The aim of a ductnetwork

The aim of a ductnetwork is to distribute air to the building within the parameters originally foreseen for the project,including temperature and humidity.Air atthe machine exithas differenttemperature and humidity characteristics to those of the surroundings,which is why unwanted heat transfer through the duct’s walls will always occur.The thinner the duct’s insulation,the greater the heat transfer.
Energy losses caused by air leakage atductwork joints also has to be added to thatvia heattransfer.
These two effects are illustrated by the data in the “Air ductperformance and costcomparison”table (reference NAIMA AH 109).This table presents the results of a test carried out by NAIMA (North America Insulation Manufacturers Association) on the energy losses in differenttypes of HVAC ducts,for the following conditions:
Ductwork 20mlong Cross section:40cm x 20cm Temperature inside the duct:15ºC Temperature outside the duct:25ºC
With reference to this table,if a non-insulated duct is assumed to be the worst case scenario for thermal loss and,therefore a benchmark for the highest energy loss,it is strikingly apparent that glass wool ductboards equate to massive energy savings