Application of Rough Set Theory (RST) to Forecast Energy Consumption in Buildings Undergoing Thermal Modernization

Abstract

In many regions, the heat used for space heating is a basic item in the energy balance of a building and significantly affects its operating costs. The accuracy of the assessment of heat consumption in an existing building and the determination of the main components of heat loss depends to a large extent on whether the energy efficiency improvement targets set in the thermal upgrading project are achieved. A frequent problem in the case of energy calculations is the lack of complete architectural and construction documentation of the analyzed objects. Therefore, there is a need to search for methods that will be suitable for a quick technical analysis of measures taken to improve energy efficiency in existing buildings. These methods should have satisfactory results in predicting energy consumption where the input is limited, inaccurate, or uncertain. Therefore, the aim of this work was to test the usefulness of a model based on Rough Set Theory (RST) for estimating the thermal energy consumption of buildings undergoing an energy renovation. The research was carried out on a group of 109 thermally improved residential buildings, for which energy performance was based on actual energy consumption before and after thermal modernization. Specific sets of important variables characterizing the examined buildings were distinguished. The groups of variables were used to estimate energy consumption in such a way as to obtain a compromise between the effort of obtaining them and the quality of the forecast. This has allowed the construction of a prediction model that allows the use of a fast, relatively simple procedure to estimate the final energy demand rate for heating buildings.

Ecological and Economic Benefits of the “Medium” Level of the Building Thermo-Modernization: A Case Study in Poland

“…Finally, the set economic costs of thermo-modernization E ekon are summarized (Table 12) for the same eight thermo-modernization variants and for both buildings as in the case of ecological analysis. Similarly, variants (1) and (2) relate only to boiler replacement, variants (3) and (4) are associated with the very implementation of thermal insulation, and variants (5) to (8) are associated with boiler replacement and thermal insulation. Unfortunately, the economic costs of thermo-modernization came out positive in all variants.…”

“…This means that the economic costs of using the building will increase as a result of such a thermo-modernization investment. The lowest economic costs of thermo-modernization were obtained for variants (3) and (4), in which only thermal insulation is provided, both for the building B 1 and B 2 .…”

“…Szulc and Kokoszka [4] determined the energy characteristics of the studied buildings based on the actual energy consumption for heating. Calculations were made for the state before and after thermo-modernization.…”

“…The use of this method makes it possible to accurately determine the energy-saving potential for heating after thermo-modernization. The model developed on the basis of the fuzzy set theory turned out to be a universal solution [4].…”

Evaluation of Energy Efficiency in Thermally Improved Residential Buildings, with a Weather Controlled Central Heating System. A Case Study in Poland

“…These activities also include modernization and replacement of heat sources, replacement of windows and modernization of internal heating systems. In Polish conditions, according to the research carried out on a group of 109 multi-family residential buildings, for which energy characteristics were determined, based on actual energy consumption before and after thermal improvement, it was indicated that thanks to comprehensive thermomodernization, savings of 38-40% can be achieved [11], such a level of savings can be described as "average" [12,13]. Therefore, it is advisable to use other instruments to improve energy efficiency, through modernization and improvement of heat management-operational regulation in heating systems of buildings.…”