To resolve the complaints of occupants after entering a 28℃ room from outdoors, Kuno proposed the "cool room" concept. We evaluated its effects and the optimum duration in a cool room for the case of staying outdoors in the sitting position described in Part1. In this paper, we report on the experiments involving male and female subjects who performed outdoor walking. Subjects moved and stayed from outdoors, office space(28℃), cool room(24℃ or 26℃) to office space. Some subjects did not need the cool room. Therefore, we excluded those subjects and averaged the results to investigate the optimum duration for staying in the cool room. As a result, the optimum condition using fan was 5 min at 24℃ for males and 10 min at 24℃ for females. In addition, we created a calculation sheet to determine the necessary space area and proposed a design guideline for the cool room using the results of these experiments.

View full abstract

There has been a steady improvement in airtightness, but most clearly in newly constructed apartment houses. The high pressure difference in a residence between the indoors and the outdoors is a result of building envelope airtightness and mechanical ventilation. This paper describes the effect of high negative pressure difference caused by exhaust fans and airtightness on operation of housing equipment. In the present work, according to the usage of mechanical ventilation equipment, a high negative pressure difference of over -100Pa developed indoors. Noise from the air conditioner drain pipe depended on the installation conditions of the drain pipe. Verification test of seal destruction results indicated that, in addition to the effect of pressure difference, several factors such as the usage of a closet bowl are involved.

View full abstract

Increasing use of the Internet and ICT machines has increased demand of data centers. For stable operation of savers, which deal with huge amounts of information, air conditioning systems must have high efficiency and high robustness. Improvement of the airflow design is one of the effective measures to save cost and energy. Previous studies have focused on temperature distribution, but airflow distribution data must be collected to understand airflow in server rooms. Therefore, in this study, airflow distribution in a cold isle was measured using an actual size experimental model. In two airflow designs, one with both supply and return on the ceiling and the other with supply on the floor and return on the ceiling, the effect of control parameters on airflow distribution was investigated. As a result, the following facts are established. Decrease in the dimensionless air volume ・With the floor supply design, the supply air does not reach the upper side of the rack rows, the temperature increases from the upper side. With the ceiling supply design, the increase in the temperature is low, and the distribution of temperature and airflow is stable. ・With the ceiling supply design, the reverse height in the middle decreases, and it is confirmed that the supply air reaches the lower part of the racks. Besides, at the edge, the height does not change. Increase in the supply air temperature ・With the floor supply design and the ceiling supply design, the airflow distribution does not change. Increase of dimensionless length of hanged walls ・With the floor supply design, in the middle of the rack rows the reverse height in the middle of the rack rows does not change. Besides, at the edge of the rack rows, the invasion of hot air on the upper part is confirmed. ・With the ceiling supply design, the temperature in the middle of cold isle decreases. At the edge of the rack rows, the reverse height decreases, and the effect of the hanged walls is confirmed.

View full abstract