Heat source unit for refrigeration apparatus including a heat-source-side heat exchanger having a heat exchange region of variable size

A heat source unit forming, together with a utilization-side unit, a refrigeration apparatus including a refrigerant circuit performing a refrigeration cycle, the heat source unit housing at least a compressor and a heat-source-side heat exchanger, each of which is provided for the refrigerant circuit, wherein

• the heat source unit is configured to perform a cooling action in which the heat-source-side heat exchanger functions as a condenser to cool a target in the utilization-side unit and a heating action in which the heat-source-side heat exchanger functions as an evaporator to heat a target in the utilization-side unit,
• the heat-source-side heat exchanger is connected to a heat source water circuit in which heat source water circulates so that a refrigerant circulating in the refrigerant circuit exchanges heat with the heat source water, the heat-source-side heat exchanger having a heat exchange region, of a variable size, in which the refrigerant flows and exchanges heat with the heat source water,
• the heat source unit comprises a controller which adjusts the size of the heat exchange region of the heat-source-side heat exchanger based on a differential temperature index value indicating a difference between a temperature of the refrigerant in the utilization-side unit and a temperature of the heat source water in the heat source water circuit,
• the heat-source-side heat exchanger includes a first heat exchange section and a second heat exchange section respectively including refrigerant channels connected to the refrigerant circuit and heat source water channels connected to the heat source water circuit,
• the first heat exchange section is configured to exchange heat between the refrigerant flowing through the refrigerant channel and the heat source water flowing through the heat source water channel, and the second heat exchange section is configured to exchange heat between the refrigerant flowing through the refrigerant channel and the heat source water flowing through the heat source water channel,
• the refrigerant channel of the first heat exchange section and the refrigerant channel of the second heat exchange section are connected to each other in parallel,
• the heat source water channel of the first heat exchange section and the heat source water channel of the second heat exchange section are connected to each other in parallel,
• the heat-source-side heat exchanger includes
• a liquid valve connected to one end of the refrigerant channel of the second heat exchange section,
• a gas valve connected to the other end of the refrigerant channel of the second heat exchange section, and
• a water valve connected to one end of the heat source water channel of the second heat exchange section, and
• the controller is configured to
• open the liquid valve, the gas valve, and the water valve to cause the refrigerant and the heat source water to flow through both of the first heat exchange section and the second heat exchange section,
• open the liquid valve and close the gas valve and the water valve to cause the second heat exchange section to rest in the cooling action, and
• open the gas valve and close the liquid valve and the water valve to cause the second heat exchange section to rest in the heating action.