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View Full Version : Danfoss BD35 with a TXV/TEV ?







Typhoon
21-03-2016, 02:06 PM
Hello evryone.

This is my first post, been reading many and have learned a lot, Great forum.

I have a 12v BD35 based refrigeration set up that I have removed from my sailboat.

Its consists of A Danfoss BD35 compressor, a 32x 11 " evaporator plate made out out aluminium and has about 24 feet of passages in it . It has a 6 foot capillary tube and small fan driven condenser .

What I would like to do is change the set up to a system using a TXV with a large receiver drier and a much larger fan driven condenser, one with three cores measuring 9x10 " .

The problem is the Danfoss TXV TN2 with the 0X orifice is still much to big for my setup , Is there any way I could get a machine shop to make a smaller one ? Maybe a few different ones and try them until I get the system working properly?

This system would be much more stable and efficient in the hotter climates that I will be sailing in .

Thanks

frank
21-03-2016, 08:15 PM
I'm always interested to learn when people say ' it will be much more stable and efficient in hot weather' when asking for help on altering a system, without posting calculations or actual readings to back up the theory?

Can you post efficiency calculations/measurements before and as you see them after the alterations so that we can get a better understanding of what you are trying to achieve?

mikeref
22-03-2016, 08:09 AM
A BD35 compressor does not have the capacity to feed a TX valve.
Suction pressure higher than 10 PSI can easily overload your compressor motor. A slow feed through a specific length of Capillary tube with a precise internal diameter has to match your static evaporator.

The only alteration you can do is to change the revolutions of your DC Compressor. Say 2000 RPM to 2500 without significant 12 Volt current draw on your Battery.:cool:

Typhoon
22-03-2016, 02:10 PM
Thanks for the information every one , This company http://www.technauticsinc.com/ uses a TXV in there system , I would like to do the same thing but with a flat evaporator plate and not the holding plate . No Capillary tube ! they claim very stable and efficient refrigeration even in very warm climates with air cooling , My old capillary system would loss 1/3 of the frost on the plate in places that average 85 plus temperatures , even in my box which is 10 square feet and R50 insulation .

http://www.technauticsinc.com/

Regards

Brian_UK
22-03-2016, 04:11 PM
The It must be noted that they are using a holding plate whereas you want to use your regular evaporator. They are not the same system.

[edit] Also they are using a different compressor from your BD35, they have the GD30F which handles 50% more refrigerant than yours.

Read also here..... . .http://www.penguinfrigo.co.uk/shop/product/585/

Typhoon
22-03-2016, 07:14 PM
The It must be noted that they are using a holding plate whereas you want to use your regular evaporator. They are not the same system.

[edit] Also they are using a different compressor from your BD35, they have the GD30F which handles 50% more refrigerant than yours.

Read also here..... . .http://www.penguinfrigo.co.uk/shop/product/585/

Yes they do use a holding plate . They previously used a BD35 compressor but had reliability issue with them when they were starting to make them in China so the went to the GD30FDC Huayi compressor and stayed with that. Maybe I should get one of those .

There design is what I would like to do but with a flat plate evaporator


Regards

mikeref
23-03-2016, 08:50 AM
Yes they do use a holding plate . They previously used a BD35 compressor but had reliability issue with them when they were starting to make them in China so the went to the GD30FDC Huayi compressor and stayed with that. Maybe I should get one of those .

There design is what I would like to do but with a flat plate evaporator


Regards

Read the link you supplied. Charts in the "Why Choose" link do not provide a comparison using TX verses Capillary on the same playing field. These graphs are basically contradictory. Sure, a TX valve, albeit something custom made will force a 12 Volt compressor to use more amps on a stand alone Kit.

Heat transfer, using capillary or TX with current technology over a 24 hour period will consume similar amp/hours. Volumetric efficiency could give you faster cooling but not for free.