ventilation

The future is well-isolated buildings with low heating demand. The first office building in Norway satisfying the passive house standard, the GK environmental house in Oslo, was taken into use in August 2012.

The impact of over-tempered air on the perceived indoor climate was evaluated by questionnaires filled in by the users of the first office building with passive house standard in Norway. In this building, the heating demand is covered entirely by warm air supplied into the rooms through the ventilation system.

For the coming energy-efficient buildings, the guarantee of energy performance becomes a major challenge. It is therefore crucial to implement accurate and reliable measurements, in order to ensure this performance. The in-force French EP-regulation RT2012 already imposes compulsory justification of envelope airtightness. Moreover, the Effinergie+ label requires ventilation systems control and ductwork airleakage performance. These requirements, ventilation controls for IAQ concern and regulatory compulsory controls of buildings need reliable diagnostic protocols.

The ventilation required in order to maintain acceptable indoor hygiene standards results in a significant consumption of energy. Currently the Spanish regulations on indoor air quality (IAQ) require minimum rates for delivery-to and extraction-from the habitable rooms of residential buildings. These rates are not adjustable, so ventilation systems based on variable ventilation rates, are not normally deemed acceptable unless a comprehensive statement of compliance is provided, justifying the proposed ventilation solution.

Carbon dioxide included in exhaled breath is often used as a tracer gas when estimation of ventilation aspect in buildings with occupants is performed. Carbon dioxide produced by occupants is the key for the estimation. JIS A 1406 and ASTM D6245-12 refer personal carbon dioxide production rate. However JIS does not take into account personal attribute like as body height and weight. On the other hand, ASTM does not take into account gender difference and based on average westerner adult data.

Envelope airtightness is incorporated in the French Energy Performance (EP) Regulation (named “RT”) and is a key factor in the reduction of energy consumption. From 2006 until 2012, the French 2005 Energy Performance Regulation (RT, 2005) did not require justification of envelope airtightness. However, constructors could get certification for airtightness through a quality management (QM) approach, in order to build better-than-regulatory buildings.

New homes currently being built within the UK all incorporate some type of ventilation system, the majority of which are of the fixed mechanical fan type. These generally come in three generic designs known as single room background ventilators, continuous mechanical systems and continuous mechanical systems with heat recovery. Installation, inspection and commissioning of these systems is covered by Building Regulations, and there are training schemes in place which allow individuals to become Competent Persons to undertake these tasks.

Facades must meet with continuously increasing requirements concerning design quality and technical performance. It will be shown that neither extremely simplifying nor highly detailed simulation tools with complete geometrical representation really help to develop new facade types during the early stages of design. Due to simplified physical modelling, conceptual variations may not be adequately represented and this means that different properties cannot be seen.

In a previous study, a whole room IAQ model consisting of multi-phase emission/sorption model for wall materials and room volume mass balance model catering for practical ventilation schemes was developed. The interactions between volatile organic compounds (VOCs) and building materials composing different building components can thus be modeled based on fundamental mass transfer theories. In the present study, the effects of various ventilation strategies and outdoor source on the indoor gas phase VOC concentration are investigated by simulating different building scenarios.

A full-scale test room is used to investigate experimentally and numerically the velocity and temperature fields in the case of a mechanical ventilation. Detailed fields are measured for three cases of ventilation air temperature: an isothermal case, a hot case and a cold case. The experimental data are used to test two turbulence models: a first order k-ε turbulence model and a second order RSM turbulence model. The RSM model predicts the temperature and velocity fields better than the k-ε turbulence model.