BD35 compressor not making frost on plate .

[SV THIRD DAY]

Hey looking good.
The final tweaks of the TXV can be made in the box but your amps, and pressures look right. Once in the box, tweak the TXV to get 2-3psi on the low side and you will be perfect. How does the sight glass look?

[ColdEH]

Hey Rich ,

I have two sight glasses one just before the TXV and one on the reciever dryer . The one at the dryer was showing no bubbles but the one at the TXV had a little bubble so I gave it one more squirt of refrigerant and it disappeared . It stayed clear at all compressor speeds , you can see the bulb in the ice in the photo , won't need that once I get it in the box . Now I have a full set of Hvac tools . Should come in handy down south 🤓

Regards John


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[SV THIRD DAY]

Great work John...
Sounds like you are perfectly charged!
A cruiser can NEVER have too many tools...and you never know when your dock buddy may want to trade a few beers for you to vacuum down his system!!!

[ColdEH]

Hey Rich .

I got the system installed yesterday , just roughed in so far . Turned it on a 5pm at low speed in an empty 7.7 cubic foot box . System started to make cold right away and froze the plate quickly . I placed two water bottles at the bottom of the box, this morning at 6am they were ice . Temperature in the boat was around 78 . I have not checked my pressures yet or tweaked the TXV I will do that tonight . But I am surprised the system brought down the box that fast on low speed , Very pleased !

I will start a new thread on my build including the box and insulation once I get it completed with shelving and thermostat installed . Will also give daily amp hour usage measurements

Regards

[SV THIRD DAY]

Great news....
Cool Beer and Ice Cream on the boat turns camping into Cruising...ha ha ah

[ColdEH]

This system is working great .

I have had it in the box and running for the past three days with all the shelving and half full of food in this hot weather , Boat is closed up during the day and it gets warm inside , around 85 degrees a little warmer then out side . I tweaked the TXV for 2 psi of suction at 35 degress box temperature . I keep it between 2 and 4 degrees Celsius all the time .

So far my amp hour usage averages out to 27ah for 24 hours for this 7.7 cubic foot top loading box , so needless to say I am very happy.

When I get time i will start a thread with all the build photos

Now to do the same to the freezer.

Regards

[ErikFinn]

So do I understand correct that this tweaked system makes more BTUs than the original one in ideal conditions? If so, why? Because of the larger condenser? Because of the receiver dryer? Or because of the TXV?
I know its early to say but could this system be more reliable than say a standard AB BD 35 system off the shelf?
How about the budget? How much did you spend on the new parts?
CCheers

[ColdEH]

Originally Posted by ErikFinn

So do I understand correct that this tweaked system makes more BTUs than the original one in ideal conditions? If so, why? Because of the larger condenser? Because of the receiver dryer? Or because of the TXV?
I know its early to say but could this system be more reliable than say a standard AB BD 35 system off the shelf?
How about the budget? How much did you spend on the new parts?
CCheers

To your questions ,
YES YES AND YES .
this is a little article I found describing some of the advantages.

Thermal Expansion Valve - Thermal Edge

The main reason they are not used in small marine refrigeration systems is PRICE.

I think I spent about a thousand dollars putting my system together from cobbled up parts on e bay and Rparts , thats not including the tools.
But i am very happy with my system and am about to build another one for my freezer.

Technautics Cool Blue system uses a TXV in there system. It is three times the price of a comparable capillary system but well worth the money .

They use a holding plate which works just fine , but I wanted tighter control over box swing temperatures so i used a flatbond evaporator plate . Nobody builds a system like that, so i built one .

As for reliability a capillary system is very sensitive to dirt or moisture . Because you are not limited to the amount of refrigerant you can put in a TXV system, you can install a very large receiver dryer , which takes out much more moisture and has a very large filter area to stop any particles from jamming in the capillary tube which is a huge problem . Also you can have a huge condenser for just the same reason and this is another thing that just makes it all work more efficiently. I am using a 10 inch low rpm fan on my condenser and you can not hear it run. I am getting a great amount of subcooling through it.

Regards

[ColdEH]

Just to add . Capillary systems are designed to work in a controlled environment such as a house were the temperature is a constant, and they work fine . We have boats, we like to move our boats. Temperature swings are massive inside a boat . We all need a TXV system !!!!

Regards

[ColdEH]

Almost a year in and the whole thing leaked out and blew up !!
Just kidding , still working great . It's actually a little boring , I like to tinker and there has been no reason to touch the system . Got bored of counting the amp hrs as well but now since the cold weather is here I took a look and I am using well under 20 amphrs a day . Temperature outside is 0 c and 22 C inside .

Regards

[ErikFinn]

Originally Posted by typhoon

Almost a year in and the whole thing leaked out and blew up !

My heart missed a beat when I read that..

[ColdEH]

Thanks Eric , sorry about that lol [emoji23].
No all is working well , I'm just about to install the freezer condensing unit , just finishing up a bunch of tests on it and in it goes, never to be seen again .
Regards

[botanybay]

Originally Posted by typhoon

Finally got it working . I evacuated the system and turned around the TXV .
Could not balance the system , this valve has no superheat adjustment but it was designed for small systems so I thought impulse give it a go , no luck . It was to big , just flooded the system and did not make enough of a pressure drop to to get going , I even put the bulb in ice, but still no luck . Evac the system again and put on the Danfoss tn2 with the OX orifice . Finally. ! Got it working . Had to adjust the superheat a bit , but it did the job . Pressures are just under 100 psi high side and 5 psi on the low side , and the plate is out of the box and in the open air , drawing just 2.4 amps at 2000rpm . I'm sure I will have to make a few adjustments when I get it in the box . I am getting loads of sub cooling with this condenser and a slow running 10 inch fan . I'm very happy with the setup , now to build another one for the freezer .

RegardsAttachment 125085Attachment 125086


Sent from my iPhone using Cruisers Sailing Forum

I too have been having fun with my old 1/2 hp holding plate system as a learning project. It is R12 so I got the right license, the right tools (gauges, vacuum pump, recovery pump, recovery cylinder) and have been learning quite a bit over the last few years.

The one question I have about using your evaporator is how did you bypass the embedded capillary tube? Was it external on this one and you cut it off or something else?

Also, how did you braze to the aluminum or was the remaining stub copper on the inlet side.

Looks like a nice solution all around!

Great work

[Typhoon]

The novakool plate I used had the captube outside the plate inside the suction tube . So just cut it off .

The aluminium joints had the crimped copper ends , I just soldered to them .
This system has been running since I installed it . No trouble and incredibly efficient. Not as good as my copper plates and no where near as tough .

Regards John
www.coldeh.com

[ccannan]

Originally Posted by ColdEH

Still fiddling with this thing , keeping my mind busy for sure !

I found an even smaller TXV /TEV , a Honeywell TLK with the smallest orifice of .3 . The TN2 danfoss was a .68 Kw valve with the OX orifice , the Honeywell TLK is .36 Kw . I think this will make it easer to balance the system . It is also available as a MOP valve .

Cant wait to put the pieces together and see if it will work

Regards

Which orifice did you end up using? OO, OX, Honeywell TLK, or MOP valve?