Heat Flows in a Full Scale Room Exposed to Natural Climate

An ambient wall with a window were studied with both theoretical analyses and measurements performed
under conditions with natural climate. The method used wes to estimate the heat flow through wall and window
from measured temperatures and solar radiation. The longwave radiation was calculated from surface temperatures. The convective heat transfer was caculated as the difference between the heat flow through the building element and the longwave radiation. With the one-dimensional dynamic heat transfer model for the window which included shortwave radiation it was possible to measure the continuous heat flow through a window from temperature sensors and solar radiation measurements. With the one-dimensional finite difference model for the heat transfer through the wall it was possible to calculate thre heat flow through a wall from temperature sensors. It was possible to continuously measure the convective heet transfer coeffìcient on the inner surface of a wall or a window, The accurary was not very good: at best +/- 15% for the window and, +/- 20% for the wall. Even with this low accuracy the effect of different heating and ventilation strategies on the inside could clearly be detected. The results showed that the importance of the ventiletion design and the position of the radiaton is crucial. Local convective heat transfer coefficients may be more than 10 times the expected, due to ventilation or position of the radiator.