Efficiency Retrofit Research Articles

Keep out the cold: An analysis of potential gaps in fuel poverty policies in Ireland

Fuel poverty in Ireland is a significant issue faced by almost a quarter of the population as per government statistics. In this study, we analyse fuel poverty data in Ireland between 2008 and 2020 using the Irish subset of EU SILC data. We find that the increase in the proportion of households receiving Fuel Allowance and the decrease in the proportion of poor-quality dwellings have a significant positive impact on the decline in aggregate fuel poverty experienced. We also analyse a sample of low-income households that experience fuel poverty and compare groups that are targeted by official policies with others on key indicators. We find that the existing supports normally target lower-income households who live in energy-inefficient dwellings and are of retirement age. We also find that non-targeted larger urban families who live in rented or mortgaged dwellings experience significant fuel poverty due to difficulty paying bills. We identify some gaps in the current policies that target fuel poverty. We propose that fully funded energy efficiency retrofits and social transfers for vulnerable households to help with the cost of heating, which are policies already used in Ireland to target fuel poverty, should be expanded to effectively reach a cohort of the population that is facing challenges to keep warm.

A procedure set to construct the optimal energy saving retrofit strategy for old residential buildings in China

A key strategy for lowering emissions and reducing the effects of climate change is to execute energy-saving retrofits in residential buildings. Despite extensive research on different retrofit pathways for building energy efficiency, the current retrofitting of the aged housing stock in China is still constrained by several factors, including occupant willingness, government financial situation, and low energy prices, so retrofitting projects are almost entirely government-led and most of the solutions of existing studies are not applicable. Therefore, a comprehensive optimization framework for low-budget compliance retrofit strategies in the Chinese context is urgently needed. In order to fill this gap, this study established a set of procedures for developing an optimal energy-saving retrofit scheme in old residential buildings in Nanjing city. The results showed that the optimal scheme can reduce 18.52% of residential building energy consumption in five central districts of Nanjing City, and the total energy saving is about 260.43 GW h. The study also showed that improving wall insulation and heating, ventilation, and air conditioning systems were the most efficient retrofit measures but came at a high cost. Setting a reasonable air conditioning target temperature was further identified as the most cost-effective retrofit measure. This study provided a mechanism for district-level retrofit planners to formulate a strategy that may take the performance of retrofitting on the environment and the economy into account while still adhering to code requirements.

Retrofitting Historic Buildings for Future Climatic Conditions and Consequences in Terms of Artifacts Conservation Using Hygrothermal Building Simulation

Climate change will greatly influence the world at several levels and will have consequences on the interior climate of historic buildings and artifacts conservation. Buildings are responsible for a large slice of the overall emissions, which is due both to the greenhouse gases that are released during their construction as well as the activities that are performed therewithin. One way of counteracting this trend is to design more efficient retrofit buildings and predict their behavior using simulation software, which can thoroughly assess the performance of new buildings or the impact of each retrofit measure for existing buildings. In this study, a calibrated computational model of high thermal inertia building was used to assess the performance of passive retrofits in mitigating the effects of climate change concerning artifact decay mechanisms. In addition, a methodology that aims to reduce the amount of time spent to perform these studies is also presented, in which time savings reach up to 63%.

Determinants of energy efficient retrofits in residential sector: A comprehensive analysis

