Originally Posted by missourisailor
Let for now assume that we have determined that a second holding plate would be of help.
Would there be any advantage to installing them as "shelves" as opposed to mounting them on the wall/s?
My thought is that it would help because all six sides would be able to absorb heat in the shelf configuration. On a wall mount only 5 sides would be exposed. With one of the larger square surfaces smack up against the wall and only able to soak up heat from the wall.
I would think that even if you mount it/them on stand-offs away from the wall, it would be better than right up against it (as mine is now)
What are your thoughts?
Absolutely there would be an advantage. The reality is that the "air gap" between the holding plate (or thin rolled evaporator) and the wall becomes filled with frost and ice since you really can't access it regularly to scrape it off with a spatula like you can the front and sides of the plate. Unlike a thin rolled evaporator, you simply are not going to punch a hole in the SS holding plate, so we recommend aggressive frost scraping frequently with a SS spatula to keep your frost from building up to over 1/4 thick and then eventually turning to ice.
So if you are able to mount your holding plate in a way that essentially makes the two large sizes available for more frequent de-icings and make that surface area available to more efficient heat transfer...bingo...you win.
But What do you win?
You will get lower box temps from the increased heat transfer, so that is a good thing of course.
Now for the money
question that you seem to be after:
Will you get a lower compressor
cycle on times OR a total decrease in daily power usage?
So then why go through the hassle of mounting the holding plate (all 25lbs of it) suspended in the box as a shelf if getting a lower daily power usage and better compressor
cycling is what you are after?
We seem to be dancing around the issue here so lets hit it head
If you already have the most energy efficient refrigeration
system, but are still using more power and have more compressor "on time" than you are happy with, how do you address that?
Let's make sure that the system you have is tuned correctly (Charge, TXV, and compressor Health).
2. Add insulation
to improve the R-value and shrink the box volume.
You can't beat the laws of Physics and if your Box volume and insulation R-value is letting in an amount of heat into the Box that requires the compressor (from any manufacturer or brand) to run continually to pull it out. Then the unit is simply undersized for that box and fine tune tweaking around the corners isn't going to fix that.
Adding the second holding plate if you have excess power available when the solar
is pumping out amps or when motoring can help reduce the overall power usage by means of storing energy in the places. It will also give you lower box temps...but what it won't do is make up for either a Box too large for the compressor to handle or for poor insulation. I don't want to sell someone a $900 holding plate for them to plumb in series to the one they already have and them not be happy with it because they were expecting things it was not going to be able to accomplish.