Passive Cooling Design Strategies for Retrofit of Residential Tower Blocks in Northern Cyprus

This research investigates potential passive design strategies for improving the thermal performance of existing residential tower block (RTB) in Famagusta, Northern Cyprus. In a Mediterranean island that experiences hot and humid temperatures throughout the year, residential buildings need to be adaptable to the climate in order to improve the thermal comfort of occupants. The current housing stock includes a prevalence of high density, medium and low-rise residential tower block developments without implementing any insulation materials. The objective of this study is to develop and test passive cooling design strategies into retrofitting ill-performing residential tower blocks in the coastal city of Famagusta. As an initial step, the performance of a case study was modelled and simulated via employing Integrated Environmental Solutions - Virtual Environment (IES-VE) software add-ins Apache-Sim Dynamic Thermal Simulation. The results from the base case model were analyzed according to the adaptive comfort of CIBSE Technical Memorandum 52 guidelines: The Limits of Thermal Comfort – Avoiding Overheating in European Buildings. The spaces studied (living room and bedrooms) within the case study sample flats were observed to exceed the acceptable limits of thermal comfort; particularly living rooms with this zone exceeding the upper limit for overheating by up to 9 hours daily. The main reasons for the problematic thermal performance were identified as resulting from: infiltration through the building fabric, the lack of sufficient ventilation through the living spaces and excessive heat gains through the large areas of glazing. The internal operating temperatures of the simulated flats remain high throughout the day and night in a typical summer day, ranging from a maximum of 36.5°C to a minimum of 28.5°C. The study also analyses the effectiveness of two basic passive cooling strategies (shading and night ventilation) of 3 sample flats sharing the same orientation, and floor plan but located at different levels within the RTBs. Furthermore, the implications in the seasonal cooling and assessment when considering the adoption of climate-related set-point temperatures (i.e. adaptive comfort approach), beyond the assumed common standard, are also evaluated

Assessing overheating risk and thermal comfort in state-of-the-art prototype houses that combat exacerbated climate change in UK

There is growing evidence that terraced houses—thermally lightweight, well insulated, naturally ventilated with three exposed wall surfaces—are at risk of overheating, especially in south-eastern England. The aim of this study is to evaluate the building performance and develop a reliable building simulation, which will be employed in the second phase of the study: developing affordable and feasible passive design strategies to support the energy-efficient building systems of the construction industry. This paper reports on the results from the first phase of the study where a quantitative methodology, including indoor and outdoor environmental monitoring, in-situ measurements and building simulation modelling, was adopted. The performance of a case study was modelled and simulated via employing Integrated Environmental Solutions (IES) software suite. The results from the base-case were analysed according to the adaptive thermal comfort of Chartered Institution of Building Services Engineers (CIBSE) Technical Memorandum 52 guidelines: The Limits of Thermal Comfort—Avoiding Overheating in European Buildings. The spaces studied within the case study house were observed to exceed the acceptable limits of thermal comfort; particularly, the large bedroom within this zone exceeded the upper limit for overheating up to 11 hours daily. Furthermore, the results from the monitoring study indicate a high risk of summertime overheating across all the case study settings, especially during short-term peaks in outdoor temperatures. The main reasons for the problematic thermal performance were identified as well-insulated and fully air-tight building fabric, the lack of sufficient ventilation through the living spaces and excessive heat gains through the composite cladding material

Assessing Energy use and Overheating risk for Retrofitting A Residential Tower Block Prototype in Northern Cyprus

This study evaluates the energy performance of a residential tower block (RTB) development in Northern Cyprus in providing thermal comfort for its occupants. Severe summer temperature conditions in the coastal city of Famagusta includes significant daily oscillations in air temperature (14°C-45°C) and high levels of solar radiation, which contributes to the overheating of thermally inefficient building envelopes. Notably, 43% of the domestic buildings in Northern Cyprus are RTBs. As could be expected in residential buildings located in a hot and humid climate the cooling and heating comprise the largest part of the total energy consumption (73%). The aim of this is to investigate the applicability of passive design elements for the case study using three representative residential tower blocks (RTBs) each representing a different orientation (south-west, south-east and north-west). The research adopts a ‘quantitative’ research design; primarily building performance evaluation using modelling and simulation. The selected three RTBs are modelled using Integrated Environmental Solutions (IES) software where extensive dynamic thermal simulations have been produced to test passive design measures applied to improve thermal comfort and energy performance. This paper presents an analysis of the thermal performance of the three RTBs before different retrofit scenarios are applied to optimize the buildings energy performance and occupants’ thermal comfort. According to the results of the dynamic thermal simulation, cooling energy consumption saving of around 81% are achieved. The findings demonstrate the necessity to consider passive design strategies for effective retrofitting of existing RTB developments in Northern Cyprus

