Glossary
Glossary
Ever wondered what's the difference between a solar water heating system and solar photovoltaic? Our glossary below aims to help answer some of your questions. If you have more in-depth queries please phone 01382 501730 to arrange a visit.
Heat can escape from your home through inadequately sealed windows or doors, through letterboxes or even cracks or gaps surrounding pipes leading outside.You may find a lot of your home heating costs in money and carbon are spent on heat loss rather than gain so a bit of DIY is well worth sorting before you proceed with other measures.
Insulation
Insulation is the term used to describe the installation of some type of barrier used to keep heat from escaping from your property. Insulation can be used in the loft, in the walls for cavity wall, or if your home has solid walls as internal or external wall insulation. Underfloor insulation is effective too. There are many different insulating products to choose from, depending on what surface or structure you are working on, and these can be as diverse as pulped paper and recycled plastic bottles. At Sun City House, we have a range of examples for you to view. Just call us on 01382 501730 to arrange a visit.
Solid Wall
Sempatap (for internal wall insulation). If you have a wall which is not suitable for cavity wall insulation it may be suitable for using Sempatap. This goes on like wallpaper and can be decorated after, it can also be used on ceilings if you are unable to use loft insulation. Solar Cities offer a set price per roll using the supplier Mould Growth Consultants. We can send you a sample as well as an information leaflet and a dvd which explains how to put it up yourself, or you can ask someone who is good at wallpapering. See our special deal with MGC here.
SolarPhotovoltaics (PV)
Solar photovoltaics (PVs) convert energy from daylight into
electricity using a semiconductor material such as silicon. When
light hits the semiconductor, the energy in the light is absorbed,
'exciting' the electrons in the semiconductor so that they break
free from their atoms. This allows the electrons to flow through
the semiconductor material (in a similar manner to a normal
electrical circuit) producing electricity.
There are a number of PV technologies, including polycrystalline,
monocrystalline and thin-film. Solar PV cells can be arranged in
panels on a building's roof or walls, and can often directly feed
electricity into the building. With the latest PV technology, cells
can also be integrated into the roof tiles themselves. Solar PV
cells can be used in both stand-alone and grid-connected
systems.
Dundee's Morgan Academy has a 10.5kWp PV array on its roof which
generates electricity to power the schools ground source heat
pumps.
Solar WaterHeating System
Solar water heating uses collectors, usually on the roof of a
building, to capture and store the sun's heat via water storage
systems. The collectors provide heat to a fluid that circulates to
a water tank. The heat is primarily used for heating water in
domestic dwellings, industrial facilities and commercial buildings.
This includes the growing market for solar swimming pool
heaters.
An example of the largest (equal) solar water heating system in
Scotland can be seen at St Johns High School in Dundee where it
heats the swimming pool.
Heat Pump
Heat pumps are electrically powered systems that tap the stored energy of the ground, water or air. The systems use the external environment's relatively constant temperature to provide heating and hot water (and sometimes cooling) for buildings and industrial processes. Heat pumps operate on the same principle as a domestic fridge but instead of extracting heat from the food in a fridge and expelling it into the room, heat pumps extract heat from outside and, in effect, concentrate it, delivering useful heat to the building.
Ground Source Heat Pump
Heat pumps can be very energy efficient, producing four or five
times the amount of heat energy for every unit of electrical energy
needed. A heat pump takes the heat from a refrigerant fluid (or
water) that is in contact with the ground, extracts the heat from
this source and transfers it to a heat sink where it can then be
circulated through a heating system. Although the refrigerant fluid
is cooled by this process, it can be re-circulated back through the
ground where it will absorb more heat before being passed through
the heat pump again.
Dundee's Morgan Academy uses ground and air source heat pumps to
provide space heating and cooling in the assembly hall area of the
school.
Ground-source heat pumps require some electricity to extract and
make use of low-grade heat. However, there is no reason why this
electricity could not be generated by another form of renewable
energy.
Wood Pellet Stove/Boiler
Wood pellets (small compressed sawdust pellets) can be used to
fuel stoves (with or without back boilers) and pellet burning
boilers especially designed for the purpose. Pellet stoves require
less attention compared to log appliances and are the most
convenient wood fuel to use in a domestic setting. Integral fuel
hoppers store enough pellets for 1 to 3 days operation and the ash
pan would only need emptied once a month or once a year depending
on use. Wood pellet boilers are fully automatic and almost as
convenient as using gas or oil. They are well suited to meet
variable load demands and can be operated on a timer. Pellet stoves
and boilers operate at high efficiencies of around 90%. Being a
very dense fuel pellets require less storage space than logs or
chips.
At present only pellet stoves and boilers exempted for use in
Smoke Control Areas can be installed in Dundee. Contact us for more
information.
Wood Chip Boiler
As with wood pellets modern wood chip boilers can provide a high
level of automation and convenience for wood fuelled space heating.
Wood chip systems generally have an output of greater than 20 kW
(suitable for a large farmhouse or larger) so are not cost
effective or appropriate for typical domestic scale applications.
Extensive fuel handling systems and fuel storage facilities are
required for automated operation. It is important to be able to
source a steady supply of woodchip with a consistent size and
moisture content suitable for burning in a boiler, as not all chips
are suitable for burning.
