Wheels or caterpillars

a wheel

a caterpillar

a rocket

off road

the snow

a swamp

a tank

the space

to build

functional specifications


a bulldozer

the weight

the load



the power


a Trench

to climb

a manager

a groomer

a team

to design

an engineer

to convince

the floor

a kind of

a proposal


Sustainable development - Geothermal energy

the geothermal systems

the heat

the geothermal pump

the pipes

a cycle

the earth

the frost line


a degree

a degree Fahrenheit

a colder air

a heat exchanger.

a warm air

the solar power

the underground

Ground Loops

A ground loop is the mechanism by which a geothermal system gathers the heat from the ground and delivers it to the building (heating cycle) or takes the heat from the building and releases it into the ground (cooling cycle)

Heat Pumps

A heat pump is nothing more than a refrigeration unit and contains the same basic components found in a refrigerator



Sustainable development - Hydropower systems


a system

to flow

to produce

the mechanical energy



the ways

to produce energy

to require

a large storage reservoirs

the direct current (DC)

the hydro turbine

the alternating current (AC)

Cavitation :

Noise or vibration causing damage to the turbine blades as a results of bubbles that form in the water as it goes through the turbine.

Draft tube :

a water conduit, which can be straight or curved depending upon the turbine installation,


Vertical change in elevation, expressed in either feet or meters, between the head water level and the tail water level.

Flow :

 volume of water, expressed as cubic feet or cubic meters per second, passing a point in a given amount of time.

Headwater :

the water level above the powerhouse.

Low Head :

Head of 66 feet or less.


the rotating part of the turbine that converts the energy of falling water into mechanical energy.

Scroll case

a spiral-shaped steel intake guiding the flow into the wicket gates located just prior to the turbine.

Small hydro

Projects that produce 30 MW or less.


the channel that carries water away from a dam.


the water downstream of the powerhouse.

Ultra low head

Head of 10 feet or less.

Wicket gates

adjustable elements that control the flow of water to the turbine passage.

Penstock :

a closed conduit or pipe for conducting water to the powerhouse.


Sustainable development - Solar cells system

a solar cells photovoltaic cell

a light energy

a moving parts




the emission free

a suitable

a wavelength

a hit

a photovoltaic cell

the silicon

to convert

to transfer

a function

the photo generation

the electrical energy

the photovoltaic effect.

the field of technology

the sunlight

the carriers

the electron

the light-absorbing material

the solar modules

the photovoltaic arrays

the grid

to generate

a device

the renewable energy :

Particularly useful in situations where electrical power from the grid is unavailable such as in remote area power systems, Earth-orbiting satellites and space probes, remote radiotelephones and water pumping applications.



Sustainable development - Solar water heater

a solar cells

a solar panel

a solar energy

the emission free

a suitable

a wavelength

a hit

to convert

to transfer

a device

a function

the field of technology

the sunlight

the carriers

a solar water heater

a solar collector

a storage tank

solar absorber

a double walled jacket

thermosiphonic flow

to be induced

a solar radiation

a valve

a liquid which vapourises at a

prescribed temperature

the light-absorbing material

the solar modules

the renewable energy :


Solar heating systems are generally composed of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir or tank for heat storage and subsequent use. the systems may be used to heat domestic hot water, swimming pool water, or for space heating.



Sustainable development - Wind turbine

an anemometer

a blade

the wind speed

a controller

a turbine blade

a brake

a rotor





a disc brake

a gear box

a miles per hour

a rotation per minute

a shaft

a rotational speed

a generator

the high-speed shaft

the low-speed shaft

a nacelle


the hub

the yaw drive

to applie

to blow

to damage

to require

to rotate

to stop

tubular steel