Buying a New 3 way Fridge/Freezer

[cuthound]

Adsorption fridges are usually 2 stage and use something like silica gel to adsorb evaporated moisture under a vacuum. Once the silica gel is saturated, they switch to a second stage of dry silica feel and use the heat source to dry out the saturated silica gel in the first stage. Once the second stage is saturated, colling is transferred to the forst stage and the cycle is repeated.

 

Edited to add the bit about the evaporation taking place under a vacuum.

Edited January 31, 2017 by cuthound

[DandV]

Kerosene Fridges were common in both the New Zealand and Australian outbacks in areas without power reticulation. Some may still be in use but most were superseded by lpg fridges and then by electric fridges coupled to solar and or wind generation.

Don

[MtB]

Kerosene Fridges were common in both the New Zealand and Australian outbacks in areas without power reticulation. Some may still be in use but most were superseded by lpg fridges and then by electric fridges coupled to solar and or wind generation.

Don

 

 

I want a kerosine fridge!

 

Thanks for your answer. What's 'power reticulation'? I thought reticulation was what pythons did with their jaw when they swallowed a goat...

[DandV]

I want a kerosine fridge!

 

Thanks for your answer. What's 'power reticulation'? I thought reticulation was what pythons did with their jaw when they swallowed a goat...

Kerosene Fridges were an amalgam of a kerosene wick heater and an absorption fridge with the temperaments of both. Reluctant to start and prone to stopping, flareing and emitting both soot and kerosene scent. Refuelling and relighting was an invariably messy and smelly. Trimming the asbestos wick both an art and probably dangerous with asbestos exposure.

The posh way of describing reticulated electricity is "on grid".

[Tony Brooks]

 

Ok, google knows nothing about adsorption as a technology... What is it please?

 

Google "how a gas fridge works" and you will get the results. It does not use silica gel but a mixture of ammonia and water. The heat vaporizes the ammonia to a gas that moves to a separate chamber where it condenses back to liquid or so Google says. I know they contain ammonia because we had the odd unit leak.

[mross]

 

Google "how a gas fridge works" and you will get the results. It does not use silica gel but a mixture of ammonia and water. The heat vaporizes the ammonia to a gas that moves to a separate chamber where it condenses back to liquid or so Google says. I know they contain ammonia because we had the odd unit leak.

Adsorption and absorption are two different technologies......................

[cuthound]

Google "how a gas fridge works" and you will get the results. It does not use silica gel but a mixture of ammonia and water. The heat vaporizes the ammonia to a gas that moves to a separate chamber where it condenses back to liquid or so Google says. I know they contain ammonia because we had the odd unit leak.

Tony, with all due respect you have described an absorption fridge. Typicaly commercially they use a bromide solution for the refrigerant with domestic ones like the Dometic using an ammonia solution.

 

I have worked on several projects using these and owned a share in a boat with a Dometic 3 way fridge.

 

Adsorption fridges work as I described. I have only ever installed one in this country, in the Waitrose store in East Cowes IoW, where all of the stores refrigeration requirements were met by an adsorption chiller using water heated by waste heat from Stirling engines.

 

http://www.mitie.com/news-centre/case-studies/energy-services-case-studies/waitrose_2

[cuthound]

google knows nothing about adsorption as a technology... What is it please?

Found this on Wikipedia.

 

"Adsorption chillers

 

Combining an adsorbent with a refrigerant, adsorption chillers use heat to provide a cooling effect. This heat, in the form of hot water, may come from any number of industrial sources including waste heat from industrial processes, prime heat from solar thermal installations or from the exhaust or water jacket heat of a piston engine or turbine.

 

Although there are similarities between absorption and adsorption refrigeration, the latter is based on the interaction between gases and solids. The adsorption chamber of the chiller is filled with a solid material (for example zeolite, silica gel, alumina, active carbon and certain types of metal salts), which in its neutral state has adsorbed the refrigerant. When heated, the solid desorbs (releases) refrigerant vapour, which subsequently is cooled and liquefied. This liquid refrigerant then provides its cooling effect at the evaporator, by absorbing external heat and turning back into a vapour. In the final stage the refrigerant vapour is (re)adsorbed into the solid.[14] As an adsorption chiller requires no moving parts, it is relatively quiet."

[WotEver]

I'm intruiged by the last phrase: "relatively quiet". From the description it sounds silent. Does it perhaps gurgle?

[MtB]

Thanks for this Mr Hound. I had no idea adsorption refrigeration technology even existed!

 

Still don't really understand how it works. The Wiki description throws up a load of questions in my mind. Seeing one would probably help!

[WotEver]

Thanks for this Mr Hound. I had no idea adsorption refrigeration technology even existed!

 

Still don't really understand how it works. The Wiki description throws up a load of questions in my mind. Seeing one would probably help!

Indeed. "Which subsequently is cooled and liquified..." leads one to wonder 'by what mechanism?'

[Tony Brooks]

Sorry - I thought it was a spelling or autocorrect mistake.I see now.

 

Cheers

[MtB]

 

Sorry - I thought it was a spelling or autocorrect mistake.I see now.

 

Cheers

 

 

 

I thought the same when I read Mr Hound's first mention of it.

 

Do you know anyting about this technology Tony? The Wiki page totally ducks out of explaining properly how it works doesn't it!

[cuthound]

I'm intruiged by the last phrase: "relatively quiet". From the description it sounds silent. Does it perhaps gurgle?

 

The only adsorption chiller that I was involved with couldn't be heard in the plant room it was located in. Mind you there were numerous large pumps operating, to circulate the hot water produced by the Stirling engines and the chilled water produced by the chiller, so if it made only a quiet noise it would have been drowned out

 

 

Thanks for this Mr Hound. I had no idea adsorption refrigeration technology even existed!

 

Still don't really understand how it works. The Wiki description throws up a load of questions in my mind. Seeing one would probably help!

Not much to see really. If you Google "commercial adsorption chillers" then look at the images you will see a few, from small to large.

 

Water is used as a refridgerant and it is adsorbed to silica gel under a slight vacuum to provide cooling. There are two silica gel containers. When the silica gel container is fully saturated, it automatically switches to the second silica gel container to continue to provide refrigeration, and the first container is dried out (regenerated) using the heat source, in this case waste heat from the Stirling engines.

 

Apart from its physical size (much larger than an equivalently rated compressor chiller) the only issue is the non-linear cooling it provides (it cools well at first and performance drops off as the silica gel becomes saturated). However this is easily dealt with by utilising a buffer vessel of chilled water to smooth out the "lumpy" cooling performance.

 

This link shows an image and an explanation of how it works, however their video appears not to work.

 

http://www.bryair.com/product/adsorption-chiller-17/adsorption-chiller-40?categoryID=17&gclid=Cj0KEQiAiMHEBRC034nx2ImB1J0BEiQA-r7ctnfkf-yEfqmdxEDjPWb1b3nACaGcgarMZd5adBgmrTsaAs6Z8P8HAQ

[WotEver]

White paper from within that link: http://www.bryair.com/uploads/products/pro_image/White%20Paper.pdf