Refrigeration system having heat pump and multiple modes of operation

A refrigeration system having both a heating mode for providing heat to a load space and a cooling mode for removing heat from the load space, the refrigeration system comprising:

• a first refrigerant circuit extending between a compressor, an evaporator, an expansion device, and a first heat exchanger, the first refrigerant circuit defining a flow path for a refrigerant traveling in a direction along the refrigerant circuit during operation of the refrigeration system in the heating mode and the cooling mode;
• a second refrigerant circuit extending between the condenser and a second heat exchanger, the second refrigerant circuit including a first refrigerant pump;
• and
• a third refrigerant circuit extending between the evaporator and the second heat exchanger, the third refrigerant circuit including a second refrigerant pump, the second refrigerant pump being operational during operation in the heating mode and being idle during operation in the cooling mode.

A method of operating a refrigeration system, the method comprising the acts of:

• directing a refrigerant along a refrigerant circuit in a direction between a compressor, an evaporator, an expansion device, and a first heat exchanger during operation of the refrigeration system in a cooling mode;
• operating a first pump when the refrigeration system is operating in the cooling mode to circulate refrigerant through a second heat exchanger;
• transferring heat from a load space to the refrigerant in the refrigerant circuit when the refrigeration system is operating in the cooling mode;
• stopping the first pump when the refrigeration system is operating in a heating mode;
• directing the refrigerant along the refrigerant circuit in the direction during operation of the refrigeration system in the heating mode;
• operating a second pump when the refrigeration system is operating in the heating mode to circulate refrigerant through the second heat exchanger in heat exchange relation with the refrigerant of the refrigerant circuit;
• and
• transferring heat to the load space from the refrigerant in the refrigerant circuit when the refrigeration system is operating in the heating mode.