Solar hot water systems - Solar Geysers
The bulk of the solar hot water industry in Southern Africa did rely on flat panel technology, and solar hot water systems are extremely expensive here. We plan to provide a superior product at a reduced price, on all levels, both domestic and industrial.
All of our solar hot water systems utilize a heat-pipe/Vacuum tube solar panels system to generate heat. We will firstly introduce you to this system and explain how it works before we move into the individual geyser models.
The charm of the Heat Pipe and Vacuum Tube
The Heat Pipe has a very low thermal capacity and very rapid heat conductibility, thus making it a very effective rapid heat-conductive tube. At the same time, it also has the feature of a unilateralist diode for heat conduction. For example, the heat exchange is a direct process: it is transmitted from the endothermic tube to water. By keeping the temperature of the work medium constant (using the special structure of the condenser), the working temperature of the system is well controlled and will ensure the stability of the system in all weather conditions.
The Vacuum Tube has an excellent heat-absorbing feature. The high vacuum in the tube is extremely effective in reducing thermal loses. Its unique carbonic coating is more reliable than the traditional AL-N/AL coating, and its ageing persistence is better.
This selective coating can effectively transfer the direct radiant energy and the diffusion energy from the sun to the heat pipe. This means that the vacuum tube not only absorbs direct sunlight, but also UV rays, greatly increasing its effectiveness, and allowing it to heat water in adverse weather conditions (cloudy / rain).That’s the charm of the vacuum tube and heat pipe.
Advantages of the Super Heat Pipe
- Rapid heat conduction, the speed of the heat conduction is 1000 times that of Copper.
- High heat collecting efficiency, at least 20% more than the average solar system.
- No water runs through the vacuum tubes, thus no incrustation, no corrosion, and the tubes do not burst, even at -40°C and +250°C
- The whole system can work normally when a single pipe is broken, and there will be no water leakage.
- The heat pipes are Hailstone Resistant for hail up to 35mm in diameter.
- The vacuum tube is made of 3.3 high boron silicon glass, giving it extremely high transparency, low inflation and emissivity.
- Solar Heat Pipes meet SABS requirements.
Products
1. Retro fit solar geyser
What is a Retro Fit Solar geyser System?
Basically, we take the solar hot water collectors and attach them directly to your existing electrical geyser (Cobra, Kwikot, Franke etc). This has been a problem in the past, as there are not enough inlets and outlets in a normal geyser to accommodate solar hot water collectors. However, certain valves have recently been developed by a few of the larger Plumbing supplies Manufacturers, which make Retro Fitting possible.
The Retro Fit system is just as effective as our ‘top of the range’ Split/Separated Evacuated Tube System, and is ideal for application in existing houses as well as New builds.. The other major advantage of the Retro Fit system is that it is a lot cheaper than buying a complete solar geyser system. The reasons for this are simple; firstly the solar tanks are very expensive, both in terms of cost and transport. Secondly, the installation costs come down dramatically. Effectively giving you a ‘top of the range’ system at the ‘bottom of the range’ price.
System
The Dako Power solar hot water collector (number 1 in the schematic) converts solar radiation into heat and heats the relative small volume of water in the collectors heat exchange manifold. When the controller (number 2 in the schematic) detects that the water in the collector heat exchange manifold is 8 °C warmer than the water in the geyser the hot water circulation pump (number 3 in the schematic) is activated. The pump will force the warmer water from the collector into the geyser and replace it with cooler water from the geyser. When the heat exchanger manifold of the collector has dropped to below 4 °C above the geyser temperature the circulation pump is stopped. The solar hot water collectors will now heat this water to 8 °C above the geyser temperature and the controller will activate the circulation pump again. This cycle is continued all day long until the geyser has reached its user defined maximum permitted temperature or the sun has gone down.
The solar controller also takes control over the geyser element. If it should happen that there is not enough solar energy available to heat the geyser or all the hot water is used over night, the controller can activate the geysers electric element to boost the temperature. The controller allows the user to specify times and temperatures when the controller would be allowed to activate the geyser element. This function results in further electricity savings since the geyser’s element will never activate unless it is absolutely necessary.
This heating system is made up of either one or two solar hot water collectors (depending on the size of your existing geyser – there is a table below indicating the various solar hot water collector sizes to geyser size), a circulating pump, a computer control system and 2 specialized valves.
| Panel Size | Heating Capacity |
| 18 Heat Pipes | 160 L |
| 36 Heat Pipes | 300 L |
The solar hot water collectors are made up of 18 heat pipes each, connected to a manifold. The absorption coefficient in the vacuum tubes is more than 0.94.
The circulating pump is a German made Wilo pump. It has a very low energy consumption level, low noise level and is extremely reliable and long lasting.
The computer controller is imported from Italy, and is extremely reliable and very user friendly.
Panel Specifications
Total Energy Consumption of 18 Tube Retro-fit Solar Geyser systems for 150litre geyser
The figures are based on a ‘worst case scenario’ situation, where all the hot water is used at the end of the day, and the electrical element is needed to heat the tank from 20ºC to 55ºC in the early hours of the morning (before the sun is up). Our calculations are formulated on the assumption that our 18 tube panel is used in conjunction with a 150Litre geyser with a 3 KW electrical element as back-up. We also referred to energy figures available on the Eskom website.
| Appliance | Wattage | Number of appliances | Running time (hours) per day | Total kWh Per 24hours |
| Wilo Pump | 67W | 1 | 3 | 0.2 kWh |
| Computer /Controller | 3W | 1 | 24 | 0.072 kWh |
| Element (2KW) | 3000W | 1 | 2 | 6 kWh |
| Total | 6.272 kWh |
2. Diamond Series, Separated system (top of the range)
This heating system is made up of:
- One 22 tube solar hot water collector (for a 200litre tank) or two 18 tube solar hot water collectors (for a 300litre tank).
