Ammonia Fridges, read an interesting piece a while ago

[SidecarFlip]

Read an article concerning ammonia fridges and their relationship to ambient versus internal temperatures.

The article stated that the temperature differential is around 30 degrees internal versus external and it seems to hold water in my testing.

Been running my Dometic on shore power in the side yard (empty). I have adequate airflow over the upper condenser with the correct baffles and 2 120mm muffin fans pulling the air through the backside cavity from the lower intake out through the upper vent and 2 additional muffin fans inside the fridge circulating cold air inside. The fridge is well insulated, I added almost a full roll of unfaced R11 insulation around the entire fridge, between the fridge body and the outer cabinet so I'm as 'efficient' as I can get.

I have a recording remote thermometer in the fridge with the readout outside and I've watched for about a week now and the interior temp averages about 30 degrees colder than ambient, more at night, closer to 50 dergrees differential than during the day when it drops back to around 30

The article I read seems to be correct at around 30 degrees temperature differential.

I think this winter, I'll be pulling the Dometic ammonia fridge and installing another Dometic C series Danfoss Compressor unit in it's place. I have a portable Dometic Cool box I carry in the truck and it has no issue holding whatever temperature I set it at from 30 degrees on up in the fridge section to minus 15 in the freezer section.

[chag67]

dougrainer wrote:

chag67 wrote:

dougrainer wrote:

chag67 wrote:
My Norcold 2118S was working flawlessly. Then 2 months ago, the temps climbed to 60 in the fridge and 28 in the freezer. I set up a visit with a NORCOLD CERTIFIED technician recommended by NORCOLD. The technician stated it was a bad cooling unit. Norcold has since recommended that the technician come back out for minor things before they will send their own technician a cooling unit to install. Each visit is $175 out of my own pocket due to the mobile tech charge. The reason the mobile charge is that high is they are the closest to my at 2 1/2 hours away. Norcold units may be good but their customer service UNDER WARRANTY sucks. I have decided to scrap their crappy fridge and change to a residential. Norcold can go to #$%^!!!

Note that my RV and fridge are under warranty and are only 6 months old.

While you have a Warranty, YOU must make arrangements to get that Norcold to a Service Center. The fact YOU hired a Mobile Tech is NOT Norcold's fault. YOU chose to live 2 1/2 hours away. That is NOT Norcold's fault. These are MOBILE RV's and you need to get the RV into the Service Center for the best result and repair. Doug

My problem is not with the mobile fee. My problem is with Norcold ignoring THEIR OWN technician's recommendation as to what needs to be fixed. I had a non-Norcold mobile tech tell me it is a bad cooling unit. I had a NORCOLD mobile tech tell me it is a bad cooling unit. NORCOLD will not send their own NORCOLD mobile technician a new cooling unit to replace the bad cooling unit in my 6 month old Norcold fridge. NORCOLD customer service and warranty service sucks.

I don't know where you think Norcold has Technicians. They do NOT. They have Service Centers and independent Technicians that are AUTHORIZED to do warranty repairs. As in all things in life, there are competent and incompetent Repair people. IF a Authorized Norcold AGENT calls Norcold with the check out facts and it warrants a NEW Cooling Unit, they will replace the CU or send a complete NEW Refer. I have delt with both Norcold and Dometic for 38 years and still do. I have no problem getting what I need when the facts are presented.
Doug

I am glad that you have not had any issues with Norcold in your experiences.

Mine have been less than stellar. It is a non-issue now. I have a residential fridge now. My opinion of Norcold has been formed based upon my personal experience dealing directly with Norcold on the phone and their authorized technicians. I will never have a Norcold fridge in any of my RVs.

[dougrainer]

chag67 wrote:

dougrainer wrote:

chag67 wrote:
My Norcold 2118S was working flawlessly. Then 2 months ago, the temps climbed to 60 in the fridge and 28 in the freezer. I set up a visit with a NORCOLD CERTIFIED technician recommended by NORCOLD. The technician stated it was a bad cooling unit. Norcold has since recommended that the technician come back out for minor things before they will send their own technician a cooling unit to install. Each visit is $175 out of my own pocket due to the mobile tech charge. The reason the mobile charge is that high is they are the closest to my at 2 1/2 hours away. Norcold units may be good but their customer service UNDER WARRANTY sucks. I have decided to scrap their crappy fridge and change to a residential. Norcold can go to #$%^!!!

