Choosing the Right Solar Water Heating System: Zenith

Article overview

Zenith publishes three distinct solar water-heating configurations: thermosyphon, forced circulation and drain back. The appropriate system depends on hot-water demand, collector and tank position, pumping requirements, electrical backup, water conditions and service access.

Thermosyphon solar water heating

A thermosyphon system uses natural circulation between the collector and storage tank, so a circulation pump is not required. Zenith’s published thermosyphon range covers 150, 200 and 300 litre configurations with flat-plate collectors and electric backup.

• Natural circulation
• 150–300 L published range
• Flat-plate collector
• Electric backup

Forced circulation solar water heating

A forced circulation system uses a pump and controls to move heat between the collectors and storage tank. Zenith documents an electric backup element, U-tube heat exchanger, magnesium anode, temperature-and-pressure relief valve and service access.

• Pumped circulation
• U-tube heat exchanger
• Electric backup
• Service access and protection components

Drain back solar water heating

A drain back system returns fluid from the collector loop to storage when solar heating stops. Zenith’s dedicated page records the collector construction and product-specific EN 12975-2, Solar Keymark and CE references.

• Drain-back configuration
• Product-specific certification references
• High-temperature collector materials

Which system fits the project?

Start with the building’s daily and peak hot-water demand, available roof and plant-room layout, collector and tank position, backup-heating requirement, water conditions and service clearance. Use the dedicated system pages for specifications and ask Zenith to review the site requirement before selection.