The smart way to provide hot water
by Steve Smith
Preliminary Note: This article is the translation of the original published in the January 2017 issue of Plumbing Engineer.
The IntelliStation system is a new, efficient and safe way to provide water to occupants of commercial and industrial establishments.
The $ 32-million, six-storey Ackerly Community Facility in Timberland, home to 147 units, including self-help apartments, requiring services and also loss of memory care, is located near Portland. , Oregon.
The residents of the Ackerly in Timberland have all the comforts of home, but in a sort of “house” increasingly in demand as older Americans represent a growing part of the population. The six-storey, $ 32-million community-owned unit of 147 units, consisting of self-help apartments, requiring services and also loss of memory care, opened during Summer 2016 near Portland, Oregon.
Amenities at the 162,000-square-foot facility include two restaurants and a pub, as well as a fitness and wellness center, an activity room, a lounge, and a library. a theater and a technical center.
Outside, residents can enjoy petanque courts, walking trails, a gardening area, a meditation area with fountain, additional dining areas and an outdoor fireplace.
A convenience of importance
But there is another facility in the facility that residents rarely pay attention to – a safe and permanent hot water supply when and where they need it.
In one of the building’s mechanical rooms, an IntelliStation system performs its functions in complete discretion; it is a digital mixing and recirculating system developed by Powers, a division of Watts.
“It’s a safer, more energy-efficient way to deliver hot water over a much narrower temperature range,” said Bruce Fathers, Product Manager at Powers.
A “smart” control module, with a 3.5-inch color touch-screen interface, displays nearly 200 critical data combinations, including the output temperature of the water mixture, as well as the flow rate. mixed water and back and energy consumption.
“In terms of installation,” Mr. Fathers adds, “we really like the” plug and go “formula. “
Contractors have only five connections to install: hot and cold water supply, mixed water outlet, return and boiler. Then there is only the power supply. At this point, the IntelliStation system automatically controls the output temperature without much additional effort on the part of the contractor. It only takes a few minutes to activate the IntelliStation system.
“The engineer knows that the work is well done, because we assemble it, we submit it to tests, we calibrate it and we ship it. Everything is in line with their specifications, “says Fathers.
Numerically controlled mixing represents an automated solution that replaces an approach largely based on a mechanical process over the last century, requiring much effort to ensure that systems are properly balanced.
“I knew that the digital IntelliStation approach would be a more accurate way to power the Ackerly in hot water,” said Clifford M. Hood, an engineer at Hood-McNees Inc. in Portland, Oregon. specified the system. “Estimating the amount of hot water needed for a building of this size still requires a lot of trial and error and some of our calculation bases are 40 years old. “
No matter the challenge, residents’ expectations must be met. “It costs a lot if there is not enough hot water,” says Hood. “If there are none, the entrepreneurs and the owners, in short, everyone fall on my back. I dare not take shortcuts on hot water. “
The IntelliStation module includes a comprehensive programmable system that monitors temperature, flow, and pressure data from sensors on hot and cold water intakes, mixed water outlet, and return flow. mixed water, or nearby. A high-speed electronic actuator, activated by an integrated control module, modulates a simple three-way ball valve that allows the temperature set point to be maintained permanently.
“The IntelliStation module automatically balances 10 times per second, 365 days a year,” said Dan Checri, director of business development – faucets and blenders, West Region, at Powers. “No Thanksgiving. No Christmas. No vacation. “
Dan Checri, Director of Business Development – Faucets & Blenders, West Region, at Powers, explains the IntelliStation module at a recent educational event presented by Watts and its local entertainment agency, Hollabaugh Brothers & Associates. the Space Needle tower in Seattle.
This numerical approach even exceeds the requirements of the ASSE 1017-2009 standard, which defines the performance of mixing valves used for hot water distribution.
In the case of large diameter valves, designed for a flow rate greater than 40 gallons per minute, the standard requires that they maintain the temperature at plus or minus 7 ° F. In other words, if the set point is 140 ° F, the valve must maintain the water temperature between 133 ° F and 147 ° F, a range of 14 °.
On the other hand, the numerical control mixture allows a much more precise regulation and a maintenance of the setpoint to more or less 2 ° F.
The digital approach represents a significant change in the way engineers and contractors regulate and supply water in large buildings. The most common traditional method is the use of thermostatic mixing valves, which still account for around 90% of the numerically controlled mix in the commercial / industrial market.
Some of the first large capacity mixer taps were developed in 1919. Powers was the first company to use paraffin for the control of large diameter thermostatic mixers (TMV); other mixers are provided with an ether-based or bimetallic control.
“We have developed the IntelliStation module to improve safety and performance, as well as digitize a process that has so far been largely mechanical in nature,” says Fathers.
Thermostatic mixers (TMV) and numerical control
The principle of TMV is easy to understand. In a mixing valve, the temperature fluctuates according to the temperature and pressure of the water at the inlet, as well as the demand to which the system is subjected. The heat is transmitted to the active element through the walls of the sensor. The element expands and changes the relationship between hot and cold water. As the water heats up, a piston moves upward, closing the hot water supply and opening the cold water supply to maintain the temperature set point.
However, the proper functioning of a TMV requires proper design and balancing of the system. It operates at its best efficiency under ideal conditions, when the supply pressures are identical and when the differential pressure between the inputs does not exceed 20%.
