Hi Vishnu, I think it is a good question. because plenty of energy is being wasted in traditional active cooling. An alternative method is to utilize passive cooling. The concept is to use a fluid with high thermal capacity in order to trap the heat of base stations, then dissipate this heat during the night. Try to search for "passive cooled shelter" on the web.

Thanks Dr.Akram Hourani 

Passive cooling on BTS equipment continues to be a challenge in the hottest parts of the world. Equipment manufacturers have passive cooling systems that work reliably in the temperate regions, but still need some help from active cooling in tropical and desert climates.

Solar shields on the outside of cabinets afford some help. They are simply another layer of thin, light colored material mounted 5-10 cm away from the exterior of the cabinet. The bulk of the solar radiation is absorbed by the sheet of material, and the air circulation behind it removes the heat. This technique can significantly reduce solar heat gain into the cabinet.

However, a solar shield doesn't help at all for the waste heat coming off the equipment. Most of the BTS equipment in service today can operate at 40-50 C without a problem. So for the radio equipment, getting the temperature below 30C is not nearly as critical as it was with past generations of BTS hardware. What we try to do in the industry is get the temperature down to the maximum the BTS equipment will safely operate at. Forced air cooling could potentially bring the temperature down further, but then you are moving such a tremendous volume of air that filters tend to foul much faster, increasing maintenance costs and the chance for failure (if the filter clogs before a technician can get to the site). It's a difficult balance, moving enough air to be effective, but not so much that filters and heat exchangers clog up every few weeks.

The batteries, as you point out, will fail quickly when exposed to temperatures >30C for extended periods of time. This remains a challenge for the industry. Temperature compensated charging implemented on the DC power plant is the simplest method and supported by most DC power systems today. The voltage decreases as the battery temperature increases, reducing the potential for battery gassing. It helps, but is not enough for the hottest climates.

Some battery manufacturers offer battery chemistry that is optimized to work in a high temperature environment; again that affords some help but doesn't completely solve the problem.

I've even heard of some experimentation with "burying" the batteries in a vault next to the radio cabinet, taking advantage of the cooler earth. Coincidentally, this might also help deter battery theft which is a huge problem in the telecom world.

An approach you might consider is to treat the radio equipment and the batteries as separate problems. If the radio equipment is happy operating at 40-50C. Let it run that hot; a free cooling system won't have to move as much air and the system won't have to be cleaned as often.

A combination of two or more of the techniques I mentioned above could address your battery challenges. And if all else fails, there was some experimentation with flywheel energy storage systems for remote cell sites in hot climates back in the 1990's. As far as I know, it never took off. It was too expensive and traded one set of reliability problems for another. I don't know if there is any work going on today with flywheel energy storage.

-Mike H.

Correct Mr.Michael Hainzl .. In Telecom, Battery Theft & Diesel Theft is the major problem... No a days Solar panel also going to theft. Loft of practical problems are there in Power plant and Telecom Industry ..