Table 2.

Design matrix and responses.

Experimental Run	Wrec (mm)	Acceptance half-angle (°)	Concentration ratio	Wapr (mm)	CPC Height (H) (mm)
1	0	0	2.00	312.00	405.30
2	0	−1	2.92	456.11	840.88
3	0	0	2.00	312.00	405.30
4	+1	0	2.00	624.00	810.60
5	−1	−1	2.92	228.06	420.44
6	0	0	2.00	312.00	405.30
7	+1	+1	1.56	485.38	475.14
8	0	0	2.00	312.00	405.30
9	0	0	2.00	312.00	405.30
10	0	+1	1.56	242.69	237.57
11	−1	0	2.00	156.00	202.65
12	+1	−1	2.92	912.23	1681.77
13	−1	+1	1.56	121.35	118.78