The design of natural ventilation systems - the configuration and sizing of system components - assumes one of two generic forms: the nasty form based on thermal comfort criteria or the nice form based on specified airflow rates. The nasty form demands consideration of the complex coupled interaction of a building's airflow and thermal systems - a difficult and often intractable challenge. The nice form, on the other hand, is quite tractable, yet it is commonly approached using interactive and approximate techniques.

A currently unresolved problem in building design in the paradox between increasing demand for good thermal insulation, and the requirement for ample levels of ventilation, to maintain a healthy indoor environment. A possible solution to this problem is a supply air 'ventilated' window. An experimental set-up has been designed to test the performance of the window under various conditions. The behaviour of the window is shown, and the factors affecting it's performance discussed.

Many HVAC systems built in the time between 1960 and 1980 have now reached the end oftheir lifetime and require retrofitting. When HVAC retrofits are performed in connection withbuilding renovation, there is often a potential for reduction of thermal loads. The questionwhether a renovated building should have an airconditioning plant or free ventilation oftenrevolves around arguments of energy consumption and investment. However it is not takeninto account that there can be no thermal comfort in many cases of cooling loads and outdoortemperatures.

Classrooms in New Zealand schools are mostly low rise buildings with natural ventilationdesigns, sized for summer cooling. This study has investigated winter ventilationperformance in twenty-four classrooms in twelve primary schools in the Wellington region.Its purpose has been to provide baseline data on the effectiveness of existing naturalventilation, along with approximate pollutant profiles on which to base new mixed modeventilation designs.

The need to separate impurities from air or other gases has increased as regards both the degree of separation and the necessity to separate finer particles. An 85% efficiency filter is a prerequisite for the correct functioning of ventilation systems and to improve indoor air quality (IAQ).

A test room was used to evaluate the impact of airflow parameters on the effectiveness of an air cleaning system. The room’s dimensions were nominally 11.2 m x 5.7 m x 2.7 m. The room has a drop-ceiling with space above for installation of above-ceiling air cleaning equipment and routing of ventilation ductwork. The HV AC system supplying the room could be turned on for constant flow (-349 ls·1) or left off to independently evaluate the effectiveness of the air filtration system.

A test rig for long-term tests of activated carbon filters was developed consisting of eight parallel test-filter sections. The test-rig was installed on the roof of a six storey commercial building located in the centre of Goteborg, Sweden. By this arrangement, eight activated carbon filters are tested simultaneously under realistic conditions, using the pollutants in the ambient outdoor air as challenge substances.

Ventilation filters composed of electrostatically-charged fibers, also referred to as electret filters,are know to have the potential to decrease in filtration efficiency with use. However, little datahave been available on whether such decreases are seen in actual applications.

Forced air furnaces are a common Canadian heating system. Traditionally, filters placed in thecirculating air ductwork were designed to protect the furnace and fans. Over the last severalyears, there has been increased emphasis on improving the filtration efficiency with the goal ofreducing occupant exposure to respirable particulate. The current research project rotatedseveral filters through six houses in southern Ontario during the heating season.

The cabin air filter performance is of prime importance for the air quality in vehicles. New clean filters were tested but also filters loaded with actual traffic contaminants. Both laboratory and field measurements were included in the study. Direct reading instruments and filter sampling was used for the loading rate determinations. The filter performance includes particle filtration efficiency with regards to particle size, filter loading and flow rate as well as filter pressure drop related to filter loading. Test results for these paramenters are presented.