variavel0=<b>Jaime Vilela de Resende</b> - jvresende@mecanica.ufu.br Universidade Federal de Uberlāndia
<b>Oscar Saul Hernadez Mendoza</b> - oscarhm@mecanica.ufu.br Universidade Federal de Uberlāndia
<b>Gleyzer Martins</b> - gmartins@mecanica.ufu.br Universidade Federal de Uberlāndia
<b>Abstract.</b> The study of the packed fruits precooling with forced air, generated in an air cycle operated by exhaust gases of internal  combustion  engines,  was  made  using  the  technique  of  full  implicit  finite  difference,  considering  the  product  as  an  infinite  slab  submitted  the non-symmetric boundary conditions of convective heat  transfer. Data obtained of the energy and mass balances, air  properties  and  performance  in  the  diverse  stages  of  the  expansion  cycle  determine  the  air  conditions  (air  flow  rates  and  temperatures) in the cooling chamber. Based in these data, the heat transfer coefficients used in the simulations are obtained from  Nusselt versus Reynolds equations and, product thermophysical properties variable with the temperature, from  adjusted polynomial  functions enclosing all the processing temperature range. This cooling system constitutes a compact system of cogeneration where  can be obtained output air temperatures  between 0 and 15oC. If fruits cooling is the unique purpose of the cogeneration system, the  program allows estimation of dynamic heat transfer behavior inside the product and determination of product residence time in the  equipment to reach the desired temperature.
<b>Keywords.</b> Fruits precooling, cogeneration, air cycle, turbomachines.