Refrigeration system with separate feedstreams to multiple evaporator zones

A refrigeration system comprising:

• (a) a fluid tight circulation loop comprising a continuous length of tubing, the fluid tight circulation loop including a compressor, a condenser and an evaporator, the circulating loop being configured to continuously circulate a refrigerant which is capable of existing in a liquefied state, a gaseous state and a two-phase state comprising both refrigerant in the liquefied state and refrigerant in the gaseous state, the evaporator having an outlet port and at least three evaporator zones in series provided by the continuous length of tubing, each evaporator zone having (i) an inlet port and (ii) an evaporator feed input control valve upstream of the inlet port, the circulation loop being further configured to (i) compress refrigerant in a gaseous state within the compressor and cool the refrigerant within the condenser to yield refrigerant in the liquefied state;
• (ii) flow refrigerant from the condenser into the evaporator via the inlet port and the control valve of each evaporator zone, wherein the refrigerant partially exists in a two-phase state, and wherein refrigerant introduced into each evaporator zone through its inlet port and evaporator feed input control valve flows directly into the next evaporator zone in series until the refrigerant exits the evaporator through the outlet port;
• and (iii) flow refrigerant from the evaporator to the compressor;
• and
• (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon a measured condition of the refrigerant received from a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port.

A method of controlling a refrigeration system, wherein the refrigeration system comprises a refrigerant disposed within a fluid-tight circulation loop comprising a continuous length of tubing, the refrigeration system including a compressor, a condenser and an evaporator, the refrigerant being capable of existing in a liquefied state, a gaseous state and a two-phase state comprising both refrigerant in the liquefied state and refrigerant in the gaseous state, the evaporator having an outlet port and at least three evaporator zones in series provided by the continuous length of tubing, each evaporator zone having an (i) evaporator zone inlet port and (ii) an evaporator feed input control valve upstream of the inlet port, the method comprising the steps of:

• (a) compressing refrigerant in a gaseous state within the compressor and cooling the refrigerant within the condenser to yield refrigerant in the liquefied state;
• (b) flowing refrigerant from the condenser into the evaporator via the inlet port and the control valve of each evaporator zone, wherein the refrigerant partially exists in a two-phase state, and wherein refrigerant introduced into each evaporator zone through its inlet port and evaporator feed input control valve flows directly into the next evaporator zone in series until the refrigerant exits the evaporator through the outlet port in step (c);
• (c) flowing refrigerant from the evaporator to the compressor;
• d) measuring the condition of the refrigerant with a refrigerant condition sensor disposed within each of the evaporator zones;
• and
• e) controlling with a controller the flow rate of refrigerant to the evaporator in step (b) based upon the measured condition of the refrigerant condition of the refrigerant from step (d), wherein the controlling of the refrigerant flow rate to the evaporator is carried out by controlling the refrigerant flow rate to each of the evaporator zones with separate signals from the controller.