In June 2001 ASHRAE's Standard Project Committee on "Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings", SPC 62.2P, recommended and the Board of Directors approved ASHRAE's second complete standard on residential ventilation for public review; this was followed by public reviews of independent substantive changes in 2002 . The standard is an attempt by the Society to address concerns over indoor air quality in dwellings and to set minimum requirements that would allow for indoor air quality and energy efficiency measures to be evaluated.
The aim of this document is to outline and summarize the principles to be followed when the aim isto produce and to install a clean air handling system. A large Finnish research and developmentproject CLEAN VENTILATION has focused on to find the main reasons and phases where theodours and other harmful pollution from the ventilation system originate. In the project bettertechnical solutions have been developed to produce cleaner components with less harmfulemissions.
The quantitative determination of differential pressure and airflow for proper room pressurization is an HVAC design area that has not yet developed a standard rule.In this article current design guidelines and field practices for room pressurization are investigated. Practical field tests were performed in two types of facilities: a tuberculosis research lab and a cell transplant unit.
The excitation of pulsed plasmas for the air treatment (odors, toxic and volatile gases suppression, and sterilization) needs fast high electric pulse generators with powers that can require high repetition frequencies according to the applications .This paper shows that those solid state generators are today available. They use several technologies thanks to a global approach of the high power electronics physics and recent evolutions of active and passive components.
The heterogeneous photocatalysis relies on the activation of a half-conductor. The most often used is TiO2, with radiations of energy at least equal to the ones of the width of the forbidden band.The electronic changes due to that activation lead, in the presence of air, to the creation of oxygenated radicals. Those radicals attack the adsorbed organic compounds and degrade them. Starting from evaluations made with a laboratory photoreactor, this paper shows that photocatalysis is an appropriate method to purify air in domestic buildings (or other confined spaces).
A simplified model for room cross-ventilation airflow has been developed using scaling analysis,experimental correlations and computational fluid dynamics. The model considers the main jet region and the recirculations region and leads to a set of formulas that predict the airflow rates and characteristic velocities in these two regions. Examples of application of the model to cross-ventilation design are presented.
This paper investigates, using CFD simulation, the influence on energy and comfort of the position of small openings for air exchange between rooms in ventilated and air-conditioned rooms of highly airtight houses. Measurements of velocities and temperatures were operated in a Japanese house with floor heating and central air conditioning system providing some fresh airl. Results agree with these of CFD calculations. Calculations were used to search for the optimal position of small ventilation openings between rooms.
This article describes bacteria and viruses usually considered as candidates for biological weapons. It also presents chemical agents that might be used as chemical weapons. It shows how HVAC systems can be designed with safeguards to protect against entry and/or circulation of these agents. It explains how air filtration can provide an additional defense, using HEPA filters, activated carbon filters, antimicrobial treated filters, ultraviolet light emitters or electrostatic air cleaners with UV emitters.
This article describes the various types of fungi (yeasts, molds, mushrooms, ...). It reminds that they are single or multi-cellular non-motile organisms which rely on other organism or environment for nutrients. Fungi can generate spores which can germinate under appropriate conditions (moisture, substrate, temperature) after an extended period during which they remain dormant.
The article presents the advantages of decoupling the outdoor ventilation air cooling and dehumidification from the space cooling and dehumidification. These dual-path systems (one air handling unit for outdoor air with total energy recovery, another air handling unit for the recirculation air, and a single air supply delivery system) are used in all-air variable air volume system designs. They can be combined with CO2-based demand controlled ventilation, which offers superior control and cost savings.
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