RyanStochastic's profile - activity

I'm not aware of any optimization for TES in E+; a quick search of the documentation for the text 'optimiz' or 'optimis' might get you what you need.

As for controlling based on the peak pricing, you will likely have to import the pricing signal as a schedule, and use the energy management system language to roll your own algorithm/logic for controlling the TES.

To your last question, you can output the hourly (8760) results from your simulation (they should come out automatically from the DOE models), then use your favorite analysis software (Excel works in a pinch) to pull out the records for the peak/off peak hours separately and sum/average them as you see fit.

DView may have the ability to filter by hour of day or day of year - i'm not sure.

Good luck!

Hi Jason, thanks for your answer! It's definitely helpful, and your lists of objects are exactly what i need to get started. One thing I'm still not clear on though are the controls - could you comment on VAV controls in energyplus? Of the 31 objects you've listed there, which ones actually govern how much airflow goes to each zone, or through each system?

Hi Julien, I take no offense to your question - and no, I'm not a VAV system expert in the real world. However, even if I had expert knowledge of real-world HVAC systems, the modeling and simulation methods of energyplus are tough to sort out from the documentation, in my opinion, and I figured that i wouldn't be the only one with this question - so i asked. In Jason't answer below, there are 31 different objects required for a VAV system (and he didn't include individual Node objects). Figuring out that list is one challenge; learning how they all interact and connect is another.

Greetings,

I am aware of the energyplus example files, the input/output reference, and engineering reference, and i have spent a while with all of the above.

I'm still not able to figure out what is required to model an HVAC system in energyplus, or how to properly model VAV controls so that the volume of airflow changes to meet the load in each zone. There are terminal HVAC objects, fans, airloop objects, supply loops, demand loops, branches, branchlists, controllers, nodes, schedules, and plenty more. How do they all fit together?

Can someone explain in a concise response, what energyplus objects are required for a VAV system, and what the role of each object is? I've read the documentation on most all of the objects in the VAV system example files, but there are just too many, and I can't keep it straight. Perhaps a comprehensive, brief summary exists somewhere that I haven't looked?

Bummer. Thanks for the confirmation!

Does energyplus have an output option for total energy consumption by zone and fuel source?

In the Output:Table:SummaryReports portion of the documentation, there is a table called ABUPS, or Annual Building Utility Performance Summary, and within ABUPS there is a table called 'End Uses' that summarizes the total annual building energy consumption by end-use (heating/cooling/lighting/etc) and fuel source (electric/gas/etc)- I'm looking for a similar table that corresponds to a single zone, instead of the entire building. Alternatively, a table that listed total annual building energy consumption by zone and fuel source would suffice.

Does such an output table exist? If not, is there an easy way to generate one? Or is there any output variable that shows total energy consumption (of a given fuel type, e.g. total electric or total gas) per zone?

Cheers

@MattSteen, thanks for the suggestions. I've edited the question accordingly. It's both an input and output question, i'm interested in HOW to simulate the system with and without a VFD, and the results of the simulations for each case.

Assume I have a working E+ building model with a constant-speed fan or pump. What's the best way to model the addition of a VFD to this building model? Do I just need to change the fan or pump object to variable speed? Or is there more to it than that? I'm interested in seeing the energy savings from adding a VFD.

What controllers might need to be changed? How is the process different for fans and pumps?

Thanks in advance!

re: 'some other things too'. and 'the rub'... If someone can provide a more comprehensive list of things that make the difference between EnergyPlus and Equest, I'll nominate that as the answer. The answers thus far do provide good insight into the question, and they are much appreciated. I'm hoping to get to a more definite/complete/final list of reasons or areas where one engine outperforms the other. I.e. for novel systems, must use energyplus, for a basic building, equest will do fine.

@Krishnan, re: "(too many to list here)" - that sort of list, a list of the can's can'ts, and pro's con's of the two platforms would make a great answer to this question.

I know that EnergyPlus models some things in more detail than eQuest, and that eQuest runs much faster than EnergyPlus. What are the best applications for each platform? Why use EnergyPlus if I can get a much faster result with eQuest?