1. No category

Power in Transportation and Housing
To this point in the class, I've talked about electrical science
Which led directly into discussion of electrical power production
Neither subject is something known well by the "man in the street"
So I focused on clear explanations of what I thought was most important
To that end, I kept referring back to the "average US Power Plant"
Which I hoped could provide perspective and prioritization
For, while we shouldn't expect a new technology to compare favorably,
It should be making inroads by the time it is one or two dozen years old
Today we are turning from energy production to energy consumption
Which brings us to personal choices, and personal purchases
Taking us from information vacuum to information overload
Because, on the topic of consumer products, everyone has something to say
Ranging from almost every energy and environmental advocate
To almost every single marketing department or advertisement
And in this richness, I find that even engineers can also loose the big picture
By immediately jumping into the details of the various technologies
Thus, instead, I will continue to emphasize big picture principles and facts
At least to the extent that we can pin them down from basic science
THIS is the approach taken by the superb "Sustainable Energy without the Hot Air"
Which I will thus draw on for this lecture on Transportation & Housing
However, let's START by making sure we know what is MOST IMPORTANT:
Power in Transportation and Housing
Should these topics really be at the TOP of our energy consumption priority list?
Only if
1) They are among our heaviest areas of consumption AND/OR
2) They are areas where it might be easiest to reduce consumption
Transportation: Yes on #1
EIA: Arrows on the right
(in antiquated BTU units)
= U.S. energy consumption:
Source: EIA 2014 http://www.eia.gov/todayinenergy/
detail.cfm?id=16511&src=Total-b1
Housing: Yes on #2
Converting to easier to compare pie chart:
Exports (fuels):
10.8%
Commerce:
16.5%
Residential:
19.3%
Transportation:
24.7%
Residential + Transportation = 44%
Industrial:
28.8%
Big Surprise! / Big Deal!
Industry + Commerce = 45%
No big surprise
But is that really about me (personally)?
The 19.3% residential figure is certainly all about your personal choices
And as for how the 24.7% transportation figure breaks down
Plotted from 2009 EIA data:
Whoops!
59.7% = "Light Vehicle"
= You and Me (directly!)
Plus 7.7% Air
Probably still pretty much us directly
Plus 22.1% Truck
Us directly/indirectly
http://news.thomasnet.com/IMT/2012/03/12/the-damage-done-gas-addiction-edition-how-detrimental-is-petrol/
Part I: Energy in Transportation
For above transportation data, we SHOULD pro-rate by "per-ton" or "person-mile"
But even without that correction, the message is crystal clear:
Don't focus on buses or trains - They are doing just fine!
Shipping (despite those turbulent wakes), looks pretty damned good
So we can't just shove it off on importing too much from China
And I don't know what can be done to improve pipelines
As turbulence and oil/fuel viscosity are hard to beat
And vehicular transport alternatives (below) are hugely worse
Leaving us with the inescapable baddies: Cars, Trucks and Planes
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
So how could you improve the efficiency of automobiles?
City driving (stop and go)
Here power goes mostly into the car's own kinetic energy
Which is SPENT on every acceleration, then LOST on every braking
Approximate the car's city driving (stop and go) as:
Driving a distance d, at velocity vcity, stopping, then all of this repeating
Ignoring lesser energy losses to air resistance and rolling friction
In each of those intervals, fuel energy goes into kinetic energy of:
Ekcar_kinetic = ½ Mcar vcity
2
It spends that much energy (getting going) once every time interval = d / vcity
So average power (energy/time) = Pcity = Mcar vcity 3 / 2 d
So how do you increase car's city driving efficiency?
Answers are going to come right out of:
Pcity = Mcar vcity 3 / 2 d
1) Slow down (reduce vcity)
2) Find similar route with fewer stop signs / stop lights (increase d)
3) Decrease car's weight:
Buy a smaller car ("But that's downright un-American!!")
