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Hi!
OK, as you can see from the replies it's quite a
messy jungle with PCs nowadays. I've also been a few times in the position of
trying to justify the needs/benefits of a new work-station for simulations (not
only TRNSYS) and it's not always easy. Your interest in reducing sim time is
understandable as with your current setting you end up easily in >24hr
simulation times (thousands of 100sec sims).
Trying to summarize some guide-lines from
previous mails:
* If you have an older generation CPU, then
upgrading to a good PC of the current CPU generation will probably already
halve your simulation time, give or take. This you can see e.g. from Rafs test,
or comparing bench-mark results on net reviews.
* If you already have a PC with a current
generation CPU, then you have to start thinking about price vs. performance.
Getting a 20-30% CPU performance boost (sim time reduction) compared to
good standard PCs might almost double the price of your new work-station,
this might be difficult to justify.
* Also, looking at the previous point: If you can
divide your problem into two, buying e.g. two good standard PCs instead one of
the fastest possible, might almost halve your total sim time instead of the
20-30% reduction for one simulation for the same price. And after the project
you have two perfectly good PCs to give to new employees, instead of
one.
* The benefit of a dual-core CPU is harder to
comment on. You might be able to do with one PC the same as with two computers
as described above, but it would be better to test it before buying. This is
possible at least with TRNSYS-only, but it might be more complicated in
combination with other programs. You should be able to test this with a single
core CPU, on your current PC (the simulation will be a crawl, but at least
you should be able to see if it works).
* Running two simultaneous simulations on dual-core
generates a lot of heat, take care that the cooling of the PC is well done. If
you are running simulations of several hours like this, you might end up
crashing your hard disk in no-time because of the elevated operating
temperature. This problem is not over-exaggerated!!!
* With a dual core CPU you can work normally while
a TRNSYS simulation is running in the background at full speed. This wasn't
possible with single core CPUs.
* RAM isn't an issue with TRNSYS, anything above
1GB is overkill, unless you are using other software which need more (actually,
already 1GB is overkill, if only for TRNSYS+OS).
* Hard disk isn't an issue either, modern HD:s can
handle about any amount of data that TRNSYS itself has to read and can spit out.
(Unless you are doing something else that's HD intensive at the same
time)
A suggestion to TRNSYS development
group:
It might be a good idea to have some general
guide-lines about this on the TRNSYS home pages in addition to the general
hardware requirements/recommendations. Generally, when a new project involving
simulations is started, almost always the need for a new computer
is discussed in the first meeting. The "Hardware requirements" section
in the manual does not give much help considering e.g. Rémis problem. This might
easily lead to "buying overkill" or spending money on the wrong part of the
hardware. And trying to google the www you end up spendings various hours
reading and still not knowing which way you should go.
Regards
Janne
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Janne Paavilainen MSc, PhD student Researcher in Energy and Environmental engineering ----------------------------------------------------------------------------- Solar Energy Research Center SERC Dalarna University College SE-781 88 Borlänge Sweden ----------------------------------------------------------------------------- tel +46 (0)23 778728 fax +46 (0)23 778701 e-mail: jip@du.se ----------------------------------------------------------------------------- www.du.se www.serc.se www.eses.org www.uni-kassel.de/fb15/ite/solar/solnet/ -----------------------------------------------------------------------------
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