The European Commission's (EC) policy to phase out fossil fuels from the energy system has forced the reconfiguration of electricity systems (ESS) as a result of the large-scale introduction of renewable energy systems (RES). Achieving these objectives while ensuring energy security must lead to a balanced energy mix capable of ensuring an energy price that can be borne by end consumers, a goal that can be achieved by installing energy storage systems.

One of the important stages of energy efficiency measures for buildings is the optimal choice of heating and cooling systems, as well as that of heat/cold production sources, so as to minimize dependence on conventional fuels and the national energy system. Currently, the option for integrating renewable energy sources addressed in the building efficiency stage is the installation of solar systems. In the context of the need to reduce energy consumption and reduce pollutant emissions, and the need to integrate renewable energy sources, the article addresses the implementation of a hybrid system with a water-to-water heat pump and photovoltaic panels, capable of achieving the decarbonization of the heating/cooling of a University Politehnica Timisoara teaching/research laboratory. The analyzed hybrid system uses the thermal potential of the Bega channel as a heat/cold source, and as a source for electricity production, a PV system, supported by the national energy system. Following the analysis of the operation of the building’s hybrid system for heating and cooling, during 4 November 2024–12 September 2025, an energy independence of approximately 90.7% and a reduction in CO2 emissions of 4.17 t/year was found.

Given the energy crisis the entire planet is going through, the waste of any form of fuel or energy source is clear evidence of irresponsibility towards both humanity and the planet we manage. The study presents several proposals for making the district heating system more efficient by integrating renewable sources into the heat production process and recovering the residual thermal energy resulting from technological processes.

To achieve climate neutrality by 2050, new buildings, but also approximately 75% of the existing building stock in the EU, must begin the transition process towards decarbonization. The article models, analyses, develops and experimentally tests a hybrid technical system that provides heating, cooling and hot water for an educational building located in Timisoara, Romania. The hybrid system was designed by the authors to integrate renewable technologies for reducing operational CO2 emissions generated by technical systems in tertiary buildings. The hybrid system can provide, by PV system, 17.94% of hot water and heating agent for the winter season, and 78.61% of hot water and chilled water for building cooling in the summer season. The results obtained show a decrease in electricity consumption from the national energy system of 2.5 MWh. In terms of operational CO2 emissions, there was a reduction of 84.47% when compared with the classic system in which the building was connected to the city’s centralized system, which is currently dependent on fossil fuels (a coal and gas addition of approximately 10–15%).

Given the critical global context that has been reached in terms of air pollution caused by carbon emissions and other pollutants resulting from the combustion of conventional fuels, we urgently need to reduce the impact on the environment and find solutions that slow down global warming. Energy in various forms is a need that we cannot do without, but we must resort to primary sources that are as less polluting as possible and that at the same time ensure energy demand. Renewable energy sources must be exploited to the greatest extent possible and installations/equipment optimized for the highest possible efficiency. This paper presents the main conventional and unconventional energy sources, the evolution of their use over time and proposals for optimizing thermal and electrical energy production systems.

The paper analyzes the performance of an air-to-water heat pump installed in a single-family home in the hilly area of Romania, during the cold season.Based on in situ measurements and simulations, COP values between 2.90–3.54 for heating and 1.71–2.62 for DHW were obtained.The results confirm the efficiency of the system in low temperature conditions and reveal the importance of correct sizing and intelligent control.The study supports the use of heat pumps as a sustainable solution for residential buildings in cold climates.

As in 1973, the energy issue occupies the first page of the agenda of energy experts, social planners, politicians and, last but not least, consumers.The impact of renewable energy sources (wind and solar) on the energy infrastructure was analysed, while aiming to reduce carbon footprints.Demographic growth, urbanization, the targets imposed by Net Zero Emissions tend towards the massive forcing of energy towards renewable energy conversion and storage systems.

The increase in global temperature and the current energy context have brought the district heating system in Timișoara (partialy renovated) to the brink of collapse.Therefore, major investments and orientation towards the integration of renewable energy sources (RES) are required.The article analyzes, by exemplifying a case study, the integration of photovoltaic technologies at a heat point that supplies the buildings of the Faculty of Construction (CT) in Timișoara.The study was carried out with the help of Polysun software.The results obtained indicate a reduction in thermal and elctrical energy costs of 38.51% by installing a number of 1095 photovoltaic (PV) panels on the roof of 4 building bodies (ASPC, Deposit, CT and Metal).

In a residential building, the integration of thermal modules from the design phase can bring multiple benefits in terms of energy efficiency and thermal comfort.The article deals with a brief comparison between the traditional heating system and the decentralized system with apartment thermal modules by making the preparation of the thermal agent for heating and domestic hot water more efficient.The study was carried out following the new nZEB requirements regarding the obligation for all new buildings and those undergoing renovation to ensure a percentage of at least 30% from renewable sourcess.

eficiența sistemelor de termoficare.

Energy efficiency norms require effective insulation techniques for buildings in order to minimize energy consumption.The paper presents simulations, carried out throughout the year, regarding the efficiency of energy recovery units (ER) to ensure the quality of fresh indoor air.Indoor air energy recovery calculations were performed using plate and rotary heat exchangers in different operating scenarios.The evaluated parameters led to the stability of the optimization solutions in order to obtain a higher energy efficiency on the equipment.By comparing the obtained results, optimal measures and solutions were identified for energy efficiency in the operation of ER.

In an existing office building, integrating air-to-water heat pumps into a district heating system can bring multiple benefits in terms of energy efficiency and thermal comfort.The article deals with the implementation solution for the efficiency of district heating systems, exemplified by a case study related to an existing office building.The study was carried out following the multiple breakdowns that occurred in the thermal energy distribution system from the district heating company, as well as the interruption of thermal energy for long periods of time.

The study was carried out to evaluate theoretically and in laboratory conditions the capacity of a hybrid heating and cooling system that sustainably uses thermal energy extracted from surface waters in order to decarbonize buildings located near water sources. The novelty of the research consists in the realization of two experimental systems, one for the rapid evaluation of the performance of the water–water heat pump heating system and one for the evaluation of the operating behavior of a cooling system with fan coil units. Starting with the heating and cooling demand, and the climatic and hydrological local characteristics, a hybrid system model for the heating and cooling of the analyzed building was established and implemented. The forecasted energy consumption and CO2 emissions for the operation of the new equipment were compared with the historical values of the old systems with which the building was equipped (thermal energy supply from the district heating and cooling system with an air conditioning unit). Also, the results were extrapolated for forecasting the energy potential of the surface waters. The study highlights a percentage reduction in annual energy consumption of 67.71% and CO2 emissions of 80.13% through the implementation of the hybrid system.

In district heating networks, the influence of conditions: thermohydraulic, reliability, availability and cost of materials, heat demand and energy consumption for pumping, on the operation of the system must be considered in terms of optimizing the design so that the costs of production, transport and maintenance to be reduced as much as possible. These system problems are unavoidable during operation and therefore the paper proposes an analysis based on simulating the operation of the system in two possible situations: reducing the diameters of the heat transmission pipes with the compromise of increasing the energy consumption required for pumping and respectively reducing the maximum pressure losses with the advantage of obtaining an energy saving at pumping. The comparison of the results obtained by the simulation allowed the choice of the optimal solution established on the basis of the minimum total costs (capital and operational) and the minimum heat losses on the pipeline network, taking into account the variation of investment costs of the pipeline and pumping energy depending on the diameter of the pipe.