OpenStudio v1.13.0: HVAC, Output Files, Split Systems & Ex.
UC Irvine students working on energy modeling. At present, I am attempting to model a commercial community building; see Google link below with associated errors. I have also included a screenshot of the HVAC tab (which includes an older gas fired Carrier AHU, ducted with no VAVs, and R-22 refrigerant).
1) HVAC System - We have a functional rooftop unit, Zone 1 & 2 are controlled, Zone 3 is not controlled. I am unsure as to what all the individual entries on the right-hand tab are for, and what values I should put for them, regarding the "Packaged Rooftop Air Conditioner" (see screenshot). I am also getting a warning about near freezing temperatures in the system (see associated error report for more errors as well). Is this a sizing issue?
* Warning * CalcDoe2DXCoil: Coil:Cooling:DX:SingleSpeed "COIL COOLING DX SINGLE SPEED 2" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = -3.52 C. * ~~~ * ...Occurrence info = RUN PERIOD 1, 01/01 06:02 - 06:03 * ~~~ * ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil * ~~~ * 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 17.864 C. * ~~~ * 2) may have a low air flow rate per watt of cooling capacity. Check inputs. * ~~~ * 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs.
2) Output Files of Interest - Need to better understand Simulation tab output reports including how to read “epluout.err” and “eplustbl.htm”; should I be reviewing others reports of importance aside from the aforementioned?
3) Split Systems - I am looking to model replacing the old AHU with some split (ductless) systems to make room on the roof for solar panels. Any recommendations on how to model this HVAC equipment and compare results of the retrofit?
4) Working Open Studio Model - Does anyone have full, running OpenStudio models or examples that I can use as a reference?
Welcome to unmet hours. The way this site works requires you to post one question only per post, so you can draw appropriate and complete answers.
2) Have you read the E+ documentation, especially Output Details and Exampes, section "Output File List"?
3) This "AHU" being on the roof (thus I'd call it a Rooftop Unit (RTU)), it likely provides fresh air. How will you deliver this fresh air using your new ductless system?
4) There's a measure called "Create DOE prototype building", search for it.
1) Please do a search. Try "DX coil freeze" or "CalcDoe2DXCoil" as a search term