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“Just imagine using the sun to create a cooling effect,” says Sam Yang. “Isn’t this a paradox?”
Photo submitted
Solar Cooling
It was this paradox that excited the team at the beginning of the project. Bob De Smith, Paul Kleyer, and Sam Yang envisioned researching absorption refrigeration and building a unit that ran entirely on solar energy. But, they soon ran into snags. “Our plan was to build a prototype,” says De Smith. “But, we soon found that it was hard to design and build it in a semester.”
“Now we’re comparing the different ways you can harvest solar energy for a refrigeration system, trying to figure out which one would be best,” says Kleyer. The team purchased a small absorption refrigerator like those found in RVs and has been running tests ever since. “We wanted to see our project actually work, so it’s been kind of a letdown,” admits Kleyer. But, Yang says, the project has helped the team to think globally, because a solar refrigeration system could provide opportunities for cooling in developing countries. “This technology has a great possibility to improve the lifestyle, economy, and community in developing countries,” says Yang. “Rather than developing technologies that fulfill our desires or wants, we are glad to be a part of unfolding technologies at Dordt that please God by pleasing our neighbors.” “And dealing with things that you realize aren’t going to work and finding ways to make them work by changing them has been very helpful,” says Kleyer. For Sam Yang, who plans to attend graduate school for sustainable energy, the senior project will be directly applicable to his future endeavors. “With problem sets, there’s always a right answer,” says De Smith. “With this
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Paul Kleyer, Bob De Smith, and Sam Yang didn’t get to build the prototype they had hoped to, but they built up a wealth of knowledge they expect to use in graduate school.
Denitrifying Bioreactor
spring,” adds Van Weelden, “we wouldn’t have been able to do any testing on it because we needed water to flow through our reactor after the snow melted.”
“Nitrates in local surface water in Northwest Iowa is a large and growing concern,” says Mark Van Weelden.
But the unusually warm and dry winter and spring in Northwest Iowa had a major effect on their plans.
Nitrates, which often find their way into the local water supply through field runoff, can threaten the environment and, in some cases, human health. Van Weelden and teammates Nathanael Couperus, Steven DeLawyer, and Luke Reznecheck were eager to work with their client, Rural Water Systems # 1 of Hospers, Iowa, to tackle this problem by constructing a denitrifying bioreactor.
“The ground is just too dry,” says Couperus. “We spoke with the director of Rural Water Systems, and he said this is the first year he has not seen [water] flow in the gully in the spring.”
project, we know that there isn’t a certain right answer.” That’s the way it’s likely to be for the rest of their lives.
“Our bioreactor is a large stretch of carbon material—which, in our case, is woodchips—that the water filters through,” says Couperus. Water flows through the bioreactor, where chemical and biological processes convert the nitrates into less harmful chemicals. Last fall the team worked with Rural Water Sysytems # 1 to build their bioreactor in a natural gully. They used sustainable resources and, according to DeLawyer, made sure to “not disrupt water flow that would naturally occur.” “If we had waited to build until this
At first, this seemed like a major problem: without water flow, the team could not collect as many samples from the bioreactor as they first anticipated. Photo submitted
They had planned to use the solar collectors on the science building roof to capture energy but found that type of collector didn’t reach the high temperatures they needed.
Mark Van Weelden, Nathanael Couperus, Steven DeLawyer, and Luke Reznecheck designed and built a bioreactor for Hospers, Iowa.