Dual wheel DOAS

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Hi All,
Has anyone modeled a dedicated outdoor air system with an enthalpy wheel
and passive desiccant wheel similar to the attached?

Thanks,
Tom

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Hi Tom,
The new DOAS system in eQUEST has cooling, heating and dehumidification capabilities, but can only simulate one wheel. The presentation by Doug Maddox provides several examples of inputs to use for different configurations. You would need to use some sort of workaround to model the passive dehumidification wheel in a dual wheel DOAS. A couple ideas:

* Model the energy recovery effectiveness of the total energy wheel only, but include the static pressure fan power penalty of both wheels. Simulate the reheat effect of the second wheel by adding an electric or furnace HEAT-SOURCE at the DOAS, and assign a new meter for the DOAS heating so you can manually subtract the heating energy.
* Model the energy recovery effectiveness of the total energy wheel only, but include the static pressure fan power penalty of both wheels. Simulate and record the DOAS cooling energy. Then model the combined energy recovery effectiveness of the dual wheels with high values of ERV-SENSIBLE-EFF and ERV-LATENT-EFF, and reduce the cooling efficiency iteratively to match the correct cooling energy. (I expect the cooling energy would decrease when you use the combined effectiveness of the dual wheels, since the wheels are upstream of the cooling coil in the simulation.)
You can also reach out to Pinnacle and ask them for recommendations on how to capture the energy savings of their DOAS in eQUEST?

Regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer

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Bill Bishop's picture
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I know it is an eQuest form but Trane TRACE can do dual recovery wheel systems including the alternative desiccants. Search ?How do I model cool dry quiet desiccant wheels (CDQ) in TRACE 700? ?
Bill ? Thanks for the interesting thoughts on work arounds in eQuest.

Paul Riemer, PE, LEED AP BD+C
DUNHAM

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