scholarly journals Estimation of the Heat Loss Coefficient of Two Occupied Residential Buildings through an Average Method

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5724 ◽  
Author(s):  
Irati Uriarte ◽  
Aitor Erkoreka ◽  
Pablo Eguia ◽  
Enrique Granada ◽  
Koldo Martin-Escudero

The existing performance gap between the design and the real energy consumption of a building could have three main origins: the occupants’ behaviour, the performance of the energy systems and the performance of the building envelope. Through the estimation of the in-use Heat Loss Coefficient (HLC), it is possible to characterise the building’s envelope energy performance under occupied conditions. In this research, the estimation of the HLC of two individual residential buildings located in Gainsborough and Loughborough (UK) was carried out using an average method. This average method was developed and successfully tested in previous research for an occupied four-story office building with very different characteristics to individual residential buildings. Furthermore, one of the analysed residential buildings is a new, well-insulated building, while the other represents the old, poorly insulated semidetached residential building typology. Thus, the monitored data provided were filtered in order to apply the abovementioned average method. Even without fulfilling all the average method requirements for these two residential buildings, the method provides reliable HLC values for both residential buildings. For the house in Gainsborough, the best estimated HLC value was 60.2 W/K, while the best approach for Loughborough was 366.6 W/K. Thus, despite the uncertainty sources found during the analysis, the method seems promising for its application to residential buildings.

2021 ◽  
Vol 899 (1) ◽  
pp. 012009
Author(s):  
A C Karanafti ◽  
T G Theodosiou

Abstract Improving the energy efficiency of residential buildings is of outmost importance for reducing their environmental footprint. Recent studies demonstrate that a highly insulated building envelope may burden the building’s performance during the cooling period, especially in regions with hot summers. In this study, the energy performance of a residential building in different Mediterranean regions (Jordan, Greece, Iraq, Egypt, Syria, Morocco, Cyprus, Saudi Arabia, Libya, and Spain) is investigated. Two thermal transmittance values are applied to the building shell, a scenario with a very low one and a scenario with a higher one, to examine under which conditions the cooling performance is improved. A dynamic insulation configuration is also implemented, and its operation is studied for the cooling period of each city. It is concluded that in Southern European and Northern African regions building envelopes with lower thermal resistances perform better, while in even Southern regions an increased thermal resistance may prevent the heat from entering the building more effectively. With the switching insulation system, a great reduction in the cooling demands was reported, which reached up to 50% in Spain, and it was shown that in the southern regions the configuration’s operation should be customized to the ambient conditions to optimize its performance.


Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 405
Author(s):  
Amy Huynh ◽  
Regina Dias Barkokebas ◽  
Mohamed Al-Hussein ◽  
Carlos Cruz-Noguez ◽  
Yuxiang Chen

Due to the energy and environmental impacts attributed to the operational phase of the building sector, efforts have been made to improve building energy performance through the implementation of restrictive energy requirements by regulatory bodies. In this context, the primary objective of this paper is to investigate and compare regulations that govern the building envelope energy performance of new residential buildings in cold-climate regions, primarily in Canada, Finland, Iceland, Norway, Sweden, China, and Russia. The aim is to identify similarities and dissimilarities among the energy regulations of these countries, as well as potentials for development of more effective building codes. This study verifies that the investigated energy requirements diverge considerably—for instance, the required thermal resistance per unit area of above-grade exterior walls in Sweden is almost two times that of a similar climate zone in Canada. Based on the comparisons and case analyses, recommendations for energy requirements pertinent to building envelope of new residential buildings in cold-climate regions are proposed.


2020 ◽  
Vol 10 (13) ◽  
pp. 4489
Author(s):  
Zakaria Che Muda ◽  
Payam Shafigh ◽  
Norhayati Binti Mahyuddin ◽  
Samad M.E. Sepasgozar ◽  
Salmia Beddu ◽  
...  

