The Modelling of Overheating in UK Homes

Mo Khan is currently working as a Mechanical Design Engineer at calfordseaden while taking a one year sabbatical from his PhD studies at Loughborough University, UK. Read on to find out more about his research on modelling methods on overheating protection.

I worked with calfordseaden from 2013 to 2017, which is when I moved to Pakistan and then eventually to Qatar where I worked for four years as a research associate with Qatar Environment and Energy Research Institute (QEERI) on buildings energy modelling and HVAC related research. This mainly involved buildings simulation, load assessment, design and construction of a pilot solar cooling plant and a small building at the solar test facility of QEERI for experimentation. During these four years I also worked on the SUNEX project (Sustainable Urban Food-Water-Energy Nexus). The project aimed to establish an integrated modelling framework of advanced tools to model and assess the FWE systems’ demand and supply sides and capture their interdependencies through a nexus view that endorses sustainable and efficient solutions for energy, water, and food supply for urban regions and surrounding areas. I have published 5 peer reviewed research articles, co-authored a successful research grant proposal and contributed to two patents.

I remained in touch with the M&E team at calfordseaden while I was working abroad, and in 2021 I was accepted for a PhD position at Loughborough University with a great recommendation from Terry.

I moved back to the UK in October 2021 and rejoined calfordseaden in July 2022, where I have been involved in carrying out overheating assessments on several projects. This is proving to be extremely beneficial to my PhD research project entitled “Improving the Modelling of Overheating in UK homes.”

There are guidelines and Building Regulations to assess and target the overheating risk in buildings (e.g., Building Regulations Part O, CIBSE TM59:2017, CIBSE TM52:2013), though there is uncertainty in the reliability of predictions using the dynamic thermal modelling. However, dynamic thermal modelling is the only realistic overheating risk assessment approach to determine at the design stage of an unbuilt dwelling whether it will overheat.

My PhD research project aims to evaluate the impact of modelling methods on overheating prediction, and to develop the most suitable approach for modelling the commonly found features in UK homes (e.g., internal gains, solar heat gain, infiltration etc.) that influence indoor temperatures. Model validation techniques and sensitivity analysis will be used to determine the most influential parameters of the model for making reliable predictions about overheating. The comparison of model predicted and measured overheating (temperature monitoring in dwellings) for individual homes and large stocks of dwellings will help in determining whether correct overheating patterns are produced by models.

The results of this research work aims to inform designers and architects when complying with Building Regulations Part O (overheating), and provide support to CIBSE for more reliable guidelines to improve building performance.

At calfordseaden, we are endeavoring to engage with architects, engineers, acousticians and with the client, from an early stage, to provide a practical solution to reduce the risk of overheating in buildings, and to achieve a pragmatic approach to Building Regulation compliance.

I’m currently working on a number of schemes for overheating assessment including a development in central London, consisting of a block of 73 new-build, one to four bedroom dwellings. This development highlights the challenges of reducing overheating, whilst also accommodating reductions in noise and pollution levels within the home. Façade issue such as window opening restrictions, ventilation levels and solar shading question the fundamental form and function of the building envelope, giving opportunities for new ideas to tackle long term overheating in buildings.

These challenges are also acutely emphasised in another current development in central London which is providing 263 new build and mixed-use dwellings. This site is exposed to high levels of noise and pollution from road traffic and the surroundings, requiring an almost sealed façade, creating potential elevated temperatures within the building. The complexity of mathematically modelling the building and the façade to simulate the effects of noise, pollution and overheating mitigation is a key element of my work and research. Therefore, working with the design team and client to realise a pragmatic approach to these, often conflicting design aspirations, enables a unique understanding of the impact of building and environmental physics.

It is these exciting and multifaceted challenges that have brought me into engineering; and at this crucial time, in sustainable building design, it allows me to engage as part of the team to open new opportunities to passively achieve excellence in building performance.

Finally, my ongoing findings are helping me reach the conclusion that to ensure the practicality of overheating mitigation strategies, along with façade design performance, dynamic computer modelling methodology needs to be improved and project teams need more coordination and engagement at an early stage of a project.