Types of fans, how to select the right one?

According to Article 12. Energy efficiency of the Regulation of Thermal Installations in Buildings (RITE), "thermal installations must be designed, calculated, executed, maintained, and used in such a way as to reduce the conventional energy consumption of thermal installations and, consequently, greenhouse gas emissions and other air pollutants, by using energy-efficient systems, systems that allow for energy recovery, and the use of renewable energies and residual energies". To achieve this, any system intended for the circulation and conduction of fluids must be chosen so that its performance, regardless of its operating state, is maximized. There are different types of fans on the market. Do you know the criteria for their correct selection?

Selection

When selecting a fan, we must consider the following factors:

u2022 The necessary ventilation flow (Q), expressed in m3/h, for the proper renewal of air.

u2022 The required pressure.

u2022 The tolerable noise level.

To determine the necessary flow, we must consider the use of the room to be ventilated, occupancy, or pollution levels. The current regulation for ventilation in homes is the Technical Building Code. In the chapter dedicated to air quality, CTE DB HS 3, the minimum required admission and extraction flows for each room in homes are established.

Ventilation, efficiency, and sustainability

It should be noted that the circulation of air through the ductwork of ventilation systems causes load losses, i.e. energy losses. The load losses of fans can be due to the length of ducts, their section, air friction, elbows and changes of section, the presence of obstacles, dust accumulation, etc. Therefore, it is crucial that our ventilation system is a controlled and airtight system, so that energy expenditure is minimized.

Types of fans: classification

According to different types of classification, the types of fans available on the market are as follows:

According to the starting system

u2022 Direct. The motor coincides with the axis of the impeller or blades of the fan.

u2022 By transmission. The motor is separated from the air flow and the transmission occurs via belts and pulleys.

According to the airflow path

u2022 Centrifugal. The airflow circulates radially.

u2022 Axial. The airflow circulates axially.

u2022 Transverse. The airflow circulates perpendicular to the tangential direction, both at entry and exit.

u2022 Helicoidal. Air enters axially and exits radially.

According to their function

u2022 Enclosed fans. They usually have a tubular shape and move air through a duct.

u2022 Wall fans. Move air from one face of a wall to the other face of the same wall.

u2022 Jet fans. Those that project a flow of air onto a surface or a person.

According to operating characteristics

u2022 Standard. For slightly polluted air.

u2022 Special. For characteristic air (humid, polluted, hot...).

According to pressure

u2022 Low pressure.

u2022 Medium pressure.

u2022 High pressure.

According to control of performance

u2022 Variable speed, flow modification, etc.