AIVC - Air Infiltration and Ventilation Centre

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mechanical ventilation

Energy conservation by regulation of the central mechanical ventilation in high-rise buildings - realistic or not

Describes an investigation to see what energy saving can be achieved by the regulation of mechanical ventilation systems in high rise buildings. Measures air leakage in a block of flats, and uses a calculation model to predict the amount of energy lost due to ventilation in various situations. Concludes that the reduction of ventilation has no disadvantageous consequences for the operation of the system, and that the extracted air flow is affected more by incorrect adjustment of extractor vents then by opening windows, regardless of the setting of the ventilator.

Natural and mechanical ventilation rates in a detached house:predictions.

The results of a prediction method for calculating ventilation rates in a detached house are compared with experimental measurements described in aprevious paper. The method is capable of giving good agreement for a wide range of ventilation conditions. The need is demonstrated for further work in two important areas - the spatial distribution of background areas and the effect of turbulence.

Energy saving in buildings by control of ventilation as a function of indoor carbon dioxide concentration.

Many mechanically ventilated buildings are over-ventilated since ventilation rates are based on a fixed number of people (often in excess of the average occupancy) and no allowance is made for infiltration. States that the CO2 concentration in the ventilated space can be related to the ventilation rate per person, and by modulating the fresh air flow to maintain a constant CO2 concentration, a constant ventilation rate per person can be obtained.

Natural ventilation of auction halls in Bleiswijk, the Netherlands.

TNO Research Institute for Environmental Hygiene have developed a mathematical model (based on an electrical analogue model) for deciding on the best ventilation system (natural v. mechanical) for a building while it is still atthe design stage. This model has been applied to an auction complex situated at Bleiwijk to deduce the best ventilation system for the building. Conclusions are that a natural ventilation system can be realized by placing ventilating devices exclusively in the roof.

Is ventilation with natural draught sufficient. Ruttaako painovoimainen ilmanvaihto.

Investigations in Denmark show that there are as many as 75 different compounds in indoor air in tight houses including toluene, xylene, and radon. The dust in homes contains a large number of allergically active ingredients, the most important being the dust mite, which occurs in bed clothes.< States that good air quality is therefore difficult to maintain with natural ventilation in new tight houses. If the hygienic demands of this decade increase the need for ventilation, mechanical ventilation seems to stand a good chance.

Ventilation and temperature efficiencies of mechanical ventilation systems.

Gives measurements of the ventilation as well as the temperature efficiency of mechanical supply and exhaust systems (balanced systems). The ventilation efficiency is a measure of the performance of providing air in the occupied zone and is also an indicator of the air quality. The temperature efficiency is a measure of the system's capability of supplying heat in the occupied zone. Monitors ventilation efficiencies by adopting tracer decay techniques and the temperature efficiencies by measuring the stationary temperatures.

Measurement of the tightness of a building with its own ventilation system. Tiiviyden mittaus rakennusken omalla ilmanvachtojarjestelmalla

Shows that the leakage test in most buildings with mechanical ventilation may be performed with the ventilation system itself with only a slight reduction in the accuracy of the measurements. Using fans in the ventilation system, the pressure difference inside/outside may often reach a measurable value of 5-10 pa. If such a pressure difference is not obtained, the leakage exceeds allowable values and the building should be tightened. Before measuring, all of the supply air openings in outer core of the building should be closed and taped. All doors inside the apartment should be open.

Ventilation and heat recovery in single family dwellings: advantages in summer and winter. Ventilasjon med varmegjenvinning i enebolig fordeler bade sommer og vinter.

Reports on single family dwellings fitted with energy-saving ventilation unit. Quotes energy savings of 10,000 Kwh/annum. Points out that adequate indoor climate can be maintained through tight houses, mechanical ventilation and heat recovery as opposed to airing rooms by opening windows.

Operating experience with a residential mechanical ventilation system with heat recovery.

Assesses the efficacy of an engineered mechanical ventilation system in controlling indoor humidity in one of the HUDAC Mark XI houses. Develops a mathematical model of the home, which is used to demonstrate the interaction between outdoor humidity, infiltration and ventilation rates, and indoor moisture generation and their influence on indoor humidity levels. Discusses the operating effectiveness of the rotary heat exchanger and the energy saved through its use.

Natural and/or mechanical ventilation. Naturliche und/oder mechanische luftung.

In most office buildings, the continuous renewal of air cannot be guaranteed by means of ventilation through windows during any optional time. It is known (in the case of radiators and window ventilation) that when a window is open the ventilating heat cannot be recovered and other heat losses will occur.< The paper proves that the heating of a building by air is a greater energy saver then the conventional solution through static heating and window ventilation.