Amid increasing global energy prices and growing air quality concerns in Asia, particularly China, it comes as no surprise that CO2 heat pumps are now seen as the next generation solution for the application.
Mitsubishi Electric, Hitachi Appliances, Nihon Itomic and Showa were among the suppliers showcasing their latest technology at the event held on 23-26 February. Takashi Mikubo of Itomic echoed the sentiments of most by saying:
“CO2 is the optimum refrigerant for heat pump applications because it can heat water up to 90°C at the same efficiency as Freon refrigerants at 50°C.”
Noriyuki Ueba, a heat pump specialist at Hitachi Appliances, highlighted the “top class” COP of 4.2 for its 15kW heat pumps. Since 2004, Hitachi has sold one thousand units.
Hitachi’s 15kW hot water heat pump contains two 2.6kW Hitachi compressors and an Alfa Laval heat exchanger to enable pinpoint regulation of high pressures.
“Hitachi is trying to drive the price down,” Ueba said. “There is nothing we can do about competition, but it is good to drive the price of CO2 technology down.”
Mitsubishi heat pump eliminates scaling
Hitoshi Nakamura, manager, marketing department for heat pumps at Mitsubishi Electric, described the fitted technology as a “scaling-inhibiting system”.
The unique system eliminates scaling of the heat exchanger, which is a particular issue in hard water conditions like those in China.
This was clearly on display through a glass casing on Mitsubishi’s 40kW CO2 heat pumps, which Nakamura said have a COP of 4.0 and can heat water to 90°C.
Nakamura said the company would like to export the systems to other regions but that China is “difficult in terms of cost because of the lack of subsidies and support from the government”.
Domestic heat pump technology
Representatives from Itomic disclosed impressive sales figures for their 30kW and 60kW CO2 heat pumps on display, with 2,000 in Japan and a further thousand globally, which is said to include the first commercial installation for a CO2 heat pump. The company’s range also includes a 10kW version that was not on display in Tokyo.
Itomic reported that many of its clients had benefited from Japan’s Ministry of Economy, Trade and Industry’s (METI) subsidy programme for energy-efficient technology.
The company is selling approximately 20-30 units a year in China, in most cases a direct replacement for polluting coal-fired heat pumps. However, the company’s focus in China is more on heating than hot water for domestic/commercial applications.
Meanwhile, Showa’s improved SSHP – 30B CO2 heat pump comes with a COP of 3.2 and has already pre-sold 100 units ahead of its release in April 2016. The company has sold 1,000 units of its older model.