scholarly journals Influence of Thermal Retrofitting on Annual Energy Demand for Heating in Multi-Family Buildings

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4625 ◽  
Author(s):  
Anna Życzyńska ◽  
Zbigniew Suchorab ◽  
Dariusz Majerek

The paper presented the analysis of heat consumption for heating in multi-family residential buildings before and after thermal retrofitting. The analysis involved four groups of buildings, i.e., 43 buildings in total, located in various localities, belonging to one weather station. The predicted level of energy savings resulting from thermal retrofitting was achieved from the energy audits. The actual heat consumption, following the calculation into so-called external standard conditions, was obtained based on the readouts from heat-meters. For each building, the values of heat consumption over the periods of 6–10 years were read. The performance measurements involved the periods before, during, and after thermal retrofitting. The following statistical tests were used for data analysis: Wilcoxon–Mann–Whitney, Shapiro–Wilk, Bartlett, ANOVA, Kruskal–Wallis, Dunn and Holm post-hoc. The performed analyses showed that the mean value of energy savings predicted by audits reached 38.5% when the real mean value of savings, achieved from heat-meters, equaled 30.3%. The annual energy demand factors for heating were calculated for final energy and non-renewable primary energy factors. It was established that most of the analyzed objects fulfilled the primary energy factor requirements found in the Polish technical and construction regulations, which were valid at the time of investment.

Author(s):  
Michael Keltsch ◽  
Werner Lang ◽  
Thomas Auer

The Energy Performance of Buildings Directive 2010 calls for the Nearly Zero Energy Standard for new buildings from 2021 onwards: Buildings using “almost no energy” are powered by renewable sources or energy produced by the building itself. For residential buildings, this ambitious new standard has already been reached. But for other building types this goal is still far away. The potential of these buildings to meet a Nearly Zero Energy Standard was investigated by analyzing ten case studies representing non-residential buildings with different uses. The analysis shows that the primary characteristics common to critical building types are a dense building context with a very high degree of technical installation (such as hospital, research and laboratory buildings). The large primary energy demand of these types of buildings cannot be compensated by building and property-related energy generation including off-site renewables. If the future Nearly Zero Energy Standard were to be defined with lower requirements because of this, the state related properties of Bavaria suggest that the real potential energy savings available in at least 85% of all new buildings would be insufficiently exploited. Therefore, it would be useful to instead individualize the legal energy verification process for new buildings to distinguish critical building types such as laboratories and hospitals.


Author(s):  
Michael Keltsch ◽  
Werner Lang ◽  
Thomas Auer

The Energy Performance of Buildings Directive 2010 calls for the Nearly Zero Energy Standard for new buildings from 2021 onwards: Buildings using “almost no energy” are powered by renewable sources or energy produced by the building itself. For residential buildings, this ambitious new standard has already been reached. But for other building types this goal is still far away. The potential of these buildings to meet a Nearly Zero Energy Standard was investigated by analyzing ten case studies representing non-residential buildings with different uses. The analysis shows that the primary characteristics common to critical building types are a dense building context with a very high degree of technical installation (such as hospital, research and laboratory buildings). The large primary energy demand of these types of buildings cannot be compensated by building and property-related energy generation including off-site renewables. If the future Nearly Zero Energy Standard were to be defined with lower requirements because of this, the state related properties of Bavaria suggest that the real potential energy savings available in at least 85% of all new buildings would be insufficiently exploited. Therefore, it would be useful to instead individualize the legal energy verification process for new buildings to distinguish critical building types such as laboratories and hospitals.


Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 119 ◽  
Author(s):  
Alessia Arteconi ◽  
Luca Del Zotto ◽  
Roberto Tascioni ◽  
Khamid Mahkamov ◽  
Chris Underwood ◽  
...  

In this paper, the smart management of buildings energy use by means of an innovative renewable micro-cogeneration system is investigated. The system consists of a concentrated linear Fresnel reflectors solar field coupled with a phase change material thermal energy storage tank and a 2 kWe/18 kWth organic Rankine cycle (ORC) system. The microsolar ORC was designed to supply both electricity and thermal energy demand to residential dwellings to reduce their primary energy use. In this analysis, the achievable energy and operational cost savings through the proposed plant with respect to traditional technologies (i.e., condensing boilers and electricity grid) were assessed by means of simulations. The influence of the climate and latitude of the installation was taken into account to assess the performance and the potential of such system across Europe and specifically in Spain, Italy, France, Germany, U.K., and Sweden. Results show that the proposed plant can satisfy about 80% of the overall energy demand of a 100 m2 dwelling in southern Europe, while the energy demand coverage drops to 34% in the worst scenario in northern Europe. The corresponding operational cost savings amount to 87% for a dwelling in the south and at 33% for one in the north.


