Passive energy recovery from natural ventilation air streams

Abstract

Increasing levels of urbanisation and indoor air quality have led to enhanced research and development of sustainable technologies in buildings. This study investigated natural ventilation streams typically found in domestic buildings and used heat pipe technology to recover the energy from them. Computational Fluid Dynamics (CFD) based numerical code was used to predict the rate of heat transfer from a heat pipe heat exchanger model. The present numerical code was successfully validated against experimental data from literature. Pure water as a natural phase change material was employed to investigate the overall effectiveness of the heat pipe heat exchanger. Six models with varying vertical heights between the pipes were developed in order to investigate the optimum column pitch. A good correlation between the computational and analytical results was observed. The work focused on the vertical column height between the heat pipes and its impact on the overall rate of heat transfer, depicting an inverse relationship between the two parameters. The findings demonstrated the prospect for pre-cooling by 15.6°C and that a recovery of 3.3°C using this system which would assist in reducing energy consumption loads from the heating, ventilation and cooling sector, offering significant reduction in the carbon footprint of domestic buildings.