Air-conditioning apparatus

Abstract

An air-conditioning apparatus includes refrigerant systems that each include an outdoor unit and indoor units and that air-condition a single room, and circulators for making a temperature distribution in the room uniform. The air-conditioning apparatus determines a load on each of the two refrigerant systems in operation, and, if it is determined that improvement of operating efficiency is possible on the basis of the determination result, performs a system-selective operation in which operation of one of the refrigerant systems determined to be under a low load is stopped and the other refrigerant system determined to be under a high load is selectively performed, and causes the circulators to transport blown air blown from the indoor units of the refrigerant system determined to be under a high load to an air-conditioned zone of the refrigerant system determined to be under a low load.

1 . An air-conditioning apparatus comprising:
 three refrigerant systems each including an outdoor unit, and one or more indoor units and configured to air-condition a single room;   one or more circulators configured to make a temperature distribution in the room uniform;   a load determination device configured to determine a load on each of the three refrigerant systems in operation; and   a controller configured to control operations of the three refrigerant systems and the circulators, wherein   if the controller determines that improvement of operating efficiency is expected on a basis of a determination result obtained by the load determination device, the controller performs a system-selective operation in which one of the refrigerant systems determined to be under a low load is stopped and the other refrigerant systems determined to be under a high load or an intermediate load that the load thereof is higher than the determined low load is selectively performed, operates one of the circulators so as to transport air from one of the refrigerant systems determined to be under the high load or the intermediate load toward an air-conditioned zone of the refrigerant system determined to be under the low load.   
     
     
         2 . The air-conditioning apparatus of  claim 1  wherein,
 if the controller determines that improvement of operating efficiency is expected on the basis of the determination result obtained by the load determination device, the controller operates one of the circulators disposed at a position at which the circulator is capable of drawing blown air blown from one of the refrigerant systems determined to be under the high load or the intermediate load, and causes the circulator to draw the blown air and to blow the air toward an air-conditioned zone of the refrigerant system determined to be under the low load. 
 
     
     
         3 . The air-conditioning apparatus of  claim 1 , wherein
 each of the three refrigerant systems is disposed so as to air-condition corresponding three air-conditioned zones formed by dividing the room into three in one direction, and   if the refrigerant system determined to be under the low load is one of two refrigerant systems that air-condition the air-conditioned zones at both ends, the controller determines whether improvement of operating efficiency is expected by selectively operating one of the refrigerant systems that air-conditions one of the air-conditioned zones at a center on the basis of the determination result obtained by the load determination device, and if the controller determines that improvement of operating efficiency is expected, the controller performs the system-selective operation in which the refrigerant system determined to be under the low load is stopped and the operation of the refrigerant system that air-conditions the air-conditioned zone at the center is selectively performed.   
     
     
         4 . The air-conditioning apparatus of  claim 3 , wherein the controller determines that improvement of operating efficiency is expected if a sum of a product of an operating frequency and a stroke volume of a compressor of the refrigerant system determined to be under the low load and a product of an operating frequency and a stroke volume of a compressor of the refrigerant system that air-conditions the air-conditioned zone at the center is smaller than or equal to a product of a compressor frequency and a stroke volume of the compressor of the refrigerant system that air-conditions the air-conditioned zone at the center, the compressor frequency being a frequency at which overall adiabatic efficiency of the compressor is maximum. 
     
     
         5 . The air-conditioning apparatus of  claim 1 , wherein
 each of the three refrigerant systems is disposed so as to air-condition corresponding three air-conditioned zones formed by dividing the room into three in one direction, and   if the refrigerant system determined to be under the low load is one of the refrigerant systems that air-conditions one of the air-conditioned zones at a center, the controller determines whether improvement of operating efficiency is expected by selectively operating one of the refrigerant systems determined to be under the high load, and if the controller determines that improvement of operating efficiency is expected, the controller performs the system-selective operation in which the refrigerant system determined to be under the low load is stopped and the operation of the refrigerant system determined to be under the high load is selectively performed.   
     
     
         6 . The air-conditioning apparatus of  claim 5 , wherein if the controller determines that improvement of operating efficiency is not expected by selectively operating one of the refrigerant systems determined to be under the high load, the controller determines whether improvement of operating efficiency is expected by selectively operating one of the refrigerant systems determined to be under the intermediate load, and if the controller determines that improvement of operating efficiency is expected, the controller performs the system-selective operation in which the refrigerant system determined to be under the low load is stopped and the operation of the refrigerant system determined to be under the intermediate load is selectively performed. 
     
     
         7 . The air-conditioning apparatus of  claim 6 , wherein the controller determines that improvement of operating efficiency is expected by selectively operating the refrigerant system determined to be under the high load if a first condition is satisfied, the first condition being a condition that a sum of a product of an operating frequency and a stroke volume of a compressor of the refrigerant system determined to be under the low load and a product of an operating frequency and a stroke volume of a compressor of the refrigerant system determined to be under the high load is smaller than or equal to a product of a compressor frequency and a stroke volume of the compressor of the refrigerant system determined to be under the high load, the compressor frequency being a frequency at which overall adiabatic efficiency of the compressor is maximum. 
     
     
         8 . The air-conditioning apparatus of  claim 7 , wherein, if the first condition is not satisfied, the controller determines whether a second condition is satisfied, the second condition being a condition that a sum of a product of an operating frequency and a stroke volume of a compressor of the refrigerant system determined to be under the low load and a product of an operating frequency and a stroke volume of a compressor of the refrigerant system determined to be under the intermediate load is smaller than or equal to a product of a compressor frequency and a stroke volume of the compressor of the refrigerant system determined to be under the intermediate load, the compressor frequency being a frequency at which overall adiabatic efficiency of the compressor is maximum, and if the second condition is satisfied, the controller determines that improvement of operating efficiency is expected by selectively operating the refrigerant system under the intermediate load.