Refrigerant system performance enhancement by subcooling at intermediate temperatures

摘要

A refrigerant system operates in an environment defined by three distinct temperature levels, such as, for instance, the outdoor ambient temperature level, the indoor temperature level and the refrigeration temperature level. The refrigerant system is provided with an air-to-refrigerant heat exchanger located within the general indoor environment and connected to receive the flow of refrigerant from a heat rejection heat exchanger. The air-to-refrigerant heat exchanger gives off heat to the indoor air and in the process further cools the refrigerant flowing to an expansion device to thereby increase the cooling effect provided by an evaporator to the refrigeration area. Provisions are also made to partially or entirely bypass the air-to-refrigerant heat exchanger and/or the heat rejection heat exchanger, on a selective basis.

主权项

1. A method of increasing capacity of a refrigerant system including, in serial refrigerant flow relationship, a compressor, a heat rejection heat exchanger with an associated air moving device, an expansion device and an evaporator wherein said heat rejection heat exchanger is exposed to a first environment with a first temperature level there within and said evaporator is exposed to a second environment with a second temperature level there within, with said second temperature level being lower than said first temperature level, and wherein there is a third environment with a third temperature level which is, at least at times, intermediate said first temperature level and said second temperature level, comprising:
positioning an additional air-to-refrigerant heat exchanger to be exposed to said third environment and fluidly interconnecting said air-to-refrigerant heat exchanger between said heat rejection heat exchanger and said expansion device, with respect to refrigerant flow, such that additional cooling can be selectively provided to the refrigerant flowing though said air-to-refrigerant heat exchanger during the time periods when the temperature of the air within the third environment is lower than the temperature of the air within the first environment; wherein the refrigerant system includes a bypass circuit around said air-to-refrigerant heat exchanger and a control, and the method includes selectively bypassing at least a portion of refrigerant around at least a portion of said air-to-refrigerant heat exchanger when the temperature in the first environment is equal to or less than the temperature in the third environment.