can we use cotton in desert cooler for obtaining cooling

presuming your desert has water, evaporative cooling is a proven technology. BUt you lose the water...

Frankly, I would run solar panels ( not photovoltaics) in reverse at night by thermosiphon technique to chill a mass of water/water glycol to maintain a large cool thermal mass. then circulate the water through heat exchangers with fans to chill room. reradiate heat out each night. There is one little detail however that I will not give you about this setup.

You are the final year engineering student.

milo

In Australia, over a hundred years ago, people in the dry and arid outback used a device called a "Coolgardie Safe". Look it up in Google. Basically it used a flywire encased box with a water tank on top. Hessian flaps were laid in the tank and hung down the sides, drawing water through the top of the hessian by capillary action. Evaporation of the moisture from the hessian caused the cooling effect (you are the engineering student so you can calculate why it cools). The 'safes' often stood in tin trays which collected any excess water and provided a 'moat' to keep ants out. I can see no reason why cotton could not be similarly used (hessian is normally woven from jute fibre).

Foe what it is worth I can still remember my mother using one before we got our first kerosene fridge about 55 years or so ago. It NEVER got cool enough for ice cream though!!

Regards,

Pete.

I don't think the "sucking" idea would work.

You as the designer can do an easy test. Hang a piece of the cotton material in water and measure the achieved "sucking" height.

If it is high enough with enough flow you have a solution else back to the drawing board!!!

I would also suspect that the weave of the cotton affects the height to which the water is wicked (not wicked, but wicked)

First the basic question Why do you want to use cotton? a) Do you have idea cotton is biodegradable, in presence of water (soaked) and air how many days do you think it will stand ? b) If you treat it, you lose whatever capilaries are there, anyway these will not be useful to gain the height. c) What about the salts in water which are going to clog whatever capliaries are there sooner or later- or you want to use distileld water ? d) Assuming you have already electricity to run the fan (or other means) why dont you use the same to run the pump too ? e) what is the saving you expect from avoiding the pump (in units ?) Vs the fan units ? f) The restriction in the flow of air (due to excessive cottons) may have to be compensated by fan power. Do you want to design a thing just for the sake of just to see that it can be done or for it to have a practical application ?

My experience of years ago with swamp coolers of various designs suggests that cotton would not be an appropriate material, due to a propensity to degrade rapidly due to mildew/mold contamination in a moist environment. Wool might be a more appropriate material. Most of the units with which I had experience used a sort of woody plant fiber, but I do not remember what that was...

Most of the units with which I had experience used a sort of woody plant fiber, but I do not remember what that was...

Burlap works just fine.

Nearly 22 years ago after my wife and I were married we were living in Kansas City. Our first appartment had no AC and a Southern exposure.

I opened one window and covered the opening with burlap and had the bottom of the burlap in a tray of water. I also had a fan to draw air through the burlap.

The water was drawn up the burlap by capilary action. It worked fine and we got through two summers quite well.

Just the way a cooling tower works, the hot air gives up energy to evaporate the water. The incoming air has less energy (heat) and higher humidity.

Travis

The material asked,may be is zeolita, not cotton,some monthes ago i thought to use exactly the same idea only thinking in bricks i found later a lot of information about and differents reserchers papers,a lot of experiences already made.I think you should collect information before do nothing.This is one of the most interesting fields for research with fast application.If you are still intrested i'll send you what i collected.

sir,thank you for your idea ,sir if you really have details regarding this topic please mail me at email id- rajeev_company@yahoo.co.in

thank you

I collected some 30mb of informatin in hd some else printed...If you don't get anything by simple browsing in internet these titles i promise i'll send you the entire document so try first:I don't send about theory like water flux thru porous material or adsorption /desorption/vaporization heat from porus surfaces/water-alumina,water-silicagel cycles drying porous media,etc. theories.I took only the free of charge papers:

"Experimental study of multytype macromolecule porosity moisture-conditioned material" by Xiang Huan,Ying Fan,..Shenzhen China (envelope tech. for building energy efficiency;"Moisture buffering effects on indoor air quality experimental and simulation results", ASHRAE;"Energy saving construction techniques performed by the "House energy doctor",Nader V.Chalfoun U.OF Arizona;"Design and applicationof natural down-draft evaporative cooling devices" Chalfoun;"Passive down-draft cooling systems using porous ceramic evaporators" WSP Enviromental LTD,U. OF Nottingham,Axioma Lab.Switzerland;"HVAC multifamily buildings" buildingscience.com;;

Commercials developments:Evaporative cooling Met Mann,Coolbreeze,Donaldson;Heat pipe technology,Inc;Icogen-Nishiyodo;Rotartica S.A.(www.rotartica.com);Cabesti S.R.L.(dryier without heat);Geoexchange system;;

There are interesting researchs or basic theory explanation in differents languages too:"Actividades de investigacion y desarrollo en el área de enfriamiento solar en el centro de energía renovable y uso racional de la energía" U.Nac. de Ing. Lima,Perú;;

You should browse too in Wiki:Misting systems,evaporative cooler,cooling towers,chillers,windcatcher,stack effect;;May consult patents files like wo 93/13368 Gomez Matinez;;

OK,my friend was a lot of time reduce so the spreaded information i had,hope be useful and let me know...

very less air will pass through cotton. in desert cooler , the fan sucks air from the cut or fins of the sides. if u will place cotton in the fins instead of juet net. very less air will pass through cotton.

A non mechanical means of cooling was patented by a tribe member in Africa. It consists of a large unglazed clay pot, with a smaller pot inside.The space between the two pots was filled with sand, and soaked with water. The evaporation of the water through the porous outer pot created the cooling .There was claimed to be a 20 to 30 degree differential between inside and outside temperatures. Perhaps this will suffice for your project? ------------------------HTRN-----------------------------------------------------