Whether it is from the National Building Code, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) or the regulations on health and safety at work, they all specify that a mechanical ventilation system installed in a facility must be able to provide the minimum amount of fresh air changes per hour established according to the category or the nature of the building. When we talk about an air change, we mean rejecting air outside to the benefit of an addition of fresh air. The exhaust air has been conditioned (heated, conditioned or humidified) while the new fresh air will have to go through the same process.
The number of changes established by regulation can vary from 1 to 4 per hour, depending on the nature of the building. It doesn’t necessarily mean that these minimal air changes are always required. Depending on the situation, it is possible to measure the air quality and make air changes only when it is necessary.
Depending on whether we consider a commercial or an industrial building, heat exchangers can also reduce heating costs by recovering some of the heat from the building’s air exhausted to preheat the incoming air. The heat exchanger is designed to make sure that air from inside never contaminates air from outside. Only heat is exchanged. Any good unit design should also consider the possibility of frost formation on the exhaust air side during winter temperature.
The exchanger’s choice depends on several economic and technical factors and must be combined with a simple and effective control system to ensure optimal operation. A short visit of your facilities will allow the energy team to propose the best energy saving project and take account of your specific needs.