Desenvolvimento de uma camara frigorifica encamisada para estocagem de frutas e hortaliças

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

A jacket system for cold storage room of perishable goods was designed and its performance evaluated using electric resistances as heating load. The jacket consisted of plywood panels, 1,0 cm-thick (except a 2 cm-thick floor) treated for vapour barrier and arranged inside a conventional cold room, forming a 5 cm-duct surrounding the14 - room. Air (16.3 m3/min), cooled by the evaporator, circulated through this enclosed space The refrigeration system used R-22, an open compressor (1472 W) and an evaporator (12 m2) placed inside the jacket. Tests were performed mantaining the chamber temperature at 0°C and at 10°C, with heat load ranging from 324 to 1052 W. The relative humidity was kept higher than 99%, even under evaporator defrosting. The temperature was monitored at 43 points. Temperature differences between the air in the jacket and in the chamber ranged between 4 and 7,5°C depending on the heating load. The increase in air temperature along the jacket was 2 to 3,4°C. Two types of cold room temperature controlers were used: a) A compressor capacity control valve that delivered hot gas directly before the evaporator was able to mantain a constant temperature at expenses of a relative high hot gas flow rate, compromising the energy eficiency. b) A thermostat placed inside the cold room, acting on the compressor, promoting a periodic air temperature inside the jacket of + 7,7°C. The thermal capacitance of the wood panels damped the amplitude of the temperature oscilation by a factor of 0,3. Temperature variation found inside the chamber was ± 0,8°C. The capacity control valve increased the electric energy consumption in 75%, compared to the system that used a thermostat for temperature control.

ASSUNTO(S)

camaras frigorificas umidade refrigeração

ACESSO AO ARTIGO

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