scholarly journals Understanding the energy performance GAP: case studies of energy efficient homes

2021 ◽  
Author(s):  
Moe Otsubo
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Energy Performance ◽  
Initial Energy ◽  
Energy Simulation ◽  
Design Stage ◽  
Performance Gap ◽  
Energy Models ◽  
Dynamic Energy Simulation ◽  
Actual Energy Consumption

The energy performance gap between the predicted and actual energy consumption of 3 LEED for Homes certified buildings were investigated. The actual energy consumptions of the homes were found to be 23 to 77% higher than the initial energy consumption predictions made during the design stage. Revisions to the HOT2000 models to account for changes made between the design and occupancy phase of the buildings helped reduce the gap (9 to 40%). The sources of the discrepancies were found to be related to the energy modeling program’s limitations, inconsistency between the energy model and the actual building, and additional loads in the homes. The HOT2000 program, which is used for obtaining the EnerGuide rating for LEED certified homes, was compared against a dynamic energy simulation program to assess the applicability of the use of the former for energy efficient homes. The use of EnergyPlus not only allowed for a more accurate representation of the actual homes in the energy models, but an increase in the EnerGuide rating for the home was seen, which in turn equates to additional points for the home under the “Energy & Atmosphere” category for the LEED for Homes certification process

scholarly journals Understanding the energy performance GAP: case studies of energy efficient homes

2021 ◽  
Author(s):  
Moe Otsubo
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Energy Performance ◽  
Initial Energy ◽  
Energy Simulation ◽  
Design Stage ◽  
Performance Gap ◽  
Energy Models ◽  
Dynamic Energy Simulation ◽  
Actual Energy Consumption

The energy performance gap between the predicted and actual energy consumption of 3 LEED for Homes certified buildings were investigated. The actual energy consumptions of the homes were found to be 23 to 77% higher than the initial energy consumption predictions made during the design stage. Revisions to the HOT2000 models to account for changes made between the design and occupancy phase of the buildings helped reduce the gap (9 to 40%). The sources of the discrepancies were found to be related to the energy modeling program’s limitations, inconsistency between the energy model and the actual building, and additional loads in the homes. The HOT2000 program, which is used for obtaining the EnerGuide rating for LEED certified homes, was compared against a dynamic energy simulation program to assess the applicability of the use of the former for energy efficient homes. The use of EnergyPlus not only allowed for a more accurate representation of the actual homes in the energy models, but an increase in the EnerGuide rating for the home was seen, which in turn equates to additional points for the home under the “Energy & Atmosphere” category for the LEED for Homes certification process

scholarly journals ANALYSING THE GAP BETWEEN PREDICTED AND ACTUAL OPERATIONAL ENERGY CONSUMPTION IN BUILDINGS: A REVIEW

2021 ◽  
Author(s):  
M. Rajithan ◽  
◽  
D. Soorige ◽  
S.D.I.A. Amarasinghe ◽  
◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Building Design ◽  
Energy Performance ◽  
Vital Role ◽  
Energy Simulation ◽  
Design Stage ◽  
Performance Gap ◽  
Operational Energy ◽  
Significant Performance

Operational energy consumption in buildings has a crucial impact on global energy consumption. Nevertheless, significant energy savings can be achieved in buildings if properly designed, constructed, and operated. Building Energy Simulation (BES) plays a vital role in the design and optimisation of buildings. BES is used to compare the cost-effectiveness of energy-conservation measures in the design stage and assess various performance optimisation measures during the operational phase. However, there is a significant ‘performance gap’ between the predicted and the actual energy performance of buildings. This gap has reduced the trust and application of the BES. This article focused on investigating BES, reasons that lead to a performance gap between predicted and actual operational energy consumption of buildings, and the ways of minimising the gap. The article employed a comprehensive literature review as the research methodology. Findings revealed that reasons such as limited understanding of the building design, the complexity of the building design, poor commissioning, occupants’ behaviour, etc., influence the energy performance gap. After that, the strategies have been identified to minimise the energy performance gap such as proper commissioning, creating general models to observe occupants’ behaviour in buildings, and using the general models for energy simulation, ensuring better construction and quality through training and education, etc. Further, the findings of this study could be implemented by practitioners in the construction industry to effectively use energy simulation applications in designing energy-efficient and sustainable buildings.

scholarly journals Building Energy Performance Certificate—A Relevant Indicator of Actual Energy Consumption and Savings?

