Under-road Heating - The Solution To Winter Road Closures?
Over the weekend the BBC had an article about Dutch towns that were proposing to heat their cycle lanes to prevent ice and snow build up and ensure that they were safe to use throughout the winter. We get numerous requests each winter for details of the under-road heating system that we can offer here as many people see this as a possible panacea to the problems of snow-blocked roads, paths, driveways or even runways!
The first thing to be aware of is that there are a number of different sub-road heating systems and each is suitable for different situations:
In some countries in Scandinavia, and also in Iceland, heated water pipes run beneath some roads and pavements ensuring they remain ice-free. In Scandinavia the heated water is piped around towns as part of the District Heating infrastructure where hot water is produced centrally and piped out to houses. In Iceland the hot water is produced geothermally so this is a carbon-neutral way of heating a road. By their very nature both of these types of system can only operate where the infrastructure already exists to supply the hot water however where they are installed they can be used to protect large areas.
An alternative method of heating roads is to use a system that re-cycles solar energy by collecting the heat in the summer when the tarmac heats up and then stores it either in a earth or concrete bank, or within a borehole. Water is heated during the summer months by pumping it around in pipes beneath the road surface and it is then pumped into the heat store. Once cold temperatures hit the heat can be retrieved from the thermal store using a ground source heat pump and this water can then be pumped back beneath the road to warm it up. These types of system are more energy efficient than simply using a gas boiler to heat the water however they infrastructure cost of installing them can be high and very disruptive. They are most suited to large areas where the roads need to be heated for long periods of time.
Heat Mat's method of heating roads and driveways uses our tried and trusted 7mm cable system which is an electric heating element that is laid beneath the road surface. The heated cables are controlled by an intelligent thermostat which monitors air and ground temperature as well as moisture levels ensuring the system only heats when required. The benefits of Heat Mat's sub-road heating include its quick reaction time and full automation and the very low cost for installed systems compared to alternatives. For larger projects the cost of the heating system is as low as £25/psm and the installation is straightforward and quick.
Once installed there is absolutely no maintenance required for the heating cables and the system will automatically switch on and off as it is needed. Although there must be a power supply to the site to enable the system to operate in cases where this supply is restricted it is possible to selectively heat areas (for instance just the tyre tracks on either side of the road) to reduce the power requirements. Although the overall power consumption of the systems is significant for large areas the intelligent control gear ensures the system is only powered up when required and it is surprising on how few days a year significant snow falls which would necessitate the heating of the road.