“As engineers, we can really make a difference.”—Hemant Mehta
New York, NY (PRWEB) July 30, 2012
Four famous healthcare institutions in New York and California are now saving a total of nearly $2.5 million dollars per year on their energy bills with simple--but smart--engineering modifications of their central cooling plant equipment that were implemented with little or no cost.
All of the facilities were experiencing runaway energy costs, and contacted Hemant Mehta, the president of WM Group Engineers in New York City for help. His innovative engineering approach produced results surpassing expectations for each organization. Details follow:
Memorial Sloan-Kettering Cancer Center, New York City— now saving $1 million per year
Problem: World-renowned Memorial Sloan-Kettering had been aggressively expanding its facility—and faced additional costs for cooling and powering the new space. To make things more challenging, mid-Manhattan’s electric power grid was overloaded, and the New York State Energy Research and Development Authority (NYSERDA) had imposed a premium on electrical peak-power costs to reduce load on the grid. Memorial Sloan-Kettering contracted WM Group Engineers for help.
Analysis: Mehta found that the hospital was running four independent chilled-water cooling plants across the campus. His analysis of the system produced a very surprising result.
Solution: Mehta confirmed that by removing more than 30 pumps in the distribution piping system, the operation would be dramatically more efficient and flexible. Because the project would reduce peak electric demand, the hospital applied for and received $640,000 in funding from NYSERDA to perform the work.
Removing the pumps resulted in a 1.1 megawatt reduction in peak electric demand and a $1 million annual savings in the hospital’s annual electric bill. Because the system was so much more efficient, a number of the chillers at each individual plant were no longer needed. The idled chillers have become a stand-by fleet that can be used to meet the needs of further expansion, offsetting millions of dollars in future capital costs.
New York Presbyterian Hospital, New York City—now saving $176,000 a year
Problem: At New York Presbyterian Hospital, heating plant managers noticed temperatures in their boiler chimneys, called stacks, much higher than the normal range of 300–350ºF. Concerned about safety, they called WM Group Engineers for help
Analysis: Mehta discovered that a damper in the stack that should have been closed was left open. The open damper allowed the boiler burner exhaust gases to escape up the stack before being routed to a device called an economizer—a heat exchanger that transfers excess heat from the flue gases to preheat process water going to the boiler.
Solution: The damper was closed—a no-cost procedure—forcing the gases through the economizer. Plant efficiency improved by 3.2% improvement and annual fuel costs fell by $176,000. Said Paul Schwabacher, the hospital’s vice president of facilities, “Not bad for closing a damper.”
Wyeth Bio Tech, Pearl River, NY—now saving $190,000 per year plus staff costs
Problem: At Wyeth Bio Tech, district energy chiller plant energy use and costs were higher than normal, but didn’t know why. They called WM Group Engineers to investigate.
Analysis: Mehta found that the Wyeth plant was running two centrifugal chiller plants. Each was operating well under 70% capacity. Centrifugal chillers are designed to operate at 70% or higher loads. At lower loads, they are much less efficient.
Mehta found that while Wyeth’s two chiller plants were interconnected, the operators were running both plants during low-load conditions because they thought that shutting one down would risk failing to meet the critical cooling needs of the hospital’s data center and a vaccination facility.
Solution: Mehta said, “We trained the operators in the fundamentals of hydraulics and chilled water. Afterwards, they understood that they could shut down one plant during low-load conditions.” Implementing this solution cost nothing—and the facility benefited with annual electric savings of $190,000 plus the staffing cost to run the second plant.
Amgen, Thousand Oaks, CA—now saving $1,109,488 per year
Problem: Abnormally high pressure loads were stressing the primary pumps in the chilled-water air conditioning system. The plant operators couldn’t determine the cause, and contacted WM Group Engineers to help.
Analysis: Mehta found that a disk valve on a dead-end stub intended for a future connection was installed too close to the large main distribution pipe—and was left in an open position (see diagram), partially blocking the flow of chilled water.
Solution: Closing the valve solved the problem. In addition, Mehta interconnected the two main chilled water plants to make a single virtual central chiller water system. Amgen was able to shut down one plant for most of the year, reducing power consumption by one megawatt, and annual electric costs by $1,109,488.
Big improvements in district cooling plant efficiency can often be achieved by thorough engineering analysis and the application of low or no-cost “smart solutions.” Mehta said that "We recommend that facility managers empower their plant operators to read and interpret the data captured in operating logs. Not only will this enhance their understanding of plant operations, but it will also make them proud of their work.” says Mehta. “As engineers, we can really make a difference.”
About Hemant Mehta
President and Principal Hemant R. Mehta, PE, founded WM Group Engineers in 2000, and serves as president and CEO. He is an active member of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the International District Energy Association (IDEA). In 2011 and 2010, the Association of Energy Engineers (AEE) named him the Region I Energy Engineer of the Year,. He may be reached at hmehta(at)wmgroupeng(dot)com.