Efficiency of a Water Heating System
What's the efficiency of a water heating system?Copyright NASA http://blogs.nasa.gov/cm/blog/ISS%20Science%20Blog/posts/post_1301433765536.html
Students use a watt meter to measure energy input into a hot plate or hot pot used to heat water. The theoretical amount of energy required to raise the water by the measure temperature change is calculated and compared to the electrical energy input to calculate efficiency.
Engineers strive to improve the energy efficiency of processes, since some energy is lost in each of the conversion processes. They have learned that more complicated processes that have many components are typically less efficient than simple systems. Making systems that include energy conversions more efficient can help to reduce our nation's consumption of fossil fuels and production of greenhouse gas emissions.
After this activity, students should be able to:
- Explain where energy is "lost" in conversions and why based on the second law of thermodynamics.
- Compute the efficiency of an energy conversion given input and output.
- Identify system by-products and explain how they can be used effectively to increase overall system efficiency.
- Use collected data to calculate the efficiency of a system.