The rise in energy-efficient building designs is increasing the need for building ventilation systems.
Energy efficient buildings require more insulation to reduce heating and cooling loss. This means that the air inside your building lingers longer and becomes stale. The stale air also puts your building at a greater risk for allergies, residual odours, condensation, mould and more.
Ducted AHU installations are mainly used in larger building applications and generally provide tempered fresh air to various rooms. The incoming fresh air is filtered then heated or cooled as necessary prior to being supplied to the space. The AHU’s are usually located in a plant room. One of the benefits of this type of system is that all the maintenance required is carried out from within the plant room and not within the space being conditioned. The extract air is removed from the space using a separate fan system; this system can remove air from a ceiling void or be connected to grilles in the ceiling via ductwork. As the air is not recirculated.
This type of system is similar to the previous example except that the extract air and fresh air are put through a form of heat exchanger prior to being exhausted and discharged into the space. In winter the warm air being extracted from the space heats the heat exchanger, this in turn heats the cooler fresh air being supplied back into the space, in summer the same principle acts in reverse. This type of system will provide cost savings to the previous type as the amount of energy being used to pre heat or cool the incoming fresh air is reduced. The AHU’s can be manufactured to suit any application from domestic to commercial. Both Daikin and Mitsubishi provide an internal ducted heat recovery fan coil unit which can communicate with their respective heat pump systems installed providing a packaged economic highly efficient HVAC installation.
We have previously described the function of a package type system, apart from being able to supply heated or cooled air, the systems we install have an option of an economiser, and this acts as a mixing box and joins the fresh air to the recirculated air via motorised dampers. The fresh air dampers can be adjusted to always provide a minimum amount of fresh air based on the occupancy of the space being conditioned, this eliminates the need for a separate ventilation system, the fresh air dampers are modulated using either dry bulb temperature or enthalpy control.
Elliott’s has considerable experience designing and installing Ventilation systems for many types of buildings.