Domestic Solar Panel Hot Water Heating Systems
Harpenden, St.Albans, Hemel Hempstead, Welwyn Garden City, Watford and Tring

How the System Works

A typical domestic solar panel hot water heating system uses a dual-coil cylinder, meaning it is fed by both a conventional boiler (or other heat source) and the solar panels. Both systems work together to heat the household hot water. The solar panel hot water system has its own pump, expansion vessel, pressure relief valve, air vent and controller.

The energy in the sun’s rays is collected by the solar panels and the heat is transferred into a fluid-filled pipe connected to the lower coil of the dual-coil hot water storage cylinder. The heat absorbing fluid is a glycol and water mix that won’t freeze in cold weather. Heat is created by a pump circulating the liquid to the coil in the hot water cylinder, and this heats the water. The solar heating system is equipped with a simple controller to regulate the flow of energy from the panels to the storage cylinder, which will maximise the use of the available free solar energy.

The conventional boiler tops up the heat provided by the solar hot water heating system as required and continues to supply hot water for the central heating system.

Effective Positioning of Solar Panels

For maximum efficiency, the solar panels should be installed at a 45˚ degree angle on a southeast to southwest facing roof (or other suitable surface) and should not be overshadowed by trees or other obstructions. East and North facing directions should be avoided.

Hot Water Storage Cylinders

The solar panels and your conventional heating system both work together to heat your hot water within the dual-coil storage cylinder, which usually replaces your existing one.

To make the most of summer sunlight and the higher potential solar energy gains, we recommend that a two-panel solar hot water system should ideally be combined with a 300 litre cylinder. If this is not possible, a storage cylinder of at least 200 litres storage is used.