Geothermal and sheet piling are just two of the trends emerging in the sector, writes Oonagh Reidy

Some major developments are occurring in the piling field of late including geothermal and innovative sheet piling systems as well as new form of ground improvement to facilitate what firms are saying is a marked increase in the demand for these type of systems from within the industry.

 
Geothermal piling is one trend that is certain to be come increasingly popular in the energy efficiency era, where the piling will be multi purpose – heating the house as well as providing a foundation for the building. This piling system uses structural piles to capture geothermal energy from the surrounding ground.

Installing geo thermal piling allows ground heat to be channelled up through the building, meaning zero cost for the occupiers. The most appropriate heating systems to facilitate geo thermal energy are the low temperature systems in floors and ceilings are geothermal energy.

When the sun heats the ground its energy seeps through the piling which is is then absorbed by water contained in a U shaped pipe installed in the pile. The water is warmed to about 4°C higher than normal. The heat from the water is then converted through a heat pump containing a "heat transfer medium" or refrigerant which, through a process of evaporation, compression, condensation and expansion increases the temperature to 550C.

For every unit of electricity the system uses, it provides an average of six units of heating / cooling energy, i.e. the system has an average coefficient of performance (COP) of around six. Such a piling system was recently incorporated recently in a school in the UK, where for every 1kW of energy used to power the pump, 6kW of energy can be used to heat and cool the building. This involved the installation of 190 piles that were of 400mm diameter, installed to a depth of 17m.

The carbon emissions emitted by the building can also be reduced by up to 50%, making this piling method an extremely attractive proposition. In addition to heating buildings, geothermal piling can also cool buildings using a refrigerator unit where the capacity of the ground is inadequate for direct cooling.

Sustainable Energy Ireland gives grants for this type of system under their Greener Homes Scheme (GHS) for homeowners and REHeat programme for industrial, commercial, public and community premises. In May of this year alone, sixteen counties throughout Ireland had installed heat pumps into their homes, although no figures on how many of these incorporated geothermal piling were available. Similar to the SEI, the UK also offers grants to commercial and to install geo thermal heating systems system as part of their low carbon scheme.

This is an edited version of an article from the July/ August edition of Irish Construction Industry Mgazine - Click here to Subscribe