Temperature Control In Air Coolers - Possible? Ideas?

Replies

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  Ramani Aswath

  In evaporative coolers there is a minimum temperature fixed by the relative humidity of the inlet air. One can fit a thermostat to switch of the blower for any set temperature above this minimum. Unfortunately the user has no way of finding this minimum without psychrometric data of the ambient air, which varies considerably.
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  Kaustubh Katdare

  No more responses. #-Link-Snipped-# , I was expecting your comment.
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  ISHAN TOPRE

  In AC, liquid gases are circulating which absorb the heat and supply fresh, cool air. This is the single biggest difference between air cooler and air conditioner. However employing this coolant (refrigerant) is a costly affair.
  
  For people in India, as far as I have seen opt for low cost options. It is better to use a cooler worth INR 5000. The life can be as high as 10-25 years depending upon the use. We use cooler for around 3-3.5 months.
  
  If we use AC, there are maintenance issues. People do not always want to invest 30000-50000 and have higher electricity bills.
  
  Operating cost of cooler is very very low as compared to AC.
  
  Nowadays latest models of AC are coming in market guaranteeing high COP.
  Now coming to your question, using temperature control (present technology) in cooler will increase its cost to a level where you will say, AC is better.
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  Kaustubh Katdare

  I'm specifically interested in finding out whether we can control the temperature of the air blown by the air-cooler. How about regulating the flow of water? Can that help?
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  Ramani Aswath

  The air coming out of the blower will be always at the wet bulb temperature at that place and time. One possibility is to have two blowers. The second blower just blows the plain air without passing through the evaporative section. The temperature control can perhaps be used to mix these in required proportion to get the desired final temperature.
  Not an elegant solution, I guess. It will work though.
• 

  ses

  Kaustubh Katdare

  I'm specifically interested in finding out whether we can control the temperature of the air blown by the air-cooler.
  How about regulating the flow of water? Can that help?

  You must be familiar with cooling tower design which works on the same principle of evaporative cooling.There are two variables namely air flow rate and water flow rate which are determined to arrive at the desired wet bulb temperature.It is possible to vary both the variables through fan speed and water pumping rate.However,we seldom get to the exact wet bulb temperature due to efficiency losses.Similarly, it is possible and sometimes necessary to control the outlet temperature in a air cooler say in a place like Hyderabad where the dry bulb temp in peak summer is around 44 deg C and RH as low as 8%.This gives you a wet bulb temp of around 16 deg C,which is far lower than the comfort temperature of 24 deg C to 26 deg C.We can achieve comfort temperature by lowering the fan speed,and most models come with 2-3 fan speed settings.The water pumps in most models come with fixed speeds and pumping rates,and hence not possible to vary the flow rates, though theoretically possible to vary them with VFDs.