kwalkerman's profile - activity

Looks like you are using EnergyPlus. For AirLoop:HVAC, you must have a SetpointManager on the supply outlet node. You

There is also an EnergyPlus Object DaylightingDevice:Tubular which you may be able to use for this purpose. This object

change the temperature schedule referenced by the ThermostatSetpoint object.

The CSV files will output whatever information you request using Output:Variable. What Output:Variables have you reques

try turning them to "off" & see if that fixes the problem, then you can drill down on which one is causing the issue

what weather file indicators do you have checked as "yes" under RunControl? Sounds like this issue: https://github.com

Below the min PLR it will ride the part-load fraction correlation curve (kind of confusing because part load fraction an

if MinPLR = 1, then you're relying on the VRF cycling & can use old curves without going back and re-calculating the

if MinPLR = 1, then you're relying on the VRF cycling & can use old curves without going back and re-calculating the

@rraustad - I just independently discovered this & a temporary work-around is to set the minimum PLR equal to 1.0.

@rraustad - I just independently discovered this & a temporary work-around is to set the minimum PLR equal to 1.0.

Are there any examples of using regular expressions for filtering output variables?

Transition Guidelines for GroundHeatExchanger from EP Version 8.8 to 8.9 In EnergyPlus 8.9, the file "Rules8-8-0-to-8-9-

Coil:UserDefined uses EMS in order to run. I agree that there are many other areas where incorrect coefficients could re

Thanks for this answer. I looked in ASHRAE 90.1 and LEED for a definition and couldn't find one for either. My thinkin

Exceptional Calculation Method Official Definition? Is there an official definition of an "Exceptional Calculation Metho

I found a solution that provides the following on the supply side of AirLoopHVAC: hot gas reheat for dehumidification

Thank you. Does Coil:Cooling:DX:TwoStageWithHumidityControlMode allow variable airflow? Many of the DX coil models str

AirLoopHVAC:UnitarySystem - Additional Heating Coil I am using AirLoopHVAC:UnitarySystem to model an air-source heat pum

I am modeling a refrigerated storage facility that uses a chiller to cool a brine loop, and then has brine hyrdronic coils in each cooler to provide cooling.

In EnergyPlus, the refrigeration systems all use refrigerant as the heat transfer fluid. I am not able to use the usual chiller and hydronic cooling coils (Chiller:Electric:EIR and Coil:Cooling:Water) as the Coil:Cooling:Water is limited to a design water inlet temperature above 0 C. There may be other limitations in Chiller:Electric:EIR that I have not yet uncovered.

Is there a way to model my system as-is, or I am stuck with using the refrigeration system components and accounting for pumping energy separately?

Thank you.

Brine Cooling System in EnergyPlus I am modeling a refrigerated storage facility that uses a chiller to cool a brine loo

Is there a way to check that the faces are being exported properly & that they are oriented correctly? If the faces

Is there a way to check that the faces are being exported properly & that they are oriented correctly? If the faces

have you checked the flowrate at each node? Sometimes when there is zero flow, the temperatures don't align.

I see that you have resolved the plant Loop Temperatures by setting your pump flow to "intermittent". In regards to the

It sounds like you are trying to accomplish something similar to return air integrated into lighting systems. In those s

In some instances, ZoneHVAC:UnitVentilator can do what you need in one ZoneHVAC unit. It allows more control of outdoor

@Gio - yes. You might want to look at the WaterHeater:HeatPump objects.

.. continued from above If you look at the node connections between the two objects, I think it'll make more sense. Wi

AirTerminal:SingleDuct:Mixer is a special type of air terminal that allows you to provide air to a ZoneHVAC:Equipment ob

From the EnergyPlus Documentation: So the Outdoor Air Flow Rate fields for the VRF unit will be set to 0.

Looks like you might be able to achieve what you want with multiple chillers by using the CentralHeatPumpSystem object

you're welcome!

look at your electrical end-uses on a timestep basis, particularly the refrigeration equipment. What refrigeration equipment setup are you using? I have had issues mixing ZoneHVAC:RefrigerationChillerSet with the simplified system available in Refrigeration:CompressorRack. This was EPlus version 8.4. I have not had the chance to create an error report for it yet.

Also, I've experienced negative electricity use in the past with the water to air heat pump model if my refrigeration curve coefficients were not set up properly. I suspect that you have a refrigeration curve in the wrong place, or one of your coefficients is not correct.

