Cooling load design tool for UFAD

Cooling load design tool for Underfloor air distribution (UFAD) is developed focused on accounting for the differences between standard overhead (OH) mixing systems and UFAD systems. Transformations were developed by conducting design-day, EnergyPlus simulations, which performs a fundamental heat balance calculation and contains UFAD-specific algorithms that are validated based on extensive laboratory testing. A spreadsheet-based calculation procedure is developed that allows the user to select from different plenum configurations that represent a range of design practice. The design tool predicts the room air temperature profile based on the fraction of the cooling load assigned to the room, room setpoint temperature, the type and number of diffusers, diffuser discharge temperature, and calculated airflow rate. The results show that the reverse series plenum delivers cooler air to the perimeter, resulting in a reduction in airflow of nearly 50%, with increased stratification.