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Stanford has developed a unique system for reverse heat generation
Last reviewed: 02.07.2025
Leland Stanford, a private research university in California, employs Nobel laureates who make a discovery almost every day.
One of the best was the latest development by specialists – a heat recovery system, which has already been put into operation and is used for heating and cooling buildings.
The developers used a unique heat recovery system and, by capturing a large percentage of solar energy, the university reduced greenhouse gas emissions and fuel use by almost 70%.
The campus covers over 32 km2 , with over a thousand buildings. The total amount of emissions into the atmosphere is over 150 thousand tons annually.
The new system replaced a natural gas-fired power plant that was commissioned in the late 1980s. The power plant used an underground network of steam pipes to heat and cool buildings. Joe Stagner, Stanford's executive director of energy management, explained that cooling is a process of collecting heat, not delivering cold, as many people mistakenly believe. Steam circulates through pipes and returns to the power plant as hot water, just as the cooled water, after heating the buildings, returns to its starting point. As a result, the power plant simply released excess heat into the atmosphere using a cooling tower, i.e. it was spent irrationally.
As the campus grew, the existing heating and cooling system could no longer cope with the load, and the university was forced to purchase energy, which was expensive.
University engineers noticed that the circulation of chilled water and steam was almost parallel, and then the developers came up with the idea of creating a system for recovering heat using renewable energy sources.
The new system is called SESI. It uses heat that was previously lost to the atmosphere, the system moves hot water from the cooling pipes to a new cycle, so that heat is not wasted. The university replaced steam pipes with hot water pipes, and also converted connection points from steam to hot water.
The town has now significantly reduced its emissions by using renewable energy sources.
Special software was created to control the SESI system. According to the developers, the new heating and cooling system is 70% more efficient than a thermal power plant and allows for a significant reduction in heat loss. SESI was also developed with a 25% capacity reserve, which is capable of covering the costs of the expanding town until 2050. Since there is no longer any loss of steam, the savings in water supplied from the central boiler house with the introduction of the new system are 70%, in terms of the total volume of water used in the town, the savings are about 20%.
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