Abstract: A solar array is provided with a first heat-transfer fluid transporting line (parabolic trough loop) for transporting a first heat transfer fluid, and at least one further heat-transfer fluid transporting line for transporting a further heat transfer fluid arranged to receive solar energy from, for example, a parabolic-trough solar array. The first heat-transfer fluid transporting line and the further heat-transfer fluid transporting line are coupled to form an overall heat-transfer fluid transporting line (for example, as a parabolic trough loop). The first heat-transfer fluid transporting line is connected to at least one main line pump for pumping the first heat transfer fluid through the heat-transfer-fluid transporting line and the further heat-transfer fluid transporting line is connected to at least one further main line pump for pumping the further heat transfer fluid through the further heat-transfer-fluid transporting line. The first and further heat-transfer fluids may be the same fluid.