Author(s):  
Jerzy Sowa ◽  
Maciej Mijakowski

A humidity-sensitive demand-controlled ventilation system is known for many years. It has been developed and commonly applied in regions with an oceanic climate. Some attempts were made to introduce this solution in Poland in a much severe continental climate. The article evaluates this system's performance and energy consumption applied in an 8-floor multi-unit residential building, virtual reference building described by the National Energy Conservation Agency NAPE, Poland. The simulations using the computer program CONTAM were performed for the whole hating season for Warsaw's climate. Besides passive stack ventilation that worked as a reference, two versions of humidity-sensitive demand-controlled ventilation were checked. The difference between them lies in applying the additional roof fans that convert the system to hybrid. The study confirmed that the application of demand-controlled ventilation in multi-unit residential buildings in a continental climate with warm summer (Dfb) leads to significant energy savings. However, the efforts to ensure acceptable indoor air quality require hybrid ventilation, which reduces the energy benefits. It is especially visible when primary energy use is analyzed.


Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 362
Author(s):  
Tomasz Szul

Energy consumption for heating of single-family residential buildings is a basic item in energy balance and significantly affects their operating costs. Accuracy of heat consumption assessment in existing buildings to a large extent determines the decision on taking actions aimed at heat consumption rationalization, both at the level of a single building and at regional or national level. In the case of energy calculations for the existing buildings, a problem often arises in the form of lack of complete architectural and construction documentation of the analyzed objects. Therefore, there is a need to search for methods that will be suitable for rapid energy analysis in existing buildings. These methods should give satisfactory results in predicting energy consumption when there is limited access to data characterizing the building. Therefore, the aim of this study was to check the usefulness of a model based on thermal characteristics for estimating energy consumption for heating in single-family residential buildings. The research was conducted on a group of 84 buildings, for which the energy characteristics were determined based on the actual energy consumption. In addition, information was collected on variables describing these buildings in terms of construction technology and building geometry, from which the following were extracted for further calculations: cubic capacity, heated area, and year of construction. This made it possible to build a prediction model, which enables the application of a fast, relatively simple procedure of estimating the final energy demand index for heating buildings. The resulting calculations were compared with actual values (calculated from energy bills) and then evaluated according to the standards for evaluating model quality proposed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). In this way, it was possible to determine whether, in the absence of building documents, the indicative method gives good results when estimating the energy demand for heating single-family residential buildings.


Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6669
Author(s):  
Jerzy Sowa ◽  
Maciej Mijakowski

Humidity-sensitive, demand-controlled ventilation systems have been in use for many years in regions with oceanic climates. Some attempts have been made to apply this technology in Poland, which has a continental climate. This article evaluates the performance and energy consumption of such a system when applied in an eight-floor, multiunit, residential building, i.e., the virtual reference building described by the National Energy Conservation Agency (NAPE), Poland. Simulations using the computer program CONTAM were performed for the whole heating season based upon the climate in Warsaw. Besides passive stack ventilation, that served as a reference, two ventilation systems were studied: one standard and one “hybrid” system with additional roof fans. This study confirmed that the application of humidity-sensitive, demand-controlled ventilation in multiunit residential buildings in a continental climate (Dfb) led to significant energy savings (up to 11.64 kWh/m2 of primary energy). However, the operation of the system on higher floors was found to be ineffective. Ensuring consistent operation of the system on all floors required supplementary fans. The introduction of a hybrid mode reduced carbon dioxide concentrations by approximately 32% in the units located in the upper part of the building. The energetic effect in such cases depends strongly on the electricity source. In the case of the national energy grid, savings of primary energy would be relatively low, i.e., 1.07 kWh/m2, but in the case of locally produced renewable energy, the energy savings would be equal to 5.18 kWh/m2.


Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4099 ◽  
Author(s):  
Rokas Tamašauskas ◽  
Jolanta Šadauskienė ◽  
Dorota Anna Krawczyk ◽  
Violeta Medelienė

Following a new climate and energy plan, the European Union (EU) gives big attention to energy savings. The overall assessment of energy saving measures is very important. Thus, it is crucial to estimate in a proper way the primary energy factor, which is used in calculations of primary energy consumption from renewable energy (RE) sources in a Nearly Zero Energy Building (NZEB). The conduced studies of the literature and national regulations showed that different methods to determine energy from photovoltaic (PV) systems are used. The aim of this paper is to evaluate the primary energy factors of energy from photovoltaics and determine the average value. To achieve this aim, the data of 30 photovoltaic systems from Lithuania were analyzed. The results show a 35% diversification in the values of non-renewable primary energy factor, depending on the PV systems’ capacities, with the average on a level of 1.038.


