A sustainable revolution in the making

ICAX Limited has recently completed an installation of its innovative sustainable technology at Garth Prison in Lancashire. This is potentially the first step for a new generation of on-site renewable prison houseblocks, heralding a significant advance in public sector sustainable thinking.

ICAX were approached by Mike Phillips of Home Office Custodial Property who had spotted a potential use for IHT technology in the sector. Following a careful feasibility study, it was decided to test it out in a new development at Garth which was completed in September 2007. This was overseen by Allan Kelly of Interserve Engineering, with Mechanical and Electrical consultancy from the Leeds office of Hoare Lea.

ICAX technology provides a sustainable, on-site renewable energy technology for a wide range of building types. Prison houseblocks are particularly suitable, since their highly predictable heating loads and high thermal mass make them ideal for this revolutionary new technology.

Interseasonal Heat Transfer (IHT) is a patented technology that is complementary to both Solar and Ground Source Heat Pumps. IHT provides a method for storing heat for long periods – between seasons. This means excess heat generated by solar panels, chillers, or asphalt solar collectors in summer can be deposited in thermal storage until it is needed in winter: sustainable energy solutions.


A Thermal Bank is created by installing pipework in the ground beneath the building when the foundations are created. During summer excess heat is transferred from the solar system and deposited in the Thermal Bank. During winter heat is withdrawn from the ThermalBank and transferred to the building via a Ground Source Heat Pump. For a prison houseblock, the exercise yard makes an ideal collector surface. A pipe array is embedded in the surface, just below the asphalt layer, and the heat collected in the summer months can then be stored in the ground beneath the houseblock building.

Ground Source Heat Pumps (GSHP) have a great potential for reducing carbon emissions, but can suffer from poor performance when the temperature of the ground becomes too low. An IHT system actively deposits heat energy into the Thermal Bank in summer in advance of the heating season thus improving the performance of the GSHP which withdraws from the warm Heat Bank in winter.

Invisible Heating Systems

Unlike most other renewables technologies IHT systems are invisible and do not, therefore, require planning consent.

IHT is also vandal proof, which is significant in the prison context.

At Garth a 420m2 collector has been installed in the exercise yard. Since the houseblock had already been constructed, the energy collected will be used to pre-heat hot water to meet the enormous demand for cooking and washing in an adjacent facilities building. However, now the system has proven to be easily assimilated into the building process for prisons, ICAX Limited are looking forward to developing complete building solutions for this sector.

Mark Hewitt, Director of ICAX, says “Prisons are built to a tight formula for best value. It was important for ICAX to demonstrate to a major public sector client that IHT technology could be incorporated into this way of construction, without disruption. We are pleased that we were able to show this at Garth, and we are very much looking forward to moving to the next level, which is to provide heating to houseblock units. That would be a great achievement for public sector construction sustainability.”

See also: Banking on IHT

See Ground Source Heating       See Ground Source Cooling      See Ground Source Energy