Air Conditioners that Use Water as a Refrigerant

<...Is it possible to prepare air conditioner like this...>

Evaporative cooling towers are widely used as a source of "coolth" for all manner of processes, including air conditioning.

<...some chart where I can get at what pressure and at what altitude water starts boiling below room temperature...>

Please refer to a set of Steam Tables.

<...method of generating vaccum on surface of water...>

The maximum vacuum that can be generated is that which is related to the temperature of the water, and can be looked up in Steam Tables.

Try Mayhew & Rogers, "Thermodynamic Properties of Fluids", any edition, or Perry, "The Chemical Engineer's Handbook", any edition, or "Kempe's Engineers' Yearbook", any edition.

http://en.wikipedia.org/wiki/Absorption_refrigerator

Sorry, you have boiling confused with evaporation. Go back to square one.

Hi Lynlynch,

I think you are wrong on that one. The water is boiling. Evaporation only takes place at the surface of a liquid but boiling takes place wherever the temperature is above boiling point, which is related to pressure.

The height of mountains used to be measured by the temperature that the mountaineers cuppa would boil at.

regards

Chas

There are some very reliable absorption coolers that use the process you are describing. As an added bonus, these are typically powered with a heat source instead of electricity.

the system under discussion is already available known as VAM chillers works on vapour Absorption machines its economical if you have clean waste exhaust heat from power plants using gas turbines.otherwise you will end up 10generating lot of green hose gases 2: making a big drain into your pocket in terms of money spent on fuel for generating required heat.and last but not least operation and maintenance issues.

crm

Hi,

Absorption chillers do work under a high vacuum and therefore the water boils at a reduced temperature but the active process is one of concentration (by boiling off water, this is where the heat is added) and dilution of the previously concentrated solution this is the endothermic part of the process.

The cooling effect is purely due to the energy exchanges which occur through changes in concentration of the solute which may be lithium bromide.

This is called Vapour absorption cooling and does not need electricity. In fact before electricity was developed, Vapour absorption cooling system was in use. With electricity in short supply and unreliable in availability, this is more popular and cheaper. You can use cheap fuel, maintenance is also very less(almost no moving parts except the chilled water circulation pumps). I think Thermax Pune, India is the leading manufacturer in the world.

0.5 psi gets you down to 26.4°C Just extend the line on this graph a bit.

http://www.engineeringtoolbox.com/boiling-point-water-d_926.html

Hi,

Yes any set of steam table will show you the relationship between the temperature of the fluid and vapour phases in the sub-atmospheric condition. You will be very disappointed I guess when you discover that with probably the best vacuum you can get (1kPa) will have an equivalent liquid temperature of 6.98C.; and at just 2kPa this becomes 17.51C.

So your process will not be able to enjoy the coolth that you might wish.

You can employ the vacuum as part of a different process referred to as absorption cooling but thats another story.

This minimum temperature has always bedevilled steam engineers who rely on ambient air cooling for condensers.

However at 11.45 pm the Marine Engineers aboard RMS Titanic must have been very happy bunnies as they were getting a surperb vacuum thanks to the freezing cold water entering their condensers.....didn't last long did it!!

Such a system has been in use for nearly a century. It is called Steam Jet Cooling, and uses only water (liquid and steam phases). A standard steam air ejector is used to create a partial vacuum in a vessel containing water, typically 0.9 kPa. At that pressure, the boiling point of water is ~5° C.

Some of the water changes phase (boils) to steam. The energy required for the phase transition is taken from the remaining water, sub-cooling the liquid to ~4° C. The subcooled water is pumped through the chilled water distribution piping to heat exchangers in local air handling units. The water is returned to the vacuum vessel to complete the cycle. Spray nozzles are used to atomize the water for better heat transfer in the vacuum vessel.

This system is very useful in plants where excess process steam is available (steam turbines, paper mills, etc.), but is very inefficient if a dedicated steam generator must be used. Further information can be found at http://en.wikipedia.org/wiki/Steam_jet_cooling. An interesting use on steam-powered passenger trains is shown at http://www.atsfry.com/Passenger/steameject/steamejector.htm.

Augment luxurious standard of living with dynamic contribution of used Air conditioner that does not accelerate consumption of electrical units rather rewards you with its cooling capacity. Relishing features of used items sometimes cause irritation but if you check before time performance, it will be convenient to manage without facing mechanical issues. Every model including Ductless AC, Split AC, Portable AC, and Window AC are available in recycled form, you just have to define your AC requirements to the dealer and he leads you to the right selection of affordable cooling device. Air conditioners not only control temperature to bring it to comfortable level but also purify air.If you want to get more information, click here,

http://used-airconditioners.com/