Save before you Generate.

Sure Load-Shedding is a pain and it's not going to go away or get any better in the foreseeable future.

Before investing in an electricity PV generating Solar Power system. 

Reduce your demand. 

A typical water heater draws between 10 -13 kWh's of electricity a day You can save all of this with a correctly sized Solar Water Heater. at a cost of only R26,000

This could be as much as half your total electricity consumption.

The same applies to reducing all you heavy lighting and other appliances where possible. 
Change the Electric out Gas and up grade to an efficient new Fridge / Freezer  rather than continue with the 20 year old one you have at the moment.

The less power you have to generate the less it will cost you to install.

I have customers fully off Eskom power under normal sunny day circumstances all year round  but we could not have done that without first reducing the basic electricity load.

 

Skypower brings you a full range of Solar Power and Load-Shedding solutions.

Each system is tailored to meet the exact needs of your home, office, or business.

All installations are guaranteed with our money-back promise, if it doesn't deliver as we designed it to meet your needs we will take it out and give you your money back.

We are Bryanston based and the majority of our installations are in the area. This means that in the unlikely event that you experience a problem, we can get you back up and running in the shortest possible time. 

We have standardized on a limited range of products from tier-one supplies and always carry stock to cater to any potential system failure.

Our history of post-sales support is why our customers come back to us again should they move house and refer their family and friends to us confident that we won't let them down.

Call  or Whats app us today on 084 876 2891  

Re-installation of

Sky Power Solar Water Heating Systems 

by Insurance Contracted Plumbers

For many years we have taken pride in the quality, the reliability and high performance of our solar installation. We have earned the respect of our customers and won their confidence that we will always do an outstanding job at maintaining the efficiency and cost effectiveness of their systems.

In recent weeks we have become aware, after the fact, that some of our installations have had geysers changed by the customer's "Insurance Company Contracted Plumbers".

Unfortunately many insurance companies insist that they use their sub-contracted plumbers to carry out geyser changes in the event that the geyser has burst. The images below are examples of some of the work such sub-contractors have carried out.

Subsequent to the geyser being changed, some customers have contacted us to "Check Out"their systems as they "seem to have not been performing as well as they had previously".

This is what a Typical Sky Power installation looks like...

It is neat and tidy. It provides for draw and return of water to and from the solar collector. It provides the necessary secondary temperature measuring port and continues to utilize the manufacture's safety thermostat. On the hot side :- temperature is measured via an additional thermostat pocket which reaches into the geyser. It is safe, there is no danger of fire or risk to servicing personnel.

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This is typical of what the some of our customers have after insurance approved plumbers had replaced their geyser having removed and discarded the solar conversion flange in favor of their own technique.

• Thermostat Missing - therefore no safety cut out - allows element to boil the geyser.
• Bare wires pushed into the element have caused them to burn and melt the Element insulator.

Notice the black smoke mark on the flange. 

• Pump has moved to cold water inlet, far from the T2 temperature sensor – 

This will make the system ineffective as it will cause the pump to circulate without reference to accurate temperature readings.

The next two images show the hot side connections of the geyser.

• Above Left
• Solar Return has been moved to the back of T/P Valve.

Returning water via a T connector behind the TP valve renders the TP valve ineffective at the purpose for which it is intended, (potentially making the installation unsafe) and will in many cases open repeatedly when the geyser is up to temperature and the collector is stagnant.

• T3 Solar Temp Sensor clamped to hot water pipe without any insulation. 

This will falsely under-read and cause excessive use of heating element :– 

• Lack of the Thermostat will cause the geyser to boil.  

This will prevent any solar benefit and will cause frequent discharge from TP valve. 

• Above Right.
• Another example at a different site where the T3 sensor has been clamped to the hot water pipe almost half a meter away from the geyser outlet and again without any insulation.

This next picture shows the T2 temperature probe, of another installation, left lying in the drip tray.  

This is the primary temperature measurement in such systems. Without this temperature reference no solar heating benefit will be derived.  In fact it will cause additional losses causing the element to be on for most of the time.

The retro fitting of solar panels to geysers is of course perfectly acceptable and commonplace but does require that accurate temperature measurement is provided and that circulation to and from the solar collector is handled correctly.

This was possible on many of the older geysers that used the Satchwell type of "screw in" element with a built in thermostat pocket and where there was also a separate thermostat pocket in the geyser.

Even the clamping of temperature probes to external pipework can be sufficient in certain circumstances, provided it it close to the output of the geyser and well insulated.

The problems occur when poorly trained staff expecting just to swap an electric geyser out are faced with a solar conversion.

In summary.

Certain sub-contractors are transforming safe and highly efficient solar water heating systems to an ineffective collection of components that provides no benefit to it owner.

