Patent CA-3036846-A1 (CA)
Title: Transcritical co2 rink refrigeration system with transcritical energy recovery ejector
Inventor: SADIGH TEHRANI SHAHIN SS
IPC: F25C3/02
Filed: 2019-03-15
Abstract: A transcritical (note 1) CO2 rink refrigeration system with low and intermediate temperature compressor units, transcritical energy recovery ejector unit and direct CO2 cooled rink pipes (note 2) consisting of: 1. Low pressure receiver that holds low pressure saturated CO2 liquid and gas. separates CO2 liquid and gas and holds normal CO2 liquid surge volume. 2.        CO2 pump unit (note 3) that circulates CO2 liquid from low pressure receiver to rink supply header via liquid recirculating valve. 3. Liquid recirculating valve that stops/starts/regulates liquid CO2 flow to rink supply header. 4. Rink supply header that uniformly distributes CO2 liquid to the rink cooling pipes, 5. Rink cooling pipes that are installed in rink floor, receive CO2 liquid from rink supply header, absorb heat from rink floor, partially evaporate CO2 liquid and convey CO2 liquid and vapor to rink return header. 6. Rink return header that uniformly collects CO2 liquid and gas from rink cooling pipes. 7. Transcritical energy recovery ejector unit that transfers CO2 gas from low pressure receiver to intermediate pressure receiver by generating adequate suction at suction inlet of it as a result of transcritical gas flows from high pressure inlet of it to outlet of it based on Bernoulli's principle. 8. Low temperature compressor unit (compressor and motor) that transfers CO2 gas from low pressure receiver to gas cooler inlet via oil separator (note 4) 9. Intermediate pressure receiver that holds intermediate pressure saturated liquid and gas, separates CO2 liquid and gas and holds normal CO2 liquid surge volume. 10. Liquid make-up valve that stops/starts/regulates liquid CO2 flow from intermediate pressure receiver to low pressure receiver. 11. Intermediate temperature compressor unit (compressor and motor) that transfers CO2 vapor from intermediate pressure receiver to gas cooler inlet via oil separator (note 4). 12. CO2 gas cooler unit that rejects heat from CO2 gas from compressor units discharge temperature to design gas cooler outlet temperature and transfers rejected heat from CO2 gas to ambient air and/or heat recovery fluid. 13. Discharge oil separator/reservoir unit (note 4) that separates compressor carry over oil from discharge gas, returns it to compressor units or store it in a built in or external reservoir section. 14. Oil level sensing devices/oil make-up valves (note 4) that sense oil level in compressor units and feed oil from oil reservoir to compressor units. 15. Oil recovery valve (note 4) that feeds a small stream of liquid from discharge of CO2 pump to suction of low temperature compressor unit upstream of low temperature suction heat exchanger.   16. Low temperature suction heat exchanger that provides heat to saturated suction gas and possibly liquid entering low temperature suction heat exchanger to evaporate liquid and slightly superheat gas leaving heat exchanger. 17. Intermediate temperature suction heat exchanger that provides heat to saturated suction gas and possibly liquid entering intermediate temperature suction heat exchanger to evaporate liquid and slightly superheat gas leaving heat exchanger. 18. Bypass pressure regulator (recommended component) that maintains pressure in intermediate pressure receiver at desired value when low temperature compressor unit is operating, and intermediate temperature compressor unit is not operating. 19. Refrigeration control system that controls components of the refrigeration system. 20. Interconnecting piping that connects components of the refrigeration system as depicted on the representative drawing (note 5).