Climate & Calculating BTU’s in Environmental Science By Dr. Rick Woodward
Atmosphere 1. The gas that is responsible for trapping most of the heat in the lower atmosphere is a. Water vapor b. ozone c. carbon dioxide d. oxygen e. nitrogen
Correct Answer a. Water Vapor
Monsoons 2. Characteristics or requirements of a monsoon include all of the following EXCEPT a. A seasonal reversal of wind patterns. b. Large land areas cut off from continental air masses by mountain ranges and surrounded by large bodies of water. c. Different heating and cooling rates between the ocean and the continent. d. Extremely heavy rainfall. e. Heating and cooling rates between the oceans and the continents are equivalent.
Correct Answer e. Monsoons are caused by winds from the southwest or south that bring heavy rainfall to southern Asia in the summer. -They are created by temperature gradients that exist between ocean and land surfaces.
Albedo 3. The surface with the lowest albedo would be a. Snow b. Ocean c. Forest d. Desert e. Black topsoil
Correct Answer e. Albedo is a measure of reflection of sunlight from a surface. Dark objects absorb energy, light surfaces reflect sunlight. -Dark topsoil would absorb the most energy and, therefore, would reflect the least resulting in the lowest albedo.
Jet Streams 4. Jet streams travel primarily a. North to South b. South to North c. East to West d. West to East e. In many directions depending on a multitude of factors
Correct Answer d. Jet streams are large-scale upper air flows that travel from west to east. -They are located between 3 ½ an 7 ½ miles above the Earth’s surface.
Jet Stream A. The jet stream is a current of fast moving air found in the upper levels of the atmosphere.
Low Pressure vs. High Pressure Air Masses 5. A low-pressure air mass is generally associated with a. Hot, humid weather b. Fair weather c. Tornadoes d. Cloudy or stormy weather e. Hurricanes
Correct Answer d. Cloudy or stormy weather
BTU’s = British Thermal Units A fundamental unit of energy in the English system. B. The amount of heat required to raise the temperature of 1 pound of water 1 degree Fahrenheit. 1 gallon of water = 8 pounds -Problems involving calculations: 1. They give you assumptions 2. They give you extra information that may not be used. 3. Always show your work 4. No Calculators
BTU Some Fun BTU Facts: 1. Gas-fired electrical power plant. 2. 15,000,000 kW-h of electricity every 24 hours (1 day) 3. Plant requires 13,000 BTUs of heat to produce 1 kW-h of electricity 4. 1 ft3 of natural gas supplies 1000 BTUs of heat energy
Calculation of BTUs 1. Calculate BTUs of heat needed to generate electricity produced in 24 hours. (1) Start with an equal sign = (2) Next write down the units you want to be in = BTUs (3) Next, what did you have to start with? The answer to this question is 24 hours 24 hours = BTUs 1
Calculation of BTUs (4) Next, what do you know about hours so that you can cancel the term? The answer is that 15,000,000 kW-h are produced every 24 hours. 24 hours x 1.5 X 107 kW-h = BTUs 1 24 hours
Calculation of BTUs Note: We are now in kW-h and we have to end up in BTUs. Was there any information regarding kW-h and BTUs? The answer is yes. 13,000 BTUs are required for every 1 kW-h. 24 hours x 1.5 x 107 kW-h x 13,000 BTUs = 1 24 hours 1 kW-h
Calculation of BTUs Correct Answer = 2.0 x 1011 BTUs per day
Next Question Calculate the number of cubic feet of natural gas consumed by the power plant each hour. Calculation Set Up 2.0 x 1011 BTUs x 1 ft3 x 1 day = 1 day 1,000 BTUs 24 hours
Correct Answer = 8.3 x 106ft3 natural gas per hour
Water Heater Question worth 6 points 1. They give you assumptions 2. Other information. 3. There may be information that you do not need to use. 4. Always label your parts/components of question in essay. 5. You don’t have to answer the questions in order. Water heater 50 degrees Fahrenheit. Assume water heater is 100% efficient. Use 40 gallons of water per day. Heat water up to 140 degree One gallon of water = 8 pounds No calculators can be used on test. What is a BTU: British Thermal Unit Defined: The energy needed to raise one gallon of water by one degree Fahrenheit. One Kilowatt hour = 3400 BTU
Question A • Calculate the yearly energy (in BTU’s) used to heat the water. (you get three points just for setup) -change gallons to pounds first. 40 gal 8 pounds 90 degrees F BTU__ 365 days___ = BTU’s Day gallon 1 pound F year Year (40 gallons)(8 pounds) = 320 pounds of water (320 pounds) (90 degrees F) = 28,800 365 days x 28,800 = 10,512,000 BTU/Year
Question B • Add an insulation pad to the water heater and save 5% of the energy. 10,512,000 BTUs/ gal 1,051,200 = 10% 2/1,051,200 = 525,600 BTUs/year
Question C • Discuss the economic and environmental cost of replacing your water heater. (0rganizational tool: Make this grid/chart for these types of questions) Economic CostEnvironmental Cost 1. Purchase cost 1. Throwing old one away 2. Labor to install 2. Landfill space 3. Packaging, etc. BenefitBenefit 1. Save money on energy cost 1. more efficient/less energy used 2. Less maintenance cost 2. Recycle old metal (works for dishwasher and washing machine, a-c, etc.) Now take this information and write about it. (Use Complete sentences)
Question D • List 2 ways to save energy. (write your responses in the form of a paragraph.) 1. Lower the thermostat. 2. Taking shorter showers (Don’t list more than 2 ways): Graders only look at your first two responses.
E. Convert to Kilowatt hours • Convert to kilowatt hours 10,512,000 BTU’s 10,512,000 BTUs 1 Kwh = Kwh 3400 BTUs 34/105,120 =
Question 1 (Growth Rate) • Rule of 70. 70/growth rate = the number of years it will take for the population to double • In 1999 U.S. Population 278 million World Population 6 billion Growth Rate U.S. 1% World 1.4% 70/r = # years for population to double
Growth Rate Question Continued a. In what year will the United States population double based on the growth rate? 1.4/70 = 50 (1999 + 70 = 2069) (1.4)(50) = 70 years b. In what year will the World’s population double based on the growth rate? (1999 + 50 = 2049)