Energy Retrofit Measures Research Articles

Method for Assessment of Energy Retrofit Measures in Milieu Valuable Buildings

Proposed method concentrates on the junctions of structures that usually have strongest influence on visual character of the building. To gain energy savings, a major change of the influence occurs when external thermal insulation is considered without any changes in other parts of the building. Whole building renovation is preferred because all the different parts of the building can be taken into account and the energy savings are larger and overall influence on the architectural appearance is smaller. Energy performance of the historic wooden buildings can be improved significantly without negative influence on the architectural appearance and destroying the milieu value of the district.

Performance evaluation of a mechanically ventilated heat recovery (MVHR) system as part of a series of UK residential energy retrofit measures

This study involves a detailed analysis of a mechanically ventilated heat recovery (MVHR) system installed as a case study retrofit project in a UK test dwelling. Comparisons of predicted and in situ performance are made through the calculation of a theoretical and practical heat loss coefficient value (HLC).Analysis revealed underperformance in the installed MVHR system, as compared to predicted data. Issues were identified in the installation and function of the control unit and ductwork. Improvement work enabled the system to function more closely to optimum performance levels. However, discrepancies still existed between the predicted and actual HLC values, which were largely accounted for through theoretical heat loss calculations attributable to slight imbalances within the system supply and extract rates. When normalised, the data still showed an unaccounted heat loss of approximately 6W/K in both MVHR tests.The study reinforces the need for high quality MVHR installation and commissioning work, which is critical to ensure that a system can perform to the optimum levels specified in manufacturer literature. Education and training throughout the supply chain is essential in achieving this, as system inefficiencies can lead to unnecessary heat losses resulting from increased levels of air infiltration or leakage.

Climate change and thermal comfort in Southern Europe housing: A case study from Lisbon

The world has been experiencing a significant increase in daily average temperatures per decade and climate change scenarios are projecting high probability of more frequent heat waves. In vulnerable regions, like Southern Europe, where most of the residential buildings still rely on natural ventilation for cooling, impact on thermal comfort can be significant in terms of health, well-being and also energy consumption. The question is particularly important for the existing building stock, which was not designed considering the projected future climate conditions and is prone to be subjected to interventions with the purpose of improving thermal performance. The study presents a vulnerability framework and methodology for the assessment of thermal comfort in existing dwellings in the context of climate change. Results relating to a 1960s typical building case study in Lisbon, Portugal, suggest that specific dwelling characteristics, such as orientation, and occupancy profiles are relevant when assessing vulnerability, suggesting significant differences, of up to 91% in discomfort hours on an annual basis. Furthermore, increased insulation seems to be effective in decreasing discomfort, as the best results (48% in discomfort hours decrease) stem from a context of external insulation for a heatwave situation. The methodology can be useful for assessing vulnerability in existing dwellings and its specific conditions. It can also contribute to understanding the effect of energy retrofitting measures in future climate conditions, assisting energy efficiency policies and decision-making regarding retrofit interventions.

Energy audit of schools by means of cluster analysis

More than 30 % of the Italian schools have very low energy efficiency due to aging or poor quality of construction. The current European policy on energy saving, with the Commission Delegated Regulation (EU) 244/2012, recommends a cost-optimal analysis of retrofit improvements, starting from some reference buildings. One relevant issue is the definition of a set of reference buildings effectively representative of the considered stock. A possible solution could be found using data mining techniques, such as the K-means clustering method, which allows the division of a large sample into more homogeneous and small groups. This work adopts the cluster analysis to find out a few school buildings representative of a sample of about 60 schools in the province of Treviso, North-East of Italy, thus reducing the number of buildings to be analyzed in detail to optimize the energy retrofit measures. Real consumption data of the scholastic year 2011–2012 were correlated to buildings characteristics through regression and the parameters with the highest correlation with energy consumption levels used in cluster analysis to group schools. This method has supported the definition of representative architectural types and the identification of a small number of parameters determinant to assess the energy consumption for air heating and hot water production.

