Reduce costs: efficient industrial fans in the tertiary sector
superadmin
December 26, 2016
Before going into detail about industrial fans, let's define what a fan is. According to the document recommended by the RITE, Guide to Pumps and Fans, a fan is a mechanical device used to transport air through ducts for both ventilation and air conditioning.
In the case of air conditioning systems, this transport is used to renew air (thus satisfying hygiene demand) and to condition the spaces (thus satisfying comfort demand). The primary energy used in many installations exceeds 25% of the primary energy demand of the installation. In a fan operating for a large number of hours, every kWh of electrical energy consumed requires between 2 and 3.3 kWh of primary energy. It should be noted that when trying to cool a space, the energy consumed by a fan becomes heat, which increases the thermal load of the system.
How many industrial fans are there?
There are different ways to classify fans, one of which is based on the flow direction. Thus, if the flow enters and leaves the impeller in axial direction, we are talking about axial fans or helical; if the flow enters and leaves the impeller in radial direction, we refer to centrifugal fans; and if the flow enters the impeller in axial direction and leaves the impeller in radial direction (rare), we refer to helicocentric fans.Criteria to follow when selecting the appropriate industrial fans
According to the same recommended document, when choosing a fan, aspects such as the flow and nominal pressure must be taken into account, whether the motor is single-phase or three-phase, the type of regulation (on/off regulation, regulation via 2 or 3 speeds or frequency inverter), noise, the configuration of the installation (if the space is pressurized or under-pressurized) and the fluid being transported.Measures for savings in industrial ventilation installations
We should always strive to select fans that offer maximum performance. Variable flow systems are better, from an energy-saving perspective, than constant flow systems, as they minimize the energy demand. This way, if we want to save on consumption, we should consider this aspect from the design phase of the installation.Once it is clear that the optimal system is the variable flow system, we should keep in mind that the type of regulation of the system also influences the energy consumption of the ventilation installation. Thus, regulation through a damper in series results in a practically constant power consumed by the fan and lower energy consumption than in systems without regulation. If regulation is performed through a damper in by-pass, the consumed power increases. In cases where regulation is done through a frequency inverter, the power consumed by the fan decreases significantly, making it, from the energy consumption perspective, the best regulation system.
Industrial fans, key elements in the energy efficiency of your office
There are two methods on the market to adapt controlled mechanical ventilation conditions to occupancy needs at any moment. They are two types of systems based on the fan positions:- “all or little”: the fan has two positions (presence detector)
- “proportional”: the speed of the fan adapts according to the actual occupancy (CO2 detector)
In buildings with uses different from residential, the most effective solution to limit thermal losses is to adapt the air renewal flows to the actual occupancy of the spaces.
If we want to achieve considerable energy savings, variable flow ventilation systems are recommended over constant flow systems and controlled mechanical ventilation systems that adapt to occupancy. Regarding the choice of fans, those that offer maximum performance and have a frequency variation regulation system will be selected.
Siber Ventilation
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