Norad's Chiller

[TheAMAZINGNorad]

Having started garther parts for a chiller this summer, I am finnaly at a point in which I can see light at the end of the tunnel. This is what I have so far:

Embraco FGS-95A Compressor
Matching Condenser
Spoorlan filterdryer
Spoorlan sightglass
Custom RX (1" dia x5" Cu)
Custom build Evap (3/8 coil shell in tube)
Spoorlan TEV
Schrader valves, fittings, ect...

I am getting to the point of brazing the entire system together, but had a few questions.

1) I read alot about SLHX and Desuperheaters in the various SS and DD builds, but are they applicable to Chillers? From what I have learned, SLHX increases COP by reducing liquid line temperatures and helps prevent liquid from entering the compressor. The downside is possible increased evaporator temperatures. As far as a desuperheater, I am still unsure as to its purpose, yet by its very name I take it it reduces superheat. More information would be appreciated

2) I have read how people use desuperheaters and other coils to reduce vibrations. As long as I include some u turns in the tubing, vibration should not be a problem? Correct assumption?

3) I am assuming that orientation of the filter dryer/sightglass is not important. As long as the reciever feeds liquid refrigerant to the TEV, I should be ok. Is this an accurate assumption?

I guess in general, I know what the basic parts of a refrigeration system do. I know how they should be connected, and in what order. This semester I have learned how to do cycle analysis on a refrigeration cycle, calulate COPs, and other textbook thermodynamic things. What I do NOT know, however, is all the little tricks of routing the darn tubing! Do I just connect it all straight shot? Does orientation of the parts matter, other than in obvious cases such as with the condenser. What would addons, like the SLHX and desuperheater, really do for MY chiller. That is what I need advice on now!

As soon as I can borrow my roomates digital camera I will take lots of pics of what I have built so far and what I have aquired. Till then, thanks for the help.

[Xeon th MG Pony]

Drop the SLHX, no point and added complexity, I found it added no noticible improvment to my system other then on paper (then again it isn't all that well built so that may be a facter, how ever I do not intend on bothering to add one next time).

Desuper heaters should be called vibration dampeners in our aplication, and having a vibration dampener is all ways good when connecting the compressor. I all ways use two to three loops to dampen.

3: Yes but puting the sight glass at a 45degree angle can help to tell whether liquid or gass.

[epion2985]

1) SLHE help improve the efficiency. However granted its no magic trick, its like using a turbo to introduce more air to your engine which wont do you any good if you don't provide sufficient fuel to go with it. In other words it doesn't just help in any case in any situation. But overall yet it helps improve efficiency, weather you will be able to have a significant improvement or not is dependent on the sizing, construction, and a system its implemented in. Go ahead and braze one it, it wont hurt you and its just a simple hx inline, worst case it wont help much, best case it will help handle loads more efficiently.

2) Desuperheater is somewhat of a retardation. Its a vibration dampener. The reason they call it a desuperheater is because they helped get rid of the superheat on systems that had undersized condensers, is a quasi ironic twist of fate. But yeah, do a few loops to help disperse the compressor induced vibrations.

3) Orientation of the filter/dryer is important. So much so many actually have it written on them or have a big arrow. You generally want liquid enter at the top and come out the bottom, so it needs to be somewhat vertical, if its at a 45 degree angle thats ok too.

[TheAMAZINGNorad]

1) SLHE help improve the efficiency. However granted its no magic trick, its like using a turbo to introduce more air to your engine which wont do you any good if you don't provide sufficient fuel to go with it. In other words it doesn't just help in any case in any situation. But overall yet it helps improve efficiency, weather you will be able to have a significant improvement or not is dependent on the sizing, construction, and a system its implemented in. Go ahead and braze one it, it wont hurt you and its just a simple hx inline, worst case it wont help much, best case it will help handle loads more efficiently.


I know that the liquid exiting the condensor is a, theoretically, subcooled liquid. So if we route that output to a HX which flows the liquid over the suction line, then we dont really care about the volume in which that fluid flows? In other words, if my suction line is 3/8 and my liquid line is 1/4, I can dump the liquid into a 1 & 1/4 ID copper tube with the suction line in the middle then reduce it back to 1/4. Am I ok on this still? Now, this is assuming liquid refrigerant behaves like water and is incompressible: pressure is a function of temp not area. So I would basically decrease then increase volumetic flow, but thats about it. Or, am I better with some sort of spiral HX in which I route the 1/4 inch liquid line though some 1/2 expanded suction line, or something similar?

I guess it does not really matter. After all, convection is soley a function of h, your Delta T, and surface area. H depends entirely on your fluid and its velocity, and our delta T is sorta fixed. So I should be looking to maximize surface area in contact with fluid flow. Assuming I cant change the size of my suction line, or if I do bad things might happen pressure wise since we are a gas, I need to design the appropriate length to handle a specific heat transfer. Should I am for like 50-100W? Am I totally overthinking this? Stupid Dr. Bittle. I always overdo.think everything with this class!!!!!

[epion2985]

Pressure is a function of temperature and volume. Increase the volume enough, like in the evap vs before metering device and poof, vaporization.

Just oversize it, make it easy on yourself and pick one up from doucette.

http://www.doucetteindustries.com/suction.html

[TheAMAZINGNorad]

As promised, some pictures of what I have minus the base for the whole thing. I am going to need to split this up into two posts. Sorry for the lack of updates, but I had finals and now I am home for Xmas so things have been kinda lax.

[TheAMAZINGNorad]

Round 2, until I can figure out why I can't access my school account to upload my pictures there.

[Corner]

Very clean, i like it, keep it up man :)