Experimental evaluation of effective envelope heat transfer coefficients in multifamily buildings

The evaluation of energy conservation measures for buildings requires a detailed breakdown of heat losses. One of the major heat losses occurs through the building's envelope. Overall heat losses from single family houses have been measured by electric co-heating where the heating system is replaced by electric heaters. This method is impractical for large multifamily buildings. The present paper discusses an experimental procedure which makes use of the electric co-heating method for a sample apartment of the building, while properly addressing the problems associated with the nonnegligible heat transfer between the sample apartment and its neighbors. Measurement strategies are dictated by the requirement of minimizing the experimental errors. The effective heat transfer coefficient is determined from a steady-state energy balance, averaged over many days.