- A Specialized 200 or 300 litre water tank.
- Circulating pump.
- Computer control system.
The American A.O.Smith enamel coating electrical water tank has a 200 or 300litre capacity and is pressurized, with a working pressure of 0.6MPa. The tank is made of food grade stainless steel and an anti-corrosion outer enamel coating, it is insulated with a layer of polyurethane foam and uses special inside buckling technology. It is both firm and beautiful, and can be placed anywhere in or outside a household. There is a built in Electrical element, so water temperature can be topped up using electricity (this is only needed on those rare occasion where there is complete sun black out for a number of days, or when large quantities of hot water are used in the evening and more hot water is required early the next morning).
The circulating pump is a German made Wilo pump. It has a very low energy consumption level, low noise level and is extremely reliable and long lasting.
The computer controller is imported from Italy, and is extremely reliable and very user friendly.
Operation
The operation of the separated series is very simple; here is a brief overview of how it works:
Mains water is pumped directly into the geyser. There are two temperature sensors, one in the tank and one in the solar panel collector. The sensors are connected to the computer controller, when the controller detects a temperature difference of more than 8°C between the tank and panels; it initiates the pump, thus circulating the water (i.e. the hot water from the panels moves into the tank, being replaced by colder water from the tank). This water circulation is a continuous process, until the water in the tank reaches a preset optimal temperature (this temperature can be set by the owner of the system, recommended temp is between 55°C and 65°C). As mentioned earlier there is an electric element in the geyser, and the temperature can be topped up using electricity if needed. This should not often be the case, as our system should cut out up to 95% of electricity used in a household’s water heating needs.
Total Energy Consumption of a 300 litre full Separated Series Solar Geyser systems
Please note that the figures below relate to the total energy consumption necessary to run one 300 litre solar geyser system per day. The figures are based on a ‘worst case scenario’ situation, where all the hot water is used over night, and the electrical element is needed to heat the tank from 20ºC to 55ºC in the early hours of the morning.
| Appliance | Wattage | Number of appliances | Running time (hours) per day | Total kWh Per 24hours |
| Wilo Pump | 67W | 1 | 3 | 0.2 kWh |
| Computer /Controller | 3W | 1 | 24 | 0.072 kWh |
| Element (2KW) | 3000W | 1 | 2 | 6 kWh |
| Total | 6.272 kWh |
3. Platinum Series, Non -Separated system Pressurized (Middle of the range)
Gold series products apply the latest ''KRD- Winding-pipes technology'' and are developed by several international well-known energy research professionals of USA lv Kun Bei Solar Energy. Using Research based on KRD technology, they have improved on the disadvantages of traditional solar water heater such as limited hot water, small water output, slow heating time etc. They have successfully developed the technology of “secondary heat exchange”, which can integrate high temperature, high efficiency with fast circulation of heat water perfectly. Gold series products are in the cutting edge of solar application industry.
Platinum Series solar water heater (G470581800):
Inner tank: Imported SUS3042B Food Grade Stainless Steel;
Tank Size: 250 Litre or 310 litre
Outer shell: Galvanized sheet;
Heat insulation layer: 5060mm imported polyurethane integral foaming;
Bracket: Reinforcing aluminum alloy;
Vacuum tube: Hard borosilicate glass tube 3.3;
Copper Coil: 38 meter;
Working Pressure: 0.6-0.8Mpa;
Fixing of copper coil: 3 long stainless steel bar and PP material
Operation
The pressurized solar water geyser utilizes the high absorption rate and low projection rate coating of the vacuum tube, and it changes solar radiation into heat energy. Meanwhile the copper pipe inside the vacuum tube quickly transfers heat into the tank. This leads to the gradual increase in water temperature of the entire tank until the preset temperature is reached. This system is computer controlled, but does not require a pump.
4. Gold Series, Non -Separated system, Non - Pressurized (Bottom of the range)
The Gold series works in a very similar manner to the Platinum series, the main difference is that the water tank is not pressurized. Being a gravity feed geyser, the higher up off the ground it is, the more water pressure it will produce. It too, is controlled by a computer and does not need a pump. This model is ideal for rural use as well as in low cost housing.
Guarantee
So far as our products are concerned, we are extremely confidant in the quality and effectiveness of our range of Solar geysers. We are given comprehensive long term guarantees by our manufacturers on all components of the system and we pass these guarantees onto you. They are as follows:
| Component | Guarantee |
| Collector | 5 years |
| Heat Pipe | 5 years |
| Tank | 5 years |
| Controller | 2 years |
| Pump | 2 years |
Any components found to be defective within the guarantee period will be replaced without charge (provided the faults/defects are due to manufacturer or installer error).
So far as installation guarantee is concerned, we outsource the installation work to a number of plumbing firms; each has its own guarantee on their installation work. We can provide more information separately regarding this.