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Solar FAQs

How does a solar thermal system work?

Could I use a solar system on my house?

When is it best to install a solar system?

How much thermal solar energy can I expect?

Can I cover my hot water needs with solar?

How can a solar system assist my heating and reduce my energy bills?

What is the life expectancy of a solar system?

How much would be the cost of a solar thermal system?

What is the time required for installing a solar system?

How much maintenance and service costs can I expect?

How do Oventrop collectors compare to and so called “double glass wall” products?

Will the glass break in a hailstorm?

How can you tell if you have lost the vacuum?

How many tubes do you need and how much space is required?

Can I heat my house with these?

Is there a potential of overheating?

How heavy is the collector?

What is the payback or ROI?

How are they shipped?

What is the life of a tube?

Are these new?

Why does one tube have a straight absorber and the other a bent one?

Which side of the absorber in the tubes should face to the sun?

How does a solar thermal system work? - Return to Top

A solar system consists of a solar collector, a multistage pump station and a very good insulated hot water tank. The collector on the roof collects the energy from the sun with its absorbers and transfers it via a solar medium (glycol MH – the non-poisonous type). The heat is transferred through copper pipes into the solar storage tank. The solar station with its built-in regulator transports the heat via a heat exchanger, into a solar storage tank. In this way, the tank enables you to have hot water, even at night or during the days when the sun is not shining.


Could I use a solar system on my house? - Return to Top

The intensity of radiation is enough to make solar a viable energy source. As long as there is southeast, southwest or better still, a southern roof exposure without shade and a 20 – 60 degree angle on your roof to mount collectors on, it will be of great benefit.

When is it best to install a solar system? - Return to Top

It would make most sense to install solar systems during construction of a new home. The advantage of this approach is primarily ease of installation and speed but it also presents a cost saving of about 20% when compared to retrofitting. In any case, it would be wise to install piping for solar heating even if the system will not be installed until years later. Thus when installing later on, the cost will be lower. Also, existing heating systems can be updated and solar systems can be added later. It should be noted, however, that insulation must be considered when installing a new furnace as well as planning to combine a solar system.

In terms of financing an alternative energy system, it may be possible to obtain subsidies from the Federal Government or state to assist in the purchasing of such a system.

How much thermal solar energy can I expect? - Return to Top

A well-planned and well-designed solar system can give a maximum of 70% saving on water heating during a year. From about May to the end of October, it is possible for a solar system to cover 100% of all hot water needs. For the remainder of the year, a reduced output is expected. The cold water supply, however, will be preheated and the rest of the hot water will come from the existing method of water heating that we can supply, without any loss of comfort. In any case, the saving will be substantial.


Can I cover my hot water needs with solar? - Return to Top

The sun produces about 50% of energy use for warm water of 4000 washings or about 3000 dishwasher uses. The other 50% can be supported with electricity or natural gas.

How can a solar system assist my heating and reduce my energy bills? - Return to Top

More and more people want to know how they can save money and cut down on their heating and water heating costs. We can design a combination solar system that will provide your domestic hot water and possibly heat your swimming pool and home. In the winter, the system will simply assist the furnace in heating the home. It must be noted that such systems require a larger number of collectors and storage capacity for the hot water to draw from. Therefore, a modern heating system, in conjunction with solar as well as good insulation, will provide quite considerable savings.


What is the life expectancy of a solar system? - Return to Top

The life expectancy of a solar system is between 20 and 30 years. The system can still produce heat even after 30 years if it receives regular maintenance check ups once a year. Service contracts can be made and are available. Some components are guaranteed for 10 years. Please see contract details.

How much would be the cost of a solar thermal system? - Return to Top

The cost of a solar thermal system for a 4-person household is between $10,000 and $12,000. If the homeowner requires a home heating system package, the cost increases to between $20,000 and $35,000. It is expected that even with additional costs for this option, the payback calculation would be approximately 7-10 years. It should be kept in mind that the system will last between 25 and 30 years. Of course, energy costs with all forms of energy are rising dramatically and will continue to do so in the future.?

?The cost of solar thermal energy is not likely to drop as might be expected by some people, because material and service costs are expected to rise. Thus deferring the purchase of a solar system has no cost benefit. When it comes to funding, financial institutions, credit unions and governments can help. As well, funding is available through us. We will be happy to provide you with assistance and exact information pertaining to all your energy needs.


