TA-23-C012 – Energy and Cost Assessment of The Proposed Dual VAV System

Heating, ventilation, and air conditioning (HVAC) systems consume more than half of the building’s total energy use, hence energy-saving strategies for these systems have been a prime objective for policies and building standards. A new configuration of the dual duct system called the “Dual VAV” system has been proposed to maximize the energy benefits of typical VAV systems while limiting their shortcomings. This research considers the cost of the proposed system to establish its feasibility to be implemented widely. The study focuses on the energy and cost assessment of the proposed dual VAV systems in different climate zones to evaluate their performance compared to other conventional VAV systems. For the initial cost analysis, the components of the dual VAV system are sized in a case study building and the upfront cost is calculated according to the current estimates from local vendors and the national average. This establishes the design process of the new dual VAV system as well as demonstrates how the component sizes can be smaller than existing dual duct systems. In addition to that, a simulation study is conducted with a sequence of control for the dual VAV system to assess the annual energy consumption. Operational cost is then calculated with current utility rates by using the simulation study results for all the systems. The results show that, when the initial cost of a dual VAV system is considered, it is higher than single duct VAV systems but lower than traditional dual duct systems. However, when the operational cost is considered, the dual VAV system generates up to 24.52% savings compared to the other typical systems in different locations due to the reduced energy consumption The results of the study demonstrate the cost benefits of the improved dual VAV systems and their viability to be implemented in buildings from both energy and economic perspectives.