Increasing the energy efficiency of fan systems by using outlet diffuser

This work represents a method for quantitative evaluation of a fan system energy efficiency increase in case a diffuser is installed at the end of the discharge pipe (fan system outlet). It is indicated that the saved energy increases rapidly when the diffuser extension rate is increased up to 3.0. ..3.5 and then the growth rate starts to decrease. The diffuser angle has less impact on the energy consumption decrease compared to the previous mentioned parameter, as for higher values of (diffuser rate) extension the expressing of the energy efficiency decrease is more intensive. The effectiveness of using outlet diffuser is better for ensuring a high system flow rate, as well as in case of providing a small cross-section area of the discharge pipe (system outlet), which is due to the greater energy saving by its absolute value.