----- Original Message -----
Sent: Wednesday, January 02, 2002 6:35
PM
Subject: RE: [GBlist] Setback
Thermostats, basic question
The
greater the quantity of thermal mass in the building, the earlier you will
want to start the warm up process.
This may also affect how low (how much difference in temperature) you
set the thermostat back.
Ralph
Thanks for the reply. Another
question if I may, I must have missed this day in school, maybe it was
the 60's:
My assumption is that heating up a solid
thermal mass is more energy expensive than heating the surrounding air, and
that at some point in a 10hr. period, a lower (greater difference)
setback temperature at night would end up using more energy than a higher
setting (Could a setting of 40F use more than 50F?) I guess that's
a question about the rate of heat transfer from a thermal mass to surrounding
air--how much in 10hrs., and the substance of what you hinted at in the above
snip. Without going through an entire heating season
trial and error, any idea as to where that point might be? Would it be that, in a 14on/10off hour cycle, the thermal
mass is always at a lower temperature than the surrounding air? (Forced hot
air system).
Comfort level is not really an
issue-- the building is unoccupied during the daily setback period and
most occupants would not really notice any effect of the radiant heat
mentioned in your and another thread posts. No water pipes to be
concerned with either.
Several responders noted that they saved
no energy from setting back their nighttime temperatures (in
contradiction to your opener that it will almost always save
energy). Care to hazard a guess as to why?
Thanks
Steve