At present only wood chip boilers exempted for use in Smoke
Control Areas can be installed in Dundee. Contact us for more
information.
Biomass (Wood) Heating System
Wood is a very versatile fuel and can be burned in many
different forms to provide central heating. Until recently wood
fuelled heating has had the drawback of a lack of controllability.
Automatic wood fuelled boilers, and many stoves, overcome this
problem by utilising thermostats which automatically control fuel
and air intake with very responsive and programmable temperature
settings.
See wood chip boiler and wood pellet boiler and stove entries for
more detail.
Wind Turbine
The use of wind as a renewable energy resource involves
harnessing the power contained in moving air. Wind represents a
vast source of energy that has already been harnessed for hundreds
of years. The UK has the largest potential wind energy resource in
Europe and wind power is currently one of the most developed and
cost-effective renewable energy technologies. Wind turbines can be
situated either onshore or offshore. Small wind turbines designed
to be integrated into buildings are also becoming commercially
available.
Dundee has Europe's largest urban wind turbines sited at the
Michelin Tyre factory in the city.
Hydro Electric Turbine
Hydroelectric power is the energy derived from flowing water in
rivers or from man-made installations where water flows from a
high-level reservoir down through a tunnel and away from the dam.
Water power was used for centuries to power machinery, for example
for grinding corn or in mills and factories, but was largely
replaced by steam power in the Industrial Revolution. Water power
is now mainly used to generate electrical energy.
Turbines placed within the flow of water extract its kinetic
energy and convert it to mechanical energy. This causes the
turbines to rotate at high speed. The turbines drive a generator
that converts the mechanical energy into electrical energy. The
amount of hydroelectric power that can be generated is related to
the water flow and the vertical distance (known as 'head') through
which the water has fallen.
In the smallest hydroelectric schemes, the head of water can be a
few metres; in larger schemes, the power station that houses the
turbines is often hundreds of metres below the reservoir.
Hydroelectric systems can be connected to the main electricity
grid, or can be part of a stand-alone power system. In a
grid-connected system, any electricity generated in excess of
consumption on site can be 'sold' to electricity companies. In an
off-grid hydroelectric system, electricity can be supplied directly
to the user or via a battery bank.
Marine Energy Device
Marine energy usually refers to wave and tidal power. Both wave
energy and tidal power involve harnessing the movement and energy
contained in the ocean and converting it into electrical
power.
Wave Energy - as ocean waves are created by the interaction of
wind with the surface of the sea, waves have the potential to
provide an unlimited source of renewable energy. Wave energy can be
extracted and converted into electricity by wave power machines.
They can be deployed either on the shoreline or in deeper waters
offshore.
Tidal Power - this exploits the natural ebb and flow of coastal
tidal waters caused principally by the interaction of the
gravitational fields of the earth, moon and sun. The coastal water
level fluctuates twice daily, alternatively filling and emptying
natural basins along the shoreline. The currents flowing in and out
of these basins can be exploited to turn mechanical devices to
produce electricity. A variant of tidal energy is tidal stream (or
marine current) technology. Tidal streams are fast sea currents
created by the tides, often magnified by topographical features,
such as headlands, inlets and straits, or by the shape of the
seabed when water is forced through narrow channels.
FITS ( Feed in Tarrifs )
FITS (Feed-in tariff) is an advanced renewable tariff or renewable energy payment. This is a policy mechanism designed to accelerate investment in renewable energy technologies. It achieves this by offering long-term contracts to renewable energy producers, typically based on the cost of generation of each technology. Technologies such as wind power, for instance, are awarded a lower per-kWh price, while technologies such as solar PV and tidal power are offered a higher price, reflecting higher costs.
The goal of feed-in tariffs is to offer cost-based compensation to renewable energy producers, providing the price certainty and long-term contracts that help finance renewable energy investments.
Currently the feed in tariff for solar pv is 21p per kWh as of the 3rd of March 2012. You can find out about the new FITS scheme from April onwards at DECC
Wind Turbine
The use of wind as a renewable energy resource involves harnessing the power contained in moving air. Wind represents a vast source of energy that has already been harnessed for hundreds of years. The UK has the largest potential wind energy resource in Europe and wind power is currently one of the most developed and cost-effective renewable energy technologies. Wind turbines can be situated either onshore or offshore. Small wind turbines designed to be integrated into buildings are also becoming commercially available.
Solar Water Heating System
Solar water heating uses collectors, usually on the roof
of a building, to capture and store the sun's heat via water
storage systems. The collectors provide heat to a fluid that
circulates to a water tank. The heat is primarily used for heating
water in domestic dwellings, industrial facilities and commercial
buildings. This includes the growing market for solar swimming pool
heaters.
An example of the largest (equal) solar water heating system
in Scotland can be seen at St Johns High School in Dundee where it
heats the swimming pool.
Student Green Challenge
Simple ways that you and your flatmates can help the environment. Sign up today or Login
What is the Student Green Challenge?
Community Carbon Exchange
Helping schools, community groups and businesses to save carbon (and money) through simple, fun actions. Lead the way for your community by signing up today or Login !
What is CCX?
Solar Cities Scotland is a registered Scottish charity (SC 037308) and a company limited by guarantee (SC 297817)