2017 Volume 30 Issue 6 Pages 244-252
A new estimation method of heat loss coefficient for existing buildings is proposed. The method is focused on the heat loss through convective heat transfer, because the air infiltration is negligible in the buildings and the ventilation is controlled by the building Heating, Ventilation and Air Conditioning (HVAC) controller. The heat loss coefficient (Q-value) evaluation of the existing houses are reported in the prior arts and the energy performance of the existing buildings has been reported as one of the commissioning process. The methods enable the total energy performance, but they do not clarify the week insulation elements. In order to visualize the energy flow easily, the proposed method identifies system parameters based on the data-oriented building heat loss model,using heat transfer engineering, with the interior wall surface temperatures and room temperatures that are easily obtained. The correction factor is obtained for the window natural convection heat transfer, because the empirical heat transfer equation for the week natural heat transfer contains some inaccuracy.