Refresh: Remodelling Building Design Sustainability from a Human Centred Approach

Lead Research Organisation: University of Leeds
Department Name: Civil Engineering

Abstract

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Publications

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Gilkeson N.A. (2018) Computational fluid dynamics simulations of personalised ventilation: Sampling air quality in the breathing zone in 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018

 
Description The Refresh project (Universities of Reading, Leeds and Southampton) explored the impact of urban microclimate on building ventilation for optimal performance of occupants. We have used a range of methods (measurements, wind-tunnel modelling, CFD, qualitative interviews, controlled EEG tests) across idealised and realistic buildings to understand better how we respond to poor air quality, and how natural ventilation can help to improve it.

Building-microclimate interactions

University of Reading researchers completed the Refresh Cube Campaign (RCC) at Silsoe, UK, in collaboration with the University of Birmingham. It was the first field study of natural ventilation for an idealised array of cubical "buildings" under realistic weather conditions. Engineering standards often include design data for isolated cubical buildings, which motivated the experiment. The 9 month-long experiment used haybales stacked as cubes to represent buildings surrounding an instrumented test building where ventilation was measured. Pressure coefficients on the buildings were also modelled at the EnFlo wind tunnel laboratory at the University of Surrey. The University of Leeds developed and validated different CFD models against the RCC data for both internal and external flow, and investigated flow around the buildings and its effect on ventilation. Findings were:

On ventilation, models and engineering standards
* Cross ventilation rate for the array case was reduced by 50-90% compared to the isolated building when the wind was within ± 50° of being perpendicular to the window.
* Single-sided ventilation models, commonly used for design, underestimate the RCC field data by a factor of 10-20. Levels of turbulence are much higher for the RCC experiments than previous work - results suggest that turbulence can enhance ventilation rate when window size is relatively small (1% of wall area). This is a typical situation for buildings in dense urban areas.
* CFD simulation using OpenFoam (LES) and Fluent (RANS) compared reasonably well with RCC data and CIBSE standards in terms of pressure coefficients. Ventilation rates agreed within the spread of the RCC data, with cross ventilation easier to predict than single-sided.
* When comparing traditional methods of ventilation measurements, tracer gas results underestimate compared to pressure-based results. This is more the case for single-sided ventilation than cross ventilation and is dependent on wind direction.
* Pressure coefficients from wind-tunnel, CFD data and engineering standards data tended to underestimate the full-scale RCC test cube data. For the array case, RCC results did not agree with the standard data for individual building facets as the building layout is asymmetrical. However, the data for the pressure drop across the building agreed better.

On microclimate and flow
* Flow patterns around a building surrounded by buildings (the "array case") can switch between different states for the same background wind direction. This is due to complex interactions between building wakes and can lead to errors in predicted ventilation rates.
* Unsteady CFD simulations showed that an internal jet appeared for most wind angles for cross ventilation for the isolated building. For the array case, the internal jet was very weak; however, internal mixing seemed to be improved by the influence of unsteady flow outside the window.
* CFD simulation using a lattice-Boltzmann method (LBM) running on a GPU showed good agreement with Fluent simulations and RCC data. As LBM simulations are almost 10,000 times quicker, this shows promise for real-time flow simulation in the future which will aid building design.
Human-building interactions

Work was led by the University of Southampton on how people respond to poor indoor air quality (IAQ), and how technology could help them. A study was done to understand the social determinants of Indoor Environmental Quality in offices by conducting semi-structured interviews with occupants.

* Office environments were identified by occupants as being poor sometimes (ie too hot/cold, stuffy). Adjustments to windows, thermostats, radiators were made through negotiation with others, especially those who "owned" windows by sitting next to them. Other "gate-keepers" included building managers who adjusted the environment heating or ventilation.

A controlled experiment, testing the effect of "fresh" (low CO2 concentrations) and "stale" air (high CO2 concentrations) on cognitive performance, was done at the University of Southampton. EEG was used to monitor brain state and was as an objective measure of sleepiness. Other physiological, psychological and Sick Building Syndrome factors were also monitored.

