Density and morphology: from the building scale to the city scale

The density of the domestic building stock of London is explored, moving from the scale of individual house and blocks of flats, through larger geographical units, to complete boroughs. The description of the stock is highly detailed and is made using the 3DStock method, which derives building geometry from digital maps and LiDAR (laser measurements from overflying aircraft). This means that accurate estimates of floor areas can be made and used to measure densities as Floor Space Index (FSI) values. Ground coverage or Ground Space Index (GSI) values are calculated from building footprints and land boundaries. The Spacemate tool, devised by Berghauser Pont and Haupt, is used to plot the types and ages of dwellings in terms of FSI, GSI and numbers of storeys. Figures for actual annual gas and electricity consumption are attached to each dwelling. Analysis shows that, in general, energy-use intensities—and especially the intensity of gas use for heating—decrease with increasing density, and with the transition between house types, from detached, to semi-detached, to terraces, to (low-rise) flats

Using Display Energy Certificates to quantify public sector office energy consumption

This paper explores how internal and external characteristics affect energy use in the public sector office stock in England and Wales, using a database of 2,600 Display Energy Certificates (DECs) combined with other sources of disaggregated office information. The DEC office benchmarks were shown to match the median fossil thermal and electrical consumptions well. Analysis of HVAC, size, occupancy density, building age, location and rateable value were considered. While newer offices were shown to have lower typical fossil-thermal consumption than older offices, this was counterbalanced by higher electrical consumption, resulting in higher typical CO2 emissions. This has implications for the UK's emissions reduction targets for 2050, indicating that while building regulations that focus on thermal performance have been successful, a focus on electrical consumption (both regulated and unregulated) is key. The results were also compared with existing benchmarks for all UK offices, splitting the sample into four generic types, and compared to a similar smaller study of private offices. This indicated that public offices typically used less energy than the general benchmarks had previously predicted, particularly for prestige offices.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) funding for Doctoral Training Studentships, and in association with the EPSRC funded 'ReVISIONS' project [grant number EP/F007566/1].This is the final published version. It first appeared at http://dx.doi.org/10.1080/09613218.2014.97541

A high temporal resolution assessment of photovoltaic electricity production and energy consumption of an electrified London primary school

In line with the UK goal to reach carbon neutrality by 2050, the combination of photovoltaic electricity and the electrification of heating systems is considered an effective way to reduce greenhouse gas emissions, while 88% of schools in the UK are gas-heated. This paper analyses the electricity consumption at a 15 and 30min resolution of different scenarios for the retrofitting of a primary school in London, UK, with an electrified heating system and the electricity production of different PV installations. Without a battery storage, thanks to high temporal resolution assessment, only 35 to 47% of the school energy consumption can be met. High temporal resolution allows consideration of to economic balances and the possibilities PV can have on decarbonizing heating systems in UK primary schools

Temporal resolution of photovoltaic electricity production with school energy consumption: a London primary school case study

In line with the UK goal to reach carbon neutrality by 2050, the combination of photovoltaic electricity and the electrification of heating systems is considered an effective way to reduce greenhouse gas emissions, while 88% of schools in the UK are gas-heated. This paper analyses the electricity consumption at a 15 and 30 min resolution of different scenarios for the retrofitting of a primary school in London, UK, with an electrified heating system and the electricity production of different PV installations. High temporal resolution allows consideration of economic balances, in light of rising costs of energy in the UK in 2022, and the possibilities PV can have on decarbonizing heating systems in UK primary schools. Practical application - The high temporal resolution allows to provide a project economic balance with close to reality figures. It also allows schools to rely on energy produced on site with less price fluctuation and to have the educational benefit of the PV installation. The high temporal resolution also provides data on what types of activities are the most energy consuming and can inform behaviour/time schedules changes

Energy use and height in office buildings

The relationship between energy use and height is examined for a sample of 611 office buildings in England and Wales using actual annual metered consumption of electricity and fossil fuels. The buildings are of different ages; they have different construction characteristics and methods of heating and ventilation; and they include both public and commercial offices. When rising from five storeys and below to 21 storeys and above, the mean intensity of electricity and fossil fuel use increases by 137% and 42% respectively, and mean carbon emissions are more than doubled. A multivariate regression model is used to interpret the contributions of building characteristics and other factors to this result. Air-conditioning is important, but a trend of increased energy use with height is also found in naturally ventilated buildings. Newer buildings are not in general more efficient: the intensity of electricity use is greater in offices built in recent decades, without a compensating decrease in fossil fuel use. The evidence suggests it is likely – although not proven – that much of the increase in energy use with height is due to the greater exposure of taller buildings to lower temperatures, stronger winds and more solar gains

All the way to the top! The energy implications of building tall cities

Density of urban form may be achieved under a variety of morphological designs that do not rely on tallness alone. Tall buildings have implications on the broader urban environment and infrastructure that lower buildings would not have, e.g. wind effects, sight-lines, or over-shading. They may also have an impact on energy use for reasons of buildings-physics, construction, and occupant practices. This study uses a statistical approach of neighbourhood level data to analyse the impact of building morphology (e.g. height, volume and density) on energy demand in 12 local authorities in London. The research shows that areas marked by tall buildings use more gas after adjusting for exposures surface area, volume, number of residents and other features. The implication for energy policy and planning is building taller without increasing density may have an energy penalty

