| 摘要 |
PURPOSE:To enable a fast stable operation to be carried out when operating compressor are extentionally added in response to a variation of a freezing load by a method wherein at least one of a plurality of compressors is of a variable volume type, the variable volume type is set to a low capability when the load is more than a full capability of the operating compressor to determine the operating state and then the variable volume type is controlled in its volume. CONSTITUTION:When a load is increased during a single operation of a variable volume type compressor 30A and a discriminating means 46 judges that it is more than the maximum capacity of the compressor 30A, an operating state determining means 47 determines a starting of operation of a positive volume type compressor 30B. Means 43 for determining a degree of opening causes a control valve 36 to be fully opened before starting the operation of the compressor 30B. Result of determination of the volume controlling operation is outputted from an outputting means 45 to the compressor 30B and the control valve 36 just after the stopping of the compressor 30B. The compressor 30A is changed to its minimum capability state and operated. As the operation of the compressor 30B is started, a degree of opening of the control valve 36 is adjusted in such a way as it may be accommodated for the load and then the compressor 30A is operated under its volume controlled state. With such an arrangement, the low pressure capability rapidly reaches the set value and the operation is made stable at an early time. |
