Heating and Cooling System at National Maritime Museum for Renewable Energy

A £35 million refurbishment and extension at the National Maritime Museum, Greenwich. The project is to double the usable volume and create a range of new facilities in the newly built element alongside it.

To design supply and install an underfloor heating system capable of heating & cooling, utilising a renewable water to water heat source capable of summer time cooling.

We were approached by Mott McDonald Fulcrum (formally Fulcrum Consulting, who we have worked successfully in the past), to design an Underfloor Heating system with cooling capability.

The building was the Sammy Ofer Wing – an 1100m² new building at the National Maritime Museum, Greenwich. Mitie Engineering Service (South East) were the M&E contractors for the project.

The heat source utilised an ATES system (Aquifer Thermo Energy Store), traditionally a Dutch method of storing all the energy required to heat and cool a building deep underground.

The technology uses two boreholes drilled into an aquifer. During the summer, groundwater is extracted via one borehole to provide cooling while unwanted heat is pumped into the aquifer via the second borehole. In the winter months the system is reversed, extracting warmer water to provide heating. By doing this the aquifer is maintained in equilibrium not extracting too much heat nor putting too much back. The resource is then available for use again – totally renewable.

Our underfloor heating system was designed to achieve 60w/m2 of heating and 40w/m2 in summer time cooling mode. We provided condensating and dew point sensors which are a must when using underfloor cooling to avoid condensation build up on floors which could make the floor surface extremely slippery and potential ruin the floor finish.
For this project we used our RUW-K Manifolds complete with Plate Heat Exchangers. We had to use these manifold types instead of a standard LT-S Low Temperature Manifolds because the heating and cooling circuits could not be mixed. The Plate Heat Exchange enabled us to have the correct Flow temperature going to our underfloor pipes without using the Flow water direct. In total we installed 10 Manifolds and a total of 6.8km of 20mm pipe. Our pipe work was fixed to 150mm Celotex Insulation with a 65mm Screed covering the floor area.

The biggest problem we had to overcome was something completely out of our control – the weather! We started installation during the winter of 2010/11 and very quickly the freezing temperatures and heavy snow slowed things up.
Despite the initial delays, we were able to complete on time, ready for the screeders. Once phase2 of the project was complete we were able to return to site and commission the heating/cooling system.

We have completed many underfloor heating projects utilising the cooling capability of a renewable energy system whether it be an Air Source or Ground Source Heat Pump, so were able to advise on parameters and functionality of the cooling system.