Friday, February 22, 2013

Off Peak Cooling in Colorado

As you study the costs of electricity generation, you find out that Xcel's cost go up sharply during hot summer afternoons.  Back in the days of off-peak, or TOU, rates, PSCO tried to pass the extra cost on to the customers.  This pricing scenario has faded out over the years, but may come back.

Evaporative cooling works best at night, so you can accomplish off peak cooling by overcooling your house at night  and in the morning.  The cheaper coolers hardly work with a daytime temperature above 86F anyway.  The thermal mass of your house will then let you coast through the afternoon without using air conditioning at expensive rates.

Wednesday, February 20, 2013

Green Backup Power

After Hurricane Sandy, having a backup source of power for your home has become more important to some people.  Using a gas generator is one option, and they are very economical to buy, but not necessarily to run.  After Sandy, it was tough to find gasoline.  Another option is to have a permanently installed natural gas generator, but this isn't a good option in an all-electric home.

If a lengthy power outage ever hits Denver, those of us with large PV systems will be kicking ourselves for not installing an easy way to go off grid.  You see, all the PV systems you see on private houses currently DO NOT WORK if the grid is down.  The average refrigerator has $200-$300 worth of food in it.   I'm allergic to most candles, and they are a great way to burn your house down, so backup electricity would be nice.

I'm sure that the big power purchase agreement providers, SunRun and Solar City, are working on this, and I'll post the answer here when I get it.

EDIT 3/18/13:  The inverter company, SMA, will be releasing a new inverter that has this functionality.  It will have "an emergency power supply to provide daytime power in case of a grid outage".
This is expected in 2013, so be sure to request it for your house.
The ultimate system will use your electric vehicle or plug in hybrid for electrical storage and backup power.
R. Carter Scott plans to do this, and I'm sure he'll report more about it.

Wednesday, February 13, 2013

LED Lighting Innovation?

110v LED light bulbs each contain some circuitry to make them work with 110 volts AC.
LEDs are happier with 24VDC.  LED bulbs also use just a small fraction of the power of incandescent bulbs. That means that the typical 14 gauge wire going to light fixtures will be overkill for LED lighting, and be a big waste of copper.

So, theoretically, lots of money could be saved in new construction if the lighting power and distribution system could be optimized for LEDs. proposes to do just that.  This is a great idea, but boy, high volume means everything to low prices.  Trying to change how new homes are wired will be an epic uphill battle against code officials, old building professionals, and timid homebuyers.