Solar hot water heating can achieve savings of up to 75%!

Buildings in New Zealand are exposed annually to 20 or 30 times more energy from the sun than they consume in electricity and gas. New Zealand has a world class solar resource.

On the average, more than 40% of domestic electricity is used for heating water. Solar hot water can achieve savings of up to 75% of hot water usage in the winter and up to 98% in the summer. Solar heating systems are based on the same simple, yet extremely effective principles.

The solar panels collect and concentrate the energy from the sun. The thermostat controller senses the temperature in the panel and hot water cylinder to initiate a super quiet pump when optimum conditions are met. Hot water from the panel is transferred to the cylinder.

A digital read auf, which can be located anywhere in the house, monitors and visually displays all the information for the different operation modes - keeping you informed of exactly what is happening with your system.

Types Of Solar Heating Systems

The type of solar hot water system chosen for a particular installation will depend on a number of factors such as cost, required temperature and quantity of hot water, ease of installation and even the structural integrity of the building. lt is the requirement for different temperatures that cause the greatest variation. Typical temperature categories are given below.

Low Temperature Systems

These are usually unglazed systems (i.e. not having a transparent cover) which only raise the temperature of the fluid passing through them by a few degrees, up to a maximum of about 40 °C. These systems use collectors made of UV-resistant plastic tubing laid directly an the roof. The typical application is solar pool heating.

Medium Temperature Systems

These are systems which operate between 40°C and 200°C, and typically in the 40°C to 100°C range suitable for domestic and commercial hot water needs. Glazed, fiat plate collector systems are the most frequently used in New Zealand and Australia. Concentrating sun tracking systems, evacuated tube collectors and solar assisted heat pump and gas systems have also been used.

High Temperature Systems

To achieve temperatures above 200°C, radiation concentrating systems are used. Concentrating systems must also incorporate sun tracking to maintain the maximum radiation availability to the collector at every moment of the day. These systems are generally used to generate steam for industrial processes or to generate electricity via a conventional steam turbine-generator. Images can be viewed here: http://images.nrel.gov/.

Basic Components Of A Solar Water Heating System

A solar water heating system consists of collectors and a heat storage system which may be close to, or remote from, the collectors. Solar radiation strikes the collector and most of it is changed to heat. Some of this heat is lost to the environment; the rest is transferred to the storage tank by the circulation system.

A control and protection system does the following:

• prevents circulation when there is insufficient radiation;
• prevents heat loss from the collectors at night;
• protects the system from overheating, freezing and excessive pressure and;
• protects the users of the system from scalding.

In general we refer to the following as components or sub-systems of any solar water heating system:

Collector

Storage

Circulation

Control and protection

Auxiliary heating