An examination of development models for innovative, low carbon, ecological dwellings for rural areas of Wales

 

The provision of housing in rural areas has been identified as crucial for the long term

sustainability of rural communities. However, there are questions about how rural

developers are responding to legislative requirements to reduce carbon emissions,

whether the fulfilment of a need for affordable housing in rural areas can be reconciled

with higher energy performance and whether higher energy performance will affect

thermal comfort when climate change is taken into account. To understand these issues a

review of published and monitored case studies in rural areas of the UK was undertaken

which highlighted a number of development models that might be applied by house

builders in the Welsh context. An analysis of two exemplar projects in Pembroke Dock,

West Wales, examined the following: the social, economic and legislative context of rural

development; the significance of energy and carbon used to construct rural houses; and

the quantity of energy required to keep rural dwellings at a comfortable temperature in a typical year. Dynamic thermal modelling was then used to investigate a number of design approaches

highlighted in the earlier studies as significant including: increasing thermal mass;

increasing south facing glazing; adjusting building form and the layout of the site; and

higher levels of insulation. The application of these approaches on a housing scheme in

West Wales established the benefits of incorporating thermal mass into the building

fabric, maintaining a compact form and, where reasonable, using passive solar gain, to

reduce heating load. This study identified that these approaches, if carefully combined,

could achieve significant (i.e. 16.4%-29.8%) reductions in heating load without

compromising the affordability of the original scheme. However, the study also identified

that one possible consequence of improving the energy performance would be a

reduction in thermal comfort as a result of higher internal temperatures. To gain a better

understanding of this further modelling examined the potential for overheating using the

following: current and future climate files; an algorithm based on window opening

behaviour; detailed simulation of airflow; and bivariate data analysis techniques. The

results from this study identified that thermal mass and ventilation techniques could be

employed to address the issues of overheating.