Characterising the English school stock using a unified national on-site survey and energy database

The recent commitment towards a net-zero target by 2050 will require considerable improvement to the UK’s building stock. Accounting for over 10% of the services energy consumption of the United Kingdom, the education sector will play an important role. This study aims to improve the understanding of English primary and secondary schools, using national on-site survey data with several large-scale disaggregate data sources. Property Data Survey Programme (PDSP) data on 18,970 schools collected between 2012 and 2014, Display Energy Certificate (DEC) and school census data from the same period were linked and processed to form a unified schools dataset. Statistical analyses were undertaken on 10,392 schools, with a focus on energy performance, and the relationship to several building and system characteristics. The analyses may point to the possibility of assessing operational energy use of schools in a more disaggregate manner. New datasets with detailed and accurate disaggregate information on characteristics of buildings, such as those used in this study, provide opportunities to develop more robust models of the building stock. Such data would provide an opportunity to identify pathways for reducing carbon emissions effectively and provide lessons for other organisations seeking to achieve significant reductions for achieving climate change goals

Getting to net zero: Islington’s social housing stock

This paper describes the development of a detailed plan to get the social housing stock of the Borough of Islington in London, UK, to net zero carbon emissions. This stock is very diverse in form, age and construction, and includes houses, flats and maisonettes. A total of 4500 buildings containing some 33,300 dwellings were modelled using the 3DStock method. Six packages of measures combining fabric improvements, heat pumps and photovoltaic installations were evaluated for each dwelling individually, in terms of costs, the impacts on gas and electricity use, and predicted cuts in carbon emissions. The rollout of measures between 2020 and 2030 was modelled with a specially developed scenario tool, allowing the user to set different criteria and priorities. Fabric measures on their own were shown to achieve only a 13% cut in gas use on average. Heat pumps are the key to displacing gas use. With all measures combined and taking account of the predicted decarbonisation of the electricity supply, it is only possible to achieve an overall 70% cut in emissions by 2030. Policy relevance The development of a detailed practical plan of action is described: an applied case study with the close engagement of the local authority—not a theoretical desk exercise. Each dwelling in Islington’s housing stock was examined and measured separately. The modelling did not rely on ‘archetypes’ as in many such studies. Realistic retrofit options were analysed in each case, using current cost data from practitioners. The same approach could be applied directly to other London boroughs, and for local authorities outside the capital, although different costs and other local factors would apply. For readers outside the UK, the methodology and tools could serve as exemplars. The findings about the respective contributions of heat pumps, solar photovoltaics and fabric measures, and the effects of different priorities in the rollout of retrofits, have relevance for policymaking more generally at local and national levels

Window operation behaviour and indoor air quality during lockdown: A monitoring-based simulation-assisted study in London

The Covid-19 outbreak has resulted in new patterns of home occupancy, the implications of which for indoor air quality (IAQ) and energy use are not well-known. In this context, the present study investigates 8 flats in London to uncover if during a lockdown, (a) IAQ in the monitored flats deteriorated, (b) the patterns of window operation by occupants changed, and (c) more effective ventilation patterns could enhance IAQ without significant increases in heating energy demand. To this end, one-year’s worth of monitored data on indoor and outdoor environment along with occupant use of windows has been used to analyse the impact of lockdown on IAQ and infer probabilistic models of window operation behaviour. Moreover, using on-site CO2 data, monitored occupancy and operation of windows, the team has calibrated a thermal performance model of one of the flats to investigate the implications of alternative ventilation strategies. The results suggest that despite the extended occupancy during lockdown, occupants relied less on natural ventilation, which led to an increase of median CO2 concentration by up to 300 ppm. However, simple natural ventilation patterns or use of mechanical ventilation with heat recovery proves to be very effective to maintain acceptable IAQ

Indoor air quality during lockdown: A monitoring-based simulation-assisted study in London

The Covid-19 outbreak has resulted in new patterns of home occupancy, the implications of which for indoor air quality (IAQ) and energy use are not well-known. In this context, the present study investigates 8 flats in London to uncover if during a lockdown, (a) IAQ in the monitored flats deteriorated, (b) the patterns of window operation by occupants changed, and (c) more effective ventilation patterns could enhance IAQ without significant increases in heating energy demand. To this end, one-year’s worth of monitored data on indoor and outdoor environment along with occupant use of windows has been used to analyse the impact of lockdown on IAQ. Moreover, using on-site CO2 data, monitored occupancy and operation of windows, the team has calibrated a thermal performance model of one of the flats to investigate the implications of alternative ventilation strategies. The results suggest that despite the extended occupancy during lockdown, occupants relied less on natural ventilation, which led to significantly higher CO2 and PM10 concentrations. However, simple natural ventilation patterns or use of mechanical ventilation with heat recovery proves to be very effective to maintain acceptable IA