New TV!

OK, sometimes saving energy can just be awesome.  

My old apartment was very small, and my couch was therefore only ~6 feet from my TV.  So my 32" LCD worked just fine.  My new living room is pretty large, and a 32" TV is just too small for me.  

I'd been looking around for a new LED backlit TV, but wanted the prices to come down a bit.  I got an early "Black Friday" deal on a 46" Samsung LED LCD, and it looks great.  It's a brand new model that came out the day I bought it.

This new TV has just over double the area of my old TV, so one would naively expect that it would take twice as much power to light it.  But LEDs are very efficient, so I had hoped that the power use wouldn't be any higher.  I did a test, with the exact same picture and similar brightness levels.  The new TV actually uses about 25% less power than my previous TV! (75W vs. 100W).  Awesome.  In addition, the vampire power is essentially non-existant (0.07W) and it has additional features that can decrease power consumption even further without affecting the picture much (which I'll use when I'm not watching sports).

Check out the Energy Guide sticker that came with it.  The estimated energy costs per year is so low ($12) that it's off the range in the sticker ($18-$51).  Awesome.

Energy Down the Drain, Literally

In a previous post, I patted myself on the back for replacing my shower head and saving 34% on my water usage during showers.  As an aside, I said that it was a "bonus" that I was also saving energy too, because I burned less natural gas to heat less water.

Well, I've been thinking about this - Is the energy savings just a nice little bonus, or is it actually a huge benefit?  Here are the numbers, if you're interested:

I don't know the exact temperature of the water being put into the water heater, or the temperature of my shower, but I've estimated 60 F and 105 F, respectively.  That 45 F degree difference is exactly a 25 Kelvin difference.  To raise the temperature of 1 gallon of water by 25 K takes about 400,000 Joules (heat capacity of water near room temperature: 4.2 J/(g-K)).

That means taking a shower uses energy at a rate of 13,000 joules/second, or 13,000 watts.  That is huge!  My shower is consuming energy at a faster rate than my whole-house air conditioning unit (see previous post)!

Granted, it's only for 10 minutes, but still.  Let's put it in terms of total energy.  I'm probably using about 6 kwh/day in electricity at this time of the year.  A ten minute shower uses 2 kwh, meaning my shower is 1/4 of all of my energy use in my house.  jeeez.  So in that respect, using 34% less water is HUGE, a savings of over 8% on my total energy use in my house, just by using a more efficient shower head.  awesome.

Note 1:  This is probably a lower limit on the amount of energy used because the water loses some energy as it sits in the tank, waiting for me to use it.  Thus, it needs some reheating.

Note 2:  All of these units of energy are interesting, but the energy to carbon dioxide conversion is not the same for electrical generation (via burning coal) and heating (via natural gas).  But that's for another post...