Note that my RV and fridge are under warranty and are only 6 months old.

While you have a Warranty, YOU must make arrangements to get that Norcold to a Service Center. The fact YOU hired a Mobile Tech is NOT Norcold's fault. YOU chose to live 2 1/2 hours away. That is NOT Norcold's fault. These are MOBILE RV's and you need to get the RV into the Service Center for the best result and repair. Doug

My problem is not with the mobile fee. My problem is with Norcold ignoring THEIR OWN technician's recommendation as to what needs to be fixed. I had a non-Norcold mobile tech tell me it is a bad cooling unit. I had a NORCOLD mobile tech tell me it is a bad cooling unit. NORCOLD will not send their own NORCOLD mobile technician a new cooling unit to replace the bad cooling unit in my 6 month old Norcold fridge. NORCOLD customer service and warranty service sucks.

I don't know where you think Norcold has Technicians. They do NOT. They have Service Centers and independent Technicians that are AUTHORIZED to do warranty repairs. As in all things in life, there are competent and incompetent Repair people. IF a Authorized Norcold AGENT calls Norcold with the check out facts and it warrants a NEW Cooling Unit, they will replace the CU or send a complete NEW Refer. I have delt with both Norcold and Dometic for 38 years and still do. I have no problem getting what I need when the facts are presented.
Doug

[mchero]

I wish I had just one dollar for every misdiagnosed Norcold or Dometic fridge!

[chag67]

dougrainer wrote:

chag67 wrote:
My Norcold 2118S was working flawlessly. Then 2 months ago, the temps climbed to 60 in the fridge and 28 in the freezer. I set up a visit with a NORCOLD CERTIFIED technician recommended by NORCOLD. The technician stated it was a bad cooling unit. Norcold has since recommended that the technician come back out for minor things before they will send their own technician a cooling unit to install. Each visit is $175 out of my own pocket due to the mobile tech charge. The reason the mobile charge is that high is they are the closest to my at 2 1/2 hours away. Norcold units may be good but their customer service UNDER WARRANTY sucks. I have decided to scrap their crappy fridge and change to a residential. Norcold can go to #$%^!!!

Note that my RV and fridge are under warranty and are only 6 months old.

While you have a Warranty, YOU must make arrangements to get that Norcold to a Service Center. The fact YOU hired a Mobile Tech is NOT Norcold's fault. YOU chose to live 2 1/2 hours away. That is NOT Norcold's fault. These are MOBILE RV's and you need to get the RV into the Service Center for the best result and repair. Doug

My problem is not with the mobile fee. My problem is with Norcold ignoring THEIR OWN technician's recommendation as to what needs to be fixed. I had a non-Norcold mobile tech tell me it is a bad cooling unit. I had a NORCOLD mobile tech tell me it is a bad cooling unit. NORCOLD will not send their own NORCOLD mobile technician a new cooling unit to replace the bad cooling unit in my 6 month old Norcold fridge. NORCOLD customer service and warranty service sucks.

[SidecarFlip]

Math was never one of my strong points. I used to sit in the front row so I could gaze at Ms. Pendergast's long legs....

[pianotuna]

Ambient is 100.4 f (38 c) at 2:25 local time at 51.911669, -106.821398

Fridge is 37 f (2.78 c)

My delta T is 63f (35 c)

I have a mask with twin computer fans at the top of the "chimney" which are controlled by a thermostat. I do have a small interior fan to circulate the air in the fridge. (a Dometic).

[SidecarFlip]

Always had the fans in mine. 2 in the backside 2 inside the fridge itself.

[doxiemom11]

Our Norcold was suddenly having a problem staying cool in 100+ sunny heat. Discovered the cooling fans were not working. DH installed a fan in lower outside compartment blowing up.( Hard to get to the factory ones) We were able to put awning out ( wind calmed down) and it was back to keep the frig around 34-35 degrees. So - the frig cooling capacity can be affected by things other than the cooling unit.

[SidecarFlip]

mike-s wrote:

SidecarFlip wrote:
Big thing for me is the quick cool down, much more consistent temperature control and no hazardous chemicals inside (compressor fridges use enviromentally safe R134.

Hardly environmentally friendly - see here. It has over 1000 times the "global warming potential" of CO2. Better than the old R-12, though.

