In recent years, due to the rapidly growing global energy crisis and the ever-increasing prices of energy carriers, more attention has been paid to the energy efficiency of existing buildings, especially in the context of reducing harmful emissions and lowering heating costs. The purpose of this study was to analyse the influence of selected factors on heating costs and air pollution in a cold climate based on the example of a service building located in Bialystok, Poland. The following scenarios were assumed: the implementation of a heating schedule, improvement of the thermal insulation of the building envelope, lowering of the indoor temperature in all rooms, and moving away from a traditional heat source (gas boiler) to renewable energy (heat pump). The results showed that improvements in heat transfer coefficients had the greatest impact on reducing heating costs and that emissions from renewable energy sources depend largely on the national energy mix.

Heat pumps, an example of one of the most environmentally friendly technologies, can play a key role in the future of sustainable energy. Due to the European Union’s ambitious goals to achieve climate neutrality by 2050, research is currently focused on finding solutions to increase the energy and economic efficiency of heating and cooling with heat pumps to benefit the environment. This paper presents the results of energy simulations for a single-family building located in selected cities—Warsaw (Poland), Madrid (Spain), Riga (Latvia), and Rome (Italy)—as a case study for different climate conditions and energy policy. In each variant, ground and air source heat pumps are considered for heating, cooling, ventilation, and air conditioning (HVAC) purposes. Moreover, we conducted an economic estimation including investment and operating costs, as well as an ecological analysis of carbon dioxide (CO2) emissions. Results show that heat pumps as an energy source for HVAC systems seem to be much more beneficial for Mediterranean-type subtropical climates, than for continental-type climates. The lowest value of total energy demand was obtained in Rome (60 kWh/m2∙rok), while the highest values were recorded in Riga and Warsaw (more than 90 kWh/m2∙rok). In terms of economic and environmental aspects, the use of heat pumps was most advantageous when considering Rome. This paper provides a starting point for further research focusing on increasing the energy and economic efficiency of heat pumps, especially in cold climates, as well as a multi-parameter analysis taking into account national prices, policies regarding development of renewable energy sources, and technical and climatic conditions. It also shows how increasing the share of renewable energy sources (RESs) in the national energy mix contributes to the reduction of CO2 emissions.

Heat pumps are increasingly popular in individual buildings and could help to meet expectations of ambitious energy-environmental European goals until 2050. This paper presents the results of energy simulations conducted in TRNSYS for a single-family building depending on its location in selected European cities. For each city, air source heat pump (ASHP) was considered as an energy source for heating and cooling the building, and then an economic analysis was carried out including investment costs of air source heat pump and a comparison of operating costs of ASHP with other alternatives (i.e. gas boiler, oil boiler, or air conditioners). The results of the simulations showed that with the current energy prices the use of air source heat pumps is the most beneficial in temperate warm transitional climate (Krakow). It was also indicated that the implementation of special tariffs (reduced prices) for electricity that supplies renewable energy devices would make heat pumps unmatched as a source of heating and cooling in the residential sector.

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With the prevailing energy crisis and the public’s growing environmental awareness, renewable energy sources (sun, wind, water) are playing an increasingly important role in Europe and around the world. Due to its easy availability and relatively high efficiency, it is the solar energy that is attributed with great potential in decarbonizing the energy sector. Among the most popular devices that enable the use of solar radiation are solar collectors. They are used in heating and domestic hot water preparation systems, as well as for heating swimming pool water. However, their efficiency depends on many factors, of which the main one being the climatic conditions. This paper presents the results of energy simulations of a solar collector-based domestic hot water system for the capitals of five selected Central and Eastern European Countries (CEEC) – Riga (Latvia), Warsaw (Poland), Prague (the Czech Republic), Bratislava (Slovakia), and Zagreb (Croatia). The system model was developed using the TRNSYS software, in which dynamic simulations were also performed for an entire year (8760 h). For each location, the efficiency of the flat-plate solar collectors, the amount of useful energy generated by them, as well as the amount of energy needed to meet the load and auxiliary energy requirements were analyzed and compared. The extent to which increasing or decreasing the area of solar collectors affects the operation and efficiency of the system for different locations was also estimated. The results showed that in terms of efficiency, the use of solar collectors is most favorable in Slovakia and placed southernmost-located Croatia, where it also achieved the lowest annual auxiliary energy demand. The least favorable location, on the other hand, turned out to be the capital of Latvia. It is also worth noting that regardless of location, the area of solar collectors has a significant impact on the efficiency of the entire system.