Classic architecture and elegance define the Amway Grand Plaza Hotel. Built in 1913, this 29-story luxury hotel in Grand Rapids, Mich., is truly a work of art. Even its internal infrastructure is beautifully designed. The Amway relies on cooling water towers for its heating, ventilation, and air-conditioning (HVAC) system. Located on the roof of the building, the water towers air-cool water that circulates throughout the building to maintain even temperatures. Although this evaporative method is more energy efficient than a typical air conditioner, the concern is the quality of water, which has a large impact on the efficiency of the system. All water tower systems carry a risk of waterborne and airborne particles, which must be eliminated for the system to work properly. Debris — dust, pollen, seeds, even birds — can all find their way into the water towers. Particles settle inside the tubes, reducing thermal dynamic efficiency of the chillers and reducing the system’s ability to transfer heat, causing the chiller to work harder. It’s a costly energy drain.
“One-sixteenth of an inch of particle debris reduces the efficiency of the cooling system by 10 percent,” notes Mike Boyd, west region sales manager with The Macomb Group Macomb Energy Resource Integration Team (M.E.R.I.T.). “It’s like cholesterol clogging up your arteries; it just builds up.”
Objective: Stop working so hard
The Amway had been replacing water, flushing the system, adding chemicals, and annually disassembling and cleaning the filtration system in order to clean the water. It was like paddling upstream in a leaking raft.
Looking for a more efficient and cost-effective way to keep its HVAC system clean and efficient — without increasing the workload of its maintenance team — building managers at the Amway chose to work with The Macomb Group. Together, they selected the John Deere compact self-cleaning filter. Within one month of the order, the filter had been installed.
During the first summer cooling season, the system paid for itself in water and chemical cost savings. The compact filter system, made from NSF materials, has a minimal physical and water footprint, demands little energy, and minimizes the water required to cool the building.
Water costs were reduced a startling 82 percent from former costs. Wastewater generated by the system was cut in half with the new filter. Chemical costs decreased 33 percent from the pre-filtration expense. Annual average cost savings are more than $45,000 a year for the grand hotel.
Even consumption of electricity, which is used to back-flush the system, was reduced by 4 percent during the first year. Although the number of scorcher days in Grand Rapids, Mich., increased by 20 percent in 2010, electricity consumption was still down 2 percent from pre-John-Deere-filter days.
The screen element of the filter, designed to keep dirt, animals, and debris out of the water, is more effective than other screens because of its innovative suction scanner, a high-efficiency cleaning mechanism. The 16-second back-flush cycle, created with simple physics, uses half the water during the cleaning process than other suction scanner technologies. Water and filter cake are pulled through the automatically adjusting suction scanning nozzles at a velocity of 50 feet per second, operating in a spiral pattern to ensure that the entire screen is cleaned. There is no interruption of service during the cleaning cycle.
Up-front investment recouped many times
“The payback on this filter is really significant,” Boyd says. “If you look at the ongoing cost of maintaining and replacing parts of the previous system and compare it to our John Deere maintenance-free filter, it’s a significant factor. You can’t only look at the initial cost; you have to consider the long-term payback involved.”
The cost is not only financial, as The Macomb Group is well aware. The environmental impact is a crucial element when considering HVAC systems. The Macomb Group MERIT department focuses entirely on ways to make its products more efficient to conserve energy and resources, while simultaneously driving down costs.