[Equest-users] Lighting densities and Electrical equipment contributing to Space Heating

[Taylor Sharpe]

Hi everyone,

I feel that this topic must have been discussed at some point, but an
exhaustive archive search got me nowhere, so I thought I'd throw together a
post of my own, especially since I'm working on an eQuest model of a small
server building which is heated in part by a large number of computers that
run many hours every day.

I'm interested in how eQuest treats electric loads - from lights, computers,
refrigerators, etc - as regards space heating.  I had always assumed that,
especially in the case of lights, much of the energy used would be converted
to heat within the building, and contribute to space heating.

However, I set up an experiment to test this and found that the results were
far different from what I'd expected: I upped the lighting density in an
existing natural-gas-heated building model by about 15x and compared the
electric use from before and after the lights were increased.  I converted
all values to mmBtus for easy comparison.  To my surprise, I found that only
a very small fraction (about 6%) of the mmBtus added to the building through
those lights contributed to space heat.  The kWh recorded were increased
hugely, but the heating energy required to keep the building heated was
almost the same in both cases.

I repeated the experiment, upping misc. equipment instead of lighting, and
saw a similar result.

Does anyone have any knowledge of what equations eQuest uses to decide how
much electrical energy use is converted to heat and added to the space in
which it is installed?

Regards,
Taylor Sharpe
Sharpe Energy Solutions
newspectrum at gmail.com
(541-840-5698)
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