Air vs water or both for cooling refrigerant

[skipgundlach]

Originally Posted by ka4wja

Skip,
While this describes things well....I'm left wondering if your earlier question was rhetorical? (if so, my apologies for bothering your with direct answers)....





Earlier you asked do we have any suggestions to establish why it isn't working properly....I answered you directly here in post #16, but we never heard if these answers were useful...
http://www.cruisersforum.com/forums/...ml#post1614347

Please advise if these direct answers (as well as real world info, from someone just a few miles from you), were helpful....



Fair winds..

John
s/v Annie Laurie

Hi, John,

My apologies. I thought I'd answered your questions, and added commentary, inline. Perhaps it went missing (my internet here is abominable).

To recap, yes, I've been in extensive correspondence with Richard Kollman. However, my recent mail, and one of 7-2-14 have gone unanswered; Gord May reflected that he's been inactive of late in another thread, so perhaps he's died, finally. I have read his site, and have read, his book (I own it), and have met him personally (not for service work but in a SSCA GAM). Earlier last year, he lamented that while he'd seen me in Lake Sylvia, he'd not gotten a chance to visit (presumably by dinghy, as has our email) but found us gone before he made it. At that time, we were still fighting with our Frigoboat system.

I've heard from many, and looking at other threads, even more, that air cooling is superior and effective and sufficient even in desert 100+F scenarios. My dissatisfaction with having to have utilized the water option on my SeaFrost replacement was instant; my difficulties with my cooling water packing up don't lessen that dissatisfaction, but, at least so far, it appears to be the only way we'll get cycling on our system (vs running full time; it's bad enough as it is).

We know Mack Sails folks well enough, having done business with them for the last 6 or so years, and would not hesitate to use them for other stuff.

However, my system is still under warranty; despite the month of tweaking and messing and defective-part-replacement plus adding water cooling that Hansen Marine (the outfit referreed to me by Frigoboat) did, it's still not working.

If all the folks - you included, I think, but CRS rampant in this almost-70 OF (old fart), so ICBW - who remonstrate with details of how superior their air-only systems are can be believed, I should not need the water option in mine, either.

I'm in no position to judge, our presence in Vero Beach in the boat being limited to relatively recently, but folks here are apparently misled/misobserving the condition of the water however far north it is of Stuart, as the complaints are consistent with it being worse than any time in recent memory for those who live and work here.

As to any of the referrals you've provided, including Mack and Beard, thank you for the glowing testimonials. It's much better to have those who have actually used a provider's report than mere hearsay. I may get to that point; I went to Stuart to enable the diesel mechanic to do our injector pump rebuild, so taking the boat there for refrigeration resolution isn't out of the question. I'd much rather the installing company resolve it, however, as I'm already broke.

As to other water cooled mediums, I commented only on the apparent efficiency of them, witnessing the (I know of none, so I qualify the comment) lack of air-cooled AC systems aboard the typical boats. I don't like my having to use water, for all the obvious reasons as well as the absolute misery of dealing with packed-in feed lines (at least as ours is installed - if this continues, I'll have to consider moving the water intake/source/filter/whatever to make servicing it frequently manageable) in our system.

Did I address your concerns?

Thanks for your help. We can't WAIT to get out of here; perhaps we'll share an anchorage in your neighborhood sometime before I die or shoot myself.

L8R

Skip

[sailorchic34]

Ok, One last suggestion. As an experiment, take the four gallons of water bottles out of the freezer and see what your cycle times are then.

That "flywheel" will use an extra 15-ish minutes of cooling on medium for every run(on/off) cycle, assuming a 3 degree on off delta . While at first glance it looks like it will help, if you do the calc's, its adds to the energy load.

Ice storage systems are used in commercial systems, but only as a means of peak demand shaving. The cost to make the ice in thermal storage at fixed energy costs is not viable.

It does sound like your box is well insulated.

Please don't use chlorine tablets all the time, as the chlorine will pit and corrode copper tube and you really don't want that.

