Abstract:
Modern buildings and their HVAC systems are required to be not only energy-efficient but also produce
fewer economical and environmental impacts while adhering to an ever-increasing demand for better
environment. Research shows that building regulations which depend mainly on building envelope
requirements do not guarantee the best environmental and economical solutions. In the current study,
a modified multi-objective optimization approach based on Genetic Algorithm is proposed and
combined with IDA ICE (building performance simulation program). The combination is used to minimize
the carbon dioxide equivalent (CO2-eq) emissions and the investment cost for a two-storey house
and its HVAC system. Heating/cooling energy source, heat recovery type, and six building envelope
parameters are considered as design variables. The modified optimization approach performed efficiently
with the three studied cases, which address different summer overheating levels, and a set of
optimal combinations (Pareto front) was achieved for each case. It is concluded that: (1) compared with
initial design, 32% less CO2-eq emissions and 26% lower investment cost solution could be achieved, (2)
the type of heating energy source has a marked influence on the optimal solutions, (3) the influence of
the external wall, roof, and floor insulation thickness as well as the window U-value on the energy
consumption and thermal comfort level can be reduced into an overall building U-value, (4) to avoid
much of summer overheating, dwellings which have insufficient natural ventilation measures could
require less insulation than the standard (inconsistent with energy saving requirements) and/or additional
cost for shading option.
