Preheat hours usage

lvidal · Posts: 69 Location: Paris

Hi Andy, Hi Steve.

I'm trying to evaluate a winter consumption of class room building and impact of a boiler scheduler and insulation.
DesignBuilder show me all its power ! In half an hour, the building model was design and energy consumption known for each case. Keep on going !

By the way, I wanted to use the preheat hrs parameter set in HAVC template. But I don't see boiler starting before the occupancy start time.
How does it work ?

Context :
timing: 7/12, HAVC : simple or compact (I tried the both), HAVC schedule: 8-18h Mon-Fri, Occupancy: 8-18h Mon-Fri, HAVC and Nat Ventilation with occupancy option: off.

Best regards,
Laurent

Andy Tindale · Posts: 1165 Location: Stroud

Hi Laurant,

Glad to hear you are finding DesignBuilder is an effective way for modelling schools Smile

The way preheat works depends on the settings on the Model options dialog. If you are using the 'Typical workday' option and HVAC operation is the same as occupancy ('HVAC + natural ventilation operates with occupancy' option is set), then the preheat period on the HVAC tab is used to add an additional hour prior to occupancy. Otherwise, if HVAC operation is defined explicitly then the preheat data is not visible in the Model Data and the '7/12 schedule' or 'Typical workday' schedule is used directly as set.

Please be aware that any settings in the template data do not affect the model until they are loaded.

I hope this answers it.

Regards
Andy

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