A solar driven pump circulates the water from the geyser through the evacuated tube collector outside on the roof, and back into the geyser. With each circulation cycle, the water temperature inside the geyser increases. A Geyser Wise controller regulates the electricity supply to the geyser element. The geyser thermostat monitors whether the backup power to the element is required.
This system is often chosen for the aesthetic value of the installation. Only the collector is mounted outside on the roof. There is no tank outside. The geyser is installed inside the roof.
A further advantage is that the existing electrical geyser can, under certain circumstances be used. The installation method of choice on existing electrical geysers is a Retrofit Kit that is compatible with Kwikot geysers. It includes a new electrical element and thermostat. It is a unique patented Retrofit Kit with supporting SABS performance test certificates.
*Indirect Split Pumped systems available on request (glycol in expansion tank).
Definition of Thermosiphon
These systems work on the principle that when water is heated it gets less dense and rises to the top of the container. Colder, denser, water then moves in to the bottom of the container to replace the hot water. This process will continue as long as there is a sufficient temperature rise of the water to maintain this artificial pressure difference. There is no circulation pump involved.
There are two types of thermosiphon systems, depending how the tank is configured in relation to the collector.
It can be as:
• A close coupled system (Photo above)
• Split system. The tank is not in close proximity to the collector.
These systems are very efficient and normally cheaper that other systems
Ideal for:
• Houses
• Guest Houses
• Hotels
• Clinics
• School / University Hostels
Thermal Systems - Technical information
Evacuated Tube Collector
Evacuated tube heat pipe collector consists of either sixteen or twenty double layered tubes absorbing the sun’s energy. There is no water in the tubes. The heat is transferred via the heat pipe to the manifold section of the collector.
The heat pipe is not directly in contact with the water. Tubes can individually be replaced without compromising the entire collector.
Evacuated Tube (EVT)
Each solar 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 outer tube glass thickness is a minimum of 2mm. This is why the collector conforms to the SABS mechanical test specifications. 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 gases forms a vacuum, which is an important factor in the performance of the solar tubes.
TASOL use three models, namely TAS58/12, TAS58/16 and TAS58/20 (the last number indicating the number of tubes). The nominal dimensions of each tube are 58 mm x 1.8 m. The inner copper part is the heat pipe. The heat pipe uses a volatile fluid in the core of the pipe that evaporates rises and transfers the heat to the common manifold. The cooled fluid then condenses and returns to the bottom of the pipe and the cycle is restarted.
The circulation pump is specially designed to operate from the 12Volt 10 Watt solar PV panel. It is extremely reliable, as it has no brushes or bearing to wear. This will circulate the water from the geyser through to the collector manifold. The pump with the PV panel is sun regulated, and will pump harder with full sunshine, slower when cloudy and will stop at night. A Delta T controller regulates the pump cycles.
The unit is very small, slightly larger than a match box, and is available in 12 V DC, powered by a 10W PV panel, or AC 220 V.
The unit switches on the pump when the temperature of the collector is 7° C higher than that of the tank and switches the pump off when this temperature difference is C.
The unit also presents three useful features:
It will not allow the pump to switch on for the first time in the morning unless the temperature in the collector has reached C, after which it will operate normally. The reason for this is to prevent cold water from being taken to the tank even though the temperature difference is C.
It also has an anti frost cycle which will switch on the pump if the collector temperature is below C and will switch off the pump when the collector temperature reaches C.
It switches off the pump when the tank temperature reaches C, as to protect the tank from overheating.
PV Panel (Solar Panel)
The solar PV panel generates 12Volts DC to power the circulation pump during sunshine hours and must also be mounted on the roof next to the collector.
Battery
This 12Volt battery is used as a back-up source that stores energy for the circulation pump and controller to operate in circulating the water from the tank to the collector manifold.
Retrofit Flange
The Retrofit Kit is an endorsed Kwikot product that will not affect or invalidate the balance of the factory warranty on the domestic electric water heater. This Retrofit Kit makes our proposal on existing pre-installed Kwikot geysers unique. The system is SABS approved.
The retrofit makes provision for two additional water ports on the tank. This enables us to form a dedicated solar loop, which is independent from the demand side loop. No other retrofit method can offer this on pre-installed geysers.
The kit includes:
A new tank flange with seal
New 2Kw electrical element
New thermostat
Additional water ports for the solar loop to and from the collector
The Geyser Wise Max controller replaces the element of thee solar water heating system. Geyserwise Max Smart controller is a ‘Geyser Management Device’ with a number of features and benefits used to manage electrical geysers and solar hot water systems. This intelligent controller is designed to save both energy and money. The controller uses professional techniques and is managed by a micro prosessor.
Characteristics
A clear display of water temperature, time, day, heating mode and malfunction conditions is include:
Auto or manual heating • Easy temperature setting to your requirements (30°C - 65 °C). The factory default is 55 °C
Four different temperature settings.
Daily programmable timer, four time settings
Default setting to coincide with South African municipal load control programs
Battery backup
Multiple protection functions, detecting dry heat, heat failure, earth leakage, probe failure, water leakage, and imminent failure of the heating element.
Features
Multiple Timer Options
Anode Depletion Indicator
Hot Water Leak Detection
Scale Build up Detection
Dry Heat Detection
Element Failure Detection
Electronic Thermostat
AC/DC Control
Delta T Control (split pumped system)
Overheating Protection
When using the controller with a solar water heating system, it can detect freezing conditions. When the temperature reaches 5°C, warm water will be pumped automatically from the tank to the collector manifold.
For a Solar water heating system, it is recommended that a Photovoltaic panel (PV), a 12V DC pump and a battery be used in conjunction with the Geyserwise unit for optimal performance in the event of a power failure.
The product has received the ultimate, the SABS mark of approval. It is also recommended by the ESKOM Demand Side Management (DSM) program, as well as the Central Energy Fund (CEF).
The product has been tested by SABS and conforms to:
Test report
EN60335-2-21
Test report
IEC60335-2-21
Test report
IEC60730-2-9
Test report #
EO909025E
Certificate of Conformity: E0909025S
SABS
PER/RB0036
SABS Certificate #
45150/001
NTCS
57007/001
The independent study conducted by SESSA indicates the electricity saving advantages of the electrical timer installation.
ENERGY PROVIDED BY SOLAR
Before timer use
After timer activation
All Regions - 21,904kWh
Units in Analysis - 36
Cape Town - 7,973 kWh
Units in Analysis - 11
Johannesburg - 11,570 kWh
Units in Analysis - 19
Pretoria - 2,361 kWh
Units in Analysis - 6
All Tasol Solar Water Heating Systems are SABS tested and approved.
*Components are tested as part of a system and not individually. Therefore the system is SABS tested and/ or approved for the mark certificate. The claim cannot be made for the individual components.
*Franchises: For SABS test reports or installation manuals in pdf format, go to Franchise Login area.
