Study on Mechanism and Prevention of Thermal Discomfort Caused by Cold Outdoor Air through Supply Opening on the Wall (In the Case of Residence with various kind of Heating System)

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The research had been carried out since 1999 until 2000. The results obtained are as follows :(1) Questionnaire surveys The questionnaire survey of 86 residential buildings in the Kanto, Tohoku and Hokkaido district was carried out. More than half of residential buildings in the Tohoku and Hokkaido district have a problem of cold draft due to outdoor air, and then about 30% of them the occupant sometimes close their air inlets.(2) Field measurement in residential buildings In three residential buildings what installed mechanical exhaust system, measurement of air tightness, air exchange rate, air distribution and temperature distribution near inlet were carried out. Cold air infiltration was found in two residences.(3) Investigation on the air inlet Various inlets used inside and outside Japan were investigated and classified. Performance test of nine inlets were examined by using standard type small size wind tunnel. Information of inlet mechanism was documented.(4) Real scale experim … More ent using environmental chamber A real scale experiment in environmental chamber was carried out. The results are as follows, (1) The standardized vertical temperature difference is affected by the airflow directions from the supply opening. The highest value is observed for horizontal flow with maximum vertical temperature difference. The value increases in the flow directions of "vertical upward with an angle", "radial outward parallel to wall", "radial outward with an angle from wall", "horizontal outward from wall", sequently. (2) The standardized vertical temperature difference was examined in terms of various opening positions. The value of the difference decrease in the case of inlet installed above the window, in the upper, in the middle, in the lower of the wall sequently. (3) The influence of supply air velocity on vertical temperature difference was not significant.(5) Numerical analysis A full size room was adopted as the numerical model geometry. The standard k-ε model was used for the numerical simulation. Numerical result was compared with experiment, and accuracy was discussed. Furthermore, from the view points of air exchange efficiency and thermal comfort, air flow direction was also discussed. Less