Alternative Energy Glossary

Interseasonal Heat Transfer

Interseasonal Heat Transfer is a new form of on site renewable energy that combines the merits of solar thermal collection in summer with heat storage in ThermalBanks to double the efficiency and Coefficient of Performance of ground source heat pumps in winter.

Interseasonal Heat Transfer captures surplus heat from summer sunshine, stores it in ThermalBanks™ in the ground and releases it to heat buildings in winter.

Interseasonal Heat Transfer also captures cold on winter nights, stores this in ThermalBanks™ in the ground and releases it to cool buildings in summer.

An IHT system includes an Asphalt Solar Collector, a ThermalBank to store heat energy, a heat pump and a smart control system.

ThermalBank

A ThermalBank is a bank of earth used to store heat over time. Alternative descriptions include: Heat Bank, Heat Battery, Heat Store, Heat Vault, Underground Energy Storage, interseasonal heat store, interseasonal energy storage, Underground Thermal Energy Storage ("UTES").

Solar Road System

An ICAX Solar Road System is a road which captures solar heat in summer, stores the heat in a ThermalBank until it is needed to prevent the road freezing in winter. A Solar Road System can save lives. It also cuts out the need for salting of roads and prolongs the life of the road by reducing extremes of temperature in summer and in winter.

Solar Collector

A Solar Collector collects heat from the sun. Flat plate or evacuated tube solar thermal panels are generally roof mounted and can be an efficient means of providing domestic hot water (DHW). However, without significant heat storage capacity the heat collected may not be fully used. ICAX designed Asphalt Solar Collectors as an efficient means of collecting a large amount of heat over the summer months for storage in ThermalBanks and use for space heating in winter. Alternative names include: Playground collector, Road Collector, Hot Roads, Solar Roads.

Heat Pump

A Heat Pump is a machine working on the Carnot cycle which transfers heat from a heat source to a heat sink. A refrigerator uses a heat pump to move heat out of a fridge. An industrial heat pump can be used to move heat from an external source into a building.

Ground Source Heat Pump

A Ground Source Heat Pump ("GSHP") is used to extract heat from the ground and transfer it into a building to provide space heating. Alternative names include: Ground Coupled Heat Pumps, Earth Energy Systems, Geoexchange Heat Pumps, Ground collector heat pumps, Geothermal heat pumps.

GSHPs are now established technology with over a million installations (largely in North America, Sweden, Switzerland and Germany). GSHPs are emission free at the point of use and need no flue or chimney. A GSHP can achieve a coefficient of performance of 4 if used in conjunction with a low temperature delivery system like underfloor heating.

An ordinary GSHP can compete economically with conventional oil fired heating or electric storage heating. Gas fired heating may be cheaper than an ordinary GSHP installation, although a GSHP will have lower CO2 emissions.

It is possible to double the CoP of a GSHP if used with an ICAX ThermalBank. A full Interseasonal Heat Transfer System (incorporating a solar collector, ThermalBank and GSHP) can show a lower annual heating cost than a gas fired boiler and can save over 50% of carbon emissions compared to a gas fired boiler. Using IHT is the key to energy savings in buildings.

In addition, IHT can provide "Free Cooling" to extract some heat from buildings a very little cost, or active cooling using the principles of IHT in reverse.

Air Source Heat Pump

An Air Source Heat Pump ("ASHP") is used to extract heat from the air and transfer it into a building to provide space heating. As no ground works are involved, an ASHP installation will generally have a lower capital cost than a GSHP, but a higher running cost for winter heating.

Ground Water Source Heat Pump

A Ground Water Source Heat Pump ("GWSHP") is used to extract heat from ground water and transfer it into a building to provide space heating.

Underfloor heating

Underfloor heating ("UFH") is an efficient method of distributing heat into a building to provide comfortable space heating. Lower temperatures (around 40°C) can be distributed over a larger area than the higher temperatures (around 70°C) needed for wall mounted radiators. Underfloor heating is invisible and clutter-free and radiates heat gently from ground level to avoid the convection and heat losses generated by wall mounted radiators. Underfloor heating makes a good match for distributing heat from a ground source heat pump - because a GSHP will deliver a higher coefficient of performance if a lower delivery temperature can be used.

The underfloor piping can also be used to extract heat from the building in summer by circulating cold water to provide "critical period cooling".

Coefficient of performance

The coefficient of performance ("CoP") is a measure of the efficiency of a given heat pump under standard conditions: the change in heat delivered over the electricity consumed. However, the CoP will vary greatly under different conditions: a modern heat pump should achieve a CoP of 4 if starting from a temp of 10°C from the ground and delivering 40°C to underfloor heating. If the same pump starts from a temperature of 25°C from a ThermalBank it will have half as much work to do to achieve a 40°C output temperature, and this will double the CoP achieved.

Aquifer Thermal Energy Storage

Aquifer Thermal Energy Storage ("ATES") is used to store energy in open loops in aquifers and balance the heat demand of buildings on a large scale over the seasons.

