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| Initial | APPROVED 209.07.11 |
| Appeal | The ancient Egyptians worshipped the sun, because they understood that it was a source of life, light, energy and warmth. With today's technology that warmth can be used to heat water. In the UK we tend to feel that our share of sunshine is rather meagre, but in fact there is a substantial amount of solar heat that can be gathered both in the summer and the winter. |
| Amended | The ancient Egyptians worshipped the sun, because they understood that it was a source of life, light, energy and warmth. With today's technology that warmth can be used to heat water. In the UK we tend to feel that our share of sunshine is rather meagre, but in fact there is a substantial amount of solar heat that can be gathered both in the summer and the winter. |
| Returned | The ancient Egyptians worshipped the sun, because they understood that it was a source of life, light, energy and warmth. With today's technology that warmth can be used to heat water. In the UK we tend to feel that our share of sunshine is rather meagre, but in fact there is a substantial amount of solar heat that can be gathered both in the summer and the winter. |
Solar heat is gathered by solar collectors, which come in a variety of types and size, each with its own merits. The simplest is the flat plate collector, which comprises a black heat absorbing plate made of aluminium, with copper tubes welded to it. Water passes through the copper tubes, so that the heat gathered by the plate is transferred to the water, which is then stored in a collector tank. At the back the plate is heavily insulated, and the front is enclosed by a sheet of toughened glass. The plate should face between south east and south west, but ideally south. It should be angled between 30 and 40 degrees to the horizontal in order to gain the most heat. Most houses have a roof either sloping or flat, which provides a suitable location for a panel.
Cutaway view showing internal copper heat exchanger
A good flat plate collector will gather 400 kWh of heat energy per annum for each square meter (evacuated tube collectors are more efficient, and gather more heat per square metre, but cost more). Each installation needs to be assessed for the most suitable type of collector, which will depend on the roof space available, accessibility, and of course, cost. Using a 2.75 m² panel, 1,150 kWh of energy can be collected, or with 4 m², 1600 kWh. Since the average home uses some 2,500 kWh for hot water, it can be seen that the Solar collector can provide between 45% and 60% of the annual hotwater energy requirement.
A Solar hot water system will last over 20 years, and so when calculating cost savings, remember that the cost of fuel will increase every year, which increases the saving each year. In terms of environmental pollution, it will save between 0.25 and 0.5 tonnes of CO₂ per annum when replacing gas, and well in excess of 0.5 tonnes per year for electrically heated hot water. That is a significant reduction in CO₂ emissions from each house.
Hot water systems need to be designed to protect against the formation of Legionella bacteria. Atmos Solar hot water systems are designed so that the water temperature is always raised to 60°C, at which temperature all Legionella bacteria are killed dead! Thus they are extremely safe in this respect.
Water from the storage tank is circulated around the collector panel, collecting heat from the sun. A 22mm copper heat exchanger coil immersed in the tank transfers the heat to the tap water, so that it can be used for low pressure or mains pressure applications.
The MonoSolar has an in built control system which protects it against temperature extremes. If there is a risk of overheating in the summer, or of freezing in the winter, the circulation of water is automatically stopped, allowing water to flow back from the collector into the empty discharge space in the storage tank.
This means the Atmos MonoSolar can operate without the addition of glycol antifreeze. The storage tank and solar collector form a closed circuit, making the unit maintenance free.
12 JUL 2007
Like all solar heating systems, an electric circulation pump is needed to pump the water round the system. This uses electrical energy, but the MonoSolar control system cleverly uses a multi-speed pump. On start up it runs for two minutes at high speed, and then the speed drops step by step to low speed for the rest of the time. So whilst heat is being collected, the pump uses only 23 watts of electricity. This is a hidden but significant energy and cost saving feature.
A thermostatic mixing valve ensures that the water flowing from the tank can be adjusted to meet user requirements, and avoid any possibility of scalding.
The MonoSolar may be used to pre-heat water to feed the Atmos Multi or the Atmos Compact. It may also be used to feed an existing vented or unvented hot water tank.
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