Shop air conditioning ????

[Jackfre]

You need to get a "real" heat loss/gain on this building. Not doing so is hoping you can hit the hole on the rolling donut. Once you know what the load is, you can better select your options. I remain a fan of the mini-split heat pumps as they are all inverter controlled, meaning variable speed with attendant efficiency increases. Standard sizing for commercial buildings use the old rule of thumb of 400 sq ft/ton (12kbtu) of cooling. Does your foam increase or decrease that? Only the heat/loss gain program knows for sure.

[BadgerBoilerMN]

A proper heat load takes into account the volume, exterior surface area, windows doors, insulation and infiltration. Not to mention, orientation, inside and outside design temperatures. Oh yes, the latent, as well as sensible heat are considered. A swamp cooler may work for dry climates.

A mini-split heat pump is nearly always the most economical to operate (window shakers representing the very low end) and how "big" the space is represents just one component of heat load analysis. A properly sized AC unit will be more efficient at removing the latent heat than one that it over-sized.

5 tons, really? Why guess?

[pseudorealityx]

You forgot the internal loads. People, lighting, equipment.

[BadgerBoilerMN]

Yes, thank you.

[skyking]

Originally Posted by BadgerBoilerMN

A proper heat load takes into account the volume, exterior surface area, windows doors, insulation and infiltration. Not to mention, orientation, inside and outside design temperatures. Oh yes, the latent, as well as sensible heat are considered. A swamp cooler may work for dry climates.

A mini-split heat pump is nearly always the most economical to operate (window shakers representing the very low end) and how "big" the space is represents just one component of heat load analysis. A properly sized AC unit will be more efficient at removing the latent heat than one that it over-sized.

5 tons, really? Why guess?

Thanks ,but that is a little over my head. I just want it cold enough to get my wifes nipples hard !

[Jackfre]

I get you man! You do have style. Just consider it foreplay

[BadgerBoilerMN]

I design condition not listed in any of my books but a subject for an ASHRAE white paper perhaps

[Jackfre]

Originally Posted by BadgerBoilerMN

I design condition not listed in any of my books but a subject for an ASHRAE white paper perhaps

...assuming you are volunteering for hands-on testing?

[Big_Jim]

So....Is an 18500 btu window unit overkill in a 24X30 with 12' ceilings?

[Big_Jim]

Originally Posted by Big_Jim

So....Is an 18500 btu window unit overkill in a 24X30 with 12' ceilings?

Anyone??

[ksj9393]

As mentioned by BadgerBoilerMN earlier in this thread, there are a great many factors beyond mere room volume that go into A/C sizing. If you want a veracious answer, would need to know design delta T, wall/ceiling R values, infiltration, solar hear gain, etc.

If you want an off the cuff answer, I would say no... 18500 BTU is not likely to be too large. It may even be too small.

[Big_Jim]

Originally Posted by ksj9393

As mentioned by BadgerBoilerMN earlier in this thread, there are a great many factors beyond mere room volume that go into A/C sizing. If you want a veracious answer, would need to know design delta T, wall/ceiling R values, infiltration, solar hear gain, etc.

If you want an off the cuff answer, I would say no... 18500 BTU is not likely to be too large. It may even be too small.

Design delta T? (Excuse my ignorance) But I have no clue what that is. I'm in the process of building the garage we are going with R38 in the ceiling & R19 in the walls with a complete vapor barrier and sound deadening on the ceiling as my Mom will be living above me and I don't want to disturb her with noise or fumes. Infiltration? Again (clueless)! As for Solar heat gain; I think you mean light from windows & radiant heat from garage doors & things? There will be no windows as I'm mostly below grade (on 3 sides). There will be one door leading to outside & one door to the inside both sealed fire doors (Code). The garage doors will be the best insulated ones I can get. I hope all this gives you a better idea of what I'm doing or at least trying to do and better help answer my question.
Thanks
Jim

[Big_Jim]

Oh and the wife wants me to put 2 ceiling fans in as well. Don't know if that makes a difference.

[pseudorealityx]

Delta T is the difference between 2 temperatures. For instance, some people want a garage that's just 'better than nothing', and low 80's is fine, since it's 100+ outside. Others want to be able to keep it cool like a house, mid to low 70's. Obviously you need a larger unit to push the temps down more.

100 - 80 = 20 degree delta T
100 - 75 = 25 degree delta T


Infiltration is how leaky the space is. You want to minimize the drafts, so good weatherproofing around the doors, any windows, etc.

[Big_Jim]

It will have radiant heat in the floor & insulated so good I'm hoping to be able to heat it with a match. Looking to keep it like I keep my house a cool dry 72-74 deg. year round. No excuse not to work on my hot rods then.