Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question

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

paulthebro gravatar image

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:

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

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

mikesweeney gravatar image

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.

edit flag offensive delete link more



A set of pump curve coefficients is listed here.

Eric Ringold gravatar image Eric Ringold  ( 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 gravatar image paulthebro  ( 2017-02-28 23:12:55 -0500 )edit

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

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

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools



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

Seen: 312 times

Last updated: Feb 28 '17