Natural and decentralised ventilation and climate concepts: A proposal for a new hybrid concept

This report tries to answer the question: Can a hybrid system, combining the good air quality and low costs of a natural system with the useradjustability, energy efficiency and small size of a decentralised mechanical system, offers a feasable, sustainable alternative to current ventilation concepts? In an attempt to do so, the Climat Cavity facade concept has been developed, a facade that uses the glass cavity to either pre-heat supply air with thermal energy leaving the building through the facade and solar radiation, or uses the cavity to extract solar heat gain and room air by using the solar chimney effect. The climate cavity facade concept aims to invest the same money that would otherwise be spend on a (central) ventilation system, into the facade which provides the ventilation, but simultaneously offers the advantages of a second skin facade, being reduced energy consumption in terms of heating and cooling and improving thermal comfort. Apart from that, the concept offers a low maintenance and low fan-energy ventilation system, that always provides fresh air without the interruption of filters, heat exchangers or ducts. Also, the concept allows users to influence their climate and make decisions in terms of pre-heating and conditioning air, opening a window and solar heat/light entry. Where the second-skin facade and climate facade concepts rely on mechanical ventilation for the interior, the climate cavity facade aims to be a natural alternative, providing air directly from the outside and using buoyancy and solar radiation to help provide ventilation. The Climate cavity, a ‘natural ventilation - decentralised mechanical ventilation’ hybrid system, can offer improvement in terms of maintenance, fan energy, solar heat gain, user/room adjustability, space consumption and air quality. On the other hand, points of critique are the relatively low heat recovery at this moment, investment costs that could be higher, the uncertainty of cleaning frequency and acoustic comfort. These points will require further research and development before the concept can be applied to an acutal building.