Borehole Thermal Energy Storage

Borehole Thermal Energy Storage ("BTES") is used to store energy in closed loops in aquifers and balance the heat demand of buildings on a large scale over the seasons.

Solar Road based Ground-Coupled Energy Storage System

This term has also been used to describe Interseasonal Heat Transfer.

Free Cooling

Free Cooling is used to mean "heat dumping" from a building to an external sink purely by means of circulating water to transport heat out of the building. This can also be called direct coupled cooling. "Critical period cooling" is the use of free cooling to cover brief times of high need for cooling - at a much cheaper price than full air conditioning.

Hollowcore Concrete

TermoDeck’s system of hollowcore concrete slabs, first used in the UK in the Elizabeth Fry Building at the University of East Anglia, allows ventilation to pass through the supporting structure of a building. This, in conjunction with a high standard of insulation, exploits the thermal mass of the structure to absorb heat and retain heat in winter. In summer the ceiling units can be cooled overnight by circulating air through them. This eliminates the need for mechanical cooling systems during the day.

Hollowcore concrete construction works well with Interseasonal Heat Transfer, as demonstrated at Howe Dell School, Hatfield.

Earth Tubes

Earth Tubes are a means of stabalizing the temperature of ventilation air drawn into a building through tubes in the ground to cool incoming air in summer and heat incoming air in winter.

A Ground Air Heat Exchanger ("GAHE") can provide controlled ventilation and improve the air quality in buildings by exploiting the energy stored in the ground. At a depth of 2 metres the ground is a constant 8-12°C. By drawing air through an underground network of pipes, a GAHE can help to heat in coming air in winter and cool in coming air in summer.

Geothermal Energy

Geothermal Energy is derived from heat within the earth. In Iceland and some other parts of the world where high temperatures reach close to the earth's surface it is possible to capture and use this heat. However, this term is sometimes also used to refer to ground source energy from shallow depth, although the heat originates from the sun.

Geothermal Aquifer

A Geothermal Aquifer is a source of heat from a hot spring near the surface, as found in the city of Bath.

Hot Rocks

Hot Rocks is a form of Geothermal Energy where very high temperatures can be reached by drilling down to depths of a few kilometres (at large expense and high risk). There are ambitious plans to commercialise this form of energy in Australia to generate electricity.

There are similar dry rock plans to construct a £30 million power station of 5MW in Germany based on drilling down four kilometres to access ground water with a temperature of 130°C. This might also allow the residual heat to be used for a community heating scheme.

Renewable Heat

Renewable Heat is a form of Renewable Energy for buildings involving the re-cycling of heat from natural resources. Alternative names used for Renewable Energy include: Green Energy, Clean Energy, cleantech and Alternative Energy. An alternative name for Renewable Heat is Green Heat.

Renewable Cooling

Renewable Cooling is the provision of cooling to buildings by using re-cycled natural, renewable resources, instead of consuming fossil fuels. The standard solution for providing cooling to buildings is to use chillers and air conditioning which uses a very large amount of electricity: this is expensive and (if the electricity comes from a power station which is powered by gas, oil or coal) will cause the release of large quantities of CO2 into the atmosphere.

There is a better way to achieve cooling in buildings. This is an exciting by-product of Interseasonal Heat Transfer™. Having installed IHT™ in a new building to provide Renewable Heat in winter all the mechanism is in place for the IHT system to work in reverse and provide Renewable Cooling in summer, at a fraction of the cost of using air conditioning and chillers to provide cooling. An alternative name for Renewable Cooling is Green Cooling.

Climate Change

Global warming is being accelerated by the release of greenhouse gases from burning carbon fuels at a faster rate than they are being captured by nature. This may lead to unpredictable Climate Change, or Climate Chaos.

Alternative Energy

Alternative energy is a term used for any energy source that is an alternative to using fossil fuels. Alternative names include Renewable Energy and Green Energy. The primary source of alternative energy is the sun.

The Merton Rule

The Merton Rule states that:“All new non-residential development above a threshold of 1,000 square metres will be expected to incorporate renewable energy production equipment to provide at least 10% of predicted energy requirements.”

The Merton Rule is named after Merton Council which adopted the first prescriptive planning policy that required new commercial buildings over 1,000 square metres to generate at least 10% of their energy using on site renewable energy. In 2008, the Government's Planning Policy Statement requires all UK local planning authorities to adopt a "Merton rule" policy.

BREEAM

BREEAM is the Building Research Establishment Environmental Assessment Method. A method for assessing the environmental sustainability of a building against set criteria to provide a graded rating from "Pass" up to "Outstanding".

Cleantech

Clean Technology or "Cleantech" is a relatively new term used to describe companies that use innovative technology to create products and services that compete favourably on price and performance, while reducing mankind’s impact on the environment.

IPCC

The Intergovernmental Panel on Climate Change was set up in 1988 to advise on the impact of future temperature rises caused by greenhouse gas emissions. The IPCC 2007 projections range from a rise in global average temperature of between 1.8°C and 4°C by 2100.

Green Heat | Green Cooling | Green Energy Options

See also: Banking on IHT