The significance of occupancy profiles in determining post retrofit indoor thermal comfort, overheating risk and building energy performance

Recently, retrofit of tower blocks has gained momentum particularly in the UK social housing sector due to the increasing rate of fuel poverty coupled with deteriorating indoor living conditions. However, the process of making improvements to the thermal performance of building envelopes can significantly impact on occupants’ thermal comfort, increasing overheating risks with the changing climate and associated heat waves. The first phase of the study evaluated the building energy performance of a 1960s social housing tower block prototype in London, pre-retrofit, where the building simulation model was created and calibrated with monitored indoor data and occupants’ interviews. The second research phase, the subject of this paper, uses the model to further investigate the impact of improved thermal insulation of the building envelope, based on U-values prescribed by the UK Building Regulations (Part L1B), on the potential risk of overheating. The study investigates the impact of retrofitting on occupants’ thermal comfort and building energy performance in the current and future climate scenarios (2030, 2050 and 2080). Results confirm that improving the U-value of external walls will significantly reduce the heating energy use by 70% under future climate scenarios while the Tₒ increases by 15-17% with U-value of 0.5 W/m²K and 0.3 W/m²K in comparison to the base case. The overall results indicate that the different occupancy patterns adopted in the simulation model have a significant impact on the predicted duration of overheating which will, in turn, have an impact on determining appropriate retrofit strategies to reduce overheating risks

To what extent can solar control be effective in enhancing indoor comfort in a fully glazed office building?

It is acknowledged that people spend almost 90 percent of their time in indoor spaces. Therefore, achieving a comfortable indoor environment that encourages productivity is crucial, particularly in office buildings. This paper investigates the design and performance of a modern office building in London characterized by fully glazed facades of open plan office spaces with no natural ventilation. The purpose of the research is to investigate the correlations between the control of direct solar radiation access and the effect on occupants' thermal comfort in the summer followed by assessing the potential effect of the application of passive solar shading on thermal comfort levels in the office spaces. The research methodology involves a survey questionnaire undertaken with employees of the office building, followed by dynamic thermal modelling of the building using Integrated Environmental Solutions (IES) software. The questionnaire has been designed to understand occupants' experiences within their office spaces and their strategies to improve the indoor environment. Furthermore, IES modelling and simulation provide in depth understanding of the building thermal performance and investigating the solar shading strategies. Overall, 66 questionnaire forms were completed where preliminary results demonstrated that most employees relied heavily on secondary cooling and heating systems to adjust the indoor air temperature for more satisfactory thermal comfort levels in their office spaces. The building modelling and simulation is used to quantify the direct solar radiation accessing the office space, the risks of overheating and the potential impact of solar control on occupants' indoor comfort. The findings from this study demonstrate the potentially high hours of discomfort in the summer within the office spaces mainly due to the lack of control of direct solar access through the extensive area of glazed facades. In order to maintain the thermal environment within the comfort level threshold in the warmer seasons a solar shading strategy should be considered

Hydrological Study of Groundwater and its Appropriateness for Irrigation

Irrigation in most countries represents the largest share of all water use. Groundwater is the main water resource after the water of the Nile River in Egypt. The water situation in the future is not optimistic due to the economic development, the increase in population growth and the increase in the agricultural area, especially after the completion of the construction of Ethiopian Renaissance Dam, so suitable alternatives must be provided for irrigation water. This paper presents a hydrological study on groundwater for use in irrigation in Assiut, Upper Egypt, so that alternatives can be provided to the Nile River for water used for irrigation purposes and appropriate uses. The experiments were performed using an experimental form created to achieve the purpose of the study. The model consisted of a cascade aerator and a sand filter. packed bed filter was added to be filled with some media before the sand filter. The media that were used in the study were plastic balls (80 mm), gravel (5-8 mm) and coarse gravel (15-30 mm). The results showed that use of water leads to improving the efficiency of groundwater and thus making it suitable for irrigation purposes. Using this model with the addition of the media used in this study, groundwater was improved by up to 90% and therefore it could be used for irrigation. Finally, it is believed that the results of this study are useful in hydrological studies of groundwater for conditions similar to the ones under which this study was conducted

