Sizing commercial HVAC systems

[HAL9000]

Does anyone know how to estimate a required size for a commercial HVAC? I'm having very limited sucess finding the info I need for my electrical design project and need info on what size of a system I would need for a 7 floor (6 above grade + basement) office building, 14,400 square feet per floor, 100,800 sq ft total.

Any info, directly, helpful web links, etc would be greatly appreciated.

I will need data on electrical consumption, input voltages, motor HP ratings as well.

[HAL9000]

So far, I'm finding (keeping in mind, this is just an esitmate for a theoretical building) somewhere in the area of a 120-125 Ton capacity.

[David M]

I would think it would also vary with the buildings energy efficiency and the climate where the building is located. It would also vary by how much waste heat is created by its occupants as well. Also what temperature the building needs to be maintained and at what times of the year. It would also vary by whether or not it has a smart system for maintaining temperature, or dropping temperatures such as in unoccupied rooms. It would also vary by how much these rooms are occupied.

I think there are quite a few variables that need to be calculated.

My brother designs HVAC systems for commercial buildings a living. I know he uses software to make these designs. These systems are all run by computer now in order to save energy. I will ask him.

[acr98disc]

Originally Posted by HAL9000 So far, I'm finding (keeping in mind, this is just an esitmate for a theoretical building) somewhere in the area of a 120-125 Ton capacity.

HVAC efficiency is measured in BTU's. British Thermal Units. (as well for the vehicles)

BTU Calculator

[HAL9000]

Originally Posted by acr98disc HVAC efficiency is measured in BTU's. British Thermal Units. (as well for the vehicles) BTU Calculator

Yes... I understand that, but since this is a design project for an Electrical Engineering Technology course, and not an HVAC course, a VERY rough estimate will be fine. I finally did find one site with all the specs for varying units, so I went with 2x 75 Ton units... my instructor needs to go over my load estimation on Monday anyway.. and I have everything in a spreadsheet so if I make a change to one number, it will automatically adjust everything for me, so no big deal now if he tells me that is too little, or too much.

Originally Posted by David M My brother designs HVAC systems for commercial buildings a living. I know he uses software to make these designs. These systems are all run by computer now in order to save energy. I will ask him.

That's why a range is more than sufficient... it's really kinda stupid, but for this project, I have to be an Electrical Engineering Technologist (fine, that's my course), a CAD Tech as all my drawings must be in CAD, an Architech as I have to design my building, a Civil Engineer as we need to have the civil drawings made for our building, plus estimate needs for HVAC, water pressure and pumps, elevators, know design code for entrance ways, stairwells, emergency exits... I somehow think this course is a little more involved than Electrical Engineering Technology... oh well... 33 more days.

[David M]

So there is no calculation for the thermal efficiency of the building?

Do it for the Icehotel.

https://www.google.com/search?q=ice+...w=1311&bih=910

[bob]

400 to 600 sqft per ton.

[David M]

Originally Posted by bob 400 to 600 sqft per ton.

A ton of lead or a ton of feathers?

[HAL9000]

Originally Posted by bob 400 to 600 sqft per ton.

Ok... I set up my estimate at 150, but at 600sq ft per ton, should be 168... at 500, it's 200, so maybe I'll up it to 2x 100.

[bob]

Originally Posted by HAL9000 Ok... I set up my estimate at 150, but at 600sq ft per ton, should be 168... at 500, it's 200, so maybe I'll up it to 2x 100.

Gotta check my slide rule...... "Yep the numbers sound good"

[HAL9000]

Well, at least if I learned one thing in this course, do stuff like this on a spreadsheet... tossed in the new numbers, it automatically calculates the KVA, total system KVA, Amps, Total Amps, etc

[bob]

I assume they do not care about availability of 100 ton units or climate zones.

[HAL9000]

Nope