The Buildings, Energy and Environment Research Group warmly invites you
to attend their Wednesday Seminar on 24th November at 12.00pm, B5 Marmont
Guest speakers: Cagri Kutlu - Research Fellow
Tianhong Zheng - PhD Student
“A versatile PCM energy storage system for building applications”
Abstract:
Latent heat storage units have been developed for years because their high energy density allows storing large amounts of energy in relatively small volumes. However, for long-term storage, heat losses of conventional PCM systems are still a considerable problem where heat is lost continuously to the ambient environment and is thus wasted, when the system is not in use. Supercooled PCMs will be a solution to this as the latent heat is only released when triggered. This feature allows storing the heat at ambient temperature without loss. This project investigates the integration of supercooled PCMs into building space heating applications. A solar-assisted heat pump with a latent heat storage unit model has been built to provide heating to a house in Nottingham.
Biography:
Dr Cagri Kutlu is a postdoctoral research fellow at the Building, Energy and Environment research group at the University of Nottingham. He holds PhD in Sustainable Energy Technologies from the University of Nottingham in 2020. His research interests are refrigeration and air conditioning, solar thermal power systems, heat storage and demand-based system modelling.
“Investigation of the sustainable technologies for mitigating urban heat island in the subtropical climate area”
Abstract:
As a consequence of the industrial revolution, the urban heat island (UHI) effects were first observed in London in the 19th century. This phenomenon is described by the eremitical development of higher temperatures in urban areas compared with the surrounding rural areas that directly surrounds them. It is a global phenomenon covered by a warmer climate condition that can increase energy consumption, air pollution, and carbon dioxide emission. Recently, the intensity of UHI is increased due to the change of original urban microclimates. Besides, the extensive reduction of vegetation and evapotranspiration and the advanced manufactured building fabric and material have high solar absorption, low albedo (solar reflectivity), high impermeability, which also can contribute to the UHI.
Moreover, the increased urbanisation improves the higher anthropogenic heat. The 2018 Revision of World Urbanization Prospects presented that the world's urban population has overgrown from 751 million in 1950 to 4.2 billion in 2018. Asia significantly has 54 % of the world urban population. The drastically increased population contributes to new megacities, and the existing megacities become more populated. Therefore, the UHI is getting more and more serious.
Furthermore, the negative impacts of UHI can affect human life quality. The UHI jeopardise the health of citizens negatively in many ways, such as heat syncope, cardiovascular stress, thermal exhaustion, heart stroke and cardiorespiratory diseases. Thousands of deaths are annually happened due to heat-related illnesses. UHI has become one of the most critical environmental problems for high-density cities.
However, there are some effective UHI mitigation strategies improved in recent years, which can be used to oppose the impact of UHI. The UHI mitigation techniques aim to balance the thermal budget in urban areas by increasing thermal losses and decreasing the corresponding gains. Some criteria of UHI mitigation must be prioritised depending on the diverse condition of urban regions, such as environmental temperatures, energy-saving and outdoor air quality. For dissipating the excess heat, increasing the albedo of the urban environment and expanding the green spaces in cities both are great ways, such as improved urban morphology design, green infrastructure development, expansion of highly reflective pavements, and application of phase-changing materials (PCM). The research questions are which mitigation strategies are the most effective way to mitigate UHI in a specific city centre? is there any new strategy which is more suitable for this city centre? What is affecting the different mitigation strategies of the UHI problem in terms of building energy on a city scale?
The study aims would analyse the microclimate with UHI through the spatial distribution analysis, urban meteorological parameters, urban morphology parameters, properties of materials, and anthropogenic heat emissions with some three-dimensional model simulations. The study results and answers can provide valuable guidance to local government and departments on which UHI mitigation strategies are most effective and suitable for the local city centre, which can attract the local policymakers, urban designers and planners, construction material developers, researchers. The policy implications based on this research can keep building cooler and guide how the subtropical climate cities can become more sustainable in the future.
Biography
Tianhong Zheng is a PhD student at the Building, Energy and Environment research group at the University of Nottingham. She is in her PhD final year and will hold PhD in Sustainable Energy Technologies from the University of Nottingham in 2022. Her research interests are urban heat island, urban physics and optimisation, human thermal comfort, microclimate change and building energy simulation.