Abstract. One of the main constraints of biomass fuel utilization in a small scale rice drying
system is the operating difficulties related to the adjustment of combustion/feeding rate. Use of
thermal storage may reduce the problem since combustion operation can be accomplished in a
much shorter time and then the use of heat can be regulated by simply adjusting the air flow.
An integrated biomass furnace-rock bed thermal storage with a storage volume of 540 L was
designed and tested. There were four experiments conducted in this study. Charging was
performed within 1-2 hours with a combustion rate of 11.5-15.5 kg/h. In discharging process,
the mixing of air passing through the rock bed and ambient air were regulated by valves.
Without adjusting the valve during the discharging process, air temperature increased up to
80o
C, which is not suitable for rice batch drying process. Charging with sufficiently high
combustion rate (14 kg/h) within 1 hour continued by adjusting the valve during discharging
process below 60o
C increased the discharge-charge time ratio (DCTR) up to 5.33 at average air
temperature of 49o
C and ambient temperature of 33o
C.The efficiency of heat discharging was
ranged from 34.5 to 45.8%. From the simulation, as much as 156.8-268.8 kg of rice was able to
be dried by the discharging conditions