Hydronic heating gets ‘smart’

 

BY JOEL WILLIAMS

 

Today, some form of comfort system automation is available in most new homes. But more than programmable thermostats and outdoor temperature sensors, the future of home automation is found in so-called “smart controls.” By “smart,” we mean the ability to manage all of a building’s heating, ventilation and air-conditioning (HVAC) systems — radiant, forced air, domestic hot water, snow- melt, etc. — through a single network control system.

 

“Smart controllers are perhaps the single biggest opportunity for plumbing and heating contractors going forward,” opines Ted Lowe, executive director of the Radiant Panel Association. “The new technology offers self-configuring networks that require no programming, software or web knowledge, which gives the average heating contractor unprecedented access to this market.”

 

Most HVAC and hydronic heating manufacturers already equip individual components with varying levels of “stand-alone”-type controls. These controls are intended to moderate a specific application or purpose (e.g., resetting a boiler, controlling a mixing device, etc.)

 

But while a boiler, pump or furnace might contain individual efficiencies, there are even greater system synergies to be gained when HVAC and related climate control systems are centralized, argued Robert Bean, a registered engineering technologist and the editor of the Journal of Indoor Environmental Quality.

 

To illustrate the focus toward integrated systems, Bean asks rhetorically: “Should there be an air traffic control tower operating in isolation for each plane? Or is it better to have several controllers inside one tower, together integrating the management of air traffic?”

 

Indeed, Lowe says that systems using centralized, smart control technology are able to reduce energy consumption by 15% to 30% in most applications. When you consider the current and future cost of energy, this level of savings is a powerful investment for homeowners and building owners to consider.

 

And yet, given the multitude of equipment manufacturers and proprietary communication protocols, this concept of a universal, all-knowing control has been elusive until recently — especially for smaller, noncommercial applications.

 

The Holy Grail: Intelligent integration

 

The ability to communicate or “network” among controllers, sensors and components is a key difference between past and future generations of HVAC controls, according to Jeff Wiedemann, product manager, application controls for Uponor, Inc., whose company markets one such “smart” controller.

 

“In the past, contractors might have had one control box for boilers, one for mixing, one for snowmelt — all built by the same manufacturer — and all unable to talk to one another,” said Wiedemann. “Our Climate Control Network™ System changes that scenario and links a variety of different systems and dissimilar equipment under one central control, using intuitive graphical configuration tools that replace complex and time-consuming programming.”

 

Imagine, he said, the ability to automate intelligent, energy-efficient choices without intervention from home or building owners. “It would be a nightmare, using conventional controls, to choose the heating device with the lowest operating cost from among a multiple-stage geothermal unit, solar collectors and a high-efficiency condensing boiler,” admitted Wiedemann. But that same task becomes much easier, yet more costly, using direct digital controls (ddc).

 

“The clear choice,” Wiedemann continued, “is the new generation of HVAC controls that can detect all the available heating devices in a home and automatically select the one with the lowest possible energy consumption.”

That’s not to say that smart controllers solve all HVAC problems.

 

“Contractors still need to understand the mechanics behind smart control technology,” said Dave Yates, president of York, Pa.-based F.W. Behler, Inc. “For example, an apartment complex I visited last week had two efficient boilers, but the contractors didn’t install an outdoor temperature sensor to allow the boilers’ internal diagnostics to operate efficiently. As a result, the system was running at only 87% efficiency instead of 95%. We must not miss the low-hanging fruit in our attempt to reach the top of the tree.”

 

Manage energy — automatically

 

Energy efficiency is achieved through both electromechanical solutions (e.g., valves, dampers, pumps), as well as power and fuel conservation, said engineering technologist Bean. “Working alongside a radiant-based HVAC system, smart controls can maximize efficiency by intuitively managing the various temperatures in the space and in the systems, as well as managing the power and fuel consumption.”

 

Consider a mixing function for which the controller must determine the optimal water temperature. Instead of basing this decision solely on one input (e.g., the outdoor air temperature), today’s newer controls leverage multiple data points (outdoor temperature, supply water temperature, valve position, pump speed, etc.) in order to supply the lowest — that is, the most efficient — water temperature necessary.

 

In addition to conserving power and leveraging data to make informed decisions, today’s sophisticated HVAC controllers are able to maximize the energy savings associated with variable speed outputs, or ecms (Electronically Commutated Motors). In other words, why operate a pump at full power, if a task can be achieved with just 30% of full capacity?

Noted Yates: “My home’s hydronic variable speed circulators utilize ecm motors with inverter variable-speed technology that, combined with my three-watt zone valves, have slashed my thermal-transfer power consumption by more than 90%.”

And today’s smart controllers do just that, right out of the box. From one central control, contractors are able to control two stages of heating, two stages of cooling and supplemental heating, as well as allow changes to room set-point temperatures and humidity set points, while also controlling the fan and heat recovery ventilator (hrv).

 

The control technology is so broad, in fact, that contractors and design engineers are now able to consider total system efficiency, instead of focusing on individual contributors, said the RPA’s Lowe.

 

“It’s like saying that a home is well insulated, but has poor-quality windows,” said Lowe. “You can’t separate the two, because they both contribute to energy usage and homeowner comfort. Moreover, from an energy standpoint, systems are only as efficient as the controls, and poor controls waste energy, increase life cycle costs and reduce occupant comfort.”

 

Always watching

 

Bean noted that smart controls can serve as the contractor’s permanent on-site manager. “When properly applied, these controls can reduce the field technician’s on-site time in commissioning, operation and maintenance,” said Bean. “They can also serve as an early warning system for component failures or to help optimize energy use.”

 

Uponor’s Wiedemann agreed and pointed to a popular feature on his company’s Climate Control Network that permits a service contractor to monitor a customer’s network online, while making rapid-response changes to meet comfort needs.

“A service tech could conceivably know about a service issue — via cell phone or e-mail alert — before the occupants do,” Wiedemann remarked. “This, in turn, eliminates the inconvenience and hassle of having to make a separate service call and greatly boosts customer satisfaction levels.”

 

This new generation of smart HVAC controls simplifies integration, monitoring and maintenance of different systems, while yielding better energy efficiency and, ultimately, better occupant comfort and convenience.

 

Some additional “smart control” features include:

 

• Scalability: The flexibility of these modular control systems enables plumbing and heating contractors to accommodate any size HVAC system and to incorporate additional elements down the road.
• Accessibility: To view or change system status remotely, users can access their centralized controller via laptop or smart phone.
• Trends-monitoring: The ability to sample, store and read trends enables users to fine-tune system efficiency, as well as troubleshoot potential problem areas.
• Master-passing: Smart controls offer the ability to transfer system command to any thermostat within a system.

While most HVAC systems are designed prior to construction, the scalable nature of smart controls make them ideally suited for new work, expansion projects, or to incorporate a greater level of control over existing mechanical systems. The modular nature of most smart control technology make these systems compatible with most budgets, as well as amenable to future changes.

 

Finally, contractors can leverage classroom and on-site training to get the most performance from their chosen control system.      

 

Joel Williams has been a freelance writer for 18 years and has written extensively on new technologies, trends and product innovations for the home building and DIY marketplace. Joel can be reached at

Joel_Williams@sbcglobal.net.