[Bldg-sim] Cooling Load in EnergyPlus
Ery Djunaedy
ery.mailinglist at gmail.com
Fri Mar 4 09:26:08 PST 2011
Sandeep,
This is what I call a legacy topic from the DOE2 era. You better search
the posts in EnergyPlus support mailing list. Search for "cooling load
component", and you will find an interesting discussion.
In summary, you will not find a cooling load component report in
EnergyPlus nicely formatted a-la LS-C report in eQuest/DOE2.
If you try to match the total gains v.s. the cooling load for every time
step, then you will be in for a long ride. Take the solar radiation
gain, for example. The GAIN for a particular time step is not
necessarily converted into cooling LOAD at the next time step. If your
building is thermally massive, then the delay plays an important role
and it could be hours before the solar radiation GAIN becomes an actual
LOAD as seen by the thermostat. Do not forget about this, if you try to
match the cooling load report with the total gains.
If you are talking about peak cooling load, then you will need to focus
on the zone sizing report. Calculating the gains component is easy
because the schedule is always 100% on. You just need to quantify the
ventilation load.
Please note that the report suggested by Paul below is the convection
report. I imagine that you would expect a conduction report? EnergyPlus
zones technically cannot see conduction through opaque surfaces, in the
sense of A*U*DeltaT. They can only see convection and radiation. In
fact, if you try to match A*U*DeltaT for external wall with this report
(Surface Int Convection Heat Rate) then you will have a hard time
explaining. If you keep this in mind, the differences can be easily
explained.
Cheeers,
Ery
On 03/04/2011 07:07 AM, Paul Raftery wrote:
> Hi Sandeep,
>
> A full list of the available output variables are given in the .rdd
> file (it is one of the files output from the simulation). Simply copy
> the relevant line from that file into your .idf (or .imf) file, rerun
> the simulation, and the new variable(s) will be output to the .csv and
> .eso files.
>
> e.g. Adding this line to the input file will give you the convective
> heat gain from all interior surfaces in your model.
> Output:Variable,*,Surface Int Convection Heat Rate,hourly; !- Zone
> Average [W]
>
> Regards,
> Paul
>
> On 4 March 2011 13:50, Sandeep Kachhawa <sandeep.kachhawa at gmail.com
> <mailto:sandeep.kachhawa at gmail.com>> wrote:
>
> Dear All
> Can we get the individual break-up of cooling load in
> *EnergyPlus*? Internal loads (People, Equipment & Lighting),
> Infiltration loads and Window gains are available but the *gians
> from Walls and Roof is missing. *Surely EnergyPlus does calculate
> all the above loads to size the Cooling Equipment but there is no
> such specific output.
> Regards
> Sandeep Kachhawa
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20110304/fbf14de1/attachment-0001.htm>
More information about the Bldg-sim
mailing list