Over thirty five years ago, I saw an article about building features that used passive solar energy. I remember the drawing of a home's eaves that extended beyond the south-facing windows to block the summer sun from entering the house, but permitted the winter sun to enter because it takes a lower path through the sky. The article also pointed out the benefits to using the earth - building into a hillside or partially underground - to help keep the house cooler in summer and warmer in winter (I've read that caves, deep underground, are a constant fifty five degrees year-round).
Passive solar features add little, if anything to the cost of building. Adding a small investment in active solar - hot water and photovoltaic - and homeowners can harness the power of the sun to reduce their energy consumption and save money.
From
The Fairbanks Daily News:
Sunlight poured into a large south-facing window and drenched the stained concrete floor, stones and flower beds in warmth. Like batteries, these features capture, store and dispense energy to the 2,300-square-foot house year round. Sun coming through the window has provided all the home’s heat since mid-February.
Outside, a dozen solar thermal panels stared at the Alaska Range and drank in the mid-morning sun. The panels and a stone masonry heater (complete with a bake oven) are the only heat sources in the home.
“You wouldn’t believe how many engineers have told me in the past year that it’s impossible,” Thorsten Chlupp said of the fossil-fuel free system. “I already know I need to build an outdoor swimming pool because I have too much heat.”
Chlupp, a general contractor and owner of Reina LLC, built the home off Old Chena Ridge Road in the fall and moved in with his wife and young daughters in January. The wood-frame house uses local lumber, recycled insulation and sustainable flooring and contains high-efficiency lighting and appliances. While elegant and comfortable, its biggest asset is its insulated thermal mass.
Chlupp designed the house to prove that solar energy, combined with tight construction and proper heat storage, can work even in Fairbanks. It’s poised to be the northernmost passive house in the world (a label for buildings that consume very little energy). He plans to produce his own energy when he adds photovoltaic panels this summer. Chlupp wants to see the design take off in the area. But first he must dispel the myth — among the public as well as building and solar experts — that the heating system won’t work in this climate, he said.
After all, Fairbanks is cut off from solar energy for all of December and January. Yet Chlupp has hoarded so much heat during the past few months that he has burned only one cord of wood. The last fire was three weeks ago.
“We create more storage, and we have the ability to bridge long periods of time when we don’t have sun,” Chlupp said. “In this house we can store eight million BTUs of energy within the tank and within the foundation.”
Eight million BTUs is enough to heat the home for two months.
Chlupp, 37, moved to Fairbanks from Germany as an outdoor and mountaineering guide in 1996. He began building homes 12 years ago and discovered the shortcomings of conventional building in a cold climate. He started incorporating green concepts from Germany, like passive solar and airtight walls, into houses here. But when he pushed for renewables, people said it wouldn’t provide enough year-round energy for this climate and latitude. So he set out to prove the systems were effective and affordable.
Trapping and storing heat
It was 70 degrees inside Chlupp’s house, and 12 solar thermal panels standing nearly upright on his roof were caching away more energy.
“We’re producing 154 degrees off the roof right now,” he said.
His energy system ties wood and solar into a single super-insulated storage tank.
Coils of pipe inside the solar panel are filled with a glycol-based fluid that heats up and circulates wherever it’s needed. On a cold winter day, it flows through loops in the floor slab that slowly emit radiant heat. But when there is no heat demand, it goes to heat water (through a heat exchanger) in the giant tank in Chlupp’s second-floor utility closet.
The 14- by 8-foot stainless steel tank is the master battery. The water can store about 4 million BTUs of energy, Chlupp said. In December, he filled it with 5,000 gallons of 40-degree water. Now the water is between 130 and 150 degrees, unlimited hot water for weeks.
“I would have never believed that we would be able to get that much,” he said. “If I have no sun for two weeks, it doesn’t matter. I have plenty of hot water.”
A smaller 40-gallon tank lives in side the big tank and is used for domestic needs. The rest of the water simply circulates between the tank and heat exchanger, either taking or sharing heat with the rest of the house when needed.
Three coils inside the masonry heater also feed heat to the water tank.
“The masonry heater combined with this tank works like magic,” he said.
The heater is made from four tons of river rocks, experts at soaking up heat, gathered in Healy. They release radiant heat when the air temperature becomes cooler than the rock temperature.
The foundation is also designed to store maximum energy. Below four inches of blue and earthen-toned concrete is 180 tons of sand in an insulated box.
Extra heat is dumped into a 400-foot underground geothermal loop outside, which is used to preheat air used for ventilation.
Minimizing heat loss
Even before Chlupp considered energy input, he designed a house that would hold onto energy.
“That’s the baseline. You have to minimize your heat loss. Everything else comes after that,” he said.
That means 22-inch airtight walls with permeable cellulose insulation — made of 85 percent recycled newspaper — and locally made triple pane windows.
The insulation goes on the outside of the building, like the “remote” wall system tested by Cold Climate Housing Research Center.
There is no vapor barrier but moisture can escape on both sides, avoiding condensation and potential mold, Chlupp said.
Ventilation provides clean air and air conditioning.
Chlupp installed a German heat-recovery ventilator, three times bigger than domestic HRVs, to bring in fresh air.
“We know that anything besides mechanical ventilation doesn’t work here,” he said.
Thermal shutters were also installed for the windows.
“It works like a champ,” Chlupp said, sliding a 6-inch-thick shutter (R-40) across the large south wall, a nightly routine.
Target audience
Chlupp would like this system to be the norm, but first he is working the kinks out (CCHRC is monitoring his house with a grant from the Alaska Housing Finance Corporation). He has installed a half-dozen masonry heaters for clients but has only built one other house with a similar heating system.
His heating ensemble cost roughly 30 percent more than a traditional boiler system. He estimates it will pay off in about 10 years, based on current oil prices (now nearly $4 per gallon).
But he expects to knock the cost down to a traditional heating system within the next couple of years — for both new construction and retrofits.
It would be automated, like any other system, easy to plumb and affordable to maintain. The tank liner, for instance would need to be replaced every 20 years while solar thermal panels last 30-40 years, he said.
Not to mention the free energy.
“What I’m after is replacing everything fossil fuel based, because if we can get rid of it completely we’re so much better off,” Chlupp said.
“Until we have actual houses out there proving it can be done, nobody believes it.”
More power is coming from clean energy than ever beforeG-20 spends most
Use of small-scale wind power is increasingBig production, small projects
