Development to improve energy efficiency of floor heating systems with thermal comfort

摘要

Gas hot water floor heating systems are highly appreciated for their features such as creating a comfortable thermal environment to keep the head cool and the feet warm and they are being installed increasingly, mainly in new residences, in recent years. Despite the high comfort level, this type of heating system is required higher level of energy efficiency by Japanese energy conservation standards. This paper describes the technical development to raise the energy efficiency of floor heating systems to meet the above-mentioned standards. At the same time, we also focus on the energy saving effects caused by the thermal comfort of floor heating systems. We aimed to increase the efficiency of the burner by connecting the floor radiant panels of two separate rooms in series to increase heat release and enlarge the temperature difference between supply and return fluid. Also, by installing vacuum insulating material on the underside of the floor radiant panels, we aimed to increase the indoor heat release rate. In addition, by combining the gas cogeneration and the ganged control system of the room air conditioner and the floor heating, we were able to power the air conditioner with electricity generated by the cogeneration, and use the exhaust heat of the power generation to warm up water for the floor heating. In this way, we aimed to reduce the amount of energy lost. We also introduce that when using floor heating, because the whole body is warmed from the feet up by radiation and conduction of heat from the floor surface, the necessary room air temperature to achieve an equivalent level of thermal comfort can be set at approximately 2°C less than when using room air conditioner [1].