Rajat Gupta

Oxford Brookes University · School of Architecture

Indian residential energy consumption increased nearly 50 times its levels in 1971. Studies have reported a wide variation between the statistically projected and actual energy consumption values in residential buildings. Access to reliable energy consumption data is limited in Indian cities. This study aims to use primary datasets to develop a bas...

Indoor air quality (IAQ) in residences is a complex phenomenon determined by many factors. IAQ in homes has been studied far less than air quality outdoors, especially in urban India, where outdoor air pollution frequently exceeds recommended levels. This paper empirically examines daily trends and variations in IAQ parameters measured across a sam...

Local Smart Grids (LSGs) are emerging during the climate crisis, as governments and industry recognize the need to better integrate intermittent renewable energy, storage, transportation, heating, and smart technologies. Such projects can represent profound changes to the status quo of energy and citizen lifestyles. They are also being associated w...

We evaluate current and future summertime temperature and indoor air quality (IAQ) in two London care homes, occupied by seniors. We further examine the effect of natural ventilation, aiming to identify strategies that can maintain temperature, CO 2 and key pollutants (PM 2.5 , NO 2 ) within acceptable ranges. Data come from simulations in DesignBu...

The UK government has announced its ten-point plan to annually install 600,000 low-carbon heat pumps by 2028. However, there is a lack of evidence showing potential overheating risk in dwellings retrofitted with heat pumps. This paper examines the prevalence and magnitude of summertime overheating across 24 naturally ventilated social housing dwell...

To meet UK government targets of 22% reduction in greenhouse gas emissions (1990–2035), large scale retrofit of the existing housing stock is necessary. This paper empirically investigates the performance of a low-rise block of flats pre- and post-retrofit. Pre-retrofit findings informed retrofit design, and provided a benchmark for post-retrofit p...

India is among the top five countries in the world for green buildings. However, data on actual energy performance and occupant satisfaction in these buildings are lacking. This paper seeks to apply a customised post-occupancy building performance evaluation approach for Indian green buildings (I-BPE), to evaluate the actual performance of two gree...

Wintertime electricity use in India has received little attention due to the growth of residential air conditioning (AC) in the summer and monsoon seasons. This paper combines monitoring (time-series) and survey (contextual) data to examine the wintertime pattern of daily electricity current, indoor temperature, and relative humidity profiles acros...

Deploying smart local energy engagement tools (SLEETs) in local energy projects enables users to better observe and control energy, and potentially become active participants in local energy management. Using a cross-project approach, this paper examines the prevalence, effectiveness and inclusiveness of 84 SLEETs deployed in 72 local energy projec...

The residential sector accounts for around 24% of the total electricity consumption in India. Recent studies show that air conditioners (ACs) have become a significant contributor to residential electricity consumption. Further, it is predicted that by 2037, the demand for ACs will increase by four times due to their affordability and availability....

Air Conditioners (ACs) have become a major contributor to residential electricity consumption in India. Non-intrusive Load Monitoring (NILM) can be used to understand residential AC use and its contribution to electricity consumption. NILM techniques use ground truth information along with meter readings to train disaggregation algorithms. There ar...

Low carbon technologies along with smart control have a role in residential demand side response (DSR) to shift the timing of household energy consumption away from peak times and align it with generation of renewable electricity. This paper empirically evaluates the impact of DSR trials on grid electricity import and resident experience regarding...

Oversimplifying occupant behaviour using static and standard schedules has been identified as a limitation of building energy simulation tools. This paper describes the use of hierarchical cluster analysis to establish the most typical indoor temperature profiles of Albanian dwellings based on monitored indoor temperatures in winter and summer, alo...

This study evaluated the actual environmental behaviours in an eco-development case study in the UK, which was designed to enable more sustainable lifestyles. Data analysis was based on the resident responses to a development-wide questionnaire survey (n = 89), household interviews (n = 12) and waste measurements. Reported energy- and water-saving...

Smart thermostats allow continuous learning, remote scheduling and control of indoor temperature. This paper empirically evaluates indoor environmental conditions, occupant experiences and prevalence of summertime overheating in three low-energy dwellings with smart thermostats and compares the results with three similar dwellings with standard pro...

Smart control technologies are beginning to be deployed in homes to optimise heating and alter the timing of domestic energy demand to enable residential demand side response (DSR). This paper presents before (baseline phase) and after (control phase) evaluation of the monitored indoor temperature and energy demand during the heating season in 10 n...

