Panels Collector

Collector Panels

There are two main types of collector panels for solar water heating systems: flat plate panels and vacuum tube panels.

A flat plate panel is similar to a skylight. It absorbs sunlight and transfers the heat to the water or liquid flowing through the collector panel. The common size for a house is one to three panels, between 2.5 square meters and 6 square meters in total.

An evacuated tube panel consists of a series of glass tubes (between 1.5 and 2 m long) inclined up and down longitudinally across the roof.

In New Zealand's temperate climate, both panel types are equally effective.

Detail of a flat plate panel (image from EECA).

Detail of a vacuum tube with heat pipe (image from EECA).

The hot water cylinder can be part of the system on the roof, or it can be mounted separately – in another part of the house.

You can use a conventional hot water cylinder or a specialist solar water heating cylinder. The main difference is that specialist cylinders are larger and they are specially designed to maximize the use of solar energy. If you opt for a specialist cylinder, the system is likely to perform better. However, it is possible to achieve reasonable performance with a conventional cylinder through effective system design.

If you choose to use a conventional cylinder, you need a controller for supplemental heating.

Conventional hot water cylinders in homes are usually 180 liters or less. This storage capacity is usually too small for a solar water heater to achieve optimal performance for a family of three or more people. Performance can be increased with the use of a controller for supplemental heating.

If you are planning to get a system that includes a cylinder, carefully check the price – a cheaper price may mean cylinder components and others are not included.