What is the time required for installing a solar system? - Return to Top

The installation of a solar system will take, on average, about 2 to 3 days. It must be noted that the installation should conform with optical and architectural points of view as well as local by-laws, if they are applicable. Commercial systems are more complex and therefore would require more planning and time to install.


How much maintenance and service costs can I expect? - Return to Top

Like all types of heating, air-conditioning or ventilation equipment, solar systems should receive an annual service check so that they can function at their optimum level. It may be practical to service them at the same time as the air-conditioning system or furnace.


How do Oventrop collectors compare to and so called “double glass wall” products? - Return to Top

In Oventrop evacuated tubes the absorber surface and heat pipe reside in the vacuum environment, which prevents any deterioration in long-term performance. This is not the case with the double glass wall tubes in which both absorber and heat pipe are open to ambient air. Being exposed to air, the copper to aluminum interface between absorber plate and heat pipe is subject to oxidation which may lead to degraded performance over time. Double glass wall tubes are also subject to collection of water from condensation which could freeze and break glass tubes in frost prone environments. These concerns are not applicable to the Oventrop design.


Will the glass break in a hailstorm? - Return to Top

The tubes are manufactured and tested to withstand 35mm (1.38 inch) diameter hailstones. The glass is low-iron tempered glass that is 2.5mm thick.


How can you tell if you have lost the vacuum? - Return to Top

All tubes now being delivered have a silvery coating on the inside at the bottom of the tube. When vacuum is lost, this coating depletes and the tube becomes clear. Older style tubes did not have this feature and you had to rely on observing a build-up of condensation inside the tube as an indicator of vacuum loss.


How many tubes do you need and how much space is required? - Return to Top

For DHW we typically use 4 tubes per person, which assumes 20 gal/person/day usage rate and raising the water temperature from say 55 F to 120 F at a minimum. A 2-person family would need an OV 1/5-8 tube collector and a 50 gal storage tank. A 4-person family needs an OV 1/5-16 tube collector and an 80 gal tank. The 16-tube collector is just over 6ft wide (75.6”) and about 7 ft long (83”).


Can I heat my house with these? - Return to Top

Yes, provided that the home is well insulated, thereby having a low heat loss to the environment. There are no rules of thumb for sizing a space heating array based on square footage of a house. You have to know the heat loss, design temperatures, weather data, and solar radiation available to estimate the size. It will be larger than the DHW component alone.


Is there a potential of overheating? - Return to Top

Yes, any solar thermal collector can overheat if the circulator is off during peak sun hours for a long period of time. The pressure relief valve guards against damage to the system components. The tubes will not “blow-up” or break due to high temperatures.


How heavy is the collector? - Return to Top

Only 110 lbs for the 8-tube, and 220 for the 16-tube when fully assembled.


What is the payback or ROI? - Return to Top

Easily half as long as PV but and on the order of 5-7 years when compared to heating water with electricity. It depends on usage and cost of energy. Ask yourself, “What is the payback on a conventional water heater from the local home center?” Answer, “None” – you just pay and pay and pay from the moment you install it. What is your energy independence worth to you? It should be “priceless”.


How are they shipped? - Return to Top

Collectors are crated and shipped by common carrier. Only single replacement tubes can be shipped via UPS/FEDEX/DHL.


What is the life of a tube? - Return to Top

The statistical “mean life to failure” is 15 years.


Are these new? - Return to Top

No, the technology is about 20 years old. The Oventrop tubes were developed in Germany by Daimler-Benz Aerospace.


Why does one tube have a straight absorber and the other a bent one? - Return to Top

OV 1 tubes have a straight absorber. These tubes can be rotated on axis to compensate or non-south-facing roofs. The OV 5 tubes have a convex absorber providing 20% more surface area. They produce more heat per day than the OV 1’s but cannot be turned on axis and should therefore be used only for true south-facing roofs (+/- 10 deg).


Which side of the absorber in the tubes should face to the sun? - Return to Top

Regardless of which OV tube is used, always face the blue side to the sun. It is treated with a selective coating which absorbs the most energy from the sun’s rays as possible.




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