Abstract: The invention resides in improvements to refrigeration systems which rely on circulation of refrigerant gas through compression and expansion phases, and thereby discharging heat from a fluid to be cooled. The invention includes a subcooler (38) in the refrigerant loop, downstream of the refrigerant condenser (34) and a gas trap (36) between the condenser (34) and the subcooler (38), that assures temperature drop in the subcooler (38). The invention also comprehends a shut-off valve (44) between the compressor and the heat source heat exchanger (28). The invention further includes a high capacity-to-volume oil to air heat exchanger (48), for cooling the lubricating oil in the oil loop (26). Preferred refrigerant is ammonia. Incorporating the above improvements into refrigeration systems enables an overall reduction in system sizing. Such systems, having heat exchange capacity of at least 200,000 Btu/hr., up to at least 500,000 Btu/hr.

Abstract: The invention resides in improvements to refrigeration systems which rely on circulation of refrigerant gas through compression and expansion phases, and thereby discharging heat from a fluid to be cooled. The refrigeration systems of the invention include a refrigerant loop (24) and a lubricating oil loop (26). The oil loop includes a high capacity-to-volume oil to air oil cooler (48), for cooling the lubricating oil in the oil loop (26). The oil cooler includes a fan, and a variable speed drive for controlling the speed of rotation of the fan. The Preferred refrigerant is ammonia. Incorporating the above improvements into refrigeration systems enables an overall reduction in system sizing, and constancy in the temperature of the oil at the exit of the oil cooler. Such systems, having heat exchange capacity of at least 200,000 Btu/hr., up to at least 500,000 Btu/hr.

Abstract: The invention resides in improvements to refrigeration systems which rely on circulation of refrigerant gas through compression and expansion phases, and thereby discharging heat from a fluid to be cooled. The invention includes a subcooler (38) in the refrigerant loop, downstream of the refrigerant condenser (34) and a gas trap (36) between the condenser (34) and the subcooler (38), that assures temperature drop in the subcooler (38). The invention also comprehends a shut-off valve (44) between the compressor and the heat source heat exchanger (28). The invention further includes a high capacity-to-volume oil to air heat exchanger (48), for cooling the lubricating oil in the oil loop (26). Preferred refrigerant is ammonia. Incorporating the above improvements into refrigeration systems enables an overall reduction in system sizing. Such systems, having heat exchange capacity of at least 200,000 Btu/hr., up to at least 500,000 Btu/hr.