Evaluation Method for Thermal Environment in Residential Houses Using Score on Warmth

The purpose of this study is to verify whether the score on warmth corresponds to the actual rating of subjects with regard to thermal comfort and satisfaction. Experiments were carried out in an experimental house in a climate chamber under five different thermal conditions, in which different combinations of air and floor temperatures were controlled by floor heating or air-conditioning systems. Twenty-four subjects rated their thermal sens2ation and satisfaction in each condition, and evaluated the thermal environment on a 100-point scale. The results of this experiment are as follows. It was suggested that score on warmth based on operative temperature and floor temperature more appropriately evaluates the living environment in Japan than the Predicted Mean Vote model, which assumes uniformity of the thermal environment. The score on warmth is considered a useful thermal environment index, which evaluates the comfort and satisfaction of residential houses in Japan. The score on warmth was 2.8 points when the percentage of comfort rating was more than 80%, and was 3.0 points when the percentage was more than 90%. In conclusion, these results show that it is possible to predict the risk of catching a cold in winter using the score on warmth

Efficient Operation of Heat Source using High-temperature Chilled Water in an Advanced Office Building

In recent years, energy conservation has become a major focus in the industrial sector. Many office buildings in Japan achieve energy savings by introducing highly efficient equipment and systems, such as high-temperature cooling water (14 °C), which increases heat source efficiency. However, such equipment requires adjustments to increase operational efficiency. In this case study, the efficiency of equipment using high-temperature cooling water was further improved through operation control optimization. The energy efficiency before and after the improvement was compared. The target building has chilled and hot water supplied to each floor from district heating and high-temperature chilled water supplied from cooling chillers on the rooftop. The energy consumption of two floors was evaluated: a subjective floor with equipment using high-temperature cooling water installed, and a common floor with a conventional system. After on-site verification, changes were made to the operation control of the cooling towers, condenser pumps, primary pumps, secondary pumps, and air handling units. As a result, the coefficient of performance of the water-cooled chiller and the whole system improved by 0.40 and 0.45, respectively. The flow rate of the air conditioning equipment using high-temperature cooling water decreased while maintaining an equivalent amount of heat extraction. In conclusion, the efficiency of the equipment was further improved by operation control optimization