Refrigeration - Evaporator vs. Holding Plate

[john61ct]

Just proposing benchmarks,

with purposefully extreme bookends to showcase systems' ability to handle them

Fill in whatever numbers you like.

If a unit is particularly energy efficient in the more realistic middle, at a reasonable price, but falls down at the unrealistic extreme,

that's likely the on I'd choose over a super-cool but thirsty or pricey one

[a64pilot]

I think you will find that since I believe they pretty much all use the same compressor that the better designed ones will be pretty close on efficiency.
The real huge variable on efficiency, is the one you can control. Insulation. I’d bet most of us would benefit far more by having real well insulated boxes than by having the most efficient system there is, seeing as how I’d bet most of us have stock ice boxes that we put conversion systems into. I know my 30yr old insulation sucks.

Gut feeling is you pick a system based on price, parts availability, service after the sale, ease of service and is there a real person you can call for help, which often rules out some of the big companies.
I don’t want to be routed to a call center in India

[john61ct]

I was specifically talking about settling the eutectic vs thin plate debate, and maybe also demonstrating TXV vs regular.

Pete shows radically greater efficiency for his eutectic setup, some members claiming that must be because his thin plate version is configured inefficiently?

If the different designs are to be tested against each other as fairly as possible, take extreme insulation out of the picture, provide a standard test box to focus on the other design & implementation factors.

[Typhoon]

Originally Posted by john61ct

I was specifically talking about settling the eutectic vs thin plate debate, and maybe also demonstrating TXV vs regular.

Pete shows radically greater efficiency for his eutectic setup, some members claiming that must be because his thin plate version is configured inefficiently?

If the different designs are to be tested against each other as fairly as possible, take extreme insulation out of the picture, provide a standard test box to focus on the other design & implementation factors.

What you are talking about is third party testing .

I’m in !

Tell me where to send a machine .

Regards John

www.coldeh.com

[wsmurdoch]

Originally Posted by ColdEh Marine

What you are talking about is third party testing .

I’m in !

Tell me where to send a machine .

Regards John

www.coldeh.com

That was my point in post 265 with Cruising World's 1995 head-to-head test.

Comparing a system to a unfairly chosen base system is just not useful. Pete's comparison does not reflect my situation. He does only a refrigerator. I want a freezer to, at the least, make ice and better still if it will keep meat frozen for a couple of months. I want all the tested systems to be optimized by their proponents. I want the boxes to have equal storage volume for food. I want the boxes full.

Pete has the thin plate evaporator system running flat out and cycling once an hour. The poor thing is operating with its evaporator temperature dropping to -24C while his holding plate need not go much below 0C. It is like asking two runners to travel a mile, one to walk the mile in an hour and the other to run 18 flat out 100 yd dashes resting 3 minutes between runs. Which do you think would be more tired?. I'd bet that simply slowing the compressor on the thin plate system to lengthen the cycles would greatly improve its efficiency by removing the energy costs of the repeated starts and by raising the evaporator temperature to lower the load on the compressor.

Drew Frye, Practical Sailor; do you hear this?

Bill

[Richard Kollmann]

Originally Posted by ColdEh Marine

What you are talking about is third party testing .

I’m in !

Tell me where to send a machine .

Regards John

www.coldeh.com

If you examine the tests form Pete and Rich both will give you the answer to what to believe about cycling eutectic and cycling standard evaporators.

If you want to believe Pete's test is a fair comparison then his eutectic plates over a standard evaporator reduces less than 1/3 of an amp per hour or 11 amp-hours per 24 hours. Check his figures these are not mine. Frigoboat keel cooler models with standard evaporators get the same performance by just eliminating the condenser fan.

If you already own an icebox conversion refrigeration unit with standard evaporator and you are seeing results like Rich's graphic test you should know better either he is referring to the danfoss BD 2 or BD2.5 or BD3 fixed speed compressors with too small of a standard evaporator or the thermostat's off differential time is too short. Correctly selected components for a conversion refrigeration system will control evaporator cycles to less than 50 compressor cycles per 24 hours. Cycling of 125 each day is not a realistic or fair example

Today with the breakthrough in variable speed Danfoss compressors like the BD35 and BD50 energy wasting extra cycling is controllable by matching condensing unit output to match evaporator capacity.

Remember, If it sounds to good to be true it may not be as true as it sounds.







i

[newhaul]

Originally Posted by Richard Kollmann

If you examine the tests form Pete and Rich both will give you the answer to what to believe about cycling eutectic and cycling standard evaporators.

If you want to believe Pete's test is a fair comparison then his eutectic plates over a standard evaporator reduces less than 1/3 of an amp per hour or 11 amp-hours per 24 hours. Check his figures these are not mine. Frigoboat keel cooler models with standard evaporators get the same performance by just eliminating the condenser fan.