“When using a TMV for the regulation of water temperature, problems may arise in case of simple seasonal variation of water temperature or mechanical failure of the various devices installed in the distribution system,” said Matthew Fratantonio, senior program manager at Powers during a presentation at the 2016 ASPE Congress and Expo in Phoenix.
Mr. Fratantonio also mentioned the wrong choice of faucet as another difficulty.
“In fact, the engineers specify valves with a capacity greater than that required as a precaution,” he explains. “But at low flow rates, these mechanically actuated valves have difficulty in providing adequate temperature control. “
In collaboration with Powers and Watts, Plumbing Engineer recently presented a webinar on digital mixing technology. In this presentation, Todd McCurdy, Director of Business Development – Faucets & Mixers, West Region, Powers, highlighted some of the disadvantages of TMVs:
- They cause a “temperature shift” during periods of low or no demand, especially at night.
- They require regular checks and maintenance to avoid performance issues.
- TMVs tend to be vulnerable to chemicals in the water because the control element is immersed in water.
- They can not communicate with an Automated Building Management System (BAS).
- The IntelliStation module, a digital water mixing and recirculation system developed by Powers, a Watts brand.
- TMVs have a high approach temperature – up to 25 ° F. Therefore, the temperature of the incoming hot water must be at least 25 ° F higher than that of the mixed water at the outlet, which is not very efficient.
If, in a water installation, TMVs can be compared to dial phones, then digital mixing devices are like iPhones. Technology has evolved considerably.
Ross Tapani, President, Alex Massie, Foreman and Eugene Likhonin, Finishing Foreman, Tapani Plumbing, and Cliff Hood, Engineer, Hood-McNees Inc. This was the first time that the contractor and mechanical engineer had installed and specified the IntelliStation system.
The IntelliStation module is easily configured on site and requires no proprietary software or laptop. Integrated into an automated building management system (BAS) using BACnet and Modbus protocols (included in the control module), the IntelliStation lead-free system is compatible with integrated building management. Depending on the configuration, the monitoring and regulation of hot water in the building can be done remotely.
“We have installed tons of mechanically controlled taps,” says Ross Tapani, President, Tapani Plumbing, Battle Ground, Washington. “These are hard to tame animals, but we did it. We know how to connect them to the piping and make them work. “
The Ackerly system is the first IntelliStation module that the mechanical contractor has installed.
“We ended up feeling comfortable with TMV,” says Alex Massie, Foreman, Tapani Plumbing. “But it seemed to us that the IntelliStation system was going to eliminate a lot of trial and error. “
This was true in any case for the start-up process.
Eugene Likhonin, finishing foreman at Tapani, reports that he could easily spend a big eight-hour day tuning and balancing a mechanical system to get the right values.
“I could spend a lot of time adjusting a faucet by turning it 1/16 inch, thinking I did well – and the water was getting cold! I always fight big-diameter and small-diameter mixing faucets – not to mention the problems of the differences between a new half-occupied and a fully occupied building, or where there is heating or where there is no heating. ‘there is not any. With the IntelliStation system, I just turned it on and off. “
Legionella and burns
Our focus is on the “everyday” benefits of a reliable supply of potable water through the IntelliStation digital control system.
However, today we need additional protection. Indeed, people live longer and decide to spend their retirement years in large institutions like the Ackerly. At the forefront of the benefits of the IntelliStation module for such institutions is its ability to reduce the high risk of Legionella.
According to the Centers for Disease Control and Prevention (CDC), 8,000 to 18,000 people in the United States are hospitalized each year because of Legionnaires’ disease, a disease caused by the Legionella. The risk of having the disease increases in people over 50 years old.
The IntelliStation system works among other things in disinfection mode with high temperature purges, a way to mitigate the risks associated with Legionella and other bacteria in the water. Once the disinfection process is complete, the system reboots and rebalances automatically.
“The best defense against diseases like that of the legionnaire is obviously hot water,” said Fratantonio during his presentation at ASPE. “Produce hot water of good quality and kill the disease. But it is of course a question of balance. You do not want to exceed 120 ° F because you do not want to hurt anyone. But you still need to go above 120 ° F because you do not want pathogens and other microbes to harm someone. This is the dilemma that schools face. “
By balancing the need for Legionella protection with the provision of warm water at the point of use, the IntelliStation system also helps prevent burn injuries, slips and falls all caused by burns. years by thermal shocks.
Energy and performance
Above all, we mentioned the accuracy of plus or minus 2 ° F obtained with the numerical control mix. Here are some other benefits related to energy and performance:
- It is possible to have precise temperature control even during periods of low or no demand, a result superior to that obtained with TMVs. This level of precision allows for effective management of plumbing installations and enhances building safety.
- Sophisticated communication capability ensures close monitoring and precise control of the system, providing facility managers with the ability to track changes and react accordingly, providing a safe and secure way for building occupants. This type of connectivity is an example of what is known as the “Internet of Things”, a growing market that is expected to generate $ 8.5 billion by 2020.
- Finally, digital systems offer the opportunity to conserve energy and reduce costs. This is a significant advantage, particularly given the amount of energy consumed by commercial buildings, accounting for 19% of the energy consumed in the United States, and it is estimated that 30% of this energy is wasted.