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Fresh air, less power

Optimised ventilation systems in houses can save up to 75 per cent energy


Cooking, washing and even just living are constant sources of moisture and CO2 in the home. The atmosphere and well-being of the residents can be improved by the use of a controlled mechanical ventilation system to ensure fresh air circulation around the clock. Such an installation extracts odours and moisture which could otherwise promote the formation of mould, and damage the structure of the building.

Since 1969, hundreds of thousands of type R2E190 and R2E140 fans have been fitted in this sort of system in France. For a 4-room house, these systems have a power consumption of around 35 WTh-C (WTh-C = Average consumption for one hour at high speed and 23 hours at low speed). The total throughput is between 200 and 250 m³/h. This type of system is extremely efficient, but the power consumption cannot be disregarded in view of rising electricity prices.

Exhaust air box by Aldes

Exhaust air box by Aldes. The centrifugal fan used in this product is driven by an energy-saving motor

There are two possible ways of cutting the power consumption Reducing the power consumption of the actual fan and regulating the fan throughput on the basis of how the room is used. By employing EC fans and in particular motors of the ESM (R1G160) type, a considerably lower power consumption can be achieved. Energy consumption can also be reduced by the use of throughput control based on room utilisation. Whenever rooms are not in use and the impact level is low, there is little need to extract air. With conventional systems, users can regulate the air throughput as required by means of a switch. In modern systems, the air throughput is adapted as a function of the moisture content of the air withdrawn by gradually opening the extractor vents (reduction of pressure loss by integrated sensor).

The use of EC fans and throughput control based on room utilisation makes it possible to achieve a power consumption of roughly eight WTh-C. In other words, consumption can be reduced by nearly 75 per cent as compared to a standard system. This also has a beneficial effect on heating costs, as the system helps to improve the energy performance of a building. Heating costs can be cut by 10 to 15 per cent in this way.
Even more advanced systems have the capacity to recover the heat contained in the extracted air to warm up the air on the supply side. The use of a heat exchanger does however result in greater pressure losses. A fan of type R3G140 is therefore employed. This principle fully satisfies Directive 2009/125/EC of the European parliament, which aims to both increase energy efficiency and reduce greenhouse effects by 20 per cent. 

The priciple

EntlueftungsprinzipAn encased fan, usually installed on the top floor, is connected by way of a duct system to extractor vents fitted in the rooms affected, i.e. with damp conditions, such as the bathroom, toilet and kitchen. The pressure in these rooms is then a few Pa lower than outside. The fresh air flowing in from outside is conveyed via air inlets into the “unaffected” rooms, such as bedrooms, living room and dining room.

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