Johnny Tundra--Cold Weather Engineer
"Your energy problem isn’t in your boilers; it’s in your pipe chase!"--Johnny Tundra
By Ron Wilkinson, PE
Johnny Tundra was headed home after finishing his latest commissioning project in Miles City, Montana, and it was a long drive to his Big Timber bungalow. The flat prairie highway stretched out ahead of him was packed with snow and ice and was flanked on both sides by frozen and forbidding mesas. The setting sun poked over the Crazy Mountains to the west and shed a frosty stream of light through the frigid December air. The cab of Johnny's truck, the International Harvester Scout, was warm despite the outdoor air temperatures hovering around zero.
As usual, Johnny was traveling with Gas Train, his 15-year-old Bassett hound. As they needed a break from the drive, Johnny decided to stop at the Fish and Wildlife Region 9 headquarters for a cup of coffee with his old pal Virgil "Eggshell" Coggeshell. The nickname Eggshell alluded to his friend’s bare pate, and Egg always returned the kindly allusion with his own nickname for Johnny, which was "Hard Luck," in reference to Johnny’s failure to fill his deer tag for six seasons in a row.
The Fish and Wildlife headquarters had been remodeled the previous summer, and the former two-story office building now boasted a third floor. Johnny checked out the new structure, as he maneuvered the Scout between the snow drifts. The whole building had been repainted, and the new synthetic tile roof looked spic and span in the bright afternoon sun.
"Hey, Egg, how’s it goin’?" Johnny yelled out the window.
"Just peachy, Hard Luck!" Virgil called back. "I got a completely new roof, all new attic insulation, and a new boiler. But, my natural gas bills have doubled so far this winter. We expected a little more energy use because of the addition of the third floor, but we also expected the new insulation and boiler to cancel that out. Instead our consumption skyrocketed. The boiler vendor has been down here three times in the last three months and swears the boiler is working fine."
"If you can steer me to a cup of Joe, I might just eyeball your boilers and see what’s cooking, if anything."
As the two walked toward the boiler room, Virgil told Johnny about the remodel project. As the new third floor was added, several energy-conservation measures were implemented. For starters, the old oil-fired steam boiler was replaced with four modular gas-fired hydronic (hot water/glycol) units. The existing steam and condensate lines were checked for scale and found to be serviceable. The old steam line was large enough to serve as the supply for the new hydronic system, but the condensate line was too small. So, a new hydronic return line was installed in the existing pipe chase from the boiler room to the third floor.
The existing domestic water line in the chase was found to be leaking badly but was inaccessible for repair. So, after a good cleaning, the old condensate line was used as the new domestic water line. A new heat exchanger was added to the boiler system to heat the domestic water.
Reusing the old pipe chase took some ingenuity, as it was bricked into the center of the building. The contractor continued the chase up to the third floor and installed the new pipes required.
Walking into the boiler room, Johnny gave the boilers and piping a quick once-over.
"Best boilers in the business," Virgil stated. "l built from the ground up to save energy. But, they aren't saving any energy here!"
Johnny walked over to the new domestic water-heat exchanger and glanced at the old brick entrance to the pipe chase. He put his hand on the domestic water circulation pump. "Run the circ pump all the time do you?"Johnny asked, as he waved his hand in front of the opening into the chase.
"Sure," came the reply. "It uses so little power. It costs more to put a timer on it than it's worth. Believe me, electricity isn’t the problem here. Our electricity bill came down just fine, when we pulled out that old electric water tank. It's these blasted boilers that are eating me alive!"
"Eggshell, is there an access hatch to the attic above that new third floor?" Johnny asked. "Your energy problem isn't in your boilers; it’s in your pipe chase!"
"Johnny, this time you’ve truly lost your marbles," Eggshell replied impatiently. "But, if it’s the attic you want, it’s the attic you’ll get."
The two climbed the stairs to the third floor, and Virgil opened the janitor’s closet and pointed out the ladder to the attic. The two climbed up and squatted on the plywood platform above a sea of insulation over the third floor ceiling. Johnny could see the last fading light of the afternoon coming in through the soffit vents. They waddled over to the top of the pipe chase.
"Look down there, and tell me what you see," Johnny said.
Virgil peered down the chase. "I see a light," he said. "How did that get there?"
"That’s my flashlight," Johnny said. "I put it at the bottom of the chase. You’re looking straight down three floors to the boiler room. Feel that draft?"
"Boy, I’ll say," Virgil exclaimed. "How did you make that wind tunnel?"
"I didn’t make anything," Johnny replied. "That wind tunnel has been here since last summer. When your contractor added the third floor, he removed the cover over the old chase and extended it up to this level. Unfortunately, he neglected to put on a new cover when he finished.
"The frosting on the cake is the old condensate pipe down there. The contractor had to extend it up, too. And, he insulated the new portion, just like the specs said. But the old portion was never insulated. The original building designer figured energy was cheap, and what little heat was left in the condensate line would heat the building anyway. So, it was left bare during the original construction. When the pipe was extended, the contractor had no access to insulate the old pipe. Because the specs didn’t call for it to be insulated, he left it, as is.
"So, what you have now is a 20-foot length of uninsulated pipe that is kept hot 24 hours a day by your domestic water heat exchanger and circ pump. Even worse, you have a 30-foot chimney of heated air that is sucking the hot air out of your building and exhausting it to this vented attic space where it quickly dissipates to the outdoors. You couldn’t have designed a better hot-air exhaust system, if you tried.
"I knew something was wrong when I drove into the parking lot and saw the snow had melted off the new roof. You’re trying to heat the entire eastern half of Montana. If you seal the top and bottom of this chase and put that circulation pump on an eight-hour-a-day, five-day-a-week schedule, I bet you’ll see those energy savings come back."
"Well, as much as I hate to say it, Hard Luck, looks like you hit the bull’s eye again," Virgil sighed with relief. "Even if it is the first time since the start of hunting season!"
Johnny Tundra--Cold Weather Engineer