Project Snow flake

[flocko]

Good point. If there's a leak there would be a gallon of coolant on the floor not in my computer. DONE!! chiller goes on floor. Thanks

[Jason]

Bump for re-open.

[flocko]

WOOT !! project Snow Flake re opened !! Thanks Jason.

Well folks it's been a LOOONGG time since the last post on the "flake". Economic times have hit us all hard as Drew has pointed out to me and in turn has hit the forums activity hard as well.

Dusted off snow flake and brought out all the remaining parts and still have a few small ones to get but nothing major. Will be drilling and mounting all internals as I have finalized the positioning of most all parts. This week end I will have some updated progress photos to post. PLEASE post and ask questions.

[ShrimpBrime]

Right on. I'll be subscribed.

[flocko]

well I did not exactly make the week end post that I promised but here goes . Basically what I have done is attached all the mounting hardware to the res. and temp mounted res. in case . Top lid screws are just temps as stainless will need to replace the steel screws so they don't rust. Tapped and mounted the heat plate exchanger. Tapping all ten of the res. lid screws was a pita as stainless is hard as hell to drill. Enjoy and please post

[flocko]

Kind of in reverse order but you can see what led up to the end result. Pictures show the brackets and sealing / fastening method used on the res.

Next up will be the insulation of res. and then drilling the fill port hole in the top of snow flake and permanently securing the res. Enjoy !!

[boshuter]

I don't think I've ever seen anyone use a res and a plate heat exchanger in the same build. Do you plan to pump directly from the plate HX and just use the res as a kind of holding tank? I would think it would be much more efficient to have used a coiled evap inside the res and eliminate the plate HX alltogether.

[Drewmeister]

The res is a holding tank for the chilled liquid and is there to buffer the temps when the compressor cycles off the thermostat. It is actually very efficient as the compressor will only need to run a fraction of the time per hour to maintain temps. The plate hx is very efficient and will help provide quick pulldown times.


Order of cooling loop for this particular chiller will be. res->pump->waterblocks ->plate hx->res. This order will give the most accurate temp control and provide plenty of head for the pump.

Glad to see you back flocko.. looking good!

[flocko]

Boshuter : yes you have seen this set up before . If you followed Drew's SA450 build log you will see that he tested the evap in res with a plate heat exchanger and found no real difference in performance. The reason in this build for the unusual set up is lack of planning on my part and "built myself" into a corner were space would not allow the evap in res . which is what I would have preferred. The visual effects without the evap. in res. will not be as good but the end result will hopefully be the same.

Just a few pics of tonights work . Mounted the pump , which gave me a fit with not being able to mount the base without the pump because of the direction the pump has to slide onto the base from the rear. Had to get some coarse thread tapps and tapp base from the bottom . THE REAL MONEY hole in this whole project was the one thu the top of snow flake from the spout of the res. Not perfect but darn close and put a rubber grommet around hole to prevent vibration and scarring of the copper fill tube

Thanks Drew trying REAL hard !!

[flocko]

Not to be confused by the deception of the pump picture... the 90 degree fitting on the pump suction side IS NOT going to heat exchange . Photo's can be deceptive . Not sure if the 90 degree on suction side of pump is good ...may put a hard bend to the res. but @ .59 cents a piece , I can alway's change it . Final ac copper pipping arrangements will dictate weather I change this to a "straight" or leave as a 90. Time will tell. Wanted to be clear on this issue

[Drewmeister]

I take it you weren't able to trim and recess the fill port under the top.. maybe trim the nipple and ftg or use a different one?

It's ok to have a 90 degree bend on the inlet but it must have sufficient inner diameter and a gradual radius to it. The problem with some of those plastic ftgs is the reduced ID and lack of radius. It might not be a factor on this system though since final flowrate of loop may be closer to 1gpm. You can test the pump at 2gpm flowrate and see if you get cavitation or not. If possible go with a straight ftg or larger radius elbow.

[boshuter]

I wasn't trying to criticize the design guys..... I really hadn't ever considered using a plate HX with a res. Every chiller I've had was always just a plain coiled evap inside a res. I am definitely a fan of a res in any chiller build. I'd try this but the only plate hx I have is earmarked for a cascade.

This is looking very clean flocko.... thats a really good looking stainless res. I feel for you drilling the holes in it, don't know how many drill bit's I've went through drilling holes in stainless

[flocko]

Originally Posted by Drewmeister

I take it you weren't able to trim and recess the fill port under the top.. maybe trim the nipple and ftg or use a different one?

