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I hope the first stage can deal with the quite big compressors in the second and third stage.
Bazx, from a economical point of view it would be better to use R-134a + R-23 + R-14.
But if a already had the R-507 and R-1150 at home i would use them too.
@NoL: i didn't mean the count of 3stager units, it's the trend :D
@Bazx: what i forgot to say: i really like the idea of the mobile "case"
For what refrigerant are second and third stage compressors made?
Quote:
Originally Posted by before
hehe i have been following your lead:D
@godmod as you say i have the 1150 and the 507 but i also have the 23
i am going to put shut off valves in the second stage before the hx as i think i will be trying different lengths/dia of cap for this stage getting the temps right for r14 in the third stage and i don’t want to be vac-ing down and recharging all the time
i was also thinking about thisQuote:
Originally Posted by Moc
so far i have found the 12 plate can hold load well and have yet to over power
this size but there is always a first time and i might just go for a 20 to be sure
how! An other beauty monster from you for sure!
wow this one looks like its gonna be a real monster when its done... :eek:
i know the regular 12plate (~190mm height) is rated for 20kw water-water.. so it's kinda oversized for our use actually.. i think it will work good as well baxz
Heh and then some, a 4-6 plate would do ;)
Water-Water ...:rolleyes:
look at water-oil and then imagin what refrigerant-refrigerant will be :down:
heat transfer between two liquids is much better than between one thats evaporating and one gas that is condensing...
I like the cart idea. :up:
Actually if you look back through Chilly1's oldest cascades, he used small 4-6 plate without any problems at all.
I don't think so....Quote:
Originally Posted by godmod
OK...Quote:
Originally Posted by Clemmaster
...would you mind to tell me why?
I think i said that a little bit too fast, but the heat transfer capacity water-water is up to 10 times higher than with refrigerant.
Very nice bazx, excellent idea on the portable chassis.
As this will eventually be the route i will go down (3 stage 507/1150/R?) I will be watching this thread like a hawk.
What kind of shut off valves are you going to use on the 2nd stage?
On my dual stage I used heat pump outdoor unit shut off valves which are designed for pretty much exactly what we use them for. Just not at the temps we do.
They work a treat, and they already have the vac port on the evap side suction.
i have the valves you are talking about here as the 2x 17000btu comps came out of a condensing unit
i was going to use one set for the evap mount dis mount
the valves i used on cascade 5 worked ok in a sealed box but i dont know if this will be the case at even lower temps i will need to have a good look around
You're not considering the working conditions at all saying what you said. What do you call heat transfert capacity? The fact that xxx W are transfered between the 2 fluids? In this case the capacity goes to ~infinity unless the heat-exchanger begins to melt because of temperature in both cases... In an interstage HX, all the heat load will be transfered from one refrigerant (condensation) to the other (evaporation) in every cases. The question is : with what deltaT between the two refrigerant?Quote:
Originally Posted by godmod
The heat transfert between two refrigerant that are changing phase and two liquid doesn't concern the same physical properties, you can't compare them as you do. In one case (refrigerant), all the heat load needed to be removed, for the system to work properly, will be, can't be otherwise. You want the CTD to be as low as possible. In the other case (liquid) you want both liquid to reach ~ the same temperature respectivly in inlet and outlet : in this case the heat from the hotter liquid is transfered to the colder one. You want the CTD at the end to be as low as possible, else it would mean that all the "heat difference" hasn't been transfered from one liquid to the other one.
You don't expect the same thing from both cases, that's why you can't compare them.
Now consider an evaporator and a waterblock : in this case you're expecting the same thing from both of them : the lowest CTD between the heatsource and the fluid.
In one case we will consider a stepper evap with a ~180w CPU in a basic prommy like phase unit (~ -40°C IHS temperature in these conditions) and a apogeeGT, 50L/h flowrate and a 29.2°C inlet temperature.
- With the evap I measured a 8K CTD between the IHS and the evap
- With the waterblock and these conditions , Rosco measured a 6.6CTD.
The two CTD aren't so different, are they? Now consider that in one case the massflow is 50kg/h (water) and in the other you've got a <10kg/h mass flow (R507c). Conclusion...
Now use a stepper evap in a waterloop with less than 10L/h inside and tell me what CTD you get? :rolleyes:
Conclusion? Nothing, you can't compare these two systems because you're not playing with the same working conditions at all.
Nice fab work on the stand Barie, Was there an issue with 4 or are you just parting it out? Anyway, i'm sure this will be another example of what happens when attention to detail and quality come together.
Hmm, thats right. But you can say that you can move more or less heat with water-water than with refrigerant-refrigerant if you include certain parameters.
And what is CTD? some C dT ? dT = temperature difference, what is C? Condensing...?! I have no idea.
Sorry, CTD = Constant Temperature Difference :p
If you say "move heat" without considering the physical effects around that would make a system be better than an other (deltaT, temperatures, pressures...) then you can find conditions in which the system you want to be better will be but theses conditions could be irrelevant.
Just to "move" heat, phase-changing is way better than a classic heat transport by a liquid. (enthalpy VS thermal capacity).
looks bazx, should go well at events ;)
Looks like a great idea. One concern though, as you add hardware to the cooling system, you're raising the center of gravity on the whole set-up. I would suggest to make the bottom "feet" the same area as the top table to increase stability.
I love this idea also !!
But a thought I had was a problem with shipping this around and a shipping container to put it in. With wheels on the bottom wouldn't be very hard to pack this and secure so it would not shift while being shipped ?
Water is a Refrigerant it boils in a vacuum,thats how we dehydrate systems.....For all you global warming guys start putting water away in jugs,when the atmosphere gets 250/300f out you'll be able to sell it as refrigerant,if you don't drink it First;) .Quote:
Originally Posted by godmod
Got some more of the chassis done over the weekend and today
Most of the mock-up is done now just need to put in some box section to fix the side panels too and I can send it off to be powder coated
The two 4 inch diameter logs are representing the oil separators
Also the de –super heaters will be mounted next to the first stage condenser
http://www.benchtec.co.uk/images/baz...p/CIMG0938.jpg
http://www.benchtec.co.uk/images/baz...p/CIMG0936.jpg
http://www.benchtec.co.uk/images/baz...p/CIMG0935.jpg
Looks good bazx, love your fab work
Very nice! And nice lathe!