Press Release Back Number(2004)

Introduction anticipated for Japan's largest 70 kW-class air-source heat-pump system incorporating CO2 cooling medium, targeting commercial applications

September 7, 2004
Chubu Electric Power Co., Inc.

Chubu Electric Power and Mayekawa Mfg. Co., Ltd.*1 have jointly developed a heat-pump system that uses CO2 as a cooling medium, targeting commercial applications that require a steady supply of hot water. The system has a heating/cooling capacity of 70 kW and uses environment-friendly CO2 refrigerant. Commercialization of the system is expected in the near future. The system is designed for hospitals, hotels, sports facilities, and various food and beverage plants that use large volumes of hot water.

Among water heaters using CO2 coolant, EcoCutes with capacities of 5 kW and 25 kW have already been introduced to the market, winning widespread acceptance for their energy efficiency. Chubu Electric recently developed a large reciprocal compressor capable of providing the high pressure required by a water heater using CO2 refrigerant, marking a first in Japan, and has successfully commercialized a 70 kW heat-pump system that provides heated water at high temperatures. The latter heat pump system is the largest air-source heat pump system in Japan. This development enables use of electrical equipment in the market for high capacity equipment, where only gas-powered units had formerly been available.

The features of the newly developed hot-water supply heat-pump system are given below:

  1. 1. Highest hot-water supply capacity in Japan (among air-source heat pump systems using CO2 as coolant for hot-water supply)


This 70 kW capacity hot-water supply heat-pump system uses CO2 coolant and can generate water at high temperatures (90°C).

  1. 2. Dramatically reduced start-up times


The time elapsed from system startup to actual supply of hot water has been reduced by 78% (relative to conventional units) to 26 seconds (when supplying water at 65°C)*2.

  1. 3. A global environment friendly system with low operating costs


Annual operating costs are approximately 61% lower than for a gas-powered hot-water boiler*3.

Annual carbon dioxide emissions (greenhouse gas emissions) are around 53% lower than for a gas-powered hot-water boiler*3.

  1. 4. Simultaneous heating and cooling extraction through "high temperature hot-water supply" and "ice thermal storage system"


Permitting simultaneous use of a high temperature (90°C) hot-water and ice thermal storage system (ice-making capacity of 48 kW), This heat-pump system is capable of meeting the needs of hospitals, hotels, and food production plants, all sites that require simultaneous hot water supply and cooling systems.

*1 Mayekawa Mfg. Co., Ltd.: President: Isao Iwade, Address: 2-13-1 Botan, Koto-ku, Tokyo

*2 Actual figures at rated conditions of JRA 4050:2004, a standard issued by the Japan Refrigeration and Air Conditioning Industry Association

*3 These figures are based on a hot water supply temperature of 90°C, hotel load (source: the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan) and annual temperatures for Nagoya, Japan.