Cooling Degree Days for Estimating Energy Consumption in Air Conditioning Systems in Nigeria

—The effect of change of ambient temperature on energy demand for cooling or heating can be estimated using degree days. In this work, cooling degree days were computed from hourly dry bulb temperature data of eighteen locations spread over the six geopolitical zones in Nigeria. The raw hourly dry bulb temperature data which were obtained from Nigerian Meteorological Agency (NiMet), Oshodi, Lagos for fifteen years of either 1994 -2008 or 1995 – 2009, were digitized and then analysed to obtain cooling degree days using the following base temperatures: 22, 24, 25, 26, 28, 29 and 30°C. The minimum and maximum annual cooling degree days for all base temperatures were obtained for Jos and Sokoto, respectively. For a base temperature of 22°C, the annual cooling degree days obtained ranged between 18.18 and 2429°C-day. Fourteen out of eighteen locations had their highest monthly cooling degree days in March, three other locations had theirs in May and only one has its own highest in April. The lowest monthly cooling degree days were obtained in August for all the locations. The results obtained in this work are useful for energy management in Nigeria and it may also be useful in other countries with cities having similar climate to the locations considered in this work.