Nathan Fuller 1/15/11

Alternative Energy Systems and Applications Solutions Manual Hodge

Chapter 1 1. What is a quad?

A quad is a measurement of energy usage. One quad is 10^15 Btu.

2. What is the difference between energy and power? Energy is measured in Btu or ft-lbf. Power is the rate of energy usage typically measured in kW. P=E*t

3. What was the total energy usage in the United States in 2007? 106.96 quad p.6

4. In 2007 in the United States, what percentage of coal production was used to generate electricity? 23.48/106.96*100 = 21.95%

5. How much renewable energy was used in the United States in 2007? What were the dominant sources of renewable energy? 6.8 quad or 6.4%. In order from highest to lowest percentage of renewable energy: Hydroelectric, Wood, Biofuel, Waste, Geothermal, Wind, Solar/PV

6. How much energy used in the US in 2007 was imported? 34.6 quad or 32.3%

7. What has happened to US energy imports since the 1970s? Since the energy crisis of 1970s US Imports has steadily increased.

8. What does EIA stand for? Energy Information Administration

9. In 2007, what percentages of US energy were used in residential, commercial, industrial, and transportation applications? Residential 21%, Commercial 18%, Industrial 32%, Transportation 29%

10. From 1980 to 1995, in terms of inflation-adjusted dollars, what happened to the prices of gasoline and electricity? In terms of real dollars the cost of both gasoline and electricity declined resulting in a period of little encouragement for more efficient and alternative energy sources.

11. What has happened to world energy usage since the 1970s? The United States increased slightly while Russia decreased slightly. However China’s demand increased significantly. The overall world demand is rapidly increasing.

12. What is the Carnot efficiency? What is its importance? The Carnot efficiency is the efficiency of any external reversible heat engine operating between high and low temperatures. η=(Th-Tl)/Th. This sets a bound for the maximum efficiency obtainable by any heat engine.

13. In comparison to most mechanical devices, how efficient is photosynthesis? Mechanical device efficiency ranges from 3 to 99% efficient with many systems in the middle of this range. Photosynthesis ranges from .5 to 5% efficient. Therefore photosynthesis is much less efficient than mechanical systems.