PR1999

The performance of a hybrid air-conditioning system which utilises wind-induced cross ventilation is investigated. The characteristics of flow and temperature fields are examined using CFD simulation under various conditions of inflowing outdoor air i.e. air temperature, air exchange rate and width of the opening for cross ventilation. In this simulation, the room air controlling system (VAV system) which is used to keep the task zone at a target temperature is reproduced through changing the supply airflow rate of the air-conditioning system.

The paper presents the results of the tests of two-zone airflow pattern forming in a room with displacement ventilation where various heat sources and various airflow rates were tested. The position of the interface layer between the zones was determined experimentally - on the basis of tracer gas concentration measurement and on the way of calculation - on the basis of the plume model above a point heat source complemented with experiment. The following heat sources were used: a plume simulator, a desk lamp, a computer, a round plate and a human body.

Measurements of ventilation rates and indoor climate parameters were carried out in fiveEstonian residential buildings. The purpose of the study was to investigate potentialdifferences-between residences in former eastern Europe and Scandinavia, as regards theindoor environment. Air change rates were measured both during wintertime and springtime,and the air temperature and relative humidity were monitored both outdoors and indoors overextended periods of time. A variety of both organic and inorganic air pollutants weremeasured using both passive sampling and continuous monitoring.

A number of studies have shown that approximately 1 in 10 hospital in-patients will acquire a nosocomial infection (NI) '*).These infections are associated with significant mortality rates, and have a large economic impact on health care systems. A Department of Health (DoH) study estimated that in acute care hospitals in England 950000 lost bed days and financial costs off 111 million (1986 rates) were associated with NI '3).Through the use of ultraviolet germicidal irradiation (UVGI) lamps it ii possible to achieve a high degree of pathogen disinfection.

The aim of this study is to illustrate the importance of the effects of wind turbulence on airchange in buildings. Using two simple configurations, tested over a short period, twoapproaches are compared.The tests are performed using m experimental house which is filly exposed to the wind.

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.

This paper deals with the internal environment of traditional excavated dwellings in Santoriniand the effect the conditions of the surrounding volcanic rock have on it. Three buildings weremonitored in the summer and winter and the results of the monitoring were used to simulatethe natural ventilation of the dwellings and calculate the amount of moisture which is releasedfrom the porous material of the walls. The study shows that the internal high relative humidityvalues are mainly due to this moisture release.

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.

It is recommended to keep the ventilation filters dry. However there are manyventilating systems that cannot fulfil this requirement all the time. It is then interestingto know the state of filters in use, and how they perform during extreme wetconditions, especially at the end of their lifetime.This investigation includes used filters collected at the time of normal change offilters.The used filters absorbed a different amount of humidity. The particle filtrationefficiency was nearly the same as for unused filters (comparing only filter classF7/EU7).

This study is part of an investigation of the decontamination capabilities of indoor plants.Three internationally used species, Howea forsteriana Becc. (Kentia Palm), Dracaenaderemensis Eng. Janet Craig, and Spathiphyllum Petite (Peace Lily), were evaluated for theability to reduce or remove benzene and n-hexane from indoor air. Plants tested in bothpotting media and hydroponic conditions removed the individual VOCs at concentrationsequal to 2 and 5 times the maximum occupational exposure levels recommended by theWorksafe Australia Time-weighted average exposure standard (TWA), [1].