Producing hot water can contribute significantly to a hotel's electricity consumption, particularly where large volumes are required every day. Developed in collaboration with E&ST Environmental, this project explores a scalable concentrated solar power (CSP) system for a hotel in Tanjung Balai, Indonesia, using freely available solar energy to reduce the electricity required for water heating.

The system uses reflectors to concentrate sunlight onto receivers that heat water, coupled with thermal energy storage (TES) to maintain useful temperatures over an extended period. Prototype testing successfully kept 10 litres of water at or above 40°C for nine hours, reaching a maximum temperature of 90°C. The final proposed design scales this concept to 126 modular solar-collector islands, each comprising six receivers and reflectors connected to a 60-litre TES unit, with two central hot-water storage tanks serving the hotel.

Designed to meet the hotel's demand for water at 40–45°C, the proposed system demonstrates how concentrated solar energy and thermal storage can provide a reliable and scalable alternative for hot-water production. The project estimates that its implementation could reduce electricity costs by approximately 10%, demonstrating the potential of renewable thermal-energy technologies to make everyday building operations more sustainable and affordable.