Optimizing building retrofit through data analytics:A study of multi-objective optimization and surrogate models derived from energy performance certificates

The building stock is responsible for a large share of global energy consumption and greenhouse gas emissions,therefore,it is critical to promote building retrofit to achieve the proposed carbon and energy neutrality goals.One of the policies implemented in recent years was the Energy Performance Certificate(EPC)policy,which proposes building stock benchmarking to identify buildings that require rehabilitation.However,research shows that these mechanisms fail to engage stakeholders in the retrofit process because it is widely seen as a mandatory and complex bureaucracy.This study makes use of an EPC database to integrate machine learning techniques with multi-objective optimization and develop an interface capable of(1)predicting a building’s,or household’s,energy needs;and(2)providing the user with optimum retrofit solutions,costs,and return on investment.The goal is to provide an open-source,easy-to-use interface that guides the user in the building retrofit process.The energy and EPC prediction models show a coefficient of determination(R2)of 0.84 and 0.79,and the optimization results for one case study EPC with a 2000€budget limit inÉvora,Portugal,show decreases of up to 60%in energy needs and return on investments of up to 7 in 3 years.

Energy, Social and Economic Indicators for Evaluation of Retrofit Buildings： The Brazilian Perspective on Sustainable Development

This paper aims to establish a methodological frame work and its validation as a response to the need of a demand management tool in the face of recurring comparisons of building revitalization or retrofits. As the investment and implementation actions improve and the social economic criteria are delimited by regulatory frameworks, it is extremely necessary to monitor previous performances and further prospects, regarding projects, it is necessary to measure the extent of which efforts have been meeting regulatory requirements and aiming to contribute with sustainable development. In this context, the use of indicators has been a major management tool.

Amelioration and retrofitting of educational buildings

Following a seismic event that occurred years ago in Central Italy, the public opinion was growing and growing a concern on the adequacy of educational buildings all across Italy. This activated several political decisions and a consequent technical effort is in progress. Technically speaking one has to manage the classical problem of retrofitting existing buildings. However, the legal environment goes across national codes, targeted guidelines and the professional need of achieving pragmatic solutions based on ethical and social acceptation schemes.This paper introduces the topic in its worldwide exception and focuses then on some operative aspects in the Italian situation. It outlines the consolidated steps along this technical process and emphasizes the weak aspects one meets when going across the designers＇ reports.

A pragmatic retrofitting approach to enhancing the thermal,energy and economic performance of an educational building:a case study in Malaysia

Building retrofit procedures play a crucial role in improving the energy performance and economic indicators of a building.In this context,an energy audit is typically recommended,but it is seldom used as a comprehensive approach due to the complexity and associated costs.This article aims to conduct a holistic energy audit approach for a university building in Malaysia,with the objective of diagnosing energy efficiency deficiencies,identifying areas of energy waste and proposing practical retrofit measures accordingly.The approach involved multiple stages,including measurements,surveys and simulation work.Eight energy-saving measures were proposed,targeting improvements in envelope elements,cooling and lighting systems,and operation and control.The Design-Builder software was utilized for energy simulation,assessing the annual energy savings.Economic evaluation indices,such as net present value and simple payback period,were used to assess the economic feasibility of the measures.The results demonstrated significant potential for energy reduction,with each measure achieving annual energy reductions ranging from 2%to 18%,and a cumulative im-pact of 41%on annual energy consumption when combined.The investment payback period for the energy-saving measures varied from 0.8 to 8.9 years,with a payback period of 3.9 years for the combined energy-saving measures.Furthermore,the net present value was positive,indicating the economic feasibility of investing in the proposed energy-saving measures.These findings provide valu-able energy-saving opportunities that can be applied to improve similar buildings on the university campus.

Characterization of housing stock for energy retrofitting purposes in Spain

Energy saving in existing buildings is of vital importance.In this work,the characterization of housing stock in Spain for energy retrofitting purposes has been performed.The regulations in force when the existing stock was constructed(1980–2007)were considered to model the envelope and thermal systems of single-family and block housing.Building energy consumption and CO_(2) emissions were estimated for each type of dwelling and location,ranging from 44.2 to 130.6 kWh/(m^(2)·year)(13.6–32 kg CO_(2)/(m^(2)·year))for multi-family homes,and 85.5 to 213.5 kWh/(m^(2)·year)(17.1–45.2 kg CO_(2)/(m^(2)·year))for single-family homes.A global picture of the energy performance and emissions for 13 different climate zones was obtained with a total of 504 simulations.Retrofitting of the envelope allowed the reduction of consumption and emissions from 37.7%to 58%,depending on the climate zone.Energy consumption per square meter in block housing was lower than in single-family housing;nevertheless,single-family houses responded more effectively to energy improvement actions.Finally,non-renewable primary energy savings seem a better indicator of the improvement by retrofitting than the energy label.The building models designed in this work may serve as a reference for subsequent research concerning energy retrofitting and energy savings of housing stock.

Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil

The paper deals with the energy and indoor comfort on buildings of UPF （University ofPasso Fundo）, located in southern Brazil, in order to improve the eco-efficiency concepts in the university＇s building stock, reinforcing its responsibility towards sustainable development. The factors that affect thermal performance and the energy consumption of two case studies were identified, including the general characteristics of the envelope and the indoor conditions. The simulations with DesignBuilder software compare the energy and thermal performance of both cases： those results allow the identification of their positive and negative aspects, as well as making a co-relation with the students＇ sensations of comfort--obtained through PMV （predicted mean vote）. The research indicates that it will be possible to improve eco-efficiency of existing and new buildings and campuses by retrofitting and upgrading it with regard to better indoor conditions that really correspond to climate conditions （hot and humid summers, and cold and damp winters）, using passive strategies for heating and cooling and at the same time to improve rational use of natural resources and to reduce the environmental impact. Probably, giving comfortable conditions to the users will increase energy consumption, but there is a potential reduction of lighting and equipment that could minimize this impact.

Potential application of a novel building-integrated solar facade water heating system in a subtropical climate:A case study for school canteen

The design and potential application analysis of the novel solar-absorbing integrated facade module and its corresponding building-integrated solar facade water heating system are presented in this study.Compared with the conventional building envelope,the main novities of the proposed facade module lie in its contributions towards the supplied water preheating to loads and the internal heat gain reduction.Besides,the proposed building-integrated solar facade water heating system broadens the combination modes of the solar thermal system and the building envelope.A dynamic model is introduced first for system design and performance prediction.To evaluate the energy-saving potential and feasibility of the implementation of the proposed facade module,this paper carried out a suitable case study by replacing the conventional facade module in the ongoing retrofitting project of a kitchen,part of the canteen of a graduate school.The detailed thermal performances of three system design options are compared in the typical winter and summer weeks and throughout the year,and then,with the preferred system design,the economic,energy,and environmental effects of the proposed system are evaluated.It was found that the system with a high flow rate of the circulating water is suggested.The annual electricity saved reaches 4175.3 kWh with yearly average thermal efficiency at 46.9%,and its corresponding cost payback time,energy payback time,and greenhouse gas payback time are 3.8,1.7,1.7 years,respectively.This study confirms the feasibility and long-term benefits of the proposed building-integrated solar facade water heating system in buildings.

A bi-objective optimization approach for selection of passive energy alternatives in retrofit projects under cost uncertainty

Improving energy performance of buildings is of particular importance in new construction and existing buildings.Building refurbishment is considered a practical pathway towards energy efficiency as the replacement of older buildings is at a slow pace.There are various ways of incorporating energy conservation measures in buildings through refurbishment projects.As such,we have to choose among various passive or active measures.In this study,we develop an integrated assessment model to direct energy management decisions in retrofit projects.Our focus will be on alternative passive measures that can be included in refurbishment projects to reduce overall energy consumption in buildings.We identify the relative priority of these alternatives with respect to their non-monetary(qualitative)benefits and issues using an analytic network process.Then,the above priorities will form a utility function that will be optimized along with the energy demand and retrofit costs using a multi-objective optimization model.We also explore various approaches to formulate the uncertainties that may arise in cost estimations and incorporate them into the optimization model.The applicability and authenticity of the proposed model is demonstrated through an illustrative case study application.The results reveal that the choice of the optimization approach for a retrofit project shall be done with respect to the extent of variations(uncertainties)in expected utilities(benefits)and costs for the alternative passive technologies.

Achieving energy efficiency in government buildings through mandatory policy and program enforcement

Government buildings are responsible for a significant proportion of energy consumption worldwide,for example, in Australia, up to 41.5 PJ energy was consumed by government buildings in 2011–2012. While the newly constructed buildings may be energy efficient,the existing buildings, which account for more than 85% of the total building stock, were built prior to the time when energy rating systems was put in practice and are consequently energy inefficient to a large degree. Reducing the energy consumption in existing government buildings is essential, as it will not only reduce the costs and environmental impacts, but also show governments' strong commitment towards the reduction of greenhouse gas emission. Furthermore, successful building energy retrofit projects are the showcases to the general public, encouraging other sectors(e.g. commercial) to conduct building retrofits for energy savings. Recognising these benefits,several state governments in Australia have introduced building energy efficiency policies and programs. This paper reviewed the energy efficiency policies/programs in five States in Australia: Victoria, New South Wales, South Australia, Western Australia, and Queensland in terms of respective policies and targets, implementation methods and current progress. The lessons learned from these programs were also discussed. This research revealed that the key factors for a successful government buildingenergy retrofitting program are 1) having a properly enforced energy efficiency mandate with clear energy saving targets, 2) establishing an expert facilitation team and 3) implementing suitable financing and procurement methods.