If you already own an icebox conversion refrigeration unit with standard evaporator and you are seeing results like Rich's graphic test you should know better either he is referring to the danfoss BD 2 or BD2.5 or BD3 fixed speed compressors with too small of a standard evaporator or the thermostat's off differential time is too short. Correctly selected components for a conversion refrigeration system will control evaporator cycles to less than 50 compressor cycles per 24 hours. Cycling of 125 each day is not a realistic or fair example

Today with the breakthrough in variable speed Danfoss compressors like the BD35 and BD50 energy wasting extra cycling is controllable by matching condensing unit output to match evaporator capacity.

Remember, If it sounds to good to be true it may not be as true as it sounds.







i

1) Pete's systems are both made by him so there is no salesman bias .

2) Why the heck would I voluntarily put more holes in my vessel for refrigeration.

3)Why are you so negative about anything refrigeration that doesn't conform to your personal view?

[john61ct]

Originally Posted by ColdEh Marine

What you are talking about is third party testing .

I’m in !

Tell me where to send a machine .

Regards John

www.coldeh.com

I would be happy to put in the time - free labour - to transparently conduct such a test, as long as all out of pocket costs are covered, and I get to keep the unit of my choice when it's over.

Or someone else could do it, Practical Sailor or someone like Maine Sail would be ideal.

But to be honest, wrt all the members who contribute to these forums, I would trust each of their/your integrity to conduct the test yourself.

as long as full transparency is promised, all specs and HowTo instructions published, no proprietary "secret sauce" elements,

and everyone uses exactly the same box, contents and temperatures.

The goal would be anyone reading the build thread(s) could repeat the test conditions to verify results.

In fact multiple locations could test identical setups, would help ensure later repeatability.

[john61ct]

Originally Posted by newhaul

Why are you so negative about anything refrigeration that doesn't conform to your personal view?

I agree wrt his tone, but crotchety skeptics can be useful to help us keep vendors honest.

I personally do not doubt Pete's integrity, but am skeptical myself about extrapolating a general number for

Eutectic systems are always X% more efficient than thin plate

from his test results.

An open competitive multi-vendor testing protocol conducted in a public forum would help us determine the question with greater certainty.

[newhaul]

Originally Posted by john61ct

I agree wrt his tone, but crotchety skeptics can be useful to help us keep vendors honest.

I personally do not doubt Pete's integrity, but am skeptical myself about extrapolating a general number for

Eutectic systems are always X% more efficient than thin plate

from his test results.

An open competitive multi-vendor testing protocol conducted in a public forum would help us determine the question with greater certainty.

the thing is john he is a vendor

[Richard Kollmann]

Originally Posted by newhaul

1) Pete's systems are both made by him so there is no salesman bias .

2) Why the heck would I voluntarily put more holes in my vessel for refrigeration.

3)Why are you so negative about anything refrigeration that doesn't conform to your personal view?

newhaul, to answer your questions 1. Pete is vice president of sales engineering and has a good product so he has a right to be bias.

2. I agree with you putting any additional holes in a boat for a small refrigeration system.

3. I do not know of any boat refrigeration on the market today where there is not a good application for each design. We all form ope ions hopefully based on the facts we understand. If that makes my comments negative sometimes then you are correct.

[john61ct]

Originally Posted by newhaul

the thing is john he is a vendor

Ah. That was not clear calling himself retired.

Richard, links to your website, specific offerings?

[newhaul]

Originally Posted by john61ct

Ah. That was not clear calling himself retired.

Richard, links to your website, specific offerings?

I guess I forgot to say retired refrigeration vendor

[kmacdonald]

Originally Posted by wsmurdoch

For those of us in the United States, be aware that the title "engineer" in Australia is, unlike the case in the United States, not a protected title.

"The title 'engineer' is not protected in Australia, therefore anyone can claim to be an engineer and practice without the necessary competencies, understanding of standards, or in compliance with a code of ethics. This exposes our profession to poor quality engineering, a lack of public trust, and increased general risk – be it financial, safety or environmental."

https://www.engineersaustralia.org.a...tion-engineers

https://en.wikipedia.org/wiki/Regula...in_engineering

Bill

We have sanitation engineers in the US. They collect garbage. Some of Australians use the "engineer" term in a similar fashion and attract about the same respect.

[john61ct]

I trained and certified thousands of LAN and WAN "Network Engineers" - Novell, Microsoft, IBM Notes, Cisco in the 90's and oughts.

Some hadn't finished high school, just a couple hundred hours lab/class work then passing adaptive tests.

Most billed $100 - 200 an hour so did pretty well.