DESIGN AND EXPERIMENT OF PARABOLIC TROUGH COLLECTOR WITH NORTH-SOUTH ORIENTATION

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1 DESIGN AND EXPERIMENT OF PARABOLIC TROUGH COLLECTOR WITH NORTH-SOUTH ORIENTATION Mr. Shailesh Prajapati 1 and Mr. Dip Shah 2 1,2 Assistant Proffesor,Mechanical Enginnering Department,Institute of Technolgy and management universe,vadodara Abstract--Solar energy is continuous on earth & which is renewable energy sources. Sun throw rays in form of radiation. We can use this solar radiation & convert solar energy in different form of energy by using different methods & technology. Concentrating solar power is one of them. Concentrating solar power (CSP) is a renewable generation technology that uses mirrors or lenses to concentrate the sun s rays to heat a fluid, e.g., water, which produces steam to drive turbines. CSP differs from solar photovoltaic (PV) technology, which directly converts the sun s ultraviolet radiation to electricity using semiconductors.csp is a proven technology with more than 350 megawatts (MW) of installed capacity operating commercially in the Mojave Desert since the 1980s and several smaller new plants brought on line since The current worldwide installed capacity is more than 500 MW. CSP technology uses solar energy & which is not affect the environment & not polluting atmosphere, also reducing effect of global warming etc.csp includes solar chimney, power tower, solar dish & parabolic trough. Parabolic trough technology is most commonly use of them now a days. Parabolic trough can be used for power generation, heating & cooling. The collection and concentration of solar thermal energy on the object can be done with the help of Parabolic Trough Collector (PTC) for the temperature range o C. The study of literature review reveals that much work is available pertaining to design and performance of Parabolic Trough solar collector Keywords-- solar radiation, parabolic trough collector, concentration ratio, focal point, thermal efficiency. I. INTRODUCTION Renewable energy sources are sources that are continuously replenished by natural processes. For example, solar energy, wind energy, bio-energy - bio-fuels grown sustain ably), hydropower etc., are some of the examples of renewable energy sources A renewable energy system converts the energy found in sunlight, wind, falling-water, sea-waves, geothermal heat, or biomass into a form, we can use such as heat or electricity. Most of the renewable energy comes either directly or indirectly from sun and wind and can never be exhausted, and therefore they are called renewable. There are different thermal applications for using solar energy available through radiation and convert it into useful heat energy or Electric Power.Parbolic trough collector, Fresnel reflector, central receiver system,paraboloidal Dish collector etc. are some of the applications. A conventional parabolic collector can be utilised to collect solar radiation and further can be utilized convert it in to useful heat energy. Parabolic trough collector having absorber which is located at the focal point of reflecting surface so all the reflected rays fall on the absorbing surface. The absorber surface covered with a glass to reduce the losses from the absorbing surface. A solar energy collector has a sun-facing surface and when irradiated by the solar irradiance gets heated up. The heat is then transferred partly to a working fluid in contact with the absorber. To reduce the heat losses to the surrounding and to make it work at optimum efficiency, a glass sheet covers the absorbing surface. However, losses due to convection and radiation cannot be eliminated totally. DOI: /IJMTER N0ZDU 134

2 1.1 Solar Energy Collectors A solar collector is a device for collecting solar radiation and it transfers the energy to a fluid passing in contact with it. Utilization of solar energy requires solar collectors. These are general of two types: (i) Non concentrating or flat plate type solar collector. (ii) Concentrating (focusing) type solar collector. (CSP) Concentrating/Focusing collector is a device to collect solar energy with high intensity of solar radiation on the energy absorbing surface. Such collectors generally use optical system in the form of reflectors or refractors Types of concentrating collectors: (a) Parabolic trough collector (P.T.C) (b) Mirror strip reflector (c) Fresnel lens collector (d) Flat plate collector with adjustable mirrors (e) Compound parabolic concentrator (C.P.C.). II. PARABOLIC TROUGH COLLECTOR It is a principle of geometry that an aluminum parabolic reflector pointed at the sun will reflect parallel rays of light to a focal point of the parabola. A parabolic trough is a one-dimensional parabola that focuses solar energy onto a line. Physically, this line is a pipe with flowing liquid inside that absorbs the heat transmitted through the pipe wall and delivers it to the thermal load. Figure1.Parabolic trough All rights Reserved 135

