ericmartinpe's profile - activity

I was just speaking from a design perspective. I think there'd only be a preheat coil before the mixing box for frost co

I was just speaking from a design perspective. I think you'd only put a preheat coil before the mixing box for frost con

I was just speaking from a design perspective. I don't think I've ever seen the preheat coil located before the mixing b

I would say the mixed air stream. I don't have a source to point to, but why not take advantage of RA mixing/preheating

Can you just report it as an output variable? Output:Variable,*,Water Heater NaturalGas Energy,hourly; !- HVAC Sum [J]

Parasitic loads can represent anything that consumes fuel when the heater is on, including pilot lights. The prototype m

Circulation pipe losses are accounted for as parasitic loads on the water heater, so it may have to do with recirculatio

Sounds like a good use case for using the Python API in library mode. You can write a python script that looks up the va

Your experiment provides more evidence that your model is not very accurate. However, it does not prove that the simulat

It's CBECC that's creating these REVERSED surfaces automatically, not E+. E+ allows you to "share" surfaces from adjace

Could it be that one is unmet hours while occupied and the other is total unmet hours? Just speculating. This sounds lik

The ground is a significant source of heat loss, which your model ignores. You've essentially modeled a completely air-t

That sounds right. So, answering your question, the Central Cooling Design Supply Air Temperature in Sizing:System is th

That sounds right. So, answering your question, the Central Cooling Design Supply Air Temperature in Sizing:System is th

The ground is a significant source of heat loss, which your model ignores. You've essentially modeled a completely air-t

The ground is a significant source of heat loss, which your model ignores. You've essentially modeled a completely air-t

Here's one clue: ** Warning ** GetHTSurfaceData: Surfaces with interface to Ground found but no "Ground Temperatures

I would think it's the temperature at the setpoint node(s) in whatever SetPointManager is specified for that system. It

Joe Huang is an expert with weather files. His company, White Box Technologies, mostly focuses on TMY weather files, but

If you post a link to your model it might be easier to diagnose the inaccuracies. Some items that come to mind based on

If you post a link to your model it might be easier to diagnose the inaccuracies. Some items that come to mind based on

If you post a link to your model it could be easier to diagnose the inaccuracies. Some items that come to mind based on

If you post a link to your model it could be easier to diagnose the inaccuracies. Some items that come to mind based on

If you post a link to your model it could be easier to diagnose the inaccuracies. Some items that come to mind based on

The Sizing:Parameters object multiplies the heating/cooling capacities by the heating/cooling sizing factors. Looks like

Yes, you'd set the coefficients for the following curves so that they yield a value of 1 regardless of PLF/Temp/Flow (in

I don't believe there is a way to explicitly model bifacial PV in EnergyPlus. Only solar radiation incident on the norm

please report this issue on github.

Only solar radiation incident on the normal side (pointing outward, the side the right-hand rule points to) of the surfa

Are you referring to a water-to-air (water-source) heat pump cooling coil? Yes, there are a few options: Coil:Cooling:Wa

Check out PNNL's Copper tool, which can generate EnergyPlus performance curves for packaged DX equipment (and chillers)

Check out PNNL's Copper tool, which can generate EnergyPlus performance curves for packaged DX equipment (and chillers)

What command are you using to execute the simulations? I ask because if you're not using the "-p" option to specify a pr

I don't believe there is a way to model bifacial PV in EnergyPlus.

If you create your PV surface on top of the roof, it should take into account the reflectivity of the roof. From the doc

This could be due to an issue with the input files (e.g. missing OutputControl:Files or Output:Table objects) or maybe t

Can you export the rotated IDFs from DB? I suggest you do that to see how DB is rotating the building.

I'd export the IDFs from DB and compare them with a text comparison tool (e.g. BeyondCompare). See what DB is doing to r

I would model an unconditioned zone for where the air compressor is located and use an OtherEquipment object to characte

Where is the hot air coming from? You said the air source will be outdoor air. Is it coming from outside, or is it comin

The EnergyRecoveryVentilatory object contains an air-to-air heat exchanger and can be used to pre-heat/cool incoming out

Simulating a model in a different location/climate is not as simple as selecting a different EPW. You also need to modif

@Anurag_G and @Keigo you can also use PNNL's Copper tool to calculate curve coefficients.

@Anurag_G and @ Keigo you can also use PNNL's Copper tool to calculate curve coefficients.

@Anurag_G you can also use PNNL's Copper tool to calculate curve coefficients.

What are the appropriate fan curve coefficients and Fan Power Minimum Flow Fraction for the Fan:VariableVolume objects in an ASHRAE 90.1 PRM baseline model (System 5)?

I ask because there are some discrepancies between the ASHRAE/IECC code language and the Commercial Prototype Building Models. As noted in a previous Unmet Hours post, the prototype models use coefficients representing "Good SP Reset VSD Fan", which differ from the coefficients from 90.1 App G Method 2. Is this because the prototypes assume zone-level DDC where a SP reset would be required?

Regarding the "Fan Power Minimum Flow Fraction" field, both ASHRAE 90.1-2013 (6.5.3.2.1) and IECC 2015 (C403.4.1.1) state: "Low or minimum speed shall not exceed 66% of full speed. At low or minimum speed, the fan system shall draw no more than 40% of the fan power at full fan speed." I interpret this as meaning the baseline "Fan Power Minimum Flow Fraction" should be 0.66. However, the prototype models use a fraction of 0.25. What is the appropriate Fan Power Minimum Flow Fraction for a PRM baseline?

Another unrelated discrepancy I found in the prototype models for System 5 (used in medium office). ASHRAE (G3.1.1-4 Baseline System Descriptions) lists hot water boiler heating, whereas the prototypes use gas furnace heating. Are the ASHRAE prototype models not intended to represent ASHRAE ECB baseline models?