mikesweeney's profile - activity

In my experience DesignBuilder's runtime is very close to EP Launch. -Have you tried exporting the IDF from DesignBuil

Is there any easy way to correlate a system node with the loop to which it belongs?

For example, I'd like to enter "AHU-1 Supply Side Inlet Node" and return "AirLoopHVAC" and "AHU-1 Loop" or something similar.

I've tried Walk_HVAC in Eppy and a few other Eppy functions, as well as looking through the SQL file, but can't seem to get it to find an elegant solution.

Update: I figured out a solution to this in Python using Eppy. It's a little bit hacky in that it relies on a lot of hea

System Node Loop correlation Is there any easy way to correlate a system node with the loop to which it belongs? For e

DOE-2 Command Line Hourly Reports I'm implementing a process using DOE-2 files which are initially built within eQuest a

Sketchup/eQuest polygon coordinate exchange I have a number of very old eQuest models (5+ yrs) that need to be updated f

From the Input-Output Reference: "The window vertices that you specify in the FenestrationSurface:Detailed object are t

i'm not sure about cooling in the floor, but designbuilder 5.2 has a "radiant surface" component you could try. or look

PTACs don't typically specifically have humidity controls, but if you lower the supply air coming off the PTAC it may re

does the floor cooling system have chilled water? if so, you'd need to have a chilled water plant connected to it. if yo

understood. good question and i'm not sure i have the answer; i'd reach out to the DesignBuilder team directly or look t

There should be a sub-folder within the DesignBuilder schedules library called "ASHRAE 90.1-2007." Most of these profile

it sounds like you have a heating setpoint of 20, but either no cooling setpoint or no cooling equipment assigned to you

This has been addressed in detail here: There's just too much going on in the SS-D reports to accurately pull out venti

This has been addressed in detail here: There's just too much going on in the SS-D reports to accurately pull out venti

On second thought, I think the answer is much more complicated than my initial response. I'm editing my first answer now

If you just need the peak values then the "SS-D Building HVAC Load Summary Report" should give you building + outdoor ai

The "SS-D Building HVAC Load Summary Report" should give you building + outdoor air. There will be some other HVAC-relat

I'm experiencing the same issue with a LEED Baseline building model. I have about (5) VAV units, each with roughly 20 zones and as might be imagined, manually entering the requirements for each zone's terminal unit/DesignSpecification:OutdoorAir will be very cumbersome. Has this issue been sufficiently addressed so that there is a way to simply specify the total outdoor air required at each baseline system level?

Coefficients 1 thru 4 for your Pump:VariableSpeed objects are 0, 1, 0, 0, respectively. This may be your issue. I don't know if there is a repository for variable speed pump curves available anywhere, but I'd try running it with a coefficient of 0, 0.5, 0.5, 0, respectively. This ought to approximate the electric output of a variable speed pump well-enough to know if this is the reason for your energy consumption issue.

Edit: In addition, at least with this configuration of your chilled water loop you may need to change the "Chiller Flow Mode" on your chiller to "LeavingSetpointModulated" in order to allow the flow to vary through the chiller.

I seem to have circumvented the problem with an EMS script which uses a Temperature Setpoint actuator at the node immediately following the pre-cooling coil and simply hard-sets it to a constant 12.7C.

I'm pretty new to EMS so please feel free to comment if you think there is a better or more elegant way to accomplish this within DB.

EnergyManagementSystem:Actuator,
   PreCoolCoilSAT,
   CLG COIL AIR OUTLET NODE,
   System Node Setpoint,
   Temperature Setpoint;

EnergyManagementSystem:ProgramCallingManager,
   ScheduleAvail Manager,
   InsideHVACSystemIterationLoop,
    PreCoolCoilSATPrgm;

EnergyManagementSystem:Program,
    PreCoolCoilSATPrgm,
set PreCoolCoilSAT = 12.7;

Your guess is correct, and thanks for the response. It does seem like the setpoint being overridden by a SetpointManager:MixedAir and unfortunately you're correct that it seems to mainly be a function of the way that DB translates its gui inputs into idf objects. I've noticed this for a few other esoteric hvac inputs as well.

In any event, I'm also providing an answer to the original question which shows some very simple EMS code that seems to work.

I'm modeling a low-temperature operating room being served by a constant volume air handler (it's really only constant volume due to hospital ACH requirements). The model is entirely within DesignBuilder v5.0.1

The air handler's SAT setpoint is 43F and in the design there are two chilled water coils in the mixed air stream that are controlled separately and in series to meet this temperature. The first coil is served by a campus chilled water loop and brings the air down to 54F. The second is served by a low-temperature air-cooled chiller which brings the SAT down to the required 43F (after accounting for draw-thru fan heat). The energy purpose for this arrangement is to use the high-efficiency campus plant for as much as possible, and to then only load the relatively poor-performing air-cooled chiller with the remainder but to also avoid excessive unloading on the air-cooled chiller.

I've tried a number of setpoint manager configurations for this arrangement and the closest I've gotten is to place a 54F setpoint manager after the first cooling coil, a 43F setpoint manager after the second cooling coil, and a 43F setpoint manager after the supply fan. This correctly forces the low-temperature chilled water coil to supply 43F air but the campus CHW coil seems to disregard the 54F setpoint manager and just get the air as close to 43F as it possibly can, which results in temperatures substantially lower than 54F when the mixed air temperature is below the coil's design entering air temperature. In turn, this leads to poor part-load performance and excessive unloading at the air-cooled chiller.

I've also considered using a pre-cooling coil but it looks like this only pre-cools the outdoor air and not the mixed air stream. This is an option but it would be difficult to control the amount of cooling of the outdoor air that would be required in order to bring the mixed air temperature to the 54F setpoint due to variations in the return air temperature at different points in the day. One idea for this approach might be to write an EMS script changing the pre-cooling setpoint to some function of the delta T between mixed air temperature and outdoor air temperature.

Does anyone have any experience with a similar issue? Curious to know if this can be solved with a different setpoint manager/coil configuration, or if I'll need to leave the Designbuilder interface and/or utilize EMS code.

I'm modeling a medium-size hospital facility in Philadelphia, PA, using DesignBuilder v4.7, and when I change the lighting on certain zones from 1.2 w/sf to 0.8 w/sf, the district cooling for the entire facility drops to zero and unmet cooling hours increases for nearly all zones to 100%.

When comparing IDF files, the only difference is that for any of the problematic zones, "Design lighting Level (W)" is changed. The cooling difference is stark: Changing a single 400-sf conference room from 1.2 w/sf to 0.8 w/sf while leaving the remaining 200,000 sf unchanged at 1.2 w/sf will cause the entire district facility consumption to drop from a reasonable (113,730) kBtu to (0) kBtu over a 24-hour weekday in August. This pattern holds true across the year regardless of simulation time.

I've tried pulling out the District Cooling on the air handlers and replacing with DX units, as well as replacing the District Cooling with a default Air-Cooled Chiller, but in all cases the cooling remains at zero. As far as I can tell, error logs don't seem to show anything relevant. I'd upload IDF/ERR files, but I don't have enough karma.

I’ve also tried transitioning from E+8.3 to E+8.4 to no avail, and I’ve searched through Unmet Hours as well as the general E+ ChangeLog but I haven't found anything that clues me in to what might be causing this issue. Is this a known issue? Any suggestion is greatly appreciated. Thanks!