MLM,

but if you are going to build a new building that needs heated and cooled an ideal design is like the one below; a 80' x 100' clear span red iron frame with SIP cladding, roof purlins at 12 ft. oc. , white interior skins are very reflective and in this picture it is only natural lighting, as electric is not to building yet

MLM - Just our of curiosity, what is configuration of your first phase? 

Is it clear (column free) span across the 54' dimension? 

Is there an advantage to a column free interior?   Flat roof?  I assume snow load is a factor where you are.

What winter temperature do you want to maintain?  Just freeze protection?  or some level of worker comfort in the warehouse portion?

Skylights or clerestory windows (a strip of windows just under the roofline) do a good job of providing daylight into the interior spaces of warehouses.

Chris - What is your experience with flat (or very low slope) roofs with SIPS?

Bruce

I was trying to understand the structural system and whether or not it had a flat roof.

If I understand correctly, it does have a flat roof and there are no intermediate columns (i.e., 1 span of 54' instead of 2 spans of 27').  I will also guess there are bar joists or trusses spanning across the short span of building with metal deck, insulation and roofing membrane.

Since you need cooling, you will probably need a rooftop HVAC unit will supply hot air or cold air as needed through distribution ductwork to various points on the interior.  I think you can do this with one unit, but you might consider splitting it into two units to provide some back up and redundancy.  The office/showroom should have a separate system.  If you have a boiler (see below), you could use hot water heating and a split system for airconditioning.

Hopefully the ductwork can be done within the truss space so it does not impact your usable height.

A rooftop unit is essentially a self contained heating, ventilating and air conditioning unit (also called a "package unit", because everything is in one "box") and there are a variety of different configurations.  The simplest is an air cooled, direct expansion (DX) to provide the air conditioning.  Heating possiblities include electric resistance (coils of wire) or hot water coils inside the rooftop unit in conjunction with an electric, gas or oil fired boiler.  Rooftop units with heat pumps are available, but you will need pure heating in any case.  If you did not need airbconditioning, the normal warehouse solution would be ventilation fans with electric or hot water "space heaters".

You really need to have a good engineer or HVAC contractor lay out the options for you.  The efficiency of the units has a significant impact on first cost with an offset for lower operating costs.  A unit with 100% outside air capability (to permit you to use "free cooling" when weather conditions permit) would probably be beneficial in your climate.

If you have a boiler, you will need space for it.

In any case, your structure should take into account the weight of the rooftop unit and you will need a way to access it for maintenance.

Since you have a warehouse, you probably have one or more loading docks with high bay doors.  You should consider making a vestibule for your loading/unloading operations.  This will help minimize your heating and cooling load and improve comfort. 

Many warehouses also use ceiling fans to prevent stratification (temperature differential between floor and ceiling), but you must be careful of your clearances.

You have a big volume to deal with and minimizing the heating and cooling loads are really important.  Having a roof with a high albedo (light colored, reflective) surface will save on AC unit size and running costs.

One last thought.....natural light (skylights or clerestory windows) provides a much better working environment than artificial light.

(Chris..thanks for the links.  I wasn't trying to hijack the thread)

Bruce