While energy prices have increased substantially recently, we also observe that renovation prices have increased twofold wihtin last decade. This could seriously affect the motivation to invest in ...building renovations because of negative yield and in turn jeopardise the carbon reduction plans. Therefore, we attempt to show some evidence of renovation cost dynamics based on sample of 112 apartment buildings which received state support for deep energy renovations during 2010 and 2017. We found that investments started out very cautiously in 2010. Eventually renovations were embraced as rational investment and renovations ambitions grow with prices. Construction price index grow during the~study period 20 percent and renovations over two times. We could not confirm the popular hypothesis that demand pressure will also increase prices. However, most significant increase of renovation price was due to the additional construction works and quality improvement. This was especially evident after the redesign of grant rules in 2015 which allowed more indirect construction works to be eligible for the subsidy.
Buildings have become a major concern because of their high energy use and carbon emissions. Thus, a material-efficient prefabricated concrete element (PCE) system was developed to incorporate ...construction and demolition waste as feedstock for residential building energy renovation by over-cladding the walls of old buildings. By conducting life cycle assessment and life cycle costing using the payback approach, this study aims to explore the life cycle performance of energy conservation, carbon mitigation, and cost reduction of the PCE system in three European member states: Spain, the Netherlands, and Sweden. The results show that the energy payback periods for Spain, the Netherlands, and Sweden were 20.45 years, 17.60 years, 19.95 years, respectively, and the carbon payback periods were 23.33 years, 16.78 years, and 8.58 years, respectively. However, the financial payback periods were less likely to be achieved within the building lifetime, revealing that only the Swedish case achieved a payback period within 100 years (83.59 years). Thus, circularity solutions were considered to shorten the PCE payback periods. Using secondary materials in PCE fabrication only slightly reduced the payback period. However, reusing the PCE considerably reduced the energy and carbon payback periods to less than 6 years and 11 years, respectively in all three cases. Regarding cost, reusing the PCE shortened the Swedish payback period to 29.30 years, while the Dutch and Spanish cases achieved investment payback at 42.97 years and 85.68 years, respectively. The results can be extrapolated to support the design of sustainable building elements for energy renovation in Europe.
•Novel technological systems for recycling mineral construction and demolition waste were introduced.•A novel prefabricated concrete element system for renovating existing building (PCE2) was presented.•Comprehensive assessment of the PCE2 system under three EU member states was investigated.•How will material circularity strategies influence the energy-carbon-investment payback of the PCE2 was explored.
Green hydrogen has a significant potential in decarbonizing the energy system, and avoiding deforestation by replacing biomass fuels, meanwhile, implementing waste heat recovery from its production ...process can boost decarbonization in district heating networks. However, since hydrogen-consuming industries are often distant from district heating networks, waste heat recovery from electrolysis plants may cause additional cost of transferring hydrogen. This contribution investigates this systematic challenge by evaluating the possible benefits of integrating hydrogen production process into district heating networks and considering the additional cost of transferring hydrogen. In addition, this study quantifies the expected national system-level benefits of efficient building renovation strategies and the additional progress that coupling with hydrogen production could bring. Based on the results, while the economic benefits of importing waste heat from electrolysis plants into the district heating networks is relatively small (annually 100 M€, constituting roughly 0.4 % of the Finnish energy system annual costs), this study demonstrates its notable potential to reduce biomass consumption by 7 %. However, the required cost for transporting hydrogen in Finland is projected to be 0.1–0.2 €/kg. Moreover, the results reveal that buildings renovation in two levels of low-renovation and high-renovation can decline biomass consumption in the heating sector by 29 % and 40 %, respectively.
•Assessing the potential of electrolyzer waste heat in district heating systems.•Evaluating the side-benefits of green hydrogen in Finland's energy system.•An annual saving of 100 M€ is achievable by waste heat recovery from electrolyzers.•Over 7 % decline in biomass consumption by waste heat recovery from electrolyzers.•29–40 % decline in biomass consumption by energy renovation in buildings.
•A comprehensive review of optimizing energy performance of existing buildings is presented.•Studies are discussed according to their decision-making model, measures and variables, software tools, ...etc.•A table of reviewed studies is presented that provides an overview of previous works at a glance.•Gaps for future works in this research area are outlined.
