UN has used East River water to cool its New York headquarters for 70 years
A pump sucks water from the East River for the UN headquarters in New York: An old energy-efficient air-conditioning system could expand as the world seeks cooler places to live.
This refrigeration system has been in operation “from the beginning, integrated into the design” of the headquarters opened in the 1950s, explains chief engineer Michael Martini, as he shows the facilities to AFP.
Modernized during a major renovation between 2008 and 2014, it allows the UN complex to be cooled – with a temperature limit of 24-25 °C – with less energy consumption than a conventional air conditioning system, a growing trend in the face of climate change.
Even in the height of a New York summer, “the river is 75 degrees Fahrenheit, not the 100 degrees Fahrenheit” of the ambient air, notes David Lindsay, who oversees the system. So it takes “less energy” to cool it.
Every minute, up to 26,000 liters of salt water are pumped from the East River (an arm of the sea) through large fiberglass pipes to the cooling plant. In the process, a refrigerant gas is used.
Lindsay explains that there are “two independent circuits” to avoid any contamination of the seawater, which then returns, warmer, to the estuary that borders Manhattan.
The New York headquarters is not the only UN facility that uses water. The Palais des Nations in Geneva is connected to a cooling network that uses Lake Geneva, and the United Nations City in Copenhagen pumps water from the sea, which has “virtually eliminated” the need for electricity for cooling.
The advantage is clear over the 2 billion individual devices installed worldwide.
The number of individual refrigerators is set to soar in the face of increasingly high temperatures, while their electricity consumption has tripled since 1990, according to the International Energy Agency, which is calling for more efficient systems such as central grids, geothermal or hydrothermal energy, such as the one at UN headquarters.
While this method has proven effective, “it is not being implemented enough to solve the problems we face,” Lily Riahi, coordinator of the Cool Coalition, which brings together states, cities and companies, and is supported by UN Environment, told AFP.
In addition to complexes large enough to have their own system, this type of infrastructure requires urban planning involving multiple stakeholders.
“We know it is technically possible and we have several case studies demonstrating its cost-effectiveness,” says Rob Thornton, chairman of the Energy Networks Association, which supports the development of district heating and cooling systems.
“But it takes someone — an agent, an advocate, a city or a supplier — to bring together enough customers to make the risk manageable,” he says.
In Paris, Europe's largest cooling network is now in operation, using the River Seine to cool and heat the city and especially the Louvre Museum.
These networks also help reduce the use and leakage of harmful gases and prevent more heat from being released into cities already sweltering in heatwaves.
Some environmentalists are concerned about the impact of warming waters on aquatic ecosystems. These are “legitimate” concerns, says Lily Riahi.
But they are a much smaller problem than coolant runoff from nuclear power plants and can be avoided by “setting temperature limits” for the water, he says.
The UN Environment expert also recommends installing “inlet filters to prevent aquatic organisms from being sucked in”.
At UN headquarters, sea creatures occasionally slip through the net. And several meters below the surface, the East River reservoir is known among some officials for harboring seafood…
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