Panasonic’s CO2 heat pump units replacing conventional HFC units
In recent years, the ozone depleting and global warming effects of fluorinated refrigerants have become a greater concern to the public in China. Among the alternative refrigerants available is the natural refrigerant CO2, which is a non-ozone-depleting refrigerant, has a global warming potential (GWP) of one, is non-flammable and also non-toxic.
Published in shecco’s comprehensive GUIDE to Natural Refrigerants in China 2015, case studies from Panasonic on its CO2 heat pump, specifically catered for workshop heating, and a heat pump water heater system for low ambient temperatures, are two such solution set to meet China’s demand for green solutions in the coming years.
Catering for low ambient temperatures at Dalian base
In the staff living quarters of Panasonic Appliances Compressor (Dalian) Co., Ltd. a CO2 heat pump system is used to provide hot water for security guards working the night-shift. The system is designed to accommodate 10 staff per day, assuming 100L hot water usage per staff member.
Previously, an electric boiler was used to supply hot water, which consumed more power and also suffered from scale formation within the system alongside other safety hazards contributable to the combination of electricity and water.
The use of CO2 in the heat pump is essential due to the northern location of Dalian, where the rated ambient temperature for heat pumps in winter is -12°C, and the minimum ambient temperature is -20°C.
Compared with heat pump water heaters using HFC refrigerants, the CO2 system is environmentally friendly and also has higher average hot water temperatures and lower capacity decreases in low-ambient temperature conditions.
- Compressor: 33F series CO2 DC-Inverter twin rotary compressor.
- Evaporator: copper pipe-aluminum fin heat exchanger with a small pipe diameter design to improve the pressure endurance performance and also decrease refrigerant consumption.
- Expansion valve: electronic expansion valve with real-time control by PLC based on the system operation parameters.
- Gas cooler: the double-pipe heat exchanger has been under intensified processing, improving the heat exchange efficiency with low flow resistance.
The CO2 heat pump isolates the water from electricity, reducing safety hazards, has proven to reach water temperatures higher than 65°C, even under -12°C ambient temperatures.
These results pose an incomparable advantage over heat pump water heaters using conventional refrigerants. Energy consumption is also 50% lower than a traditional electric boiler.
Panasonic Appliances compressor (Dalian) Co., Ltd is a Sino-Japanese company established in 1994. Their product line includes semi-hermetic compressors for commercial refrigeration and scroll compressors for commercial air conditioning. With Panasonic’s products being sold to 29 countries worldwide, the company has become a worldwide supplier for many leading manufacturers. With global sales of over 700,000 CO2 2-stage rotary compressors, these compressors have proven their excellent efficiency and reliability.