With global warming accelerating, growing attention is put on energy-saving devices that reduce CO₂ emissions. Since the early 1980s, Aisin Seiki has been working on development of commercial-use air-conditioning devices that use gas engines, which increase energy efficiency and reduce CO₂ emissions.

The situation at the time was similar to the one Japanese society is facing today–namely, summer electricity shortages. In the late 1970s, when Japan had recovered fully from the first oil crisis and the deepest recession since World War , record high temperatures led annual sales of residential air conditioners to exceed 3 million units, resulting in a situation in which available power capacity was insufficient to meet rapidly growing summertime demand.

As a result, research and development of air-conditioning technology that uses gas was designated by the government as a "Strategic Technology Support Project." Aisin Seiki, which had been working on technical development of Stirling engines^*, launched a program to develop commercial-use gas heat pump air conditioners (GHP) in partnership with gas providers, leveraging its expertise in engine technologies. In 1987, Aisin Seiki launched a 7.5 horsepower-class GHP into the market.

Since then, we have been developing products to increase efficiency and reduce size and weight to respond to the needs of society. We have sold 140,000 GHPs, such as the Mato Multi, to which two outdoor units are connected, and the High-Power Multi, which has a generator. Many schools, offices and retail premises currently use them. In the latest E-series, higher efficiency is achieved through optimal design of gas engines, compressors, heat exchangers and other key components. The line-up also features compact models that can be transported in emergency elevators.

* Stirling engine: An engine in which a sealed cylinder is alternately heated and cooled, resulting in expansions and contraction of air (air pressure change) that move the piston.

GHPs are not the only gas-fueled energy devices provided by Aisin Seiki that contribute to reduction of environmental load; we also provide gas cogeneration systems, in which electricity is generated using a gas engine, and heat generated during this process is utilized to provide hot water or room heating. A gas cogeneration system is a type of distributed energy system in which two types of energy, namely electricity and heat, are generated at the location in which they are used. Aisin Seiki launched the first such system in 2002 with a 6 kW commercialuse model.

In the case of commercial electricity generated at large-scale power plants, the long distance between generators and end users prohibits the use of heat generated during power generation. The utilization rate of primary energy is approximately 40%, taking into account energy lost during transmission of power to end users such as homes and workplaces. In contrast, gas cogeneration systems enable the use of heat generated during power generation to provide hot water or room heating, allowing energy to be utilized in a more effective manner with the total energy efficiency, including electricity and heat use, reaching 70% to 90%.

In recent years, we have been developing the residential gas cogeneration systems. In May 2011, we launched Coremo, the first of such systems, in regions supplied by Hokkaido Gas Co., Ltd. This system is used in combination with the Eco-Jozu^* energy-saving water heater, and provides electricity, room heating, and hot water in an efficient manner.

Upon switching on the room heating, Coremo’s gas engine automatically starts to generate up to 1.5 kW of power according to household electricity requirements. Heat generated in the process is immediately used by Eco-Jozu to heat water and for room heating, resulting in significant reduction in energy consumption and costs.

In general, the heat energy generated by the gas cogeneration system is greater than the amount of electrical power produced. Therefore, the key to increasing the overall energy efficiency is to utilize as much of the generated heat as possible. For this reason, we focused on Hokkaido, where demand is high for room heating using in-floor heaters and panel heaters, with approximately half of annual energy consumption in an average household going to heating. Thus, Coremo was developed as a system that caters to the lifestyle in Hokkaido, and allows energy to be utilized as efficiently as possible.

Use of Coremo and Eco-Jozu together reduces annual CO2 emissions by approximately 1 ton compared to a conventional gas-powered water and room heating system. Also, utilizing generated heat immediately and exclusively for room heating removes the need for a water storage tank, thereby saving space.

* Eco-Jozu is a registered trademark of Tokyo Gas Co., Ltd.