AND/OR buy a car built using lighter materials
Electric car's heavy batteries are going to be a problem!
4) Don't throw kinetic energy away (into heat) every time you stop!
That is, rather than heating brake discs/shoes, RECAPTURE that energy
Which CAN be done if car is powered via electric motor => generator
Called "Regenerative Braking" ~ 50% efficient = Potentially BIG deal
So for City Driving: BIG POSSIBLE WIN is via switch to electric cars!
CASE 2) Highway driving:
The interval between accelerations is now vastly stretched out
Diluting the (acceleration) kinetic energy expenditures of CASE 1
Dominant energy loss then becomes the loss to air friction (a.k.a. "drag")
That is, passage of car accelerates a volume of air up to almost the car's speed:
=> Transferring kinetic energy to individual air molecules
Volume then gradually slows and expands, as Ekinetic of 1st air molecules
is then shared with vastly larger number of air molecules
Car image from: www.clipartlord.com/category/transportation-clip-art/
Energy loss to drag can be modeled as follows:
Consider cylinder of air dragged immediately behind car
It will attain almost the car's velocity
But its cross-section will depend on car's streamlining
Better streamlining, less air accelerated => smaller cross-section (A):
Aair = cdrag Acar That is, it will be car's frontal cross-section x cdrag
With cdrag likely being < 1 and decreasing with streamlining
Behind car, in time t, will be accelerated air volume = Aair (vcar t). Moving at ~ vcar
Then, for air of density rair, can calculate that air's gained kinetic energy
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Kinetic energy gained by car's trailing cylinder of air:
Eair_kinetic = Edrag = ½ Mair vair 2 = ½ rair (volume of air) vair2 which becomes
= ½ rair (Aair vcar t ) vair2
=
½ rair (cdrag Acar vcar t ) vair3
Power = Energy / time = above / t: Pdrag = ½ rair cdrag Acar vair3
So how do you increase car's highway efficiency?
1) Slow down
2) Streamline more
Can't change shapes much more (and retain passengers / cargo)
So this mainly means smaller cars (with smaller cross-sections)
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Data on possibility of reducing car's drag:
After "Sustainable Energy without the Hot Air" (page 257):
Drag Coefficients (cdrag):
Honda Insight
0.25
Prius
0.26
Renault 25
0.28
Honda Civic
0.31
Volkswagen Polo
Drag Area (cdrag Acar) in m2:
Honda Insight
0.47
Volkswagen Polo
0.65
Honda Civic
0.68
0.32
"Typical Car"
0.8
Peugeot 206
0.33
Volvo 740
0.81
Ford Siesta
0.34
Land Rover Discovery
1.6
Audi TT
0.35
Honda Civic
0.36
Citroen 2CV
0.51
SIZE matters A LOT
SHAPE matters a little
Other alternative is, of course, to make engine more efficient:
And, despite decades of foot dragging, gas engines have improved (a whole lot!)
Fine print is also really interesting
SUV mania?
Source: www.epa.gov/otaq/fetrends.htm YELLOW arrows and comment added
"Ahhh . . . this must be due to the Prius and other new hybrid cars!"
NO!
The above (continuing) improvements predate hybrid cars:
For which (according to many experts) fuel savings are grossly exaggerated
Improvement is mostly just due to better internal combustion engines
Which had such low efficiencies that improvements were readily achieved!
Helped along by computer-aided design / computer-controlled ignition systems
AND by computerized transmissions better able to balance efficiency vs. torque
Including transmissions with "continuously
variable" motor to wheel speed ratios
(Continuously Variable Transmissions – CVTs):
http://nissanaltimaaustin.com/altimas-cvt-keeps-moving/
With intent of having engine spend more time near its most efficient speed
Same applies to Trucks - So let's move on to airplanes:
Does air travel being such a "bad actor" somewhat surprise YOU?
After all, how many trips do we (or "average U.S. citizens") take per year?
