Is the United States on the verge of a new age of hydronics? Smarter and more energy-efficient hydronic technology similar to what has evolved in Europe over the last several decades is getting a new look from system designers seeking to design larger buildings to new environmentally conscious standards. With technology, fewer materials are required for HVAC-system performance, and less energy is consumed during operation.

Proof that a new hydronics age has arrived includes:

• Hydronically driven chilled-beam cooling systems have entered the U.S. marketplace. Their low-profile systems wick away British thermal units quickly.
• Radiant heating and cooling systems have moved beyond their probationary period, offering efficiency and quiet/ reliable operation.
• Modern fan coils are more capable and durable than their ancestors. They can be connected to boilers, water-source heat pumps, geothermal systems, or ultrahigh-efficiency modular chillers to deliver comfort year-round.

This article will focus on modulating-condensing boilers, which have achieved near-perfect efficiency levels. What was inconceivable just a decade ago is now a reality.

The Costs of Energy
The silver lining to the energy crisis is that consumers have a newfound awareness of and appreciation for the financial and environmental costs of energy. Also, the market is learning that the rewards for investing in new technology can be significant.

"There's no question that the 'green movement' is here to stay," Chuck O'Donnell, product marketing manager for Rochester, N.H.-based Laars Heating Systems Co., a subsidiary of Bradford White Corp., said. "It's been a powerful market driver, slowed only by the downcast economy. But the Europeans and some Asian countries have shown us the power and positive influence of a 'green infrastructure,' ... and our government's incentives to go green have at least given new energy to the effort, despite economic woes."

The newest generation of hydronic equipment—such as condensing technology that extracts heat from condensate—recovers heat that used to go "up the chimney" for hydronic use, pushing combustion efficiency into the 95- to 99-percent range. Additionally, hydronic equipment can be fitted with new and sophisticated controls and integrated with a building-automation system (BAS).

With this kind of efficient performance, building owners are coming to attention. When a design engineer can calculate a three- to four-year payback for new equipment, there is incentive to install new technology.

System Efficiency
How effectively a boiler relates to a system is determined by how fast it can deliver heat, which depends on system needs and the boiler's ability to adjust to demand changes (commonly referred to as "sizing to load"). Total system performance is enhanced when equipment works at peak performance—when fuel is consumed at peak combustion efficiency—at all levels of heat demand.

Additionally, more-sophisticated controls can sample modifications over time and "learn" a system's responses to changes in conditions, such as heating load, outdoor-air temperature, and boiler firing stages.

"And, of course, there's modulation or staged firing vs. on/off," O'Donnell said. "Modulating and staged-fired boilers reduce fuel consumption by sizing to the load so that the amount of heat produced by the system precisely matches the need."

Maintenance and Smaller Systems
O'Donnell explained that recent boiler-technology developments include higher efficiencies for combustion, as well as electrical (amp) draw from pumps, blowers, and valves. However, advanced high-efficiency heat-exchanger technology can require more maintenance scheduling.

"In order to keep condensing heat exchangers running optimally, they must be inspected and cleaned yearly," O'Donnell said. "Otherwise, there's likely to be a decrease in output efficiency and a reduction in fuel-usage savings."

The market also is moving toward smaller boilers as heat-exchanger-design technology improves.