* Cognitive performance was affected even after short exposures (<40 minutes) to high CO2, more so in people who were already sleepy. As there was no other measurable effect on participants, this suggests that poor indoor air quality can impact cognitive performance of office-workers prior to them being aware of it. IAQ feedback displays could assist people in changing their work environment for the better.

Understanding and optimising the measurement of indoor environments, and linking these with models and human data was carried out by all three partners. A device recording and displaying CO2 and relative humidity levels ("The Aether") was designed at the University of Southampton and trialled in offices. Based on the finding that IEQ is partly socially negotiated, the device needed to be visible to all - a "situated technology", like a clock on the wall. Through the EEG experiments the University of Reading evaluated the performance of IAQ sensors in an office environment and used this data together with external weather data to analyse the local flow and ventilation characteristics inside and around the test office. A wireless sensor network to map CO2 in real-time at multiple locations in a room was developed at the University of Leeds, and is now being used in a follow on project.

* A simple IAQ feedback device achieved straightforward sense-making, where participants understood the relationship between its readings, air quality, and the need to ventilate the room. Positive design features were its focus on only one indoor pollutant (CO2) and its minimal cues (simple traffic light display colours).
Exploitation Route Ventilation results are of potential interest to engineering consultants, architects and building service engineers who design ventilation systems for buildings or building layout/design in city redevelopment plans. Results will also be of interest to emergency responders in the case of contaminant ingress in buildings. Human-Building Interaction results are of interest to Human Computer Interaction practitioners and occupants and building managers making the most of existing buildings.
Another aspect of the project has been to contribute to a new area of Human Computer Interaction, becoming known as "Inbodied Interaction" where fundamental research about how the state of the body affects cognitive performance is contributing not only foundations for interaction but to our understandings of human performance. This work has informed the development of several international workshops in leading computer science venues like ACH SIGCHI (2019, 2019) and UIST 2019
Sectors Construction

Energy

Environment

URL http://www.refresh-project.org.uk/
 
Description Impact is still emerging however a number of activities have happened to facilitate impact from the project. Outcomes from the Refresh Cube Campaign at Silsoe on natural ventilation and associated wind tunnel and CFD modelling have been shared with a range of academics, practitioners and policy makers including: · Croucher Advanced Study Institute on Urban Climate (Chinese University of Hong Kong, Dec 2015, Barlow). Urban ventilation has been of great concern in HK since the 2003 SARS outbreak, when it was discovered that it had an airborne pathway, and therefore design and layout of buildings should promote access for all to fresh air. Collaboration with CUHK is ongoing, and a pathway to impact is via the Air Ventilation Assessment policy in place in HK, one of only two cities world-wide to directly take into account urban ventilation in the planning process. · In the UK contact has been made with Public Health England, BRE, the Chartered Institute for Building Services Engineers, the UK Wind Engineering Society, and a number of consultancy and architectural companies (including Arup, Fosters and Partners) who are all interested in the project. Through this engagement we have identified that the research findings may be relevant in future natural ventilation guidance (e.g. CIBSE), and we are actively exploring this. The project was a key driver in the establishment of the Low Energy Ventilation Network, a UK Fluids Network SIG, which brings together researchers and practitioners with an interest in the fluid dynamics aspects of ventilation. The network co-lead is Noakes and Barlow is on the management committee. We are also engaged with the UK Fluids Network Urban Flows SIG, and have been instrumental in setting up a new database for sharing urban flow data sets, which will include outputs from the Silsoe field campaign (Barlow). In 2020 this led to the award of substantial new funding to establish the Breathing City, Future Urban Ventilation Network under the SPF Clean Air programme. Work on both the natural ventilation analysis and sensors have enabled collaboration with the EPSRC Grand Challenge MAGIC project (lead Prof Paul Linden, Cambridge). This includes researcher forum meetings to share expertise on modelling and measurement techniques, participation in wind tunnel experiments and full scale urban flow measurements of the MAGIC test site in London, and collaboration on measurement of CO2 distributions in ventilated rooms and comparison of sensors. A wireless sensor network developed through Refresh is being using in this later collaboration, and is now being developed for application in hospital environments through the HECOIRA project (EP/P023312/1)
First Year Of Impact 2018
Sector Construction,Energy,Environment
Impact Types Societal