Residential electricity consumption (REC) in India has tripled in the past two decades accounting for 24% of the overall electricity consumption during 2018-19. Residential air conditioning (AC) usage is responsible for about 20%-40% of REC in India. This paper investigates the relationship of residential AC use with indoor temperature and relative...

The first wave of COVID-19 pandemic led to a nationwide lockdown in India from 25th March to 30th May 2020. This study examines the change in residential electricity consumption, use of air conditioning (AC) and well-being of residents during the lockdown period when normal activities became home-based and travelling was curtailed. An online househ...

As governments worldwide address the climate crisis, energy systems are becoming both decarbonised and decentralised. In this study, we aim to increase understanding of the spatial dimensions of new forms of decentralised energy systems that integrate electricity, storage, transportation, and heating. Drawing on workshops and secondary data from th...

A Practical Guide to Climate-resilient Buildings & Communities offers construction solutions to adapt to a range of different risks in various climates. For instance, it shows us how to reduce indoor heat in hot and arid climates, or how to mitigate cyclone impacts on buildings in hot and humid climates. Importantly, the report also provides us wit...

The warming climate causes adverse effects on thermal comfort and health, especially for vulnerable older adults. This study assesses the current and future risk of summertime overheating in London’s care homes and explores the potential of passive ventilation on reducing these risks. Analysis is based on temperature monitoring of two care settings...

Residential electricity consumption (REC) in India has tripled in the past two decades accounting for 24% of the overall electricity consumption during 2018-19. Residential air conditioning (AC) usage is a one of the largest contributors of REC. This paper investigates the relationship of residential AC use with indoor temperature and relative humi...

Summertime overheating in care settings has been identified as a key risk and research priority for the health and social care system. This paper examines the current and future risk of summertime overheating in two London-based care homes occupying modern and older buildings. Continuous monitoring of outdoor and indoor temperature in bedrooms, com...

This paper systematically examines the in-use energy and carbon performance of a large case study housing development in England, designed to be net true zero carbon. Remote monitoring during a one-year period was used to gather high-frequency data on dwelling heat use, grid electricity use, solar PV electricity generation and export and community...

This paper brings together objective and subjective data on indoor temperature and thermal comfort to examine the magnitude and perception of summertime overheating in two London-based care homes occupying modern and older buildings. Continuous monitoring of indoor and outdoor temperature, relative humidity and CO 2 levels was conducted in summer 2...

To bridge the growing housing shortage, India plans to construct 10 million dwellings under the ‘Housing for All by 2022’ initiative. Since housing is responsible for 22% of the country’s energy consumption (in 2014), it is integral to ensure that the new housing stock reduces the need for energy-intensive air conditioning. This paper assesses the...

Empirical assessment of sociotechnical factors that influence residential electricity use in India

This paper presents the methodology and results of in situ testing of building fabric thermal performance to calibrate as-built energy models of three low-energy dwellings in the UK, so as to examine the gap between as-designed and as-built energy performance. The in situ tests included repeat testing of air permeability (AP) integrated with therma...

We explore methodological issues core to the cost-benefit evaluation of building adaptations designed to protect against heat risks to residents of care homes in England in the context of the uncertainties relating to the loss of life expectancy in heat death. We used building physics modelling to quantify the impact of external window shading on i...

As part of the EBC Annex 80 - Resilient cooling of buildings activities, the Thermal Condition Taskforce was created, in April 2020. In coordination with all other groups and the Weather Data Taskforce, two objectives were set by the Annex leader Dr. Peter Holzer. Firstly, to define common thermal conditions to assess different cooling technologies...

A long-standing challenge for area-based mass retrofits has been the ability to rapidly and accurately target appropriate dwellings for energy improvements. This paper demonstrates the application of a data-driven localised Geographical Information System (GIS)-based domestic energy mapping approach to create house-by-house baseline energy models a...

Measurement and verification (M&V) has become necessary for ensuring intended design performance. Currently, M&V procedures and calculation methods exist for the assessment of Energy Conservation Measures (ECM) for existing buildings, with a focus on reliable baseline model creation and savings estimation, as well as for reducing the computation ti...

In-situ testing of actual building performance is vital to achieve the UN Sustainable Development Goal 11 (Sustainable cities and communities) in reality, given the growing concern that low energy dwellings often underperform against design specifications. This paper presents the methodology and results of in-situ measurements of the building fabri...

