More than three-fifths of the households in the U.S. heat or cool their homes with ducted forced air systems, so chances are good that air ducts are lurking within your walls, floors, or ceilings. These air ducts move conditioned air to warm and cool your family. They can be a great source of comfort-but more likely they are wasting energy and costing you money. Typical duct systems lose 25 to 40 percent of the heating or cooling energy put out by the central furnace, heat pump, or air conditioner.
Good indoor air quality (IAQ) enhances occupant health, comfort and workplace productivity. This issue has become more critical in a country like Singapore that has no other natural resources except manpower. In addition, Singapore is located in the tropical region with a hot and humid climate and a large number of the buildings are served by air-conditioning and mechanical ventilation (ACMV) systems to maintain a thermally comfortable indoor environment. The provision of a thermally comfortable indoor environment for the occupants is only one aspect in achieving better indoor air quality.
Much publicity has been given to the potential health risks posed by buildings, particularly those with mechanical ventilation or air conditioning. There have been concerns over the possible effects of the vocs given off by the furnishings and finishes, of fungal spores shed from dirty ducting, of legionella distributed by wet cooling towers, of insufficient ventilation air, etc., etc. The list of concerns is a long one. But what about the effects on the building occupants of the air brought in from outside, the so-called 'fresh air'?
We analyzed 1994 sick leave for 3,720 hourly employees of a large Massachusetts manufacturer, in 40 buildings with 115 independently ventilated work areas. Corporate records identified building characteristics and IEQ complaints.
The air, particularly the indoor air, contains a considerable burden of unwanted pollution. Overall there may be thousands of pollutants. They are brought in with the outside air or are generated from or within buildings. Most will be present in minute amounts but several will be present in measurable quantities. The reaction of people to the components of this pollution has little to do with toxicological assessment but is more concerned with political responses and media scares.
Efficient control of ventilation systems needs information on indoor air pollutant concentration. But most of the time, the pollutant concentration is not measured. However, outdoor air pollution forecast models are becoming operational and a relation between outdoor and indoor pollutant concentration may be used to predict pollutant concentration peaks and to infer recommendations to reduce its value . A prediction model of the outdoor/indoor air pollutant transfer, based on experimental data, was obtained using multiple linear regression.
The main purpose of buildings is to provide a comfortable living environment for their occupants. This includes, among others, thermal,visual and acoustic comfort as well as indoor air quality. Except during the 1950's and 1960's, it has always been considered important that an excess use of energy should be avoided in the construction and the management of a building, sometimes even at the cost of user comfort. Energy saving is, however, not the main purpose of the building.
Ultraviolet light has been demonstrated to effectively de-activate pathogens and all other airborne bacteria, virus and mould species. The technology is already widely used within process users of air, GMP manufacturers and by those with an interest in a high quality indoor air supplies, such as call centres, banks and other high employee density locations. The technology is now being applied to reduce the incidence of nosocomial infection at healthcare providers worldwide.
The aim of this Chapter is to break down barriers to concepts of natural ventilation. The study is part of a Pan European project titled NatVent that involves seven countries in the north of Europe. The project leaders are the UK Building Research establishment. Urban pollution is a major barrier to the adoption of natural ventilation, so successful ways of avoiding these problems need to be found.
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