Frequently Asked Questions & Answers
Xstream Solar Hot Water Cylinders (Pty) Ltd. All Rights Reserved.
1.
Q: Why a solar water heating system?
A: Solar water heating systems provide quality hot water at a lower cost than heating with electricity. Hot water is a constant daily expense; other large household appliances, like air conditioners & heaters, are seasonal expenses. If you are an individual using electricity to heat water, you will pay for a solar hot water systems over the next 4 to 8 years whether you get one or not! Invest today - let the sun make your monthly payments. The choice is not about spending money - but what you are getting for your money.
Any time you use solar energy to offset the amount of fossil fuels being burned, you contribute to everyone’s health and welfare. Operating one solar water heater instead of an electric water heater saves the equivalent of nine barrels of oil every year and reduces carbon dioxide emissions.
Q: Why a solar water heating system?
A: Solar water heating systems provide quality hot water at a lower cost than heating with electricity. Hot water is a constant daily expense; other large household appliances, like air conditioners & heaters, are seasonal expenses. If you are an individual using electricity to heat water, you will pay for a solar hot water systems over the next 4 to 8 years whether you get one or not! Invest today - let the sun make your monthly payments. The choice is not about spending money - but what you are getting for your money.
Any time you use solar energy to offset the amount of fossil fuels being burned, you contribute to everyone’s health and welfare. Operating one solar water heater instead of an electric water heater saves the equivalent of nine barrels of oil every year and reduces carbon dioxide emissions.
2.
Q: How does a solar hot water system (SHW) or geyser work? What do I need?
A: You’ll need a (solar) storage tank, a solar absorption panel 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.
Q: How does a solar hot water system (SHW) or geyser work? What do I need?
A: You’ll need a (solar) storage tank, a solar absorption panel 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.
3.
Q: What is the difference between a “direct solar system” and an “indirect solar system”?
A: In the case of a “direct solar system” water is heated inside the solar panel 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 and where treated water is supplied.
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. The heated anti-freeze fluid now circulates between the SHW’s heat exchanger and the panel, 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 or for harsh water conditions.
Q: What is the difference between a “direct solar system” and an “indirect solar system”?
A: In the case of a “direct solar system” water is heated inside the solar panel 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 and where treated water is supplied.
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. The heated anti-freeze fluid now circulates between the SHW’s heat exchanger and the panel, 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 or for harsh water conditions.
4.
Q: What type of anti-freeze is used?
A: Make sure you use a non- toxic type, like the XSTREAM™ panel guard.
Q: What type of anti-freeze is used?
A: Make sure you use a non- toxic type, like the XSTREAM™ panel guard.
5.
Q: What is the best way of installing an SHW system?
A: Remember this important law of nature: “heat rises”. Therefore, the best way of installing an SHW system is to have the SHW above the panel to allow thermosiphoning to take place. No working parts are necessary for this and once the panel is colder than the heated stored water the system shuts off automatically (e.g. at night time).
XSTREAM range of SHW systems are SABS approved for exterior installations and can be manufactured to match your roof colour.
If however, you want to install the SHW at a point lower than the panels, a circulation pump will be required. Various types are available, but avoid using a normal timer type - should the electricity supply be interrupted (chances are very good for this!), the timer will need to be reset, or the system might be circulating at night-time, and the water will be cooled down. Rather opt for a photovoltaic pump or a temperature differential system.
Q: What is the best way of installing an SHW system?
A: Remember this important law of nature: “heat rises”. Therefore, the best way of installing an SHW system is to have the SHW above the panel to allow thermosiphoning to take place. No working parts are necessary for this and once the panel is colder than the heated stored water the system shuts off automatically (e.g. at night time).
XSTREAM range of SHW systems are SABS approved for exterior installations and can be manufactured to match your roof colour.
If however, you want to install the SHW at a point lower than the panels, a circulation pump will be required. Various types are available, but avoid using a normal timer type - should the electricity supply be interrupted (chances are very good for this!), the timer will need to be reset, or the system might be circulating at night-time, and the water will be cooled down. Rather opt for a photovoltaic pump or a temperature differential system.
6.
Q: What is the best location for an SHW installation?
A: A good average angle (roof pitch) is about 35 - 40°C. Plus or minus 20° from true north. Should it not be possible to obtain the “perfect” position, additional panels could be considered to increase the absorption area to compensate for the inefficient position.
Q: What is the best location for an SHW installation?
A: A good average angle (roof pitch) is about 35 - 40°C. Plus or minus 20° from true north. Should it not be possible to obtain the “perfect” position, additional panels could be considered to increase the absorption area to compensate for the inefficient position.
7.
Q: I have freezing conditions during winter. Won’t my panels freeze up and burst?
