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Air Conditioning for Small Shop--Window Units vs Something Else

munruh

New member
I've been using a 25,000 BTU window unit in our smaller shop. It's a 40 x 60, but have a little over half of it partitioned off. It barely keeps up, but gave out last week. In the next year or so we plan on taking out the partition and it will be the full 40 x 60. I'm trying to decide if I should get another big window unit or look at a different option that will work for the 40 x 60 space. Ceiling is 14 ft. What would my other options be? Any experience?
 
O

otrlt

Guest
Your decision to cool the shop will save you thousands of dollars, in the short term. Don't go on the cheap here, If your running cnc's @ 85 degrees or higher, they will fail soon.

To give you an idea of what a unnoticed benefit of a cool shop is, machine coolant consumption will drop dramatically, that by itself will pay for electrical usage alone.
 

Bobw

New member
To give you an idea of what a unnoticed benefit of a cool shop is, machine coolant consumption will drop dramatically, that by itself will pay for electrical usage alone.

You only lose the WATER portion, not the expensive COOLANT part... I pay about a penny for 50 gallons
of water, and about $40 for a gallon of coolant.


Suck it up.. I saw just shy of 105 in here the other day.. Not a big deal when you are used to it.

I used to work in a shop out here with no HEAT or AC, and they had essentially NO DOORS.. STAGNANT
and HOT in the summer, FREEZING F'N cold in the winter.. I run pretty much from March to November
with the doors wide open.. Air movement helps a LOT. Even in the winter, doors are open most days,
but get closed at night.

It was 74 the other morning, and I put on a jacket.

Pic from WAY back before anything was moved in.. Its nice, its like working outside almost all the time,
nice view pretty much every direction.
1423270483_056b313e86_o.jpg
 

swatkins

New member
I have a 40 x 60 divided into three areas... One 2400 window unit for each...

One area is left at a constant 74 degrees and is 20 x 40 with a 14 foot ceiling.

Second area is app 30 x 40 with 20 foot ceiling and the AC is run only when we need it...

Third area is also a machine room that is 14 x 20 with 8 foot ceiling.

Using all three units is the best way I have of keeping the electricity bill under control as I can use only the units I need. If I need to keep the big space cooler, during a hot day, I just open up the man doors into the other spaces and turn all three units on...

Also having three units keeps the repair costs down. If one unit bites the dust the others take over until I repair it or replace it.. At 700.00 dollars a unit, it is the cheapest way I have found to A/C the building.

I have had one unit running for 8 years now and the only repairs have been a new fan motor..
 

CarbideBob

New member
Suck it up.. I saw just shy of 105 in here the other day.. Not a big deal when you are used to it.

Yea but is "dry" heat.
At my second job and it only hit 90 outside here.
Next to the carb furnaces my guys/gals showing me 120 on their thermometers in the work area but it was not so bad with decent airflow.
Heat treat people wear this as a badge of pride so they were not complaining just showing the new supervisor the intro deal.
Then it rained like crazy for an hour.
Now workstation temp is down to 90 at the furnaces but it is absolutely miserable.
30 degrees cooler but way worse to work in.
They tell me it will get worse so buck up and get used to it rookie....:dopeslap:

Not sure a/c saves coolant tank level. Perhaps the opposite. It dries the air and spits out water in a endless cycle.
Dry air absorbs more water.
Agree that either way it's water loss not coolant so the add on is just about free if you check your readings on concentration. (these little gauges are cheap nowadays)
Makeup is very little coolant and if you add at the "new batch" ratio you will end up so way high on coolant.

There is a difference between your people living in Michigan and living in Texas on temps and comfortable so one side sees the other as nuts or sissies.
I'm going with a buck five comfy and Bobw is nuts. :D. Give me the "think snow" thing.
Bob
 

Rob F.

