# [Bldg-sim] DOE2.1E questions

Varkie Thomas Varkie.Thomas at som.com
Tue Aug 27 12:13:50 PDT 2002

```These are DOE2.1E questions

Outdoor Air (OA) Control :

The Supply Air (SA) of a VAVS can vary due to varying envelope, lights
and receptacle loads but the occupancy load can be fixed.  So the
minimum OA quantity must be fixed for VAVS based on peak zone
occupancies or by user override. So how would you vary the OA quantity
based on occupancy (using CO2 Sensors in Return Air) independently of
the VAV Supply Air quantity?

Under-Floor Air Supply :

How can underfloor air supply be simulated in DOE2.1E?  Since the space
above 7 feet does not have to be maintained at 75 in summer or 72 in
winter, the weighted average temp of the two layers (below and above 7
feet) can be used.  How would you adjust the temp of the space above 7
feet be when the outdoor air temp varies from 0 to 100?

Section 6.1.3.3 (Ventilation Effectiveness Ev) in ASHRAE Std 62 says
that the ventilation rates in the tables can be reduced depending on the
effectiveness of the air supply, return and exhaust systems.  The
effectiveness of ventilation with under-floor supply is better than
ceiling supply.  What is the procedure for reducing the ventilation rate
for under-floor supply relative to ceiling supply?

Hotel/Apartment HVAC :

An apartment in a high-rise building can be served simultaneously, using
different operating profiles, by fan-coil units, outside air supply
systems, toilet, kitchen and dryer exhausts and transfer make-up air
from the corridor. There can be heat recovery between one or more of
these separate exhaust systems and the outdoor air system.

An direct OA system to the space is not possible since, in DOE2.1E, the
space can only be served by one system (FCU in this case).  So the OA to
the rooms is transferred from the 100% OA system serving the corridor.
At the moment we find the weghted average (fraction) of all the exhaust
systems and transfer OA from the Corridor's 100% OA System.  Is there
another way for modelling apartments and hotel rooms with DOE2.1E?

Varkie Thomas
Skidmore, Owings & Merrill
224 S. Michigan Ave.
Chicago, IL 60604
Tel: 312-360-4467 (direct)
Fax: 312-360-4545
Email: varkie.thomas at som.com

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