[onestepcsy37]

Cheap experiment. Buy a 4x8 sheet of insulation and cut it up so that you can insert the cut pieces into the bottom of the existing box. In effect you are raising the floor and decreasing the box size. Reduce the cubic foot capacity by half. Then try running the system. I did this to my box and it cut run time by nearly half. If things improve then maybe box size is the problem.

[Dulcesuenos]

We have a spillover system 4cu ft freezer into a 4 cu ft fridge, both plates in the freezer section and a air cooled seafrost bd80xp compressor. Cleave wasnt 100% it was enough for our wants but it works great even when its 90 out. Power consumption is decent. Our box is heavily insulated. Freezer stays at 15 degrees fridge around 35. Has fan assisted heat duct to remove heat from compressor. Overnight our power draw from it is only about 8 amps. Sounds like you need. Better air circulation crossover vents larger or better insulation.

Sent from my LG-LS980 using Cruisers Sailing Forum mobile app

[MarkSF]

"with fan (closed cabinet, heat output ducted outside)"

I hope the cabinet isn't truly closed - is there a way for air to be drawn in, so that it can be blown outside by the fan? If there isn't, that would explain a lot.

[skipgundlach]

Originally Posted by Dulcesuenos

We have a spillover system 4cu ft freezer into a 4 cu ft fridge, both plates in the freezer section and a air cooled seafrost bd80xp compressor. Cleave wasnt 100% it was enough for our wants but it works great even when its 90 out. Power consumption is decent. Our box is heavily insulated. Freezer stays at 15 degrees fridge around 35. Has fan assisted heat duct to remove heat from compressor. Overnight our power draw from it is only about 8 amps. Sounds like you need. Better air circulation crossover vents larger or better insulation.

Sent from my LG-LS980 using Cruisers Sailing Forum mobile app

I'm not sure to what you refer regarding crossover vents. Our spillover is so effective that, in the past, when we had a working freezer, we had to stuff the top with cloth (allowed some but not much air through) to keep our stuff in the reefer from freezing (because convection alone was too effective)...

Originally Posted by MarkSF

"with fan (closed cabinet, heat output ducted outside)"

I hope the cabinet isn't truly closed - is there a way for air to be drawn in, so that it can be blown outside by the fan? If there isn't, that would explain a lot.

The cabinet in a Sea Frost is the one with the compressor and (if it has water option) water and air cooling elements inside. The large side is the fins for the air condenser. The intake side for plumbing and electrical has a 4" fan which you can either duct air to, or from, the cooling. Air flow over the compressor aids cooling it. In our case, Cleave recommended against a deck intake and ER exhaust, as the air outside would be salt-humid. So, we exhaust the air which has crossed the condenser and the compressor. If the cabinet were not closed, air would not be (in our case pulled) efficient over the fins of the condenser.

Hope that helped.

L8R

Skip

[skipgundlach]

Further to my system with air only or with water...

So, this morning, as soon as the first cycle of the reefer and freezer quit, I set
the control to high, and turned off the water.

After more than 3 hours, when the freezer never cycled, at the next reefer
cycle, I turned the water back on.

29 minutes and nearly no temperature (box) change, it cycled. My take on it
is that the plates never were really getting cold enough, despite a constant
high-speed air-cooled input. Once the water was added, despite the lack of
box temperature change, the plates got cold enough for the probe to see the
trigger temperature, and it shut off, even though the box had little to no
change. 18 minutes later, it came on again...

In this period, the reefer went through 4 complete cycles, longer than
usual, as the incoming air wasn't as cold as it usually was. Runtimes were
more on the order of 40% vs the previously recorded 25%.

So: Air cooling on high won't keep up, let alone cycle. I'm sure, from
prior experience, that if I were to leave this on for a full day, the box
indicated temperatures would creep from the current high of 24 to over
"freezing" and the reefer would slowly take longer and longer to cycle,
eventually running full time.

The amphour delta for high speed compressor without, and medium with,
water cooling is strongly in favor of medium speed compressor and water
(see link to Sea Frost page which includes draw info). BD Series

L8R

Skip