Aggregated Campus (Building & Utility) Efficiency against fixed baseline (Ambient,load,demand,et

[Mansoor1982]

This is a challenge given by one of our customers. Here it goes.

We have the following HVAC systems & controls in a building:
1. Water cooled chillers, Primary pumps, Secondary pumps, Cooling Towers, Make up tanks
2. Air cooled chillers, Chilled water pumps
3. Air Handling Units
4. Heat Recovery Units or Energy Recovery Units
5. Variable Air Volume Boxes (for Zone Control)

Type of the building: Software Block & Utility Block

With the controls, we are able to calculate the following:
1. Individual equipment ikW/Tr for Chillers as well as overall plantroom ikW/Tr - Efficiency.
2. Energy Efficiency Index (EEI) of the building - kWh/m2/year
3. Design efficiency of the 3rd party integration equipment like UPS etc.

While we have individual efficiency of each system, the customer wants an aggregate of all this into a single graph with respective to selectable parameters (like efficiency at a certain ambient condition or at a certain load etc.).

Would appreciate if any one of you have done something similar to this and any guidance is highly appreciated.

Regards.

 

[willard3]

There Are too may variables in this, all interdependent.

 

[Mansoor1982]

Yes sir, that's why it was put to us as a challenge. We are also trying to wrap our head around this so we could find something useful for our customers.

 

[MFJewell]

Eff=Wout/Win

If it were me, I would get temps, pressures, mass flow rates, and working fluids for each system. Use enthalpies to evaluate the cycle as a whole. If you already have efficiencies of each subsystem, you may be able to use a ratio of mass flows to get overall efficiency, but I'm not 100% sure of that.

I am picturing something similar to combined cycle power plant efficiency where you take data from the Brayton cycle and the steam cycle to get overall efficiency.

 

[Cry24]

Most HVAC software can provide such a graph in energy modeling.
It gives you a profile for the year, month by month.

Get your HVAC guy to model the building (Trace 700, Carrier E20II; Energy Plus, Equest) and fairly simple to get what you're looking for.

 

[dbill74]

With all the variables, sound like something a database would be good at. MS Access maybe?

 

[immsk]

if you have kW/Ton for the plant, why don't you plot that against cooling degree days over the year and that should show you how the plant efficiency varies against the cooling load.