COUNTERFLOW PARTICLE-TO-PARTICLE HEAT EXCHANGE. PART II. DESIGN AND PERFORMANCE OF A PROTOTYPE.

A machine providing an improved heat transfer/heat recovery mechanism has been developed for processing rain. The heat exchanger discretely mixes and separates grain with a high density heat transfer medium in a counterflow configuration. The device is divided into three stages, one for heating grain, one for recovering energy from the grain, and one for inputting energy to the heat transfer medium. Material flow tests using wheat and table salt show satisfactory separation and distribution. Steady-state heating experiments conducted on a 5 cell/stage prototype produced temperature increases in wheat in the range of 25 to 40 degree C and thermal efficiencies up to 84%. Of the energy absorbed by the wheat in the heating stage, an average of 68% was recovered in the cooling stage.