Is there a way I can create a schedule to lockout either the heating or
cooling system based on the time of year? I am modeling a residential
system, so I don't want it to try and satisfy heating a cooling loads
simultaneously in different zones. Thanks
--
Cory Duggin, EI
Cory, your query needs more description to include what you're trying to
model and what you've input, but if you've got simultaneous calls for
heating and cooling being handled, it sounds like you have either a
multi-zone system or multiple systems specified where you want only (1)
single-zone system.
If I were trying to model the behavior of the HVAC in my apartment
accurately (a simple CV electric furnace with DX cooling controlled by a
single remote thermostat), I'd group all conditioned spaces and their
zones under a single system, taking care to assign the thermostat zone
where the thermostat actually resides - it's the zone highlighted red in
the graphic under the airside HVAC tab.
I'd suggest revisiting the quantity and type of system you've specified
first, and modify/reassign your systems/zones as necessary to see if
that's where the problem resides. If you're still having troubles,
you'll need to provide a better description of what sort of system
you're trying to model (layman's terms are fine in this forum) and what
you've tried to specify on the model side. Attaching your project's
.inp/.pd2 files may encourage others to help troubleshoot also ;).
Best of luck!
~Nick
NICK CATON, E.I.T.
Whoah buddy =)!
First, let me give the preface that I'll be passing the 70hr mark for
this workweek tonight, so I'm kind of in zombie-mode right now XD!
Okay, I reckon you're hunting rabbits with a bazooka by resorting to an
absorption chiller/boiler setup to approximate your gas furnace! I'd go
ahead and save your work in a separate file for reference, then I'd step
back to the wizards to try a packaged single-zone furnace with DX
cooling for your 2-story zone, and a single-zone heatpump (DX/DX) for
your garage. Make the systems "on" 24hrs with intermittent fan
operation, and be sure you're not specifying "system per zone." Use the
shell wizard to be sure the zones are assigned to the right system.
If you wish, you can restrict heating and cooling availability for each
system, the way a residential thermostat has "heating" and "cooling"
modes, with a COOLING-SCHEDULE and HEATING-SCHEDULE. By default,
heating and cooling are generally available whenever they're called for,
but you can edit that without going to a chiller/boiler system ;).
If you are finding your building is flip-flopping between heating and
cooling hour-to-hour in the dead of summer, it might be a sign other
items are off... check your envelope constructions/layers, and note that
oversimplifying geometries/spaces (i.e. - one per floor) may result in a
lot of thermal mass from partitions being excluded that would otherwise
be a stabilizing presence.
I'm copying the eQuest list, because I will be of little use to you
others in the next 24 hours... Our strength is in numbers, so do keep
everyone in the loop as you work through this and you'll get the best
chance of quality assistance - best of luck =)!
Back to the grindstone...
~Nick
NICK CATON, E.I.T.
Based on what you have said, I think I just need a new heating and cooling
schedule. I found them in my component tree, but I am not sure how to do
what I want because the annual schedule only specifies an ending month and
day. How do I know when that schedule starts?
Cory-
For annual schedules, they automatically start at the beginning of the year. If you need it to start at a certain time of the year, you'll first have to create one that ends just before your needed start date. Then you can designate when you want your schedule to end. I'm not sure how much sense that made, but I hope it helps!
Adam Towell
Cory, I would recommend a test run, detaching all schedules, just to let the
auto-size engine do its work; you should see comparable loads. I find
uncoordinated schedules can cause all kinds of ruckus.
Create a second "week schedule" for cooling and heating modes, just right click on Weekly Schedules and click create new weekly schedule. Then when the dialogue box opens under "Creation Option" click create from cope and copy the existing cooling or heating weekly schedule. Then go into the new weekly schedule and set all days to a day that has a high set-point for cooling (and one with low set-points for heating). If there are no days like that you will need to create a new day schedule. If you create a new day schedule you can set the heating set point really low and the cooling set point really high and then assign this for every day of the week in the new weekly schedule. Then assign the new weekly schedule to teh season that you want to "turn off" cooling or heating. SO if you created a heating schedule to prohibit heating in the summer you could assign this to month "8" and day "31" and assign the existing schedule to all days before and all days after.
Good Luck!
Joe Fleming
E.I., LEED AP BD+C, BEMP
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