Re: [EnergyPlus_Support] Water loops, hydraulic separator, pumps

To start with, I would model the hydraulic seperator either with plate-water-water or waterheatermixed objects.

second, assuming roughly equal pipe network pressure drops, the rated head of P3=P4...then create one new pump instead P34 with this rated head. The rated volume flow should be that of P3+P4. Assuming that the fraction of rated flow expected for P3 is roughly the same as that of P4 during daily operation, your new P34 will be a good approximation.

With P1 and P2, I'm not so sure...if they are variable then typically P1 will run from zero to 80% at which time P2 turns on and both run at 40% (the bypass loop is just for safety).

If they are constant flow, then the bypass is regulating and the power remains constant whilst P1 is on and P2's constant power usage is added as soon as the total demanded flow exceeds the maximum of P1.

In both cases you could write an EMS to double the power out of P12 as soon as the total flow demand exceeds a certain flow rate. There should be an internal variable for this hopefully.

What does the headeredpump object do?

Mit freundlichen GrÃ¼Ã?en- Sent from my iPhone (excuse the brevity)

i. A.

Jean Marais

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Tel. +49 30 6706662-23

On 05.09.2013, at 17:09, <fpasserini.tn@xxxxxxxxx> wrote:

I have uploaded a schematic representation of the hot water loop that Iâ??m modeling: http://imageshack.us/f/35/mjdw.jpg/

The hydraulic separator can work as a bypass. Since the supplied water is warmer, if the primary and the secondary loops are balanced, the supplied water should remain in the upper part of the hydraulic separator.

I start modeling in DesignBuilder and it seems that I can model such a scheme:

http://imageshack.us/f/825/chp7.jpg/

In your opinion, should I change the scheme in EnergyPlus?

I know all the pump heads of P1, P2, P3, and P4. If I maintain the scheme of DesignBuilder, how could I evaluate the equivalent head of the pump? I think that I should know the curve mass flow rate vs hydraulic resistance of the water loop but actually I donâ??t?

Best Regards

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