Biofuel Production From Municipal Wastewater

biofuel_wastewater

Reference: CleanTechnica

Researchers from Rice University are studying the potential for biofuel production using wastewater from wastewater treatment plants. They have shown that biodiesel-producing algae can thrive in municipal wastewater. This algae feeds on the organic matter in the wastewater and produces biodiesel as a byproduct.

In addition to producing biodiesel, the algae is also able to partially treat (i.e. clean) the wastewater. Researchers found that the algae removed 91% of nitrate-N and 53% of phosphorus from the wastewater. This is a win-win situation.

The applicable standard from the NGSS is:

HS-ETS1-3 (high school). Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics, as well as possible social, cultural, and environmental impacts.

Discuss this method of biodiesel production with respect to the standard.

Posted in Biomass Energy, NGSS High School Engineering | 1 Comment

Flywheel Energy Storage

Check out this video describing flywheel energy storage technology created by NASA.

The applicable standard from the NGSS is:

HS-ETS1-3 (high school). Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics, as well as possible social, cultural, and environmental impacts.

Discuss flywheel energy storage with respect to the standard.

From watching the video, what are the two ways in which energy loss due to friction is eliminated in flywheel energy storage?

The two ways are:

1) Using magnetic levitation to “float” the flywheel as it spins, rather than using bearings as support, which – although they are made to have as little friction as possible – still have a bit of friction and are still a source of energy loss as a result.

2) Spinning the flywheel in a vacuum in order to eliminate air friction which slows the flywheel down and is a source of energy loss.

Why is the flywheel shown in the video shaped like a ring?

Because for an object of a given mass, the highest rotational inertia is achieved when it is shaped like a ring. The basic physics here is that an object has more rotational inertia the farther its mass is located from the center of rotation. And the higher the rotational inertia an object has, the more kinetic energy it can store for a given rotation speed. This is desireable when designing flywheel energy storage systems for maximum efficiency, since you want maximum energy storage capacity for a given mass of flywheel. To learn more about flywheel physics click here.

Posted in Energy Storage, NGSS High School Engineering | 1 Comment

Solar Shingles

solar_shingles

Reference: Integrated Solar Technology

The company Integrated Solar Technology has developed electricity generating photovoltaic solar panels which also serve the same function as roofing shingles. Just like shingles, they protect roofs from the elements, and have an aesthetic appeal which many homeowners may prefer over typical rooftop solar installations in which panels are placed on framework that is placed on top of roofs. This system has the disadvantage of potentially requiring more effort to re-shingle a roof. In some cases, the solar panels may have to be completely dismantled from the roof to allow the shingles to be replaced. But with the solar shingles this problem is avoided since they comprise the actual roof covering.

The applicable standard from the NGSS is:

HS-ETS1-3 (high school). Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics, as well as possible social, cultural, and environmental impacts.

Discuss the solar shingles with respect to the standard.

In terms of safety, do you think a roof covered with solar shingles (as shown) is more or less safe to walk on than a roof covered with regular shingles?

Judging by their appearance, it looks like the smooth appearance of the solar shingles could also mean they are slippery to walk on, especially when the roof is wet during, or after, a rainfall.

If the glass surface of the solar shingles is made rougher so that slipping on them is less likely, this will probably block some of the sunlight from passing through the glass surface (and reaching the photovoltaic material underneath) which will mean that less electricity is produced by the solar shingles. This is known as a “trade-off” which is common in engineering design.

Read this link describing the product features of the solar shingles, and discuss which descriptions are more likely to be fact-based and which ones are more marketing-based (in which performance and function is exaggerated).

Posted in NGSS High School Engineering, Solar Energy | Leave a comment