Can Hybrid Solar Systems Provide Backup for Medical Devices?

Hybrid Solar System Design for Medical Backup

A well-designed hybrid solar system with a battery bank can provide reliable backup power for critical medical devices. This system should include a critical loads panel that isolates the medical equipment from the main electrical panel, allowing it to operate independently during grid outages. The critical loads panel should be designed to prioritize the medical equipment, ensuring that it receives power even when the battery bank is low.

Battery Bank Sizing for Medical Backup

To ensure reliable backup power for medical devices, the battery bank should be sized to meet the minimum power requirements of the equipment. For example, a ventilator may require a 200-watt continuous load, while an oxygen concentrator may require a 500-watt continuous load. The battery bank should be sized to provide at least 2-3 hours of backup power at the minimum load, taking into account the depth of discharge (DOD) and the desired backup time. A typical rule of thumb is to size the battery bank for 2-3 days of backup power, assuming a 25% DOD.

Islanding and Transfer Switching

To ensure seamless transfer between grid power and backup power, the hybrid solar system should include an islanding and transfer switching system. This system allows the critical loads panel to switch to battery power during a grid outage, and then switch back to grid power when the utility supply is restored. The system should also include a transfer switch that can automatically switch between grid power and backup power, eliminating the risk of power disruptions to medical equipment.