Refrigeration system and method utilizing combined economizer and engine coolant heat exchanger

A transport refrigeration system for heating and cooling a conditioned space, comprising:

• a refrigerant compressor having a suction port, a discharge port, and an intermediate pressure port, said compressor being driven by an internal combustion engine having a liquid coolant system;
• a refrigeration circuit including a heating coil and an evaporator assembly thermally connected to a conditioned space, and a condenser;
• mode valve means for selectively routing refrigerant from said compressor discharge port in either a heating path to said heating coil or a cooling path to said evaporator assembly via said condenser, and
• a heat exchanger means connected to said intermediate pressure port of said compressor for transferring heat from said engine coolant system to refrigerant entering said intermediate pressure port when said mode valve means routes refrigerant along said heating path, said heat exchanger means including a thermal buffer means formed from a volume of liquid refrigerant for moderating the transfer of heat to said refrigerant from coolant in said coolant system, and a refrigerant expansion means, and also functions to subcool refrigerant flowing to said evaporator means when said mode valve means routes refrigerant along said cooling path.

A transport refrigeration system for heating and cooling a conditioned space, comprising:

• a screw-type refrigerant compressor having a suction port, a discharge port, and an intermediate pressure port, said compressor being driven by an internal combustion engine having a liquid coolant system;
• a refrigeration circuit including a heating coil and an evaporator assembly thermally connected to a conditioned space, a condenser downstream of the evaporator assembly, and a condenser valve for admitting refrigerant into the condenser;
• three-way mode valve means for selectively routing refrigerant from said compressor discharge port in either a heating path to said heating coil or a cooling path to said condenser valve and said evaporator assembly, and
• a heat exchanger means having an inlet for receiving refrigerant in said circuit and an outlet for discharging said refrigerant into said intermediate pressure port of said compressor for transferring heat from said engine coolant system to refrigerant entering said intermediate pressure port when said mode valve means routes refrigerant along said heating path, and for subcooling refrigerant enroute to said evaporator assembly when said mode valve means routes said refrigerant along said cooling path, wherein said heat exchanger means includes a thermal buffer means formed from a volume of refrigerant from said circuit for moderating the transfer of heat from engine coolant to refrigerant flowing between said inlet and outlet.

A transport refrigeration system for heating and cooling a conditioned space, comprising:

• a refrigerant compressor having a suction port and a discharge port and being driven by an internal combustion engine having a fluid coolant system;
• a refrigeration circuit including a heating coil and an evaporator assembly thermally connected to a conditioned space and a condenser upstream of said evaporator assembly, and a condenser valve for admitting refrigerant into the condenser;
• mode valve means for selectively routing refrigerant from said compressor discharge port in either a heating path to said heating coil or a cooling path to said evaporator assembly via said condenser valve, and
• a heat exchanger means upstream of said suction port of said compressor for transferring heat from coolant from said engine coolant system to refrigerant entering said suction port when said mode valve means routes refrigerant along said heating path, including a thermal buffer means for moderating the transfer of heat to said refrigerant from said coolant.