Can EnergyPlus accurately model VRF systems?

asked 2015-08-19 18:16:29 -0600

Sherry
111 ●1

updated 2015-08-19 18:30:06 -0600

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

We did a study and compared different modeling tools.

We found EnergyPlus has the most lab and field test data demonstrating the accuracy of the module. It also is able to model Heat Recovery VRF systems and it is able to model multiple HVAC systems per thermal zone. Therefore, EnergyPlus is able to model all of the common VRF installations in commercial buildings.

We want to hear your comments.

References EPRI (forthcoming), PG&E Emerging Technology study of a variable refrigerant flow system installed at the PG&E service office in Auburn, CA. Hwang, Yunho, et al. "Field Performance Measurements of VRF System with Subcooling Heat Exchanger." Purdue E-pubs. University of Purdue, 2012. Web. Aug. 2014. http://docs.lib.purdue.edu/cgi/viewco... Raustad, Richard. Domitrovic, Ron, et al. “Technical Subtopic 2.1: Modeling Variable Refrigerant Flow Heat Pump and Heat Recovery Equipment in EnergyPlus” Sept. 2013. Web. Aug. 2014 http://fsec.ucf.edu/en/publications/p...

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answered 2015-08-20 04:38:15 -0600

Jim Dirkes
3554 ●27 ●16

When you say "accurately model", it sounds as though you're asking for real world validation. I don't have that. I have, however, recently compared single curve representations of VRF, such as are used by some modeling software, against the E+ "segmented" multi-curve approach. It sure looks like there are hundreds of hours in most climates (near the curve transition points) where the E+ approach matches manufacturer performance much better. In case it might be helpful, there's an upcoming webinar sponsored by DesignBuilder (which I'm helping to present) that will promote DB's capabilities for VRF but will also show some of the curve differences between E+ and single-curve approaches.