Numerical and experimental study on integrated strategic simulation model of urban environment

Lead Research Organisation: University of Reading
Department Name: Construction Management and Engineering

Abstract

The microclimate parameters in urban areas have important impacts on the energy performance of buildings and the potential of passive cooling measures. For example, the urban heat-island (UHI) effect results in increased local atmospheric and surface temperatures in urban areas compared to the surrounding rural areas. Thus, the UHI will increase the overheating risk and the peak cooling load of buildings. It may particularly have a negative impact on night cooling strategies within the UHI during periods of hot weather. Effective urban planning and building design can have a beneficial effect on the urban climate and contribute towards reducing the intensity of the urban heat island, which improves the conditions in living spaces as well as directly reducing the peak cooling load of a building. The vision of the proposed project is to develop a practical, robust, urban thermal simulation method by using Digital Element Model (DEM) to store urban building geometry and boundary information and integrating it with the coupled thermal and airflow model. The DEM is a compact way of storing 3D information using a 2D matrix of elevation values; each pixel represents building heights and can be displayed in a grey-shaded digital image, which has a grey-level proportional to the level of the urban surface. The DEM is capable to handle large amount of data in less time. It is also able to present the geometrical relations among the buildings in the studied area. It has been proven to be an effective way of urban analysis. This model will be used to perform parametric study for various configurations of urban form and texture, building and road surface materials and vegetation in order to analyse Urban Heat-Island (UHI) mitigation strategies and potential passive measures of energy-efficient buildings. The principal objectives of this proposed three-year project are: (1) To develop a dynamically coupled thermal and airflow urban model integrating with the Digital Element Model (DEM), and to validate the model in association with experimental investigations in the urban canyon; (2) To link the proposed numerical urban model with the existing thermal and airflow building model (developed by the PI) to conduct an analysis of the interrelationship of the urban microclimate and building energy performance; (3)To perform an urban parametric study and analyse the potential of UHI mitigation strategies and their impact on the urban environment and energy consumption (CO2 emission) and (4)To assess urban and building thermal comfort. The prospected deliverables are: D1: A coupled thermal and airflow urban dynamic model integrated with the Digital Element Model (DEM) together with a series of numerical and visualised simulation results of different urban configurations for urban environment analysis; D2: A integrated urban microclimatic and building energy simulation model; D3: A series of parametric assessments for the urban environment and the potential of UHI mitigation strategies and D4: A series of assessments for passive measures of energy-efficient building design in the urban context.
 
Description - the layout and configurations of buildings cause the variation of microclimate from one location to another;
- the evapotranspiration effects from vegetation can help to cool down the ambient air especially when there is a traffic heat source at present;
-the surrounding high-rise buildings can block the direct solar radiation, but at the same time may decrease the wind permeability.
- The combined effect should be considered case by case;
- the potential of solar energy in an urban area is determined mainly by the sky view factor and the orientation to the most intensive afternoon solar radiation. The less shelter from the neighbouring obstructions, the higher solar energy potential could achieve; and
- the wind potential in the urban area is significantly reduced due to the sheltering effects, but urban texture still plays a role.
-When the street axis is parallel to the wind direction, the most wind potential is attained; and the least normally occurs when the wind is perpendicular to the street axis.
The outcomes of this study reveal that the microclimatic parameters are significantly influenced by the attributes of urban textures and consequently, buildings within an urban area, are operating against their own individual microclimatic variables rather than the meteorological weather data. This underlines the need for a radical change towards considering the microclimate information for urban planning and building thermal and energy performance assessments. In addition, variation of wind speed, solar radiation and temperature in the studied urban area in London provides an exemplary case to demonstrate the importance of considering the microclimatic parameters in feasibility studies for implementation of renewable energy technologies in both design and policy making levels.
Exploitation Route The findings will help the master plan in terms of considering the urban forms; vegetation and mitigation urban heat island.
Sectors Construction,Education,Energy,Environment

 
Description Till now, over 22 citation web of science; 30 recorded from googlescholar; method has been used in Master design research in China and led to a new UK-CHina collaberative research 'Low carbon climate responsive heating and cooling solutions'.
First Year Of Impact 2018
Sector Construction,Energy,Environment
Impact Types Societal

 
Description CIBSE Guides
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description China Green Building Council Committee member
Geographic Reach Europe 
Policy Influence Type Membership of a guidance committee
 
Description Chongqing Green Building
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Gave evidence to a government review
Impact Provided evidence of Urban Heat Island in Chongqing to the government; Urban greenery strategy promoted by Chongqing Green Building Council; Outdoor thermal environment expected to be improved by mitigating overheating through vegetation.
 
Description Educational development /Book/Course
Geographic Reach Multiple continents/international 
Policy Influence Type Influenced training of practitioners or researchers
Impact * Book Chapter - Urban Microclimates and simulation in Yao Ed.(2013) Design and management of sustainable built environments, Springer. over 11,338 downloads in 2013 ranked top 25% most downloaded eBook on SpringerLink; * teaching materials for the new course Design and management of sustainable built environments.
 
