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Thread: Solar Assisted A/C
08-09-2011, 02:49 PM #40Regular Guest
- Join Date
- Dec 2009
- Central Florida
The collector is nothing more than copper tube bent into U shapes with each U inside of a glass tube. The tubes are filled with soybean oil and are connected to an oil reservoir at the top of the collector. I think the total capacity was around 4-5 gallons.
08-09-2011, 06:30 PM #41
That pdf has some misinfo in it. Here is a quote from it:
The conventional air conditioning system is only able to change a portion of the gas into a liquid state so as when the refrigerant enters into the metering device it is a saturated vapor.
08-09-2011, 06:47 PM #42
I saw something like this come over the fax machine 6 or 7 years ago. What's missing is the Perpetual Motion Machine required to make it work.
08-09-2011, 07:27 PM #43
08-09-2011, 07:29 PM #44
08-09-2011, 07:37 PM #45
R407c is what is used. According to the ad.
What a bunch of horse hockey.
At best it is just bells and whistles that break.
With all the Pros on this site, Has anyone ever worked on one or installed one?????Never give up; Never surrender!
08-09-2011, 07:56 PM #46
08-09-2011, 08:01 PM #47Professional Member*
- Join Date
- Feb 2006
- Float'N Vally, MS
There is another thread were Tass was field testing this thing......
Last edited by behappy; 08-09-2011 at 08:18 PM.Life is too short, Behappy!
08-09-2011, 08:14 PM #48Professional Member*
- Join Date
- Mar 2010
08-09-2011, 08:28 PM #49
I'm getting dog piled and can't defend myself 'cause Hells Kitchen is on. I'll be back....An answer without a question is meaningless.
Information without understanding is useless.
You can lead a horse to water............
08-09-2011, 09:07 PM #50
How does the condenser reject the added heat ?
If the condensing unit is a standard item - how does it reject all the solar added heat?
Why does the condensing of refrigerant start at the beginning of the condenser?
Where is this working unit on display?PHM
08-10-2011, 12:43 AM #51
From the pdf posted by Tips:
The working fluid leaves the compressor as a hot, high pressure gas and flows into the condenser. Correct.
The gases enter the condenser coil and begins cooling and changing back into a liquid at the bottom 1/3 of the coil. Incorrect. The bottom 1/3 on most of today's condenser coils are subcooling circuits.
When the working fluid leaves the condenser as a semi liquid, its temperature is much cooler and it has changed from a gas to a liquid under high pressure. Incorrect. If subcooling is normal, refrigerant leaving the condenser is subcooled liquid, not a semi-liquid.
The liquid goes into the evaporator through a very tiny, narrow hole. On the other side, the liquid's pressure drops. When it does it begins to evaporate into a gas. They got that right at least.
As the liquid changes to gas and evaporates, it extracts heat from the air around it. The heat in the air is needed to separate the molecules of the fluid from a liquid to a gas. It's called phase change. Energy is required for this to happen. Air happens to be the medium in this case that has sufficient heat content to sustain phase change throughout the evap coil.
By the time the working fluid leaves the evaporator, it is a cool, low pressure gas. It then returns to the compressor to begin its trip all over again. Got that right.
A solar air conditioner uses a solar panel (not electricity) to super heat the refrigerant (the hotter it is...the higher the energy saved) How so? If that's the case, why have OEMs spent so much time making condenser coils much larger in proportion to compressor capacity in order to provide better rejection of discharge superheat and simultaneously lower head pressure? to deliver a super heated higher pressured gas to a condenser and then to the evaporator and then to the Solar Compressor. "Solar compressor" my foot. It's a conventional compressor being tortured by high head pressure and piss poor suction superheat.
This super heated gas enters the coil and begins cooling and changing back into a liquid at the very top of the coil. Same happens in conventional condenser coils. Probably sooner than the "solar" version.
When the working fluid leaves the condenser, its temperature is colder and it has changed from a gas to a liquid under high pressure. It's not cooler because heat over and above heat of compression/discharge superheat was added prior to refrigerant entering the condenser coil.
By the time the working fluid leaves the evaporator, it is a cool, low pressure gas. It then returns to the solar panel to begin its trip all over again. According to the diagram it first returns to the "solar compressor" prior to re-entering the solar array.
The Sedna Aire Solar Absorption Air Conditioning System uses a different method. It uses the solar heat from the sun to superheat the refrigerant and delivers it directly to the condenser...by passing the compressor. The superheated refrigerant enables the refrigerant to begin changing state at the top of the condenser coil as well as utilizing more of the condenser cooling face of the coil (not ust the bottom two thirds). They insist on incorrectly stating that conventional condensing coil phase change takes place toward the bottom of the coil. No! The lower third of the coil is a SUBCOOLING CIRCUIT! Get it right! You can't have subcooling unless complete phase change has occurred.
AND there's no way to bypass the compressor and still hope this thing might work. Superheating the refrigerant does not provide the second of two points of pressure separation that the combined team of metering device and compressor do. What happens when a compressor has weak valves? The system pressures get closer together. What happens when there's NO compressor? Hmm...
The Sedna Aire process allows more of the refrigerant to change state back into a liquid faster as well as allowing the transformation of more liquid into the metering device. Liquid refrigerant does not "transform" at the metering device. It passes through the metering device and experiences a pressure drop due to expansion into a larger volume of space in addition to the restriction of mass flow. Evap coil tube diameter is larger for more than one reason.
"In this house we obey the laws of thermodynamics!"
- Homer Simpson
08-10-2011, 08:34 AM #52Regular Guest
- Join Date
- Dec 2009
- Central Florida
I'd really like to find anyone else that has/had one of these things and find out what they did to resolve their issues with the manufacturer.
Also, I really wished I had looked "under the hood" to realize I was paying extra to blow up compressors and void warranties.