Energy and Air Pollution Flashcards
(35 cards)
What are important greenhouse gases?
Carbon dioxide (CO2), methane (CH4), dinitrogen monoxide or nitrous oxide (N2O), CFC-11, HFC-23, carbon tetrafluoride or tetrafluoromethane or R-14 (CF4), ozone
Arguments in favor of climate change
Yes, cyclic warming and cooling occurred. But there is scientific, data-based evidence like carbon dioxide causing additional warming as well as glacier melting and mass extinction
What is the global radiation budget?
Refers to cycle of radiation earth receives from the sun as well as radiation produced by the earth and emitted by the atmosphere. In addition if what is already being absorbed from the sun, greenhouse gases cause back radiation that also heat the earth.
How many gigatons of carbon dioxide (CO2) have we emitted? How many are we omitting each year?
> 10, 1 per year
What does the IPCC report state?
A maximum of 1.5°C warming is allowable between now and 2050.
What is the significance of CO2 according to the IPCC?
Carbon dioxide (CO2) is a greenhouse gas. Greenhouse gases contribute to global warming because they easily trap heat/long wave radiation in the atmosphere and warm the planet. Since the industrial revolution and especially the second half of the twentieth century, humanity has been emitting record levels of CO2. It is estimated that we have emitted more than 10 gigatons of CO2 in total, and that we are currently emitting 1 gigaton of CO2 per year. Since greenhouse gases—like CO2—are warming the planet, global average temperatures are expected to increase greatly. An increase in global temperature can have devastating effects on the environment and those who occupy Earth. Glaciers will melt, sea levels will rise, and people will be displaced. The Intergovernmental Panel on Climate Change (IPCC) stresses that a global temperature increase of only 1.5° is allowable by 2050. They believe that in order to control global warming and keep the global temperature from increasing more than the allowable amount, we need to work together to reduce our CO2 emissions by 45%
How does heat loss in a building occur?
Through walls, ceilings, windows, doors, infiltration
What is a BTU?
British thermal unit. Defined as the amount of heat required to raise the temperature of 1 lb of water by 1°F
What is a degree-day?
Basically how hot or how cold it has been over a 24 hr period. Heating degree day (HDD) is number of degrees F below 65 F over time period. CDD is Huber of degrees F above 65 F.
What does adiabiatic mean?
No heat transfer
What does isochoric mean?
Constant volume
What does isobaric mean?
Constant pressure
What does isothermal mean?
Constant temperature
How much of the water in the US is used for cooling power plants with cooling towers?
Nearly half of withdrawn water, with a lot of that happening in Texas and California
How many gallons of water were used to produce 1 kWh of electricity?
19
How many kilowatt hours per person per month are used in the US?
1000
How is heat transfer driven?
Difference in enthalpies of bulk air and saturated air at water interface. A bigger difference means a larger heat transfer and thus cooler water and warmer air
What is the approach?
The difference between the cooling tower outlet cold water temperature and ambient wet bulb temperature
What is range?
The difference between the temperature of water entering the cooling tower and leaving the cooling tower
What is the significance of the l/g ratio?
L/g is the liquid gas ratio and is defined as the ratio of water flow rate to the air mass flow rate. The L/G ratio affects the effectiveness of the cooling tower
What are challenges in the cooling tower sector? And how are they being addressed?
1) water scarcity (recovery and reuse)
2) corrosion control (reduce bio fueling)
3) control scaling (treating water and removing silica, iron, clay)
4) energy efficiency (reduced biofueling and improved water quality enhances energy transfer)
How can ethanol be harvested as a biofuel?
Corn kernels (where energy is stored in the form of starches and sugars are stored) are milled and digested by enzymes from yeast.
Future of biofuels
14M hectares of farmland could be available for energy crops by 2030
What are the two air pollution categories?
A,being air pollution
Indoor air pollution (home, business, airplane)