Energy retrofit and renovation of existing buildings have an effective role in reducing carbon dioxide emissions and ultimately global warming. Therefore, there is an increasing interest in this field of research. The aim of this paper is to offer a complete, precise, up-to-date literature review on energy performance optimization of existing buildings.
The literature is analyzed and discussed towards decision-making model, measures and variables, objectives and criteria, software tools, optimization methods, case studies geographical locations and case studies building types. Finally, trends and future research opportunities are presented. The results of the review show that in spite of numerous conducted studies, some optimization objectives such as aspects of comfort conditions, except thermal comfort, and some types of weather conditions have been neglected. Additionally, there is a need for creating a novel decision-making tool reducing computational time of optimization and increasing reliability on the optimal packages. This article provides an extensive overview for researchers to define their outlines in this area.
With energy transition setting the ground for innovation and new ways of conducting business, one-stop shops (OSSs) have recently gained momentum in the renovation market. By transforming a complex ...set of multiple-actor decisions into a single entry and customer-centric service, OSSs have the potential of establishing a bridge between the fragmented demand and supply sides of the traditional renovation value chain. To assess the viability of the OSSs model as a vehicle of accelerating decarbonisation efforts in the European building stock, this paper collects and analyses 63 case studies of OSSs across Europe. The study offers insights into the dynamics of their business model, key benefits and ways forward, by explicitly exploring OSSs’ role in incentivising homeowners to decide to renovate. Our findings show that OSSs can be instrumental in addressing the multitude of barriers that prevent homeowners to renovate. With around 100,000 OSSs projects per year, their activity is expected to substantially contribute to the European renovation targets to rise, subject to favourable policy framework, availability of affordable financing solutions and experience sharing within and across countries. With some OSSs already supporting vulnerable households to renovate, OSSs might be well-placed in the future to contribute to tackle energy poverty by assisting in accessing financing and engaging property owners to renovate.
This study analysed renovation measures implemented with ARA renovation subsidy in Finland in multifamily apartment buildings. Measured energy data was used to calibrate the energy simulation model ...of the most typical renovated building from the 1970 s. For the reference building, a comprehensive set of renovation packages were applied to assess the performance of ARA grants. It was noticed that official energy performance certificates (EPC) overestimated before the renovation energy use as well as energy saving by a factor of almost 2. It was notable that in calculated EPCs, after renovation, EP-value was higher than before renovation, EP-value based on measured energy use. The main reasons for faulty energy calculations were strong overestimations in the building leakage rate and ventilation airflow rate. Renovation packages reduced EP-value by 8 % to 27 %, including lighting and appliances. Those using district heat resulted in a small increase in electricity with a flat duration curve, but the combined ground source and exhaust air heat pump showed the highest peak electricity power increase by factor 6. Exhaust air heat pump, window replacement and photovoltaic were the most cost-effective options, while packages with additional insulation faced considerably higher costs than the sum of ARA support and monthly savings could cover bank loans; thus, ARA support was clearly too small to support deep renovation. The need to improve the accuracy of EPCs in assessing energy performance to facilitate more effective financial support was a finding that can be important for any support scheme to secure the necessary funding for renovation.
•Analyzed the effect of minor renovation of buildings in terms of energy savings.•Minor renovations should consider the equipment capacity and energy source.•Passive strategy to reduce energy demand ...should be formulated before renovation.•Minor renovation helps improve energy performance of existing buildings.
The world is attempting to achieve zero energy in new buildings and realize energy savings in existing buildings by renovating them. The Korean government is also conducting a project to support the renovation of aging small public buildings. As minor renovation is mainly performed when the renovation is not activated, this study aims to analyze the effect of minor renovation by comparing the effects of buildings that have undergone minor renovation. The subjects of the analysis were 16 daycare centers that had undergone minor renovations; these buildings were divided into passive, active, and passive + active groups according to the applied energy-saving measures. The passive + active group exhibited the highest energy-saving effect, whereas the passive group showed the highest cost-effectiveness. Therefore, when performing minor renovations, the equipment capacity and energy source must be considered, and a passive strategy to reduce energy demand should be formulated. This study is expected to contribute to the expansion of the renovation of existing buildings by verifying the effects of renovation according to energy-saving measures.