One, a few, a half dozen? (even including business travelers?)
Or could all of our Amazon.com airfreight deliveries have really hurt that much?
I made a half-hearted (but unsuccessful) try at answering both questions
But I'm pretty sure that real answer is that Flight uses LOTs of fuel!
(Which will come back to haunt us in the Carbon Footprint lecture)
So let's again follow Sustainable Energy Without the Hot Air's lead
and now learn a bit more about the energetics of flight:
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
First, to offset gravity, airplanes REALLY want to have lift:
To offset force of gravity, exploiting Newton's "Action = Reaction"
An airplane MUST steadily push LARGE volume of air downward (caused by
wings)
Omitting details (such as wingtip vortices) and approximating as a simple cylinder:
Masscylinder = density x volume = ρair x (vplane t Arealift_cylinder)
Where ρ is air density, A is cylinder's cross-sectional area
And (vplane t ) is the distance the plane flies in a time t
Jet image from: www.clipartlord.com/category/transportation-clip-art/
(continuing)
If, due to plane's passage, that air is forced downward at a velocity uair:
Cylinder's downward momentum = Mair uair = ρair vplane Alift uair t
Downward force = D Momentum per time which is then:
Forceair = ρair vplane Alift uair
Which must be in balance with the force of gravity = Mplane g
Equating and solving for uair = Mplane g / (ρair vplane Alift)
Use this to calculate the kinetic energy lost to that now downward moving air:
½ Mair uair2 = ½ (ρair vplane t Areacylinder)(Mplane g / (ρair vplane Alift))2
= t (Mplane g)2 / (2 ρair vplane Alift)
So power (energy/time) in that lift air is Plift = (Mplane g)2 / (2 ρair vplane Alift)
But in addition to energy expended on lift is energy to drag:
For which the analysis is just like that for the earlier highway driving car
And which (after updating the subscripts) gives us:
Pdrag = ½ ρair cdrag Aplane vplane3
Combining (and color coding) both LIFT and DRAG power expenditures:
Ptotal = Plift + Pdrag = (Mplane g)2 / 2 ρair vplane Alift + ½ cdrag ρair Aplane vplane3
With: Alift: Circle ~ size of plane's wingspan, Aplane: Circle ~ size of fuselage Xsec
Converting power per time to energy per distance:
Energy / distance = (Energy / time) (time / distance) = Power / velocity =>
Eper_distance = (Mplane g)2 / 2 ρair vplane2 Alift + ½ cdrag ρair Aplane vplane3
(To figure out fuel used, also need to include jet engine's efficiency e)
To minimize this (absolutely essential for airline's economic survival!) must have:
d/dvplane (Energy / distance) => 0
After some math (which I did, to check the book) you find that:
ρair vplane_optimum2 = Mplane g / (cdrag Aplane Alift)1/2
Left side = Things WE can tweak: speed and altitude (which affects air density)
Right side = Fixed things + plane's decreasing weight as it burns off fuel
Which brings us to some surprising conclusions:
From optimization:
ρair vplane_optimum2 = Mplane g / (cdrag Aplane Alift)1/2
Conclude (unlike cars) that for planes going slower is NOT better
In fact, if go higher (into thinner air) plane should speed up!
If this optimum speed condition is substituted into energy consumption equation:
Eper_distance = (Mplane g)2 / 2 ρair vplane2 Alift + ½ cdrag ρair Aplane vplane3
Find that, at optimum speed, first (lift) and second (drag) term are equal, thus:
At most efficient speed, plane spends ½ its power on lift, ½ on drag
With the total energy spent per distance then becoming:
Eper_distance_at optimum_speed = (cdrag Aplane / Alift)1/2 x Mplane g
Working from that final optimized equation:
Eper_distance_at optimum_speed = (cdrag Aplane / Alift)1/2 x Mplane g
Plane's ENERGY EFFICIENCY is not improved by:
- Making plane bigger or smaller: Changes in A's cancel, negating effect
- Changing altitude: Because air density has dropped out!
