Africa Energy Indaba

Solar Water Heating

Solar Water Heating

Available in direct/indirect systems

There are two main factors to consider when purchasing a solar water heating system; water quality and prevalence of frost in your area. Both factors are relevant to the type and performance of a solar water heating system best suited for your building.

There are two types of systems; a direct system and an indirect system:

1.) Direct System

In this system, the water is circulated and heated directly by the collector panels. To function properly, the ambient air temperature must not fall below 4˚C and the water quality must be good. The open/direct system is not generally suited to frosty winter conditions.

2.) Indirect System

In an indirect/closed system, the building water does not circulate through collector panels. Instead heat is transferred indirectly without coming into contact with the water supply via a heat exchange fluid in the collector panels (glycol). Ideally the collector panels and the tank should be situated on the roof right next to each other, resulting in minimal heat loss. Split systems are an option for those folk who do not want the tank exposed on their roof. The indirect/closed system is well suited to climatic conditions where frost is prevalent and the water quality is inconsistent.

Useful Information

Energy Savings

Estimated savings on energy bill : up to 75%

Estimated Costs

Estimated cost for system and installation: From R18000.00 upwards depending on your hot water needs.

Rebate Structure

There is no rebate currently in place at this point in time.

Price Comparison

The process of claiming a solar rebate has been streamlined and is facilitated by an independent auditing firm, with buyers receiving their rebates within 8 weeks of receipt of a complete application. Options such as leasing or paying off solar systems are now also available in the South African market. For your convenience, Green Building Africa provides a consulting service covering installation and rebate claim (South Africa only).

Payback Period

Between two to three years depending in hot water use.

Backup Element

A back up element (electrically powered) ensures the balance of supply and ensures that you never run out of hot water.

Pre-feed Installation

A pre-feed installation is recommended because it feeds solar heated water from the solar panels and storage tank to your existing geyser (hot water tank), capitalising on increased water storage capacity.

Heating Response

Evacuated tubes absorb 90% of the suns radiation and have a quicker heating response time.

Flat Panel Design

Flat panels absorb 75% of the suns radiation. The flat panel is not as effective in winter months.

Lifespan

Solar water geysers have a much longer lifespan (up to 20 years) than an ordinary geyser (usually 5 years).

Reliable On A Cloudy Day...

Heating still takes place on a cloudy day because the system relies on UV rays which penetrate clouds in overcast conditions.

Maintenance

Minimal maintenance is required

Water Delivery

Water can be delivered at boiling point but 60°C is all that is needed.

Available Capacity

150, 200, 250 and 300 litre size options are available. Size, number and choice is dependent on building hot water requirements.

Installation Optimisation

Ideally, the system should be installed in a northerly orientation on the roof.

Direct System - Installation Tips

In a direct system, where the geyser (hot water tank) and solar panel are installed separately from one another, they must not be more than 5 meters apart from one another.

Warranty & Quality

It is strongly advisable that you choose a system with SANS 1307, is SABS 400kPa approved and can be installed as a close coupled or split system. All Green Building Africa recommended suppliers have a warranty agreement on their products ranging from 5 years for locally manufactured systems to 10 years for imported systems.

Pre-approved Installation Companies (Required)

Many manufacturers/importers do not necessarily offer an installation service. Instead, manufacturers deal with the trade and recommend a pre-approved installation company. Make sure that the installations comply with SANS 10106 Solar Water Heater Installation Specifications and include all the required installation components (recommended for African countries as well).

Availability

There are an abundance of suppliers offering various product ranges and a SANS 10106 compliance installation service country wide.

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