It's ok to have a 90 degree bend on the inlet but it must have sufficient inner diameter and a gradual radius to it. The problem with some of those plastic ftgs is the reduced ID and lack of radius. It might not be a factor on this system though since final flowrate of loop may be closer to 1gpm. You can test the pump at 2gpm flowrate and see if you get cavitation or not. If possible go with a straight ftg or larger radius elbow.

The top of the res. is so close to top of case that I could not cut the tube off because the pipe cutter hits the lid before I can get the lenght I want. I have since cut it shorter but still sticks thru top of case. I don't like it either . The fill fitting has threads in it for a sealed bolt . That's why I used it. Gonna think on this one !! Not brazed yet.

Pump fittings i.d. = 7/16"
Would you reccomend a different fitting for the pump... Perhaps brass ??

Boshuter : No insult taken ... glad to have the questions and posting . Keep it coming !!! Yes, Drew did a GREAT job making the res. Including the feet there are about 20 holes that were drilled in that res. and three drill bits later I was done !! Really should have a drill press.

[Drewmeister]

The 7/16" ID sounds good. One cobalt bit would last for drilling out quite a few of those reservoirs. Use plenty of drill oil/coolant and you must have correct speed and pressure or you burn bits.

Bo: No insult taken here either. I was just explaining the efficiency of this type of setup in general. If you're finding coiled evaps more efficient then I'm all ears. Perhaps more efficient use of space or cost wise?

So how did the fill port turn out?

[flocko]

First pic is the best I could do with available fittings. Lowered the spout about 1/2" from previous post but this is a failure on the flake I will have to live with and will do better on next build

Second pic is that killer stainless res. Drew made all covered up with ugly Aramaflex .

Third pic is "new" true 1/2" piping arrangement for pump . Drew : last plastic pieces were only 3/8" i.d. after I measured with my glasses on

Fourth pic. is what I would call a decent at best second attempt at brazing. Should work for low pressue water flow.

Fifth pic is what happens when you get flame adjusted right but hold tip of inner flame on copper and for to long. Funny thing.. that hole was on the bottom and for the life of me I could not figure out were all that brazing rod was disapearing too !! Edit : Just noticed fith pic is too dark . That's a hole burnt though that fitting and it was the only one I had.

Thanks for the look see and all you posts

[boshuter]

Originally Posted by Drewmeister

Bo: No insult taken here either. I was just explaining the efficiency of this type of setup in general. If you're finding coiled evaps more efficient then I'm all ears. Perhaps more efficient use of space or cost wise?

I can't say coiled evaps are more efficient, that just all I've ever used. I have never tried a plate hx for a chiller, the only ones I'd rememberd using them did not have a res and I never did care for that idea. I was always concerned about the water not spending enough time in the hx, kind of like the water in a car, in a race care without a thermostat they use a flow restrictor to slow down the circulation or else the water doesn't spend enough time in the engine to remove the heat.

I think the res with plate hx is much better, my concern was the coolant has to start warming up in the res even with good insulation..... in reallity it probably isn't enough to matter.

BTW; did you ever get a chance to try any of that new r502?

[flocko]

Well, spent the last three nights tieing in all the water side of the cooling lines in Snow Flake.

Soldering copper lines was a new experiance for me and most of them turned out well . However I did back them up with a thin coat of J/B Weld for insurence. I found it quite difficult to solder with the acy/ox set up as I just could not get the flame small enough to keep it tight in one place and not over heating the copper. After I ran out of both gasses I finished up the last three connections with the propane toarch and WOW what a huge diff . Those were the best three joints of all !!
If your following the thread you will see by the recent photos that I have switched back to plastic fittings on the pump. I drilled the 3/8" fittings out to 7/16" so they would have good flow.

Lastly.... Thought I would throw a photo of the whole system installed for teaser purposes.

Enjoy as I have and please post!!!!

[flocko]

Couple more for fun and you can see the brass plug I added to the res. fill port. Havin fun !!

[Drewmeister]

Glad you switched back to plastic fgs.. the metal ones can crack the inlet on the mag pumps. Yep.. just need propane or mapp for soldering the waterlines. Mapp can braze almost all those refrigerant line joints with ease using high silver brazing rod like that 45%.

I made a quick photoshop of how you may want to pipe the refrigerant lines. The u-bends will help reduce vibration from the compressor. If you are using a TXV then make sure to have about 2" of straight tubing off the upper evap ftg for the sensing bulb. Keep in mind that the TXV may require more receiver volume than the filter/drier can provide. If space alows then I would try and get a mini receiver in there. I'm sure captube would work fine for this unit too.

Great job as always!

[Neox69]

Very good read... Keep up the good work.