Radiant Heating Report: Left Brain Radiant ... Right Brain Radiant
John Abularrage entered the radiant industry back in "the pioneering days" of 1979 when he did research and development for Bio-energy Systems. The company manufactured a product called the Radiant Roll. Abularrage ran a series of experiments in a specially equipped environmental room to determine sizing guidelines.
He's been involved in other aspects of radiant ever since and ultimately founded the precursor of his current company in 1986. Advanced Radiant Design's business is exclusively radiant, with about 65 percent of the work in residential and 35 percent commercial.
This is the first year the company entered the RPA's System Showcase Award competition. Abularrage took home two first-place awards, one of which appeals to the artistic and the other, the logical.
Hydronic RetrofitIt's hard for this job not to end up artistic since Hill House is designed to house artists-in-residence and provide them studio space for their work.
"It's a meticulous restoration of an old building, with art integrated into every detail," Abularrage says. The 6,000-sq. ft. building originally was a schoolhouse built in 1876.
Two years ago, Advanced replaced an existing boiler with two Weil McLain GV boilers. The vent and the air intake for each was routed through an old chimney cavity and then through three layers of brick in the outside wall. To preserve the appearance of the building, several artists ground up bricks and coated the cover plates with the brick dust. To complete the faux finish, the artists applied mortar lines, continuous with the actual lines.
In 1997, Advanced installed a 5-ton Spacepak air-conditioning system to cool a number of rooms, including the kitchen. The system's 2-inch vents specifically were integrated into the geometric design of the kitchen's original tin ceiling. In other rooms, custom cabinetry helped conceal the outlets.
Advanced has completed a number of radiant jobs at Hill House, with the first done in 1987 when the company installed a radiant slab in the basement. "At the time, we were the only ones in the Hudson Valley doing radiant," Abularrage explains. "If anyone in the area wanted radiant heat, they found their way to us."
The rundown reads like a laundry list of radiant expertise:
- Also in 1997, Advanced installed a high temperature loop to the solarium, where the existing floor prevented the installation of underfloor radiant. The zone consists of two tiers of fin tube installed between the hot tub and adjacent windows. A custom enclosure for the fin tube "catches" the cold air dropping from the windows and heats it before reaching anyone enjoying the hot tub. A Runtal towel warmer also provides heat. Two additional high temperature zones feed hydronic fan coils to heat two artist studios.
- In 1999, Advanced installed a high temperature zone to feed five Runtal radiators in the basement, plus another high temperature zone to heat the hot tub through a stainless steel heat exchanger.
- In 1999, Advanced also installed a system to heat a guest cottage with one zone of radiant staple up. The system also provides domestic hot water and heats two garages with fan coil heaters.
Is there anything left to do? Maybe not for the old schoolhouse, but Aubularrage reports the owners recently purchased a building across the street, built circa 1736. Advanced soon will begin installing radiant for that structure.
Jacobs Residence, Basalt, Colo.
Wetherburn Drive Project, York, Pa.
F.W. Behler Inc.
Hydronic CommercialIf the Hill House job gave the artistic left side of the brain a workout, then Advanced's next award winner pumped up the more logical right side.
The facility's managers of this 10,000-sq. ft. children's day care facility had specific design criteria they wanted met. They required, for example, zone circulators to be standardized to Grundfos 15-42s, with a 10-degree delta T across the tubing.
"Other contractors were bidding the job," Abularrage says, "but we were the only ones with in-house design capability." That made a big difference in responding to the client's demands. Where other contractors went back and forth with their wholesalers for help, playing telephone tag along the way, Advanced was able to deliver answers quickly.
We'll describe the finished system later. But while much of the work was done on site, one of the most interesting aspects of the job was built in Advanced's shop an hour and a half away.
"The system's control panel was pre-piped, pre-pressure-tested, pre-insulated and pre-wired in our shop," Abularrage explains. "We do it for all our jobs; it gives us great quality control."
The panel came apart in two sections, with only three piping connections between the two. All the wiring between the sections were routed to a common junction box.
"We delivered the panel at 9 a.m.," Abularrage says. "By noon, the panel was erected and the radiant zones were connected to it. By the end of the day, all the piping to the boilers and high temerature zones was completed."
Abularrage figures his crew saved 80 man-hours by building the control panel at the shop.
The heating system is designed around two boilers, one dedicated to radiant zones and the other dedicated to high temperature zones for domestic hot water, a reheat coil for the ventilation system and a radiant boost zone. The system is piped with a separate primary and secondary configuration for each boiler.
Six zones were partitioned by similar heat loss and all tubing lengths were kept within 5 percent of one another for flow balancing. To meet the client's demands regarding the Grundfos circulators, Advanced installed 5/8-inch tubing with a 250-ft. maximum tube length. Supply and return mains are 1-inch and 1 1/4-inch PEX.
A tekmar 252 two-stage boiler control monitors the radiant boiler and provides partial boiler reset. The 252 controller also activates a high temperature zone from the high temperature boiler when the radiant boiler is unable to meet the load. Hot water is injected from the high temperature secondary loop into the return line of the radiant boiler.
An outdoor reset strategy controls the radiant distribution supply water temperature with variable speed injection mixing through a tekmar 353 controller. Meanwhile, the high temperature zone is controlled by a relay control. The boiler's operating aquastat controls the high temperature boiler.
Advanced installed test plugs before and after each zone circulator and on the return line of each zone, all of which measured the delta P across each circulator and delta T across each supply and return line. This helps determine the actual flow rates and Btu heat output to each zone.
On all commercial jobs, Advanced documents every aspect of the system's operation. All parts of the system, including wiring, zone specs and control valves are clearly labeled. The labels correlate to the system's schematic drawings and operational descriptions. Before calling it a day, Advanced also conducted a maintenance class to educate the facility's engineers and maintenance crew about the heating system.
Finally, Abularrage made a point of noting he received the first call about this job after the facility's managers got his name from the RPA's Web site.
Illco Inc. Building,
Argyle Fire House,
David T. Sellers Mechanical