DesignBuilder uses EnergyPlus as a simulation engine. In EnergyPlus the ZoneHVAC:Baseboard:RadiantConvective object allows you to assign surfaces which are absorbers of the object's radiant heat.

See: ZoneHVAC:Baseboard:RadiantConvective documentation for the field set: Surface Name, Fraction of Radiant Energy to Surface

@Eric Wilson - I do not usually use those curves with Fan:OnOff - if you are getting 0 fan energy use with those curves and VRF, sounds like an issue you need to report to the development team.

@Eric Wilson - I have used Fan:OnOff sucessfully with both ZoneHVAC:PackagedTerminalHeatPump and ZoneHVAC:TerminalUnit:VariableRefrigerantFlow. When you say that Fan:OnOff doesn't show any energy use due to curves - what curves are you referring to?

great! Thanks Jason!

There is no way to do this directly in Energy+ without writing a script using EMS (Energy Management System). The easiest way I have found to coordinate schedules is to use excel to create the schedules. In excel, I can coordinate values and use conditional formatting to determine values for each schedule. I then use excel's "concat" function to develop Schedule:Compact objects. The image below shows schedule development for occupancy, lighting/receptacle and HVAC systems. The same could be done with thermostat schedules.

The short answer is that I believe that having a SurfaceProperty:SolarIncidentInside object inside a zone triggers EnergyPlus to turn off it's internal calculation for solar gain on surfaces.

The long answer (and why I believe what I stated above):

I ran a quick test on the example file for this object. The example file is "CmplxGlz_SchedSurfGains.idf"

For the test, I deleted the SurfaceProperty:SolarIncidentInside object for surface "ROOM102 FLOOR". If you look at the output file "CmplxGlz_SchedSurfGains_delete_surface.csv" - "ROOM102 FLOOR" reports 0 for all hours for Surface Inside Face Absorbed Shortwave Radiation.

I then further modified the file to delete all SurfaceProperty:SolarIncidentInside and ComplexFenestrationProperty:SolarAbsorbedLayers objects. Running this file resulted in Surface Inside Face Absorbed Shortwave Radiation reported for all faces, except for "ROOM102 South Wall". I'm pretty sure that "ROOM102" South Wall is not reporting Surface Inside Face Absorbed Shortwave Radiation due to the zone geometry.

The files can be viewed by following this Dropbox Link.

The only way to model a refrigeration system properly is to use the Refrigeration objects. The normal zone conditioning equipment (even IdealLoads) does not work well for refrigerated zones.

For refrigerated zones, you will need to use the following equipment:

For the Zone: Refrigeration:AirChiller ZoneHVAC:RefrigerationChillerSet

For the refrigeration system, some combination of the following:

Refrigeration:Condenser:AirCooled

and/or

Refrigeration:Condenser:WaterCooled

and/or

Refrigeration:Condenser:Evaporative Cooled

and

Refrigeration:Compressor

Take a look at the example file: "RefrigeratedWarehouse.idf"

My understanding is that the <50% or >130% warning is because the HeatExchanger:AirToAir:SensibleAndLatent only provides inputs for heat exchanger effectiveness at 75% and 100% airflow. At higher and lower airflows, the effectiveness may vary significantly from that given. (wouldn't it be nice to have a curve, instead of a few inputs?) If your heat exchanger has a similar effectiveness at low and high airflows, this warning can be safely ignored.

The severe warning is more serious. Like high and low airflows, different types of heat exchangers will have different effectiveness with unbalanced airflows.

I would obtain the actual effectiveness of your heat exchanger at various airflow rates, and look at simulation detailed outputs:

Output:Variable,*,Heat Exchanger Sensible Effectiveness,hourly; !- HVAC Average Output:Variable,*,Heat Exchanger Latent Effectiveness,hourly; !- HVAC Average

I used to purchase my AMY files from Weather Analytics. They would build files for custom time periods, but I can't figure out if they are still selling these files. They list AMY files on their website, but I can't figure out where to purchase them. I sent them an email inquiring, over a month ago, but never got a response.

Is there anywhere else to get AMY files easily and at a reasonable price?

EDIT:

White Box provides full year historical data, but for many Measurement and Verification applications, it is useful to have some months out of the current year, or have a year's worth of data starting in the middle of one year and going into the middle of the next. I haven't been able to find anyone who does anything like this.