Waterways can heat a million homes, says UK government

The country’s energy department is banking on a Scandinavian-style technology to heat homes

By Deepanwita Gita Niyogi
Published: Thursday 26 March 2015


Taking a step towards clean energy, a recent UK government press release said more than a million homes and business establishments across England could be heated by using water from nearby rivers, canals, estuaries and the sea.

According to the release, UK’s energy department is banking on the Scandinavian-style green technology, known as water source heat pump to achieve this. Energy secretary Ed Davey is leading a campaign to promote the use of heat pumps—carbon-free devices that extract thermal energy from waterways to heat radiators and showers in buildings.

“We need to make the most of the vast amount of clean, renewable heat that lies unused in our rivers, lakes and seas,” Davey said.

“Doing this will help contribute to an energy mix that maximises clean, reliable home-grown resources rather than relying on foreign fossil fuels.”

Davey said more than 4,041 waterways have been identified to heat homes. Taken together, these can provide over six gigawatts of low-carbon heat to communities.

The government thinks it is feasible to do this as more than a million homes in the country lie close to water sources. The hot spots include buildings around the Ouse river in Selby, the Trent river in Nottingham and the Thames in London.

How the system works

The technology relies on a heat exchanger, which uses a system similar to refrigeration, to amplify warmth from pipes laid in the water. Water source heat pumps take heat from the water and then feed it into local heat networks or individual buildings.

The National Trust’s historic Plas Newydd house in Anglesey is running on this technology where it sucks heat from sea.

The heat pump system works best in well-insulated buildings as there is a large energy cost in warming the water to the level used in central heating radiators.
However, in the case of Plas Newydd it is ideal because the trust does not want the house to get too hot.

Here, the pipes have been laid into the Menai Straits, the narrow stretch of water which separates the island of Anglesey from Wales. The pipes are filled with a refrigerant heat transport chemical. The fluid extracts heat from the sea and releases it into the heat pump.

The fluid is then compressed to increase the temperature further to heat the property. The pressure of the fluid is then lowered through an expansion valve and the process starts all over again.

A move towards clean energy
Installing a water source heat pump reduces the need for dirty gas-fired domestic heating as it allows an average household to reduce its carbon footprint by as much as 50 per cent.

The energy produced is both clean and renewable and households can knock as much as 20 per cent off their heating bills, Davey added.

History of water pumps
Water source pumps date back to the 19th century and are popular in Scandinavia where they are mainly used to heat homes. However, they are far less common in the UK and have been rarely used for large-scale community projects. The government hopes they will become popular.

In a recent move, the developer owning Battersea Power Station, a decommissioned coal-fired power station located on the south bank of the River Thames which is being redeveloped into residential apartments, announced it would look into installing a water source heat pump.

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