Thermal performance of a naturally ventilated building using a combined algorithm of probabilistic occupant behaviour and deterministic heat and mass balance models

This study explores the role of occupant behaviour in relation to natural ventilation and its effects on summer thermal performance of naturally ventillated buildings. We develop a behavioural algorithm (the Yun algorithm) representing probablistic occupant behaviour and implement this within a dynamic energy simulation tool. A core of this algorithm is the use of Markov chain and Monte Carlo methods in order to integrate probablistic window use models into dynamic energy simulation procedures. The comparison between predicted and monitored window use patterns shows good agreement. Performance of the Yn algorithm is demonstrated for active, medium and passive window users and a range of office constructions. Results indicate, for example, that in some cases, the temperature of an office occupied by the active window user in summer is up to 2.6ºC lower than that for the passive window user. A comparison is made with results from an alernative bahavioural algorithm developed by Humphreys [H.B. Rijal, P. Tuohy, M.A. Humphreys, J.F. Nicol, A. Samual, J. Clarke, Using results from field surveys to predict the effect of open windows on thermal comfort and energy use in buildings, Energy and Buildings 39(7)(2007) 823-836.]. In general, the two algorithms lead to similar predictions, but the results suggest that the Yun algorithm better reflects the observed time of day effects on window use (i.e. the increased probability of action on arrival)

Living walls in indoor environments

© 2018 The warming climate, projected increase in frequency and severity of extreme heat events, and the long-established heat island phenomenon are all expected to exacerbate urban environmental thermal loading. Active means used for addressing such risks are likely to increase energy consumption and emission trends to create a positive feedback loop that could threaten the health and wellbeing of urban citizens. In response, passive approaches such as green infrastructure enhancements are widely advocated, and to meet the challenges of implementing enhancements in dense cities, attention has been directed toward encouraging surface greening. This paper recognises this trend and considers vertical greening as a developing interest with application opportunity in both exterior and interior urban environments. A review of available studies and interviews with experts found most observations available to be derived from exterior applications. Interior applications consequently have yet to be investigated to determine relative value to indoor environments where most of human habitation is typically concentrated. The integration of plant science studies in this regard is highlighted as essential to develop a balanced evidence base for the enthusiasm observed for promoting indoor living wall installations.EPSR

Urban living walls: reporting on maintenance challenges from a review of European installations

In response to the need to mitigate urban heat risks, green infrastructure enhancements have been widely advocated in recent times. To meet the challenges of implementing enhancements in dense cities, surface greening approaches such as vertical living walls have gained increased prominence. This paper reports on the principal challenges and drivers influencing the sustainable maintenance of such installations, identified through the inspection of ten European case studies and interviews with their management authorities. The study reports on key maintenance areas highlighted by installation managers as requiring attention. Furthermore, it reports on human engagement behavioural aspects as being a significant motivator, with installation managers assigning value to building occupant and public perception of an installation’s flourishing state. The evidence reported, therefore, is beneficial to key decision-makers and designers when considering the inclusion and sustainable maintenance of such greening installations.EPSRC Studentshi

Adaptive comfort assessments in urban neighbourhoods: Simulations of a residential case study from London

A warming climate, increasing frequency and severity of extreme heat events, and the heat island effect are cumulatively expected to exacerbate climate thermal loading on urban buildings. This in turn could lead to increased summertime overheating risk, with any active means for addressing this likely to influence future energy consumption and CO2 emission patterns. This paper examines how the microclimatic loading presented by the heat island (UHI) effect influences summertime adaptive comfort in traditional urban residential buildings.Funding: this work was partly supported by the Cambridge Commonwealth, European and International Trust, University of Cambridge

Energy retrofit and occupant behaviour in protected housing: A case study of the Brunswick Centre in London

This study examines the impact of behavioural and physical variables on the energy saving from retrofitting protected housing. Protected housing in England is referred to as ‘listed’ housing managed by English Heritage. The result of the study demonstrates that balanced approaches can be developed to retrofit listed housing by taking into account occupant behaviour factors, to meet the requirement of both energy efficiency and heritage conservation. A case study of the Brunswick Centre in London shows that the highest household energy use can be 2.2 times higher than average consumption. According to the modelling results from Integrated Environmental Solutions (IES) software, the impact of positive behavioural change ranges up to 62% to 86% of the total potential savings in the tested dwellings, where the lower behaviour change effect is associated with a higher retrofit level. However, rebound behaviour could offset estimated energy saving from physical improvement. Based on the findings, a framework of intervention measures is developed, which demonstrates that the proportion for behavioural change and building technology varies with respect to household energy use level. In summary, this study shows that in listed housing behavioural change has the potential to bring substantial energy saving far exceeding that from physical improvements, and thus tackling behavioural change plays a pivotal role in developing integrative strategies for listed housing retrofit.This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0378778814004113

