The installation of a solar water heater enables you to make a positive contribution to our global environment, while also saving you money in the long run.
This simple act can save 40% - 50% of your electricity usage, which means that our local power utility will burn less coal or gas to generate electricity. Reduced burning of fossil fuels will cut the amount of greenhouse gases released into the atmosphere, especially carbon dioxide (CO2). Solar water heaters are therefore one of the best long-term investments you can make - both financially and for the environment. Moreover, solar energy is not affected by our current shortage of electricity.
Besides making a positive contribution to the environment, you gain:
A hedge against spiralling energy costs.
Free hot water for life.
More independence from erratic power supply.
An investment in your children's future.
The release of much needed energy to industry.
An increase in the resale value of your property.
A good quality, correctly installed system should be able to save at least 40% of an average household’s electricity bill.
Based on current electricity prices paybacks are typically 5 years or less, depending on geographical area, water consumption patterns, number of people in the household, type of system chosen and energy cost.
Solar water heating is a system for heating water using energy from the sun. Solar energy is collected by a solar collector (either a panel or a set of evacuated tubes) which is then connected by means of pipes to a hot water storage device such as a hot water cylinder. A correctly designed solar water heater system is an extremely simple and reliable concept. Today several million homes and businesses all over the world use solar water heating, which supplies 40% – 70% of all the energy your home or business needs for water heating.
You’ll need a storage tank with solar ports, a solar collector (panel or tubes) and a minimum of 4-6 hours of daily direct sunlight. The XSTREAM range of storage tanks is a standard solar unit – the extra fittings required are standard built-in.
You’ll find “split-systems”, “thermosiphon systems” and “pumped systems” and a variety of temperature controllers as additional options.
We believe a thermosiphon system (where the tank is installed at a point above the panel) is the best option as it does not contain any working parts and it works on a basic law of nature: heat rises. The heated water will rise and remain inside the storage tank while the colder water at the bottom of the tank will circulate through the panel to be heated again.
First you need to work out your hot water needs. A unit that is too small will not provide enough hot water, so slightly over-sizing your hot water cylinder is recommended. However, if it is too big it will be uneconomical. An accepted way to size a system is to allocate 50 litres of water per person in your household and then to add an extra 50 litres for appliances that draw a large amount of hot water from the geyser. By over-sizing a system slightly you can maximize the hot water achieved by solar gain.
The ideal temperature of your hot water storage tank is between 55° C and 60° C. Most solar systems heat the water to between 55° C – 65° C, but some can heat much higher than that. You need to be aware of over-performing systems so that you are not scalded by the hot water. Unless otherwise required the water temperature at the point of use should be at least 38° C for domestic fixtures such as baths, basins and showers and at least 45° C (in order to melt fats) for sinks. The temperature is not meant to exceed 55° C at any point of use. Typically a mechanical temperature mixing valve can/must be installed.
The storage tank must be properly insulated to minimize heat loss. It should provide electrical back up (element & thermostat fitted) and must have minimum maintenance. The regular replacements of anodes are not only costly, but if not properly maintained, may also cause the guarantee of the supplier to become null and void. Therefore rather use non-ferrous products with no need for anode replacements.
Installation options are also important. Ideally a tank should be designed to be installed anywhere (e.g. uncovered on the roof of the building – in which case you must insist on IPX4 rating).
Position the installation carefully to minimise water wastage and heat loss to the hot water draw-off point.
The solar collector should be properly insulated and the casing material of high quality non-corrosive material – aluminium is a good option for panels. It should provide fixing points to the roof to enable a secure fit.
The ratio between the absorption area and the volume of water to be heated should be in balance. This is very important. A good ratio is 55-75 litre per m² panel or 10-12 litre per tube.
In the case of a “direct solar system” water is heated inside the solar collector and the heated water is then stored inside the storage tank – this system is also referred to as an “open system”. These systems are suitable in areas where there are no freezing conditions.
The “indirect solar system”, also referred to as the “closed system”, uses an anti-freeze mixture as heating fluid, and a heat exchanger is built into the SHW system. The heated anti-freeze fluid now circulates between the SHW’s heat exchanger and the solar collector, and the water inside the SWH absorbs the heat from the heat exchanger. This system is well suited, and specially designed, for areas where frost occurs used with flat plate collectors.