Desenvolvimento de uma bomba de calor para secagem de produtos termosensíveis: sementes de feijão (Phaseolus vulgaris L.) variedade "carioca".

Abstract

This work shows the use of a heat pump thermosensible products drying, developed from a home air conditioner device, with cooling capacity of 18.000Btu/h, which has been changed for the experience, by replacing the formal propeller, adding a condense device and putting two rubber joints. Two drying tubes were also added to this device. The system like this constituted it allowed the production of hot air for drying of the bean beans in the first chamber, and the production of air with low relative humidity and temperature, for drying of beans seeds in the second chamber The bean beans were dry of moistness rate of 69, 65 and 60% moist basis, even own rate moistness for it thrashes it, using the drying air flow of 18,8m3.min'2m"2 and air temperature of 50°C (±0,5°C), during this drying there has been a average decrease of thirteen percent in the moisture content of the beans. Soon after, the beans were thrashed and the coming seeds of that thrash they were dry of a moisture content of 25 to 14% type dried. That drying has been conducted at a temperature of 31°C (±0,5°C), relative air humidity of 29% (±1%) and an outflow of 5,61m3.min"2.m"2. During the haricot drying process, the heat pump energy consumption was l,12kW.h per evaporated water kilogram, in the seed drying it was 4,65kW.h per evaporated water kilogram, and during the concurrent haricot and seed drying, the consumption was 0,9kW.h per evaporated water kilogram. The coefficient of the heat pump performance, working with and without load in the seed dryer, was 4,6 and 5,3, respectively. After drying seeds kept satisfactory germination strength. All this matter, along with drying efficiency shown by the system, demonstrates how feasible the use the heat pump is, also in the thermosensible products drying. With the air conditions produced by the heat pump, the drying was simulated in stationary layer, according to Thompson Model, by the computer program called SASG 5.0. Results indicate that simulation model for beans still needs some arrangements and deeper assessments.