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[EnergyPlus_Support] Re: A problem of Sensible Heating/Cooling Rate

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: A problem of Sensible Heating/Cooling Rate
From: "hbn_pch" <hbn_pch@xxxxxxxxxxxx>
Date: Thu, 11 Nov 2004 06:47:37 -0000
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Dear:
  Thank you very much,Mike!!!With your help,i have solve these 
problems.
  I run the simulation in version 1.2.0,so i use the document in the 
same version too.(^_^)
  Thanks again!!!
  pch  


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
<mjwitte@g...> wrote:
> What version are you running?  These definitions were added in 
v1.2.1.
> 
> On 10 Nov 2004, at 13:34, Michael J. Witte wrote:
> 
> > 
> > 0.  Definitions of these variables appear beginning on p. 180 
(pdf p. 210) of
> > the Input Output Reference.  I will admit the definitions are 
quite brief. The
> > answers to the remaining questions can all be explained by 
reviewing the zone
> > thermostat setpoint, zone temperatures, and system supply air 
temperatures.
> > 
> > 1. No.  On this day, the system fan is on for all hours with some 
amount of
> > outside air at all times (smaller at night), the zone heating 
setpoint is 12.8C
> > at night and switches to 21.1C at hour 8, the maint heating coil 
is controlled
> > to supply 16C supply air.  The zone temperature in the early 
morning is floating
> > between 15.7 and 16.2C, and some fraction of lights and equipment 
are always on
> > adding heat to the space.  Whenever the zone is >16C, this 
variable will report
> > cooling; <16C heating.
> > 
> > 2.  At hour 8, the thermostat setpoint increases to 21.1C, so the 
heating 
> > delivered is large to recover from setback.
> > 
> > 3.  It is not simultaneous at the HVAC system time step.  The 
values reported in
> > the example are averaged or summed over the zone time step which 
may contain
> > multiple system time steps.  As explained before, you must report 
these
> > variables at the "detailed" reporting frequency to see every HVAC 
system time
> > step.  
> > 
> > 4.  The zone is floating down to the setback temperature while 
the system 
> > continues to supply minimum flow at 16C.  If the zone is >16C, 
the system is
> > cooling the space by default until the thermostat calls for heat 
to maintain the
> > setback temperature.
> > 
> > Mike
> > 
> > 
> > On 9 Nov 2004, at 2:47, hbn_pch wrote:
> > 
> > > 
> > > 
> > > Dear all:
> > >   Thanks for Mike's kind reply.
> > >   I have searched the document and find it just lists the name 
of the 
> > > variables.There is no specification in the document.
> > >   For convenience,I list the values for the whole day in 
14th,Jan.
> > > I use Space-1 for instance.From 1am to 7am,the Zone/Sys Cooling 
Rate 
> > > values are:210w,217w,220w,215w,218w,219w,208w.The Zone/Sys 
Heating 
> > > Rate values are 0.At 8am,The Zone/Sys Heating Rate value is 
2519w,and 
> > > the Zone/Sys Cooling Rate is 0.At 9am,The Zone/Sys Heating Rate 
value 
> > > is 167w and the Zone/Sys Cooling Rate  value is 62 w.For the 
remainer
> > > hour,the Zone/Sys Cooling Rate value 
> > > 
are:517w,558w,574w,525w,550w,591w,573w,546w,542w,457w,381w,318w,270w,2
> > > 29w,217w,0w.And The Zone/Sys Heating Rate value is 0.
> > >   Then problems come:
> > > Problem 1:Why there is only Zone/Sys Cooling Rate during 1am to 
7am?  
> > > And during 1am to 7am,the Zone/sys Air Temp values increase a 
little 
> > > sometimes,if the Zone/sys Air Temp increase,The Zone/sys 
Heating Rate 
> > > value must be positive?
> > > 
> > > Problem 2:Why the the Zone/Sys Heating value is so big?
> > > 
> > > Problem 3:Why the the Zone/Sys Heating and The Zone/Sys Cooling 
Rate 
> > > exist simultaneous and the values is so small?
> > > 
> > > Problem 4:Why there is only Zone/Sys Cooling Rate during the 
remainer 
> > > hours.And in front hours of the remain,the system is on its 
occpuied 
> > > period,but the Zone/Sys Heating Rate value is 0.Why?
> > > 
