Coolers ?

The Indian restaurant in Watford had a problem tonight with their proper a/c unit.

They had bought a freestanding unit that certainly gave out a stream of cooler air, hardly enough but you could feel it was cooler than ambient.

This had no external heat vent and did not seem to be increasing the humidity.

How did it work? Can anyone with at least "O" level physics give a scientific explanation?

The meal was excellent but the only conclusion I could come to was it acted as a dehumifier and removed the latent heat of vaporisation of the moisture in the air.

Does anyone know the correct answer?

Tony

They had bought a freestanding unit that certainly gave out a stream of cooler air, hardly enough but you could feel it was cooler than ambient.

Click to expand...

There are several different methods used and given the lack of any external vent pipe and this ones limited cooling effect it sounds like the most basic (cheapest) method. That is where they are filled with cold water and a fan is used to blow air across the cold water, cooling the air until all the water has evaporated and then it gets refilled.
Top of the ranges use compressed coolant (ala fridge mechanism) and de-humidify = exhaust pipe to take the extracted heat away.
So, you can either extract the heat (better but more expensive and need extractor pipes) or, merely blow cool air into the environment (not as good but cheaper and slightly more portable).
Hope the curry was still hot.

If it was the evaporative type, I do not see how these work any better than a plain fan. Yes, they WILL reduce the temperature as measured by a thermometer, but they do this by increasing the humidity as they evapourate the water. Thus the amount of HEAT in the air remains the same. From a persons point of view, evapouration is what makes them cool, which can be done by a plain fan.

Not trying to justify them oilman, just answering the question.

It's ok, I wasn't arguing, I was just penning some thoughts I have had about these things.