In the present work two parabolic trough concentrator system of different rim angle and
different reflector aperture area is designed, fabricated, and evaluated, and operated for generate hot
water .There one system is 45° rim angle and next is of 90° rim angles, here reflector aperture area of
45° rim angle has operatically 20% more than 90° rim angle system, but remaining all other features
are same for both the 90° and 45° system. On operation of the system we gets nearly same efficiency
for both the system thus we observe that for all same equal features except of reflector aperture area,
the efficiency got 20+% more for 90° rim angle compare to 45° rim angle. The Supporting stand of
concentrator is made of mild steel & reflector is made of acrylic sheet with a rim angle of 45 and 90
degree and aperture area of 2.20 m square and 1.84 m square with a concentration ratio of 10.00 and
08.30. Both the receiver tube has made of aluminum metal material. The thermal performance of the
PTC was determined based on ASHRAE 93-1986 (RA 91) .The maximum instantaneous thermal
efficiency separately both system is obtained closely to 58.32% – 59.24 % range. The total cost for
each separate system is calculated Rs 4500 Indian.
5. Geometrical concentration ratio ‘C’ for tubular receive
!#
We have taken D= 0.03 m
The three parameters rim angle, aperture width and focal length are determine the cross-section
of PTC. is expressed as a function of the ratio of the aperture width to the focal length.
tan =
$%
'(
7. )
The function of the rim angle is expressed as the ratio of the aperture width to the focal length
that is = a/+,
Here is the focal length, i.e. the distance between the vertex of the parabola and the focal
point. Equation of parabola on x axis:
- ./
0
Table 1: Specifications of PTC
FABRICATION OF PTC
The PTC parts has constructed according to given below process and descriptions.
1-Frame structure for PTC system holding and support
For holding and support the receiver and reflector a frame structure of made by mild steel
Iron has assembled with use of arc welding, drilling and nut-bolt joint. The reflector support frame
portion was adjustable to horizontal axis for automatic or manual sun tracking. The single Sun
tracking and double Sun tracking structure is designs according structure frame manner.