Solar Thermal Application for Decentralized Food Baking Using Scheffler Reflector Technology

Abstract

Baking is an energy intensive unit operation. The thermal application of solar energy is getting attention in food processes by eliminating the facts of interrupted supply and fluctuated costs of nonrenewable energy sources. This study has been carried out for the design and development of solar bakery unit which comprises of a 10 m2 Scheffler reflector focusing all the beam radiations on a secondary reflector that further concentrate the beam radiations toward the heat receiver of solar bakery unit to heat up the air circulated through baking chamber employing a photovoltaic operated fan. Computational fluid dynamic (CFD)-based three-dimensional (3D) simulation was performed to analyze the design for uniform air distribution in the baking chamber. The system designed configurations gave quite good results for airflow distribution. The receiver temperature reached between 300 and 400 °C while temperature at the inlet of baking chamber was in the range of 200–230 °C, sufficient for most of the products to be baked. The maximum available solar power at receiver was calculated to be 3.46 kW having an average efficiency of 63%. A series of experiments were conducted for the baking of cakes and total energy available in baking chamber was about 3.29 kW and cake utilized 0.201 kW energy to be baked. The average value of energy utilization ratio was found to be 45%. As a base, the study would lead to the development of an appropriate and low cost solar baking units for the maximum retention of quality parameters and energy saving.

Experimental performance analysis of an improved receiver for Scheffler solar concentrator

“…In India, Scheffler concentrator has gained large popularity for community cooking and industrial heat application [25,26]. Moreover, researchers have integrated the Scheffler concentrator to the backing unit and solar dryer [27,28]. Dome type and flat surface external receiver are being used for Scheffler solar concentrator.…”

Development and Experiments on a Batch-Type Solar Roaster—An Innovative Decentralized System for Coffee Roasting

“…The Scheffler reflector design of the paraboloid lateral part that is inclined at an angle of (43.23 ± α/2), so the reflector's actual area of aperture (A c ) is calculated as A c × cos(43.23 ± α/2). For measuring the total available energy (Q a ), the direct normal irradiance (E DNI ) is multiplied by the fraction of the actual aperture area as equated below [34],…”

Development and Experimental Results of a Thermal Oil Based Roasting System for Decentralized Processing of Groundnuts

“…With the design configuration of the lateral part of a paraboloid, the frame of Scheffler concentrator is inclined at an angle of (43.23 ± α/2) degrees, therefore, the effective aperture area (A c ) of the concentrator is taken as A c × cos (43.23 ± α/2). The total input energy available (Q a ) at the face of the concentrator is the DNI measured by pyranometer (E DNI ) times this fraction of the effective aperture area and is calculated from Equation (2) [21]:…”

“…The absorbed radiation component of energy (Qap) depends upon the reflectivity of the material used (Highly reflected mirrors >90%). Therefore, the energy available after primary concentrator (Qpr) is given as [21]:…”