Analysis of energy efficiency retrofit scheme for hotel buildings using eQuest software: A case study from Tianjin, China

Hotel buildings generally consume more energy than other types of public buildings, so measures should be adopted to reduce their energy demands. Energy retrofit measures (ERMs) were explored by eQuest software, using the example of an existing four-star hotel in Tianjin, China. The study investigates predictive accuracy for the major factors in the energy consumption of hotel buildings. The results indicate that the schedules of internal loads have the most significant impact on the accuracy of the model for hotel buildings, followed by occupancy rate and coefficient of performance (COP) of the chillers. A retrofit scheme was formulated and its energy-saving potential was evaluated by the calibrated model. Post-implementation monitoring was carried out, and the similarity between model predictions and the actual outcomes of the retrofits confirms that the calibrated model provides a highly accurate forecast of the energy-saving effects of the building energy efficiency retrofit (BEER) scheme.

Using suite energy-use and interior condition data to improve energy modeling of a 1960s MURB

Abstract Energy modeling is a useful tool for evaluating the performance of contemplated building energy retrofit measures. Traditionally, energy models are developed using data collected from building floor plans and site visits and are then calibrated using utility bills. In the work presented here, an energy model for an existing multi-unit residential building (MURB) was developed using this traditional approach. Next, a refined approach was taken. Using data gathered from a suite-based monitoring program, input data uncertainties in the energy model were addressed. Data from one year of monitoring were assembled to characterize the actual building performance and to calibrate this refined energy model. In order to identify which parameters could be used to improve the model accuracy, the output of this refined model was compared to the output from the traditional modeling approach. It was found that the interior temperature measurements and the sub-metered suite electricity use were the most beneficial in refining the energy model. However, other data collected including window operation and differential air pressures were useful for determining how the building was operating. The use of a local weather file generated from a roof-top weather station has also been discussed.

Estimating energy savings for the residential building stock of an entire city: A GIS-based statistical downscaling approach applied to Rotterdam

Abstract Energy retrofit of buildings represents an important sector for mobilizing investments to address carbon mitigation of cities. The identification of the actual energy consumption profile of large building stocks is a necessary step to evaluate the impact of retrofit measures, e.g. energy savings, at city scale. The present study introduces a bottom-up statistical methodology based on a Geographical Information System (GIS) to estimate the energy consumption of residential stocks across an entire city. The adoption of a multiple linear regression model allows the downscaling of measured natural gas and electricity consumption from the aggregated post-code level to single dwellings, based on several descriptors, such as dwelling type, period of construction, floor surface and number of occupants. The energy consumption is apportioned to different end-uses and corrected for weather, then the energy savings potential is estimated by accounting for the implementation of typical refurbishment measures. Results are finally aggregated across the whole city for evidence-based decision support in sustainable urban planning. The study provided relevant results to prioritize the implementation of energy retrofit measures for the residential stock of Rotterdam city, consisting of about 300,000 dwellings. The methodology can be further applied to other contexts due to its generic nature.

Factors influencing German house owners' preferences on energy retrofits

In this paper, we identify key drivers and barriers for the adoption of building energy retrofits in Germany, which is promoted by public policy as an important measure to address the future challenges of climate change and energy security. We analyze data from a 2009 survey of more than 400 owner-occupiers of single-family detached, semidetached, and row houses in Germany, that was conducted as a computer-assisted personal interview (CAPI). In the survey, respondents were asked directly for reasons for and against retrofitting their homes, but also faced a choice experiment involving different energy retrofit measures. Overall, we find that house owners who are able to afford it financially, for whom it is profitable, and for whom there is a favorable opportunity are more likely to undertake energy retrofit activities. The latter point seems to be of particular importance in explaining the persistent low retrofit rate in Germany. Our results suggest that professional energy advice could stimulate the demand for building energy retrofits.

Development and implementation of a simplified residential energy asset rating model

Recent European legislation (Energy Efficiency Directive) has allocated some responsibility for residential end use energy efficiency to energy supply companies. In order to overcome data and modelling limitations associated with statistical and engineering modelling approaches to energy efficiency and renewable energy retrofit measures, energy suppliers and policy-makers often use simplified methods with limited data requirements to assess dwellings. One approach employed is an asset rating method (ARM); a standardised approach to residential energy demand estimation which is outlined in ISO EN 13790 (Energy Performance of Buildings Directive). Although it is a simplified method which industry is well-equipped to deliver, it is time-consuming to apply ARMs to the large domestic customer bases of energy suppliers. A small per-dwelling time saving will result in significant overall efficiencies for these users. This study examines the effect that reducing input data requirements of the ARM has on the accuracy of the methodology and comments on the trade-off between model simplification and accuracy. We find that it is possible to maintain a high degree of accuracy (∼95%) with 20 fewer variables than the baseline model. This is equivalent to almost 40% fewer variables than in the full model and represents a significant saving in effort

