Wexford Science & Technology / Brown University

New Lab utilizes significant redundancy within Air-Cooled DX / Energy Recovery Rooftop DOAS

A large Laboratory development company was seeking a supplier capable of building a highly specified Dedicated Outside Air System (DOAS) air-cooled DX rooftop unit, complete with a Total Energy Recovery Wheel and multi-stage high turndown gas heat.  Dynamic Air answered that call by designing an AnnexAir unit that met the proposed challenges.

The design required 33,000 CFM of outside air, 2800 MBH of gas heat, and an enthalpy wheel that recovered nearly 90% of sensible and 80% of latent energy.

AnnexAir met those requirements using their thermo-composite no through-metal panel design that exceeds deflection rating of L/1150 at 10” TSP in accordance with SMACNA.  A burner array consisting of 6 stages of fully modulating gas heat was supplied, allowing for an impressive turndown capability of 30:1.

Finally, fan arrays utilizing ECM fan assemblies were supplied in the supply, return, and exhaust fan positions.  The use of the ECM fan arrays allowed for excellent redundancy in the case of a fan assembly failure.