(But at higher altitude can go faster for same energy per mile)
Plane's ENERGY EFFICIENCY is improved by:
- Decreasing drag coefficient by making plane more "streamlined"
Limited by need to retain space for paying passengers / cargo!
- Making the plane lighter, which could be done three ways
By building it with lighter structural materials OR
Or hauling less/fewer passengers, cargo, bags OR lighter fuel
Which is exactly what they are doing . . .
By making everything possible out of lightweight plastic composites
And discouraging (or charging for!) excess luggage
Short of ALSO charging passengers for their weight (which would reflect costs)
The only remaining "knob to turn" would seem to be the fuel weight
But to travel the same passenger/cargo demanded distance, can't just cut fuel
Would instead have to get more energy per kilogram out of fuel
Leading us to this table and its rather surprising entries:
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Energy density of fuels (and would-be fuels)
Energy / Mass (mostly from from Richard A. Muller's book "Physics for Future Presidents"):
Conventional Battery
=
0.001 x Gasoline's energy density
PC Battery
=
0.01 x Gasoline's energy density
TNT (0.65 Cal/gm)
=
1/15 x Gasoline's energy density
Butyl alcohol
=
0.9 x Gasoline's energy density
Kerosene
=
0.93 x Gasoline's energy density
Gas / Diesel
=
1 x Gasoline's energy density
Liquid Natural Gas
=
1.3 x Gasoline's energy density
Hydrogen
=
2.6 x Gasoline's energy density
(Uranium or Plutonium
=
106 x Gasoline's energy density)
Only significant improvements to kerosene/JP-4 are liquid or pressurized gases!
Which would THEN require much heavier tanks (!@#!!$#!)
So it is not going to be easy to make flight more efficient
But still: How did flight end up consuming ~ 1/3 of trucking OR ~ 1/10 of cars?
Well let's work out some simple fuel consumption numbers:
Say as "average American" I drive my car (mostly alone) 12,000 miles per year:
Which (at least if its a new car) is supposed to get ~ 24 miles /gal*
I would then personally consume 508 gallons of gasoline per year
Say, in a plane, I also took one cross-country flight per year (not alone!)
JFK to LAX to JFK = 2 x 2775 miles = 5550 miles = 8880 km
With "Hot Air's" 747 plane number of 25 passenger-km / liter of fuel =>
355 liters ~ 80 gal which is already OVER 1/10 of my car's consumption!
NOTE HOWEVER PER KM:
Car ~ 9.4 km/liter
Plane ~ 25 km / liter
*Source: EPA automobile fuel economy chart from several slides ago
What about the other modes of transportation?
I dismissed ships, busses and trains because of small overall contribution
But, shouldn't we still try to make them more efficient? Yes, of course!
For instance, most all of the above suggestions for cars will also apply to busses
But trains are going to be hard to improve, because:
As one long body they are already well streamlined (Pdrag = small)
And, they already minimize starting and stopping (Pkinetic = small)
And with steel wheels on steel tracks, running friction is small
And finally, they already avoid going up and down hills
And surprisingly (at least to me) slow cargo ships are almost as efficient
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Yielding energy per freight load mass per distance transported:
After figure in "Sustainable Energy without the Hot air" page 92
Energy (kW-h / tonne / km)
1.5
1.0
0.5
0
Speed (km / h)
25
50
75
900
Images from: www.clipartlord.com/category/transportation-clip-art/ and https://lionelllc.wordpress.com/page/2/
Or energy per passenger per distance transported:
After figure in "Sustainable Energy without the Hot air" page 128
Energy (kW-h / 100 passengers / km)
150
Cars (gas vs. electric): Single passenger
Plane/Ship: Full-ish passenger load
75
50
25
0
Speed (km / h)
50
100
150
200
900
Images from: www.clipartlord.com/category/transportation-clip-art/
So to control transportation energy spending, priorities should be:
Cars and Trucks (assuming we will resist buying smaller and/or slowing down):
Streamline (where possible) or at least reduce forward cross-section
Go electric
Where engine efficiencies are higher AND
Regenerative braking recoups much spent power
"That's great because electric cars ALSO have zero greenhouse gas emissions!"