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3455
Author(s):  
Aleksandar S. Anđelković ◽  
Miroslav Kljajić ◽  
Dušan Macura ◽  
Vladimir Munćan ◽  
Igor Mujan ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Gap ◽  
Building Energy ◽  
Energy Performance ◽  
Building Stock ◽  
District Heating System ◽  
Performance Gap ◽  
Building Energy Performance ◽  
Actual Energy Consumption

A building energy performance gap can be illustrated as the difference between the theoretical (methodologically defined) and the actual energy consumption. In EU countries, Energy Performance Certificates are issued when buildings are constructed, sold, or leased. This information is the first step in order to evaluate the energy performance of the building stock. In Serbia, when issuing an energy certificate, the adopted national methodology recognizes only energy consumption for heating. The main purpose of this paper is to evaluate the energy gap and estimate the relevance of an Energy Performance Certificate to meet the national energy efficiency or carbon target. An Energy Performance Certificate determines the theoretical residential and commercial building energy efficiency or its “design intent”. This research stresses the necessity of measuring and achieving reductions in actual energy consumption through system regulation and consumers’ self-awareness in buildings. The research compares the performance of the building stock (135) that is connected to the District Heating System (DHS), with its own integrated heat meter, to Individual Gas Boiler (IGB) systems (18), in the city of Novi Sad, Serbia, built after 2014. For the purpose of comparing energy consumption, 16 buildings were selected that are very similar in terms of design, operation, and location. The data used are derived from metered consumption data, official evidence of city service companies, and Energy Performance Certificates of the considered buildings. We have determined that IGB systems have a much wider specific annual performance gap (11.19–101 kWh/m2a) than the buildings in the DHS (3.16–18.58 kWh/m2a).

Architecture as a strategy for reduced energy consumption? An in-depth analysis of residential practices’ influence on the energy performance of passive houses

2014 ◽  
Vol 3 (3) ◽  
pp. 192-206 ◽  
Author(s):  
Solvår Wågø ◽  
Thomas Berker
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Energy Savings ◽  
Energy Performance ◽  
Content Type ◽  
Depth Analysis ◽  
New Energy ◽  
Passive Houses ◽  
The One ◽  
Actual Energy Consumption

Purpose – The purpose of this paper is to discuss how architectural solutions may influence residential practice and energy consumption. Design/methodology/approach – The paper is part of a larger study based on qualitative investigations of six energy-efficient housing projects in Norway. Here, the authors examine one of these projects, Løvåshagen in Bergen, the first Norwegian passive house flat building. Based on a combination of 14 interviews with household members and energy consumption data for all flats, the authors show how residential practices influence energy consumption. In the discussion and conclusion, the authors focus on the role of the architecture in these practices. Findings – On the one hand, Løvåshagen reflects a mainstreaming approach to sustainable building, attracting a wide array of different occupants. On the other hand, the specific add-ons that are intended to make the buildings energy efficient require new definitions of comfort and new skills to achieve the promised energy savings. This combination can explain why Løvåshagen, after four years of occupation, has a large variation in actual energy consumption. Practical implications – In designing new energy-efficient housing, greater attention should be paid to the level of end-user control and adaptability, the level of system complexity, and the need for adequate information. An alternative to the mainstreaming approach would be to actively use architecture to influence residential practices towards reduced energy consumption. Originality/value – The use of qualitative methods to analyse quantitative energy data is original and provides promising opportunities to understand the significance of residential practices regarding actual energy consumption.

scholarly journals Managing energy performance in buildings from design to operation using modelling and calibration

2021 ◽  
pp. 014362442110083
Author(s):  
Nishesh Jain ◽  
Esfand Burman ◽  
Dejan Mumovic ◽  
Mike Davies
Keyword(s):  
Best Practice ◽  
Good Practice ◽  
Energy Performance ◽  
Operating Conditions ◽  
Design Stage ◽  
Performance Gap ◽  
Actual Performance ◽  
Simulation Tools ◽  
Calibration Protocol ◽  
Covering Design

