Presents a mathematical model for the measurement of thermal comfort. Compares the results with previous measurements of air velocity in buildings with and without air conditioning.
Describes qualitative experimental investigation of the air flow in a scale model representing a typical, average hall. Smoke was used to display the air flows. A mathematical model was also developed. Determination of the turbulent air flow in the model confirms the suitability of the mathematical model foruse in quantitative experiments, in particular for measuring the heat flux density.
This paper presents the results of a computational and experimental study to assess the possible benefits of using mathematical modeling techniques for cleanroom design. A two-dimensional modeling visualization has been used for each of the cases studied. This has the advantage that its relative cheapness allows more design variations to be analyzed than would be possible with a three-dimensional method. Full-scale measurements were also taken in the cleanroom which was the subject of the modeling exercise.
The determining parameters for the formation of condensation are 1) the surface temperature of the building section and 2) the dew point temperature of the air in the room. Thermal bridges in intensively insulated outside walls and decreased ventilation due to tighter windows both increase the risk of condensation. Mechanical ventilation reduces the risk, but natural ventilation is dependent on occupant behaviour.
Reduced ventilation and infiltration, and new materials and machines have increased levels of indoor contaminants. Investigations of many indoor environments reveal contaminant levels above those set as standards for the workplace environments. The acute and chronic health effects on the population are not well known. This paper discusses the current general status of the research in the USA and the planned future effort. Worldwide research is also summarized and future directions are suggested.
Specific indoor air quality issues that have arisen in the UK in recent years have involved asbestos, formaldehyde, pesticide residues, radon and combustion products. Different measures have been taken with regard to each of these substances. In general, an education approach has been adopted, although national standards, industry self-regulation and some regulatory measures have been used. In the UK, control of ill defined, distributed or non stationary indoor air pollutants such as body odour, tobacco smoke and water vapour, is considered to be best achieved by suitable ventilation.
Most houses in the Netherlands are equipped with gas-fired heaters and cooking appliances, since large amounts of natural gas are available. Carbon monoxide poisonings occasionally occur due to the use of instantaneous water heaters (geisers) that are gas fired. An investigation was carried out to establish the carbon monoxide production potential of geisers under normal conditions of use. The study involved 254 houses: the results indicated that 17% of the geisers produced a carbon monoxide level of more than 50 microL/L in thekitchens where they were located, after 15 min of operation.
The influence of the various sources of pollution on the home environment in the Netherlands is reviewed, eg, outdoor air, gas-fired appliances, tobacco smoking and building materials. The pollutants carbon monoxide, nitrogen dioxide, particles and radon are discussed in more detail. Available data show that outdoor standards for air quality are often exceeded indoors. However, conclusions on exposure and health effects cannot be drawn until more data are available from random or stratified samples of houses.
Outlines some of the principles behind air driven aspects of moisture in buildings and illustrates how calculation methods and mathematical modelling techniques may be used to both predict and remedy associated problems. Primary remedies include a reduction in the generation of moisture, ensuring thermal integrity of the building and providing adequate ventilation. The use of dehumidification may also have a role to play. Mathematical models offer an inexpensive method for assessing design ideas at an early stage of development.
This paper reviews the work carried out in the Netherlands on moisture problems. In current air flow simulation models for buildings, moisture transfer and diffusion in and between rooms are not taken into account. The aim of the research project is the development of an integral hygrothermal model in which the above mentioned aspects are incorporated.
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