Gas cooling benefits in medical and recreational facilities
Gas cooling systems can help hospitals and recreational facilities reduce their energy costs by providing reliable cooling in facilities where year-round cooling is needed.
A combined cooling heat and power (CCHP) system integrated with gas turbine, heat recovery steam generator and steam chiller can provide heating, cooling and power to the medical center, realizing the energy independence and lower carbon emissions than grid power. While some facilities switch from heating to cooling depending on the time of year, other facilities need to provide constant cool air to meet their facility’s needs.
Consider the example of Baystate Medical Center in Springfield, Mass., which is the biggest hospital in the Baystate Health system. In another case, a mechanical CHP system that used natural gas rather than electricity was able to provide 24/7 cooling to a newly-developed ice rink facility in suburban Boston.
Installing a CCHP at a hospital
Baystate Health initiated a $27 million CCHP plant that provides non-grid energy sources to critical facilities in the event of power loss during a disaster. The CCHP plant is part of the Housing & Urban Development (HUD) National Disaster Resilience Competition.
Baystate Health is a nonprofit, integrated health care system headquartered in Springfield, Mass., serving more than 800,000 people. The system has four hospitals, more than 80 medical practices and 25 reference laboratories.
The trigeneration power plant is located at the largest level I trauma center in western Massachusetts. The plant includes a 4.6-megawatt (MW) gas turbine to produce 80% of its own power, bringing much needed relief to the stressed energy grid. The steam, the byproduct of the combustion associated with the spinning natural gas engine, is also used for sterilization, to heat the hospital and drive a BROAD two-stage steam absorption chiller for summer cooling.
A combined cooling heat and power (CCHP) system was installed at the Baystate Medical Center in Springfield, Mass. Courtesy: Baystate Medical Center/BROAD USA
The CCHP system produces 80% of the electricity and 98% of the steam utilized at Baystate. The system can operate in island mode for 30 days uninterrupted in the event of a utility crisis.
The BROAD absorption chiller uses waste heat from the trigeneration plant, increasing energy efficiency and saving more than 3,000 MWh/year electricity for cooling. In all, the CCHP system reduces annual utility costs at the hospital by almost $1.5 million.
Features include programmable logic controller (PLC) with 24/7 monitoring, no maintenance pumps, unloading down to 5% and proportional-integral-derivative (PID) control with diagnostics to make any required fixes as minimal as possible for the operator.
The high and constant 24/7 demand of electric power, heating and cooling allows CCHP system to reduce energy costs, increase energy efficiency and reliability, and improve environmental performance.
The BROAD absorption chiller uses waste heat from the trigeneration plant, increasing energy efficiency while providing a unit that is designed to improve operator use. Courtesy: BROAD USA
Mechanical CHP benefits for ice rink, cooling facilities
Maintaining championship quality ice surfaces requires precise cooling and dehumidification control, which results in high energy needs. When the Skating Club of Boston relocated to a new facility in Brighton, Mass., energy efficiency was a key focus for the new facility. Tecogen provided five mechanical CHP systems for the facility.
“We have five chillers there for three sheets of ice. There’s one chiller per sheet of ice,” said Stephen Lafaille, VP of business development at Tecogen Inc. “Then there’s an N+1 chiller, kind of like a redundant chiller. The fifth chiller does air conditioning or ice making. It’s called a swing unit. Sometimes its conditioning the air above the three ice surfaces. You want the air above the ice really the right temperature and relative humidity because otherwise your boards are gonna get foggy and you could have water dripping. So you need to condition the air for the right event. Especially if you have a lot of people.”
Tecogen installed a mechanical CHP that uses natural gas rather than electricity to provide constant cooling for the Skating Club of Boston’s new facility in Brighton, Mass. Courtesy: Tecogen
The mechanical CHP system used for the facility operate on natural gas rather than an electric motor. Lafaille said the project was an ideal one because most of their CHP installations are retrofits. In this case, they got a new facility, which provided them an ideal installation because they had free rein to work with the installer and place the chillers where they wanted for the best possible effect.
“We could design it the right way from the get-go. It was the most optimized rink we’ve done,” Lafaille said. “Every place that is using heat in this building is getting it.”
The units chosen for the facility were designed to not only maintain ice conditions as well as air-conditioning the space above the ice, but they were designed to grab free waste heat from the chiller and use it for ice resurfacing, domestic hot water, space heating, ice pit melting and regenerate their desiccant dehumidification system.
Art Sutherland, president and CEO of Accent Refrigeration Systems, said, “Ice rinks by their nature consume a tremendous amount of energy so we always try to do everything we can to reduce the operating costs. It’s the operating costs over the lifetime of the facility that costs a lot more than the first costs of the equipment.”
Lafaille said mechanical CHP can benefit facilities where cooling is needed all year long. He mentioned other industries that benefit from this include manufacturing facilities, food and beverage, hospitals and some laboratories. Any place where cooling & heating are needed simultaneously is where mechanical CHPhas the best economics..
“If you have a building that needs a lot of cooling, why not do it with natural gas? It’s more efficient from a technical standpoint.” Lafaille said.
The return on investment (ROI) for a mechanical CHP is also stronger in a facility where it will continuously run, he said. The payback could be as little as two years.
Ice rinks, Lafaille admitted, are a bit niche in that respect, but it does have one advantage: It’s designed to be open to the public and it gives people first-hand exposure in a setting designed to entertain people whether it’s an open-skate session or a hockey match.
“It certainly helped us demonstrate that our technology can really be reliable and not have a giant pool of water out there. “
That’s a message they’re trying to expound upon, particularly in light of the Inflation Reduction Act, which was passed in August and has tax benefits for the CHP market as a whole. Mechanical CHP might not be as well known, but Lafaille said the door is widening and it’s becoming more possible.
“We’ve been creating awareness that these types of systems exist,” he said. “I think a lot of people know about traditional cogeneration or CHP. If they understand their benefits, they understand there’s a cost, which might be a deterrent. We’re trying to show people there’s another way to solving this problem. You get all the same benefits, but you actually can do it for a much lower cost, making it much more likely for an owner to make the investment.”
– This article appeared in the GasTechnology supplement.
BROAD USA
Baystate Health
Tecogen
Skating Club of Boston
www.scboston.com
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