Energy and economic analysis of model-based air dampers strategies on a VAV system

Abstract

A variable air volume (VAV) air handling system can significantly reduce fan power under partial load conditions. The focus of this study is developing a modeling program to predict the potential energy saving by the secondary HVAC system strategies. Comprehensive steady-state models are established to describe the energy performance of different control strategies for secondary HVAC systems. With building loads, minimum fresh air flow rate, pressure losses, supply air temperature control, dampers control and coil characteristic as inputs, the objectives were to develop a simulation model to evaluate performance of an air handling system. The potential energy savings of constant air volume (CAV) and VAV strategies are investigated in a representative residential building. The simulation results show that about 13% of electrical power can be saved by the proposed VAV strategy in respect of the CAV. Also, life cycle cost analysis is applied on the considered system. It is found that VAV system is not economically good for the considered building because of low electricity price in Iran. Finally, a sensitivity analysis was conducted to demonstrate how the electricity price affects the economic performance of the VAV system.