The Moravian library's atrium in Brno (Czech Republic) is eight stories high. Ventilation is a combination of mechanical supply by nozzles in each gallery and a natural stack effect in the atrium from bottom to top. CFD has been used for design.
Field tests and a model allowed to study contaminant concentrations in a single family home in California operating with natural ventilation or with one of six mechanical ventilation systems (cyclic or continuous, multi-point or single-point exhaust). Continuous ventilation appears to be better for contaminant levels control.
The coupled thermal/airflow simulation software CONTAM97R was used to evaluate the performance of a naturally ventilated office building recently build in Entschede (The Netherlands), for which detailed measurements results within the Natvent project had already been published.
Experiments and calculations were operated to determine air flow distribution in a test room (9.9 m2) naturally ventilated through adjustable louvers overlooking outside. Air enters at the bottom (opening surgace 0.07 m2) and is exhausted at the top of the room (opening surface 0.12 m2). Air pressure and velocities across the opening allow to estimate wind pressure coefficients. Results show in particular the influence of wind on the internal air flow. Good agreement was found between measurements and calculations.
A CFD code was used to study an office equipped with a radiant cooled ceiling and a wind-induced cross-ventilation system. Calculations covered several heights of the ceiling.
A new adaptive comfort standard is included in recently accepted revisions to ASHRAE Standard 55 - 'thermal environmental conditions for human occupancy'. The new standard allows warmer indoor temperatures for naturally ventilated buildings during summer and in warmer climate zones. The paper summarises the research carried out to formulate this new standard, presents some of the findings for naturally ventilated buildings, and discusses the standardization process. Suggests ways to use the ACS for the design, operation and evaluation of buildings and for research.
Air conditioning systems are often held to have effects upon the workforce. This research tried to assess whether continuous exposure to air-conditioning during working hours had any observable effect on health or not. A comparison was made of absence due to sickness recorded by the employers' doctors over two years in two groups of workers employed in similar jobs in the French National Electric and Gas Company in Western France. One group spent most of their time in air conditioned offices but the other worked in a natural atmosphere.
The study compared the atmospheric burden of viable particulates in the interiors of condominium homes with central air conditioning with that of the typically more open type of naturally ventilated Hawaiian residence. Enumeration of the numbers and types of respirable fungi and bacteria inside were done using Andersen microbial air samplers. To evaluate the impact of the air conditioning system on indoor air quality the results were compared with those obtained outside the homes.
In most countries nowadays, concepts of climatization and natural ventilation are considered essential aspects of any building project. However they are also used to ensure indoor air quality and summer thermal comfort. There are many other advantages to be gained such as reductions in energy use and noise levels and easier plant maintenance. In recent years, hybrid ventilation systems in office buildings have been used increasingly.
Login