Energy-efficient retrofits (EERs) are probably the most cost-effective method to address energy poverty in the residential sector. However, actual EER rates are far below those called for in recent policy goals. A large body of literature has examined the determinants influencing households’ EER decisions but with scattered and contextually limited results. Consequently, there is a lack of a comprehensive quantitative analysis of the literature in this area. In this study, a detailed literature review and bibliometric analysis of the determinants of EERs was conducted to better understand the scope and evolution of knowledge in this area. Specifically, 1198 scientific documents were systematically examined, with 1000 terms included in the final analysis. In addition, a new approach to bibliometric analysis was adopted, examining the content of abstracts rather than keywords, allowing for a more detailed analysis. This work contains important contributions. First, the result of this research is a detailed overview of the determinants of EER in residential buildings, which can be divided into five main groups: information and policy measures, economic factors, socioeconomic characteristics of households, technical and building characteristics and behavioural factors. Second, I conducted a bibliometric analysis that visualises the current state of knowledge regarding the determinants of EER in the literature. The results show that several groups of these determinants have been identified in the literature, the most influential of which are thermal comfort, energy cost, sustainable retrofit and behaviour change. These groups include 83 factors that are most relevant in the literature. Third, this study provides the historical evolution of the most influential EER determinants over the past three decades. The study suggests that future energy policies should use a mix of approaches to promote EER to comprehensively address the identified groups of determinants and multiple aspects of household members’ decision-making process.

A Rational Plan of Energy Performance Contracting in an Educational Building: A Case Study

Energy performance contracting (EPC) is the best solution for an educational building to implement energy conservation measures (ECMs) because of its high capital expenditure and operational expenditure needed for retrofit and maintenance. It is also considered a win–win mechanism for organising building energy efficiency retrofit projects. It aims to assist educational buildings in acquiring new high-efficiency equipment and maximising energy use reduction, as guaranteed by energy service company (ESCO). This study developed an EPC model using regression analysis, in which the inputs are based on the data collected during the preliminary energy audit in University A. As a result, with a quantum sharing ratio of 0.95/0.5 for ESCO/University A, the forecasted energy savings from the proposed ECMs, chiller optimisation and replacement, lighting retrofit, and energy management system are estimated to save 25.6% energy use, which reduces 5,672,057 kilowatt-hour (kWh) in electricity consumption; saves RM 2,762,291.76/year; carbon dioxide (CO2) mitigation equal to 3,771,061.22 kgCO2/year; return of investment of 4.2 years with a 5% interest rate; and building energy intensity of 93.55 kWh/m2/year. A sensitivity analysis of various quantum sharing ratios found that the saving value of ESCO is inversely proportional to that of University A as the client when the quantum sharing ratio for the former is increasing.

How Climate Action Plans are modified by the energy crisis? A focus on residential heating in Bristol

The recent surge in European energy prices could substantially reduce the social cost of Climate Action Plans. This paper conducts an ex-ante Cost-Benefit Analysis of mitigation policies in residential heating and studies the extent to which rising energy prices modifies their cost-effectiveness. I use the city of Bristol (UK) as a case study and assess two options: (1) investing in district heating networks in central districts or (2) subsidizing energy efficiency retrofits for least efficient dwellings. Implementing either of the two policy options under high energy prices trends increase economic benefits to households by around £ 1 per pound invested, in present value, relative to a scenario with baseline energy prices trends. Besides, district heating networks become more cost-effective at mitigating carbon emissions than energy efficiency retrofits.JEL classification: D61, Q41, Q48, Q58

Estimates of Long-Run Energy Savings and Realization Rates from a Large Energy Efficiency Retrofit Program

Estimates of Long-Run Energy Savings and Realization Rates from a Large Energy Efficiency Retrofit Program

Application of McKinsey Curve in Building Emission Reduction Technology

In order to promote the application of McKinsey energy reduction cost curves in buildings, This paper introduces the concept of McKinsey abatement cost curves, the current application status of building abatement measures and abatement cost data, makes an analysis for the economic characteristics of different energy efficiency measures in retrofit projects, and presents the retrofit measures, annual energy savings and investment costs used in retrofit programs by taking the example of energy efficiency retrofits in office and commercial buildings in the past 2 years, discloses the data changes in abatement costs for some energysaving retrofit technologies contrastingly, and suggests that dates should be iterated based on McKinsey abatement cost curves. The McKinsey abatement cost ctuve is usefill for guiding the selection of building energy efficiency measures. The curve is economical and visualized compatibly and is a good reference for making abatement decisions through timely updating the data of retrofit technologies and influencing factors.

