Refrigeration system controlled by refrigerant quality within evaporator

A refrigeration system comprising:

• (a) a 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 liquified state, a gaseous state and a two-phase state comprising both refrigerant in the liquified state and refrigerant in the gaseous state, the evaporator having one or more evaporator tubes, an upstream section with an inlet opening and a downstream section with an outlet opening, the circulation loop being further configured to (i) compress refrigerant in a gaseous state within the compressor and cool the refrigerant in the condenser to yield refrigerant in a liquified state;
• (ii) flow the refrigerant in a liquified state into the evaporator;
• (iii) reduce the pressure of the refrigerant within the evaporator to yield refrigerant in a two-phase state;
• (iv) reduce the pressure of the refrigerant in a two-phase state within the evaporator to yield a refrigerant in a gaseous state;
• (v) flow refrigerant in a gaseous state from the evaporator to the compressor;
• and (vi) repeat steps (i)-(v);
• (b) a refrigerant condition sensor disposed within the evaporator upstream of the outlet opening and downstream of the inlet opening to sense the ratio of the measured volume of vapor to the volume of liquid in refrigerant in a two-phase state within the evaporator;
• and
• (c) a controller for controlling the flow of refrigerant in a liquid state to the evaporator based upon the ratio of the measured volume of vapor to the volume of liquid in refrigerant in a two-phase state, so that the flow rate of refrigerant to the evaporator can be controlled to a flow rate required to wet at least most of the entire surface of the evaporator tubes.

A method of controlling a refrigeration system, wherein the refrigeration system comprises a refrigerant disposed within a fluid-tight circulation loop including a compressor, a condenser and an evaporator comprising one or more evaporator tubes, 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 upstream section with an inlet opening and a downstream section with an outlet opening, 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, wherein the refrigerant partially exists in a two-phase state;
• (c) flowing refrigerant from the evaporator to the compressor;
• (d) repeating steps (a)-(c);
• (e) measuring the ratio of the measured volume of vapor to the volume of liquid in refrigerant in a two-phase state with a refrigerant condition sensor disposed within the evaporator upstream of the outlet opening and downstream of the inlet opening;
• and
• (f) controlling the flow rate of refrigerant to the evaporator in step (b) based upon the measured ratio from step (e) to a flow rate required to wet at least most of the entire surface of the evaporator tubes;
• wherein refrigerant in a liquified state from step (a) is precooled prior to being flowed into the evaporator in step (b);
• and
• wherein a plurality of the upstream circuits are connected to a plurality of the downstream circuits by a midsection header.

A method for cooling a refrigerant comprising the steps of:

• (a) compressing refrigerant in a gaseous state within a compressor and cooling the refrigerant within a condenser to yield refrigerant in a liquefied state;
• (b) flowing refrigerant from the condenser into an evaporator comprising one or more evaporator tubes;
• (c) flowing refrigerant from the evaporator to the compressor;
• (d) repeating steps (a)-(c);
• (e) measuring the ratio of the measured volume of vapor to the volume of liquid in refrigerant in a two-phase state with a refrigerant condition sensor disposed within the evaporator upstream of the outlet opening;
• and
• (f) controlling the flow rate of refrigerant to the evaporator in step (b) based upon the measured ratio from step (e) to a flow rate required to wet at least most of the entire surface of the evaporator tubes.