2018 ◽  
Vol 44 ◽  
pp. 00069 ◽  
Author(s):  
Maciej Knapik

The article presents the problem of thermo-modernization and the reduction of energy demand for heating purposes in existing residential buildings. The thermo-modernization process has to adapt the existing building to the standard of a building with low energy demand and applicable regulations. Low-energy constructions are a result of introduction of new solutions in building design process. Their main objective is to achieve a significant reduction in demand for renewable primary energy, necessary to cover the needs of these buildings, mostly related to their heating, ventilation and domestic hot water. The article presents the results of the analysis and calculation of selected thermo-modernization variants. The results showed that thermo-modernization process of existing residential buildings is justified both energetically and economically.


Author(s):  
Benkechkache Imane

Energy is one of the common determinant factors related to social, environmental and economic problems, which can also contribute to their solution. Among sectors where studies could be done to reduce energy demand, is building. This latter is the largest primary energy consumer and responsible for more than 40% of total CO2 emissions. Therefore, improving energy efficiency in buildings represents an economic and ecological challenge. The built environment quality, with good insulation and high-performance building materials, constitutes the first step towards this aim. Yet, this is not enough to make buildings low energy consumption. But then again, a starting point for which, it is necessary to manage how it should be occupied and exploited. Improving energy efficiency of buildings involves several steps through which, coherent actions, will enable energy savings acting on different human and material parameters. The conceptual approach for improving energy efficiency is identical for residential and tertiary sectors. However, in practice this is different due to divergences related to: technical aspects; used tools; operating and maintenance costs and return time of investment. The purpose of this research is to investigate an example of Energy Enhancement housing in Tafilelt ksar in the M’zab valley in Algeria (an example of ecologic planning with modern habitat perfectly adapted to environment), with the objective of creating adaptable housing according to changing needs of future generations.


2014 ◽  
Vol 6 (4) ◽  
pp. 414-420 ◽  
Author(s):  
Giedrė Streckienė ◽  
Elena Polonis

To meet the goals established by Directive 2010/31/EU of the European Parliament and of the Council on the energy performance of buildings, the topics of energy efficiency in new and old buildings must be solved. Research and development of new energy solutions and technology are necessary for increasing energy performance of buildings. Three low-energy multi-dwelling buildings have been modelled and analyzed in the presented study. All multi-dwelling houses are made of similar single-family house cells. However, multi-dwelling buildings are of different geometry, flat number and height. DesignBuilder software was used for simulating and determining heating, cooling and electricity demand for buildings. Three different materials (silicate, ceramic and clay concrete blocks) as bearing constructions of external walls have been analyzed. To decrease cooling demand for buildings, the possibility of mounting internal or external louvers has been considered. Primary energy savings for multi-dwelling buildings using passive solar measures have been determined. Norint pasiekti Europos Sąjungos direktyvos 2010/31/EB tikslus dėl pastatų energinio naudingumo, reikia spręsti energijos efektyvumo klausimus naujų ir esamų pastatų srityje. Naujų energinių sprendinių ir technologijų tyrimai bei plėtra būtini norint padidinti pastatų energinį naudingumą. Šiame tyrime modeliuojami ir analizuojami trys mažaenergiai daugiabučiai pastatai. Visi jie sudaryti iš vienodo dydžio butų, tačiau pastatai tarpusavyje skiriasi geometrija, butų skaičiumi ir aukštingumu. Siekiant nustatyti ir išnagrinėti pastatų šilumos, vėsos ir elektros energijos poreikius, naudotasi DesignBuilder programa. Visų daugiabučių pastatų atvejais nagrinėjamos trys skirtingos išorės sienų laikančiųjų konstrukcijų medžiagos: silikatiniai, keraminiai ir keramzitbetonio blokeliai. Siekiant sumažinti vėsos poreikį pastatuose taip pat buvo analizuojama galimybė sumontuoti vidines arba išorines žaliuzes. Nustatyti sutaupytieji pirminės energijos kiekiai daugiabučių pastatų atvejams taikant pasyviąsias apsaugos nuo saulės priemones.


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