Pro-social concerns characterise landlords’ energy efficiency retrofit behaviour: evidence and implications for energy efficiency policy in Victoria, Australia

Internationally, rental properties have fewer energy efficiency features than other homes, causing unnecessary carbon emissions and poor health outcomes for tenants. Landlords are the primary decision-makers for energy efficiency retrofitting of rental properties, yet their retrofit behaviour is not well understood. We surveyed 500 small-scale private landlords in Victoria, Australia, to examine how a range of variables impacted landlords’ energy-efficient retrofitting. Landlords who installed more retrofits were more likely to have greater concern for tenants’ comfort, a relationship with the tenant, or greater knowledge of property conditions. Despite the existing literature and in contrast to the research on owner-occupiers, financial variables, environmental concerns, and sociodemographic variables were not associated with landlords’ retrofitting. We propose that policies may be more effective if they are framed in pro-social (rather than pro-environmental or financial terms) and convey information about the impact of property conditions on tenants’ wellbeing.

House energy efficiency retrofits and loan maturity

Purpose The purpose of this study is to examine how households opt for their loan’s duration when it comes to energy efficiency retrofits (EERs). The primary focus is on the time horizon that these types of EERs will provide benefits to the households. Design/methodology/approach This study examines the second wave of the largest EER support program in Greece in recent years. The authors exploit an idiosyncrasy of the support program which offered interest-free loans. The baseline sample of this study includes approximately 18,000 households awarded the support and opted for a loan. To provide robustness and complement the analysis, the authors also use data from 38,000 households that were awarded support from the first wave of the EER program. Findings This study finds that EER investments that are likely to deliver longer-term benefits, in the form of energy savings, are positively associated with longer duration. This finding implies that households view such EERs as long-term investments that will consistently provide benefits in the future, thereby tolerating a longer period of incurring the inconvenience of paying monthly installments. Practical implications This study posits that an EER can be perceived by the household as an investment that saves money in the long term because of more efficient energy use. To this end, the authors bring forward the duration of the benefits accrued to the household as a driving factor to the household’s decision over the length of the loan. Originality/value This study expands on prior literature that has focused on consumer and loans for durables (e.g. cars) by examining EERs. However, EERs are different, as they can save households money in future periods. In addition, house EERs are at the forefront of energy policies and the design of future support programs at the epicenter of several initiatives.

Analysis of Occupant Behaviours in Energy Efficiency Retrofitting Projects

This review of studies into Energy Efficiency Retrofitting (EER) has shown the practice of EER to be a key factor in sustainability regeneration. Thus, the retrofitting practice itself (the way it is organised) has received increasing attention from both practitioners and researchers, and studies are now addressing some issues that are affecting the retrofit level of achievement. Most of the risks which lead to low retrofit development are related to owners. This paper aims highlight the role of the occupants in achieving the goals of EER. It is found that: (a) the early involvement of occupants in the design and construction stage, (b) mutual engagement, and (c) an integral approach that involves the occupants are the key to motivate EER decisions from these same occupants. It follows that this involvement, including the demographic characteristics of the occupants, such as their culture, habits, preferences, awareness towards energy saving and socio-economic factors, are indeed effective in influencing the energy-related behaviours of these occupants. Moreover, other factors, such as space-heating behaviour, presence/absence of the occupants, control level of the equipment and window, and lighting control behaviour, are all effective factors in the energy performance of the buildings. Hence, socio-technical advancements, co-design processes and effective energy efficiency policies are recommended strategies to: (a) improve occupants’ behaviours; and (b) increase their participation in EER projects.

A Review on Technical Challenges and Possibilities on Energy Efficient Retrofit Measures in Heritage Buildings

For heritage buildings, energy-efficient retrofitting cannot be applied with the same range of possibilities as with existing buildings. Applying such improvements to heritage buildings can be challenging due to their historic and/or cultural significance and non-standard construction methods. This paper reviews the technical challenges and potential of applying energy efficient retrofit elements in heritage buildings. The retrofitting measures reviewed are draught-proofing, windows, insulation, ventilation, heating, solar photovoltaics and phase change materials. It is possible to significantly reduce energy use in heritage buildings with such retrofits. However, there is no universal way to apply energy-efficient retrofitting in heritage buildings, which is apparent in the literature, where case studies are prevalent.

