exhaust

No longer relegated to the garage or the workshop, the search for more power is taking over the kitchen, as commercial-sized kitchen fans invade the home. The problem is, residential kitchens aren't regulated the way commercial kitchens are. This causes potential hazards when these huge fans are turned on.

The most critical aspect of the operation of any air-distribution system is the way that conditioned air is delivered to the occupied space, says Paul Jones         

The IEA project Annex 27, Evaluation and Demonstration of Domestic Ventilation Systems,have come to the stage that simplified tools can be presented in a total scheme. At earlierAIVC conferences some of the tools have been presented in separate papers and still the toolsare under development. In this paper a more general approach of the usage of the tools is to bepresented.The work is based on the joint work of participants from both AIVC countries (CAN,F, NL, S, UK, USA) and non-AIVC countries (I, J).

Many dwellings with natural or gravity ventilation systems suffer from poor airchange rates. In Sweden, especially houses built in the 1960-ies and 1970-ies heated with electric resistance heating and thus without chimneys, are at risk. Improving the airchange rate in these houses is to some extent performed to decrease Radon gas concentrations where appropriate. For comfort, most homeowners learn to live with low airchange rates, accepting e.g. odours or window condensation and trying to compensate this with increased airing.

The use of local exhaust is considered to be the most effective way to control pollutant dispersion from intense sources, such as in kitchens, in toilets, as well as in copy machine rooms. The optimum air exhaust rate required to prevent pollutants from escaping into the major occupant areas very much depends on the natural air exchange rate(AER) between the hooded room and the major room space. This paper presents a mathematical model and a test procedure of using tracer gas technique to quantify the AER.