The increasing need for eco-friendly green building and creative passive design technology in response to climatic change and global warming issues will continue. However, the need to preserve and sustain the natural environment is also crucial. A building envelope plays a pivotal role in areas where the greatest heat and energy loss often occur. Investment for the passive design aspect of building envelopes is essential to address CO 2 emission. This research aims to explore the suitability of using integral-monolithic structural insulation fibre-reinforced lightweight aggregate concrete (LWAC) without additional insulation as a building envelope material in a high-rise residential building in the different climatic zones of the world. Polypropylene and steel fibres in different dosages were used in a structural grade expanded clay lightweight aggregate concrete. Physical and thermal properties of fibre reinforced structural LWAC, normal weight concrete (NWC) and bricks were measured in the lab. The Autodesk@Revit-GBS simulation program was implemented to simulate the energy consumption of a 29-storey residential building with shear wall structural system using the proposed fibre-reinforced LWAC materials. Results showed that energy savings between 3.2% and 14.8% were incurred in buildings using the fibre-reinforced LWAC across various climatic regions as compared with traditional NWC and sand-cement brick and clay brick walls. In conclusion, fibre-reinforced LWAC in hot-humid tropical and temperate Mediterranean climates meet the certified Green Building Index (GBI) requirements of less than 150 kW∙h∙m−2. However, in extreme climatic conditions of sub-arctic and hot semi-arid desert climates, a thicker wall or additional insulation is required to meet the certified green building requirements. Hence, the energy-saving measure is influenced largely by the use of fibre-reinforced LWAC as a building envelope material rather than because of building orientation.


2019 ◽  
Vol 111 ◽  
pp. 03035 ◽  
Author(s):  
Raimo Simson ◽  
Endrik Arumägi ◽  
Kalle Kuusk ◽  
Jarek Kurnitski

In the member states of the European Union (EU), nearly-Zero Energy Buildings (nZEB) are becoming mandatory building practice in 2021. It is stated, that nZEB should be cost-optimal and the energy performance levels should be re-defined after every five years. We conducted cost-optimality analyses for two detached houses, one terraced house and one apartment building in Estonia. The analysis consisted on actual construction cost data collection based on bids of variable solutions for building envelope, air tightness, windows, heat supply systems and local renewable energy production options. For energy performance analysis we used dynamic simulation software IDA-ICE. To assess cost-effectiveness, we used Net Present Value (NPV) calculations with the assessment period of 30 years. The results for cost-optimal energy performance level for detached house with heated space of ~100 m2 was 79 kWh/(m2 a), for the larger house (~200 m2) 87 kWh/(m2 a), for terraced house with heated space of ~600 m2 71 kWh/(m2 a) and for the apartment building 103 kWh/(m2 a) of primary energy including all energy use with domestic appliances. Thus, the decrease in cost-optimal level in a five-year period was ~60% for the detached house and ~40% for the apartment building, corresponding to a shift in two EPC classes.


2019 ◽  
Vol 14 (2) ◽  
pp. 109-136
Author(s):  
Chaitali Basu ◽  
Virendra Kumar Paul ◽  
M.G. Matt Syal

The energy performance of an existing building is the amount of energy consumed to meet various needs associated with the standardized use of a building and is reflected in one or more indicators known as Building Energy Performance Indicators (EnPIs). These indicators are distributed amongst six main factors influencing energy consumption: climate, building envelope, building services and energy systems, building operation and maintenance, occupants' activities and behaviour, and indoor environmental quality. Any improvement made to either the existing structure or the physical and operational upgrade of a building system that enhances energy performance is considered an energy efficiency retrofit. The main goal of this research is to support the implementation of multifamily residential building energy retrofits through expert knowledge consensus on EnPIs for energy efficiency retrofit planning. The research methodology consists of a comprehensive literature review which has identified 35 EnPIs for assessing performance of existing residential buildings, followed by a ranking questionnaire survey of experts in the built-environment to arrive at a priority listing of indicators based on mean rank. This was followed by concordance analysis and measure of standard deviation. A total of 280 experts were contacted globally for the survey, and 106 completed responses were received resulting in a 37.85% response rate. The respondents were divided into two groups for analysis: academician/researchers and industry practitioners. The primary outcome of the research is a priority listing of EnPIs based on the quantitative data from the knowledge-base of experts from these two groups. It is the outcome of their perceptions of retrofitting factors and corresponding indicators. A retrofit strategy consists of five phases for retrofitting planning in which the second phase comprises an energy audit and performance assessment and diagnostics. This research substantiates the performance assessment process through the identification of EnPIs.


Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 237 ◽  
Author(s):  
S. Soutullo ◽  
E. Giancola ◽  
M. J. Jiménez ◽  
J. A. Ferrer ◽  
M. N. Sánchez

Based on the European energy directives, the building sector has to provide comfortable levels for occupants with minimum energy consumption as well as to reduce greenhouse gas emissions. This paper aims to compare the impact of climate change on the energy performance of residential buildings in order to derive potential design strategies. Different climate file inputs of Madrid have been used to quantify comparatively the thermal needs of two reference residential buildings located in this city. One of them represents buildings older than 40 years built according to the applicable Spanish regulations prior to 1979. The other refers to buildings erected in the last decade under more energy-restrictive constructive regulations. Three different climate databases of Madrid have been used to assess the impact of the evolution of the climate in recent years on the thermal demands of these two reference buildings. Two of them are typical meteorological years (TMY) derived from weather data measured before 2000. On the contrary, the third one is an experimental file representing the average values of the meteorological variables registered in Madrid during the last decade. Annual and monthly comparisons are done between the three climate databases assessing the climate changes. Compared to the TMYs databases, the experimental one records an average air temperature of 1.8 °C higher and an average value of relative humidity that is 9% lower.


