The efficiency of a typical meteorological year and actual climatic data in the analysis of energy demand in buildings

A typical meteorological year (TMY) for Poland was developed in 2004, on the basis of climatic data collected from 1971 to 2000. Due to the observed tendency of global warming, the buildings' energy performance obtained with the use of TMY may differ from the actual heating and cooling demand. This research compares energy demand calculated using TMY and climatic data collected from 2001 to 2012. Calculations were made by means of a simulation computer program, designed for dynamic analyses of buildings and installation systems. The analyses concerned typical living quarters in a multifamily residential building located in Warsaw. According to the results, TMY is useful for estimating the heating demand of existing buildings. Cooling demand calculated with the use of TMY was, however, up to 37% lower in comparison with the mean cooling demand for subsequent years. This may distort the energy needs and indoor environment conditions in summer, and create discomfort while using existing and new buildings.Practical application: The paper presents comparison between energy demand calculated with the use of typical meteorological year (TMY) based on the climatic data from the period of 1971 to 2000, and real climatic data from subsequent 12 years, 2001-2012. There is substantial difference in the results presenting cooling demand in buildings evaluated with the use of both datasets. Unless national energy certification procedures are updated, this may cause serious faults in building design, due to incorrect assessment of internal conditions in new and existing buildings, and higher than expected energy use in summer.