Water Efficiency Households Retrofit Proposal Based on Rainwater Quality in Acapulco, Mexico

Climate change, urbanization, and population growth, particularly in urban areas such as Acapulco, Mexico, put pressure on water availability, where although surrounded by water, the inhabitants lack enough good-quality water, especially in the rainy season. In addition, water scarcity, socioeconomic factors, and infrastructure problems limit the satisfaction of water demand in this context, e.g., operational issues in the water treatment plants and problems in the distribution network caused by hurricanes. The objectives of this research were: (i) to determine the rainwater quality in Acapulco, Mexico; (ii) to propose a domestic water efficiency retrofit (WER) design implementing a rainwater harvesting system (RWHS); and (iii) to determine the RWHS efficiency in terms of economic savings, considering rainwater’s social acceptance for domestic consumptive uses. The WER design was developed in an SFH in Acapulco, Mexico. The RWHS catchment surface area was 29 m2. The device comprises a first-rain separator (20 L) and a storage tank (1200 L). The rainwater harvesting potential (RWHP) was evaluated during the 2020 and 2021 rainy seasons, whereas the harvested rainwater quality (HRWQ) was analyzed in samples from 2021. Alkalinity, pH, electrical conductivity, total dissolved solids, chlorides, nitrates, sulfates, and heavy metals and potentially toxic metalloids were analyzed. Additionally, 168 surveys were applied to SFH owners to evaluate WER acceptance. Results showed that the RWHP was ca. 44 and 21 L/m2 in 2020 and 2021, respectively. All the rainwater quality parameters met the World Health Organization guidelines for consumptive uses except for drinking water. The perception study showed a 95% willingness to adopt the WER. Due to the RWHP and the HRWQ, the WER of SFHs is a promising solution to address Acapulco hydric stress under the nature-based solutions approach.

Estimating Space-Cooling Energy Consumption and Indoor PM2.5 Exposure across Hong Kong Using a City-Representative Housing Stock Model

High-quality data on building energy use and indoor pollution are critical to supporting government efforts to reduce carbon emissions and improve the population’s health. This study describes the development of a city-representative housing stock model used for estimating space-cooling energy use and indoor PM2.5 exposure across the Hong Kong housing stock. Archetypes representative of Hong Kong dwellings were developed based on geographically-referenced housing databases. Simulations of unique combinations of archetype, occupation, and environment were run using EnergyPlus, estimating the annual space-cooling energy consumption and annual average PM2.5 exposure concentrations under both non-retrofit and retrofit scenarios. Results show that modern village houses and top-floor flats in high-rise residential buildings, on average, used 19% more space-cooling energy than other archetypes. Dwellings in urban areas had lower exposure to outdoor-sourced PM2.5 and higher exposure to indoor-sourced PM2.5 compared to those in rural areas. The percentage decrease in space-cooling energy consumption caused by energy efficiency retrofits, including external wall insulation, low-e windows, and airtightening, varied significantly based on archetype. The implementation of external wall insulation in the housing stock led to an average decrease of 3.5% in indoor PM2.5 exposure, whilst airtightening and low-e windows resulted in 7.9% and 0.2% average increases in exposure, respectively.

