Refrigeration system with superheating, sub-cooling and refrigerant charge level control

A refrigeration system, comprising:

• a compressor to compress a refrigerant;
• a condenser disposed downstream of the compressor to condense the refrigerant;
• a receiver drier unit disposed downstream of the condenser, the receiver drier unit comprising:
• a receiver drier configured to perform one or more of the following:
• temporarily store the refrigerant, and absorb moisture from the refrigerant;
• and
• a first sensor installed at the receiver drier to measure temperature and pressure of the refrigerant after it has passed through the condenser;
• an evaporator disposed downstream of the receiver drier unit to vaporize the refrigerant;
• an accumulator unit disposed downstream of the evaporator, the accumulator unit comprising:
• an accumulator configured to restrict liquid refrigerant from entering the compressor;
• and
• a second sensor installed at the accumulator to measure temperature and pressure of the refrigerant after it has passed through the evaporator;
• refrigerant lines fluidly connecting the compressor, the condenser, the receiver drier unit, the evaporator and the accumulator unit in series to form a refrigerant circuit to circulate the refrigerant;
• and
• a controller electrically connected to the first and second sensors and configured to determine one or more of the following:
• a sub-cooling level based on the temperature and pressure measured by the first sensor;
• a super-heating level based on the temperature and pressure measured by the second sensor;
• and
• a refrigerant charge level based at least in part on the determined sub-cooling level or the determined super-heating level.

A method for controlling a refrigeration system, wherein the refrigeration system comprises a first sensor for measuring temperature and pressure of a refrigerant after it has passed through a condenser, a second sensor for measuring temperature and pressure of the refrigerant after it has passed through an evaporator, and an electronic valve fluidly connected to a refrigerant circuit of the refrigeration system and a refrigerant reservoir, the method comprising:

• (a) obtaining a refrigerant sub-cooling level based on the temperature and pressure of the refrigerant measured by the first sensor, and a refrigerant super-heating level based on the temperature and pressure of the refrigerant measured by the second sensor;
• (b) calculating a refrigerant charge level based at least in part on the refrigerant sub-cooling level and the refrigerant super-heating level;
• (c) determining whether the refrigerant charge level is below a predetermined refrigerant charge level;
• and
• (d) selectively controlling the electronic valve, if it is determined that the refrigerant charge level is below the predetermined refrigerant charge level, to allow flow of the refrigerant from the refrigerant reservoir to the refrigerant circuit of the refrigeration system, thereby raising the refrigerant charge level to above the predetermined refrigerant charge level.

A method for controlling a refrigeration system, wherein the refrigeration system comprises a condenser disposed downstream of the compressor, an evaporator disposed downstream of the condenser, and refrigerant lines fluidly connecting the compressor, the condenser and the evaporator in series to form a refrigerant circuit to circulate the refrigerant, the method comprising:

• (a) installing a receiver drier unit in the refrigerant circuit between the condenser and the evaporator, wherein the receiver drier unit comprises a receiver drier and a first sensor installed at the receiver drier to measure temperature and pressure of the refrigerant after it has passed through the condenser;
• (b) installing an accumulator unit in the refrigerant circuit between the evaporator and the compressor, wherein the accumulator unit comprises an accumulator and a second sensor installed at the accumulator to measure temperature and pressure of the refrigerant after it has passed through the evaporator;
• (c) obtaining a refrigerant sub-cooling level based on the temperature and pressure of the refrigerant measured by the first sensor, and a refrigerant super-heating level based on the temperature and pressure of the refrigerant measured by the second sensor;
• (d) calculating a refrigerant charge level based at least in part on the refrigerant sub-cooling level and the refrigerant super-heating level;
• and
• (e) determining one or more of the following:
• whether the refrigerant sub-cooling level is within a predetermined refrigerant sub-cooling range;
• whether the refrigerant super-heating level is within a predetermined refrigerant super-heating range;
• and
• whether the refrigerant charge level is below a predetermined refrigerant charge level.

A method for controlling a refrigeration system, wherein the refrigeration system comprises a condenser disposed downstream of the compressor, a receiver drier disposed downstream of the condenser, an evaporator disposed downstream of the receiver drier, an accumulator disposed downstream of the evaporator, and refrigerant lines fluidly connecting the compressor, the condenser, the receiver drier, the evaporator and the accumulator in series to form a refrigerant circuit to circulate the refrigerant, the method comprising:

• (a) installing a first sensor at the receiver drier to measure temperature and pressure of the refrigerant after it has passed through the condenser;
• (b) installing a second sensor at the accumulator to measure temperature and pressure of the refrigerant after it has passed through the evaporator;
• (c) installing an electronic valve in the refrigerant circuit, wherein the electronic valve is fluidly connected to a refrigerant reservoir;
• (d) obtaining a refrigerant sub-cooling level based on the temperature and pressure of the refrigerant measured by the first sensor, and a refrigerant super-heating level based on the temperature and pressure of the refrigerant measured by the second sensor;
• (e) calculating a refrigerant charge level based at least in part on the refrigerant sub-cooling level and the refrigerant super-heating level;
• (f) determining whether the refrigerant charge level is below a predetermined refrigerant charge level;
• and
• (g) selectively controlling the electronic valve, if it is determined that the refrigerant charge level is below the predetermined refrigerant charge level, to allow flow of the refrigerant from the refrigerant reservoir to the refrigerant circuit of the refrigeration system, thereby raising the refrigerant charge level to above the predetermined refrigerant charge level.