What is Road Energy?
A Road Energy System (RES) is a series of pipes and racking that collects the heat generated by the Sun shining on black asphalt.
Typically a RES collects on average 250 kWh/m2/annum.
Racking is bonded to a base course and pipes are clipped into the racking. Asphalt is poured over the racking & pipes.
Glycol is circulated through the pipes using a circulation pump, the operation of which is controlled by a digital controller.
Heated glycol transfers the heat to the ground, usually via boreholes where it is stored until winter.
In winter the process is reversed and the heat is recovered for use in combination with one or more ground source heat pumps to provide heating and domestic hot water to the building.
What are the Benefits of a Road Energy System?
The main purpose of a RES is to provide more ground energy to the GSHP system than would normally be available from a given area of available land.
RES increases the temperature of the ground so providing higher temperatures to a Ground Source Heat Pump (GSHP) System, improving the heat output efficiency to the building.
RES can be the difference that makes a GSHP system practically viable where collector space availability is limited.
Application of RES can mean that a smaller rated heat pump can achieve the same heat output as a larger rated unit without road energy.
The increased temperature of the ground reduces the amount of electrical energy input and substantially reduces CO2 produced when generating heat to a building by a GSHP.
Road energy in winter can be used to defrost icy road services.