Chiller cooling capacity sizing

asked 2022-09-24 19:45:04 -0600

obuchely's avatar

updated 2022-09-26 09:39:33 -0600

I am sizing a chiller for a project. I did the model using openstudio. I ran the simulation and check the openstudio report in the Plan loops details section. The auto sized chiller cooling capacity is 1,561 Tons which is too high for the building.

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I plotted the chiller evaporator cooling rate for the cooling design day and the maximum value is 1,700 kW (485 Tons) witch is a lot lower than the 1,561 tons.

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Then I open in E+ the IDF file generated in openstudio. I added the ComponentSizingSummary, HVACSizingSummary, FacilityComponentLoadSummary, CoilSizingDetails and ZoneComponentLoadSummary report in the Output:Table:SummaryReport in E+ (by the way I don’t know how to do it in Openstudio. Any help will be appreciated ) Checking the energy plus reports I found:

The 1,561 (5,489,709.35 W) Tons in the OS report are named as: Initial Design Size Reference Capacity. I don’t understand what the meaning of this value is.

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In the Report: Facility Component Load Summary the grand total is 207,9 kW (59.4 Tons) which is a too low for the total building load.

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Then in the next report: Cooling Peak Conditions the Peak Sensible Load with Sizing Factor is 877869.96 [W] (250 Tons).

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I am not sure which value is the correct one for sizing the chiller and I don’t know why there are too different. Is there any other report that I should have checked?

Any help will be appreciated.

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