Smart local energy systems (SLES) can intelligently and locally link energy supply, storage and use, and power, heating and transport in ways that dramatically improve efficiency. This paper undertakes a meta-study of the technologies deployed, leadership and extent of user engagement achieved in SLES initiatives undertaken in the UK from 2009-2018...

There has been increasing recognition that climate change may lead to risk of summertime overheating in UK dwellings with potentially adverse consequences for human comfort and health. This paper investigates the magnitude of summertime overheating over one month in 2017, in four new flats built to identical thermal standards, with similar occupanc...

This pilot study aims at testing methods to assess heat vulnerability in London care homes and develop overheating reduction strategies to mitigate temperature exposure and the associated negative health impacts under the warming climate, with a view to scaling up the project on a national scale. It undertakes feasibility work to identify possible...

This paper uses a case study-based approach to comparatively evaluate the relationship between measured and perceived indoor environmental conditions in two office buildings, one naturally ventilated and one mechanically ventilated, located in south England. Environmental parameters (indoor and outdoor temperature and relative humidity, and indoor...

The Sustainable Development Goal - House or SDG-House is a joint effort by UN-Habitat and its partners to encompass the important and novel breakthroughs in areas related to the sustainability of the Housing Sector. The approach recognises that the housing sector is complex, and touches on many socio-economic, environmental, and cultural aspects of...

This paper presents the systematic review on thermal comfort studies in Indian residential buildings, helpful in identifying the present research scenario, data gaps and policy interventions. Majority of the studies are performed in composite climate (ten), followed by warm-humid (seven) and a very few from cold (two) and hot-dry (two) climates. No...

Residential energy (electricity) use in India is expected to grow four-fold by 2030, yet there is paucity of data that is essential for developing energy policy or programme. This paper undertakes a meta-study of residential energy studies in India to characterise their scope, data collection methods and findings. An in-depth review of literature w...

Most studies linking indoor environments and productivity have been conducted in controlled, static conditions often unrepresentative of the real world. This paper uses a case-study-based, real-world approach to empirically investigate the link between indoor environment and workplace productivity in a mechanically-ventilated office environment in...

This paper uses a case study-based approach to empirically investigate the relationship between indoor environment and workplace productivity in two contrasting office environments: one naturally ventilated, the other mechanically ventilated. Environmental parameters were continuously monitored over 19 months. Transverse and longitudinal surveys re...

This paper uses a case study-based approach to comparatively evaluate the relationship between measured and perceived indoor environmental conditions in two office buildings, one naturally ventilated (NV) and one mechanically ventilated (MV) located in southeast England. Environmental parameters (indoor and outdoor relative humidity (RH), CO 2 and...

This paper applies a customised post-occupancy building performance evaluation (BPE) approach to evaluate the actual performance of a Platinum-certified green office building in the extreme hot dry climate of India from both technical and occupants’ perspectives. The in-use energy and environmental performance of the office building was examined us...

Purpose The field of building performance evaluation (BPE) forms a fragmented whole with tools and methods that are not widely applicable. In response, the purpose of this paper is to develop and demonstrate a novel BPE framework to bring consistency and flexibility in evaluating actual building performance. Design/methodology/approach The paper c...

This paper presents the results of a meta-analysis of hourly indoor summertime temperature datasets gathered during the summer of 2013 (May to September), from 63 dwellings, located across the UK. The sample consisted of unmodified dwellings (existing); dwellings with varying levels of fabric improvements (retrofitted) and dwellings constructed to...

This paper empirically evaluates the extent of energy resilience achieved in a socially-deprived community in Oxford, through deployment of solar photovoltaic (PV) systems and smart batteries (internet enabled and controllable) across a cluster of 82 dwellings (households). The methodological approach comprised dwelling and household surveys, along...

The green building movement in India is lacking an important link: ensuring that the design intent of such buildings is actually realized. This paper undertakes an exploratory investigation to develop and test a customized building performance evaluation (BPE) approach (I-BPE framework) for the Indian context. As academia is considered to be an ini...

This paper uses a real-world socio-technical building performance evaluation (BPE) approach to investigate the influence of physical factors (form, orientation) and occupant factors (number of occupants, occupancy pattern, heating schedule) on gas and electricity use (during the heating period) of four new-built modern flats located in the same hou...

This paper presents new evidence from a nationwide cross-project meta-study investigating the magnitude and extent of the difference between designed and measured thermal performance of the building fabric of 188 low energy dwellings in the UK. The dataset was drawn from the UK Government's national Building Performance Evaluation programme, and co...