A: No, not if you make use of the indirect system and your panels are filled with XSTREAM™ panel guard which is a non-toxic anti-freeze.
There are high pressure vacuum tubes available that can be connected directly onto the Xstream Mainstream™ (direct solar) systems that will also allow for freeze protection. Please ensure that you opt for tubes with at least two millimetre wall thickness in order to have some hail protection.
Q: I have freezing conditions during winter. Won’t my panels freeze up and burst?
A: No, not if you make use of the indirect system and your panels are filled with XSTREAM™ panel guard which is a non-toxic anti-freeze.
There are high pressure vacuum tubes available that can be connected directly onto the Xstream Mainstream™ (direct solar) systems that will also allow for freeze protection. Please ensure that you opt for tubes with at least two millimetre wall thickness in order to have some hail protection.
8.
Q: What size storage tank do I require?
A: On average one person will use 50 - 67 litres of hot water per day. Therefore a household of 4 people will
need at least a 200 litre system and a 3 m² solar panel.
Q: What size storage tank do I require?
A: On average one person will use 50 - 67 litres of hot water per day. Therefore a household of 4 people will
need at least a 200 litre system and a 3 m² solar panel.
9.
Q: What type of glazing is used for
the panels? - Is it protected?
A: Ensure your solar absorption panel
is hail resistant.
Q: What type of glazing is used for
the panels? - Is it protected?
A: Ensure your solar absorption panel
is hail resistant.
10.
Q: What size panel goes with what
size SWH?
A: Work on a ratio of 65 - 80 litre geyser capacity per 1m² panel size.
E.g. 200 litre cylinder = 3m² panel at 67 litre / m²
Q: What size panel goes with what
size SWH?
A: Work on a ratio of 65 - 80 litre geyser capacity per 1m² panel size.
E.g. 200 litre cylinder = 3m² panel at 67 litre / m²
11.
Q: Can the Solarstream™ (indirect system) and Mainstream™ (direct system) SHW work off electricity for those rainy days?
A: Yes, it is standard electrical adaptable. Fitted with an element & thermostat. The thermostat (setting of the temperature) is adjustable and it is advisable to set it at 35-45 Cº in summertime and 45-50 Cº in wintertime.
Q: Can the Solarstream™ (indirect system) and Mainstream™ (direct system) SHW work off electricity for those rainy days?
A: Yes, it is standard electrical adaptable. Fitted with an element & thermostat. The thermostat (setting of the temperature) is adjustable and it is advisable to set it at 35-45 Cº in summertime and 45-50 Cº in wintertime.
12.
Q: Will my water be hot enough?
A: Yes! Solar heated water is often hotter than the thermostat setting on your water heater. A back-up electric heating element is fitted in your storage tank & will automatically heat water to the tank’s thermostat setting.
Q: Will my water be hot enough?
A: Yes! Solar heated water is often hotter than the thermostat setting on your water heater. A back-up electric heating element is fitted in your storage tank & will automatically heat water to the tank’s thermostat setting.
13.
Q: What about cloudy weather?
A: A solar system will typically collect about half the solar energy of a clear, sunny day on an overcast day. Clouds block many of the visible wavelengths of sunlight, but much of the solar energy still gets through.
Q: What about cloudy weather?
A: A solar system will typically collect about half the solar energy of a clear, sunny day on an overcast day. Clouds block many of the visible wavelengths of sunlight, but much of the solar energy still gets through.
14.
Q: How much will I save by using an SHW to heat water?
A: A good quality, correctly installed system should be able to save at least 40% of an average household’s electricity bill.
Q: How much will I save by using an SHW to heat water?
A: A good quality, correctly installed system should be able to save at least 40% of an average household’s electricity bill.
15.
Q: How will the solar heated hot water remain inside the storage tank? Will it not reverse-syphon to the solar
panel during night time?
A: The hottest water molecule is also the lightest molecule and will remain at the highest point inside the storage tank - therefore it will not cool off overnight by reverse syphoning -that is if the storage tank is positioned at a point above the solar absorption panel, like in the case of a thermosyphoned system. Should a pumped system (or forced circulation system) be used and the pump should run overnight (e.g. if the timer switch should malfunction) then the system will cool off, as the solar absorption panel now becomes a heat radiation panel.
Q: How will the solar heated hot water remain inside the storage tank? Will it not reverse-syphon to the solar
panel during night time?
A: The hottest water molecule is also the lightest molecule and will remain at the highest point inside the storage tank - therefore it will not cool off overnight by reverse syphoning -that is if the storage tank is positioned at a point above the solar absorption panel, like in the case of a thermosyphoned system. Should a pumped system (or forced circulation system) be used and the pump should run overnight (e.g. if the timer switch should malfunction) then the system will cool off, as the solar absorption panel now becomes a heat radiation panel.
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Last updated 28.11.11
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