scholarly journals Effects of thermal bridges on the heat demand of residential buildings

2021 ◽  
Vol 664 (1) ◽  
pp. 012100
Author(s):  
D D Sabie ◽  
A-G Ghiaus
2019 ◽  
Vol 97 ◽  
pp. 01041
Author(s):  
Adam Ujma ◽  
Marta Pomada

Designers more and more often choose facade systems with ventilated layers for external walls, especially in the case of new buildings. They are also used to modernize existing buildings. Mechanical connectors are a characteristic element of these constructions. Often, they are ignored in calculating the heat balance of rooms and the entire building. Because they pierce the thermal insulation layer they cause point thermal bridges. The influence of thermal point bridges, usually made of aluminum, i.e. a material with very high thermal conductivity, for heat transfer turns out to be significant. Such thermal bridges significantly increase heat losses through building partitions. This situation increases the heat demand in the rooms to compensate for the heat loss. The article presents the results of the analysis of the impact of mechanical fasteners in ventilated facade systems on heat transfer in the building envelope. The influence of various materials and constructional solutions on the thermal conditions in these walls was investigated.


2018 ◽  
Vol 49 ◽  
pp. 00088
Author(s):  
Kamil Różycki

This article presents the energy balance conditions of three multi-family residential buildings located in Kryvyi Rih, Ukraine. These buildings were built more than 40 years ago and are not insulated. A significant amount of energy is lost by the external partitions. The building’s heating is powered by municipal natural gas. A proposal for several thermomodernization variants for selected facilities are presented in the article. These variants of deep thermomodernization include an upgrade of the heating installation, insulation of external walls and roof, and the replacement of windows and doors in common areas. In view of the recent increases in the gas prices, the internal building's temperature is maintained below the thermal comfort. The presented variants include the proposal to leave the internal temperature at the present level, as well as to increase it to 20 °C. Heat transfer coefficients were calculated based on of the PN-EN 6946 standard and the heat demand for the buildings was estimated in the standard reference year in accordance with the PN-EN ISO 13790 standard. Results are compared with real values. The buildings’ models were prepared in the Audytor OZC 6.7. Pro software. The impact of appropriately sized photovoltaic system for each of the objects was also analyzed and the solar irradiation data has been taken from the RETScreen 4 software.


2013 ◽  
Vol 20 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Algirdas Kuprys ◽  
Ramūnas Gatautis

The renovation of multi-storey residential buildings reduces heat consumption intensity and decreases heat demand, which may have a harmful effect on a district heating supply system. The paper analyses the heat loss change in four district heating distribution networks (DHNs) of Kaunas at the various scenarios of buildings and DHN renovation stages. A bundle of genetic algorithm software package was used to carry out the districts’ distribution network hydraulic calculations in the case of building renovation without changing the hydrodynamic and network routes. The experimental data were used to calculate heat loss for old and new pipes. The computer data of networks used to summarise the cost of DHN then for the renovation of buildings as well as for renovation progress will go evenly with DHN refurbishment. Network optimization results were summarised by functional dependence. The comparison of the projects’ efficiency was analysed in the following cases: the diameters of pipes of DHN were not changed, new diameters of pipes were integrated partly after partial residential buildings renovation and after a complete renovation of residential building and optimisation of pipeline diameters. The efficiency of separate guidelines of the DHN refurbishment project was summarised by performing sensitivity analysis.


Author(s):  
Avi Friedman

<p>Green roofs are the integration of plant material and its supporting structures in buildings. Such an approach provides a habitat for local flora and fauna, helps manage storm water, reduces heat demand in winter and the cooling load in the summer, enhances the aesthetic values of dwellings, provides the occupants with comfort and amenities and strengthens environmental responsibility. Because roofs represent approximately 40 percent to 50 percent of the surfaces in urban areas, green roofs have an important role in drainage and as a result water management as well. In fact, when a green roof is installed on 50 percent or more of the roof’s surface, it guarantees 2 points and can contribute 7 additional points toward LEED certification - almost 20 percent of the required rating. This paper classifies green roofs and offers strategies for their integration in residential buildings and examines their benefits, construction principles and applications.</p>


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8047
Author(s):  
Łukasz Amanowicz

Due to the energy transformation in buildings, the proportions of energy consumption for heating, ventilation and domestic hot water preparation (DHW) have changed. The latter component can now play a significant role, not only in the context of the annual heat demand, but also in the context of selecting the peak power of the heat source. In this paper, the comparison of chosen methods for its calculation is presented. The results show that for contemporary residential buildings, the peak power for DHW preparation can achieve the same or higher value as the peak power for heating and ventilation. For this reason, nowadays the correct selection of the peak power of a heat source for DHW purposes becomes more important, especially if it uses renewable energy sources, because it affects its size and so the investment cost and economic efficiency. It is also indicated that in modern buildings, mainly accumulative systems with hot water storage tanks should be taken into account because they are less sensitive to design errors (wrongly selected peak value in the context of the uncertainty of hot water consumption) and because they result in acceptable value of peak power for DHW in comparison to heating and ventilation.


2014 ◽  
Vol 899 ◽  
pp. 16-23
Author(s):  
Tamás Csoknyai

The residential buildings built with prefabricated technology (also called panel buildings) represent a significant part of the building stock, particularly in Eastern Europe. These buildings are typically 30-40 years old and due to their poor energy performance they have been in the focus of energy policy makers over the recent years. These buildings are typically connected to district heating systems and the continuously decreasing heat demand caused by the renovation subsidy programs resulting in risks of inefficient operation and on the long term it questions the viability of the district heating systems. Therefore it is particularly important to have a clear picture on the energy consumption trends about this segment of the building stock. In this paper, the building stock of the city of Debrecen connected to district heating is analysed. The current energy consumption figures of the buildings are analysed. In Debrecen, the share of retrofitted buildings is relatively low (appr. 15%), therefore a future trend analysis was also carried out. The results of this study can be interesting for other cities as well, particularly those with a significant share of “panel buildings”.


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