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A/C 3 phase or single phase

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TWD puller

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I am looking for a A/C package for shop. The figure says I need 10 tons for the whole shop. But all I am finding is 3 phase units. Surly they have a way to get these to work. I am not sure many neighborhoods have 3 phase power. HELP


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acmikee

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need more info is 3 phase available how much service do you have available after all of you equipment is installed is the bldg. divided so you can split the units up
 
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TWD puller

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Shop is 6000 sq ft. 16’ walls.

I am running my power now and come up with

This is figuring 50 Amp1 ph for a/c included in this.

Breakers needed

50 Amp 220 1ph = 2
40 Amp 220 1ph = 1
30 Amp 220 1ph = 1
20 Amp 110 = 10. ( may be able to reduce this. I am running all LED lighting and just need to figure what would be on when lights are as well)


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TWD puller

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I still struggle with the figures on BTU. We are in Florida and we are going to run de humidifier full time in shop. Also have a 16’ big *** fan. With the ICF and blown open cell on back side of roof that the standard BTU measurements work for this building. I think it should be less then 120,000 BTU


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TWD puller

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Couldn’t sleep last night. So stayed up and worked on this. Found this pkg would work great but will take two of them to get me where I need to be. I wonder how that will compare with to standard a/c of 5 ton each with air handler and duct work.

Any suggestions please let me know

8fc86942c97f922115d2f7c526ac111d.jpg
://uploads.tapatalk-cdn.com/20200627/8fc86942c97f922115d2f7c526ac111d.jpg[/IMG]
 
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brewchief

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In the past it was common to twin two furnaces or air handlers so you could run both into one duct system. To get 10 tons of A/C you'd be using to 5 ton units which are easily available in single phase. A twinning kit was used that made sure both blower motors started and stopped at the same time, if they try to start at different times the airflow from one can start one spinning backwards and then when it gets powered up it can kill the motor. The use of constant torque and variable speed blower motors has made this a bit tougher so any equipment that you are looking at you want to make sure the manufacturer has a twinning kit available. With two separate units twinned you also get the abilty to have two srages of A/C, if the twinning kit doesn't provide for a staggered start of the condensers I add a time delay relay so they don't start at the exact same time, even 15- 30 seconds is enough to cut down on lights dimming.

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TWD puller

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brewchief said:
In the past it was common to twin two furnaces or air handlers so you could run both into one duct system. To get 10 tons of A/C you'd be using to 5 ton units which are easily available in single phase. A twinning kit was used that made sure both blower motors started and stopped at the same time, if they try to start at different times the airflow from one can start one spinning backwards and then when it gets powered up it can kill the motor. The use of constant torque and variable speed blower motors has made this a bit tougher so any equipment that you are looking at you want to make sure the manufacturer has a twinning kit available. With two separate units twinned you also get the abilty to have two srages of A/C, if the twinning kit doesn't provide for a staggered start of the condensers I add a time delay relay so they don't start at the exact same time, even 15- 30 seconds is enough to cut down on lights dimming.

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I will check into that. And run the numbers. Thanks


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BillK

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TWD puller said:
Shop is 6000 sq ft. 16’ walls.
Click to expand...

I think you really need to get a pro in to estimate the size unit (s) you will need. The shop my business is in is 1800 sq ft. 30x60 with 15ft ceiling. It is in the middle of a row of units so it is pretty well "insulated" ? I have a 5 ton unit on the roof with an air handler hanging from the metal roof trusses. I would say it is just about perfect size. It keeps up fine on 95 degree days. I keep the shop at about 74 degrees. I am in Maryland and most likely nowhere near as hot and humid as you are in Florida.

I am not an HVAC engineer but I would almost think that 10 tons is not enough. Using the formula on the following sit comes up with a 10-12 ton unit for a 6000 sq ft unit with 8ft ceilings. You have double that height so not sure how much that adds.

https://www.sobieskiinc.com/blog/how-size-commercial-air-conditioner

And that is in the Delaware / New Jersey area
 
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theoldwizard1

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SE MI
TWD puller said:
Couldn’t sleep last night. So stayed up and worked on this. Found this pkg would work great but will take two of them to get me where I need to be.
Click to expand...
Ceiling cassettes do not do a good job a air distribution in large open areas. The are design for a bedroom, kitchen, smallish living room.

6000 sq ft, but what are the floor dimensions ? 60x100 ? You would easily need 5 air handlers on each of he long walls. I think you will need a couple of those Big *** 16' Fans.

Compare the SEER with a traditional central air system or even a central heat pump. 19 SEER is darn good for a big system !

One down side is maintenance. The filter on each air handler needs to be cleaned at least once a year, more if there is a lot of dust/dirt in the air.
 
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u3b3rg33k

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i don't think I've seen anything over 5-6 tons in single phase. I think you get a motor efficiency boost with 3 phase vs single phase as well. going that big I'd want multiple systems or at a minimum two stage units as well. I don't see a benefit to a single huge system unless it's cost, but you might not have economies of scale on your side here.
 
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Jim greengo

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brewchief said:
In the past it was common to twin two furnaces or air handlers so you could run both into one duct system. To get 10 tons of A/C you'd be using to 5 ton units which are easily available in single phase. A twinning kit was used that made sure both blower motors started and stopped at the same time, if they try to start at different times the airflow from one can start one spinning backwards and then when it gets powered up it can kill the motor. The use of constant torque and variable speed blower motors has made this a bit tougher so any equipment that you are looking at you want to make sure the manufacturer has a twinning kit available. With two separate units twinned you also get the abilty to have two srages of A/C, if the twinning kit doesn't provide for a staggered start of the condensers I add a time delay relay so they don't start at the exact same time, even 15- 30 seconds is enough to cut down on lights dimming.

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Click to expand...
What he said.
 
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TWD puller

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theoldwizard1 said:
Ceiling cassettes do not do a good job a air distribution in large open areas. The are design for a bedroom, kitchen, smallish living room.



6000 sq ft, but what are the floor dimensions ? 60x100 ? You would easily need 5 air handlers on each of he long walls. I think you will need a couple of those Big *** 16' Fans.



Compare the SEER with a traditional central air system or even a central heat pump. 19 SEER is darn good for a big system !



One down side is maintenance. The filter on each air handler needs to be cleaned at least once a year, more if there is a lot of dust/dirt in the air.
Click to expand...



Thanks for replying. That mini Split has five handlers per unit. The ones they talked about was 12+12+18+18+18. I would have 10 handlers in the open area. And yes the floor is 60x100. Only one 25x25 engine clean room and on my drawing I have one 12k handler in that room.


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nadogail

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Coronado, CA
Is three phase available in your location. IMHO, it is seldom found in residential neighborhoods and not common in rural areas. Be sure to check with your electric utility for your particular property.
 
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u3b3rg33k

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TWD puller said:
Idk that yet. I did look at a digital phase conversation today. If I did that I could go with a single a/c unit.


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you could get a 2 stage thermostat and set them up staged - just set stage 2 to a low CPH like 3 or so.

phase conversion like a single phase input drive. i guess that could work. you'll have to make sure you get the rotation correct or it won't work.
 
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