Homemade air handler 1

[NEPTUNE WATER]

Hey guys, I am a chemical water treatment technician out of Atlanta. This is actually a question for a project Im doing for my Jiu-Jitsu academy. I'm building an airhandler with 200ft of copper tubing that goes around a 44" diameter warehouse fan. I already have the 1/4" tubing ziptied in place and hooked up a small 400gph fountain pump. The psi was not high enough to push the water through fast enough. I need help/recommendations on what kind of pump to use. HP, GPM, PSI? needs to go through roughly 200ft of 1/4" OD tubing at 1-2'/sec. Thanks!

 

[NEPTUNE WATER]

I will be removing about 50ft of the coil possibly even more. Ive had success at this in the past with smaller fans using 100ft of coil and a small fountain pump. My intentions are to nix the fountain pump and try another pump option. What would have to be done to make this work?

 

[NEPTUNE WATER]

With the small fountain pump the water would still go through the coils fully but at way to low of a flow rate.

 

[bimr]

Type K 1/4-Inch tubing has an ID of 0.305. That would allow a pressure drop of approximately 70 psi when flowing at 2 gpm through 150 feet of 1/4-Inch OD tubing.

If you want more water flow, suggest you manifold 3 lengths of 50 feet long tubing in parallel. The 50 feet section has a pressure drop of approximately 25 psi. That would give you 6 gpm.

 

[NEPTUNE WATER]

Thankyou so much for your help! We won't be able to create a manifold since the copper coil is already set in place. So, we will likely go with a higher pressure rated pump. Do you by chance have any actual pump recommendations for a 70+psi pump at 2 or more gpm that woould work for this application. Also, assuming we keep the 150-200ft of coil, opposed to removing a large section.

 

[pmover]

look into the Grundfos product line at:

https://www.grundfos.com/products/f...tle&view=xml&x1=page_category&x2=applications

 

[bimr]

You can probably use one of the positive displacement type pumps that are used for pressure washers.

http://www.watercannon.com/p-1805-2...EVGYnpmuKtGX28_q-FFi_5rgwuxdHL3RoCjAsQAvD_BwE

https://www.google.com/search?ei=Tf.....35i39k1j0i67k1j0i131k1j0i10k1.0.I5JOMcjYzgY

 

[moltenmetal]

I wouldn't assume it's 0.305" OD tubing, I'd assume it's 1/4" OD tubing, likely 0.028" or 0.035" wall, annealed copper, of the sort you can buy at the hardware store. The flowrate through a 150' or 200' long single length is going to be really low at a reasonable pump discharge pressure drop. You need to divide this up into a larger number of parallel coils of equal length to make a pump a feasible option.

 

[bimr]

I wouldn't assume it's 0.305" OD tubing, I'd assume it's 1/4" OD tubing, likely 0.028" or 0.035" wall, annealed copper, of the sort you can buy at the hardware store.

If the tubing is 1/4" ACR refrigerator tubing, the ID is smaller at 0.19". The headloss for 3 - 67 feet long parallel sections at 0.67 gpm each is approximately 60 psi.

 

[moltenmetal]

You need to either take that coil off and turn it into a number of parallel flow paths, or you need to compromise- a lot- on the flowrate.

If this is 1/4" OD, 0.035" wall copper tubing, and you wanted to stuff 2 gpm of room temperature water through a 200 foot long coil of it, you'd need about 1400 psi. If your intention is to use the water for cooling, the 1400 psi pump will add so much heat to the water that you'll end up doing the opposite, i.e. the coil will very likely be transferring heat INTO the air.

The whole design is flawed. Even if you were to get 2 gpm through a bunch of parallel coils, the coils are just wrapped around a fan housing. There's not enough area to transfer a significant amount of heat out of the air into the fan housing. To be effective, the air needs to blow directly over the tubes- and to be even more effective, the tubes likely need fins on them.

 

[LittleInch]

That was going to be my question - i.e. what flow and temperature difference are we talking about here?

The actual ID of the tubes you're' talking about is critical to establishing what the pressure drop is which starts with the flowrate. So please define the actual tubing you're using

All I've seen so far is "1 to 2 feet per second" of water flow. That's a four times difference in pressure drop right there from 1 to 2. I don't know where 2GPM came from.

How many feet of pipe is actually going to do any good? You need a decent delta T in order to generate a heat transfer from the water to the air. as soon as the temp difference goes down as the water travels along your transfer rate drops at the same rate.

So you might have 150 ft, but in reality there might not be much benefit in more than 50 feet or perhaps even less.

Do you have a picture of this set-up?

MM is correct, using a high pressure pump will add heat and energy to a system which might be more than the cooling...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[NEPTUNE WATER]

Just uploaded pictures. It currently has 175ft of copper coil. We intend to remove at least a 50ft section. The incoming water will be at about 35 degrees F and we are looking for a deltaT of about 10-15.

 

[NEPTUNE WATER]

Fan picture

 

[LittleInch]

Ok,

So your pipe ID is apparently 0.19" diam.

There is no way this is efficient. You have three in line connectors. Just replace these with elbows and create three 50 foot lengths. Then it might work.

about 90% of your cooling will happen in the first 50 feet. The rest is just a waste of copper.

Re pipe this to be three parallel systems.

How much pressure you need for your flow of 1 to 2 feet per second - no idea - go look up some charts on pressure drop in small bore copper tubing.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[EdStainless]

Since you have connections take the suggestion by LittleInch and split the flow.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[chicopee]

I am not bothering with the calculation but if you can pump the GPM that you want with enough pressure to get the flow throughout the 175', perhaps there may be enough friction to heat up the water a little. You'll need an engineer to figure out the pressure at the inlet and the amount of heating from friction before you select a suitable pump as mentioned above of the positive displacement type. As mentioned above pressure washer pumps is perhaps a suitable type. Another type of positive displacement pump, is the type used on trucks for their hydraulics. Another concern the amount of pressure that such hose can take without rupturing. You'll need guidance.

 

[MortenA]

@Neptupe,

When considering Littleinch's fine proposal you should consider that the increase in flow will be equal to the increase in flow area squared! So splitting the flow in 3 will increase flow by a factor 9! Furthermore, you will have three location with a high temperature difference between the water and the air - this will improve heat transfer as well!

Best regards, Morten