How to renew the air with energy efficiency criteria: fans

Efficiently renewing the contaminated air inside a building necessarily involves extracting air from humid spaces (kitchens, bathrooms, and toilets) and introducing clean air from outside into drier areas like living rooms and bedrooms. The Technical Building Code requires the use of ventilation systems that ensure indoor air quality. For this, it is necessary to use fans (VMC units) that extract contaminated air and allow the entry of fresh air through depression or push fresh air in and evacuate stale air through pressure. These ventilation systems incorporate equipment and elements that vary depending on the type of building in which they are used, whether it be a residence, an office building, a school, or a hospital.

Types of fans (VMC) for each installation:

• Houses: the CTE HS 3 states clearly that air inside a house must circulate from dry spaces to humid ones. Therefore, bedrooms and living rooms must have intake openings, while toilets, kitchens, and bathrooms must have extraction openings. Dining rooms, bedrooms, kitchens, and living rooms must have a complementary natural ventilation system. Ventilation systems capable of providing thermal comfort efficiently, that is, with maximum energy savings, are especially recommended. For this purpose, in winter, it is necessary to recover the heat from the stale air extracted from the house, thanks to the intervention of heat exchangers that maintain a constant indoor temperature. In summer, the new air entering the house is cooled with the stale air that is extracted thanks to the intervention of these exchangers.

• Schools: children are more sensitive than adults when breathing contaminated air, as they inhale a larger volume of air compared to their body weight. Therefore, the RITE requires a ventilation system for classrooms in schools. In this type of building, it is particularly important to adapt the air renewal rates to the actual occupancy of the spaces to achieve efficient operation of the installation. Presence detectors can be used to achieve energy savings close to 35% in air renewal rates. CO2 sensors can also be very useful as they provide very high energy savings, close to 70%.

• Offices: the ventilation of an office building has a significant impact as it directly affects the health and productivity of workers. The World Health Organization (WHO) emphasizes this insistently. Consequently, there is an increasing demand for the construction of smart buildings, which are those capable of being healthy and environmentally friendly while also being managed sustainably. Improving indoor air quality often conflicts with energy efficiency, as it is usually related to an increase in the ventilation rate (volume of air supplied from outside). In office buildings, both objectives can be achieved by using monitoring technologies capable of ensuring quality indoor air at very low operating costs.

• Hospitals: this type requires special care in air treatment to guarantee the health of its users. The risks derived from excessive contaminated air in these centers are varied, ranging from the occurrence of infections such as nosocomial infections to outbreaks of tuberculosis. When designing and installing ventilation systems in a hospital, air sterilization treatments with UVGI emitters in operating rooms, fan-coils, air handlers, and ducted air conditioning systems are necessary. Additionally, active polarization filters help save energy in electricity consumption and reduce maintenance costs.