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New Energy World™
New Energy World™ embraces the whole energy industry as it connects and converges to address the decarbonisation challenge. It covers progress being made across the industry, from the dynamics under way to reduce emissions in oil and gas, through improvements to the efficiency of energy conversion and use, to cutting-edge initiatives in renewable and low-carbon technologies.
Tapping rivers for their heat
11/6/2025
8 min read
Feature
Dams are not the only way to harness the natural power of rivers. Communities and large users, including the University of East London, which is based in the docklands, are tapping into another aspect of water: its heat, to provide indoor warmth to nearby buildings over the winter months. The heat-pump-based systems are more efficient than air-source versions, and scalable too, finds New Energy World Senior Editor Will Dalrymple.
With average annual temperatures of about 12°C, the Thames may not feel warm to the human bather. But for a water source heat pump, it’s all relative. The University of East London (UEL) has contracted Siemens to design and install a water source heat pump to tap into its heat (see Fig 1). With a capacity of 800 kWth, it is said to be the largest fitted at any university. Once installed in a new energy centre, it will replace the buildings’ existing gas boilers and power heating and hot water for UEL’s Docklands Campus Library and Royal Docks Centre for Sustainability buildings (alongside existing air conditioning and a new supplementary heating system).
The heat pump will extract low grade heat (but not water) from the Royal Albert Dock next to the campus. Its refrigeration cycle works the same as any other type of heat pump, whether ground-source or air-source. It’s a cycle that consists of four main stages. In the evaporation stage, the liquid refrigerant contained within the pipes absorbs heat from the water, which causes the refrigerant to evaporate into a gas. From there, the gaseous refrigerant enters the compressor which increases both pressure and temperature of the gas. This creates a high-pressure, high-temperature gas that flows into the condenser. Here, it releases its heat to the building’s heat system. As it releases heat, the refrigerant condenses back into a liquid. The liquid is still under high pressure. Finally, the high-pressure liquid passes through an expansion valve, which reduces the pressure dramatically. The remaining liquid refrigerant is now cold and low pressure. The cycle then begins again at the evaporator.
Submerged in the dock, the closed-loop system will use a set of interconnected pipes, anchored to the bottom of the dock-bed, to capture the heat. An out- and return-pipe will connect directly to the energy centre via a series of sub-surface channels. The system is expected to reduce annual CO2 emissions by 258 tonnes, while only raising the temperature of the water in the dock by a fraction of a degree.