To manage the concerns regarding the energy performance gap in buildings, a structured and longitudinal performance assessment of buildings, covering design through to operation, is necessary. Modelling can form an integral part of this process by ensuring that a good practice design stage modelling is followed by an ongoing evaluation of operational stage performance using a robust calibration protocol. In this paper, we demonstrate, via a case study of an office building, how a good practice design stage model can be fine-tuned for operational stage using a new framework that helps validate the causes for deviations of actual performance from design intents. This paper maps the modelling based process of tracking building performance from design to operation, identifying the various types of performance gaps. Further, during the operational stage, the framework provides a systematic way to separate the effect of (i) operating conditions that are driven by the building’s actual function and occupancy as compared with the design assumptions, and (ii) the effect of potential technical issues that cause underperformance. As the identification of issues is based on energy modelling, the process requires use of advanced and well-documented simulation tools. The paper concludes with providing an outline of the software platform requirements needed to generate robust design models and their calibration for operational performance assessments. Practical application The paper’s findings are a useful guide for building industry professionals to manage the performance gap with appropriate accuracy through a robust methodology in an easy to use workflow. The methodological framework to analyse building energy performance in-use links best practice design stage modelling guidance with a robust operational stage investigation. It helps designers, contractors, building managers and other stakeholders with an understanding of procedures to follow to undertake an effective measurement and verification exercise.

Recommended angle of a modular dynamic façade in hot-arid climate: daylighting and energy simulation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Seyedeh Samaneh Golzan ◽  
Mina Pouyanmehr ◽  
Hassan Sadeghi Naeini
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Energy Performance ◽  
Arid Climate ◽  
Visual Comfort ◽  
Building Envelopes ◽  
Content Type ◽  
Optimum Angle ◽  
Energy Efficient Buildings ◽  
Hot Arid Climate

PurposeThe modular dynamic façade (MDF) concept could be an approach in a comfort-centric design through proper integration with energy-efficient buildings. This study focuses on obtaining and/or calculating an efficient angle of the MDF, which would lead to the optimum performance in daylight availability and energy consumption in a single south-faced official space located in the hot-arid climate of Yazd, Iran.Design/methodology/approachThe methodology consists of three fundamental parts: (1) based on previous related studies, a diamond-based dynamic skin façade was applied to a south-faced office building in a hot-arid climate; (2) the daylighting and energy performance of the model were simulated annually; and (3) the data obtained from the simulation were compared to reach the optimum angle of the MDF.FindingsThe results showed that when the angle of the MDF openings was set at 30°, it could decrease energy consumption by 41.32% annually, while daylight simulation pointed that the space experienced the minimum possible glare at this angle. Therefore, the angle of 30° was established as the optimum angle, which could be the basis for future investment in responsive building envelopes.Originality/valueThis angular study simultaneously assesses the daylight availability, visual comfort and energy consumption on a MDF in a hot-arid climate.

scholarly journals Understanding the Reasons behind the Energy Performance Gap of an Energy-Efficient Building, through a Probabilistic Approach and On-Site Measurements

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6178
Author(s):  
Pierryves Padey ◽  
Kyriaki Goulouti ◽  
Guy Wagner ◽  
Blaise Périsset ◽  
Sébastien Lasvaux
Keyword(s):  
Energy Efficient ◽  
Probabilistic Approach ◽  
Energy Performance ◽  
High Energy ◽  
Performance Gap ◽  
Post Evaluation ◽  
Energy Efficient Buildings ◽  
Ex Post ◽  
The Difference ◽  
Energy Efficient Building

The performance gap, defined as the difference between the measured and the calculated performance of energy-efficient buildings, has long been identified as a major issue in the building domain. The present study aims to better understand the performance gap in high-energy performance buildings in Switzerland, in an ex-post evaluation. For an energy-efficient building, the measured heating demand, collected through a four-year measurement campaign was compared to the calculated one and the results showed that the latter underestimates the real heating demand by a factor of two. As a way to reduce the performance gap, a probabilistic framework was proposed so that the different uncertainties of the model could be considered. By comparing the mean of the probabilistic heating demand to the measured one, it was shown that the performance gap was between 20–30% for the examined period. Through a sensitivity analysis, the active air flow and the shading factor were identified as the most influential parameters on the uncertainty of the heating demand, meaning that their wrong adjustment, in reality, or in the simulations, would increase the performance gap.

scholarly journals The Performance Gap in Energy-Efficient Office Buildings: How the Occupants Can Help?

