Inter Solar Systems [P] Ltd. Offers Solar Distillation System. Inter Solar Systems [P] Ltd. Is an ISO 9001:2000 registered company. Inter Solar Systems [P] Ltd. Supplies ISI marked solar energy products. Solar Distillation System is used for water purification, and sunlight is one of several forms of heat energy that can be used to power that process. Solar Distillation System is relatively inexpensive, low-technology systems, especially useful where the need for small plants exists.