Glossary

001. AC – Alternating current. Electrical energy reverses its direction at regular intervals, typically 60 Hertz. 

002. Ampere or Amp – Electric current is measured in amperes or amps.

003. Array (Solar Array) – A group of solar modules connected together.

004. Battery Bank – A group of batteries wired together to store power in a solar electric system. Allows energy to be used at night, on cloudy days, or to use more power than the array can produce at one time.

005. Centrifugal Pump – A pump that utilizes rotating impellers to accelerate water upward.

006. Controller – This converts the power from the solar array in a specific voltage/current configuration to a voltage/current configuration more efficiently utilized by the pump.

007. Current – The rate of flow of an electric charge. Current is measured in amperes or amps.

008. Current Booster – A controller function that converts a given voltage & current output from the array to a more practical configuration for the pump, typically providing more current but nearly equal power.

009. Diaphragm Pump – A positive displacement pump that utilizes a camshaft causing piston displacement. A flexible elastomer (diaphragm) acts as a cam and piston assembly sealing mechanism.

010. DC – Direct current. Electrical energy flows in one direction and is of substantially constant value.

011. Drawdown – The distance or depth the standing water level lowers when water is pumped from the well at a given rate.

012. Elevation – Vertical distance from the ground to the input level of a tank or other means of storage.

013. Flow Rate – Volume of water provided per second, minute, hour, or day.

014. Friction Loss – Pressure loss due to a pipe’s resistance to water flow.

015. GPM – Acronym for gallons per minute, used to measure the water flow rate.

016. Ground Mount – A fixed array mounting method for solar modules with multiple connections to the earth.

017. Inverter – An appliance used to convert independent DC power into AC power.

018. Kilowatt or kW – Unit of measurement reflecting 1,000 Watts (See Watts).

019. Line Loss – Power loss across a length of wire. Depending on its size, copper wire has a specified resistance per foot. The wire is then adequately sized to meet a fixed line loss (typically 3% – 5%).

020. LPM – Acronym for liters per minute, used to measure the water flow rate.

021. Solar Module – A collection of solar cells that are connected, physically and electrically, is held together by a frame and covered by a protective surface such as glass; the term is used interchangeably with the solar (electric) panel.

022. Mounting Angle – Angle of the array, as measured horizontally.

023. Parallel Wiring – A wiring system for solar electric panels or batteries increases the amperage of a given array. Parallel wiring is “+” to “+” (positive to positive) and “-” to “-” (negative to negative).

024. Photovoltaic (PV) – Photovoltaic essentially means to convert light into electricity. This is often referred to as PV, for short.

025. Pole Mount – A stationary pole-top solar array mounting method, where the solar panels are affixed atop a pole instead of a ground-mounted array.

026. PSI – Pounds per square inch, a unit of measurement for pressure.

027. Sand Shroud – An apparatus that “shrouds” the pump (using a collar and section of large diameter pipe) to ensure input water enters the pump from below so that sand and sediment are no longer entrained in the input water.

028. Series Wiring – A wiring system for solar modules or batteries that increases the voltage. Series wiring is “+” to “-” (positive to negative).

029. Solar Cell – The smallest basic solar electric device generates electricity when exposed to light. Typical solar modules are comprised of 30-72 solar cells wired in series but depend on the specified requirements.

030. Solar Electric – The preferred term used to describe something which uses sunlight to produce electricity.

031. Standing Water Level – The distance from the top of the well to the surface of the well when no water is being pumped.

032. Sun Hours on Tilt (SHOT) – The number of sun hours at a given angle from the horizon (on average).

033. System Grounding – A means of electrically connecting a photovoltaic system to the ground.

034. Tank Pressure – For pressurized systems, the pressure of a tank is in psi or kpa.

035. Total Dynamic Head – A means of expressing a load of a pumping system at a given flow rate in terms of its equivalent vertical column of water (i.e., vertical lift and friction converted to vertical lift).

036. Accurate Maximum Power Point Tracking (MPPT) – A feature of the pump controller that ensures the solar array operates at its maximum power point.

037. Voltage or Volts – Voltage is the amount of electrical pressure which causes electricity to flow in the power line. If electricity were water, the voltage would measure pressure at the faucet.

038. Watts – A watt is a measurement of total electrical power. Volts x Amps = Watts

039. Watt Hour – The quantity of electrical energy used or produced when one Watt is used for one hour.

040. Solar Noon – The point of time in a day when the sun is at its highest point in the sky. This does not regularly correspond to midday due to variations in time zones and the tilt of the earth’s rotational axis.

041. Solar Source – The amount of sunlight available to a solar system, which is affected by the location, tilt and orientation of solar modules as well as by any shading they experience at the site.

042. Solstice – The times of the year when the sun’s altitude is at an extreme: the summer solstice occurs when the sun at solar noon is at its highest; the winter solstice occurs when the sun at solar noon is at its lowest. In the Southern Hemisphere, the winter solstice occurs in June, and the summer solstice occurs in December.

043. Standard Testing Conditions – Operating conditions, where the cell temperature is 25°C, irradiance is 1,000W/m², and air mass are 1.5. Ratings of a solar module on a datasheet are generally based on ratings achieved under STC.

044. Vertical Lift – The vertical distance from the ground to the output of the pumping system.

045. Watt-peak – The unit of measurement for the rated power of a PV module.

046. Yield – The amount of energy generated by a PV system over a period of time.

047. Solar Altitude – The angle between the sun and the horizon (always between 0° and 90°).

048. Rated Power – The amount of power a module is able to produce under standard test conditions.

049. PV System – The solar modules and all associated equipment required to make it work.

050. Peak Sun Hours – The number of PSH for the day indicates the amount of solar radiation received in an area of one square meter, equivalent to the number of hours for which power at 1kW/m² is received.

051. Over-current protection – A device that disconnects the system in the event of excessive current levels.

052. Multi-mode Inverter – An inverter that is able to operate when it is connected to the grid as well as when it is disconnected from the grid.

053. Mounting System – Hardware that secures the solar PV modules to a rooftop or the ground.

054. Solar Radiation – The total amount of solar radiation energy available per unit area over a specified period; the sum of irradiance over a time period, often measured in kWh/m²/yr or MJ/m²/day.

055. Irradiance – The total amount of solar radiation available shown as power per unit area, measured in W/m².

056. Ground Mounting – A mounting method for solar PV modules.

057. Fuse – An electrical protection device that opens a circuit under fault conditions, i.e., when there is too much current. A fuse opens the circuit by melting and must be replaced to re-close the circuit.

058. Equinox – The time of year when the sun is at its average altitude and the lengths of day and night are equal. There are two equinoxes each year: one in March and one in September.

059. Energy Efficiency – Using either passive or active practices to reduce the amount of energy used.

060. Electricity Grid – The electricity distribution network: the poles and wires that deliver electricity from power plants to households (also known as the ‘grid’ or the ‘power grid’).

061. Earthing – An electrical safety concept that prevents people from being electrocuted by providing a low-resistance path along which electricity can flow harmlessly to the ground if there is a fault.

062. Conversion Efficiency – The proportion of energy in sunlight that is converted by a PV module into electrical energy, expressed as a percentage (also known as the efficiency of the module).

063. Circuit Breaker – An electrical protection device that can open an electrical circuit under fault conditions, such as when there is too much current. A circuit breaker that closes the circuit again can be guided to reset.

064. Air Mass – The volume of air, defined by its temperature and water vapour content.