This paper empirically investigates the influence of building fabric, services and occupant related factors on actual energy use of six case study dwellings, located in three new low energy social housing developments in UK, covering a variety of built forms and construction systems (timber frame, hempcrete, steel-frame). Physical monitoring of ind...

Vertical Axis Wind Turbine (VAWT) is a viable proposition for small-scale uses like, rural electrification, pumping, desalinating, household applications etc in many developing countries including India. In this paper, a hybrid neuro-fuzzy controller has been developed using gradient-based training algorithm to evaluate the performance of a combine...

This paper presents the methodological approach and findings of a simulation study of advanced energy conservation, generation and management technologies applied to two case study dwellings in the UK, so as to achieve net zero energy (NZE) target that includes a reduction of net regulated energy (HVAC) to 0 kWh/m2 per year and energy generation of...

The research activities described in this paper focus on the development and implementation of a comprehensive and cost-effective system for Net Zero Energy (NZE) settlements. The system is composed of innovative solutions for the building envelope, for building energy generation, and for energy management at the settlement level. The developed sol...

City authorities, community groups and retrofit installers need to identify suitable local areas and dwellings for installing energy retrofit measures. This paper presents a localised Geographical Information System (GIS) based approach that utilizes publicly-available national and local datasets on housing and energy to provide targeted low carbon...

Climate change makes many challenges on suburban areas. This chapter focuses on one of the multiple problematics of climate change: the challenge of overheating. Reporting on evidence from the EPSRC-funded SNACC project (EP/G061289/1), the chapter presents results from neighbourhood modelling of potential overheating in six English neighbourhoods u...

Most research to date on the provision of energy feedback to households has focused on assessing the efficacy of numeric-based feedback. This paper describes the application and evaluation of more visual energy feedback techniques (carbon mapping, thermal imaging) at different scales, alongside traditional methods (web-based energy and environmenta...

This paper uses a forensic building performance evaluation approach to undertake a comparative evaluation of the in-use energy and environmental performance data (collected over two years) of two civic buildings located in Southeast England – a small community centre (<1000 m²) and a medium-sized public library building (∼4500 m²), which are design...

The impact of a warming climate has serious implications for the elderly as they are especially vulnerable to negative health effects of excessive heat. This paper uses a building simulation approach to examine the current and future risk of summertime overheating and potential adaptive response of four care and extra-care settings representing dif...

There is an urgent need to improve the energy performance of the built environment, so as to help alleviate fuel poverty, meet national carbon targets, and improve the local economy. This is why local authorities have targets to reduce carbon emissions and fuel poverty and to create long-term, high-quality jobs in their areas. Large-scale energy re...

Research in UK and elsewhere has highlighted that older people are particularly vulnerable to negative health effects of overheating. This paper examines the magnitude, causes, preparedness and remedies for addressing the risk of summertime overheating in four case study residential care and extra-care settings across the UK, spanning different bui...

Despite growing concerns about overheating, a lack of evidence exists on the scale of the problem, particularly in contemporary UK housing. This paper presents the results of a meta-analysis of indoor temperatures in selected low-energy housing. Temperature data recorded at five-minute intervals in 60 dwellings across 19 demonstration projects (201...

This paper uses a socio-technical building performance evaluation (BPE) approach to assess the pre- and post- actual performance of two discrete deep low energy retrofits in the UK – a Victorian solid-wall house and modern 1990s cavity-wall house. A ‘low-energy first, then low-carbon’ approach was adopted in both cases, to achieve an 80% reduction...

This paper presents a systematic, socio-technical and empirical evaluation of the actual energy and environmental performance of a sustainably-designed institutional building (Southeast England), intended to be a teaching tool and ‘living laboratory’ of sustainability. Despite the building being designed to high sustainability standards (Energy Per...

This meta-study was commissioned by Innovate UK as part of the Building Performance Evaluation (BPE) Programme to provide an overview of the performance and use of whole-house heat recovery ventilation (MVHR) systems in domestic projects. With increasing requirements for energy reduction, the impact of ventilation strategies has increased in import...

This meta-study was commissioned by Innovate UK as part of the Building Performance Evaluation (BPE) Programme to provide an overview of the performance and use of whole-house heat recovery ventilation (MVHR) systems in domestic projects. With increasing requirements for energy reduction, the impact of ventilation strategies has increased in import...

This meta-study was commissioned by Innovate UK as part of the Building Performance Evaluation (BPE) Programme to provide an overview of the performance and use of whole-house heat recovery ventilation (MVHR) systems in domestic projects. With increasing requirements for energy reduction, the impact of ventilation strategies has increased in import...