기존 건물의 에너지 개수방법의 제안 및 사례연구

Recently, energy saving in building sector is of great important to meet national <TEX>$CO_2$</TEX> reduction goals in Korea. In this sense, it is crucial to improve the energy performance for existing building. The energy efficiency investments, ESCO business, can be beneficial to expand the chance of energy retrofit for existing building. However, ESCO business hardly expand in Korea because it has many limitations in guarantee for energy saving. Also, it is more difficult to apply the energy retrofit measures in existing building than new building. Therefore, the retrofitting methods for existing small-and medium-sized buildings should be improved to initiate ESCO business and expand it in Korea. In this study, the energy retrofit methods for small sized office building were suggested and the case study for a small sized office building located in Suwon was accomplished.

Factors Influencing German House Owners’ Preferences on Energy Retrofits

In this paper, we identify key drivers and barriers for the adoption of building energy retrofits in Germany, which is promoted by public policy as an important measure to address the future challenges of climate change and energy security. We analyze data from a 2009 survey of more than 400 owner-occupiers of single-family detached, semidetached, and row houses in Germany, that was conducted as a computer-assisted personal interview (CAPI). In the survey, respondents were asked directly for reasons for and against retrofitting their homes, but also faced a choice experiment involving different energy retrofit measures. Overall, both the descriptive and econometric results show that house owners who are able to afford it financially, for whom it is profitable, and for whom there is a favorable opportunity, are more likely to undertake energy retrofit activities. Based on an estimated mixed logit error component model, we also simulate the incentive effects of different policy options, such as public subsidies and energy tax increases.

The Green Energy Audit, a new procedure for the sustainable auditing of existing buildings integrated with the LEED Protocols

Abstract Energy audits of buildings are the most effective tool to promote energy retrofitting measures for existing buildings, which are major consumers of energy in cities. Energy audits have multiple goals, including reducing energy consumption, managing costs, and environmental impact. The methodology of Green Energy Audit proposed defines an approach that is somewhat different from the traditional one. The added value lies in the word “ green ”, a word that refers to and summarises a common concept: sustainability. The proposed method is not intended to be a new energy auditing procedure, but rather a new and more modern interpretation of the classic methodology. The sustainability achieved by applying a retrofit measure is assessed with reference to the Leadership in Energy and Environmental Design Protocol. The Green Energy Audit integrates two strategic elements, energy and environment, by mixing the energy audit and LEED methodologies. This synergy strengthens the role of the classic energy audit by providing a method that not only optimise the energy performance of existing buildings but also achieve a green retrofit of buildings, making buildings, and so future cities, more sustainable. A case study of the application of this method is discussed in this paper.

Factors Influencing German House Owners' Preferences on Energy Retrofits

In this paper, we identify key drivers and barriers for the adoption of building energy retrofits in Germany, which is promoted by public policy as an important measure to address the future challenges of climate change and energy security. We analyze data from a 2009 survey of more than 400 owner-occupiers of single-family detached, semidetached, and row houses in Germany, that was conducted as a computer-assisted personal interview (CAPI). In the survey, respondents were asked directly for reasons for and against retrofitting their homes, but also faced a choice experiment involving different energy retrofit measures. Overall, both the descriptive and econometric results show that house owners who are able to afford it financially, for whom it is profitable, and for whom there is a favorable opportunity, are more likely to undertake energy retrofit activities. Based on an estimated mixed logit error component model, we also simulate the incentive effects of different policy options, such as public subsidies and energy tax increases.

Effectiveness of single and multiple energy retrofit measures on the energy consumption of office buildings

Energy retrofit measures (ERMs) are applied to reduce the energy consumption of buildings. The effectiveness of any ERM depends on many building specific factors, such as location, size, operation, building envelope, electrical, heating, cooling and ventilation system properties. It is common for multiple ERMs to be applied to a building to reduce its energy consumption. However, the reduction in energy consumption when multiple ERMs are applied is not the sum of the impact of individual ERMs. Effectiveness of multiple ERMs depends upon their interactive effects. Using representative office buildings and an energy modelling computer program, the effectiveness of individual and multiple ERM was assessed providing a better understanding of their interactive effects.

