ENERGY : Project to Store Heat From Sun Underground : System uses retained warmth year-round. It could revive interest in solar technology.


On a recent rainy day, J. Edward Sunderland stood next to a weedy field here, pointing to the site of a project he hopes will help the nation in its quest for energy independence.

If all goes well, the drab-looking field, on the campus of the University of Massachusetts at Amherst, will one day contain an array of solar collectors capable of supplying heat and hot water year-round to a future 12,000-seat sports arena, along with an existing gymnasium building.

The project, under the direction of Sunderland, a professor of mechanical engineering at the university, would mark the first time in the United States that a facility the size of the arena, which is now under construction, was heated almost entirely by solar energy.

To accomplish the task, Sunderland and his colleagues are making use of a technology that has been used in several European countries, notably Sweden, but has yet to be tried here.


The technology involves storing energy drawn from the sun in the warmer months, underground, to supply heat and hot water all year.

Sunderland said he hoped the $3.7-million project would demonstrate the potential value of the technology.

“This is a strategy that is extremely important for the country,” he said, noting that it offered a practical way to use solar energy while reducing pollution and dependence on imported oil.

Sunderland said that the solar heating industry in this country has foundered until now because it focused on sales of collectors for individual homes.

Such small-scale systems are not economical, he said, because they lack the capacity to store heat from the collectors all winter. The loss of federal solar tax credits and a decline in fuel prices in the 1980s made them even less economical.

But, due to economies of scale, systems built on the University of Massachusetts model are economical, Sunderland said.

Universities, shopping malls, industrial parks, apartment buildings and even homes linked to a central heating source are all examples of facilities that could be heated efficiently by storing solar energy, he said.

The project here involves the placement of solar collectors in the approximately seven-acre field. An anti-freeze fluid within the collectors, heated by the sun, will be pumped through pipes into clay beneath the collectors. The clay will retain heat from the pipes throughout the year.


When heat or hot water is needed, fluid will be pumped through the pipes in the clay pit. After being warmed by the clay, it will continue in underground pipes to the sports facilities, one third of a mile away.

Sunderland said that, because the solar system will not be ready when the arena is opened in 1993, the facility will initially be heated by the campus steam plant, as the gym currently is. But, once the solar system is in place, it will supply at least 85% of the 5,000-megawatt annual heat load of both buildings.

Sunderland said that, within eight years, the project’s costs, plus interest, will have been paid through savings in fuel. Those savings are projected to exceed $5 million after 20 years.

Dwayne S. Breger, senior research associate for the project, said that, with environmental benefits included, “the economics look very good.”


The project is generating interest among those in the solar energy field.

“It’s the first in a genre that could become very important in this country in the next century as we try to shift away from fossil fuels,” said Charles A. Bankston, a Washington solar energy consultant and former U.S. representative to the International Energy Agency.

He said the project could spark interest not only in solar energy but in the potential for storing other energy, such as heat that otherwise would be lost in power plant generation.

Scott Sklar, executive director of the Washington-based Solar Energy Industries Assn., said a project showing that solar energy can be stored over a period of months “will have a profound impact on the public’s attitudes of whether solar energy is realistic or not.”


So far, the university has received $650,000 in funding through the federal Department of Energy to design the project. An additional $3 million is needed to build it.

But Sunderland said he is optimistic about obtaining the funds before work begins in about two years.