Studies on Hay Dryers with Heated Air (I)

A Comparison of Performances between a Kerosene Dryer and a LP Gas Dryer

Abstract

Experiments were made for a comparison of performances between two hay dryers, one with a kerosene burner and the other with a propane heater. Mixed hay with 80% red clover and 20% timothy was used. The findings were as follows.
1. The propane dryer, in general, showed higher thermal efficiencies than the kerosene dryer. The difference in thermal efficiencies seemed to have come from the differences in dryer box design, which brought about different material bed depths, bulk densities, flow rates of heated air per unit floor area and static pressures. Many unknowns, which further have to be investigated, prevented the author from securing the optimum operation of the dryers from the standpoint of fuel and time economy.
2. Using hay which had been field-cured to 35-40% moisture content (wet basis), and making 10tons of hay annually, both fuel and depreciation costs of either dryer were approximately the same, the total being 3.15yen per kilogram of dried hay.
3. The capacity of either: drier was too small for efficient hay making in Hokkaido. For those farmers who prepare 10tons of hay for five cows a year, a double size may be desirable and for those with ten cows, a quadruple size seems to be necessary.