Energy renovation faces critical challenges due to upfront costs and operational complexities, impeding its widespread adoption. Some strategies have initiated a groundbreaking economic model ...featuring a third-party payment mechanism. Under this innovative scheme, households redirect their energy bill savings to a third-party operator to fund renovation projects. In this study, employing a controlled laboratory experiment, we examine the diversity in preferences regarding this government policy and investigate the influence of informational tools on individuals' intentions to participate in the program. Our findings reveal that households with a strong environmental orientation, a penchant for risk-taking, and more altruistic and patient are more inclined to express interest in this program. Surprisingly, information designed to activate social norms and instill confidence in government intervention does not significantly enhance adoption intentions. Our experiment offers valuable methodological insights that can inform the implementation of effective energy renovation initiatives.
•Different renovation intervention levels are evaluated.•The technoeconomic feasibility by itself does not explain the actual renovation rates.•Existing social, material and legal barriers are key ...for a comprehensive analysis.•Measures should be taken to boost district/building level interventions.
Building is one of the main sectors in which significant energy savings can be achieved with a consequent reduction in emissions. This paper assesses the large-scale renovation of buildings, exploring the quantitative and qualitative factors that determine their replicability potential from three different perspectives, namely dwelling, building and district intervention level. Different passive and active measures are assessed, covering energy saving measures, the improvement of energy supply systems and the integration of renewable energy sources. Different scenarios are defined for each intervention level, which are evaluated using the methodology developed in the IEA-EBC Annex 75 project. The methodology is applied to a residential district located in Bilbao (Northern Spain). The analysis is based on the results obtained from the simulation of 41 combinations of different renovation options, obtained by simulation in the Design Builder software. The assessment is carried out from the evaluation of different key performance factors, including annualised cost and annual primary energy consumption, as well as the CAPEX and OPEX requirements. The results show that energy renovation of buildings offers a great opportunity for energy reduction at affordable investment costs, obtaining the cost optimal values when the intervention focus on the energy system and reaching net NRPE values close to zero when the intervention is carried out in a comprehensive way, considering energy systems and thermal improvement of the envelope. Additionally, the different energy reduction scenarios show that, while interventions at district level offer the greatest potential for minimising annual costs and primary energy consumption levels, intervening at building level offers only slightly worse results. However, there are other issues which can better explain the current low rate of renovation works in the urban environment. Thus, if the additional existing social, material and legal barriers and constraints are included in the analysis, it becomes clear why renovation from a district perspective is not actually leading the race. Given this situation, some measures and policies are proposed to realise the true potential of large-scale building renovation.
District heating networks increasingly rely on heat pumps, condensing biomass boilers, and excess heat in the transition to sustainable energy systems. Accordingly, district heating operators seek to ...reduce their networks’ supply and return temperatures to maximise production efficiencies, minimise heat losses from distribution pipes and allow greater utilisation of renewable heat sources and excess heat. Experts have predicted that investing in solutions that reduce heating temperatures in buildings will yield a return on investment of 300% for district heating operators. Therefore, expecting incentives, building operators should identify methods to reduce supply and return temperatures to enable a rapid, widespread transition to low-temperature district heating. Ample research has investigated and documented the feasibility of low-temperature heating in buildings, and this paper presents the first comprehensive review. It synthesises available literature and adds new perspectives to help guide future implementation, research and development of low-temperature heating. The energy and temperature demands of various heating systems provides a background, leading to a review of typical malfunctions and their impacts. The article subsequently reviews the obtainable supply and return temperatures before and after renovating the building envelope and heating systems. It further identifies and summarises vital measures for decreasing heating system temperatures. Ultimately, the authors recommend minimising heating system temperatures using automatic balancing of space heating and ventilation systems, novel solutions for safe domestic hot water supply, and digitally-enabled performance monitoring and optimal control.
•Review of the energy and temperature demands for various heating systems.•Review of typical heating malfunctions in buildings served by district heating.•Review of the obtainable supply and return temperatures pre- and post-renovation.•Review of technical improvements to achieve low-temperature operation in buildings.•Key prospects and research areas for improving low-temperature heating systems.
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