The article simulates the impact of the complex application of energy-saving measures on the energy efficiency indicators of a public brick building. During modeling, the economic factor – capital investment in energy saving measures – was taken into account. Similar simulations are carried out during energy audits of various types of buildings. Performing energy audits of residential and public buildings in the city is, in accordance with the Law of Ukraine “On Energy Efficiency”, an important part of Ukraine’s energy conservation policy. Energy audits are required for: a) development of an energy certificate, which is required for many new and existing buildings in accordance with current legislation; b) attraction of funds from the energy efficiency fund and other funds for the needs of thermal modernization; c) obtaining reasonable indicators that will allow building owners to make energy-efficient decisions. The energy audit report contains three stages: the stage of obtaining information, the stage of analyzing information and developing energy-saving recommendations, and the stage of technical and economic substantiation of the proposed energy-saving recommendations. At the first stage, energy auditors collect raw data about buildings. Existing buildings are often characterized by the lack of insulation of opaque enclosing structures, the presence of translucent enclosing structures, the reduced heat transfer supports of which are significantly lower than the minimum permissible values, and outdated sources of heat supply. During the second stage, mathematical models are developed that allow obtaining technical and economic indicators of energy saving measures. The third stage is the substantiation of optimal measures that must satisfy technical and economic constraints. The work analyzed the dependence of the general indicator of specific energy consumption during heating and cooling of a two-story brick public building under the condition of modernization of the gas boiler, as well as insulation of the brick facades of the building with polystyrene foam plates of different thicknesses. At the same time, an analysis of both individual and complex application of the specified measures was carried out. General capital investment in thermal modernization was adopted as an economic indicator that sets limits on energy saving measures. As a result of the modeling, it was established that in order to determine the optimal measures to increase the energy efficiency of the building, it is necessary to use optimization mathematical devices that take into account the existing restrictions and can be integrated into mathematical models that calculate the basic level of energy consumption in compliance with the normative parameters of the building’s operation.

The issue of energy saving is becoming more and more urgent, taking into account the destruction of power generating facilities. One of the energy saving options is the use of alternative energy sources. This is not only an economic benefit for consumers, but also a reduction in the load on electrical networks and maintenance of the reliability of the power system due to the decentralization of electricity generation in wartime conditions. Alternative sources of electricity include energy from the sun, wind, seas, rivers, biomass, and Earth’s heat. At the same time, their effectiveness depends on many factors. Since Ukraine has a powerful industrial agricultural complex, its share in GDP is about 10% and its share is growing annually, therefore, an urgent task is to analyze the feasibility of using biogas plants at livestock, agro-processing and municipal waste enterprises. We should not forget about the environmental friendliness of electricity production using biogas plants, which will ensure the preservation of the environment, and therefore the health of descendants. Enterprises of the agro-industrial complex for the production of products require significant amounts of electrical energy, along with this, the waste of the activities of such enterprises is sewage and organic waste in landfills, from which biomass can be obtained. Biomass, in turn, is the raw material for the production of biogas, which is needed by biogas plants to generate electrical energy. Analysis of the amount of waste from agro-industrial complex enterprises, which can be used as raw materials for the production of biogas, showed that Ukraine has prospects for the development of biogas energy, based on a powerful agricultural sector. The use of biogas plants will provide electricity, heat and hot water to enterprises of the agrarian complex, and will reduce the load on traditional energy sources.