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HVAC Guys, please read and comment?

Hal

Well-known member
Joined
Mar 8, 2008
Messages
659
Location
Vermont
Sap chiller I hope this link works.

All upgrades and improvements seem to come with their own problems. Last year I installed a reverse osmosis system in my sugarhouse. It increases the sugar concentration in maple sap from 1-2% up to 8-10%, reducing the time and energy required to produce finished syrup. However, it also raises the temperature somewhat, producing an excellent growth medium for various microorganisms, especially if the weather is unseasonably warm. One particular bacteria changes simple sugars to long chain polymers, resulting in what is called “ropey” syrup. It won’t flow through the pans properly, it foams up and boils over, and can burn the pan. There isn’t much use for the finished product, animal feed, or cheap tobacco flavoring.

Refrigerating the sap in storage will nearly eliminate the problem, and make better quality syrup in any case. If you have money to spend, you just buy a refrigerated milk tank and be done with it. If you have less money, you buy a commercial glycol chiller, and circulate the chilled glycol solution through some sort of heat exchanger in your existing tanks. If you are an absolute bottom feeder in the equipment department, like I am , you get really interested in something like the systems shown in the attached article.

I hope some of you will read this, comment and maybe give some useful advice. The article is mostly about adapting cheap window AC units, but he does mention the idea of a mini-split. The important part to me besides cheap, is to start with a sealed system, keep it sealed, and not have to do any actual AC service type work.
 
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jblnut

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Jan 17, 2015
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6,926
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In the Middle of MN
I just picked up an 800gal bulk tank with compressors and wash pump for $500. All in working order. The deals are out there depending on your area. I’m in a very heavy dairy area and there are a number of small farms that have sold out in the past couple decades with lots of equipment for sale. There is a 6,000gal setup locally for sale as well for $3,000. That’s a steal.
 
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Hal

Well-known member
Joined
Mar 8, 2008
Messages
659
Location
Vermont
I just picked up an 800gal bulk tank with compressors and wash pump for $500. All in working order. The deals are out there depending on your area. I’m in a very heavy dairy area and there are a number of small farms that have sold out in the past couple decades with lots of equipment for sale. There is a 6,000gal setup locally for sale as well for $3,000. That’s a steal.
Around here any tank, even plastic, will be at least a dollar a gallon. Stainless goes right up to three dollars, and any working refrigerated tank will five thousand dollars and up.
 
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fitter30

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Jun 23, 2019
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2,951
Location
Peace Valley,mo
Don't know what temp your looking for but window,mini and any unit design for comfort cooling. Lowest temp for space temp 65° is a high temp unit. Medium temp is a refrigerator 28° to 40°. Chiller for chilled water comfort cooling design is 40° supply. When you start getting out of the design if compressor happens to see liquid refrigerate will turn to junk right after it sees it. Any system that uses glycol has be for chilled or hot water not automotive. % not more than 50% no less than 30% for the inhibitors. The correct type glycol will have a slush % that will not freeze and break things.
 
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Hal

Well-known member
Joined
Mar 8, 2008
Messages
659
Location
Vermont
Don't know what temp your looking for but window,mini and any unit design for comfort cooling. Lowest temp for space temp 65° is a high temp unit. Medium temp is a refrigerator 28° to 40°. Chiller for chilled water comfort cooling design is 40° supply. When you start getting out of the design if compressor happens to see liquid refrigerate will turn to junk right after it sees it. Any system that uses glycol has be for chilled or hot water not automotive. % not more than 50% no less than 30% for the inhibitors. The correct type glycol will have a slush % that will not freeze and break things.
Did you read the article?

About the third instruction in the DIY list is to scrap the controls that came with the AC unit and substitute a low temp thermostat.

Chart in the article gives proper glycol concentration for slush free pumping and burst protection.

Looking for about 25-28degrees for the glycol, to chill the sap to below 35 degrees, ideally 30-32, depending on sugar content.

Under what conditions would liquid refrigerant pass into the pump? Temperature? Evap failure? Probably depends on type of refrigerant. I would think over pressure protection would kick in before that happened, but I can also see that a window AC unit might not have that.
 

Ohmthis

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Joined
Jan 20, 2013
Messages
2,992
Location
Outside of Louisville KY
Did you read the article?

About the third instruction in the DIY list is to scrap the controls that came with the AC unit and substitute a low temp thermostat.

Chart in the article gives proper glycol concentration for slush free pumping and burst protection.

Looking for about 25-28degrees for the glycol, to chill the sap to below 35 degrees, ideally 30-32, depending on sugar content.

Under what conditions would liquid refrigerant pass into the pump? Temperature? Evap failure? Probably depends on type of refrigerant. I would think over pressure protection would kick in before that happened, but I can also see that a window AC unit might not have that.
What he is stating above is systemic design. While those systems can be run to lower temps, by safe design, the controls stop them. When an evaporator coils get so cold, there isn’t enough heat in the air to achieve total evaporation. This introduces liquid refrigerant to the compressor. Slugging a compressor will kill it pretty quickly. Low temp systems are designed with controls (liquid line solenoid) and pieces (Suction line Accumulators) in the refrigeration circuit to prevent this.
 
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