Urban Albedo Computation in High Latitude Locations: An Experimental Approach

Lead Research Organisation: University of Kent
Department Name: Kent Sch of Architecture

Abstract

The proposed research will develop a novel experimental and modelling study for the computation of urban albedo in high latitude locations, using London as a representative urban environment in the UK. This work is primarily motivated by the need to provide accurate albedo estimates for urban configurations, as such calculations are lacking in most Urban Heat Island (UHI) models used to mitigate its effects.

The research will investigate the seasonal effects of albedo on urban temperature. Albedo intervention can bring substantial positive effects during the summer while marginal negative effects are expected in winter. In mild climates such a negative effect might out-weigh summer benefits. It is possible that seasonal intervention on the urban fabric could give an overall positive impact but for this, accurate computation of urban albedo is required at urban design or intervention stage. These issues will be investigated in the proposed study which has three aims; (a) to investigate experimentally the impact of urban fabric on urban albedo; (b) to develop a catalogue of urban albedo for various material and geometrical combinations and (c) to develop an empirical model to predict changes in urban albedo in relation to changes in urban fabric and solar altitude with a specific focus on advanced materials. This aim will be achieved through an extensive experimental study that includes field and laboratory scale measurements, computer modelling, and followed by the development of an urban albedo calculator that is able to explore seasonal variations. The Urban Albedo Calculator values could be used to predict the urban heat island with greater confidence.

Planned Impact

The urban albedo project will lead to a step-change advancement in the understanding of the photometric phenomena of urban surfaces in the context of complex urban geometries. The research will have an impact on UK policy makers in DBEIS, DCLG, DEFRA, GLA and in many local authorities. The policy makers in these organisations can develop urban environment related guidelines that have an impact on façade characteristics more confidently, especially guide lines to mitigate the UHI. Advanced knowledge of urban albedo will lead to better management of UHI. The research will help designers to ensure that new and refurbished façades will have a low impact on outdoor overheating in the summer, which is likely to become more prevalent with future climate change. Planning, urban design, architecture, civil engineering and environmental practices could use the research findings as well as the urban albedo calculator in their day to day consultancy work. Planners and designers could use the urban albedo values from the catalogue to evaluate alternative schemes at early stages. Currently, planners and designers on most occasions carry out urban albedo evaluations based on subjective judgement. Overall the urban albedo calculator will reduce the uncertainties associated with reflective radiation in predicting urban heat island intensity (UHII) and building energy performance. Public understanding of the impact of infrared radiation in the urban environment will be enhanced, through the involvement of school children with the experiments, inspiring students to study STEM subjects. The findings could point the façade material manufacturers towards new directions especially in terms of high urban albedo materials. Further, manufacturers could test these products in different urban geometries using the Urban Albedo Calculator, as well as through the test site which will be set up at University of Kent. Developers of free-ware software focusing on urban climate will have opportunity to integrate the Urban Albedo Calculator into their model.

Publications

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Description CIBSE Resilient Cities Special Interest Group 
Organisation Chartered Institution of Building Services Engineers (CIBSE)
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Given the interest of the CIBSE Resilient Cities Group on the importance of urban form and characteristics on the energy and thermal performance of buildings, the potential advances the project will make on better characterisation of urban albedo on urban microclimate and implications for overheating of urban buildings and the development of modelling tools will be relevant.
Collaborator Contribution CIBSE has worked with us in meetings and workshops to inform the development of the project
Impact The collaboration has supported the development of an important workshop on 'Urban Albedo: Digital tools for urban resilience and growth' (October 2018) which reached different audiences and informed the development of the project. Eventually, CIBSE will be able to publish the key results from the project, incorporating guidance material arising from the project into their publications.
Start Year 2017
 
Description Ibstock-Brick supplies for development of 1:10 models 
Organisation Ibstock Brick Limited
Country United Kingdom 
Sector Private 
PI Contribution As clay bricks account for over 50% of all the facades built in the UK today our project is of interest to Ibstock; particularly (i) identifying the role of brick materials on urban albedo, (ii) ways to characterise the materials for inclusion in an Urban Albedo Calculator, and (iii) inclusion of bricks in a catalogue of urban albedo for various materials and geometrical configurations
Collaborator Contribution Brick materials for developing the 3D 1:10 scale model of areas of London, to be used for testing and experimentation in calculating urban albedo of real sites. This was essential to be able to study the material in urban developments.
Impact The bricks have been used for buidling the models. The monitoring work is ongoing and the results from the experiments pending.
Start Year 2017
 
Description 'Urban Albedo: Digital tools for urban resilience and growth' workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The project team along with the Greater London Authority and the London Climate Change Partnership (LCCP) organised a very successful workshop at London's Living Room, City Hall on Monday 15th October 2018, marking the beginning of Green GB week. The workshop 'Urban Albedo: Digital tools for urban resilience and growth', which was chaired by the former President of the Urban Design Group, Colin Pullan, brought together leading urban and building scientists, as well as practitioners from different backgrounds, to inform the impact of urban morphology and materials on urban albedo and its importance for health and well-being.
The presentations from the speakers included:
- Urban albedo - state of knowledge and project overview - Prof. Marialena Nikolopoulou, University of Kent
- London's heat risk in a changing climate - Kristen Guida, LCCP
- Insights from practice panel:
The Concrete Centre (Guy Thompson)
Fosters + Partners (Stefano Capra)
SWECO (Gabriela Costa)
IESVE (Dr Khan Naghman)
CIBSE Resilient Cities (Dr Anastasia Mylona)
Year(s) Of Engagement Activity 2018
URL https://research.kent.ac.uk/urbanalbedo/news-and-meetings/workshop-1-importance-of-urban-albedo-the-...
 
Description MSc dissertations 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact Educational - Three MSc dissertations on different aspects of urban albedo
Year(s) Of Engagement Activity 2017,2018
 
Description Stakeholder Engagement Planning Workshop 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact An intensive workshop with ARCC/Space4Climate and LCCP on developing extended communication and engagement pathways to help enhance and broaden the pathways to impact work for the project.
Year(s) Of Engagement Activity 2018
URL https://research.kent.ac.uk/urbanalbedo/news-and-meetings/