# of units

we are a bit confused on if we are factoring in number of units properly. at different compressor speeds and fan speeds different number of units will be needed to provide the 10kW - at 60hz low speed, less units are needed - so for cost savings analysis should we just assume there are enough units to provide the needed 10kW cooling capacity?

You are correct that based on the compressor and fan speed you are looking at, there may be different numbers of units that are necessary to run...this will have to be factored into your cost savings analysis. The number of upgraded units that are required to run compared to the base case will result in a cost penalty ($150 to upgrade compressor, $125 to upgrade the fan for each upgraded AC). This penalty will obviously take away from the gross electrical savings.

The task letter isn't talking about buying new AC units...they already have plenty on site, the only question is if they should spend the money to upgrade their existing units based on the specifications they provided to you.