Control of Chiller with Thermal Energy Storage

asked 2019-03-07 11:26:17 -0500

mldichter's avatar

updated 2019-03-11 17:21:37 -0500

I was trying to figure out what all the controlling objects do in the example file IceStorage-Series-ChillerUpstream.idf and came upon some strange behavior.

A little background. The plant side of this loop has a pump, chiller, and ice tank. The demand side has a pump and ONE water coil. There is a common pipe between them.

On the night of 3/12 and 3/13, the water coil is not cooling, the ice tank has charge, the ice tank has no flow through the ice tank part, the pump on the demand side is off, the pump on the plant side is on, and the chiller is chilling.

Also, the inlet temperature of the chiller is 7.283012856 and the outlet temperature is 7.22 during its midnight cooling, so not very much cooling at all.

What is going on? All I can imagine is that the chiller is chilling the heat from the pump that's running as the only water coil on the demand side is not providing cooling. Here is a google drive link to the files. All I did to the original file was change the run period and the output variables.

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Post Script
There is similar behavior with the IceStorage-Series-ChillerDownstream.idf example file.

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Post Post Script
The IceStorage-Parallel.idf example file also does not behave correctly.

I think it does during the weekdays

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but other times the chiller is on all the time and not cooling anything or charging the ice tank.

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What's going on!?!?!

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