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1480 ◽  
Author(s):  
Qadeer Ali ◽  
Muhammad Jamaluddin Thaheem ◽  
Fahim Ullah ◽  
Samad M. E. Sepasgozar
Keyword(s):  
Energy Efficient ◽  
Behavioral Interventions ◽  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Office Buildings ◽  
Occupant Behavior ◽  
Energy Usage ◽  
Performance Gap ◽  
Energy Efficient Buildings

Rising demand and limited production of electricity are instrumental in spreading the awareness of cautious energy use, leading to the global demand for energy-efficient buildings. This compels the construction industry to smartly design and effectively construct these buildings to ensure energy performance as per design expectations. However, the research tells a different tale: energy-efficient buildings have performance issues. Among several reasons behind the energy performance gap, occupant behavior is critical. The occupant behavior is dynamic and changes over time under formal and informal influences, but the traditional energy simulation programs assume it as static throughout the occupancy. Effective behavioral interventions can lead to optimized energy use. To find out the energy-saving potential based on simulated modified behavior, this study gathers primary building and occupant data from three energy-efficient office buildings in major cities of Pakistan and categorizes the occupants into high, medium, and low energy consumers. Additionally, agent-based modeling simulates the change in occupant behavior under the direct and indirect interventions over a three-year period. Finally, energy savings are quantified to highlight a 25.4% potential over the simulation period. This is a unique attempt at quantifying the potential impact on energy usage due to behavior modification which will help facility managers to plan and execute necessary interventions and software experts to develop effective tools to model the dynamic usage behavior. This will also help policymakers in devising subtle but effective behavior training strategies to reduce energy usage. Such behavioral retrofitting comes at a much lower cost than the physical or technological retrofit options to achieve the same purpose and this study establishes the foundation for it.

Influence of building and indoor environmental parameters on designing energy-efficient buildings

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Stephen O. Eromobor ◽  
Dillip Kumar Das ◽  
Fidelis Emuze
Keyword(s):  
South Africa ◽  
Energy Consumption ◽  
Energy Efficient ◽  
Environmental Parameters ◽  
Energy Performance ◽  
Width Ratio ◽  
Content Type ◽  
Window Width ◽  
University Buildings ◽  
Building Parameters

PurposeArguments for the design of sustainable university buildings have emerged in South Africa. Energy being a major determinant of the sustainability of buildings, the purpose of this study was to examine the influence of various building and indoor environmental parameters on the energy performance of university buildings in South Africa.Design/methodology/approachA quantitative survey research method, administered within the context of university buildings in South Africa, was used. Data about 16 buildings from three universities were collected. Relevant, inferential statistical analyses were conducted to examine the relative influence of the building parameters on the energy consumed in the buildings. Also, regression models within building parameters were developed independently and in a combination that could be used to estimate energy consumption in the university buildings.FindingsFindings suggested that building and indoor environmental parameters of humidity, indoor temperature, volume, illumination, and window width ratio (WWR), in that order, influenced energy consumption significantly, and also, had direct empirical relationships.Practical implicationsOptimising the building and indoor environmental parameters in design will enhance energy-efficiency in university buildings in South Africa.Originality/valueThis study contributes to the literature in terms of understanding the order of influence of building parameters on energy consumption in university buildings in the temperate climatic zone of South Africa. It also established empirical models between building and indoor environmental parameters and energy consumption, both independently and in combination, that could assist in designing energy-efficient and sustainable university buildings.

scholarly journals Do energy performance certificates allow reliable predictions of actual energy consumption and savings? Learning from the Swiss national database

2020 ◽  
Vol 224 ◽  
pp. 110235 ◽  
Author(s):  
Stefano Cozza ◽  
Jonathan Chambers ◽  
Chirag Deb ◽  
Jean-Louis Scartezzini ◽  
Arno Schlüter ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Performance ◽  
National Database ◽  
Actual Energy Consumption
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