English

Photocatalytic oxidation (PCO) is a new approach that destroys chemically the pollutants instead of adsorbing them into a matrix. A high conversion of organic pollutants can be obtained with no production of ozone. The PCO unit disinfects the air and experimental studies indicate that a wide range of bacteria can be eliminated.

This paper reports the test results of a new photocatalytic oxidation air filter unit (PCO unit) that has been designed for aircraft cabin applications. The performances of the PCO technique have been measured in a single pass mode test rig to show its ability to decrease the amount of VOCs entering it, and in a multipass mode test rig to measure its ability to clean the air of a room polluted with the same VOCs. The results are promising but the development of that photocatalytic air filter must go on.

This paper is a sum up of the new ventilation requirements in Flemish region published in the Belgian "Moniteur" on June 17th 2005. The legal framework for the new regulation is given by the Decree on the Energy Performance and Indoor Climate, adopted by the Flemish Parliament ; the technical specifications are given in Execution Orders, approved by the Flemish Government.
There are two different sets of requirements :

In this paper, results of air leakage testing in newly constructed multi-unit residential buildings are presented, they show that individual apartments are relatively airtight. Energy use can be reduced, odor transfer between apartments can be prevented and occupant safety is enhanced during fire emergencies.

The strongest justification for lowering ventilation rates would be epidemiological studies that link ventilation and health effects in several building types. In the past 25 years, few studies addressed that question in USA. But Swedish studies that revealed that health risks increased in residences when ventilation rates were reduced could serve as a model for the epidemiological study we need. In the meantime, we must be cautious and not reduce our minimum standards for ventilation rates until the efficacy of these reductions should be demonstrated.

Ashrae 62.1 and 62.2 standards set minimum ventilation rates that provide acceptable indoor air quality (IAQ) in occupied places. But these rates contribute to building mold problems in hot, humid climates. The aim of this paper is to see if those minimum ventilation rates should be lowered in those regions, or if other options could mitigate the problem, including energy recovery ventilators, stand-alone dehumidifiers, and low sensible-heat-ratio air-conditioning equipement being developed by the industry.

This paper describes the performance of a comprehensive experimental study to evaluate the capabilities of 6 different air-cleaning devices that included either HEPA filtering or electrostatic precipitation. Five were portable and were intended to provide air cleaning for bedroom-sized rooms. The sixth was situated in front of the headboard to affect the particulate population for sleeping persons. To ensure a completely objective study, a special laboratory facility was constructed.

Five ionic air purifiers - two wearable and three stationary - producing unipolar air ions are evaluated in this study.The aim is to check their ability to reduce aerosol exposure in confined indoor spaces.The data suggests that the unipolar ionic air purifiers are particularly efficient in the breathing zone when used inside confined spaces with a high surface-to-volume ratio, but a periodic cleaning of those indoor surfaces is needed.

According to the authors, there is a way to increase levels of filter efficiency while reducing the expense of the upgrade. The objective is to define the lowest cost system and not the lowest price system : to determine the best filter for the best cost. The 3 major components to life-cycle costing formula are initial investment and maintenance (that can easily be computed), energy consumption and disposal (that are more complicated to analyze). Examples are given.

In this article a conventional DX system is compared to three other all-electric enhanced dehumidification DX system packages to provide insight into their respective preformance capabilities. The author's conclusion is that augmenting a conventional DX cooling coil with enhanced dehumidification components (such as a wraparound heat pipe heat exchanger, a desiccant dehumidifier in a wraparound configuration too, or a post coil desiccant dehumidifier regenarated by condenser waste heat) can substantially increase an integrated system's moisture removal capacity.