A screening methodology for implementing cost effective energy retrofit measures in Canadian office buildings

Private and public sectors own and operate an array of office buildings that consume energy and contribute to the emission of greenhouse gases (GHG). Energy demands can be reduced by applying energy retrofit measures (ERMs) to existing buildings. The choice of ERMs involves evaluation of applicability, energy end uses and cost of application versus energy savings. This paper describes a methodology developed to screen office buildings for their current level of energy consumption and potential for retrofit application. Selection of an optimal set of ERMs is influenced by climate, occupancy, heating and cooling systems, envelope properties and building geometry. When assessing the implications of applying ERMs to a large building stock it is vital to screen the complete building set for optimal retrofit opportunities. This can be accomplished by characterizing office building stock into a manageable set of archetypes and simulating building operation using energy simulation software. Using regression analyses, a model was developed for estimating the energy consumption. Present value analysis was used to optimize the evaluation of the various ERMs. The methodology developed can be used to simplify the ranking of buildings for retrofit; to select and combine ERMs, and to plan energy and GHG reduction activities.

The Energy Concept Adviser—A tool to improve energy efficiency in educational buildings

Educational buildings such as kindergartens, schools and universities display many similar design, operation and maintenance features in most countries. The two most noteworthy similarities amongst these building types are the high energy consumption and the necessity for retrofitting many buildings within this sector. However, studies have shown that during retrofit, energy saving measures are only rarely applied, because the decision-makers lack knowledge of investments and the efficiency of potential energy saving measures. The main goal of the International Energy Agency ECBCS Annex 36 is to provide the educational building decision-makers with sufficient data, information and tools to improve their learning and teaching environments by improving the energy efficiency of their buildings. This is the background for the development of an Energy Concept Adviser (ECA) for energy and financial retrofit measures that is useful during the planning and concept development phases for educational buildings. On the one hand to help the owner to find the most efficient energy saving measures and on the other hand to prevent that exaggerated expectations are raised. The ECA should be applicable during the entire retrofitting phase to ensure that both the calculated energy savings and financial success will be achieved after retrofitting. This paper describes a tool that assists educational building decision-makers while the construction project is still in the design phase. This tool will improve new or existing buildings through the identification and calculation of potential energy savings. The ECA includes suggestions of energy systems to use and potential design concepts to be considered during the design phase. During the past 6 years, data have been gathered from all the 10 participating countries of the Annex 36. This electronic Internet-based tool incorporates an interactive source book of information, which includes design concepts, design advise, design and decision programs, and case studies. The tool has been translated into several languages.

Development of a methodology for selecting office building upgrading solutions based on a test survey in European buildings

The potential for using the TOBUS methodology to select office building upgrading solutions have been investigated during field tests in 15 European office buildings in 5 European countries. The 15 office buildings represent a variety of building traditions, architectural designs, construction periods and energy and indoor performance. The buildings were audited following the TOBUS methodology developed within the project. The results of the test surveys were primarily used to improve the TOBUS methodology and secondly to suggest general upgrading solutions and energy retrofit measures for the surveyed buildings. This paper describes the development of the TOBUS methodology based on the 15 test surveys.

Residential energy and demand patterns as related to weather and conservation measures

Electrical energy consumption and the peak electrical demand were measured at two similar public housing sites in Selma, North Carolina. One site, designated as Preston Street (PST), had low cost energy retrofit measures combined with education of the occupants on energy efficient life styles. The other site, Canady Courts (CC), was originally planned as a control site. Both sites are single-storey wood-frame with brick-veneer construction. The sites consisted of a combination of efficiency and 1,2,3, and 4-bedroom units. PST consisted of 30 units with a total floor area of 22,000 ft2 and CC had 26 units with a total floor area of 18,800 ft2. Originally CC was intended to be used to quantify the impact of the energy conservation project undertaken at PST. This approach proved inadequate, and consequently an alternate methodology was employed. This method used the measured historical energy at both CC and PST to develop a database that could be used to predict the energy use that would be expected to occur at either site. If there are no changes at the site, then the predicted and measured energy use should agree. When conservation measures are instituted, the difference between predicted and measured energy use is the energy saving (or increase) due to the conservation measures. The report gives a description of the methodology that was used to analyse the historical data and the results and accuracy that were obtained. In addition, the problems with using one site as a control, as originally planned, are described. The Section on results gives a comparison of the predicted and measured energy use at both CC and PST for the calendar year 1985. The last part of the report deals with the investigation of the demand profiles and demand at PST. This analysis indicates the nature of the demand profiles at PST and thus the types of conservation measures that are likely to be the most effective in reducing demand.