2019 ◽  
Vol 11 (21) ◽  
pp. 6085 ◽  
Author(s):  
David Pálenský ◽  
Antonín Lupíšek

This paper deals with the problem that actual building regulations do not reflect the climate targets set by the Paris Agreement. To address this, a benchmark was developed for greenhouse gas (GHG) emissions of buildings on the basis of the Emissions Gap Report. We first applied an equal allocation of the GHG emission limit for 2030 among the forecasted population to calculate a virtual personal GHG emission limit. We took a proportion of this personal limit for the purpose of housing and extrapolated it for the whole building based on the number of occupants. We also undertook a case study of an actual multifamily residential building and compared its standard design to the benchmark using a simplified life cycle assessment (LCA) method in line with the national SBToolCZ method. The results showed that the assessed residential house exceeded the emission requirement by a factor of 2.5. Based on the assessment, six sets of saving measures were proposed to reduce the operational and embodied GHG emissions. The saving measures included change in temperature zoning, improvement of the U-values of the building envelope, exchange of construction materials for reduced embodied GHG emissions, exchange of heat source for biomass boiler, introduction of light-emitting diode (LED) lighting, use of mechanical ventilation with heat recovery, addition of vacuum solar collectors, and the addition of photovoltaic (PV) panels. Finally, the variants were compared and their suitability in the Czech conditions was examined.


Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2469
Author(s):  
Evi Lambie ◽  
Dirk Saelens

Since households are one of the most energy-intensive sectors in Europe, retrofit of dwellings is promoted to increase energy efficiency. Recent research, however, shows that the energy performance after retrofit does not always meet the target values, which can be caused by amongst other things, a deviating building envelope performance. This paper compares the theoretical and measured building envelope performance for a real-life case study in post-retrofit state, in order to illustrate the limitations of calculation methods and characterization models. First, the performance is evaluated on building scale by verifying the correspondence between the default theoretical heat loss coefficient (HLC) and the measured HLC, which was determined by following the guidelines formulated within IEA EBC Annex 58 and Annex 71. In order to illustrate the limitations of the standard calculation method in real-life conditions, the theoretical variability of the HLC is evaluated, generated by variating infiltration heat losses and heat exchange with neighboring dwellings. Second, the performance is investigated on a component scale by assessing the theoretical and measured thermal resistances, identified from heat flux tests. Additionally, nonhomogeneous assembled components and air leaks are simulated to verify probable causes for the locally varying measured values and to illustrate the limitations of calculations and characterization methods. The results illustrate the limitations of the calculation methods by the assessment of the strong variability of the theoretical HLC, depending on assumptions regarding infiltration and heat exchange with neighboring dwellings. In addition, component simulations indicated that deficiencies on a component scale could be caused by a nonhomogeneous assembly and air cavity flows of the component. Moreover, a detailed assessment of an unreliable thermal resistance illustrates the limitations of the used characterization method. Finally, a contrast was found between the quite good performance on building scale (15% deviation between the theoretical and measured HLC) and poor performance on a component scale (only one out of nine monitored components met their theoretical target values), which illustrates the complexity of the building envelope performance.


2013 ◽  
Vol 361-363 ◽  
pp. 235-238
Author(s):  
Chen Lin ◽  
Qiu Xia Wang ◽  
Xiao Tong Peng

The steel residential building has been widely used for its good seismic performances. In order to study the energy-saving behavior of the existing steel residential building, an on-site test on envelope structure of a typical steel building in cold region is conducted. Based on that, a simplified numerical model is established in which dynamic energy theories, solar radiations and indoor thermal disturbances are considered. The model is verified through testing data. Parameter analyses including 6 series sum up to 38 models are carried out on 6 main influential factors. The results show that improving thermal behavior of building envelope, adopting flexible sunshade schemes in different seasons, using even and simple building configuration and adopting different window-wall ratios for windows with different orientation are effective ways to decrease the energy consumption of buildings. The thermal design recommendations for steel residential buildings are also produced.


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