GJ-CHART: a simple design method for partial solar heated modular polyvalent dryers

The authors have proposed a generalisation of the J-CHART method [1] for a polyvalent modular drying system obtained by multiple simulation of thermal performance of two standard configurations: without recycling the air leaving the dryer, with 50% recycling of the air leaving the dryer and mixing with the air leaving the collectors. This method, named as “GJ-CHART” is based on the use of charts or polynomial correlations which allows to determine the fraction of monthly average heating load supplied by solar energy and the fraction of monthly average economized energy as function of the two dimensionless parameters. These parameters are related to the standard collector parameters, the data of monthly average radiation, temperature and the estimates of drying loads, which by consequence, allows for a more general use. The GJ-CHART method was developed for drying 27 kg of apple slices placed in single layers on the trays of the modular dryer. The temperature and the drying air flow rate are 60°C and 0.09 ...