Emily Myers in Green Ideas
The London Towne House is getting an energy boost thanks to high-efficiency motors and “smart” temperature tools — as well as a boost to its bottom line. The new technology installed at the 16-story, 217-unit co-op in Chelsea has modernized its two-pipe heating and cooling system, making it much more variable and efficient. “Until this year, systems in the building ran at 100% all of the time,” says Richard Cariello, a resident on the building’s energy committee. Now, heating and cooling can be adjusted depending on factors like external temperature and demand within the building.
With the help of the free city-run program NYC Accelerator, the co-op’s energy team figured out this fine-tuning could be done by installing high-efficiency motors for the building’s 26 exhaust fans, variable frequency drives (VFDs) for the pumps, and real time energy management (RTEM) for the entire system.
Motors in a two-pipe hydronic system are responsible for driving pumps to circulate water for heating and cooling. High-efficiency motors feature variable speed control. “If you scale back the speed of a motor it saves energy when it doesn’t have to run at full speed all the time,” says Corey Harris, a technical engineer with Parity, the company that installed the VFDs.
VFDs allow for the frequency of equipment to be adjusted. For example, the building’s cooling-tower fan spins to produce adequate condenser water for the chiller in summer and the new VFD allows the fan to be operated at a lower frequency. “Instead of running it at 60 hertz to reach the set point for the condenser water, it’s possible to run it at half speed for longer and generate savings,” Harris explains.
With the support of the building’s management team at Halstead, the board signed a five-year contract with Parity to monitor energy use and make real time adjustments. This means motor speed and water temperature are constantly being tweaked based on data retrieved from the building. “We are looking at the energy load with respect to the weather conditions and things going on in the building to make an analysis of when you can reduce the load,” Harris says. So instead of sending 150-degree water to circulate at all times, the temperature can be lowered when demand slows.
The equipment was installed for around $76,000 and generates annual savings of $40,000 on energy costs. Spring and fall are when the building reaps the most savings. “After the changeover to heating, Parity can ratchet down the heat when it’s still relatively warm, and after the switch over to cooling, Parity can do the same when it’s still relatively cool,” Cariello says. Automating the process helps alleviate the workload for building staff.
As for the return on investment, handsome incentives made adopting the technology a no-brainer, according to Cariello. The VFD and RTEM installation was priced at $123,900, but a $66,000 incentive from Con Edison slashed the cost to $57,000. The dual installation will save the co-op about $32,000 a year; factoring Parity’s annual service fee, the upgrade will pay for itself within three years.
In addition, a $24,000 Con Edison incentive trimmed the price tag for the new motor equipment, which was installed by DVM Industries, from $43,000 to $19,000. Annual savings from the high-efficiency motors are estimated at $10,000 per year. “So we are getting a payback in the second year,” Cariello says.
Thanks to the tech upgrades, which were financed from the co-op’s reserve fund, the 229,000-square-foot building is currently projected to meet Local Law 97 emission requirements until 2035. Even so, the retrofits are just the start of London Towne House’s energy journey. With the help of incentives from NYSERDA, the board received a FlexTech energy report to inform their future energy-efficiency decision-making. “It identified the age of our HVAC equipment and potential routes to replace it and meet our future Local Law 97 requirements,” Cariello says.
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