From a solar collection efficiency point of view there is not a lot of difference between the panels from reputable suppliers. You should be looking at other things such as street appeal, longevity, on-going maintenance costs, equipment price, ease of installation, cost of installation and warranty before you start looking too hard at performance.
Having said that, Thermocell panel uses a unique high efficiency evacuated plate as the working part of the panel. The panel maximises the benefits of both the common types of solar heating panels, ‘evacuated tube’ and ‘traditional flat plate’ models.
Also make sure you are comparing like collector aperture areas with like collector aperture areas. At the end of the day, the amount of effective collection area you have is what really matters. Take a look at the Consumers' Institute article on solar hot water. Check also how the panels perform overnight, not for collection, but for losses.
Last Updated Wednesday, 09 July 2008
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To put it another way is to measure what you would have if you invested $10k into the bank at 8.6%pa and the return on investment if you spent the same $10k on solar on your roof would equate to approx 15-18%pa, or approx 75%pa saving on your electric hot water bill. The industry standard payback is 5-7 years based on prices of 3 years ago. Last Updated Wednesday, 09 July 2008
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This is difficult to answer as each household uses hot water differently and for any given time during the year the sun only generates a certain amount of energy per square metre. So all that can be ever claimed is that on average, over a year you can expect solar to provide up to 75% of your hot water needs
Last Updated Wednesday, 09 July 2008
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Thermocell solar collectors and information
This section deals with:
Thermocell solar collectors and information about the panels themselves.
Yes, our panels with the unique serpentine waterway can withstand mains pressure and then some. Mains pressure systems operate with a 50 metre head and our panels can withstand in excess of 150 metres of head. Last Updated -
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No, the evacuated plate does not come into contact with the circulating water and the glazing arrangement prevents rain ingress. The evacuated plate goes through a phosphate bath process before the application of industrial undercoats and top coats and we use either a non-corrosive steel or colour steel for the cases. For added comfort for our customers as from 2008 our solar panels carry a 12-year warranty period. (Other system components subject to manufacturer’s warranty.) Last Updated -
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Thermocell solar systems are installed complete with a controller and digital display, which shows the temperatures of the panels and the hot water in your cylinder and indicates when the pump is running.
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Yes, Thermocell’s digital control unit and pump protect the panels from freezing. The Thermocell controller incorporates three panel sensors, one of which is a dedicated frost detector. The standard Thermocell system is good for areas that experience light to moderate frosts. The evacuated plate operation of Thermocell panels mean that only a small amount of relieving water needs to be pumped to offset the effects of frost. Where prolonged, heavy frosts are experienced we recommend a glycol circuit, which can safely withstand any amount of frost.
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So long as the power is left on to the solar controller the solar system will continue work and keep the cylinder temperature hot ready for your return.
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Solar panels will generally not produce a high output water temperature in winter. They will still provide a significant contribution to your hot water heating when you consider that the cold water inlet temperature will be less than 10°C. Having said that, we have had a Christchurch customer who found that his hot water cylinder element had been accidentally switched off in October, but hadn't noticed any shortage of hot water until June the next year. Last Updated -
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We design and test each panel so that it will be as good in 20 years time as the day it leaves the factory. And panels that were installed in the early 1980's are still working just fine. For added comfort for our customers as from 2008 our solar panels carry a 12-year warranty period. (Other system components are subject to manufacturer’s warranty.) Last Updated -
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Firstly, a pumped system is more efficient than a thermosyphon system for the same collector area. More importantly for New Zealand conditions, a pumped system allows for true flexibility in building layout, there are no restrictions on the solar panel and hot water cylinder configuration so that the hot water cylinder can be placed for optimum usage and the solar panels for best performance. Thermosyphon hot water cylinders are normally located on the roof and the roof structure may need to be strengthened and may need an Engineer’s report to accommodate it. Last Updated -
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We like to think that the street appeal of our panels is second to none, we don't compromise on performance; it doesn't get simpler to install our panels and there is no maintenance requirement.
A panel containing a lot of water or working fluid will take a lot more energy to warm up than a more agile system, such as ours, which holds about a cup of water per panel. The losses our system incurs from overnight cooling, which detracts from overall performance in cooler areas, is particularly low. Our own microprocessor controller and display forms the heart of our frost protection systems. And we did mention that word "reputable" we have been building and installing our solar panels for over twenty-five years now and we like to think we deserve our solid reputation.
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Questions about hot water cylinders
This section deals with:
Questions about hot water cylinders from Thermocell
You want to make sure that your hot water cylinder is designed for New Zealand conditions. All Thermocell ‘Sunstore’ cylinders are built to meet NZ MEP’s requirements (A-Grade Watermark standard) these hot water cylinders are designed for maximum efficiency in our cooler climate. Our ‘Sunstore’ cylinders are also design to maximize the efficiency of the solar panels. Last Updated -
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For the best efficiency with solar gain, the cylinder needs to be within 20m of the collector location, just remember closer the better for performance.
This helps with seasonal gain in the marginal times only (winter), as the collector will need to move the fluid down to the cylinder as fast as possible, if the runs are long then it never accually makes it to the cylinder before the pump turns off.
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Low, Medium or Mains Pressure is available. All Thermocell ‘Sunstore’ cylinders are built to meet NZ MEP’S requirements (A Grade Watermark standard) Last Updated -
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Cylinder temperature can get up to 85oC, but all cylinders in NZ require a tempering valve so the water temperature to your taps is no more than 55oC. The Thermocell panel is designed to start operating at low temperatures and designed not to boil the cylinder water, eliminating thermal stress on the hot water cylinder, harm to the roof penetrations and the extra valving necessary to dump boiling water on to the roof and down plastic gutting.
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The cylinder should be located in the best position for your home plumbing needs. Our solar system is very adaptable so the plumbing needs are the most important consideration. The cylinder should be positioned inside the home (not recommended outside or on the roof). Last Updated -
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You are less likely to run out of hot water with a Thermocell solar hot water system than you are with a conventional (i.e. non-solar heated) hot water cylinder. The hot water cylinder and controller designs mean that there is always a reservoir of hot water waiting to be drawn off in the hot water cylinder. Should there have been insufficient sunshine to heat the water to a useable temperature, the electrical heating arrangement will automatically "top up" the temperature. Last Updated -
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The installation is covered by Thermocell for the Canterbury area, or we take out the installation cost and the local plumber adds in, approx $1500 for the installation.
This seems to be the average cost with any solar installation to be done correctly.
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All Thermocell systems are installed by a Thermocell approved craftsman or registered plumber and have completed EECA’s Solar installation training course. Last Updated -
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Any liquid/metal/liquid interface introduces thermal resistance. Going to a glycol circuit option will reduce annual performance by about 5%. This is the same with any solar system that has a secondary circuit.
Last Updated Wednesday, 09 July 2008
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While we don't recommend drinking it, glycol is safe for humans. Indeed, some years ago a number of European wine manufacturers used to add it to their wine to provide extra flavour. We use glycol loop systems only for New Zealand's coldest regions. The glycol is contained in a secondary circuit separate from the water circuit. Last Updated -
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AL842 Artline collector (1238)
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