Sunday, December 26, 1999

Heating with waste, wasting less heat

Published in the Antarctic Sun

Facilities engineers are building two kinds of energy-saving networks around McMurdo Station. One network, of pipes, permits them to heat buildings at little cost. The other network, of wires, lets them centralize monitoring and control of heating systems in buildings around town.

Until recently, the power plant’s engines were cooled by giant radiators sitting behind the plant. The energy, called “waste heat,” escaped into the air. Last week, that changed.

Rather than transferring excess energy to the outside atmosphere, waste heat is now warming three McMurdo buildings. Facilities engineer Jim McAdam puts it another way: “We’ll do all the cooling of the engines with the town,” he said.

This is not the first time waste heat from the power-generation process will have been put to good use around McMurdo. When flash evaporators were used to purify seawater into drinking
water, excess heat from the power plant was part of that process. As well, the water plant has been heated with waste heat since Winfly 1998.

The new system came online in Crary and buildings 155 and 165 on Monday night. Eventually, the project will include the science cargo building, the firehouse, the hospital and the dorms.

“It went real well,” McAdam said of the changeover to waste heat.

It works like this: The water cooling the power plant’s engines will radiate heat to a loop containing a 60-percent glycol, 40-percent water solution. That solution will be pumped to buildings heated with the waste-heat system.

The buildings’ existing heating will remain in place as backup, and will automatically kick in if the primary system has problems. There is also a large boiler at the beginning of the waste-heat
loop that can substitute the engines’ waste-heat supply.

With waste heat as the main heat source for major buildings around town, boiler emissions will drop by 25 percent and over 450,000 gallons of fuel will be saved each year.

“It’s a win-win deal,” McAdam said.

The use of waste heat effectively doubles the efficiency of the engines. At present, only 31 percent of the energy put into the machines as fuel emerges as electricity.

The remaining 69 percent is emitted in exhaust and radiation from the engine itself (39 percent), and the heat removed by internal engine coolant (30 percent). It is the energy removed by internal coolant that will now be used to heat buildings.

The plan is also to replace the existing power plant with newer, more efficient generators. At that point, heat will also be collected from the machines’ exhaust and added to the waste-heat

The layout of McMurdo is ideal for this type of project, McAdam said, because the power is generated close to the community it serves. Thus, it is relatively easy to move the heat around

The added efficiency of the waste-heat project is enhanced by other heating-system work going on around station.

As the engineers install waste-heat equipment in buildings, they are also checking for sources of potential heat loss.

Changes to Crary’s heat flow have cut the building’s heating requirements by half.

“We’re identifying key heat-wasting points,” McAdam said.

Another part of the project, which is also being piloted in Crary, is a remote system by which technicians in the power plant can monitor heating equipment around the station from a computer terminal.

Instead of having to go to each building to check equipment and temperatures, automated sensors throughout the new heating system will make those checks continuously.

One benefit of the new monitoring system will be a better understanding of how heating problems happen.

Rather than solving individual problems called in by building occupants, a technician will be able to look at a whole building at once to see where the real problem is. For example, if a building
is too hot because it’s not venting air properly, a repair can be made to the vent rather than to the heat supply.

The monitoring system also increases the efficiency of the waste-heat supply system. Along with variable-speed pumps, electronic monitoring permits fast response to changes in demands for heat around town.

“You just pump exactly what you need,” McAdam said. “It’s a little bit of new technology down here, but anywhere else it’s not.”

The project is ahead of schedule. Crary was the only building planned to come online this year, but buildings 155 and 165 are also being added now, rather than next year.

“We’ll have the whole project paid for before we finish,” McAdam said. It’s a seven-year plan that will pay for itself in less than three years.

“We can put in as much energy as we need and stop wasting so much of it,” McAdam said. McAdam is very proud of the team working with him on all the changes to the heating system around McMurdo.

“Those guys have put a lot of heart into this,” McAdam said of the workers who spent the winter on the project.

The bottom line, he said, is most important for the entire team. “When I leave we’ll be using less energy than when I arrived.”