First Single Stage Build

blindfitter · 10-19-2009, 10:30 AM

Hi Guys,

In need of some guidance on my first Single stage build.

Luve 194 Condenser 1.94kw
Sanyo 9.6 Rotary Compressor
Copper spun filter
2200mm 0.031” cap tube
Chilly clone Evap.
R507 refrigerant A-gas

A couple of pics:

My Heat loader
250watt cartridge (RS)
400watt dimmer switch (B&Q)

A pic:

After numerous builds, with differing cap tube sizes and lengths, and many hours reading threads I’m at this stage.

Can you tell from the above findings, whether I still need to reduce the cap tube length? Or have I over/ under charged it?
I have the looked at the PT table for 507, and would like guidance please.

Also the condenser may be too large for this unit.

All advice is truly welcome.

EvoCarlos · 10-19-2009, 10:44 AM

shouldnt that be a cascade that i built you ?? that worked lol

oh but it seams the cap tube is to long its set up perfect for no load but i think you need to shorten the cap tube till you are getting -40 to the evap i dont know
i may be wrong

cant beleave you destroied the cascade i spent my spair time building (not happy)
sorry is just the way i feel about it^^

blindfitter · 10-19-2009, 11:04 AM

Hi Carl,

Cap tube is already down to 2200mm, and the recommended size I read on here is start at 3100mm so I thought that something else may be an issue.

EvoCarlos · 10-19-2009, 11:27 AM

Quote:

Originally Posted by blindfitter

Hi Carl,

Cap tube is already down to 2200mm, and the recommended size I read on here is start at 3100mm so I thought that something else may be an issue.

strange scootas unit uses the exsact same comp with a 1m suctin line and and condencer of simmler size and that uses 2.4m of 0.031

i take it the bit of 1/4 is just for support of the discharge line

is your sight glass full under 180w load ?

chilly1 · 10-19-2009, 11:48 AM

Two things,, Reducing the refrigerant inthe system will lower the capacity and the temperature, lengenthinging the capillary tube and keeping the same volume of charge will appear to do the same. You need to balance the system I use 60 inches of 0.028 for a 12 cc displacement compressor with 3600 RPM or 44 cuin/hr max and is dependant on pressures and temperatures of everything in the system. Simpler find the optimum by experemential means, recover your gas install a high side valve so you can pump the system charge into the condenser install enough access points so you can evacuate the portions of the system open to atmosphere...

chilly1 · 10-19-2009, 11:54 AM

Quote:

Originally Posted by EvoCarlos

strange scootas unit uses the exsact same comp with a 1m suctin line and and condencer of simmler size and that uses 2.4m of 0.031

i take it the bit of 1/4 is just for support of the discharge line

is your sight glass full under 180w load ?

Never use a sight glass in a capillary tube system, you do not want a full liquid line, capillary tube systems utilize the cold suction line to provide cooling to condense the final portions of the refrigerant. The use of a sight glass actually causes a reduction in capacity in your system, it acts as a small reciever, same reason for a bullett dryer too large a drier in a capillary system acts as a reciever, the reason the capacity is less is that the HX (cap tube suctionline interface) removes the specific heat remaining the the gas portion of the two phase refrigerant in the cap tube as it travels to the evaporator.
it seems that the teaching of new builders here has lapsed as I have been gone...

chilly1 · 10-19-2009, 12:01 PM

Remove the Sight glass recharge to 4 PSI Suction Test at 180 watts for ten min, monitor temp every 1 min write it down, remove charge to 2 psi suction repeat, when charging let it run for 10 min under load then top charge then get your readings, remove as many variabls as you can, keep temp readings to compare so that only the charge is changed. do it at 0. Change the capillary to one 20cm longer and repeat do the same with a 20 mm shorter captube, write all your findings down and think on what you have, this should reveal what you need to do to lower the temperature and maximize capacity...

blindfitter · 10-19-2009, 12:07 PM

Quote:

Originally Posted by EvoCarlos

i take it the bit of 1/4 is just for support of the discharge line

is your sight glass full under 180w load ?

yes it was, but I have removed it along with the sight glass, as I read previously the the sight glass acts like a reciever. See pics near end of thread.