It has created the"appearance of a working system" but in reality "all heating is now being derived from electrical energy". 

Disclaimer: I have no idea which insurance companies or contractors have been involved in the provision of these services and am not pointing any fingers.

I do however encourage my customers to call us before contacting their insurance companies, We will happily assist in ensuring that your system is re-built as it should be and will continue to function as it was intended saving at least 85% on water heating costs.

Electricity Back-up systems for Load-Shedding.

As a result of requests from customers who have been very happy with our solar water heating systems, our service and support. We are pleased to announce that we are now offering Solar PV and Electrical Power Back-Up systems in addition to our best of breed solar water heating products.

It is apparent that many suppliers are now entering the Solar Power market. Offering systems ranging from ludicrously cheap to outrageously expensive. 

How do you gauge what you need in order that you can be confident you are not either over or undersold.

In the same way as we did with our solar thermal offerings, we have tried to make the technology and terminology understandable enabling you to be confident that the product you invest in will meet you expectations.

With this easy to operate Excel based calculator. Electricity Backup Calculator You can select how many and what type of lighting and or appliances you want to be able to run during load shedding outages.

Electricity Backup Calculator

The calculator will then indicate how long you will be able to run these lights and devices and the number of batteries that will be required.  It further indicates what size of Inverter you require.

Almost any size of back-up capacity can be provided, it all comes down to money.

The above calculator only considers applications up to 3000W. Beyond this size many other options become available and would need to be designed specifically to you requirements.

What do we need to keep running?

The first objective for most people is light. With light you you can feel safe and secure. 

Secondly for many, entertainment would be the second consideration. You will need enough power to run the DSTV decoder or DVD player and a TV.

Thirdly, few of us can do without our computers for long, the need to have access to email is critical. at home this will also mean needing power for the ADSL router and wireless access point. How many of us have children that need access to the internet for their studies. 

Cell phone smart phone and tablet charges are also on the essential list.

Next many people need to provide power for automation. Garage doors and Gates. Some have built in backup others do not. Perhaps you would like to extend the operation of these devices by keeping them powered during outages.

Then of course being South Africa, come the Security Systems.... electric fences, perimeter beams, perimeter lighting and of course the alarm system itself. 

Many people have noticed that the battery life on their alarms systems and electric fences has reduced due to the increased number of times the dedicated batteries have to run.

It is our belief that the above represents a typical minimum list of appliances we may want to cater for during load shedding of even outages caused by faults or cable theft. If you think of any others please let us know and we will add them into the selection on the calculator.

We have to expect that Load-Shedding will be with us for at least the next 5 Years.

Meet Today's Needs and Add Solar Panels Later.

It is our goal to be able to provide you with the right level of back-up for you needs as the immediate short term goal.

Secondly we have taken care to select a product range that is robust, flexible and upgradeable to be able to allow the addition of  Solar PV panels for Solar Charging as and when it makes both practical and financial sense.

Please feel free to contact us at any time to discuss your requirements and concerns about providing backup for Load Shedding.

Comparing System Efficiency, Performance and Cost

(Re posted from April 2010)
One of the biggest problems the consumer in South Africa has is knowing which Solar Water Heater to select.

In spite of the fact that there are now a great many systems available on the Eskom subsidy list to choose from, it is difficult to separate the good from the ugly, since even the bad systems are accepted onto the scheme. By bad I mean systems which deliver a very low energy replacement.

The public perception is that if a product is listed on the Eskom subsidy scheme it must be OK, right? And certainly if it has SABS Mark approval it should be fit for purpose. Unfortunately, in my opinion, this is not the case.

See our article published back in March 2010. http://www.busrep.co.za/index.php?fArticleId=5387996

The value of rebate a system was eligible for, started out being directly proportional to the energy it could replace. The revised scheme announced in January this year departed from common sense in favour of something purportedly aimed at enabling a five year ROI (return on investment) on systems of different prices, regardless of their energy displacement capability.

So now the situation exists where a 300L system delivering 9kwh of energy receives almost 30% more subsidy than a 200L systems delivering the same energy, this, in spite of the fact that the 200L system will provide better water temperatures and represent a better ROI.

So how can one evaluate the best buy in solar water heating products?

In South Africa this is very difficult since the SABS and Eskom both consider test results and system ratings confidential and do not require a supplier to disclose this information.

We find this rather odd since other countries have open policies on such information.

New Zealand have the Energy Efficiency and Conservation Authority http://www.energywise.govt.nz/solarcalc

The United States for example has the SRCC
http://www.solar-rating.org/
Which also advocates labelling to indicate the efficiency of various solar products.

Fortunately with the benefit of having access to our own reports and certain others from reputable suppliers, we are able to reverse calculate the Q factor (performance rating) of any product in the Eskom scheme from its subsidy value.

