No abstract

Various methods can be used to reduce energy consumption in buildings. One of them is the tightening of energy requirements, which, like other methods, cannot result in a worsening of the indoor environmental quality. The article presents a study on the impact of changes in the thermal insulation of the building envelope on the energy demand, heating costs, and emissions. Mathematical models of the dependence of the index of annual usable energy demand for heating (EUH) of a residential house on the thermal transmittance coefficients (Ui) of selected building elements were developed. Values of Ui were adopted at three levels, corresponding to the maximum required values—as approved in Polish law for the periods from 2014, 2017, and 2021. The analyses were conducted for the location of the building in three of the five climate zones of Poland. It turned out that the differences in the energy demand in various locations in Poland amount to 32.6%. The change in Ui in the analyzed period causes a decrease of EUH by almost 27%. Financial savings and a reduction of emissions strongly depend on the fuel used in the building. Increasing the level of thermal insulation of walls increases the perceptible temperature in rooms by 1.2–1.5%.

Abstract. Deterioration of concrete due to surface scaling is a very serious durability problem faced by the construction industry in cold environments. The experimental results of resistance to scaling due to cyclic freezing and thawing in the presence of 3 % NaCl solution (de-icing agent) of not air-entrained concrete with and without bituminous addition are presented and discussed in the paper. The results have been analysed using the analysis of variance and regression to verify the effect of addition content, number of freeze-thaw cycles and the sort of cement on concrete ability to scaling. The statistical analysis showed that the bituminous addition significantly improves the scaling resistance of Portland cement concrete.

This work presents the results of analysis of the final energy demand (Qk) for a single-family house in a pandemic situation and accompanying self-isolation of residents. It was assumed that the object of study is located in Bialystok (Poland). This analysis covers the impact of various factors such as specific periods of the active pandemic phase, the length of the inhabitants’ self-isolation period, the number of residents at home, and the type of energy source used in the building. Based on the results of computational experiments, a deterministic mathematical model of the relationship between these variables was developed, and the effects of the selected factors on the final energy demand were analyzed for the typical meteorological year (TMY) weather data. It turned out that the change in the length of the self-isolation period from 0 to 31 days caused an increase of Qk by about 6.5% for the analyzed building. When the number of inhabitants changed from 1 to 4, Qk increased by 34.7%. A change from 4 to 7 people causes an additional 26.7% increase in Qk. It was found that the structure of energy demand for this building operation during the period of inhabitants’ self-isolation also changed. With the increase in the length of the self-isolation period from 0 to 31 days, the electricity demand (Eel) increases by about 40–42%, while the demand for energy related to fuel consumption (Qg) decreases by about 7–10%. The article also presents an analysis of the impact of residents’ self-isolation on indoor air quality (IAQ) and thermal comfort. The simulation results showed that the use of variable air volume ventilation allows the CO2 concentration to be kept significantly below the limit value.

Artykuł dotyczy analizy rozwiązań złożonych mostków termicznych, występujących w węzłach mocujących elewacji wentylowanych oraz sposobu ich uwzględniania w obliczeniach cieplnych. Na podstawie tej analizy wykryto szereg czynników, które mogą wpływać na parametry cieplne mostków termicznych, jednak nie są one odzwierciedlone we wzorach z aktualnych norm. W związku z tym należy szukać nowych podejść i zależności, które w sposób precyzyjny pozwolą określić parametry fizyko-techniczne podobnych węzłów mocujących.