os) of the variable opening valve on the basis of the required air conditioning capacity,
• means for comparing the actual amount (Ra) of refrigerant with the target amount (Rs),
• means for comparing the actual opening degree (Oa) of the variable opening valve with the target opening degree (Os),
• means for outputting a "sufficient" signal when the actual amount (Ra) of refrigerant is not less than the target amount (Rs) and the actual opening degree (Oa) of the variable opening valve is not less than the target opening degree (Os),
• means for outputting an "excess" signal when the actual amount (Ra) of refrigerant is not less than the target amount (Rs) and the target opening degree (Os) of the variable opening valve is greater than the actual opening degree (Oa), and
• means for outputting an "insufficient" signal when the target amount (Rs) of refrigerant is greater than the actual amount (Ra) and the actual opening degree (Oa) of the variable opening valve is not less than the target opening degree (Os);
• and
• refrigerant supply unit controller for controlling the operation of the refrigerant supply unit, the refrigerant supply unit controller including,
• means for maaintaining the present output frequency of the inverter when only the "sufficient" signal or both the "sufficient" and "excess" signals are output from the plurality of the air conditioning unit controllers,
• means for decreasing the output frequency of the inverter when only the "excess" signal is output from the plurality of the air conditioning unit controllers, and
• means for increasing the output frequency of the inverter when only the "insufficient" signal is output from the plurality of air conditioning unit controllers.