Papers by Koen Steemers
Architectural Science Review, 2020
Green infrastructure enhancements are widely supported to address urban heat-related risks. The c... more Green infrastructure enhancements are widely supported to address urban heat-related risks. The challenge of implementing enhancements in dense cities has necessitated the development of surface greening, with vertical living walls having gained increased prominence in recent years. This paper considered the performance of such in-situ applications to quantify the extents of their influence on the microclimates of two sheltered urban conditions. The results highlight the potency of hygrothermal modifications to be most apparent within the proximate zone, with other phenomena introducing mixing to disrupt influence distribution. Air movement data at the indoor study also highlights a dominant daytime downward flow that encourages the formation of a microscale centripetal thermal system. This flow lacks potency to cause discomfort, although has capacity to present thermal sensation and diversity to occupants. The findings therefore highlight the necessity for installation designers to take account of proximity influence, and in future designs increase building occupant access to their canopies.
Architectural Science Review, 2020
In response to the need to mitigate urban heat risks, green infrastructure enhancements have been... more 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 decisionmakers and designers when considering the inclusion and sustainable maintenance of such greening installations.
CISBAT 2019 Special Issue of Journal of Physics: Conference Series, 2019
To address the call for developing passive climate resilience strategies, the project examines th... more 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.
Energy and Buildings, 2019
A warming climate, increasing frequency and severity of extreme heat events, and the heat island ... more 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. The method for addressing this utilises the novel approach of coupling a computationally efficient urban climate model with an established building energy model to simulate a residential street canyon within the London heat island. Key findings highlighted adaptive capabilities to achieve summertime ‘comfort’ in most rooms without the need for energy intensive mechanical cooling. The alternative of using indiscriminate and widespread mechanical cooling within the canyon length is estimated to result in a 0.4 K increase in nocturnal canyon temperatures, and an additional 4.4% of CO2 released to the climate. In contrast, a targeted approach of cooling rooms where adaptive capacity is insufficient more than halves the canyon CO2 emission estimate; which in turn highlights the necessity for detailed overheating assessments in managing energy use in such traditional residential neighbourhoods within UHIs.
Building and Environment, 2019
Environmental thermal loading on urban buildings is expected to increase owing to the combined in... more 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.
Building Research & Information, 1998
This paper explores the relationship between the geometry of urban neighbourhoods and the microcl... more This paper explores the relationship between the geometry of urban neighbourhoods and the microclimatic effects of solar radiation. It presents both the modelling techniques and key ndings with the aim of quantifying solar absorption and its relationship to the urban heat island effect. The impact on the urban environment and building energy consumption is discussed, which raises potential implications for design. This work discusses only one main environmental factor, solar radiation, which is part of a larger ongoing research agenda addressing wider aspects of the urban microclimatic.
PLEA 98 Passive and Low Energy …, 1998
This paper introduces a new EU-funded research project ("PRECis -assessing the Potential for Rene... more This paper introduces a new EU-funded research project ("PRECis -assessing the Potential for Renewable Energy in Cities") and summarises the findings of a recently completed project ("Project ZED -towards Zero Emission urban Development"). Project ZED demonstrated the potential of defining key urban form characteristics, using image processing software, and linking these to environmental performance of a section of a city, assessed using computer and physical simulation. Project PRECis goes on to refine and validate this work by relating the theoretical work to actual urban projects as well as microclimatic and energy use data. The result of the research is the development of a simplified urban bioclimatic design tool which responds to intermediate or neighbourhood scale issues.
Energy and Buildings, 2003
Investigating thermal comfort conditions in outdoor urban spaces, has thrown some light on the co... more Investigating thermal comfort conditions in outdoor urban spaces, has thrown some light on the complexity of the issues involved, demonstrating that a quantitative approach is insufficient in describing comfort conditions outdoors. It revealed that although microclimatic parameters strongly influence thermal sensation, they cannot fully account for the wide variation between objective and subjective comfort evaluation, whereas, psychological adaptation seems to becoming increasingly important. This paper concentrates on the issue of psychological adaptation: naturalness, expectations, experience (short-/long-term), time of exposure, perceived control and environmental stimulation, and presents an attempt to try and evaluate the relative impact of each of these parameters. Understanding the interrelationship between the different parameters of psychological adaptation would be of interest in order to compare their relative significance, and to assess their design role, that is whether design considerations would influence these parameters, or vice versa, whether they could influence design decisions. An awareness of these issues would be valuable to architects, planners and urban designers, not by the way of limiting possible solutions, rather by enriching the design possibilities. #
Lighting Research & Technology, 2002
... and R Compagnonc PhD aHellenic Open University, Greece bThe Martin Centre for Architectural a... more ... and R Compagnonc PhD aHellenic Open University, Greece bThe Martin Centre for Architectural and Urban ... In summary day-lighting quality has been presented in the litera-ture in two ways: ... on experience;13 or 2) by recommending a series of visual comfort criteria based on ...
Proc. REBUILD 1999: Shaping Our Cities for …, 1999
This paper investigates the nature of thermal comfort outdoors, the different kinds of adaptation... more This paper investigates the nature of thermal comfort outdoors, the different kinds of adaptation, and the way these differ from indoors. Mechanisms of adaptation in open spaces are examined at a physical and psychological level. Two kinds of physical adaptation are identified, reactive, corresponding to personal changes (clothing insulation, metabolic heat with consumption of cool/hot drinks, spatial variation) and interactive, corresponding to interaction with the environment to improve thermal comfort. The fact that physical adaptation cannot adequately justify the big discrepancy between objective and subjective comfort evaluation implies that psychological adaptation plays an important role in evaluation of thermal comfort conditions outdoors. This includes: naturalness, expectations, past experience (short-and long-term), time of exposure, perceived control and environmental stimulation. Evidence for these parameters is investigated. Parallels are drawn with the indoor environment where possible. Such a comparison could prove beneficial for thermal comfort theory indoors, as it would give a further impetus to a continuing debate, which has developed for over twenty years. Finally, it is suggested that by taking such parameters into consideration, the design of urban spaces can be enhanced, to improve thermal comfort and consequently increase the use of such spaces. Such an approach would be valuable to urban designers not by way of limiting possible solutions, rather by enriching the design considerations.
Proceedings by Koen Steemers
35th PLEA Conference, A Coruña, Spain, 2020
Green infrastructure enhancements are widely advocated to address heat-related risks in cities. T... more Green infrastructure enhancements are widely advocated to address heat-related risks in cities. The challenge of implementing enhancements in dense cities has necessitated the development of surface greening, with living walls having gained increased prominence in recent years. This conference paper considered such in-situ applications to quantify the extents of their influence on the microclimates of two sheltered urban conditions. The results highlighted the potency of hygrothermal modifications to be most apparent within the immediate zone, while the disparity between the two studies suggested that with increased shelter the influence is likely to be weaker. Surface temperature monitoring results from the indoor case study presented significant variation. While this was not potent enough to cause radiation asymmetry associated discomfort, thermal sensation and diversity to occupants is probable. These findings highlight the necessity for designers to take account of this proximity influence, and in future designs to increase building occupant access to installations.
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Papers by Koen Steemers
Proceedings by Koen Steemers