Hello,
I am modeling an existing building with multizone air handlers with chilled
water coils for cooling and hot water coils for heating. The hot water is
generated by a gas furnace. I am seeing some discrepancies in my gas usage
from actual to the simulation. In the actual building, the gas usage is
only high in the winter months (the building is in the south) and is next
to nothing in summer months. I have tried all the various methods of coil
control under the "heating" tab and cannot get the simulation to reflect the
real life usage. Does anybody have any ideas on how to control the heating
better? Representative files are attached.
Marcus Eliason
I'm happy to look at your inp file, but I can't open it with eQuest. My
initial guess is that you have a pilot on all summer, or that your boiler is
cycling at an inefficient part load ratio in response to small demands.
--
Karen
Yes, where is your weather file?
My guess is, your chilled air stream needs to be mixed with heated air to raise it to a proper zone temperature.
Matt Daly
I looked at your .inp file - with a multizone system, you have the
heating coil of the dual duct scenario running all the time - it doesn't
look like you can set the minimum flow rate thru this coil to 0, which
means theoretically there is always a heating load, and perhaps the
boiler is running constantly during FAN ON conditions. Just a guess.
Also, you have the heating and cooling setpoints at the same temp (68
degrees). From my experience, you don't want to do this...it may cause
unexpected problems, especially when you are talking about multiple
thermostats controlling a complicated dual duct system.
James Hansen, PE, LEED AP