Re: [EnergyPlus_Support] purchased hot water energy for two systems

["Michael J. Witte" <mjwitte@xxxxxxxx>]

Are the zone mean air temperatures identical in both runs?  My guess is that 
one of the systems is not meeting the zone setpoint which would explain why the 
amount of heating energy is different.  Specific variables you should be 
looking at to understand what is happening are:

Zone/Sys Sensible Heating Rate
Zone/Sys Sensible Cooling Rate
Zone/Sys Air Temp
Baseboard Heating Rate
Total Water Heating Coil Rate
Plant Loop Heating Demand
Purchased Hot Water Rate
Pump Heat To Fluid

(or the energy equivalent of each of these).

The yahoo list does not accept attachments, so I cannot see your input or 
results.  If you cannot find the problem, either upload the file(s) to the 
files area in the yahoo group or send as a zipped attachment to energyplus-
support@xxxxxxxx.

Mike


On 6 Aug 2004, at 12:37, Meng Zhang wrote:

> It seems that in winter time, reheat coil picks up the heating load. As you
> said, reheat coil also prevent overcooling.  However my simulation results show
> that the baseboard heater spend more energy in Oct & Nov than reheat coil. In
> Dec and Jan, they are pretty same. I attached the file, could you help me have a
> look?
> 
> BTW, which output parameter can show how much heating and cooling energy it
> spend for each zone,  baseboard heating energy or what else?
> 
> 
> Alan
> 
> Fred Buhl <wfbuhl@xxxxxxx> wrote:
> The 2 heating components are controlled differently. Right now the 
> reheat coil operates
> during cooling to prevent overcooling. This is a subject of debate as to 
> whether this is what
> we want to be doing.. The baseboard only meets the heating load - so it 
> is a truer reflection
> of the zone heating requirements.
> 
> Fred Buhl
> 
> pizzaalan wrote:
> 
> >Dear all,
> >
> >I simulated a building equipped with VAV system and reheat coil.  
> >Then I tried to use baseboard heater instead of reheat coil in all 
> >the perimeter zones.  The purchased hot water energy results for 
> >these two systems are different.  The purchased hot water is the 
> >only heating source for these two systems, and all the set points, 
> >schedules, location and constructions are same.  The purchased how 
> >water energy is supposed to represent heating load, right? Why are 
> >they different for these two systems?  Does baseboard heater have 
> >different heat transfer algorithm with reheat coil? 
> >
> >Thanks.
> >
> >Alan
> >
> >
> >
> >
> >The primary EnergyPlus web site is found at:
> >http://www.energyplus.gov
> >
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> >
> >Attachments are not allowed -- please post any files to the appropriate folder
> >in the Files area of the Support Web Site.
> > 
> >Yahoo! Groups Links
> >
> >
> >
> > 
> >
> >  
> >
> 
> 
> 
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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