Ammonia and hydrogen, on the other hand, have very little environmental impact. Concentrated ammonia can be corrosive and toxic, but that's about it unless you dump it on ground/water. A slow leak from an RV fridge isn't a threat. The vast majority of ammonia is made for use as fertilizer.

SidecarFlip wrote:
A typical Secop/Danfoss compressor pulls less than 5 amps at 100% duty cycle and most time is pulling less than 2 amps. An ammonia fridge with auxillary cooling fans is approaching that and it's basically all the time.

Huh? My Dometic RM2652 draws about 0.7 A when running on propane, and I haven't bothered to disconnect the anti-condensation heater between the fridge and freezer. <1 A with the interior fans on. And that's when it's drawing power to keep the gas valve open.

In as much as I farm, I use granulated 46 Urea and anhydrous all the time so I already know that.

My fridge without any fans might pull 1/10th of an amp but I have 2 in the back cavity up top to pull the air through which is a necessity for me, that is 2 amps and two more inside to circulate the cold air, (another amp or so). A Secop unit pulls around 5 on max duty cycle but substantially less most of the time.

Far as the chemicals in the ammonia fridge, so long as they stay contained it's a non issue just like the 134. It's when they leak, they pose a hazard and can be a flammable mixture as evidenced by the many RV fires from them.

Other nice thing about a Secop unit is it don't have to be level to operate efficiently. No thermo siphon principle to consider. A Danfoss/Secop unit can operate at up to 30 degrees out of level. An ammonia unit cannot.

[SidecarFlip]

red31 wrote:
SidecarFlip, got a compact fridge with out a freezer?

It's a Dometic compact with a small freezer. Americana I think.

[mike-s]

SidecarFlip wrote:
Big thing for me is the quick cool down, much more consistent temperature control and no hazardous chemicals inside (compressor fridges use enviromentally safe R134.

Hardly environmentally friendly - see here. It has over 1000 times the "global warming potential" of CO2. Better than the old R-12, though.

Ammonia and hydrogen, on the other hand, have very little environmental impact. Concentrated ammonia can be corrosive and toxic, but that's about it unless you dump it on ground/water. A slow leak from an RV fridge isn't a threat. The vast majority of ammonia is made for use as fertilizer.

SidecarFlip wrote:
A typical Secop/Danfoss compressor pulls less than 5 amps at 100% duty cycle and most time is pulling less than 2 amps. An ammonia fridge with auxillary cooling fans is approaching that and it's basically all the time.

Huh? My Dometic RM2652 draws about 0.7 A when running on propane, and I haven't bothered to disconnect the anti-condensation heater between the fridge and freezer. <1 A with the interior fans on. And that's when it's drawing power to keep the gas valve open.

[red31]

SidecarFlip, got a compact fridge with out a freezer?

[valhalla360]

Yes, if you get into extreme conditions, it's possible to overwhelm the fridges ability to stay cold.

But properly installed and operating, no issues holding a steady cold temp even under very warm conditions. There isn't a magic 30C delta.

[SidecarFlip]

dougrainer wrote:

MDKMDK wrote:

dougrainer wrote:
Sorry, but there is No Relationship between external temps and interior refer temps. THAT SAID. If you park a RV in 100 degree heat and have NO AC cooling the inside and have the refer ON, odds are it will not cool to spec. Doug

? So if the air temperature around the refer (ambient) is extremely high, the interior will probably be higher, too? Sounds like an "external/interior relationship" to me.
Just sayin' :B

I guess I have to type slower for some people to understand. IF you put a refer in a HOT inside interior, then that can affect the cooling temp in the refer. Like people that would have their RV parked in a hot storage lot with minimal 120 and cannot run their roof AC. THAT is not real world using the RV and refer. Nobody is going to live in an RV that is 110 plus INSIDE because they have no roof AC. Doug

I DO NOT have ac on my RV at all. I don't need it for one and because of where I camp at 95% of the time, it's unnecessary. We don't inhabit the camper except at night. To me, camping isn't about sitting in a RV watching the boob tube or playing on a computer. We are outside unless we are sleeping and that is at night.

I read your comment about your freezers at home with interest. I have 2 chest freezers in my uninsulated garage. One contains game meat, the other frozen grocery store items and garden vegetables and neither have any issue holding a sub zero interior temperature no matter how hot in is in the garage (an be over 100 (f) at times and as cold as 0 (f) in the winter. Cabinet temps are always consistent and below 0, no matter what season it is.