Estimation of the changeover times and degree-days balance point temperatures of a city using energy signatures

Knowing when to change the mode of a Heating, Ventilation and Air Conditioning (HVAC) system between heating and cooling (the changeover time) is of great importance. Instructions for estimation of this time for buildings are provided in the literature, but there is none on estimating the changeover time for a city. In this paper, using base temperatures of degree-days (balance point), a method for estimating the starting point and endpoint of seasons is introduced. Base temperatures are different for different cities with their own weather, buildings constructions and energy consumption behavior. The new developed method based on the energy signatures is capable of predicting the changeover time and base temperatures of a city. Energy signatures which are obtained by daily energy consumptions have been used for the first time for an entire city to find the base temperature in this paper. The results show that the base temperatures for Kerman city are different from the common ones used before. A six degree curve is fitted to the average daily temperatures for each year, and the seasons start and end times are found using the curves and the base temperatures.