Glossary of Terms





Renewable Energy Target: “The RET scheme is designed to deliver on the Australian Government’s commitment to ensure that the equivalent of at least 20% of Australia’s electricity comes from renewable sources by 2020. The RET will help to speed up the adoption of renewable energy technologies and help smooth the transition to a clean energy future”. Source:


Renewable Energy Certificates. The term given to tradable commodities that can be generated by the installation of renewable energy sources. The Australian Government has implemented the scheme to incentivise the growth in the development of large-scale and small-scale systems.


Small-scale Technology Certificates: Small-scale Technology Certificates are a type of renewable energy certificate that can be generated with the installation of small-scale renewable energy systems such as residential solar panels, solar water heaters and heat pumps.


Large-scale Generation Certificates:  Large-scale Generation Certificates are a type of renewable energy certificate that can be generated with the installation of large-scale renewable energy systems such as solar power stations and wind power generators.

Carbon Footprint

Refers to the total volume of greenhouse gases produced to directly and indirectly support human activities. A carbon footprint can relate specifically to a residence, a business, a commercial activity or a geographical area. A carbon footprint is generally expressed as “equivalent tons of carbon dioxide (CO2)”.

Greenhouse Gas

Greenhouse gases absorb and emit radiation within the thermal infrared range of our atmosphere. Carbon dioxide is one form of a greenhouse gas. Since the beginning of the industrial revolution, the burning of fossil fuels has contributed to the increase in carbon dioxide in the atmosphere, which is believed to be leading to global warming. Source: Wikipedia entry.

CEC Solar PV Accreditation

To be eligible for government incentives such as RECs, solar credits and feed-in tariffs the installer must be accredited by the Clean Energy Council. Solar PV accreditation is a qualification from the Clean Energy Council that demonstrates competence in design and/or installation of solar power systems.

Purchased Energy

Refers to the energy that consumers buy from a power retailer for use around the home or business. Examples: Electricity and gas.

Solar Hot Water



Solar Water Heater / Solar Hot Water System

A system that produces hot water using thermal energy obtained from the sun or environment

Heat Energy

Heat energy is a form of energy which transfers among particles in a substance (or system) by means of kinetic energy of those particles. In other words, kinetic theory suggests, the heat is transferred by the friction of particles bouncing into each other. Source:


A system using more than one type of technology

Solar Gain

Refers to the increase in temperature on a structure or object due to solar radiation. The greater the strength of the solar radiation, the greater the solar gain by an object. Solar hot water thermal collectors are designed for optimal solar gain to maximise the efficiency of the water heating process.

Solar Pre-heat

Refers to the pre-heating of a water supply using thermal solar collectors. This water can then be stored for later use reducing the amount of energy required to heat the water from ground temperature.

Solar Collector

A specially engineered panel or collector where the fluid passes through copper tubes and where it is heated by solar energy.

Storage Tank

An insulated water tank specially designed for the storage of heated water


The automatic circulation of waters of different temperatures. As fluid is heated it becomes less dense (lighter) and rises, as it becomes colder it becomes denser (heavier) and falls causing thermosiphoning. Thermosiphon solar water heaters are often referred to as “close-coupled” and do not require electric pumps to circulate the water.

Pumped System

Refers to a “pumped” or “split” solar hot water system that uses a small pump to circulate water up to a series of roof-mounted solar collectors for heating. 

Absorber Plate

The part of the collector that collects the solar energy and transforms it to heat. The absorber plate is treated with a special coating, designed to attract and retain the heat energy from the sun.

Selective Surface

Refers to the special treatment given to the surface of a thermal collector absorber plate, allowing it collect the optimum amount of heat energy from the sun.


A supplementary heat source in a solar hot water or solar pre-heat system; typically electricity or gas.

Continuous Flow Gas Water Heater

A gas fuelled water heater that only ignites to heat ‘on demand’, as the water flows through it.

Heat Exchanger

A heat exchanger is a piece of equipment designed for the efficient heat transfer from one medium to another. Heat exchangers are often used in areas of poor water quality of where multiple heat sources are required.

Close-coupled Solar Hot Water

Refers to thermosiphon system where a collector is closely mounted to the hot water storage tank.

Closed loop

Refers to a system using a heat exchange fluid to heat the potable water via a heat exchanger. In these systems there is no mixing of fluids between the heat source and the heated water. Can be either a thermosiphon or pumped system.

Open Loop

Refers to a system where the potable water is in direct contact with the thermal collector and water storage tank. Can be either a thermosiphon or pumped system.

Solar (Differential) Controller

An electrical device that reads the difference between the Collector
temperature and the stored water temperature, to regulate the solar
input by controlling the pump operation in a split system.


A thermostatically controlled electrical element used to heat the stored water above the level of solar contribution.

Hard Water

A term given to water that contains high levels of minerals such as calcium carbonate, magnesium carbonate & bicarbonates. Hard water may also be known to be said to be high in Calcium Hardness. Hard water can cause corrosion in and around surfaces, particularly on materials such as water pipes.

Glycol (Heat Exchange Fluid

Transfers the solar energy to the stored potable water via a heat exchanger, prevents freezing or clogging of collectors in bad water areas.


Solar Power



Solar Module or Cell

Refers to an electrical device known as a photovoltaic (PV) cell that converts light energy in to electricity using a photovoltaic effect. A collection of solar cells/modules can also be connected to produce a solar panel.  

Solar Panel

A panel containing multiple solar modules, designed to convert a higher amount solar energy into electrical energy. These panels are typically rectangular in shape and designed for fixing a solar power system to a frame or building.

Solar Array

A collection of panels

Monocrystalline panels

Solar panels that consist of cells made from monocrystalline or a single piece of silicone wafer.

String of Panels

Refers to a set of solar panels connected in electrical ‘Series’ or ‘Parallel’ to reach a higher voltage and current. Some solar panel systems require more than one string of panels, especially if the panels must cover multiple sections of roof. A MPPT inverter or multiple inverters are required if multiple roof aspects are to be used.


An electronic device designed to convert DC electricity to AC. It is commonly seen in the form of a box which is situated on the wall of a house.

AC Power

Electricity using Alternating Current. For example the mains power into your house where the signal looks like a wave.

DC Power

Electricity using Direct Current like the power delivered from a battery. The signal looks like a straight line above referenced above ground

Kilowatt (kW)

1 kW = 1,000 watts.
A watt is a unit of measuring power.

Kilowatt-hour (kWh)

Refers to 1 kilowatt of electricity supplied over 1 hour or the amount of kW produced for a given time period.

Megawatt-hour (mWh)

Refers to 1000 kilowatt of electricity supplied over 1 hour or the amount of kW’s produced for a given time period.

Grid-connected Solar

Where a solar power system is wired to the electrical supply network so that any excess power may flow back into it.

The “Grid”

The poles and wires forming a city’s electrical supply network


A device that  records the movement of electricity into a home or building

Bi-directional meter

A bi-directional meter is a device that allows the flow of electricity in and out of the home and records the movement in both directions

Smart Meter

A digital device that measures and records how much electricity is being used by a home or business. Smart meters are designed to be accessed by power distributors via the power lines to the property and are able to record the power consumption used over smaller time periods as a result.

Feed-in Tariff

This is the price that a power company pays for excess power sent back into the network (grid).