The impacts of climate change on the electricity demand of archetypal office buildings

UoM administered thesis: Phd

Abstract

Mitigation and adaptation to climate change impacts will be one of the most important challenges to societies over the twenty-first century. Global average temperatures are likely to increase above the 2°C threshold, probably around 3°C. Therefore, it is vital to prepare and develop approaches to adapt to the impacts of climate change and design for climate resilience. The effect of warming climates in buildings drives additional cooling requirements in them, leading HVAC (Heating, Ventilation and Air-Conditioner) systems to their capacity limits and then to indoor thermal discomfort. In addition, heatwaves can lead to a sharp increase in the daily peak electrical demand, hindering and stressing the power grid operation, while the ongoing energy transition is already driving multiple challenges to its operation. This thesis set out to explore the potential effects of future climate change impacts on the cooling demand of office buildings, and quantified the implications for power network operation, in different regions of the world. It examines the impacts of climate change upon cooling requirement and total and peak electricity demand for three type of office buildings (small, medium and large office reference models) in six different cities (Singapore, Cairo, Athens, Beijing, Lisbon and London). Firstly, an assessment was conducted of the sensitivity of cooling and electricity demand of existing office building model to changes in building design assumptions. Secondly, the effects of potential weather variability on the total electricity demand of office buildings was analysed. Finally, a climate pathway framework was developed to capture the uncertainty in the future weather data, and used to quantify the impacts of climate change for the cooling demand of office buildings and evaluate the reduction effect of potential adaptation strategies. The effectiveness of six adaptation measures was analysed: increasing cooling set-point temperature to 27oC, reducing lighting and equipment densities, increasing the HVAC system coefficient of performance, reducing the ventilation rate and the solar heat gain coefficient of windows. The research findings showed that lighting and equipment density, cooling setpointset-point temperature, coefficient of performance and ventilation rate, make a significant contribution to the total electricity demand in office buildings. In general, the response of peak electricity demand (total and for HVAC end-use) is larger than for annual demand for all office buildings across most of the locations analysed. In addition, the findings show that a uniform 5°C increase (shift) in dry-bulb temperature variable values lead to rise up to 26.8% and 38%, respectively for peak and annual total electricity. The effects on the electricity demand of offices under the climate pathway lead to an increase from baseline in total annual electricity demand, can reach up to 38%, and for peak total demand can go up to 62%, associated with maximum dry-bulb temperature increase of 12.7°C. For HVAC demand, the level of change from the baseline was found that could be much larger (182% for annual and 158% for peak). However, using the combination of six adaptation measures, the total electricity demand can be maintained below current baseline demand levels, both for annual (results are below baseline at least by 8%- large, 16% - medium or 27% - small offices) and peak demand (13% - large, 11% medium or 29% - small). In all model simulation runs, the HVAC systems were automatically sized to respective correspondent weather data scenarios. The research findings provide a better understanding of the overall energy demand implications of the modelling uncertainty for offices, both by design assumptions and weather variability. These findings also intend to propel building energy modellers and building designers to further interrogate the implication of these uncertainties across different climates and different types of buildings with different building characteristics. The research framework introduces a systematic and openly available procedure to assess the effects of climate change in buildings, incorporating uncertainty in the generation of future weather data. In addition, the framework enables the systematic assessment of the effectiveness of multiple adaptation measures under a span of future weather conditions.

Details

Original languageEnglish
Awarding Institution
Supervisors/Advisors
Award date1 Aug 2022