Evaluating the feasibility of 'zero carbon' compact dwellings in urban areas

Reducing the carbon footprint of domestic properties is, due to global warming and social impact of increased energy costs, an ever increasing priority. Although the compulsive building standards are set by the building regulation part L1, The Code for Sustainable Homes have set more stringent requirements above the requirements of Building Regulations to achieve zero carbon emissions during occupation. This Code for Sustainable Homes (CSH) requires all new homes to be zero carbon by 2016. Land scarcity and lower number of people per household forces developers to develop compact apartment-based dwellings on brown field sites, constraining the design. The aim of this research is to understand the effect of practical constraints on real building design and technology on achieving zero carbon performance in compact urban dwellings in a maritime northern European climate. In this work, currently commercially implementable renewable generation technologies are evaluated for their suitability in a compact urban setting. A model-based approach is developed to evaluate the energy consumption (both regulated and unregulated) and energy balance under the specific constraints of compact urban buildings. Graphical representation enables the introduction of a demand envelope, which shows the boundaries of the minimum and maximum expected thermal and electrical energy consumption over one year period. The research has three key findings: 1.Due to variations in energy consumption by the occupants, mainly by the unregulated energy consumption, multiple renewable energy technologies would have to be implemented to achieve the lowest possible carbon emission. 2.Although the combination of PV, CHP and HP is the generation option with the lowest carbon emissions, it is not completely carbon free when producing the required electrical and thermal energy. This suggests that there is a high likelihood that zero-carbon energy generation can not be achieved in this case study of a compact urban dwelling with the currently available technology. 3.The simulations show that with highly insulated dwellings the amount of space heating required is less than 10% of the overall energy consumption, as opposed to the 60% generally achieved in the building industry. Subsequent on-site measurements showed an estimation of just under 30% of the total energy consumption was used in space heating, which is higher than the simulated value, but still less than half that of a conventional dwelling. The main academic recommendation resulting from this research is a requirement for further ongoing research into new generation technologies as they become mature. Recommendations for the sponsoring company include continuation of measurements at the case study building to enable confirmation of energy consumption/generation findings so far