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

Patent metadata

Field	Value
Publication number	US-9874384-B2
Application number	US-201614995119-A
Country	US
Kind code	B2
Filing date	Jan 13, 2016
Priority date	Jan 13, 2016
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

The refrigeration system includes a compressor, a condenser, an evaporator, one or both of a receiver drier unit and an accumulator unit fluidly connected by refrigerant lines to form a refrigerant circuit. The receiver drier unit includes a receiver drier and a first sensor, and the accumulator unit includes an accumulator and a second sensor. A controller is electrically connected to the first and second sensors and in some cases electrically connected to an electrical valve. The electrical valve is fluidly connected to a refrigerant reservoir. The controller determines the refrigerant charge level, and selectively controls the electrical valve to allow the refrigerant to flow from the refrigerant reservoir to the refrigerant circuit when the refrigerant charge level is below the predetermined refrigerant charge level.

First claim

What is claimed is:

1. A refrigeration system, comprising:
a compressor to compress a refrigerant;
a condenser disposed downstream of the compressor to condense the refrigerant;
an evaporator disposed downstream of the condenser to vaporize the refrigerant;
refrigerant lines fluidly connecting the compressor, the condenser and the evaporator in series to form a refrigerant circuit for circulating the refrigerant;
an assembly disposed in the refrigerant circuit and comprising one or more of the following:
a receiver drier unit disposed between the condenser and the evaporator; and
an accumulator unit disposed between the evaporator and the compressor;
wherein the receiver drier unit comprises:
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;

wherein the accumulator unit comprises:
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; and

a controller electrically connected to the assembly and configured to perform one or more of the following:
determine a sub-cooling level based on the temperature and pressure measured by the first sensor;
determine a super-heating level based on the temperature and pressure measured by the second sensor; and
determine a refrigerant charge level based at least in part on the determined sub-cooling level or the determined super-heating level.

2. The refrigeration system of claim 1 , wherein the assembly further comprises an electronic valve fluidly connected to a refrigerant reservoir, wherein:
the electronic valve is installed at the receiver drier or at the accumulator; and
the electronic valve is selectively operated to allow flow of the refrigerant from the refrigerant reservoir to the refrigerant circuit, wherein the flow is driven by pressure difference between the refrigerant reservoir and the receiver drier or between the refrigerant reservoir and the accumulator, thereby maintaining the refrigerant charge level above a predetermined refrigerant charge level.

3. The refrigeration system of claim 1 , further comprising:
an electronic valve fluidly connected to the refrigerant circuit and a refrigerant reservoir, wherein the controller controls the electronic valve to be selectively opened or closed in accordance with the determined refrigerant charge level, thereby allowing flow of the refrigerant from the refrigerant reservoir to the refrigerant circuit when the determined refrigerant charge level is below a predetermined refrigerant charge level.

4. The refrigeration system of claim 3 , wherein the electronic valve is integrated into the receiver drier unit or the accumulator unit.

5. The refrigeration system of claim 3 , wherein the electronic valve is coupled to the refrigerant circuit at a location other than the receiver drier unit or the accumulator unit.

6. The refrigeration system of claim 1 , wherein the first sensor is a temperature and pressure transducer installed at any one of an inlet, an outlet and an inside of the receiver drier.

7. The refrigeration system of claim 1 , wherein the first sensor includes a first temperature sensor and a first pressure sensor.

8. The refrigeration system of claim 1 , wherein the second sensor is a temperature and pressure transducer installed at any one of an inlet, an outlet and an inside of the accumulator.

9. The refrigeration system of claim 1 , wherein the second sensor includes a second temperature sensor and a second pressure sensor.

10. The refrigeration system of claim 1 , wherein the controller is mounted at the receiver drier or the accumulator.

11. The refrigeration system of claim 1 , wherein the sub-cooling level is determined using a look-up table in accordance with the temperature and pressure measured by the first sensor.

12. The refrigeration system of claim 11 , wherein the look-up table is stored in a memory associated with the controller.

13. The refrigeration system of claim 1 , wherein the super-heating level is determined using a look-up table in accordance with the temperature and pressure measured by the second sensor.

14. The refrigeration system of claim 13 , wherein the look-up table is stored in a memory associated the controller.

15. The refrigeration system of claim 1 , wherein the controller predicts whether and when a failure, in which the refrigerant charge level is below a predetermined refrigerant level, is likely to occur by extrapolating the determined refrigerant charge levels over time.

16. The refrigeration system of claim 1 , wherein the controller predicts whether and when a failure, in which the refrigerant charge level is below a predetermined refrigerant level, is likely to occur based on one or more of the following: a trend of the determined refrigerant charge levels over time, exterior temperature, interior temperature and humidity.

17. The refrigeration system of claim 1 , wherein the controller predicts how long the refrigerant will last based on one or more of the determined sub-cooling levels over time and the determined super-heating levels over time.

18. The refrigeration system of claim 1 , wherein the controller performs one or more of the following:
calculating a compression ratio of the compressor;
determining whether a blockage occurs in the refrigerant circuit based on the calculated compression ratio; and
determining a location of the blockage, if a blockage has occurred, based at least in part on the determined sub-cooling level and the determined super-heating level.

19. The refrigeration system of claim 1 , wherein the controller determines whether a blockage occurs in the refrigerant circuit based at least in part on the determined sub-cooling level or the determined super-heating level, and determines a location of the blockage if it is determined that a blockage has occurred.

20. The refrigeration system of claim 19 , wherein the controller outputs a signal to request maintenance if it is determined that a blockage has occurred.

21. The refrigeration system of claim 1 , wherein the controller is electrically connected to the compressor, counts clutch cycles of the compressor and predicts clutch life of the compressor based on one or more of the following: the clutch cycles, clutch temperature and current.

22. The refrigeration system of claim 1 , wherein the controller is electrically or wirelessly coupled to an electronic device and outputs one or more of the sub-cooling level, the super-heating level and the refrigerant charge level.

23. The refrigeration system of claim 22 , wherein the electronic device is a display, a receiver, a smartphone or a computer.

24. The refrigeration system of claim 22 , wherein the electronic device is located remotely from the refrigeration system.

25. The refrigeration system of claim 1 , wherein the controller is electrically or wirelessly coupled to an electronic device and outputs a warning signal if one or more of the following occur: the determined sub-cooling level is outside of a predetermined sub-cooling range, the determined super-heating level is outside of a predet

Assignees

• Bergstrom Inc

Inventors

• Connell Brett S
• Sullivan Aaron D
• Herrmann Brett J
• Zeigler Terry

Classifications

• F25B2700/195

  of the condenser · CPC title

• F25B49/02

  for compression type machines, plants or systems · CPC title

• F25B2345/006

  characterised by charging or discharging valves · CPC title

• F25B2339/0441

  containing a drier or a filter · CPC title

• F25B2700/2111

  of a heat storage receiver · CPC title