Studies on the Design and Construction of Hydrocooler for Fruits and Vegetables

Abstract

A commercial prototype hydrocooler was designed and constructed by the Food and Agricultural Engineering Laboratory, University of Kagoshima, Kagoshima-shi, Japan.
This report presents the fundamental design features and cooling capacity of the prototype.
The prototype can be operated as immersion or flood cooling system.
In the immersion-type cooling system, chilled water in the cooling tank is circulated by an agitating propeleer, ce Products under the conveyer are immersed in the chilled water from inlet to outlet.
In the flood-type, chilled water is pumped to a perforated flood-pan, which showers the chilled water to products on the conveyer in the cooling tunnel,
1) When a 12.7mmφ perforated flood-pan was used, it could most efficiently cool products which were fed at a flow-rate of 0.65m³/min. per square meter of conveyer, under the conditions studied.
2) It is not efficient to cool commodities contained in wire-band-crates.
3) Several graphs were made for cooling time of products. Figures 10 and 11 could be used to predict the time required to achive temperature reduction of carrots and radishes by the prototype, when initial temperature of products and chilled water temperature were given.
4) The prototype has a capacity to cool 700-800kg/hr of carrots or 540-620kg/hr of radishes from 20°C to 5°C, with 1.0°C chilled water.