Improving the Energy Efficiency of Public Utility Buildings in Poland through Thermomodernization and Renewable Energy Sources—A Case Study

Abstract

Economical and efficient use of energy is promoted around the world as a model of conscious care for the environment in which we live. A mere change of habits in the use of energy can reduce its costs by 5% to 15%, and investments in energy-saving technologies can pay for themselves after just a few years. This case study shows how significant steps can be taken in saving energy in the building of public utility buildings through deep thermomodernization using renewable energy sources—compressor heat pumps and photovoltaics. The article presents a comprehensive thermomodernization of a school building made according to Polish regulations. A detailed description of the tested object is given, and the calculation procedure is described. Next, the optimal investment variant and ex post analysis are described. The implementation of these projects significantly improved the energy efficiency of the building and generated final energy savings of 80%, which will significantly reduce the school’s operating costs. Thanks to the applied improvements, it was possible to save 72.30% of thermal energy in the building, which directly translates into lowering the building’s operating costs. The improvement of energy efficiency indicators ranges from 66% for usable energy to almost 85% for non-renewable primary energy. Furthermore, by reducing the demand for energy used in the building by nearly 74%, we see a reduction in CO2 emissions. The methods used were desk research and an extended case study of Poland, a country facing a number of problems related to energy prices during the energy crisis. In this article, we identify the challenges faced by Poland due to its geopolitical situation, and the solutions introduced to the difficult situation in the energy market come in the form of the thermomodernization of buildings. It was on this basis that Poland was selected as a case study.

A Review of Energy Efficiency Interventions in Public Buildings

“…In recent years, the emphasis on energy-saving retrofits for educational buildings has gained significant traction [20][21][22][23]. A case study for a thermos-modernization of a school in Poland [24] reported significant energy savings. The building's heat consumption was reduced by 60%, its electricity consumption was reduced by 45%, and its hot water consumption was reduced by 75%.…”

Thermomodernization as a Mechanism for Improving Energy Efficiency and Reducing Emissions of Pollutants into the Atmosphere in a Public Utility Building

“…In publications on the impact of thermal modernization on energy savings in buildings of various types in the last 2-3 years, the results of energy efficiency improvements with the use of thermal modernization are most often presented in the works [24][25][26], along with the use of modernization of conventional heat sources with the use of renewable sources of energy, e.g., in hybrid systems [26][27][28]. An assessment of real energy effects was made on the basis of measurements carried out during the 4-year period of operation.…”

“…Table 3. Thermal parameters of external partitions before modernization against the technical requirements for buildings from the 2017 year (TC2017) and 2021 year (TC2021) (own elaboration based on [25,35,44]). The calculations were made in accordance with the PN-EN ISO 13790 standard and the methodology contained in the regulation of the Minister of Development and Technology of 15 December 2022 amending the regulation on the detailed scope and forms of energy audits and partial renovation audits, templates of audit cards, as well as an algorithm for assessing the profitability of a thermomodernization project.…”

“…The calculations determine the demand for heating purposes. We determine them from the relationship below [25,35,44]:…”

“…Another element is the energy used to prepare domestic hot water, and its demand is determined by the following formula [25,35,44]:…”