Solar Collector - Flat Plate Anaylsis

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NATIONAL INSTITUTE OF TECHNOLOGY

DEPARTMENT OF MECHANICAL ENGINEERING

MAJOR PROJECT REPORT - PART 1 (7TH SEMESTER END EVALUATION)

DESIGN OF LOW COST SOLAR DRYER FOR FISH DRYING

UNDER THE GUIDANCE OF: Dr. T.P. ASHOK BABU SUBMITTED BY:ASHWATHI SHENOI (08M106) HARSHA GOPARAJU (08M117) SHARATH N YALE (08M141) SURESH NEHRA (08M151) VIJAY KUMAR (08M160)

SUBMITTED ON: 17th November 2011

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ContentsACKNOWLEDGEMENT ................................................................................................................ 1 OBJECTIVES ................................................................................................................................ 2 CHAPTER 01: INTRODUCTION .................................................................................................... 3 CHAPTER 02: LITERATURE SURVEY ............................................................................................ 5 PATENTS REVIEWED ............................................................................................................... 5 DATA SURVEY AND COLLECTION............................................................................................ 8 Solar Irradiance data........................................................................................................... 8 Food related data ............................................................................................................... 9 PERFORMANCE PARAMETERS COMMONLY CONSIDERED FOR EVALUATION .................... 10 CONCLUSIONS: ..................................................................................................................... 11 CHAPTER 03: SOLAR DRYER - WORKING PRINCIPLES .............................................................. 12 CHAPTER 04: SOLAR FLAT PLATE COLLECTOR ......................................................................... 15 Introduction ...................................................................................................................... 15 Absorber Plate .................................................................................................................. 15 Cover Sheets ..................................................................................................................... 17 Collector Performance...................................................................................................... 18 HEAT ENERGY BALANCE ....................................................................................................... 19 CHAPTER 05: SOLAR DRYER DESIGN ........................................................................................ 22 Design Procedure.............................................................................................................. 22 Equations used for design of dryer................................................................................... 22 MATLAB PROGRAM ................................................................................................................. 25 APPENDIX A: MATLAB Program Results Optimum Result .................................................... 26 APPENDIX B: Calculation of Collector area for above conditions ............................................ 27 APPENDIX C: Materials List ...................................................................................................... 28 APPENDIX D: PROJECT TIME-LINE ............................................................................................ 29 REFERENCES: ............................................................................................................................ 30

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ACKNOWLEDGEMENTWe would like express our sincere gratitude to Dr. T.P. Ashok Babu whose valuable guidance greatly assisted us in our task.

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OBJECTIVESThe aim of the project is to design, build and test the working of a low cost solar dryer (mixed type) for use in fish drying along the coasts of Mangalore. The objectives are as follows: To study the various physical and thermal parameters that influences the performance of the solar dryer. Write a program that will help us perform number of iterations to see how changing various parameters affect the dryer efficiency and collector area required.

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CHAPTER 01: INTRODUCTIONOpen air sun drying is still the most common method used to preserve agricultural crop and sea food. The marine fish production potential of Karnataka is estimated at around 4.25 lakh M.T. per annum. In Karnataka, mackerals, sardines, anchovics and other elupeids form the dominent pelagic fishing while catfishes, Sciaenids, Perches, sharks and rays etc. constitute the deep sea fishing. Soles, and prawns form the major demersal fishery.

However, being a highly perishable food product, fish can be stored for long periods of time only by proper refrigeration or drying. Since most of the fishermen living at the coastal belt are below the poverty line therefore refrigeration is distinct dream to them. The only alternative available is drying in the open air, in an uncontrolled and unhygienic environment. To reduce the processing losses during the drying and to retain the quality of dried product, it is necessary to dry the fish in the close chamber with preventing product from dust, insect, larva, birds and animal.

The coastal region of Karnataka is blessed with ample sunlight all the year round. There is tremendous potential for utilization of this solar energy. It is therefore expected that the design of a simple and economical solar dryer could contribute greatly in solving the local fishermen's problem.

Solar dryers may be classified according to the mode of air flow as natural convection and forced convection dryers. Natural convection dryers do not require a fan to blow the air through the dryer. Solar drying may also be classified into direct, indirect and mixed-modes. In direct solar dryers the air heater contains the materials and solar energy passes through a transparent cover and is absorbed by the materials. Essentially, the heat required for drying is provided by radiation to the upper layers and subsequent conduction into the material bed. In indirect dryers, solar energy is collected in a separate solar collector (air heater) and the heated air then passes through the material bed, while in the mixed-mode type of dryer, the heated air from a separate solar collector is passed through a material bed and at the same time, the drying cabinet or chamber absorbs solar energy directly through the transparent walls or roof.

Hence we will be focusing our efforts on designing and fabricating a simple direct natural convention dryer for Mangalore. The use of solar technology has often been suggested for

4 the dried fruit industry both to reduce energy costs and economically speed up drying, which would be beneficial to final quality, dried grapes, okra, tomato and onion using solar energy. They concluded that drying time reduced significantly resulting in a higher product quality in terms of color and reconstitution properties. They also believe that as compared to oil or gas heated dryers, solar drying facilities are economical for small holders, especially under favorable meteorological conditions.

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CHAPTER 02: LITERATURE SURVEYAfter extensive survey of literature and collection of papers we have seen that it would be most economical to first develop a prototype of a simple cabinet chamber type of solar dryer, as the more complex designs would increase the cost quite considerably. Once we have accomplished the successful working of a basic design prototype, we would like to look at modifications to the design, which can improve performance and reduce costs further.

PATENTS REVIEWEDThe following paragraphs describe in brief the various patents that were surveyed, pertaining to drying technology, solar dryers and food preservation.

PATENT TITLE: Drying Method and Apparatus for Drying Prunes, Fish, Brewers Grain, Shelled Corn and the like. PATENT NUMBER:

US4326341DESCRIPTION: Developed a method and apparatus for drying moisture-containing material by use of a vacuum tank. The tank is partially filled with cold liquid, such as water, and the material to be dried is supported in the tank above the liquid surface. Surface condensing means are located inside the tank. Air is first evacuated from the chamber by first filling the tank completely with liquid. Then by means of a pumping mechanism, the liquid and the condensate are removed from the chamber, due to drop in pressure the moisture from the material is also evaporated and condensed on the provided means.

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PATENT TITLE: Convection Powered Solar Food Dryer PATENT NUMBER:

US4501074DESCRIPTION: Developed a solar powered food dryer that may be used indoors. Convection column is used to produce a draft of air. By means of this draft, air is drawn from a solar collector through a food drying chamber in such a way that the hot air from the collector is drawn over the food in the drying chamber and hot air ducting of the air stream provides a means of remotely locating the drying chamber to a sanitary and convenient place while leaving both the air heater and the draft generating convection column in a place exposed to solar radiation.

PATENT TITLE: Process of Dehydrating Biological Products PATENT NUMBER:

US6068874DESCRIPTION: Makes use of a closed system for dehydration using a heat exchanger and dehydration chamber connected by appropriate conduits. Provision of blowers as controls for the system parameters of the process. Advantages of the design include, retention of aroma and natural flavor of the original food, and ease of transportation unlike refrigerated foods etc. Main disadvantage is the high cost of equipment and un