3 2.1 DESIGN The parabola is an intriguing geometric shape with important practical uses including concentrating sunlight. The curve of a parabola is such that light travelling parallel to the axis of a parabolic mirror will reflect to a single focal point from any place along the curve. Because the sun is so far away, all light coming directly (excludes diffuse) from it is essentially parallel, so if the parabola is facing the sun, the sunlight is concentrated at the focal point. A parabolic trough extends the parabolic shape to three dimensions along a single direction, creating a focal line along which the absorber tube is run. The equation of the parabola, in terms of the coordinate system shown, is y² = 4fx Figure 2.1 Geometry of Parabola 2.3 INPUT DATA Figure 2.2 Line Diagram for Experimental setup for PTC LENGTH OF PARABOLA (L) 1220 meter WIDTH OF PARABOLA (W) 760 meter COLLECTING AREA (AC) meter RIM ANGLE (θ R =ϕ) 91.81º ABSORBING FLUID WATER The angle ϕ is the rim angle, described by AFB, and is given All rights Reserved 136

4 f 8 a f 1 1 tan 8 a a sin tan sin 2 f 2r a f 16 1 a (Where rim angle ( ) = , r = a/2 = absorber area = m 2 ) f =0.1551meter For concentration ratio the equation is ( a D) C. R D C.R = (760-16)/(50.266) C.R = DERIVED DATA: FOCAL LENGTH 155 mm PARABOLA HEIGHT mm DIAMETER OF RECEIVER TUBE 16 mm CONCENTRATION RATIO NORTH-SOUTH POSITION III. OBSERVATION Sr.No: Time Temperature Time for 1 Solar Wind IST litre Fluid radiation Speed T 0 inlet C T 0 outlet C T ambient C flow (sec) (I) w/m 2 m/s 1. 10: : : : SR.NO. 1 1 a m (kg/sec) T 0 C Qi=I*A W Qo=mcp T W 10:00 AM T/I m 2 /W η thermal =Qo/Qi η thermal (%) r IV. CALCULATION 4.1 Heat Input The heat input to the parabolic trough solar collector can be calculated by considering the solar radiation flux (I) on the aperture area of the collector (A). Aperture area of the collector (A) = m 2 Q i = I x A, W = 690 x = 640 All rights Reserved 137

5 4.2 Heat Output Heat output from the parabolic trough collector can be calculated by considering the mass flow rate of water, temperature difference and specific heat of Water. Q o = m x c p x (T o T i ) = x 4187 x 2 = 109 W 4.3Thermal efficiency η thermal = Q o /Q i = 109/640 = η thermal = 17 % V. COMPARISON OF FLAT PLATE COLLECTOR AND PARABOLIC TROUGH VI.RESULTS AND DISCUSSION Above graphs clearly shows that temperature rise is higher in north-south orientation as compared to east-west orientation of parabolic trough. Rise in efficiency with time is higher in to north-south orientation as compared to east-west orientation. NORTH-SOUTH orientation is more suitable for higher temperature rise & for higher efficiency VII.CONCLUSION Design and development of Parabolic Trough Collector and subsequent experimental work carried out on this setup during the course of this work leads to the following clear conclusions. Initially the thermal efficiency is increasing with fluid temperature. After the fluid All rights Reserved 138

6 around 45 C to 49 C, the thermal efficiency again decreases. This is due to higher convection losses at more temperature difference between fluid and ambient. The maximum thermal efficiency is ranging in between 20 to 25%.The temperature gain is higher in north-south position as compared to east-west position of the parabolic trough solar collector.due to small aperture area of solar collector heat loss & optical losses are more & also owing to manual tracking the efficiency of the collector decreases. Efficiency of parabolic trough is decreasing due to heat losses & leakages.thermal efficiency parabolic trough collector can be increased by using automatic solar tracking mechanism & by proper designing. REFERENCES [1] Thesis on DESIGN, DEVELOPMENT AND TESTING OF PARABOLIC TROUGH SOLAR COLLECTOR BY Mr. Prakash R Mistri [2] Non-Conventional Energy Sources by G.D Rai [3] Solar Energy Engineering - Processes and Systems by Soteris kalogirou Cyprus University of Technology [4] Solar radiant energy over India by Ministry of new & renewable energy, Government of All rights Reserved 139