Thermal energy storage and cooling system with secondary refrigerant isolation
Disclosed are a method and device for a refrigerant-based thermal storage system wherein a condensing unit and an ice-tank heat exchanger can be isolated through a second heat exchanger. The disclosed embodiments provide a refrigerant-based ice storage system with increased reliability, lower cost components, and reduced power consumption compared to a single phase system such as a glycol system.
1. A refrigerant-based thermal energy storage and cooling system comprising:
a first refrigerant loop containing a first refrigerant comprising:
a condensing unit, said condensing unit comprising a compressor and a first condenser;
an expansion device connected downstream of said condensing unit; and,
a first evaporator on a primary side of an isolating heat exchanger located downstream of said expansion device;
a second refrigerant loop containing a second refrigerant comprising:
a second condenser on a secondary side of said isolating heat exchanger;
a tank filled with a fluid capable of a phase change between liquid and solid and containing a primary heat exchanger therein, said primary heat exchanger in fluid communication with said second condenser and that uses said second refrigerant from said second condenser to cool said fluid and to freeze at least a portion of said fluid within said tank;
a refrigerant management vessel connected to receive said second refrigerant from said isolating heat exchanger in a first time period, and to receive said second refrigerant from said primary heat exchanger in a second time period;
a load heat exchanger connected to said refrigerant management vessel that transfers cooling capacity of said second refrigerant to a heat load during said second time period; and,
a liquid refrigerant pump for distributing said second refrigerant from said refrigerant management vessel to said primary heat exchanger in said first time period and from said refrigerant management vessel to said load heat exchanger in said second time period.
2. The system of claim 1 wherein said expansion device is a thermal expansion valve.
3. The system of claim 1 wherein said first refrigerant loop further comprises:
a refrigerant receiver for accumulation and storage of said first refrigerant.
4. The system of claim 3 wherein said expansion device is a mixed-phase regulator.
5. The system of claim 1 wherein said fluid is a eutectic material.
6. The system of claim 1 wherein said fluid is water.
7. The system of claim 1 wherein said first refrigerant is a different material from said second refrigerant.
8. The system of claim 1 further comprising:
an air handler unit that assists in distributing cooling from said load heat exchanger to said heat load; and,
a photovoltaic power source for powering said liquid refrigeration pump and said air handler.
9. The system of claim 1 wherein said second refrigerant loop further comprises:
a valve structure for isolating said second refrigeration loop within said isolating heat exchanger, said primary heat exchanger, said refrigerant management vessel, and said liquid refrigerant pump to form an ice-make circuit.
10. The system of claim 1 wherein said second refrigerant loop further comprises:
a valve structure for isolating said second refrigeration loop within said primary heat exchanger, said refrigerant management vessel, said liquid refrigerant pump, and said load heat exchanger to form an ice-melt circuit.
11. The system of claim 1 wherein said second refrigerant loop further comprises:
a valve structure for isolating said second refrigeration loop within said isolating heat exchanger, said refrigerant management vessel, said liquid refrigerant pump, and said load heat exchanger to form a direct cooling circuit.
12. The system of claim 1 further comprising:
a third refrigerant loop that allows said first refrigerant to bypass said primary side of said isolating heat exchanger and flow through said load heat exchanger during a third time period.
13. The system of claim 12 wherein said third refrigerant loop further comprises:
a refrigerant receiver for accumulation and storage of said first refrigerant.
14. The system of claim 13 wherein said expansion device is a mixed-phase regulator.
15. The system of claim 1 wherein said refrigerant management vessel is connected between said secondary side of said isolating heat exchanger and said primary heat exchanger.
16. The system of claim 1 wherein said load heat exchanger is at least one mini-split evaporator.