What is Direct, Zone-Specific, Demand Controlled Ventilation?

a) Direct: Ventilation units are placed as close as possible to where they are needed, usually within the room to be served.

Airmaster

b) Zone-specific:

Each room or zone is given the appropriate level of ventilation, completely independently of what may be happening elsewhere in the same building. It would be possible, for example, for a demand controlled ventilation unit to be stopped temporarily even though adjacent rooms may be experiencing high demand.

c) Demand Controlled:

Demand control is defined as the linking of fan speed with one of the indicators of indoor air quality or occupancy. Sensors are used to measure or detect changes in either CO2 concentration, movement as detected by PIR sensor or humidity level. For example, with increase in measured room CO2 level, a corresponding increase in fan speed would introduce a higher flow of fresh air, thus helping to bring CO2 level back down again. The potential for energy saving is excellent.

Because they are placed within the room to be controlled, great care has been taken with the casing design of AirMaster air handling units. They are segmented horizontally so as to blend in unobtrusively with ceiling lines. They can be mounted so as to be fully visible or partly recessed in the ceiling void.

Demand Controlled Ventilation Ensures Energy Savings and High Indoor Air Quality

SAV Systems’ AirMasters aim to provide consistently good indoor air quality over the long term. Although this objective is easily stated and understood, it can be challenging to achieve in practice. Here are some of the issues which make the difference:

1. Heat Exchanger Design. The aluminium contraflow heat exchangers utilised by the AirMaster air handling units have excellent conductivity, which enables the air pathway openings to be sized generously. Any condensate formed within the exchanger extract pathways runs out rapidly to the collection tray, leaving the air pathways clear even at low temperatures. Condensate is dispersed by evaporation into the extract air flow.

2. Good quality air filtration. This feature is important, not only to removing contaminants from incoming air, but also to maintaining the cleanliness of the heat exchanger surfaces. AirMaster units are equipped with M5 filters as standard, which keep the heat exchangers working efficiently. Where a higher level of contaminant removal is required (eg, for medical surgeries), F7 filters can be provided instead.

3. Effective noise control. Noise can seriously detract from user experience. As direct ventilation units are in the same room as the occupants they serve, keeping noise emissions under control is crucial. AirMaster units emit only 35dB(A) at 1m at full throughput. Where external noise is potentially an issue, their attenuation of 49dB is sufficient to neutralise whatever noise attempts to come in through the air pathways.

AirMaster air handling units can be adapted in many different ways. They can be:

  • Fully exposed below the soffit, or recessed (1/3 or 2/3) in the ceiling void.
  • Placed against an external wall or connected to this by up to 8m ducting.
  • Floor mounted for either mixing or displacement ventilation. The sides can be used as partitions, notice boards or sound absorbent barriers.
  • Arranged for modulating control of CO₂ level or humidity. Alternatively, PIR displacement sensors can be used instead.

The importance of indoor air quality

Inadequate ventilation can lead to uncomfortable build-ups of heat and carbon dioxide from occupants and equipment. Once carbon dioxide levels exceed 2,000 ppm, physical effects such as drowsiness and  impaired concentration become apparent. Efficient ventilation produces good indoor air quality, which in turn enables improved concentration, alertness and a sense of wellbeing.

SAV are happy to provide guidance for any application. With over 45,000 AirMaster demand controlled ventilation air handling units currently in service throughout the EU, there is a wealth of experience to draw on. Whether for retrofits or new build projects, SAV can offer a view on good ventilation options for you to consider. Whatever level of project information is available to you, do get in touch to see how AirMaster might be able to help. We take pride in our practical, hands-on approach and technical support.

For further information on heat recovery ventilation systems, please contact us:

By phone:
01483 771910
By e-mail: webenquiries@sav-systems.com

We look forward to hearing from you!

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  • 1. AirMaster Brochure
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