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In continental climates heating accounts for a significant part of the total energy consumption of a residential building with average thermal characteristics of the envelope. Solar heat gains have to be used wisely in order to reduce the energy need for heating. Glazed ratio of the facades, orientation of the transparent area and thermal mass has to be properly chosen in order to obtain the desired utilization factor. In this paper the effects of window size, thermal mass and window orientation on the balance point temperature are analysed in case of a reference room. The calculation methodology given by EN ISO 13790 standard was used. Measurements were done in order to validate the model. Performing the calculus on 48 different cases it was shown, that differences of even 11% can appear between the energy demands for heating (for similar overall heat transfer coefficients of the external building elements). [ABSTRACT FROM AUTHOR]

In all European countries the energy and building related legislature stand for energy refurbishment of existing building stock. Depending on the economical situation of countries there are different national programs that help owners to invest in energy related refurbishments of their houses or flats. The financial support is given only in case of a certain payback time, which should be obtained by the proposed project. The payback time for heating related investments in Hungary is calculated based on the theoretical degree day curve, which can lead to inaccurate results. Thus in this paper a long-term analysis of heating degree day, done for Debrecen (the second largest city of Hungary), is presented. We focused our analysis on residential buildings. It was found that the degree day has important variations during the analysed decades, which can lead to deviations of energy consumption up to 15–18%. Furthermore, taking into account the heat island effects in Debrecen, it was proven that differences of about 22% can be obtained between real degree day values in different zones of the city. The interrelation between specific heat gains and balance point temperature, respectively the effects of glazed area of the facades on the balance point temperature was discussed. It was found that for buildings with similar thermal characteristics of the envelope and the same values of specific heat gains, the balance point temperature can be even double for a detached house compared with a block of flats. [ABSTRACT FROM AUTHOR]

In Central European countries, heating represents approximately 75% of the total energy use of a residential building, with average thermal characteristics of the envelope. The expected energy use can be determined using complex simulation programs, but an easier way is to use specific degree day values. Degree day values should be calculated as precisely as possible. At present in Hungary, the degree day values that are used for simplified energy calculations were determined several decades ago. The aim of our research was to determine the degree day values based on the last 60 years for different Hungarian settlements. Using the CarpathClim database and elaborating the degree day values for 25 Hungarian cities, differences of 10% have been found compared with the values used previously for energy calculations. [ABSTRACT FROM AUTHOR]