English

This paper presents an analysis of air-to-air total heat exchangers (heat and mass transfer) built up using moisture permeable paper (but impermeable to air molecules). Performance of 6 such total heat exchangers made of different types of paper were tested, in order to know their air leakage ratio and their energy saving ratio. An analysis is presented about the effect of leakage on energy recovery efficiency.

A building energy similation code (ACCURACY) was used to compare indoor humidity in an office room in a hot and humid climate (Hong Kong weather condiitons) equipped either with a conventional constant volume all air system or with a chilled ceiling and a dessicant cooling system. The chilled ceiling and dessicant cooling provide better indoor humidity environment most of the time. The paper gives indications on how to avoid condensation on ceiling panels.

To increase our understanding of the olfactory and trigeminal (i.e., sensory irritation) impact of chemical mixtures we have studied the binary mixture butyl acetate/toluene. First, we measured complete concentration-response (i.e., psychometric) functions for the odor, nasal pungency, and eye irritation detectability of the single chemicals. Second, we selected fixed detectability levels between chance (p=0.0) and perfect (p=1.0) detection (e.g., p=0.6).

The study is a review of 600 articles to determine if indoor environments does influence student performance at school. The study has been extended to other categories (laboratories, offices). No direct relationship has been statistically shown but results suggest a link between ventilation rate and performance, as well as for presence of carpets, pollens or low efficiency filtration.

The aim of a study is to determine if on site, in a call-centre of 4600 m2, a correlation can be found between ventilation rate and performance of worker. No clear effect of ventilation rate on worker performance has been found in this case on the air flowrate variation range (12 to 48 l/s). Yet some improvements of performance are shown at very high ventilation rate.

Three offices ventilated with charcoal filtered outdoor air were investigated with different air change rates, ozone level and limonene, using the perception of a sensory panel. Results confirm that ventilation is necessary for ensuring good indoor quality even in low-polluting offices.

A simple method was used to assess odor intensity in indoor environments by a trained panel. Reliable results were obtained. Other factors, i.e., interaction with other senses, annoyance and other cognitive processes seemed to influence individual evaluation, especially during adaptation. Therefore, laboratory experiments could be useful to assess immediate odor intensity with minimum context influences. Comparison of odor sampled in Tedlar bags and in the living room were acceptable in terms of intensity but not in terms of recognition and description, indicating presence of biases.

This study investigated if low air temperature, which is known to improve the perception of air quality, also can reduce the intensity of some SBS symptoms. In a low-polluting office, human subjects were exposed to air at two temperatures 23 C and 18 C both with and without a pollution source present at the low temperature. To maintain overall thermal neutrality, the low air temperature was partly compensated for by individually controlled radiant heating, and partly by allowing subjects to modify clothing insulation.

The relationship between outside air ventilation rate and indoor VOC concentrations was studied through measurements in an office building (the call center of a health maintenance organization - 4600 m2 - 290 persons). Direct relationships between ventilation rate and concentrations were not found for most VOC's.

A survey was conducted in a new office building in Beijing (China) with mechanical air supply and natural exhaust, in which sick building symptoms were reported. Measurements and data from a questionnaire suggested that ventilation was insufficient.