Policy & public services

 
Description Alfred P. Sloan Travel Grant
Amount $500 (USD)
Organisation Alfred P. Sloan Foundation 
Sector Charity/Non Profit
Country United States
Start 06/2015 
End 08/2015
 
Description Breathing City: Future Urban Ventilation Network
Amount £507,944 (GBP)
Funding ID NE/V002082/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 08/2020 
End 08/2024
 
Title Comparison of Silsoe Refresh Cube Campaign (RCC) Full-scale, Wind tunnel and CFD methodologies 
Description The information provided below is an overview of some of the key components. More information is included within the files stored into the database. Other data sets are also linked to. Full-scale: Measurements undertaken at Silsoe, UK, on a pressure tapped cube. Wind, temperature, surface pressure, and concentration measurements were undertaken. Most equipment measured at 10Hz aside from concentration measurements and meteorological measurements. The cube was isolated and surrounded by eight other cubes of similar size during the experiment to monitor the effects of sheltering. Wind-tunnel: Experiments were conducted in the Environmental Flow Research Centre (EnFlo), University of Surrey 'A' wind tunnel (low speed open circuit). The test section is 0.6 m high, 0.9 m wide and 4.5 m long and is constructed of wood and metal with glass side panels. Computer fluid Dynamics (CFD) simulation: A transient Navier-Stokes finite-volume simulation k-? sheer stress transport (SST) scale adaptive simulation (SAS) turbulence model was used to model the isolated cube and array at full-scale in Ansys Fluent 17.1 (Ansys Canonsburg, PA, USA). The k-? SST SAS model is a hybrid RANS-LES model that has shown superior results to steady state RANS and has been detailed for this purpose in King et al. (2017). For more details see: Gough et al (2019), Gough et al (2018a), Gough et al (2018b) and Gough 2017 (reference list included in files). 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
 
Description CIBSE nat vent meeting, Sheffield Sept 2014 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Interest in project

New contacts
Year(s) Of Engagement Activity
 
Description Contributed talk - Healthy Buildings Eindhoven 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A talk was given to the audience at the Healthy Buildings Europe conference in Eindhoven regarding the use of computational fluid dynamics for modelling the ingress of pollutants from street canyons. Some audience members (total approx 75) requested further information and a few sought future collaboration with the University of Leeds.
Year(s) Of Engagement Activity 2015
 
Description Indoor Air 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Third sector organisations
Results and Impact Contributed conference talk to Indoor Air audience members on the use of real-time CFD modelling techniques in urban airflow prediction. Audience requested further information.
Year(s) Of Engagement Activity 2016
 
Description Indoor Air 2018 Philadelphia Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Third sector organisations
Results and Impact Ran a computational modelling workshop at the Indoor Air Conference in Philadelphia, USA to an audience of about 30. These received it well and suggested that they had formed new opinions on the usefulness of novel modelling techniques.
Year(s) Of Engagement Activity 2018
 
Description Refresh- Remodelling Building Design Sustainability from a Human Centres Approach", ARCC Assembly, Birmgingham June 10-11th 2014 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Interest in project

New contacts
Year(s) Of Engagement Activity
 
Description WES 2014 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Wind Engineering Society presentation about CFD models in wind predictions. Audience members requested further information.
Year(s) Of Engagement Activity 2014
 
Description WES 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Third sector organisations
Results and Impact Wind Engineering Society prevention about real-time CFD in the use of airflow modelling. Audience requested further information.
Year(s) Of Engagement Activity 2016