DESIGN AND FABRICATION OF SOLAR BIOMASS DRYER USING FORCED CONVECTION PROJECT REFERENCE NO.: 38S INTRODUCTION

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1 DESIGN AND FABRICATION OF SOLAR BIOMASS DRYER USING FORCED CONVECTION PROJECT REFERENCE NO.: 38S0698 COLLEGE : ANGADI INSTITUTE OF TECHNOLOGY AND MANAGEMENT, BELAGAVI BRANCH : MECHANICAL ENGINEERING GUIDE : PROF. KRISHNAKUMAR A. JERE STUDENTS : MR. MOIN M. KAZI MR. MUDASSARM. KAZI MR. DASTGEERASABB. TAMBOLI MR. MAHAMMAD IQBAL HAWALDAR 1- INTRODUCTION Dehydration is most popular technique used for preservation of agricultural products including fruits even fish and meal. Drying techniques include open air drying, fuel fired drying, electrical drying and solar drying. The use of open air drying is cheap and most popular method used through the world but results in contamination of food, nutritional deterioration and consumes more time when compared to other dryers. Fuel fired dryer are totally dependent on conventional fossil fuels, firewood or coal which may cause pollution and contribute to deforestation and Cause environmental degradation. Electrical drying however consumes less time to dehydrate the crops and does not cause any of the pollution, but availability of electricity in rural areas where much of the drying of eatables takes place is still less. Where as in contrast to all the above dryers solar dryer solar dryer is not only environmentally friendly but can be used both in urban and rural areas for domestic and commercial purpose and is much more simple compared to other forms of dryers. Solar dryers require much lesser time compared to other forms of dryers and it provide higher drying temperatures as drying takes place in an enclosed cabinet. Various drying techniques are employed for drying of different food products every technique has its own advantages and disadvantages. Choosing of proper technique is necessary to preserve these perishable food products. The solar and biomass hybrid dryer is one such dryer which has achieved some level of acceptance. One of the important disadvantage of this dryer is that it cannot be used without any backup heater during night times and cloudy days. Introducing backup heater makes the dryer operational even beyond sunshine hours. In many parts of the world there is growing awareness that renewable energy has an important role to play in extending technology to farmers in developing countries so that their productivity is increased. Even most of the agricultural community is concentrated in rural areas where there is a scarcity of electricity, so solar thermal technology is one such technology that is rapidly gaining acceptance as an energy saving method in agricultural applications. It is preferred as one of the best among various other alternative energy sources- It is abundant inexhaustible and non-polluting and principles of operation of various solar applications are simple. Even the growing awareness towards environmental pollution, deforestation global warming have paved a way for this solar technology. There is also promising future for this solar dryer as most of the solar powered appliances like solar illuminations, solar water heater, solar pumps etc. have firmly registered their presence in the market so the future for this emerging technology is very good. Solar air heater is a device that is used to heat air by using solar energy and use this air for various applications like crop drying space heating. Drying process plays an important role in preservation of agricultural products. It is defined as process of moisture removal due to simultaneous heat and mass transfer. Mainly two types of moisture are present in food items they are chemically bound water and physically held water. In drying process it is only physically held water that is removed from the food product. The most important reason for popularity of dried food products is its longer life, easy storage and reduction in volume.

2 The product can be further improved by various processes. The application of this dryer in developing countries can reduce post-harvest losses and is economical because of low cost and does not make use of electricity thus improve the food availability in those countries. The product can be further improved by various processes. The application of this dryer in developing countries can reduce post-harvest losses and is economical because of low cost and does not make use of electricity thus improve the food availability in those countries 2-AIM AND OBJECTIVES The main aim of our project is to design and fabricate solar powered biomass dryer with biomass backup burner. The main objectives of our project are: To show advantages of drying by Solar and biomass integrated dryer over other forms of drying process. To show the temperature variation during drying process. 3-JUSTIFICATION We often observe that most of food products are lost only because of lack of effective preserving methods and infrastructure. Even the food products spoil during transportation and storage. The main reason for food products to turn useless is moisture. This makes it very much necessary to maintain only minimum or required level of moisture and remove excess of it from the food products. The most popular method used for removing this moisture in various parts of world is open air drying as this method is free of cost and does not require any special method. But during open air drying there is risk of crops being attacked by insects even the ultraviolet rays may deteriorate the nutritional level in the crops. This makes the food unhygienic. So the solar powered biomass backup dryer provides solution for most of the problems faced during open air drying. This also compensates upon various drawbacks in open air drying and other forms of drying. 4-OPERATION OF DRYER 4(a)solar mode of operation Firstly solar dryer is placed in such a way that the collector is going to face to the Northern- west side so that the collector is exposed to sunlight for maximum time during it operation in solar mode. When sunlight is going to be incident on the collector by passing through fibre glazing placed over the black painted aluminum plate is going to absorb the solar radiation and the temperature of the collector is going to increase. Airis sent forcibly with the help of air blower. The air which enters the collector in such a way is going to come in contact with hot aluminum plate. As the temperature of the aluminum plate is greater than that of the temperature of the air the heat transfer is going take place from hot aluminum plate to the cold air. This process of heat transfer is going to increase the temperature of the air. The property of air such that when the temperature of the air increases the density of the air is going to decrease and thus the weight of the air is also going to decreases. Thus the lighter air is going to rise to the higher levels. The collector is placed inclined to the ground level and other end of the collector is connected to the drying chamber the hot air is thus going to enter the drying chamber as the collector is inclined. When the hot air which is less dense is going o rise through the drying chamber as it enter the drying chamber. Three trays are placed in the drying chamber, these trays are provided with holes with allow the air to pass from the bottom side of the tray to the top side f the try. Material to be dried is been placed on these trays. The hot air in the drying chamber is going to come in contact with the material surface thus allowing the moisture content in the material to evaporate. As the water is evaporated from the material the material is going to be dehydrate i.e., it is going to lose the water present in it.

