Electrical Load for HVAC mechanical equipments

[julylee]

I am working on a project and it's at very early phase. It's a three-story office building with the area of 50,000 sq. ft. The building include offices, conference rooms, electrical rooms and a data center inside. I wonder if anyone could advise if there's any resource which provides guidelines for estimating the electrical load (for example, in KW per squire ft) from HVAC equipments for similar type of buildings? The HVAC equipment includs chiller, boiler, air-handling units, etc.

Thanks!