Is gas boosting better than electric boosting of solar hot water in Canberra and Queanbeyan?
What are the installation requirements?
As a supplier and installer of all types of hot water systems I am asked the above question almost every time I provide solar hot water quotes. The following answers will help you to decide which type of boosting is best for you.
Positioning of the storage tank and booster
Both gas and electric boosted solar hot water systems are designed for outdoor use. The tanks are well insulated and will hold water at temperatures hot enough for a shower for up to five days in the Canberra and Queanbeyan region.
Electric tanks can also be installed inside liveable spaces, under houses and in roof spaces as there are no products of combustion/exhaust fumes that need to be vented to the outside atmosphere.
Gas boosted systems can only be installed in these spaces if you have a specially designed gas continuous flow booster attached. This booster will have a flue pipe that must be vented and the vent must terminate to the outside of a building in a well ventilated area.
The booster for most continuous flow systems are usually attached to the front of the storage tank. This requires special consideration as to the direction that the exhaust from the gas booster will face. The rules for the location and direction of flue terminals are complex and depend on the hourly gas consumption of the booster and its type. Generally most gas boosters
- Must be a minimum 300mm away from an opening into a building
- If they are pointing towards a building or structure, they must be no closer than 500mm.
- Must be more than 1500mm below an opening into a building
- Must be no closer than 500mm to an external and internal corner of a building
- Must be a minimum 1000m from a gas meter
- Must be a minimum 500mm from an electricity meter.
All gas, electric and solar storage hot water tanks must be a minimum 50mm above the surrounding ground on a firm, dry and level base.
Both systems will have the same hot and cold water connection requirements. You will use less energy and waste less water if you install the storage tank as close as possible to the hot tap that is most frequently used- the kitchen tap. However, this is not always possible. The next best option is closest to the bathroom most frequently used. Do not install the storage tank on the opposite side of the house to all of the wet areas. This will waste energy and water and will waste your money.
All water supplied to ablution areas must be supplied at a maximum 50°C. Since the water produced in your solar hot water system can be extremely hot it is best to have the hot water to all of your fixtures tempered to 50 °C
If you have a commercial hot water system installation you are likely to use the water at its maximum available temperature of around 85°C. Your Apricus evacuated tube solar hot water system can be adjusted to provide this hotter water.
Electricity and gas supply
Electric boosted solar hot water systems require a dedicated 16amp circuit for the booster. The booster is the only electrical component that can be wired to this circuit.
Both gas boosted and electric boosted solar hot water systems will need a 10amp power socket for the pump and control station. If the system is installed outside, the power point must be weather proof.
The gas line for the gas booster will need to be a minimum 20mm pipe. When the booster is on, it will draw up to 5 cubic meters of gas per hour. You may have to upgrade your existing gas pipe and gas meter to cope with the addition of the gas boosted solar hot water system.