Earth Notes: Glossary of Technical and Green Terms

Updated 2021-08-15.
Understand key words, abbreviations and other terms used on Earth Notes.
Definitions and explanations of important concepts, with links to further material both at this site and elsewhere.

What Is ...?

What is "LA (Lead-Acid battery)"?

battery 12V lead acid gel sealed 40AH on green grass lawn in sunshine for solar PV power generation and storage system 2 DHD 20210515 battery bank 12V lead acid sealed 4 gel 99Ah

A common type of battery with lead plates and a sulphuric acid electrolyte. Initially invented in the late 1800s. Used in many applications from cars and other motor vehicles through to electric vehicles, and storage for on-grid and off-grid renewable energy. Comes in common variants such as flooded, AGM and gel, and often in multiples of 12V. Very good support for chargers, solar controllers, etc. Lead-acid batteries generally do not take well to being discharged such that the SoC (State of Charge) is under 50% of full charge any significant amount.

Also known as:

  • lead-acid
  • Flooded Lead-Acid (FLA)
  • Advanced Glass Mat (AGM)
  • Sealed Lead-Acid (SLA, including gel and AGM)
  • gel
  • PbSO4

For more information see:

What is "LFP (Lithium Iron Phosphate)"?

battery 12V8 LiFePO4 20Ah prismatic new next to 12V lead acid gel sealed 40Ah older same usable capacity circa 250Wh 2 DHD

A Lithium-chemistry battery known for resistance to overheating and fires compared to Li-ion, at the cost of a slight reduction in energy density. All Lithium batteries need relatively careful management, eg with a BMS (Battery Management System), but are notably able to be discharged to a much lower SoC (State of Charge) than lead-acid batteries typically.

Also known as:

  • Lithium Iron Phosphate
  • LiFePO4

For more information see:

What is "MHRV (Mechanical Heat-Recovery Ventilation)"?

MHRV HR25H on tiled wall Vent Axia Lo Carbon Tempra in kitchen

A method to improve ventilation while retaining heat (or cool) in a building. In other words, achieve fresher air and lower energy bills. This is accomplished with a heat exchanger between in-flowing and out-flowing air, often a counter-current heat-exchanger. Sometimes the flows enter and exit the building via a central unit. With Single Room MHRV (SRMHRV or SRHRV) the mechanism exchanges air directly through an exterior wall in each equipped room.

Also known as:

  • MVRH (Mechanical Ventilation with Heat Recovery)
  • SRMHRV (Single Room Mechanical Heat-Recovery Ventilation)
  • SRHRV (Single Room Heat-Recovery Ventilation)
  • HRV (Heat Recovery Ventilation)
  • ERV (Energy Recovery Ventilation)

For more information see:

What is "PV (Solar Photovoltaics)"?

solar PV being installed at home solar PV polycrystalline poly CanadianSolar CS6P 255P ie 255W panel two being mounted with aluminium Al brackets to south facing garden wall as part of significant system rearrangement 7 DHD

Device or system to generate electricity from light, often sunlight, for example using solar panels on the roof of a building. Electricity produced by a solar PV system can be used locally, stored locally, or exported to an existing local grid, as determined by cost and technical factors. Solar PV comes in a number of forms, but common types are silicon monocrystalline, polycrystalline and amorphous.

Also known as:

  • solar power
  • solar panel
  • solar cell
  • monocrystalline PV
  • polycrystalline PV
  • amorphous PV

For more information see:

What is "VAWT (Vertical-Axis Wind Turbine)"?

turbine wind VAWT Darrieus commerical from QuietRevolution at E2 Energy Solutions Expo 2007 Olympia Kensington London England 1 DHD turbine wind small VAWT big box

A wind turbine, often for generating electricity, that spins around a vertical axis. Common designs of VAWT include Darrieus and Savonius. Compare with the more common HAWT (Horizontal-Axis Wind Turbine.

Also known as:

  • wind turbine
  • windmill
  • transverse axis wind turbine
  • cross-flow wind turbine

For more information see:

Other Glossaries

Please also consider visiting some of the external glossaries listed below, especially if you can't find the term that you need above.