This paper uses a socio-technical building performance evaluation approach to forensically and systematically evaluate the actual performance of two case study dwellings located in a flagship eco-housing development in the UK, during the post-construction/initial occupation stage. The 12-month study captures the ‘as-built’ performance of the buildi...

This paper presents the findings from building performance evaluation studies of two deep retrofits in UK – Victorian house and Modern 1990s house. Both case studies were designed to achieve 17 kgCO2/m2/year (equivalent to 80% reduction) and adopted a fabric-first approach. Post-retrofit, it was found that the Victorian house achieved a 75% CO2 red...

The Retrofit for the Future programme, sponsored by UK government's Technology Strategy Board (TSB) from 2009 to 2013, demonstrated innovative approaches to deep retrofitting of social housing, using a whole-house approach for achieving an 80% CO2 reduction target. The intent and outcomes of this programme (in which all authors participated) are cr...

Infrastructure is a means to an end: it is built, maintained and expanded in order to enable the functioning of society. Present infrastructure operation is characterised by: governance based on unmanaged growing demand, which is both inefficient and ultimately unsustainable; lack of integration of the end-users, in terms of the variety of their wa...

This paper investigates the risk of projected post-2050s overheating in existing, retrofitted and new-build dwellings in the United Kingdom. As shown in the previous research, passive measures may not be sufficient in mitigating overheating risk. Therefore, mechanical cooling technologies that may be deployed to ‘adapt’ to a warming climate are tes...

New low-carbon houses are designed to reduce heat losses through improved airtightness and increased insulation, raising the risk of overheating and inadequate ventilation. This paper examines the overheating risks and indoor air quality (IAQ) of three sustainable social housing developments in England (UK), by conducting building performance monit...

Thermodynamic analysis of coal fired furnace attached to a vibro fluid bed dryer (VFBD) for hot air generation in the drying stage of tea processing installed in the Rosekandy tea estate factory, Cachar, Assam, India is studied with the application of the principles of energy and exergy analysis. The study explores that the process of obtaining hot...

This research study investigates the effects of the large-scale installation of domestic heat pumps on the UK electricity supply over the short to medium term. A BREDEM-based dwelling energy model, incorporating a model of heat pump performance, is enhanced for the effects of varying monthly temperatures. Data from the English Housing Survey (2007)...

Purpose – This paper aims to, using a systematic mixed-methods based monitoring and evaluation approach, investigate the unintended consequences of physical and technical home improvements on energy use, indoor environmental conditions and occupant behaviour in community-led retrofits. The study is part of a UK Research Council funded research proj...

E nergy is an essential ingredient in the socioeconomic development and economic growth of any country. Energy is available in two different forms, non-renewable (coal, fuel, natural gas) and renewable (solar, wind, hydro, wave). Wind energy is the most abundantly available clean form of renewable energy. The impetus for the continual harnessing of...

Community-led approaches have emerged in the UK as an alternative route for realizing reductions in domestic energy demand through changes in homeowners' understanding and behaviours when coupled with physical retrofitting. A socio-technical approach is used to develop and apply a monitoring and evaluation framework. This framework comprises assess...

Withering is the first processing step in the tea processing factory. For efficient tea processing, withering should be as uniform as possible. Uniformity in the trough withering greatly depends on the uniformity of the drying air temperature and velocity distribution along the trough. In literature no study is reported on thermal and velocity prof...

The majority of the English population lives in suburbs and this is where the impacts of climate change will significantly affect people's domestic lives: heat stress, respiratory problems, flooding, drought, deterioration of green spaces and damage from storms. A recognized need exists to adapt suburbs (homes, gardens and public space) physically...

Purpose This paper presents new research on the potential pathways for integrated adaptation that could make England's suburbs more resilient to future climate conditions. It focuses on the role of central government, local agencies and householders in making adaptations to the built and natural environment. Design/methodology This paper uses evid...

Purpose To critically compare three future weather year (FWY) downscaling approaches, based on the 2009 UK Climate Projections, used for climate change impact and adaptation analysis in building simulation software. Design/methodology/approach The validity of these FWYs is assessed through dynamic building simulation modelling to project future ov...

As the impacts of climate change become more prominent within the next 50 years and beyond, the risk of overheating in homes is a concern. This is specifically relevant in the UK's suburbs where 84% of the population reside. To assess this future impact and the effectiveness of adaptive retrofitting, probabilistic climate change data for the 2030s...