I change the constant speed pump into a variable speed pump, but the result in energy consumption is still constant

asked 2017-02-25 08:53:06 -0500

updated 2017-05-03 19:50:43 -0500

I have built a model with HVAC cooling. I changed the constant speed pump to a variable speed pump but having the same constant result of energy consumption. I've heard that to omit the bypass pipes in the system and do so, but the result is still the same. Any advice or ideas? Here is my idf file: https://drive.google.com/file/d/0B2xx...

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answered 2017-02-28 15:36:05 -0500

mikesweeney
493 ●3 ●7

updated 2017-02-28 15:49:14 -0500

Coefficients 1 thru 4 for your Pump:VariableSpeed objects are 0, 1, 0, 0, respectively. This may be your issue. I don't know if there is a repository for variable speed pump curves available anywhere, but I'd try running it with a coefficient of 0, 0.5, 0.5, 0, respectively. This ought to approximate the electric output of a variable speed pump well-enough to know if this is the reason for your energy consumption issue.

Edit: In addition, at least with this configuration of your chilled water loop you may need to change the "Chiller Flow Mode" on your chiller to "LeavingSetpointModulated" in order to allow the flow to vary through the chiller.

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A set of pump curve coefficients is listed here.

ericringold ( 2017-02-28 15:39:34 -0500 )edit

Thank you very much! @mikesweeney Its the chiller flow mode setting that solve it! But the still the Condensing water pump is constant flow, I can't find any setting that related to this, would you know why?

paulthebro ( 2017-02-28 23:12:55 -0500 )edit

@Eric Ringold Thank you for providing this useful list!!

paulthebro ( 2017-02-28 23:16:16 -0500 )edit

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I change the constant speed pump into a variable speed pump, but the result in energy consumption is still constant

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I change the constant speed pump into a variable speed pump, but the result in energy consumption is still constant