Experimental Performance Analysis Of Multi Electric Mitad Injera Baking System

Abstract

In Ethiopia, Single Clay Electric Injera Mitad Which Uses 3.5 Kw Electric Power Is Extensively Used For Baking Injera By Almost All Urban Households And It Is Reported To Have 50 ?�? 60%Energy Loss From Which 35.08% Is Bottom Loss. This Single Clay Mitad Is Also Time And Energy Consuming For Mass Production. The Major Objective Of This Thesis Is To Design And Experimentally Investigate The Performance Of Locally Constructed Multi Mitad Injera Baking Electric System Consisting Of Four Mitads Arranged Vertically In A Single Column Stand But Can Be Retracted Horizontally In And Out Of The Stand To Do The Baking Processes. Numerical Simulation And Experimental Performance Investigations Were Done To Study The Performance Of Each Mitads And When All The Multi Mitad Were Operated Together. Initial Heating Up Time, Cyclic Injera Baking Time, Power Consumption, Heat Losses Of The System, Energy Efficiency, And Effects Of Mitad Gaps Variation Between Consecutive Mitads And Varying Power Input Were Studied Experimentally And Numerically During The Baking Test (With Injera And Ambasha Baking) And No-Load Test (No Batter As Load) Were Studied With And Without Lid Cover Cases Of Operation. The Numerical Performance Was Studied By Deriving Governing Equation Using Conservation Of Energy Equation And Solving The Resulting Nonlinear Coupled Algebraic-Ordinary Differential Equation Using Numerical Iteration Solution Scheme For Simulating Closed Mitad Temperature Responses At Three Different Power Inputs. Experimental Performance Test Was Conducted Under Open And Closed Baking Doors Within Constant Power Source. Good Agreement Was Also Observed Between The Numerical And Experimental Results. The Numerical Result Showed That The Temperature For Mitads 1, 2, 3, And 4 At 11 Minutes Of Run Were Found To Be 194,238,242 And 217??? Respectively. From The Experimental Studies Conducted, It Was Observed That The Temperature Distribution Of The Mitad Is Uniform And The Use Of Lid Cover On Each Mitad Reduce The Heating Up Time By About 1 Minute Compared To Results Obtained Without Lid Cover. The Average Time It Takes To Bake Each Injera Was FoundTo Be About 90 Seconds With 40 Seconds Idle Time Between Successive Injera. The Overall Efficiency Of Multi Mitad Was Found To Be 85.3%. In The Present Multi Mitad Injera Baking System, Side Loss Contributes About 6.44% Of Total Loss Due To Larger Surface Area Than Both The Top And Bottom Of The System, And The System Can Also Save Time Consumption For Injera Baking For Instance It Takes 20 Minutes To Bake 20 Injera With The Present System, Whereas The Conventional System Takes 78 Minutes.