Feedback on my chiller project.

[floshey]

Hi guys :)

I need some feedback on my chiller drawing and some general questions.

http://frip.dk/yezzzz/chiller.JPG

So the real chiller will kinda look like this ( i know the fan can't breathe cause of the non existent space between the reservoir and fan, but i only noticed it when i was done drawing so i really didn't feel like remaking it)

The pipes i will be using has an inner diameter of 0.5cm, except for the evaporator which will be using 1cm diameter pipes. Also i will start off with 3.2m cap tube (0.031). Unless you can see other problems regarding my picture i just need some answers.

1)
The compressor is a Danfoss NLE15K (made for R600a), i have some R22, will i be able to use this gas instead of R600a, or do i need a lower pressured gas.
2)
I have a friend that will make an external temperature controller for me which will power on the compressor if the temp goes above 0c and shut down when the temp goes below -2c(temps are fictive)
Will this damage the compressor, turning it on/off all the time?

[KODE]

Hi floshey,

You are starting from scratch right? Do you considered direct die? It will give way better temps and save you the hassle of pump/insulation to the entire loop thingy, just a thought :)

Regards, KODE.

[floshey]

Originally posted by KODE
Hi floshey,

You are starting from scratch right? Do you considered direct die? It will give way better temps and save you the hassle of pump/insulation to the entire loop thingy, just a thought :)

Regards, KODE.

Yeah i will give better temps, but less heatcapacity, and i don't think insulation will be a big problem compared to putting the system together, so no i really can't see i advantage in direct die. And i really don't have the tools for making an evap, neither do i know anybody who ship them to EU.
I think that will be my 2nd project, but for now the chiller seems the easiet way to get some hands on experience ;)

[Twynn]

Originally posted by floshey

The compressor is a Danfoss NLE15K (made for R600a), i have some R22, will i be able to use this gas instead of R600a, or do i need a lower pressured gas.


I personally had some problems with R290 in a R600a compressor. And R290 has even a bit lower pressures than R22. The motor of a R600a compressor is quite weak. The first problem was that I couldn't start the compressor with this gas. Normally these compressors use a resistive start device (a PTC). By using a start capacitor I was able to let the compressor start. Next problem was that when I had a bigger load and some more R290 in the system (higher head pressures), at some point the motor was too weak to keep on running. I still want to try to fix this with a running cap, but I haven't done that yet :)

So yes, you might run into troubles with a high pressure gas. It's not sure, you just have to try :)



I have a friend that will make an external temperature controller for me which will power on the compressor if the temp goes above 0c and shut down when the temp goes below -2c(temps are fictive)
Will this damage the compressor, turning it on/off all the time?

These compressors are made to be switched on and of. Every normal fridge and freezer have a thermostat which switches the compressor. The only thing you have to take care of, is to wait some time before restarting the compressor. You need some waiting. So you have to see if the temperature difference of 2 degrees is enough to let the compressor rest for some time.

[floshey]

Okay, thanks for the info Twynn.

What about a R134a compressor, would they be more appropriate for the purpose?
The only models i can get my hands on are:
Danfoss r134a FR 11 G
Danfoss r134a FR 8.5G
Danfoss r134a NL 6 F
Danfoss r134a NL 7 F
Danfoss r134a NL 8 F
Danfoss r134a NL 9 F
Danfoss r134a NL 11 F
Danfoss r134a NLE 7 F
Danfoss r134a NLE 9 F
Danfoss r134a TL 2.5 F
Danfoss r134a TL 3 F
Danfoss r134a TL 4 F
Danfoss r134a TL 5 F
Danfoss r134a TLES 3 F
Danfoss r134a TLES 4 F
Danfoss r134a TLS 5 F
Danfoss r134a TLS 6 F
Danfoss r134a TLS 7 F
Danfoss r134a SC 18 F (Expensive)

So what i really need is a place with the right compressors that ships to EU.

[Blergo]

i know this is a bit off topic, but there is a guy in germany that makes direct die evaps and will ship wprld wide and his prices are very reasonable. i will be buying one a couple from him when i get round to makeign a direct die system. :)
owen

[floshey]

Originally posted by Blergo
i know this is a bit off topic, but there is a guy in germany that makes direct die evaps and will ship wprld wide and his prices are very reasonable. i will be buying one a couple from him when i get round to makeign a direct die system. :)
owen

Thanks for the info, i think i have seen his blocks before, i were a little sceptical about the design, but then again, im a phase change noob, the quality and finish on the blocks looked very nice though, so maybe i will buy a couple of them :)

PS. I really need a retailer that ships to EU, where i can get my compressor, filter etc.

(I rather buy them new, than finding them on the scrapyard, which i actually have visited quite a few times, without luck :()

[Twynn]

floshey: If you want temperatures of only around 0 degrees, probably all these compressors in your list will do. Just remember that the higher the displacement, the higher the capacity.

You can find all the capacities from these compressors on the danfoss site. (And remember, they are still made for R134a, not for R22.. Although I think you won't run into a lot of troubles as with the R600a systems).

It is just what you wish to make. A compressor with a large displacement will reach temperatures faster than the smaller versions.

If you want to go for the lowest possible temperature, a compressor with a larger displacement will reach lower temperatures with the same load than a smaller version :)


But this all is not only depending on the compressor. Also your metering device (captube or expansion valve) will determine the pulldown temperatures and end temperatures :)