Q: I am an energy engineer at an ESCO located in Dubai, UAE.

My project is a high-rise residential tower with water-cooled chillers/cooling towers/primary constant-secondary variable chilled water pump configuration. The cooling network serves the whole building but the tenant spaces (apartments) are sub-metered for their cooling consumption using BTU meters from a third-party metering company. They are billed for their cooling consumption separately; however, the building's utility bills (electricity) cover the full building consumption.

For M&V purposes, I collect the utility bills monthly from the building manager and separately request the submetered tenant consumption.

My question is whether this method for savings calculation is legitimate. The equation I use is as follows:

Savings (kWh) = Baseline (kWh) ± Adjustments (kWh) - Verified Utility Actuals (kWh) + Submetered Tenant Consumption (kWh)

A1: If I am understanding your situation, your Savings equation is simply the Option C savings equation, so you are good there. But if I am reading this right, "Verified Utility Actuals" is the building's total electric use, right? The "Submetered Tenant Consumption" is a subset of the total building's electric use, or in other words, a subset of the "Verified Utility Actuals." So I don't think you want to add that submetered energy use into your savings calculation. This would be double counting that energy use. Those submetered data can provide you additional insight into the building's energy profile/energy use, but should appear in the savings calcs.

But maybe I am not clear on your situation.

A2: agree with Tracy. If your goal is to quantify whole building electrical savings, keep in mind your measurement boundary. The chilled water use is within the boundary for a whole building analyses, so you would not include the “Submetered Tenant Consumption” in your calculation.