It may look like an ordinary playground to the children. But the parents know the truth: this tarmac is an Interseasonal Heat Transfer (IHT) system. And that is just one of the features that make Howe Dell the world's coolest school. Rather than following the usual course of including a token gesture for the environment in building plans, Hertfordshire County Council committed to building a zero-carbon school using all the best technologies together to create a perfect model for what is possible.The building itself functions as part of the curriculum. The students "can see how many kilojoules are pumped out be the wind turbines and how that relates to what a kettle or a toaster uses," says Head teacher Debra Massey, quoted in Building Magazine. The school also gets some electricity from solar panels.
As you would expect, the toilets flush with collected rainwater. Hot water is supplied by solar thermal absorption panels on the sedum covered green roof. Carpet squares installed in classrooms reduce waste when areas of high wear can be individually replaced.Classroom fixtures like desks and counter-tops are made from recycled materials.
The IHT is the most challenging advance demonstrated by the Howe Dell School. Pipes running under the playground collect solar heat and transfer it to soils under the building foundation, where insulation and the natural properties of the soil allow the heat to be stored until it is needed, even months later. Cooling is also provided by an underground transfer system. The IHT is compared to heat pump systems, which tap heat stored naturally deeper in the earth. IHT is more expensive to install but is credited with lower maintenance costs. An added bonus from the IHT: excess heat can be drained off of the water heating system, protecting the system from overheating during school vacations.
The project was costly, and required early planning and coordinated implementation to achieve integration of all the eco-efficient systems. The final price tag: ₤2400 per square meter. But costs were high in some cases because there is little experience in building such aggressively eco-efficient schools. The contractors estimate that lessons learned using a ₤250,000 grant to install and monitor the Interseasonal Heat Transfer System will allow them to quote a similar system for ₤75,000 the next time around. You have to start somewhere if you want to achieve green schools by 2020.