Description China-UK Low Carbon Green Building and Eco-cites network, University of Reading
Amount £35,000 (GBP)
Organisation Chongqing University 
Sector Academic/University
Country China
Start 09/2011 
End 05/2014
 
Description Development of weather data for design by incorporating climate change scenarios and urban configurations
Amount £3,000 (GBP)
Funding ID Walker2012 
Organisation University of Reading 
Department Walker Institute for Climate Research
Sector Academic/University
Country United Kingdom
Start 03/2012 
End 08/2012
 
Description Progressing Eco-city Policies into Main-stream Practice
Amount £325,120 (GBP)
Funding ID SPF 
Organisation Foreign Commonwealth and Development Office (FCDO) 
Sector Public
Country United Kingdom
Start 06/2011 
End 06/2012
 
Description Urban Microclimates and Urban Heat Island in Chongqing, China
Amount £7,500 (GBP)
Funding ID 446 
Organisation Royal Institution of Chartered Surveyors 
Sector Academic/University
Country United Kingdom
Start 08/2011 
End 02/2013
 
Description China-UK Green Building and Eco-cites network 
Organisation Chongqing University
Country China 
Sector Academic/University 
PI Contribution The project aims to enhance the partnership between the UK universities ( Reading, Cambridge, Loughborough, Cardiff) and Chinese universities and research institutions in the field of sustainable built environment.
Collaborator Contribution The partners have been actively involved in collaboration in research and organisation of conferences.
Impact Joint organisation of international conference; Joint research application; Joint publications
Start Year 2011
 
Description Chongqing University Lohcool 
Organisation Chongqing University
Country China 
Sector Academic/University 
PI Contribution Setting up international collaborations in the low carbon cities area.
Collaborator Contribution Contribution to the modelling; Exploring case studies in Chongqing; Constitution to the publications
Impact A simplified mathematical model for urban microclimate simulation
Start Year 2008
 
Description Max Fordham LLP 
Organisation Max Fordham LLP
Country United Kingdom 
Sector Private 
PI Contribution Linking the collaboration between the academic and design practice
Collaborator Contribution Providing the need from design prospective; Contribution to the journal paper publication
Impact The Impact of Urban Wind Environments on Natural Ventilation
Start Year 2008
 
Description EPSRC Urban Microclimate project 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact Introduction of latest outcome from the project at the School Seminar in the University of Reading.

One of the Seminar Series organised by the School of Construction Management and Engineering at the University of Reading attended by both staff and students from the School, as well as by people from other Schools.

After the presentation, urban heat islands phenomena have been further understood.
Year(s) Of Engagement Activity 2012
 
Description Introduction of urban climate study at the University of Reading 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Updated research output from the project has been introduced to the colleagues including staff and student as well as architecture community in Cambridge.

One of the Seminar Series organised by the Martin Centre Research Seminar at the Department of Architecture attended by both staff and students from the Department, as well as by people from other Departments and the general Cambridge community.

After the talk, colleagues from the University of Cambridge expressed interests in collaborative research and publications.
Year(s) Of Engagement Activity 2010
 
Description Presentation: A tool of microclimates simulation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation to the company directors of RWDI, simulation consultant company.

A number of presentations and discussions were committed from May to December 2011 with RWDI in order to develop a KTP project.

After the presentation, the company decided to apply the KTP for further development of the tool.
Year(s) Of Engagement Activity 2011
 
Description Presentation: A tool of simulation of Urban Heat Island 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact The research outcome of the Tool of Simulation of Urban Heat Island has been presented in a British Council organised event 'UK high technology transfer to China' in 10-12 April in Chongqing. The description of the poster of the research outcome including Urban Heat Island simulation tool has been exhibited in the 10th China Chongqing High-tech Fair and the 6th China International Exhibition of Military & Civil Technologies (CCHTF & CIEMCT) on 12-15 April, 2012.

After the presentation, local media interviewed. Further collaboration in studying the UHI in Chongqing was proposed with Chongqing academic colleagues and funding bodies.
Year(s) Of Engagement Activity 2012
 
Description Simulation tool of urban microclimates 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Presentation to the consultants at the AEDAS, an Architecture and Urban Planning Company to explore potential application in practice.

Introduction of the microclimate simulation tool in Aedas in order to seek further funding such as KTP project.

After the presentation, a simulation project was assigned for a case study.
Year(s) Of Engagement Activity 2011
 
Description Urban microclimates and renewable energy use in cities 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact In this study, the accessibility to the solar energy and wind energy in the city environment is analyzed with respect to building layouts and their orientations. For passive solar housing in cities or urban applications of wind turbines and/or solar energy, the main challenge is the obstructions of the urban layout. This study provides an assessment of this problem.

The speech was presented at the Low Energy Architecture section with about 40 audiences.

After the presentation, international audience from China expressed interests in research collaboration
Year(s) Of Engagement Activity 2011