The dissertation is devoted to the comparison, adaptation and development of methods for estimating energy efficiency of buildings on the basis of mathematical models taking into account the dynamics of changing environment conditions. A literature review of modern trends in the use of mathematical modeling and normative base on approaches to assessing buildings energy efficiency is performed. The need to reduce the time intervals of calculation is shown, taking into account the specifics of the use and development of dynamic methods for calculating energy need for heating and/or cooling.
The analysis of characteristics and modeling of building thermal state was carried out on the basis of various mathematical models for public buildings of various complexity, regional location, year of construction and conditions of operation. In the conditions of energy carriersefficient use, energy need for heating should be calculated taking into account hourly changes in climatic characteristics that cannot be realized in stationary models. Dynamic models for determining buildings energy performance require the use of hourly climatic data (for Ukrainian cities - typical year of the IWEC).
Mathematical models for the research of energy status of buildings use end-points characteristics of influence, such as air exchange rate, solar heat gains to the space area, and others, which require recalculation methods. Averaged monthlyobtained results are compared with the normative climatology of Ukraine for the city of Kyiv and Odesa. The difference is 40% in the winter and 30% in summer for Kyiv, and for Odesa it is up to 50%.
The peculiarities of the considered methods use and application of various averaging time intervals of the initial parameters are determinedas an influential parameter on the research results. Dynamic E + and 5R1C methods give almost the same value for energy need for heating, the difference is up to 4-8%, in cooling mode it is up to 16-18% with IWEC climatological data. The buildings intermittent modes of heating were investigated on the basis of dynamic models and the possible range of energy savings for different temperature schedules of premises was determined taking into account the recommended temperature difference during non-working hours, which is about 9%.
In the paper, the experimental and calculated determination of the integral and scattered characteristics of the thermal and energy state of the building is carried out on the basis of long-term observations (2003-2017). Data on temperature distribution in the premises of a multistory building of an educational facility were obtained, depending on their location, use and level of heating. The combination of calculated and experimental data allowed to determine the air exchange rate on the basis of the created multi-factor regression model and actual values of internal temperature, heating level and solar heat gains.
Ukraine has two standards for defining the buildingsenergy efficiency class. A new energy scale of 14 classes for buildings energycertification for public facilities located in small towns and villages is proposed, which is based on certain reference points and allows to assess the buildings energy efficiency when implementing energy-saving projects.
Key words: energy need, energy efficiency, buildings, mathematical model, temperature, heat gains, climatology, energy certification.