Tailoring domestic retrofit by incorporating occupant behaviour

© 2017 The Authors. Published by Elsevier Ltd. Energy savings from building retrofits often fall short due to occupant behaviour. Current retrofit guidance may be significantly undermined due to standardised behavioural assumptions used in modelling calculations. This paper investigated the impact of household behaviour on the effectiveness and optimum ranking of domestic retrofit measures. It compared the energy saving potential from eight single retrofit measures across five household behavioural patterns, using a case study dwelling and dynamic building simulation modelling. The results confirmed that behavioural impact is significant in optimising retrofit strategies, suggesting tailoring domestic retrofit by incorporating occupant behaviour is vital for realising the energy saving potential

Effects of microclimate and human parameters on outdoor thermal sensation in the high-density tropical context of Dhaka

open access articleA thermal comfort questionnaire survey was carried out in the high-density, tropical city Dhaka. Comfort responses from over 1300 subjects were collected at six different sites, alongside meteorological parameters. The effect of personal and psychological parameters was examined in order to develop predictive models. Personal parameters included gender, age, activity, professiontype (indoor or outdoor-based), exposure to air-conditioned space and sweat-levels. Psychological parameters, such as ‘the reason for visiting the place’ and ‘next destination is air-conditioned’, had statistically significant effects on thermal sensation. Other parameters, such as ‘body type’, ‘body exposure to sun’, ‘time living in Dhaka’, ‘travelling in last_30 min’, and ‘hot food’ did not have any significant impact. Respondents’ humidity, wind speed and solar radiation sensation had profound impacts and people were found willing to adjust to the thermal situations with adaptive behaviour. Based on actual sensation votes from the survey, empirical models are developed to predict outdoor thermal sensation in the case study areas. Ordinal linear regression techniques are applied for predicting thermal sensation by considering meteorological and personal conditions of the field survey. The inclusion of personal and weather opinion factors produced an improvement in models based on meteorological factors. The models were compared with the actual thermal sensation using the cross-tabulation technique. The predictivity of the three models (meteorological, thermos-physiological and combined parameter) as expressed by the gamma coefficient were 0.575, 0.636 and 0.727, respectively. In all three models, better predictability was observed in the ‘Slightly Warm’ (71% in meteorological model) and ‘Hot’ (64.9% in combined parameter model) categories—the most important ones in a hot-humid climate

Living wall influence on microclimates: An indoor case study

Abstract To address the call for developing passive climate resilience strategies, the project examines the influence and effectiveness of utilising vertical greening for reducing space-conditioning loads of urban buildings and surrounding microclimates. By examining this focus, the project aims to improve the design of urban built environments that would in turn lead to health and wellbeing enhancements of their growing populations. The purpose of this paper is to present preliminary findings from a monitoring campaign carried out at an indoor atrium case study in Cambridge, UK. Key parameters monitored included soil, surface, and air temperature; relative humidity; and surface air movement. Results obtained show relatively lower air temperature and higher relative humidity levels proximate to the living wall. Wintertime monitoring has also indicated a surface flow pattern that demonstrates the presence of a modest downdraught effect. Although these modifications are modest in magnitude, they could still offer significant localised thermal comfort benefit to building occupants, as well as potential for contributing to a reduced space-conditioning load.</jats:p

Simulation pathway for estimating heat island influence on urban/suburban building space-conditioning loads and response to facade material changes

© 2019 Elsevier Ltd Environmental thermal loading on urban buildings is expected to increase owing to the combined influence of a warming climate, increasing frequency and severity of extreme heat events, and the urban heat island (UHI) effect. This paper presents how a computationally efficient estimation pathway could be utilised to understand UHI influence on building energy simulations. As an example, this is examined by considering UHI influence on the space-conditioning loads of office buildings within urban and suburban conditions, and how the trend of replacing heavyweight facades with lightweight alternatives could affect their surrounding microclimates, as well as building energy use. The paper addresses this through simulations of street canyons based on the urban Moorgate and suburban Wimbledon areas of London. Results show that with all scenarios including the UHI within a dynamic thermal simulation presents between 2.5 and 9.6% net increase in annual space-conditioning. The study also demonstrates that the trend in urban centres to replace heavyweight facades with lightweight insulated alternatives increases space-conditioning loads, which in turn increases UHI intensity to create a warming feedback loop. The study therefore stresses the significance of including microclimate loading from the UHI in estimating urban and suburban energy use, and the combined simulation approach is presented as a computationally efficient pathway for use by built environment designers

Extending the applicability of the adaptive comfort model to the control of air-conditioning systems

Extensive studies have been done on adaptive thermal comfort for naturally ventilated buildings. However, further studies of the adaptive comfort model are needed to develop a control method for buildings with the air-conditioning systems. This study aims to extend the application of the adaptive comfort model by developing an adaptive comfort control (ACC) for air-conditioning systems. Special attention is given to testing the acceptability of the ACC to the occupants of the office buildings. Two extensive longitudinal field studies were carried out that involved 807 office workers and a total of 13,523 individual comfort votes were collected. This study reveals that it is possible to develop statistically and substantively significant adaptive comfort models for the cooling operation of air-conditioned buildings. This field study provides scientific evidence that the adaptive comfort model can be used to control an air-conditioning system without sacrificing occupants’ thermal comfort. Further field studies on air-conditioned buildings are warranted to quantify the energy use implications of the ACC.Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning (Grant ID: 2014R1A1A2054494)This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.buildenv.2016.05.02