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Solar Collector and CHP Coefficients

asked 2020-01-29 13:20:05 -0500

roham's avatar

updated 2020-01-29 17:21:19 -0500

I am working on my master thesis with energy plus. During my simulation I have used solar collectors and CHP systems, in both cases I have used the templates in the example files SolarCollectorFlatPlateWater.idf and MicroCogeneration.idf in the results of my simulation in SYSTEM NODE TEMPERATURE the Inlet temperature of these component are Higher than Outlet Temperatures Which is also the case in the example files which makes no sense so I am guessing there are some problems with the Coefficients in the Performance Object associated with these objects. If it is, may I have the correct Values?


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Please provide more information, like proof of what you're saying: take one of these two example files, tell us exactly what variable you're looking at, and include a graph that'll show that the inlet temp is higher than the outlet temp. This will save us the time of having to investigate in the dark and will maximize the chances of actually getting help! Thanks.

Julien Marrec's avatar Julien Marrec  ( 2020-01-29 16:52:32 -0500 )edit

I have added the chart I can also send you the file by email if you want

roham's avatar roham  ( 2020-01-29 17:04:18 -0500 )edit

Thanks for the graph @roham. I'll have to look into it tomorrow (past midnight here). It does seem very weird at first glance indeed, and I'm having a hard time tracking the node connections (MICROCHP SENERTECH Pump-MicroCoGen1NodeviaConnector versus MICROCHP SENERTECH Pump-MicroCoGen1Node). If you have already drawn the loop with all nodes labeled, it'd be helpful to share it.

Julien Marrec's avatar Julien Marrec  ( 2020-01-29 17:12:55 -0500 )edit

Thank you so much I really appreciate

roham's avatar roham  ( 2020-01-29 18:09:17 -0500 )edit

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answered 2020-01-30 04:52:07 -0500

updated 2020-01-30 05:07:07 -0500

I switched the reporting frequency to detailed and modified all Output:Variable to be this:

! Using regular expressions to match anything that starts with "MICROCHP" and ends with "NODE"
Output:Variable,MICROCHP.*NODE,System Node Temperature,detailed;
Output:Variable,MICROCHP.*NODE,System Node Mass Flow Rate,detailed;

Output:Variable,*,Generator Coolant Inlet Temperature,detailed;
Output:Variable,*,Generator Coolant Outlet Temperature,detailed;
Output:Variable,*,Generator Engine Temperature,detailed;
Output:Variable,*,Generator Produced Electric Power,detailed;
Output:Variable,SMALL SOFC HEAT REC INLET NODE,System Node Temperature,detailed;
Output:Variable,SMALL SOFC HEAT REC INLET NODE,System Node Mass Flow Rate,detailed;
Output:Variable,*,Water Heater Final Tank Temperature,detailed;
Output:Variable,*,Water Heater Heating Rate,detailed;

Now here's a graph showing the importance of whether that cogen is actually running, this is for January design day for a subset of the hours (between 8:00 and 12:00). The shaded areas are where ('MICROCHP SENERTECH PUMP-MICROCOGEN1NODE', 'System Node Mass Flow Rate', 'kg/s') is strictly > 0

Click on it to enlarge:

image description

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Thank you so much you really helped me a lot

roham's avatar roham  ( 2020-01-30 16:58:09 -0500 )edit

If that solves your problem please mark the answer as accepted by clicking on the check mark below the Upvote/downvote buttons so the thread is marked as resolved.

Julien Marrec's avatar Julien Marrec  ( 2020-02-03 04:09:36 -0500 )edit

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Asked: 2020-01-29 13:20:05 -0500

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Last updated: Jan 30 '20