Methods on reflecting electricity consumption change characteristics and electricity consumption forecasting based on clustering algorithms and fuzzy matrices in buildings

The extraction and analysis of electricity consumption changing patterns are increasingly important, as they can guide in energy management and efficiency retrofitting. Consequently, it is necessary to extract the laws governing building electricity consumption characteristics. This method should be on an hour-scale and successfully applied online to various buildings. Under these conditions, the method should be as simple as possible to ensure excellent online applications. A matrix model method was developed based on the conventional K-nearest neighbour clustering algorithm, which introduced the concept of electricity intensity levels. This method used the slopes of the power consumption curve as the grading standard for the extraction and assessment of the electricity consumption laws. The validation results for seven different buildings with various functions and climate zones, including the mean absolute error, mean absolute percentage error, mean square error, root mean square error, and coefficient of variance, showed that this method met the aforementioned requirements. Moreover, this method can be used for power consumption prediction, which integrated a process of filtering historical data, leading to better accuracy and less data volume than that of other methods that use historical data for prediction. Practical application This paper proposed a matrix model method based on the conventional K-nearest-neighbour clustering algorithm, which introduced the concept of electricity intensity levels. This method was applied to various buildings online, which coupled the process of filtering historical data and flexible selectivity of models when used on different buildings. This method was used for assessing energy-saving potential, energy-saving retrofit priorities, and power consumption forecasting, which will benefit researchers and engineers.

An Investigation of Occupants’ Energy Perceptions in Energy Efficient Retrofitted Residential Buildings: A Review Paper

Buildings are the main sector in energy consumption and CO2 emissions. Retrofitting of existing building has been identified as one of the significant strategies for reducing the impacts of buildings on energy and environment. However, recent studies have shown that low energy buildings mostly do not perform as expected. These differences are related to different factors including the interaction between occupants and building technologies. Thus, most renovation initiatives have not considered occupant behavior equally to the energy efficiency process. Many of the existing studies have been focused on technological improvements rather than behavioral-related parameters. Hence, this study aims to review the literature on the occupants’ energy perceptions and their behavioral interventions in energy efficient retrofitted residential buildings. The results of the literature review reveal that household’s energy consumption significantly differs according to the various factors including social-economic, cultural, household composition as well as individual attitudes, habits, experiences, and occupant practices. Moreover, the energy consumption in the residential sector is highly dependent on demographic parameters. The demographics factors are classified according to type of family, level of income, age of the occupants, and individuals’ educational status. The findings shows that energy perception gap formulates the energy behavior and it is related to the lack of personal interest, accurate information and individuals’ awareness about how to consume efficiently. Therefore, it is suggested that the level of occupant’s perception on energy, control, or comfort have to be considered during energy efficiency retrofits. The study contributes to understanding of occupants’ behaviors which cause energy performance gap and enlighten approaches to encourage more energy efficient behavior.

Active and Passive Solutions for an Energy Efficient Building

In addition, the majority of electricity consumed in buildings (58%) should come from renewable sources. Together with solar thermal, modern biomass, and district heating, overall renewables could ramp up to 81%, from 36% today’s contribution for the sector. Nonetheless, to materialize these predictions, a global investment of around USD 32 trillion (28 trillion euros) is expected between now and 2050. In the European Union, the nearly zero-energy building standard (nZEB) will be obligatory for all new buildings by 2021. Although the increase in energy demand will be reduced with this measure, it does not really affect the energy consumption at present. It is imperative to design energy efficiency retrofit and renovation financing schemes. For many years to come, only measures taken in existing buildings will have a significant effect on the total energy demand in the building stock. Firstly, this work presents a brief analysis of active and passive solutions for an energy-efficient building. Secondly, in this work it identified a set of active and passive solutions, which, in a combined way, develop the thermal performance of a residential building, allowing it to become energetically autonomous. The program EnergyPlus was used to execute the thermo-energetic simulations for the diverse scenarios considered, in the study case. The numerical results showed that the implementation of passive solutions improves the energy performance of the buildings, and the use simultaneously of an active solution, a renewable energy source, allows the reach of the energy-autonomous of the building.

Evaluation of energy-saving retrofit projects of existing rural residential envelope structures from the perspective of rural residents: the Chinese case.

