Free cooling and indoor humidity level in telecommunication base stations

Free cooling is a well-proven method for reducing power consumption in thermal management of telecommunication base stations compared with traditional approach (running air conditioning all over the year). However, some operators still have some concerns in using free cooling especially when outdoor air is very humid or polluted. This article addresses the humidity concerns with an analytical approach. Basically, by increasing the temperature, the humidity ratio is reduced. Based on this principle an analytical model is applied for some case studies. Based on the results, if the temperature for an extremely humid air (relative humidity of 99%) is increased in the range of 2–3 °C, its humidity is reduced to a risk-free level (85%). Furthermore, this article suggests some controlling strategies and a concept design for servers that potentially reduce risk of damaging IT equipment in humid weather condition.