shop package unit

[saon]

I have a 60x80x12 shop, split into 3 sections, 1 is 60x56 with 1-14x12 overhead door and 2 are 24x30 sections separated by slider door. front room has a 10x12 over head door. both doors are commercial insulated doors with good seals. does have a few 3x3 windows.
its batted insulation in walls and steel siding inside and outside. ceiling blown in cellulose approx. 15" deep.

looking at a 5 ton ac only package unit. building is in northern Indiana. its auto shop so it doesn't need to be a freezer but comfortable and get rid of the humidity. I already have a hanging gas heater in each of the rooms so heat isn't a concern

planning on mounting it outside the 60x56 area in the corner next to the 1 of the 24x30.
will run the supply and return through the wall and up to the ceiling and then round duct along the wall with registers 40' or so?
pointing into the main shop and thinking of poking 2 thru the walls into each smaller rooms.

questions are:
duct size?
the supply out is 14x14 so feed that into a 18" round spiral. up the wall rectangle and transition to round along the ceiling?
return is 24x12, where should it be? floor, middle, ceiling? does it need ducted protruding into the room or flat against wall ok?
how do I run the duct thru the wall? there are studs every 16".
do I make a duct sleeve to go thru it for the supply and then cap off 2 stud cavities for the return?
says 40 amp circuit with a 60 amp breaker. needs to go 100' so its looking like I need 6 gauge 3 wire with a ground correct?
what else don't I know that I need to know?

I am pretty handy and have a sheet metal brake and tools to do about anything needed, or ill buy what makes sense to buy.

Thanks for any help or insight anyone can provide.

 

[fitter30]

Your duct size is to small for 2000 cfm main trunk line would also reduce size.

https://www.google.com/url?q=https://hvacdirect.com/hvac/pdf/Field_duct-sizing-chart.pdf&sa=U&ved=2ahUKEwiNjYfdrcT3AhXJB50JHUIGD-MQFnoECAoQAg&usg=AOvVaw1fBA7jh_PsNFfTYgWh8mU4

 

[saon]

Your duct size is to small for 2000 cfm main trunk line would also reduce size.

https://www.google.com/url?q=https://hvacdirect.com/hvac/pdf/Field_duct-sizing-chart.pdf&sa=U&ved=2ahUKEwiNjYfdrcT3AhXJB50JHUIGD-MQFnoECAoQAg&usg=AOvVaw1fBA7jh_PsNFfTYgWh8mU4

that chart shows 20" round, i got my 18" from another chart online.
ill upsize to 20".
i do not know if it needs to stay 20" or taper down farther away after a few registers exit it or not?

also i assume ill need to insulate the exterior portion of the duct. no idea what to use for that?

 

[PoorUB]

As for the return, if your only concern is AC only, then run the return up as close to the ceiling as you can. Pull the heat off the ceiling. I would run the return duct into the building, then just straight up the wall. If there is a chance you might heat with it then also put in a return on the floor with a damper to control whether you pull air off the floor or ceiling.

i do not know if it needs to stay 20" or taper down farther away after a few registers exit it or not?

Your supply duct can go down in size as it goes across the building and as it goes past registers. Your register sizes and locations will dictate the CFM in the duct size required. You don't need to get crazy, maybe drop down once or twice. Say you use 10 - 6x10 registers then half way go from 20" to 14"

 

[saon]

As for the return, if your only concern is AC only, then run the return up as close to the ceiling as you can. Pull the heat off the ceiling. I would run the return duct into the building, then just straight up the wall. If there is a chance you might heat with it then also put in a return on the floor with a damper to control whether you pull air off the floor or ceiling.


Your supply duct can go down in size as it goes across the building and as it goes past registers. Your register sizes and locations will dictate the CFM in the duct size required. You don't need to get crazy, maybe drop down once or twice. Say you use 10 - 6x10 registers then half way go from 20" to 14"

no I won't be heating with it. the only option for heat is electric and that would be to exspensive to run. I already have hanging propane heaters.

thanks for the duct info. I was thinking aprox 8 registers or so.
I also assume that the end of the duct should be capped off, not just a register straight off the end correct?

 

[Yankeefarmer]

Have you considered using a heat pump package unit rather than cooling only? Wondering whether, in light of today’s pricing and supply uncertainties, a couple hundred dollar price differential to get heating capability might be worth it.

 

[PoorUB]

no I won't be heating with it. the only option for heat is electric and that would be to exspensive to run. I already have hanging propane heaters.

thanks for the duct info. I was thinking aprox 8 registers or so.
I also assume that the end of the duct should be capped off, not just a register straight off the end correct?

Cap it.

Depending on the register a 6x10 will get you about 200 CFM so you need ten of them.

 

[saon]

Have you considered using a heat pump package unit rather than cooling only? Wondering whether, in light of today’s pricing and supply uncertainties, a couple hundred dollar price differential to get heating capability might be worth it.

I'm past that stage I guess, I already have the hanging heaters up and running a few years now. and I already purchased the package unit.
options are good for sure, but money wise I'm only $2100 total into the heaters and less than a year old ac unit, and everything installed so far.