Energy saving: YES
Carbon free: NO!
Their batteries are charged by power plants, many of which are coal/gas fired
So they are responsible for (possibly even comparable) carbon emissions
And through their use of exotic, distantly mined materials, might even be worse
More on this in the upcoming Global Warming / Carbon Footprint lecture
And to reduce energy spent on other types of transportation:
Airplanes:
BIGGEST IMPACT: Teleconferences! / Local Vacations! (i.e. fly less)
Short term (small gain): Trim plane's weight by few more percent
Medium term: Opportunity for otherwise questionable biofuels?
Long term: Better figure out lightweight tanks for compressed gasses!
Trains: Damned good as is but could certainly USE THESE MORE!
Ships: Sure, some gain from less cross-oceanic importing, however:
Impact on total energy spent still small compared to preceding
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Part II: Energy in Housing
From the U.S. Energy Information Agency (EIA):
http://energy.gov/energysaver/articles/estimating-appliance-and-home-electronic-energy-use
Old homes ~ 40% space heating / 17% water heating / 7% air cooling / 30% appliances
New homes ~ 30% space heating / 17% water heating / 10% air cooling / 35% appliances
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
And in that final (30-35%) "appliances" category:
Department of Energy1 power data (mostly) plus my estimates on usage:
Device
Power
Use/day
Energy/day
Microwave Oven
1 kW
1/3 h
0.3 kW-h/d
Coffee Maker
1 kW
½h
0.5 kW
Clothes Washer
0.4 kW
1h
0.21 kW-h/d
Oven
3 kW
½h
1.5 kW-h/d
Cooktop range
3.3 kW
½h
1.6 kW-h/d
Refrigerator
0.7 kW
24 h
1.75 kW-h/d
Dishwasher
2 kW
1h
2 kW-h/d
Clothes Dryer
4 kW
1h
4 kW-h/d
Air Conditioner
0.6 kW
12 h
7 kW-h/d
1) Source: http://energy.gov/energysaver/articles/estimating-appliance-and-home-electronic-energy-use
Did you pick out the recurring theme?
Home energy is OVERWHELMINGLY about HEAT (or its movement)!
Energy consumption of built-in units:
30-35% Space heating / 17% Water heating / 10% Air conditioning
Plus "consumer" appliance heating/cooling energy hogs of :
Clothes dryer / Dishwasher / Refrigerator / Cooktop / Oven / Light Bulbs
So if you want to save energy at home:
If it isn't hot or cold
OR
If it doesn't affect heat flow:
Worry about something else first!
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
This is confirmed (in spades) by my decades of home ownership!
So here I will illustrate via relevant significant personal experiences
Above, energy consumption was divided into "built-in" vs. consumer purchased
The latter ("consumer") we almost completely control
The former we often either overlook or don't understand enough to influence
Accepting builder's choices of furnace / AC / H2O heater / insulation
This, as I've learned on my present home, can be a costly mistake!
Let's start with the biggest "built-in" energy consumer: space heating
My home came with a gas furnace (which IS cheaper than electric heat)
Both use simple ("dumb"?) direct conversion of fuel energy into heat
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
HVAC (heating, ventilation and air conditioning) 101:
What if, instead, we use electrical energy to move heat energy around? How?
