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[EnergyPlus_Support] Terminal Reheat System controls

Dear EPlus Forum,

For your general information and (hopefully) benefit:
E+ essentially ignores the Cooling setpoint (SP) for reheat systems
when  in the setback / setup mode.  Instead, it uses the Heating SP. 
The logic behind this is that reheat systems use MORE energy to
maintain a higher SP, so no one will really want to control their
reheat system to a higher unoccupied SP.
In order, however, to get realistic results, I recommend that you
consider comfort and practical issues when establishing the Heating SP
schedule.  For example, if a normal SP scheme is to use 20C for the
occupied Heating SP, and 25C for Cooling SP, you are likely to have
unhappy occupants in the Summer when they find that the room
temperature is 20C on a mild (non-design) day!  Most people do not
like to walk in from 35C to a 20C room -- too much change.
For this reason, I have revised my Heating SP schedule to use a higher
SP (e.g., 22C) in the Summer and lower (e.g., 20C) in the Winter.  As
a practical matter, check to see whether the control system actually
uses setpoints in the same way as E+; then make E+ mimic the real system!

Development Team, I am hoping that this information can be added to
the User Reference.

Finally, for those of you running Energy Analysis for LEED
certification, the Set Point Manager: NightCycle "on/off tolerance"
setting can add a LOT of hours to the "unmet loads" report if you set
it too high.  Apparently E+ considers a load "unmet" if the zone temp
is more than 0.2C apart from the SP.  Therefore, making the "on/off
tolerance" higher than .2C runs the risk of dramatically increasing
the number of hours E+ considers for an "unmet load".

Hope this was helpful!



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