> > >   Thanks for all your kind help!
> > >   pch
> > > 
> > > 
> > > 
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
> > > <mjwitte@g...> wrote:
> > > > The Zone/Sys Heating/Cooling report variables are described 
in the 
> > > Input Output 
> > > > Reference, as are most report variables.  Search the docment 
for 
> > > the variable 
> > > > name to find a description.
> > > > 
> > > > In this simulation, the thermostat has a setback schedule, so 
that 
> > > is why the 
> > > > zone temperatures are cool in the unoccupied period.  Also, 
during 
> > > winter, the 
> > > > system has been scheduled to run the fan around the clock.  
The 
> > > minimum outside 
> > > > air schedules is set to 2% during unoccupied hours, so the 
system 
> > > always brings 
> > > > in some fresh air.  During the hours that you refer to that 
show 
> > > values for 
> > > > Zone/Sys Sensible Cooling, the system is cooling the space 
because 
> > > the mixed 
> > > > air is cooler than the zone air.  Remember that the zone/sys 
> > > heating/cooling 
> > > > variables indicate what the system delivered to the zone, not 
what 
> > > the coils 
> > > > are doing.
> > > > 
> > > > Mike
> > > > 
> > > > 
> > > > On 5 Nov 2004, at 3:09, hbn_pch wrote:
> > > > 
> > > > > 
> > > > > 
> > > > > Dear all:
> > > > >   I start a simulation of the example of 5ZoneEngChill.idf 
> > > attached 
> > > > > to the EnergyPlus.
> > > > >   For analysis,I add a boiler parameter of Boiler Gas 
Consumption 
> > > > > Rate in the report parameter.I discover that there is only 
> > > Sensible 
> > > > > Cooling Rate values from 1am to the 7am.But at 8am there is 
only 
> > > > > Sensible Heating Rate values,and these values are very 
> > > big.Whereas,in 
> > > > > 9am,Sensible Cooling Rate value and Sensible Heating Rate 
value 
> > > exist 
> > > > > simultaneous and the two values are very small.For 
remainder 
> > > > > hours,there is Sensible Cooling Rate only.
> > > > >   From 1am to 7am,the Zone/Sys Air Temp values are 
approximately 
> > > > > 17C,and from 8am to 6pm the Zone/Sys Air Temp values are 
> > > > > approximately 21C.Then the Zone/Sys Air Temp values 
decrease by 
> > > hour.
> > > > >   So I'm puzzled.I can't find the reasonable explain.I even 
did't 
> > > > > know what do Zone/Sys Heating/Cooling Rate and Zone/Sys Air 
Temp 
> > > mean.
> > > > > 
> > > > >   Thanks for all your kind help!
> > > > >   pch
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > The primary EnergyPlus web site is found at:
> > > > > http://www.energyplus.gov
> > > > > 
> > > > > The group web site is:
> > > > > http://groups.yahoo.com/group/EnergyPlus_Support/
> > > > > 
> > > > > Attachments are not allowed -- please post any files to the 
> > > appropriate folder
> > > > > in the Files area of the Support Web Site.
> > > > > 
> > > > > Yahoo! Groups Links
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > 
> > > > 
> > > > 
> > > > ========================================================
> > > > Michael J. Witte, GARD Analytics, Inc.
> > > > EnergyPlus Testing and Support      
> > > > EnergyPlus-Support@g...
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > The primary EnergyPlus web site is found at:
> > > http://www.energyplus.gov
> > > 
> > > The group web site is:
> > > http://groups.yahoo.com/group/EnergyPlus_Support/
> > > 
> > > Attachments are not allowed -- please post any files to the 
appropriate folder
> > > in the Files area of the Support Web Site.
> > > 
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support      
> > EnergyPlus-Support@g...
> > 
> > 
> > 
> > 
> > 
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> > 
> > The group web site is:
> > http://groups.yahoo.com/group/EnergyPlus_Support/
> > 
> > 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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References:
- Re: [EnergyPlus_Support] Re: A problem of Sensible Heating/Cooling Rate
  - From: Michael J. Witte

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