By expanding gases (cooling them) & compressing gases (heating them)
With the electric power used ONLY for pumping (of gases and air)
This is exactly how air conditioners have always worked:
Gas/high vapor pressure liquid (Freon => Non-chlorofluorocarbon)
Is pumped (electrically) through a long loop of copper piping
Restriction in OUTSIDE of house part of loop causes gas to compress
Gas, in compressing and liquefying, dumps HEAT to piping
Piping is then cooled, via electric fan forcing outside air
Liquefied/compressed gas is then piped into house, where pipe opens up
Gas expands => it cools => cools piping => cools house air
Air Conditioner  Heat Pump
We can do exactly the opposite TOO: Compress in-house / Expand outside
Which would then BRING HEAT FROM OUTSIDE AIR TO INSIDE
And it doesn't even require TWO loops running in opposite directions:
Can just run pumps in one loop BACKWARDS!
ASSUMING: Outside air is warm enough to expand/vaporize gas (quickly)
On the Eastern US seabord: Works from mid-Atlantic coast southward
But isn't it easier to just burn natural gas / propane or electrically heat wires?
Yes, but heat pumps can be hugely more efficient
In heat pump, electrical energy is used ONLY for the pumping
1 watt of pumping power => 3-4 watts of heat moved! 1,2
1) http://energy.gov/energysaver/articles/tips-heat-pumps
2) http://en.wikipedia.org/wiki/Heat_pump
And finessing things a bit further:
Here, in the foothills, removed from the (warmer) coast, there can be a problem
As in last winter's sustained sub-freezing weeks
Then heat pump DOES begin to starve for outside gas warming heat
As result it pumps longer and harder, upping pumping power used
Enter "Hybrid" Heat Pump which adds back in LNG / propane burner
HOWEVER, its controller measures outside temperature
And ONLY switches from heat pumping to burner when Toutside < ~ 5°C
Impact? 5 years ago I replaced builder's installed AC + furnace
With hybrid heat pump:
My heating and cooling costs dropped by more than 1/3
Other "little" changes that can yield BIG energy savings:
1) I was raised in coastal California (well dehumidified by offshore Alaska Current)
So, here in east, chose hybrid heat pump with extra dehumidification
Cost very little because requires only slight redesign of inside cooling coil
~ Just need to extend time air spends passing by cooled coil
Vs. old: Water flow out "condensate drain" ~ 3-5X higher on humid days
And we are comfortable at inside temperatures ~ 1-2°C warmer
2) Low-E glass: My builder DID choose double pane windows, but not "low E"
Low E = Added IR reflecting plastic film (partially metalized) = cheap!
I replaced one room's French door/window with identical Low-E model
The summer temperature of that westward facing room fell by 3-5°C!
Coming: Wholesale replacements JUST for those sheets of plastic (!@#!%)
Or even cheaper ways to achieve big saving:
3) "Euro" style front loading clothes washing machines:
Hold it! Earlier DOE data put these at only 400W, used for short periods
Yes, but they are followed by dryers consuming 4000W, for longer
To save water, new washers don't just drown clothes in volumes of rinse water
They add a little water, then spin like crazy to remove that water
As a result, clothes leave the washing machine MUCH less wet
Thus requiring ~½ the time in the energy hogging dryer!
4) Cheaper fix? $100-200 for extra layer of fiberglass attic insulation
According to experts, builders seldom if ever add enough
Simple - but possibly itchy – homeowner's job (but best done in winter)
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Something even cheaper?
5) Door striker plates and seals: A key to eliminating winter drafts
Yes, first invest in double pane, Low-E windows
The latches of which then PRESS them closed, cutting off drafts
But then you'll run into our incredibly poorly designed US door / door frames
Edges of which are supposed to be sealed by thin rubber edge gaskets
Which ONLY work if door is pressed into them just right (within ~2mm)
But our door/fames come without locksets and striker plates installed
So that we can make personalized doorknob styling decisions!
I've owned three homes and built ~ four dozen Habitat for Humanity homes:
It is essentially impossible to install striker plates with ~ 1mm accuracy!
