The Intelligent Way to Provide Hot Water
The IntelliStation represents a new way to efficiently and safely deliver water to occupants of commercial and industrial facilities.
The residents of The Ackerly at Timberland have all the comforts of home at the sort of home that’s becoming more popular as aging Americans account for an ever growing demographic. The $32 million, six-story, 147-unit community featuring senior independent living, assisted living and memory care apartments opened in the summer of 2016 near Portland, Oregon.
Amenities in the 162,000-squre-foot facility include two restaurants and a pub, along with a fitness and wellness center, activities room, salon, library, theater and tech center.
Outside, residents can take advantage of bocce ball courts, walking trails, a gardening area, a meditation area with a fountain, additional dining areas and an outdoor fireplace.
An important amenity
But there’s another amenity the facility provides that residents rarely give much thought to — a constant supply of safe hot water delivered whenever and wherever residents need it.
Quietly doing its work in one of building’s mechanical rooms is an IntelliStation, a digital water mixing and recirculation system developed by Powers, a Watts brand.
“It’s a safer and more energy-efficient way to deliver hot water within a much tighter temperature range,” says Bruce Fathers, product director for Powers.
A smart controller with 3.5-inch full-color touchscreen interface displays nearly 200 combinations of critical data, including mixed outlet temperature and mixed and return flow, as well as energy consumption.
“Regarding installation,” Fathers adds, “we like to say, ‘Plug and play and walk away.’”
Contractors only have to deal with five water connections upon installation: hot and cold water supply; mixed outlet; return; and boiler. Then only power is needed. At that point, the IntelliStation automatically controls outlet temperature without too much more effort on the contractor’s part. The IntelliStation is commissioned in minutes.
“The engineer knows it’s done right because we assemble it, we test it, we calibrate it and we ship it. It’s all done to their specification,” Fathers adds.
Digital mixing provides an automated approach to what has largely been a mechanical process for the past century, full of extra effort, needed to ensure that systems are balanced properly.
“I knew that the IntelliStation’s digital approach would be a more precise way of providing The Ackerly with hot water,” says Clifford M. Hood, an engineer with Hood-McNees Inc., Portland, Oregon, who specified the system. “There’s always a lot of guesswork in determining how much hot water a building this size needs, and some of our sizing information is 40 years old.”
Regardless of the challenge, residents’ expectations must be met. “There’s hell to pay if there’s not enough hot water,” Hood says. “When there's not, I get the contractors and owners and everyone else mad at me. So I don’t dare cut corners on hot water.”
The IntelliStation incorporates a complete programmable system to monitor data on temperature, flow and pressure, which is obtained from sensors on or near the hot and cold water inlets, mixed outlet and mixed water return. High-speed electronic actuation driven by an onboard controller modulates a simple three-way ball valve that allows the temperature set point to be continuously maintained.
‘The IntelliStation self-balances itself 10 times a second, 365 days a year,” says Dan Checri, business development manager — tempering, west region, for Powers. “No Thanksgiving. No Christmas. No vacation.”
This digital approach even exceeds code requirements of the ASSE 1017-2009 Standard, which governs performance for large hot water distribution valves.
For larger valves with flow rates of more than 40 gallons per minute, the standard requires that they hold to plus or minus 7 F. In other words, if the set point is 140 F, the valve must keep water temperature to within 133 F to 147 F, a 14-degree range.
Digital mixing, however, can deliver much more precise control and hold the set point to within plus or minus 2 F.
The digital approach represents a considerable change in how engineers and contractors control and deliver water to large buildings. Traditionally, thermostatic mixing valves have been the predominant method, and they still account for about 90 percent of the digital mixing used in the commercial/industrial building market.
Some of the first high-capacity master mixing valves were developed in 1919. Powers was the first company to use paraffin actuation for large TMVs; other TMVs rely on ether or bi-metal.
“The reason we developed the IntelliStation was to improve safety and efficiency and to digitize what up to this point has been, by and large, a mechanical process,” Fathers explains.
TMVs and digital
TMVs are fairly easy to comprehend. The temperature within a mixing valve is affected by fluctuation in the inlet water temperature and pressure, as well as demand on the system. Heat is transferred through the walls of the sensor and passed to the media. The transfer expands the media and changes the ratio of hot to cold water. As the water gets warmer, a piston moves up, closing off the hot water and opening the cold to maintain the set point temperature.
For TMVs to work correctly, however, the system must be properly designed and balanced. They work most effectively under ideal conditions with equal inlet supply pressures and when there is no more than a 20 percent pressure differential across the inlets.
“The challenges that TMVs have in terms of controlling water temperature can be as simple as seasonal water temperature variations or the mechanical failure of different devices in the larger water distribution system,” says Matthew Fratantonio, lead program manager for Powers during a presentation at the 2016 ASPE Convention & Expo in Phoenix.
Fratantonio also cited improper valve selection as another concern.
“Engineers are specifying larger valves than they need as insurance against having insufficient capacity,” he explains. “But at lower flows, these mechanical valves experience a lot of trouble maintaining temperature control.”
Plumbing Engineer recently teamed up with Powers and Watts for a webinar on digital mixing technology. In his presentation, Todd McCurdy, business development manager — tempering, east region, Powers, pointed out some difficulties with TMVs:
- They are subject to temperature creep in low- or no-demand periods, typically overnight.
- They require checks and regular maintenance to avoid performance problems.
- TMVs tend to be more susceptible to problems caused by water chemistry because the actuator operates in the water.
- They cannot communicate with a building automation system (BAS).
TMVs have high approach temperatures — as high as 25 F. As a result, the hot water supply must be at least 25 F higher than the desired mixed outlet temperature, which is not very efficient.
If TMVs can be considered the rotary dial phones of water systems, then digital mixing systems can be viewed as iPhones. The advancement in technology is considerable.
The IntelliStation is easily configurable in the field and does not require the use of proprietary software or laptop computers. Integrated in a BAS using BACnet and Modbus protocols (native to the controller), the lead-free IntelliStation supports integrated building management. Depending on the configuration, the building’s hot water can be monitored and controlled remotely.
“We’ve done a ton of mechanical valves,” says Ross Tapani, president, Tapani Plumbing, Battle Ground, Washington. “They’re tricky beasts, but we’ve worked the kinks out. We know how to pipe them and make them work.”
The Ackerly’s system is the first IntelliStation the mechanical contractor has installed.
“We’d gotten to the point where we were comfortable with TMVs,” says Alex Massie, foreman, Tapani Plumbing. “But the IntelliStation seemed to take a lot of the guesswork out it.”
It certainly took the guesswork out of the commissioning process.
Eugene Likhonin, Tapani’s finish foreman, says he could easily spend a full eight-hour day adjusting and balancing a mechanical system to get the settings just right.
“I could spend a lot of time turning a valve a 1/16 of inch, thinking I’d adjusted it just right — and it would go cold. I’m always fighting against bigger and smaller mixing valves — not to mention dealing with the differences between a new building that is half-occupied and one fully occupied or handling situations where the heat is on or those where it isn’t. With the IntelliStation, I switched it on and basically walked away.”