Press Release Back Number(2005)

Chubu Electric Power develops high output heat pump unit employing CO2 coolant for regions with severe winters
- Allowing production of EcoCute water heaters with 460-liter hot water tanks designed for cold regions -

April 25, 2005
Chubu Electric Power Co., Inc.

In an industry first, in conjunction with Denso Corporation, Chubu Electric Power has developed a high output heat pump unit*1 for EcoCute*2 heat pump water heater offering 6 kW of heating capacity with outside air temperatures as low as minus 20°C.

  1. *1 The heat pump unit draws heat from the outside air and employs it for efficient hot water supply and room heating. Heat pump unit components include a compressor and heat exchanger.

  2. *2 "EcoCute" is the nickname used by power companies and manufacturers of electric water heater for heat pump water heaters that use natural coolants.

Because EcoCute water heaters use heat from the air to boil water, until now, models used in areas with severe winters have been limited to a heating capacity of 4.5 kW and hot water tanks of up to 370 liters.

This led to calls from customers in regions prone to extreme cold for larger hot water tanks for EcoCute water heaters, and use of the heaters for room heating.

In response, as well as developing a compressor capable of withstanding the high pressures required to boost the coolant circulation?in order to improve heating capacity with low outside temperatures, and raise the heating capacity to 6kW under these harsh temperature conditions?we developed a heat pump unit that, for the first time, employs an ejector*3.

  1. *3 Fluid pump that uses the kinetic energy released through expansion of coolant to supply auxiliary power for the compressor.

This latest development will allow commercial production of an EcoCute water heater with a 460 liter tank for regions with severe winters. In future it is expected that the unit will also be employed in multifunctional EcoCute water heaters with a room heating feature.

Denso Corporation plans to supply the new heat pump unit on an OEM*4 basis to several EcoCute manufacturers.

  1. *4 OEM: Original Equipment Manufacturer - Contract production of products to be sold under the client's brand name.

The new heat pump unit developed by Chubu Electric Power and Denso Corporation offers the following features.

  1. (1) High output even in severe winter regions!
    Boils even when the outside temperature is minus 20°C, providing 6 kW of heating capacity at 90°C.

  2. (2) New high efficiency freezing cycle!
    Employs an ejector to achieve an industry-best COP*5 rating of 4.5.

  3. *5 COP: Figure obtained by dividing water heating capacity by power consumption. The higher the number, the greater the energy savings.

  4. (3) Improved product lineup!
    Allows production of EcoCute water heaters with 460 liter hot water tanks for regions with severe winters.