The existing residential envelope in rural areas has low energy efficiency, with low energy utilization and serious energy waste for winter heating. However, in recent years, farmers have not undertaken energy efficiency retrofit projects for existing buildings in rural areas. This study proposed an evaluation model based on the logistic-AHP-TOPSIS method from the perspective of farmers. First, this study conducted a questionnaire survey of 208 rural households and used logistic models to determine which existing evaluation indicators significantly impact farmers' willingness to participate in energy efficiency retrofit projects. Second, the weights of the eight indicators were determined using AHP. Finally, this study evaluated the retrofit program of a case in Gansu Province using the TOPSIS method. In the analysis, total investment, annual winter heating costs and energy efficiency improvements were found to be the most important factors for farmers. The highest score for existing buildings was 0.3747 because there is no additional investment required; the option of partial retrofitting according to the actual needs of households scored 0.3350 because it balances economic performance with energy efficiency performance; The entire retrofit program has the highest investment and a long payback period, and its score is the lowest with 0.2904. Furthermore, the study recommended that a self-build and self-repair organization led by village collectives be developed to unify the retrofit design and construction and lower renovation costs. Bulk purchases could enable farmers to increase their power in negotiations.

Potential and roadmap of CO2 emission reduction in urban buildings: Case study of Shenzhen

Buildings play an increasingly important role to determine the trend of CO2 emissions in cities. Whether CO2 emissions from buildings can be effectively mitigated has great significance for cities to achieve climate governance goals. The study takes Shenzhen, a China's megacity, as an example to examine how the penetration of newly emerging clean technologies and consumer-to-prosumer role transition of buildings will contribute to CO2 emission reductions. Based on a Low Emissions Analysis Platform (LEAP) model, the major results indicate that CO2 emissions of Shenzhen's building sector could be capped by 2022–2025 and substantially decreased by more than 60% by 2030. Accelerating energy efficiency retrofitting of existing buildings and enforcing stricter design standards on new buildings could largely reduce CO2 emissions, but still unable to prevent them from growing. The intensification of building energy-saving management and promotion of distributed renewable energy use would bring additional potentials of emission reduction, enabling a peak-reaching and a rapid downward trend of building emissions. To achieve the potentials, close cooperation and synergic efforts between multiple stakeholders are advocated for establishing intelligent energy-saving management systems, decarbonizing urban power supply, and popularizing distributed rooftop photovoltaic power stations.

Interaction of rigid shallow foundation with dip-slip normal fault rupture outcrop: effective parameters and retrofitting strategies

Devastating influences of fault rupture outcrop on various geo-structures during past earthquakes have revealed the necessity of more detailed and comprehensive studies on the fault-foundation interaction. In this study, the interaction between the normal fault and shallow surface/embedded strip foundations is rigorously examined through a well-established upper bound limit analysis formulation in conjunction with the finite element discretization and linear programming technique. The adopted upper bound FELA method is shown to be efficient and cost-effective with high predictive capability, which can be easily implemented in any common computational platforms, like MATLAB. The accuracy of the adopted numerical method is first verified against some findings in the literature. Using this validated numerical approach, a comprehensive parametric study is performed to examine the interaction of the normal fault rupture outcrop with the surface and embedded shallow foundations. Accordingly, the influences of various parameters including the foundation breadth, the service footing pressure, the internal friction angle of the soil deposit, the foundation embedment depth, the fault throw and the relative distance between the fault rupture and shallow foundation, on the normal fault-footing interaction are systematically investigated and discussed. In addition, as an efficient retrofitting strategy to protect the shallow foundation against the fault outcrop, rigid mitigating barrier walls with different filling materials are proposed so as to divert the mainstream of the fault rupture and thus reduce its destructive effects on the overlying superstructures. In this regard, another parametric survey is carried out to explore the effects of wall-related geometric parameters, such as its depth, width, filling material and relative position, on the reduction of the destructive consequences of the normal fault rupture emergence at the ground surface. The results generally show that applying a rigid concrete wall with suitable height, width and distance from the foundation leads to the significant reduction in the amount of surface footing rotation subjected to normal fault rupture outcrop.