Am working on a rather simple Chilled Water (CHW) Thermal Energy Storage (TES) System, but have run into an error where it does not appear that the kW is being shifted properly. Building in Las Vegas. Single Air-cooled Chiller using Chilled Water Storage to off-set demand charges. Testing the model with and without the TES, shows that the kW and costs are reduced, though maybe not as much as anticipated.

Digging into the model, the hourly reported kW from EM1-Cooling end-use and the Chiller kW consumption do not align. There is a single chiller; only cooling equipment in the model. Comparing the two with a HeatMap in the attached excel file shows that the EM1 does not drop off at all when the TES begins to discharge - but that the Chiller demand kW does. The Chiller kW is as expected; EM1 is not. In fact, EM1 with TES is only slightly less than EM1 without TES. Billing appears to be pegged to the EM1, thus, the cost reduction is not as much as expected. What is odd is that the annual sum of kW's and the daily SUMsubtotals between the EM1 and Chiller kW do align - what?! It is as if EM1 is not representing the kW shift that the Chiller is showing.

The CHW system does appear to charge, discharge, and track to the building load; so that is performing as expected.

The Utility rates are the same input and appear to be same on the output size. Equipment Controls and Load Management are different, b/c the non-TES doesnt have TES to charge/discharge.

So - why is the hourly kW from EM1-Cooling end-use different than the reported hourly kW from the chiller? Have scoured the DOE2 reference books and the Detail Report guide to no avail.

Thanks,
DARIC ADAIR PE, CEM, BEMP
Mechanical Engineer, Energy Analyst

HENDERSON ENGINEERS
daric.adair at hendersonengineers.com

LICENSED IN KS

HENDERSON PROUD SINCE 1970 | JUST GETTING STARTED.

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