5 Design and Development of a Concentrated Solar …
71
Table 5.2 Variation of T with length of pipe
n
gap, x(mm)
Length, L(m)
T ( ◦ C) for ˙
m =
0.03 kg/s
T ( ◦ C) for ˙
m =
0.035 kg/s
11
9.5
2.2
9
7.6
12
7.8
2.4
9.7
8.3
13
6.3
2.6
10.5
9
14
5.1
2.8
11.3
9.7
15
4.1
3.0
12.2
10.4
Table 5.3 Receiver geometry design parameters
Parameter
Value
width of absorber, w
20 cm
Length of pipe, L
2.6 m
Outer diameter of pipe, D o
9.525 mm
Inner diameter, D i
7.747 mm
No of loops, n
13
Table 5.2 shows the variation of temperature rise with length of pipe. The length
of 2.6 m is chosen for the design as it gives a temperature rise of 10
◦ C and also
for ease of manufacturing of the serpentine receiver. The parameters of serpentine
receiver are shown in Table 5.3.
5.3 Manufacturing of CSWH
The development of the CSWH system involved the fabrication of parabolic dish,
copper tube receiver, selection of required accessories and assembling the system.
At first, mild steel strips with the required co-ordinates are forged and assembled
into a parabolic skeleton. Channels are fitted on to the skeleton and aluminium sheets
(reflectivity 0.85) are fixed on the channels with screws, forming the parabolic dish of
required depth and aperture. The receiver is made by using copper tube. A copper tube
of length 2.6 m and outer diameter 9.525 mm is cut and brazed with elbows to form the
required shape according to the design specifications. The receiver is insulated with
a pack of glass wool on the backside. A cavity is made with aluminium sheets on the
receiver to reduce the losses and increase efficiency. Cavity receiver is mounted on
to the parabolic dish with steel angles. Manual tracking mechanism is incorporated
on the parabolic dish for tracking the sun. Hose pipes of diameter 12.7 mm are used
to connect the inlet and outlet of the receiver to the reservoir tank of capacity 200 L.
An electric pump is installed for circulating the water in the system along with a seat
valve to control the mass flow rate at the inlet (Figs. 5.7 and 5.8).
71
Table 5.2 Variation of T with length of pipe
n
gap, x(mm)
Length, L(m)
T ( ◦ C) for ˙
m =
0.03 kg/s
T ( ◦ C) for ˙
m =
0.035 kg/s
11
9.5
2.2
9
7.6
12
7.8
2.4
9.7
8.3
13
6.3
2.6
10.5
9
14
5.1
2.8
11.3
9.7
15
4.1
3.0
12.2
10.4
Table 5.3 Receiver geometry design parameters
Parameter
Value
width of absorber, w
20 cm
Length of pipe, L
2.6 m
Outer diameter of pipe, D o
9.525 mm
Inner diameter, D i
7.747 mm
No of loops, n
13
Table 5.2 shows the variation of temperature rise with length of pipe. The length
of 2.6 m is chosen for the design as it gives a temperature rise of 10
◦ C and also
for ease of manufacturing of the serpentine receiver. The parameters of serpentine
receiver are shown in Table 5.3.
5.3 Manufacturing of CSWH
The development of the CSWH system involved the fabrication of parabolic dish,
copper tube receiver, selection of required accessories and assembling the system.
At first, mild steel strips with the required co-ordinates are forged and assembled
into a parabolic skeleton. Channels are fitted on to the skeleton and aluminium sheets
(reflectivity 0.85) are fixed on the channels with screws, forming the parabolic dish of
required depth and aperture. The receiver is made by using copper tube. A copper tube
of length 2.6 m and outer diameter 9.525 mm is cut and brazed with elbows to form the
required shape according to the design specifications. The receiver is insulated with
a pack of glass wool on the backside. A cavity is made with aluminium sheets on the
receiver to reduce the losses and increase efficiency. Cavity receiver is mounted on
to the parabolic dish with steel angles. Manual tracking mechanism is incorporated
on the parabolic dish for tracking the sun. Hose pipes of diameter 12.7 mm are used
to connect the inlet and outlet of the receiver to the reservoir tank of capacity 200 L.
An electric pump is installed for circulating the water in the system along with a seat
valve to control the mass flow rate at the inlet (Figs. 5.7 and 5.8).