Striker plates continued:
If you install striker plate ~ 2mm too far in: DOOR WON'T LATCH
If you install striker plate ~ 2mm too far out: GET 2mm GAP TO OUTSIDE AIR
Why not just fix mistakes? Need new screw holes which must be > ~4mm away
I did eventually find online ONE adjustable striker plate
That, in my already chewed up doorframes only sort of worked
REAL (but still cheap, e.g. $5 to $20) SOLUTIONS:
i) Factory installed latches / striker plates
ii) Alternate adjustable or pull-tight type latches
(as already used in Scandinavia and other parts of northern Europe)
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
The energy lesson taught to me by stink bugs:
I DID manage to get my mail order adjustable striker plates to sort of work
But, in a fairly new, fairly well built house, we were still plagued by winter drafts
Then I noticed a trail of stink bugs crawling in at a door's corner
On hands and knees I figured out HOW they were getting past the door's seal:
Proper (full) door seals:
My door seals:
To save the (miniscule) cost of
miter cutting the gasket corners
(i.e. picture framing)
They just cut pieces ~ 1" short
Leaving breezeways
(& bugways) at all four corners!
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
(continuing)
These were not cheap doors (and I've seen same on other not cheap doors)
My solution:
Spent time on web to identifying replacement gaskets, then
For $35 bought enough to REGASKET every one of my doors
But I measured carefully AND made 45° razor blade cuts of ends
Which took me about 1 hour for six doors
(Would have taken door manufacturers trivial time & money!)
RESULT: My previously drafty house is no longer drafty
=> Same winter comfort at 1-2°C cooler heating temperature
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Can it really be that easy to reduce home energy expenditures?
U.S. vs. California per capita energy consumption (source: UC Berkeley):
Much of savings has been attributed to fairly modest energy saving standards
http://berc.berkeley.edu/californias-classic-chart-really-caused-energy-savings/
I suggest standards for "built-in" home energy units ARE desirable
For SAME reason building codes specify fire, plumbing . . . items:
We as consumers seldom know enough to make these decisions
Didn't parts of my long learning experience surprise you?
OR we lack enough leverage over builder's to ensure they choose well
Many builder's will ignore single purchaser's special requests
Others will lavishly overcharge for add-on energy features
So despite prevailing anti-big-government / don't tread-on-me sentiments
I strongly suggest that we should follow lead of states such as California
And incorporate more energy saving requirements into building codes
Result: MODEST increase in housing cost => LARGE/HUGE long term savings
On "consumer" side, information may be (almost) enough
That is, for the "consumer" appliances that WE choose:
Federal government already requires Energy Star labeling
Telling you how much $ you can save by perhaps spending a bit more
AND even with new homes builder's are required retain such labeling
So READ (and pay serious attention to) THE LABELS!
However, did YOU know washing machine choice could save big dryer expense?
This still came as a surprise to me!
Suggesting that more education, more labeling (more requirements?)
Should at least be considered even in don't-tread-on-me USA
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Because:
As in the earlier tale of our suddenly more efficient gasoline engines
U.S. housing, also influenced by cheap 20th century U.S. petroleum energy
Is still STUNNINGLY wasteful in its use of energy
Which is a problem that equals a HUGE OPPORTUNITY for improvement
Moreover, all of my experience tells me that a more energy efficient home:
Is NOT a too cold / too hot / too humid / otherwise uncomfortable
Instead an efficient home can be MORE comfortable AND cheaper to own
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm
Credits / Acknowledgements
Some materials used in this class were developed under a National Science Foundation "Research
Initiation Grant in Engineering Education" (RIGEE).
Other materials, including the "UVA Virtual Lab" science education website, were developed under even
earlier NSF "Course, Curriculum and Laboratory Improvement" (CCLI) and "Nanoscience Undergraduate
Education" (NUE) awards.
This set of notes was authored by John C. Bean who also created all figures not explicitly credited above.
Copyright John C. Bean (2014)
(However, permission is granted for use by individual instructors in non-profit academic institutions)
An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm