Direct use of geothermal energy in Menengai, Kenya : proposed geothermal spa and crop drying

Abstract

Direct use of geothermal heat as an energy source has significant economic and environmental benefits. Its use increases the utilisation efficiency of geothermal resources compared to electricity generation only. The use of geothermal heat in Menengai, Kenya, for bathing and drying of agricultural crops is proposed is this report. A geothermal spa of 2800 m2 in water surface area, requiring 35 kg/s of geothermal flow is designed. Three location scenarios of the lagoon in Menengai field are evaluated with regard to pipeline cost. Conventionally heated swimming pools including an outdoor pool, indoor pool, steam room, wading pool and three hot tubs with a total water surface of 700 m2 utilising 55 kg/s of 130° C geothermal fluid are analysed. Utilisation of geothermal heat for drying is demonstrated through the design of a 30 m3 mobile grain crop dryer comprised of a drying chamber, water-air heat exchanger and a blower. For air re-circulation purposes, a diversion valve from the tunnel to the bed dryer is provided for. The dryer requires 2 kg/s of 130° C geothermal water and has a capacity of 3 ton/hr of grains.