Go Green Guys

Renewable Energy Solutions

Geyser Heating Options

Heatpumps

Heat pump technology is one of the cutting edge technologies when it comes to renewable energy water heating products. Even though this technology have been used in South Africa for heating water for many years, the recent increase in international demand have brought the component costs down, making the product extremely affordable for the residential and commercial users. Using refrigeration cycle to extract energy from the surrounding air (indirectly using solar energy) it can provide you with 60°C hot water day or night, winter or summer at a quarter of the cost of electrical geyser element heating.

Information:
Quiet operation with no solar collectors on the roof
Heat pumps are designed for low operating noise and can be installed anywhere around the house with adequate ventilation.

Class leading efficiency ensuring maximum saving
 Heat pumps will save you a lot of money each year due to your efficiency.

Can be used in conjunction with solar geysers
Solar geysers and Heat pumps can be used together to create a hybrid system which saves you money all year round.

Environmentally friendly
Heat pumps use the natural heat energy in the ambient air and can therefore reduce the green house gas emissions associated with the use of electricity.

Safe and reliable
Heat pumps have been designed to boast many safety features hence ensuring reliable & safe operation for many years.

Fully automated anti freeze function
Heat pumps can operate in sub-zero temperatures as they can defrost themselves automatically with their build in program protection.

Costs and savings

Costs

The Installation of a typical heatpump system costs around R16500 depending on the size of the geyser. Running costs will vary depending on a number of factors including the size of your geyser, how well insulated it is and what temperature you set the geyser to heat to.

Savings

How much you can save will depend on what system you use now, as well as what you are replacing it with. Your savings will be affected by:

  • Your old heating system. If your old heating system was inefficient, you are more likely to see lower running costs with a new heat pump.
  • Water heating. If the heat pump is providing hot water then this could limit the overall efficiency. You might want to consider solar water heating to provide hot water in the summer and help keep your heat pump efficiency up.

Using controls. Learn how to control the system so you can get the most out of it. You will probably need to set the heating to come on for longer hours, but you might be able to set the thermostat lower and still feel comfortable. Your installer should explain to you how to control the system so you can use it most effectively.


Evacuated tubes and flat plate collectors.


Flat plate collector
A flat-plate solar collector is one of two main types of solar collectors, which are key components of a solar water heating systems. The other type is an evacuated tube collector which we will discuss later.

Flat-plate collectors are the most common solar collectors for use in solar water-heating systems in homes. A flat-plate collector consists of an insulated metal box with a glass or plastic cover (the glazing) and a dark-coloured absorber plate.
Solar radiation is absorbed by the absorber plate and transferred to a fluid that circulates through the collector in tubes.

Flat-plate collectors heat the circulating fluid to a temperature considerably less than that of the boiling point of water and are best suited to applications where the demand temperature is 30-70°C and/or for applications that require heat during the winter months.

Flat collectors can be mounted in a variety of ways, depending on the type of building, application, and size of collector. Options include mounting on a roof or free-standing.



Evacuated Tubes option

This system comprises a series of cylindrical glass tubes are attached to a frame and installed on top of a roof. Each tube is approx 1.9m long and inside each tube is a copper rod which extends from the bottom to the top of the tube and then into a manifold. A special chemical formula (glycol based) inside each tube starts to boil between 30 and 40 degrees Celsius. This quickly heats up the copper rods in each tube which in turns heats the water which passes through the manifold. The manifold in turn is connected to a geyser through a pump and differential solar controller.

The vacuum inside of the evacuated tube collectors have been proven to last more than 25 years, the reflective coating for the design is encapsulated in the vacuum inside of the tube, which will not degrade until the vacuum is lost. The vacuum that surrounds the outside of the tube greatly reduces convection and conduction heat loss, therefore achieving greater efficiency than flat-plate collectors, especially in colder conditions. The high temperatures that can occur may require special design to prevent overheating.

Evac Vs Flat PlatePeople often ask us what’s the difference between the 2 systems.Flat-plate collectors usually lose more heat to the environment than evacuated tubes due to their construction and design. They are inappropriate for high temperature applications such as process steam production. Evacuated tube collectors have a lower absorber plate area to gross area ratio (typically 60–80% of gross area) compared to flat plates. Based on absorber plate area, most evacuated tube systems are more efficient per square meter than equivalent flat plate systems. This makes them suitable where roof space is limiting, for example where the number of occupants of a building is higher than the number of square metres of suitable and available roof space. In general, per installed square metre, evacuated tubes deliver marginally more energy when the ambient temperature is low (e.g. during winter) or when the sky is overcast. However even in areas without much sunshine and solar heat, some low cost flat plate collectors can be more cost efficient than evacuated tube collectors. Although several European companies manufacture evacuated tube collectors, the evacuated tube market is dominated by manufacturers in the East. Several Chinese companies have track records of 15–30 years. There is no unambiguous evidence that the two designs differ in long term reliability. However, evacuated tube technology is younger and (especially for newer variants with sealed heat pipes) still need to demonstrate competitive lifetimes. The modularity of evacuated tubes can be advantageous in terms of extensibility and maintenance, for example if the vacuum in one tube diminishes.For a given absorber area, evacuated tubes can therefore maintain their efficiency over a wide range of ambient temperatures and heating requirements. In most climates, flat-plate collectors will generally be more cost-effective than evacuated tubes.

For a given absorber area, evacuated tubes can therefore maintain their efficiency over a wide range of ambient temperatures and heating requirements. In most climates, flat-plate collectors will generally be more cost-effective than evacuated tubes.

Accredited installers for ITS Solar and Firefly