Have built a reclaim unit already, but will strip down and add more acces points, as you rightly say it will certainly make it easier to get the gas out.

Thanks for comments and advice keep them comming

blindfitter · 10-19-2009, 12:27 PM

Quote:

Originally Posted by chilly1

Remove the Sight glass recharge to 4 PSI Suction Test at 180 watts for ten min, monitor temp every 1 min write it down, remove charge to 2 psi suction repeat, when charging let it run for 10 min under load then top charge then get your readings, remove as many variabls as you can, keep temp readings to compare so that only the charge is changed. do it at 0. Change the capillary to one 20cm longer and repeat do the same with a 20 mm shorter captube, write all your findings down and think on what you have, this should reveal what you need to do to lower the temperature and maximize capacity...

That will keep me busy for a while, will be back with results later this week

sdumper · 10-19-2009, 06:10 PM

Quote:

Originally Posted by chilly1

recharge to 4 PSI Suction Test at 180 watts for ten min, monitor temp every 1 min write it down, remove charge to 2 psi suction repeat, when charging let it run for 10 min under load then top charge then get your readings, remove as many variabls as you can, keep temp readings to compare so that only the charge is changed. do it at 0. Change the capillary to one 20cm longer and repeat do the same with a 20 mm shorter captube, write all your findings down and think on what you have, this should reveal what you need to do to lower the temperature and maximize capacity...

Good insight and post!!!

ViViD · 10-19-2009, 10:31 PM

That's Great Man For Single Stage :O

Can't Wait For Next Week

blindfitter · 11-10-2009, 10:04 AM

Been awhile, but have been busy, cutting, changing captubes, I think I learnt some aspects of the influence the cap tube has. Also changed some pipe work, some for better and some I need to change Lp take off freezes the guage.

Anyway a few pics then the test data. Managed a 10minute plus at 270watt and held at -22C so it looks like were now going in the right direction

Captube .09mm length approx 3.5mt
Static 7barg, Ambient 9C

Started up and ran idle for 5minutes:
SH= -32.5C, temp measured 6” from bulb (not sure if this is sh but people measure this).
Evap = -40.5C
Pipe = -42.5C (this the suction pipe 20mm from evap)
HP = 9 barg
LP = .2barg

Loaded heat loader to 180watt

Temps took every minute for ten minutes: temps are negative unless preceded with a +

1 =31.0
2 = 29.8
3 = 30.8 HP 10barg, LP .4barg
4 = 30.6
5 = 31.3
6 = 30.4 ( SH= 31.2c)
7 = 27.7 HP 10barg LP .6barg
8 = 26.8
9 = 26.4
10 = 26.4

End of test readings: HP=10bg, LP=.6bg,SH=29.2C, Pipe=33.3C
Bulb completely frosted.

Turned up load to 235watt:
1 =25.1
2 = 24.7
3 = 24.3
4 = 24.2 HP 11barg, LP .7barg
5 = 23.9
6 = 23.9
7 = 24.0
8 = 24.0
9 = 23.9
10 = 24.0

End of test readings: HP=11barg, LP=.8barg, SH=26.1C, Pipe =31.6C
Bulb still completely frosted.

Having got through this test decided to go full load 275Watts

1 = 23.6
2 = 22.7
3 = 22.5
4 = 22.8
5 = 22.4
6 = 22.8
7 = 22.5
8 = 22.5
9 = 22.5
10 = 22.5

End of test readings: HP=11barg, LP=.8barg, SH=25.1C, Pipe =31.4C

Bulb still completely frosted.
Some questions:
The HP seems low compared to pics seen here, I will add more captube to give more vacuum then add more gas, ? more HP.

Superheat, I understand how it works with steam! But not with refrigeration, could some explain with the figures above if possible, I read that superheat needs to be 4 – 12c how/ why and where.

Await your comments, and thanks for the help.