Estimation apparatus of heat transfer medium flow rate, heat source machine, and estimation method of heat transfer medium flow rate

An estimation apparatus of heat transfer medium flow rate for estimating a flow rate of a heat transfer medium in a heat source machine including:

• a centrifugal compressor for sucking and compressing a refrigerant;
• a condenser for condensing the compressed refrigerant using a heat source medium;
• an evaporator for evaporating the condensed refrigerant and carrying out heat exchange between the refrigerant and the heat transfer medium, a bypass pipe arrangement provided between the condenser and the evaporator for flowing the refrigerant from the condenser to the evaporator, and a valve provided to adjust a flow rate of the refrigerant flowing in the bypass pipe arrangement, the estimation apparatus of heat transfer medium flow rate comprising:
• a storing portion for storing an aerodynamic characteristic map indicating a rotating stall line causing a rotating stall and a plurality of machine Mach number lines showing a sonic velocity in the refrigerant sucked in by the compressor on a map displaying a first parameter reflecting a suction volume of the compressor and a second parameter reflecting a head of the compressor;
• a first parameter computation portion for computing the second parameter and deriving the first parameter according to the second parameter from the aerodynamic characteristic map;
• and
• a heat transfer medium flow rate computation portion for computing an amount of heat exchanged between the refrigerant and the heat transfer medium in the evaporator based on the suction volume of the compressor according to the first parameter derived by the first parameter computation portion and a density of the refrigerant sucked into the compressor, and computing a flow rate of the heat transfer medium based on the amount of the heat,
• wherein the storing portion stores a plurality of the aerodynamic characteristic maps that differ according to the degree of opening of the valve, and
• the first parameter computation portion derives the first parameter according to the second parameter from the aerodynamic characteristic map corresponding to the degree of opening of the valve.

An estimation method of heat transfer medium flow rate for estimating a flow rate of a heat transfer medium in a heat source machine including:

• a variable-speed centrifugal compressor for sucking and compressing a refrigerant;
• a condenser for condensing the compressed refrigerant using a heat source medium;
• and an evaporator for evaporating the condensed refrigerant and carrying out heat exchange between the refrigerant and the heat transfer medium, the estimation method of heat transfer medium flow rate comprising:
• a first stage, wherein
• a storing portion preliminarily stores an aerodynamic characteristic map indicating a rotating stall line causing a rotating stall and a plurality of machine Mach number lines showing a sonic velocity in the refrigerant sucked in by the compressor on a map displaying a first parameter reflecting a suction volume of the compressor and a second parameter reflecting a head of the compressor;
• by computing the second parameter, the first parameter according to the second parameter is derived from the aerodynamic characteristic map;
• and
• a second stage, wherein
• the amount of heat exchanged between the refrigerant and the heat transfer medium in the evaporator is computed based on the suction volume of the compressor according to the first parameter derived by the first stage and a density of the refrigerant sucked into the compressor, and
• a flow rate of the heat transfer medium is computed based on the amount of the heat,
• wherein the storing portion stores a plurality of aerodynamic characteristic maps that differ according to the number of revolutions of the compressor, and
• the first parameter according to the second parameter is derived from the aerodynamic characteristic map corresponding to the number of revolutions of the compressor.

An estimation method of heat transfer medium flow rate for estimating a flow rate of a heat transfer medium in a heat source machine including:

• a centrifugal compressor for sucking and compressing a refrigerant;
• a condenser for condensing the compressed refrigerant using a heat source medium;
• an evaporator for evaporating the condensed refrigerant and carrying out heat exchange between the refrigerant and the heat transfer medium, a bypass pipe arrangement provided between the condenser and the evaporator for flowing the refrigerant from the condenser to the evaporator, and a valve provided to adjust a flow rate of the refrigerant flowing in the bypass pipe arrangement, the estimation method of heat transfer medium flow rate comprising:
• a first stage, wherein
• a storing portion preliminarily stores an aerodynamic characteristic map indicating a rotating stall line causing a rotating stall and a plurality of machine Mach number lines showing a sonic velocity in the refrigerant sucked in by the compressor on a map displaying a first parameter reflecting a suction volume of the compressor and a second parameter reflecting a head of the compressor;
• by computing the second parameter, the first parameter according to the second parameter is derived from the aerodynamic characteristic map;
• and
• a second stage, wherein
• the amount of heat exchanged between the refrigerant and the heat transfer medium in the evaporator is computed based on the suction volume of the compressor according to the first parameter derived by the first stage and a density of the refrigerant sucked into the compressor, and
• a flow rate of the heat transfer medium is computed based on the amount of the heat,
• wherein the storing portion stores a plurality of the aerodynamic characteristic maps that differ according to the degree of opening of the valve, and
• the first parameter according to the second parameter is derived from the aerodynamic characteristic map corresponding to the degree of opening of the valve.