3 Thus the air from the atmosphere is going to take away the moisture from the material and is going to dry it. Thus the drying operation is carried out through the day without any interruption. The drying of material takes place without any pollution and without spending any money on electricity and with maintenance which is almost equal to nil. 4(b)BIOMASS MODE OF OPERATION As solar mode of operation of dryer is going to work only during presence of bright sunlight and during the day time only. During the over shed conditions or during rainy season the solar mode drying is interrupted. Thus biomass mode of drying is included in the dryer. The biomass mode of drying is going to serve as an alternative method to carry out drying process. In biomass mode of drying biomass chamber comes into picture. Fuels like coal, firewood are going to act as the source of energy for the dryer. Coal or firewood is going to be fed to the dryer through the door which is been provided at the bottom of the drying chamber. Through the biomass mode if drying serves as alternate mode of drying of food. It is not environmental friendly as the fuel burnt is going to liberate flue gases which are harmful to the atmosphere. The firewood used is also going to increase deforestation process. 5-TESTING OF DRYER 5(a) Solar mode testing. Test of dryer was been conducted by placing 95gms of potato chips on first tray and the dryer was been operated in solar mode. The potato chipsloss of 60gms of water in a 1 hours of drying process with average operation temperature of 42 o c thought the 1hours for solar mode drying assisted by biomass mode of drying thus giving better results than open air drying. Figure 5(a)-Potato Chips 5(b) Biomass mode testing. Test of dryer was been conducted by placing 35gms of potato chips on first tray and the dryer was been operated in Biomass mode. The potato chips loss of 19gms of water in 0.5 hours of drying process with average operation temperature of 55 o c thought the 0.5 hours for biomass mode drying assisted by solar mode of drying thus giving better results than open air drying. Biomass mode provided higher temperatures for drying compared to solar mode of operation. During solar mode of operation temperature of about 55 o c was been achieved. Following figures shows the dried potato chips.

4 Figure 5(b)-Potato Chips 6-RESULTS AND DISCUSSIONS The dryer was been placed under sunlight on 18 th of May 2015 for obtaining results by solar mode of operation and by burning coal during biomass mode of operation. 6(a) SOLAR MODE OF OPERATION Temperature variation during different times of day was been noted down in different parts of dryer during 6hrs of experiment by using thermometer and the following graph was been plotted by using these readings. Figure 4(a) - Temperature variation in solar mode of operation During solar mode operation it is been noticed that higher temperature were gained for drying process when compared to atmospheric temperature available for open air drying. Temperature of collector air was about (20-25) c greater than atmospheric temperature. The temperature of drying chamber was about (15-18) c greater than atmospheric temperature. These results show that the drying process can be carried out at higher rate in this type of dryer thus justifying this idea of drying. 6(b) Biomass mode of operation

5 Dryer was been operated in biomass mode by burning wood in biomass chamber between time 10am-10.15am. Simultaneously temperature variation in the dryer was been noted down. Readings were been recorded for every 3 min and following graph was been plotted. Figure 4(b) - Temperature variation in biomass mode of operation During biomass mode of operation it is been noticed that higher temperatures were gained for drying process when compared to temperature obtained during solar mode of operation. Temperature of drying chamber was about (10-30) c greater than atmospheric temperature. It was been noticed that higher were obtained within less time. These results show that the drying process can be carried out at higher rates in biomass mode of operation when compared to solar mode of operation. 7-SCOPE OF FUTURE WORK Solar-biomass dryer can find very good applications in future. As preservations of food is an important requirement of any country solar biomass dryer can be developed as good alternatives when compared to other forms of drying. As the demand for food grains has increased the continuous supply of goods quality product is very much necessary. In such condition solar-biomass dryer can fulfil the needful Many improvements can be done in the present models of solar-biomass dryer thus increasing the effectiveness of the dryer. The chimney can be replaced by exhaust fans which help in improving the circulation of air. Heater which runs on solar energy can be used for supplying energy for heating the air during night times which is going to make the dryer 100% environmental friendly. Collector can be applied with plating like copper black which helps in absorbing good quality of heat for solar mode of operation. 8-CONCLUSION Thus the solar-biomass dryer designed is simple in construction and cost effective. The solar biomass dryer performs the drying process without causing any pollution. The solar biomass dryer is more effective and consumes less time when compared to open air drying. The solar mode of operation of the dryer requires no labour to operate. The maintenance required is also very less. The solar-biomass dryer can be used even in the absence of sunlight. Thus the drying process can be continuously carried even during night times.