Paul C. Cropper

Coupling a model of human thermoregulation with computational fluid dynamics for predicting human–environment interaction

This article describes the methods developed to couple a commercial computational fluid dynamics (CFD) program with a multi-segmented model of human thermal comfort and physiology. A CFD model is able to predict detailed temperatures and velocities of airflow around a human body, whilst a thermal comfort model is able to predict the response of a human to the environment surrounding it. By coupling the two models and exchanging information about the heat transfer at the body surface, the coupled system can potentially predict the response of a human body to detailed local environmental conditions. This article presents a method of exchanging data, using shared files, to provide a means of dynamically exchanging simulation data with the IESD-Fiala model during the CFD solution process. Additional code is used to set boundary conditions for the CFD simulation at the body surface as determined by the IESD-Fiala model and to return information about local environmental conditions adjacent to the body surface as determined by the CFD simulation. The coupled system is used to model a human subject in a naturally ventilated environment. The resulting ventilation flow pattern agrees well with other numerical and experimental work.

Heat wave adaptations for UK dwellings and development of a retrofit toolkit

Purpose – Dwelling retrofit strategies generally concentrate on measures to reduce energy use and carbon emissions. However, climate change projections predict increases in both the frequency and severity of extreme weather events, including heat waves. It is predicted that by the 2040s severe heat waves similar to the European one in August 2003 may be expected to occur every year. Future guidance therefore needs to combine mitigation with adaptation in order to provide safe and comfortable dwellings, whilst also reducing heating energy use, within the available retrofit budget. The paper aims to discuss these issues. Design/methodology/approach – The research presented here used dynamic thermal simulation (EnergyPlus) to model a range of passive interventions on selected dwelling types to predict the effect on both dwelling overheating during a heat wave and annual space heating energy use. The interventions include modifications and additions to solar control, insulation and ventilation. Findings – Res...

Low energy refurbishment strategies for health buildings

Public health buildings contribute significantly to UK carbon emissions. New build initiatives have received more attention than the considerable opportunities to reduce carbon emissions within the retained health estate. The research reported here has considered the environmental performance of a typical medium rise, medium depth, concrete-framed, late 1960s acute hospital following low energy environmental design interventions. The interventions are made to optimize daylighting and natural ventilation/cooling whilst reducing overheating caused by summer time solar gains. Three options are investigated: advanced natural ventilation using plena and exhaust stacks; fan-assisted natural ventilation in which fans are used in the exhaust stacks; and mechanical ventilation/cooling with heat recovery. Computer simulations have been carried out to predict the influence on thermal performance (overheating risk) and energy consumption of each of these options on the original design. For each case, current weather data, and future weather data for the years 2020, 2050 and 2080, have been used.

Assessment of interventions to reduce dwelling overheating during heat waves considering annual energy use and cost.

Climate change projections indicate that the UK is expected to experience more frequent and more intense heat wave periods over the coming decades. Buildings frequently experience overheating even under the present climate, resulting in discomfort, health complaints and even mortality. Current house building rates are low, resulting in a need to adapt the existing building stock to provide more comfortable and safe environments. Dynamic thermal simulation computer modelling was used to assess and rank the effectiveness of selected single and combined interventions (adaptations) in reducing overheating during a heat wave period for a range of dwelling types, orientations and occupancy profiles. It is shown that solar protection interventions, such as window shutters and solar reflective coatings, can be amongst the most effective at reducing overheating during heat wave periods, but with a corresponding increase in annual space heating energy use. Whereas the addition of wall insulation, though beneficial for reducing energy use, may in some cases actually increase summer overheating. The results and guidance are presented in a way that allows identification of parts of the building stock most at risk and rapid selection of the best performing interventions in terms of overheating reduction, cost and annual energy use. It is also shown that above certain cost levels there is a diminishing return in both overheating performance and energy use reduction. The results of this research will provide important information to support refurbishment decisions of both individual house owners and landlords responsible for multiple properties, such as housing associations and local authorities.