Natural ventilation, designing for Wellington non-domestic buildings

Abstract

The recent rise in interest in environmental issues and in particular the concern over the increasing use of non-renewable energy resources, has prompted investigation into energy efficient design and construction within the building industry. The use of natural ventilation fits well with this aim. The use of natural ventilation reduces energy requirements for heating and cooling (thereby reducing the emission of greenhouse gases), and also the use of ozone depleting substances that have traditionally been used in cooling systems. Furthermore requirements for artificial lighting may decrease as naturally ventilated buildings are often based around narrow plans allowing greater utilization of daylight. The use of natural ventilation in buildings can also result in compelling benefits for both the building owner and the building user. Recent studies Building Services Journal 'Probe Reports' have shown that savings can be made in construction, energy and maintenance costs. These costs must be evaluated in light of initial costs and ongoing costs, for example that a reduction in HVAC costs may be offset by increased building envelope costs or a reduction in plant area and duct space may be offset by the inclusion of an atrium. Furthermore, natural ventilation strategies allow occupants a degree of control over their environment. Studies have shown Bordass B. p 30 this can result in increased user satisfaction and productivity but only when acceptable comfort conditions are maintained. Natural ventilation strategies are not a new concept. In Wellington there are many large buildings that are naturally ventilated. New technologies (including computer modelling techniques) have enabled architects to adopt fresh perspectives and to gain a better understanding of how natural ventilation principles can be applied to modern construction and building form. The realisation that a closely controlled environment is not required in many instances and that people generally appreciate a 'natural' environment has led to a more considered approach to ventilation. Where required, natural ventilation strategies can be supplemented with mechanically assisted strategies or a mixed mode approach can be adopted.