maximum operating temperature of 102 C, which is much higher than the operating temperatures of the solar tanks. For this investigation, lamina elastic properties were used to obtain the effective isotropic properties listed in Table 2. The design variables which were used to complete the design of the test materials were the inner jacket laminate thickness and composite material lay-up. The capacity provided by each lay-up was assessed by comparing its strength with the von Mises Stress. The final design was based on a 090, 45 lay-up of the glass fibre/polyester laminate, which has strength of 80,000 psi (551 MPa)