Contribution To The Short Measurement Method For Determining The Thermal Characteristics Of Existing Buildings: Total Heat Transmission Coefficient Estimation Based On Double Measurement

This article presents the way to determine the total heat transmission coefficient of a building based on double brief measurement and its practical application. It makes use of short measurement of heat consumption in a building and is based on the energy balance. In the proposed procedure the modified external temperature was used instead of the external air temperature. The modified external temperature takes into account the operation of solar radiation and wind on the building and the effect of resistance and heat capacity of the elements of the building envelope. The obtained results were verified by comparing the average monthly heat demand for heating calculated based on the determined total heat transmission coefficient and measured value. The presented way of total heat transmission coefficient determination in the event of a careful choice of measurement days and the experience of the user in estimating the number of air changes (especially in natural ventilated buildings) can be an independent method for determining HT^r based on short measurements. The procedure shown in this publication is also the element of current development of the method performed by the authors which leads towards a larger number of measurement days.