Towards Energy-efficient Retrofit of Council Housing in London: Assessing the Impact of Occupancy and Energy-Use Patterns on Building Performance

This study investigates an energy-inefficient council housing tower block in London, due for retrofit, by exploring the correlations between occupancy and energy consumption patterns, thermal comfort and building energy performance in the winter. The aim of this study is to evaluate the building performance and develop a reliable building simulation model to be employed in the second phase of the study for developing an energy-efficient and cost-effective retrofit strategy to support the council's plans. The research seeks to demonstrate the significance of using dominant occupancy and energy use profiles as opposed to relying on standardised profiles when calculating building energy consumption using building simulation software. The paper reports on the results from the first phase of the study where a quantitative methodology; including a questionnaire, structured interviews, indoor monitoring, and building simulation modelling was adopted. The results provide evidence that occupants’ socio-demographic characteristics have a considerable impact on household energy consumption and fuel bills. The results also show that indoor environmental issues experienced in many flats are partly attributed to the thermally inefficient building envelope and partly due to occupants’ patterns of operating their homes with evidence of excessive heating energy use in attempts to alleviate the indoor issues experienced

An investigation into energy consumption behaviour and lifestyles in UK homes: Developing a smart application as a tool for reducing home energy use

The research asserts that several domestic retrofit programmes in the UK have not achieved the expected levels of energy saving. Energy consumption is not only reliant on physical characteristics of buildings, but also on the consideration of socio-cultural and economic factors. One of the issues is that the predicted home energy use does not reflect the actual energy consumed – a phenomena acknowledged as the ‘Building Performance Gap’. This research examines the factors that impact on domestic energy performance in response to this phenomenon. It adopts a concurrent mixed-method research design where the research method is primarily questionnaires to understand occupants’ energy consumption behaviour and lifestyle and develop a viable methodology to improve this. The solution could be the development of a smart application that addresses most energy consumption habits and behaviours connected to smart meters. As a result, occupants will be advised in real-time with appropriate energy-related behaviours if inefficient energy consumption is detected. Besides, the application will also comprise of a simplified Building Energy Simulation (BES) interface to provide building energy simulation results and evaluation. It is believed that this tool could potentially increase occupants’ awareness of energy consumption behaviour and reduce the Building Performance Gap

Improving the Building Performance and Thermal Comfort of an Office Building to Reduce Overheating Risk

In recent decades, efficient design of office buildings has become increasingly important due to its direct impact on occupants’ health, wellbeing, and productivity. Research found that issues within the indoor environment of the workplace, such as poor ventilation, lighting, and high levels of harmful gases and air borne particles has a significant influence on reduced productivity. This study aims to investigate the issues of overheating and propose strategies for retrofit of a modern office building in London as a case study. To achieve the research aim; a quantitative research methodology is adopted comprising three methods of data collection and analysis; a survey questionnaire, indoor data monitoring, and dynamic thermal modelling and simulation. The results show a significant improvement in the building thermal performance by retrofitting the building roof envelope where the indoor air temperature reduced from 29.3 to 26.9°C hence potential improvement of occupants’ thermal comfort.

Evaluating Thermal Comfort and Overheating Risks in A Social Housing Prototype: As-Built Versus Retrofit Scenarios

Climate change has highlighted the importance of thermal comfort and its health-related outcomes, particularly for the most vulnerable members of society living in social housing. Due to their vulnerable living conditions, low-income people are more exposed to negative outcomes of overheating and cold indoor temperatures in buildings. Previous studies suggest that there is a significant risk of overheating in retrofitted buildings both for the current and future weather scenarios. The UK government has introduced new building regulations to assess and limit the risk of overheating in new buildings; however, there is still a need to assess and improve conditions for existing and retrofitted properties. This study aims to evaluate the effect of retrofit strategies on thermal comfort and the risk of overheating in social housing under current and future climatic conditions. A typical case study building was simulated in DesignBuilder to assess thermal comfort conditions for upgraded building fabric to Part L of the UK building regulations and Passive House standards. The summer results were analyzed according to CIBSE TM59 while the Predicted Mean Vote index (PMV) was used for winter analysis. Findings revealed that the south-facing bedrooms are most exposed to overheating. Risk of overheating significantly increased for the future weather scenarios by up to 10 times while winter thermal comfort improved for the retrofitted scenarios