With knowledge of the products Q factor and tank capacity it is possible to level the playing fields and gain the ability to compare apples with apples. To this end Sky Power have developed a calculator which we call the “Product Performance Evaluator”.

The calculator simplifies this calculation and produces comparative data specific to the products whose details you have entered which you can then use to make your decision.

Open the Product Performance Evaluator here.

In a separate window browse the Eskom suppliers list and select the products you are interested in from this site. Eskom Suppliers list

On the product Performance Evaluator enter the:

Total installed price of the product
Subsidy value in Rands
Capacity of the system in litres.
The calculator will return:

The Q factor of the product
The Rand value per kWh used to calculate the rebate
The energy required to produce a 40 degree temp rise
The percentage of required energy the product will supply from Solar Input at the SABS test datum.
Cost effectiveness of the product in Rand’s per kWh.
A rating of the products performance.
Having completed this exercise you may be interested to take the next step and get an estimate of product performance throughout the year.

You may then also plug the Q factor, geyser volume and product price information into our Expected Temperature graph tool and you will be able to see the expected temperature delivery of the product month by month according to your location, roof slope and other variable information.

The same tool also allows you to estimate a ROI based on the current and escalated price of electricity, replaced energy and your initial investment.

If you have any difficulty in using the tool please drop us a line and we’ll do our best to help you.

Anomalies of efficiency

Certain SWH systems apparently demonstrate over 100% efficiency!

This of course is clearly not possible and can only come about as a result of an error in measurement or calculation however, there are certain products on the Eskom subsidy scheme which are listed with subsidy values and therefore Q factor measurements, which appear to have been mis-calculated.

It should be noted that this is not a Eskom fault but does possibly indicate an oversight with the issuing of test reports.

In any solar water heating system (as with all other systems) there are theoretical maximums.

SABS test procedures typically issue Q factor measurements relative to 16MJ/sqm/day of solar input.

The maximum Q factor for any product with a collector size of 1 m2 is therefore 16MJ and this would imply 100% efficiency. Energy received being equal to energy delivered.

In the real world, of course, this is not possible since there will always be losses in any energy conversion.

As a case in point one product is calculated to have a 154% efficiency. With a 1.1 sqm collector area and its calculated Q factor of 27.221MJ.

The theoretical maximum of such a product is 16MJ x 1.1sqm = 17.60MJ

It is essential then that, before purchasing a system, you check the measured Q factor for reasonability.

Using the Sky Power product performance calculator available here. http://www.skypower.co.za/content/calculators/Product%20Performance%20Evaluator%201.1.xls

Enter the subsidy value as published by Eskom. The calculator will return the Q factor of the product in kWh. Multiply the kWh figure by 3.6 to convert to it MJ.

Ask the supplier to tell you the absorber area of their product. Divide the Q factor by the absorber area to get energy delivery /sqm

Then divide energy delvery /sqm by the 16MJ X100 (the figure used as the test datum).
The result will be the efficiency of the product as a percentage.

Using Sky Power product as an example:
Q Factor 33.227 MJ and Absorber area 2.4 sqm.

(Q Factor / Absorber area ) = energy/sqm
(energy/sqm /16) x 100 = % collector effeciency

33.227/2.4 = 13.84
13.84 /16= 0.865
0.865 x 100 = 86.5%

Anything over 90%, should be questioned as being unlikely and anything over 100% as impossible.

If in doubt, please call us at Sky Power and one of our technical staff will help you.

Don’t pay for capacity you can’t use.

Why do some solar geyser suppliers recommend bigger tanks than normal geysers?

These are invariably systems based on thermosyphon, the type of systems where you have a tank up on the roof.

This is because of the way thermosyphon works.

The fact that hot water rises and that the thermosyphon process is very slow, the hot water in such systems rises to the top of the tank leaving markedly colder water at the bottom. This design is unable to heat the lower volume of water in the tank.



Click on image to open PDF version.


In large bodies of water such as lakes for example a similar effect is noticed. Divers will witness what is known as the thermocline, a point where the water temperature suddenly drops. The same thing happens in smaller volumes of water where there is no stirring of the upper and lower layers.

What this means is that if you buy a thermosyphon system you can’t really use the full capacity of the tank. So you need a bigger tank than you would have done.

One supplier states that their 300L product has a solar delivery of 240L and their 180 L product can only deliver 160L from solar. This suggests that approximately 20% of the capacity is not usable.

This phenomenon however only applies to thermosyphon systems.

The more modern designs which are actively circulated by the use of small pumps, does not suffer from this loss of capacity. As such it is perfectly acceptable to use your existing geyser or one of the more common geyser sizes that will suit your water demand needs.