Ventilation strategy, energy use and CO2 emissions in dwellings-a theoretical approach

Summary An equation is developed for predicting the combined effect of naturally and mechanically induced air flows in buildings and solved by a combination of analytical and iterative methods. The resulting two-dimensional formulation, implemented as a simple computer program, allows rapid, hourly simulation of infiltration in domestic-scale buildings with a range of ventilation strategies. This implementation is used to compare energy use and carbon dioxide emissions for three ventilation strategies—natural ventilation, mechanical extract and balanced, whole-house mechanical ventilation— as a function of dwelling airtightness. This exercise confirms the need for airtightness if the benefits from balanced mechanical ventilation with heat recovery are to be maximised. List of symbols g Acceleration due to gravity (m s-1