Solar energy is the cleanest and most inexhaustible of all known energy sources. Solar radiation is the heat, light and other radiation that is emitted from the sun. Solar radiation contains huge amounts of energy and is responsible for almost all the natural processes on earth. The suns energy, although plentiful, has been hard to directly harness until recently.

Solar Energy can be classified into two categories, Thermal and Light. Photo-voltaic cells (PV) use semiconductor-based technology to convert light energy directly into an electric current that can either be used immediately, or stored in a battery, for later use. PV panels are now becoming widely used as they are very versatile, and can be easily mounted on buildings and other structures. They can provide a clean, renewable energy source which can supplement and thus minimize the use of mains electricity supply. In regions without main electricity supply such as remote communities, emergency phones etc, PV energy can provide a reliable supply of electricity. The disadvantage of PV panels is their high cost and relatively low energy conversion rate (only 13-15%). Thermal solar on the other hand has average efficiency levels 4-5 times that of PV, and is therefore much cheaper per unit of energy produced.

Thermal energy can be used to passively heat buildings through the use of certain building materials and architectural design, or used directly to heat water for household use. In many regions, solar water heaters are now a viable supplement or alternative to electric or gas hot water production.

Thermal energy obtained from the sun can be used for a number of applications including producing hot water, space heating and even cooling via use of absorption chilling technology.

Using solar and other forms of renewable energy reduces reliance on fossil fuels for energy production, thus directly reducing CO2 emissions. CO2 emissions contribute to global warming, an environmental issue which is now of great concern. The average household can reduce CO2 emissions by as much as 20% by installing an Apricus solar collector.

Flat plate thermal solar collectors have been in use for several decades, but only in relatively small numbers, particularly in Western countries. Evacuated tubes have also been in use for more than 20 years, but have been much more expensive than flat plate, and therefore only chosen for high temperature applications or by those with money.

In recent years the production volume of evacuated tubes has exploded, resulting in greatly lower manufacturing and material costs. The result is that evacuated tubes are now similar in price to flat plate, but with the insulating benefits of the evacuated tube, they are set to become the default choice for thermal solar applications worldwide. Return to questions

Evacuated tubes are the absorber of the solar water heater. They absorb solar energy converting it into heat for use in water heating. Evacuated tubes have already been used for years in Germany, Canada, China and the UK. There are several types of evacuated tubes in use in the solar industry. Apricus collectors use the most common "twin-glass tube". This type of tube is chosen for its reliability, performance and low manufacturing cost.
Each evacuated tube consists of two glass tubes made from extremely strong borosilicate glass. The outer tube is transparent allowing light rays to pass through with minimal reflection. The inner tube is coated with a special selective coating (Al-N/Al) which features excellent solar radiation absorption and minimal reflection properties. The top of the two tubes are fused together and the air contained in the space between the two layers of glass is pumped out while exposing the tube to high temperatures. This "evacuation" of the gasses forms a vacuum, which is an important factor in the performance of the evacuated tubes.
Plese
Why a vacuum? As you would know if you have used a glass lined thermos flask, a vacuum is an excellent insulator. This is important because once the evacuated tube absorbs the radiation from the sun and converts it to heat, we don't won't to lose it!! The vacuum helps to achieve this. The insulation properties are so good that while the inside of the tube may be 150oC / 304oF , the outer tube is cold to touch. This means that evacuated tube water heaters can perform well even in cold weather when flat plate collectors perform poorly due to heat loss (during high Delta-T conditions).

In order to maintain the vacuum between the two glass layers, a barium getter is used (the same as in television tubes). During manufacture of the evacuated tube this getter is exposed to high temperatures which causes the bottom of the evacuated tube to be coated with a pure layer of barium. This barium layer actively absorbs any CO, CO2, N2, O2, H2O and H2 out-gassed from the evacuated tube during storage and operation, thus helping to maintaining the vacuum. The barium layer also provides a clear visual indicator of the vacuum status. The silver coloured barium layer will turn white if the vacuum is ever lost. This makes it easy to determine whether or not a tube is in good condition. See picture below.
Evacuated tubes are aligned in parallel, the angle of mounting depends upon the latitude of your location. In a North South orientation the tubes can passively track heat from the sun all day. In an East West orientation they can track the sun all year round.





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A properly installed Apricus system will last for years to come and require very little maintenance. This is because we have spent a long time designing and reevaluating our main components so that they work well without any involvement of the homeowner. You will notice only high quality components are used that have passed rigorous testing at the factory. The result is a better overall solar system that has less chance of problems over the life of the system. With this said there are a few things that you should be aware of with an Apricus system.

The first thing that you can look for is any evidence of leaks. This can be done by looking for spills, droplets, or even a drop in pressure on the pressure gauge of the APS. Leaks are very rare after the first few days and might be a result of physical damage to the pipes or collector from falling trees or debris. The system can also loose pressure if the PTRV or Pressure/Temperature Relief Valve has opened due to abnormally high pressure or temperatures in the system. The pressure gauge is a good indication if a significant volume of liquid has been lost. Often the installer will record or mark with a red indicator the PSI value that the system was charged to. Please remember that on cold days the PSI gauge will drop and vice versa when the solar loop gets hot. Keeping track of the PSI level every month or so is not required but generally a good idea as it can be the first sign of a possible problem down the road.

If your Apricus system is outfitted with an APS Pump Station then you have a great "window" into your solar hot water system. The flow meter has a glass window which shows you both the colour of the glycol and the flow rate at which it is circulation. First lets discuss the colour. Glycol can easily turn dark due to a number of causes, not all necessarily bad. If the glycol turns a dark colour it is a good idea to test it for pH levels and it's freezing point using a pH tester and good quality refractometer. Your Apricus dealer will have access to these tools.

One recommended form of maintenance is to monitor the output of the system in kWh. This can be done with the press of a button on the Sentinel S3,5 or 6.

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We do not recommend homeowners installing a solar hot water system their self for several reasons.

• Fall protection - In most instances solar collectors are located on roofs which are dangerous to work on and require special training and equipment. Certified Canadian Solar Installers have to undergo Fall Protection training courses to reduce the risk of accidents while working on any elevated structures. Installing and Apricus system on a roof involves carrying not just your own body but also tools, manifolds, tubes, frames, etc to the roof. Leave this to trained installers.
• Risk of burns or scalding - The Apricus collector can reach extremely high temperatures that will instantly turn water into steam when left unconnected or stagnating. This can seriously injure a person who is not trained or expecting those types of temperatures. Also most systems require soldering which involves torches - these can easily burn the operator if not training on how to use the equipment properly. Leave this to trained installers.
• Code requirements - Certain municipalities require additional safety equipment for use with solar hot water systems. A trained installer is able to reference and understand these additional requirements, without creating an unsafe or unapproved environment.
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