Improved energy efficiency of farmers' cooperative litchi drying operation in N orthern T hailand

In 2007, Hmong farmers growing litchi in the mountainous region of N orthern T hailand started to dry the fruit in response to its declining market price. However, the locally available dryer, although affordable and of a size appropriate for smallholder farmers' cooperatives, showed excessive gas consumption, and this, along with rising fuel costs, imposed a threat to the drying operation. The objective of this study was to test low‐cost, easy‐to‐implement modifications to a locally available convection dryer, to improve its energy efficiency. Experiments were conducted in cooperation with a H mong farmers' cooperative in N orthern T hailand. Insulation of the air ducts and control of the air recirculation rate led to energy cost savings of US $2.45 per dryer‐load. With the modifications required being simple, the investment needed was recovered after only approximately 20 loads, while the energy efficiency of the dryer increased from 33% to 39%.