Soda Can Solar Furnace Helps Cut Heating Bills
When residents of Westwood, a low-income neighborhood in Denver, were asked what would help them the most, the answer was simple: Help us lower our utility bills.
Engineering students at Metro State University took up that challenge. They designed a furnace that uses recycled materials, is solar powered and costs less than $50 to build — and pennies a day to run.
From the Here & Now Contributors Network, Jenny Brundin of Colorado Public Radio found out how the design is working.
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When residents of Westwood, a low-income neighborhood in Denver, were asked what would help them the most, the answer was simple: Help us lower our utility bills. So engineering students at Metro State University took up that challenge. They designed a furnace that uses recycled materials, is solar-powered, cost less than $50 to build and pennies a day to run.
From the HERE AND NOW contributor's network Colorado Public Radio's Jenny Brundin found out how the design is working.
JENNY BRUNDIN, BYLINE: At the end of every month after his daughter pays the bills, 73-year-old Jose Pitones says...
JOSE PITONES: (Spanish spoken)
BRUNDIN: ...there's nothing left over. He and other families in this southwest Denver neighborhood are barely scraping by. In fact, many here report an income of less than $17,000 a year.
ERIC KORNACKI: One of the first things you notice when driving through this neighborhood is the poor housing stock.
BRUNDIN: This is Eric Kornacki, executive director of the neighborhood-based group Revision International, which helps families here be more self-sufficient.
KORNACKI: Many of the homes here are terrible in terms of heating, so a lot of families spend a big portion of their budget on trying to heat their homes.
BRUNDIN: Revision enlisted students at Denver's Metro State University to meet that challenge. They designed a low-cost solar furnace, simple enough that families themselves could build it, install it and replace it. The students started with a surprising but familiar material. You know that aluminum soda pop can you toss into the recycle bin? Turns out it's an excellent heat conductor.
RICHARD ANDERSON: The hard part is getting the tops and the bottoms off.
BRUNDIN: Metro State mechanical engineering student Richard Anderson helped build a mechanism that pops out the tops and bottoms of 144 cans in 40 minutes. That's the number needed for one solar heating unit. They're set in a wooden frame, like a big bookcase. The unit pulls air from the house and funnels it through the cans. The sun warms up the air, and a computer fan pushes the air back into the house.
At first, families were skeptical, so was Revision International's Eric Kornacki.
KORNACKI: How is this thing actually going to work? It has soda cans and a computer fan and some spray paint, you know? But after feeling the heat coming out of it, we were sold.
BRUNDIN: Revision still had to sell the idea to the community. What helped was Revision's promotora model. The nonprofit employs women from the community who know how to network and can help convince residents to get on board.
KORNACKI: If a promotora is sold on the idea, they sell the community.
UNIDENTIFIED MAN #1: This is yours? Where's the cord?
BRUNDIN: On a sunny winter morning, the student engineers and the promotoras arrive at Jose Pitones' house. But something's different from when they scoped out the house in the summer.
ZYOLA MIX: This is one that has caused us the most grief.
BRUNDIN: Student Zyola Mix says the sun isn't in the same place in the sky as when they made their first visit. They thought there would be more sun hitting the backyard than there is.
MIX: Yeah. I should have used the app on my phone to determine the sun angle for the winter, but I did not.
BRUNDIN: They find another vent on the roof to attach the furnace to, but there's a large juniper tree next door that partially blocks the sun.
MIX: Shadow, it's going to...
UNIDENTIFIED MAN #2: Yep.
MIX: ...go over for two to three hours on this thing.
UNIDENTIFIED MAN #2: Yeah.
MIX: So we want morning...
BRUNDIN: The students discuss adjustments and cut an insert into a piece of wood that will bring air into the unit. Many of these engineering students will eventually get jobs on big projects with big firms, but the chance to help out a struggling community has made this project especially worthwhile for the students. Here's Zyola Mix.
MIX: I grew up also needing a lot of help. And so it's just nice to be able to help other people. It makes me feel like I'm still involved in the world and I can see how it is improving.
AARON BROWN: OK.
UNIDENTIFIED MAN #3: Is it running?
BRUNDIN: After a couple hours of work, the solar heater is finally plugged in.
BROWN: There you go. Preheat.
BRUNDIN: Metro State University assistant professor Aaron Brown tells a neighbor the solar heaters save on average about $25 a month on heating bills.
BROWN: One cent a day.
UNIDENTIFIED MAN #3: One cent. That's good.
BRUNDIN: (Unintelligible) one cent.
Jose Pitones' daughter, Rafaela(ph), says she's excited about the money they'll save.
RAFAELA PITONES: (Spanish spoken)
BRUNDIN: She'll use the extra money for a trip to the grocery, on milk run, or even to pay other bills.
UNIDENTIFIED MAN #4: Thank you.
PITONES: Thank you.
PITONES: Thank you.
BRUNDIN: As the sun continues its arc across the sky, the Pitones family and the students shake hands and offer thanks. Metro student Richard Anderson knows the impact of this furnace will go beyond saving a few dollars. He remembers a child's reaction after installing a solar heater in another home.
ANDERSON: And I walked into the bedroom and the little boy that had that bedroom turned to me, and he had the biggest grin on his face, and he's like, I'm going to sleep so nice tonight because it's so warm in here. And I was like, well, that's it. That's all I needed to hear.
BRUNDIN: For HERE AND NOW, I'm Jenny Brundin, in Denver. Transcript provided by NPR, Copyright NPR.