Active member
...Not sure a/c saves coolant tank level. Perhaps the opposite. It dries the air and spits out water in a endless cycle.
Dry air absorbs more water.
Agree that either way it's water loss not coolant so the add on is just about free if you check your readings on concentration. (these little gauges are cheap nowadays)
Makeup is very little coolant and if you add at the "new batch" ratio you will end up so way high on coolant....
Isn't the condesate that comes off of A/C basicly distilled water? Is it a crazy idea to recover the condensate water back into the coolant tank? I mean if the tank is evaporating and the A/C is cathing that evap water....:scratchchin:
I only use coolant in mist sprayers so not much experience with large volumes of it.
 

CarbideBob

New member
Isn't the condesate that comes off of A/C basicly distilled water? Is it a crazy idea to recover the condensate water back into the coolant tank?
Yes it is, here in the great lakes state we have water... The problem is getting rid of it from our buildings and basements.
This all matters differently where you live in our great country.
Bob
 

swatkins

New member
Isn't the condesate that comes off of A/C basicly distilled water? Is it a crazy idea to recover the condensate water back into the coolant tank? I mean if the tank is evaporating and the A/C is cathing that evap water....:scratchchin:
I only use coolant in mist sprayers so not much experience with large volumes of it.

I would check the PH of the water before using it... I had to install a bunch of PVC drain pipes to take the condensate off of 20 roof mounted Package AC units. It seemed the water was just output onto the roofing membrane and ran off the roof into the painted and galvanized gutters. Rusted them out in 3 years.. We installed drains to each unit and ran them to the ground.
 

SND

New member
Ductless units.
They're not too much $ in the US and not that hard to install yourself if the contractors aren't reasonable.


The water off the condenser would be full of dust, polen, bugs, etc usually, not good.
 

munruh

New member
Ductless units.
They're not too much $ in the US and not that hard to install yourself if the contractors aren't reasonable.


The water off the condenser would be full of dust, polen, bugs, etc usually, not good.

any ideas what a ductless system will cost for a 40 x 60 shop?
 

Bill D

New member
A decent ductless system will be about twice as efficient as a window unit. They make them as heatpumps for winter if you do not have gas heat.
painting the roof white is the first step to keeping the building cooler.
Bill D
 

cnctoolcat

New member
Search Google, Ebay, and Amazon for "mini-split air conditioners" - a common name for the ductless units. These come in various sizes, and are the cat's meow.

All you need to install is a cheapo vacuum pump to evacuate the lines after hooking up. The outside unit contains all the refrigerant, and the lines attach with threaded fittings.

They are available in 120 and 240 volt versions, and various BTU ratings.

The inside unit mounts up high on a wall, has a remote control, and they are very quiet.

Also, you can buy them in the "heat pump" version, which produces heat during the winter as well as air during the summer.

Mitsubishi and LG are both big brand names in the mini-splits, although the other brands are a bit less money for the same size.

ToolCat
 

Tony Quiring

New member
Where is this shop and what is the weather and generated heat load?

These are just the starting questions.

In our area that would be 2400 Sq ft / (1 ton cooling per 500 sf) =5 ton or 60000 btu.

But tall building and insulation may require more.

That is only to combat natural heat load.

Now look at your electric bill...watts X 3.42 = BTU so do the math and divide by working hours and that should be estimate of BTU/HR of machine heat load.

Just tossing in a window unit not answer.

Ductless units can be used for " spot cooling" similar to how data centers are now being built where the cooling is built to server pods, a ductless unit can be placed in the center of a pod where the human works.

Seek out local commercial HVAC folks as they do this every day and can help you design something that works that will run the cheapest as well..

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 

packardbill

New member
Mitsubishi 3 ton split system. Works as heat pump, too. Call a Mitsubishi HVAC dealer.They'll do a heat survey and give quote. Some utilities here in the northeast offer rebates if installing the system. PB
 

Big B

New member
I just bought a mini split system for our cottage. Haven't gotten it installed yet but am planning on doing that shortly. It will heat and cool the cottage and from what I have heard from others they are super efficient for cooling and also for heat down to about freezing.

If it does what I think it will I am planning on putting one in my shop too. Right now I have a 35 year old hanging 75K btu natural gas furnace and a 18K btu window ac unit. I think it will save a fair amount on heating and cooling in my shop.
 
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