The effects of air change and ground covers on crawl space moisture balance in a cold climate are discussed in this paper. The objectives were to assess the suitability of outdoor air-ventilation in the crawl spaces of apartment buildings, to determine the optimum air change rate with and without ground covers, and the effect of the ground covers' thermal insulation on moisture behaviour. Measured data from the test building was used to develop the crawl space model in a modular simulation environment, where the parametric simulations were carried out.
Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2-9.5 months following installation and in seven new site-built houses 1-2 months after completion. The houses were in four projects located in hot-humid and mixed-humid climates. They were finished and operational, but unoccupied. Ventilation rates ranged from 0.14-0.78 h-1. Several of the sitebuilt houses had ventilation rates below the ASHRAE recommended value.
Forty sites were visited during a survey of exposures to diesel engine exhaust emissions. Personal and background exposure to gaseous components, respirable dust, elemental carbon, organic carbon and total carbon were measured and details of control systems were recorded. The results show a wide spread in exposure patterns reflecting the different work practices, job categories of employees and the control methods used. However, sites where fork-lift trucks were in use consistently produced the highest exposures.
Indoor air quality (IAQ) challenges outnumber all others in the health care industry. Unfortunately, the cost conscious powers that be have failed to make the management of critical infection control systems a top priority.
Calculation of design cooling loads is of critical concern to designers of HVAC systems. The work reported here has been carried out under a joint ASHRAE-CIBSE research project to compare design cooling calculation methods. Peak cooling loads predicted by the ASHRAE heat balance method are compared with these predicted by a number of implementations of the admittance method using different window models. The results presented show the general trends in overprediction or underpredictiori of peak load. Particular attention is given to different window modelling practices.
Architecture and engineering journals have been increasingly attentive to innovative non-residential buildings designed with operable windows. Such buildings may rely exclusively on natural ventilation for cooling, or may operate as mixed-mode, or "hybrid" buildings that integrate both natural and mechanical cooling. Architects who want to incorporate natural ventilation as an energy-efficient feature need to collaborate closely with mechanical engineers.
The airborne transmission of disease is a constant threat and while diseases such as Tuberculosis were considered all but extinct in the western world, the resurgence of it demonstrates that the spread of these diseases has to be taken very seriously. This paper describes the method of application of Computational Fluid Dynamics (CFD), more appropriately called Airflow Modelling for the Building Services Industry, to the airflow and heat transfer in a Hospital Isolation Room Application.
To investigate the dispersion of aerosols in an airflow, a test facility was build at the HermannRietschel- Institute. The distribution of aerosols across the cross section of the test duct was measured at several distances from the emission source. The turbulence intensity of the airflow in the duct was varied by installing different turbulence generating grids (I% to 20%) at the top of the test duct. Far enough downstream the source, the concentration profiles have a Gaussian distribution.
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