Smart HVAC: Manufacturers Try Hard to Make Zoning Easier to Install
“The HVAC industry is the last holdout when it comes to accepting zone control as a viable product,” said Dick Foster, president of Zone First. “For more than 50 years, zoning has been standard on every hydronic heating system using zone valves or circulators. Electric baseboard heating was an easy and popular method of zoning, except for the cost of electricity.
“Today, the modern radiant in-floor heating units are all zoned. Even auto industry commercials talk about offering individual driver and passenger temperature controls or multizone climate control for each row of seats.
“Why is it taking so long for the residential and light commercial HVAC market to wake up to the fact that zone damper systems can provide temperature control, save a tremendous amount of energy when used properly, and add value to the cost of the HVAC system and the overall home?”
MAKING IT SIMPLERAt the 2007 Air-Conditioning, Heating, Refrigerating Exposition (AHR Expo), Foster featured his company’s new H3 zone control panel, designed to control single- and two-stage heat pumps plus dual-fuel systems all from one control panel. According to Foster, built-in switches can be field set for each specific type of equipment.
These new motors also have light-emitting diode (LED) position indicators that light green when the damper is open and red when the damper is closed. The control panels also have the modular jacks for wiring in the dampers and LEDs that indicate the system status of the calls for heating, cooling, fan-only, and individual zone LEDs to show when each zone calls.
The panel has a built-in dual-fuel kit and remote sensors for outdoor air sensing for dual-fuel systems, he said. In addition, it also has a “leaving air” sensor for zoning applications. “The panel is simple to wire, using push-in wiring blocks, eliminating the need to screw in each wire,” said Foster. “All wiring blocks are color-coded to avoid wiring mistakes. The color-coded blocks make it easier to wire by matching the thermostat and HVAC equipment color codes to the thermostat wires.
“Also, these colored blocks make it easier to see where the wires go, especially when in a dark basement or attic with low lighting. Installers report time savings of 30-40 minutes per job over panels with single-color screw terminal blocks.”
Zone First also offers a motorized bypass damper that uses a static pressure sensor and a modulating damper to automatically compensate for the variations in static pressure that occur when zoning. As zone dampers open and close to provide air to the different zones, the static pressure in the duct system can vary greatly. “This is especially true when using a variable-speed blower,” said Foster. “As zone dampers close, the blower will speed up to maintain a constant airflow through the HVAC unit. Ideally, when zoning, the blower needs to slow down. However, since typically it speeds up, a bypass is used to compensate for the excess air. An automatic motorized bypass that can respond to the changes in the duct static as the zone dampers change position is a smart way to bypass.
“Automatically as the duct pressure increases, the bypass will open to relieve excess air pressure, keeping the variable-speed blower from increasing. This smart device automatically compensates for the airflow as changes in the zone dampers occur. As zones close, the static sensor senses the rise in air pressure and opens the bypass to keep the air pressure low. As zone dampers open, the bypass closes to keep air pressure in the ducts and directed to the calling zones.”
DOING ITS PARTArzel Zoning Technology Inc. is the maker of the HeatPumPro™, an integrated zone-control panel for high-efficiency heat pumps. It is designed to save hours on control strategy and wiring. Control features include the Set-Up Wizard, which makes commissioning possible with the touch of a button, saving hours on control strategy and wiring, according to Mark Votaw, vice president of zoning products at Arzel.
“SmartStaging™ is designed to control equipment capacity based on thermostat demand or variable load requirements,” he said. “The Zone Weighting control matches cfm output to available duct capacity, minimizing bypass requirements.”
HeatPumPro also provides dehumidification and humidification integration while the LCD screen provides real-time reporting on the entire system, he said. The HeatPumPro is available in two-, three- and four-zone configurations.
Arzel also offers Zonocity™, a high-velocity zoning system “for the most challenging architecture.” Votaw said historical buildings, structures with architectural constraints, or buildings that incorporate radiant, steam, or hot-water heating are a match for a high-velocity cooling system and Zonocity. “Zonocity adapts these technologies and controls them to provide an even greater level of comfort in every area of the home or office, many times with just a single air handler,” said Votaw.
Zonocity consists of branch dampers, trunk feed, high-velocity air handler, patented 2-inch damper, and the Ezyslide™ trunk damper. In the end, Votaw said Zonocity could integrate up to three zones with a hydronic or any other secondary heating source “so that one control can be used in all seasons.” If you add a zone valve interface, it can integrate small-duct, high-velocity (SDHV) cooling with radiant, hydronic, or steam heat, too. Votaw said there must be a minimum of 3.5 outlets per ton in each zone.
MORE POSSIBILITIESDuro Dyne Corp. recently introduced several new DuroZone products, including its 24-V, spring-return, multiblade damper; 24-V, spring-return, multisize damper; and its round, spring-return motor damper. The company also featured its new ED3 and ED4 zoning panels at the AHR Expo.
In regard to the multiblade damper, it can be placed inside ductwork to control airflow in warm air and air conditioning systems. The multisize damper has a single-set screw that secures the motor. Ten models are available, in heights of 6 to 14 inches. The return motor damper is available from 4 to 20 inches in diameter.
Meanwhile, the new line of cable-drive zone balancing dampers from Ruskin Air and Sound Control keeps expanding. The ZMDRS25 is the latest addition to the company’s cable-drive products. The rugged frame design has rolled-stiffening beads, designed to assist in sealing, “making this a perfect solution for spiral duct applications,” said the company. The damper blade is mechanically fastened to a 3/8-inch-square shaft, held at each end with synthetic sleeve bearings that are molded to the axle shape, designed accordingly to reduce duct leakage. The unit comes standard with a 3-foot-long cable and worm-and-gear drive.
“The smarter and simpler we can make zoning, the easier it will be for the installer to accept installing zoning,” concluded Foster. “However, it is still up to the person making the sale whether or not to offer it.
“There are still the misconceptions that zoning is expensive, does not work, and is not needed, when totally the opposite is true. What lies ahead are millions of opportunities every day for every installer of HVAC systems to put in zoning, and those who do not miss out on truly providing the best system for their customers and lost profits.
“For every new installation or changeout not installed with zoning is leaving money on the table in lost sales and profits for the installer, as well as lost energy savings and comfort for the end user of that system.”
Publication date: 04/23/2007