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P.I.R.B. Registered Plumbers. Jojo Tank Approved Installers. Solar Certified.
Replace burst geysers
Replace thermostat and replace element
Replace Pressure Relief Valve (PRV)
All makes and sizes
Repair of solar geysers
Solar Geyser Retrofits
Flat Pate collectors
Evacuated Tube Collectors
Repair of heat pumps
Retrofit heat pump to existing geyser
Various sizes and options
Heat Pumps use only 25% energy
Geyserwise geyser controller
Controls circulation pump
Provides useful information
The main decision that needs to be made by the customer when selecting a solar geyser is the size. Solar geyser installations are very common and there is a standard installation.
Need a Plumber for your Geyser or Solar Geyser? Geyser concepts explained by a plumber.
Geyser size guide
Geyser size depends on the amount of persons that are using water from the solar geyser. The most common sizes are 150L and 200L. When using an electric only geyser the geyser is heated as water is used. With a solar geyser hot water needs to be stored for long periods without being heated and should be sized larger than electric only geysers.
300L geysers are very heavy and require bracing and structural modification to roof trusses. Most customers settle for a 200L geyser and enjoy the savings of the 200L geyser and subsidize the shortfall with electricity.
|Persons||Geyser Size||Solar Geyser Size|
|2 Persons||150 L||200L|
|3 Persons||150 L||200L|
|4 Persons||200 L||300L|
|5+ Persons||200 L||300L + 50L per person|
Solar Collector size guide
Collector sizes are related to the size of the geyser. The only time that our plumbers would deviate from the manufacturer recommendation is when the collector is not placed in an ideal position facing North or the tilt is far from the optimal. Then we would recommend a larger panel to improve the performance.
|Geyser Size||Solar Geyser Size|
|150 L||2.0 m²|
|200 L||2.5 m²|
|300 L||2 x 2.0 m²|
How much does a solar geyser save
This is the most important question. Why install a solar geyser if there is no long term saving. According to the manufacturer specifications, a 2.5 m2 collector installed on a 200L geyser will generate about 10kW (4.13kw x 2.5m2)of energy per day. At the current 2020 price of R2.50 per kilowatt, this amounts to a maximum of R 750 savings per month or R 9000 per year.
Flat Plate collector vs evacuated tube collector
A flat plate collector consists of a steel box with a glass cover and painted black on the inside to absorb heat. Copper tubes run though the box and absorb the heat. Evacuated tubes similarly allow heat to pass through and heat up the water inside, but the vacuum and larger glass surface area allow more heat to be absorbed than a similar sized flat plate collector
Advantages of the flat plate collector are the simplicity of design which means less could go wrong. The advantages of the evacuated tube collector is the superior performance. The flat plate collector is by far the most popular option.
Geyserwise Controller vs SR81 Controller
Both the geyserwise controller and the SR81 controllers perform the same basic functions. When the water in the collector is hotter than the geyser by a set amount 7 Degrees, then the controller starts the pump and transfers the hot water to the geyser. The controller also uses a timer and thermostat to measure the temperature in the geyser. If the temperature becomes too low, the controller will use an electrical element to maintain a minimum temperature.
The SR81 controller has additional functionality to the geyserwise controller, has a better display and also is more reliable as the geyserwise controllers fail regularly. Of course the superior SR81 controller is more expensive.
Do Geyser Timers Save money
There is little difference between adding heat continuously or adding heat at longer intervals to make up the heat losses. Having better control of the temperature in the geyser will save money. The temperature difference between the inside and outside of the geyser determines the rate at which energy is lost. So by using a geyser controller, the temperature can be set more accurately and at lower temperatures. We recommend 50 Degrees.
Standard geyser vs solar geyser design
There is a significant difference in design between a solar geyser and a standard geyser. The advantages of a solar geyser design is the shape which is shorter to reduce surface area and geyser heat loss. The solar geyser insulation is also upgraded to further reduce heat loss. The water inlet and water outlet ports on the solar geyser are positioned differently to aid the thermosiphon effect. This is of course only an advantage with a thermosiphon setup and not a pumped system
The advantage of a standard geyser is the price which is much lower due to the large volumes manufactured and installed. For split systems, standard geysers are the most popular choice
Pumped solar geyser vs thermosiphon solar geyser
Thermosiphon solar geysers are typically mounted on top of a roof, while pumped solar geyser systems are installed with the flat plate collector on top of the roof and the geyser hidden inside the roof or outside the building out of sight. Thermosiphon systems use natural heat convection caused by warm water rising from the collector to the geyser and cold water sinking from the geyser to the collector. A non-return valve and thermosiphon loops prevent the opposite action occurring at night and cooling the geyser. Pumped solar geysers use a small pump and controller to measure the temperature and move the water.
A collector mounted on a roof looks modern and is visually pleasing. A large geyser on the roof with pipework, frame work, insulation and valves is not visually appealing. For this reason most clients do not consider a thermosiphon geyser.
Retrofit solar geyser
All geysers can be retrofit with a collector and associated parts to start saving energy. Our experience with most insurance companies is that the insurance companies will pay out the clients a cash sum of money to the value of the burst geyser if the client states that the client wished to install a solar geyser.
Direct Solar Geyser vs Indirect Solar Geyser
Direct solar geyser systems are more efficient. Direct solar geysers are always installed in coastal regions where the temperature is moderated and never drops below zero.
Indirect solar geyser systems are necessary where the temperature drops below zero. When water freezes in the copper pipes, the pipes are stressed and could burst. In an indirect system, a mixture of glycol and water is used in a closed loop system that circulates through the geyser but does not mix with the geyser water.
Heat Pump vs Solar Geyser
A heat pump only uses 25% the energy of a normal electrical geyser. It does this by absorbing heat from the outside atmosphere and transferring it to the water. A split solar geyser has a small pump which consumes minimal electricity. A solar geyser has lower running costs and is less complicated. A heat pump is installed when solar geyser is not practical.
Heat Pump Sizing
|Geyser Size||Heating Capacity||Actual Power|
|150 L||3.5 kW||0.9 kW|
|200 L||5.5 kW||1.5 kW|
|300 L+||7.0 kW||1.85 kW|