BBBrown.com
The solar generating system for our home consists of
22 Sanyo HIP200-BA3 200 watt photovolatiac modules,
2 Outback Power Systems GVFX-3648 inverters,
2 Outback Power Systems MX-60 charge controllers, and
8 Concorde PVX-2240T backup batteries. The roof mounted panels consist of two arrays. One 1.6 kw array faces south and the other 2.8 kw array faces west providing a total of 4.4 kw capacity. The batteries can power our emergency circuits for several hours insuring uninterrupted power to our lighting, computers, and refrigerators. For more details of the various components click
here.
The system has been in operation since November 19, 2007. We received the standard, $4 a watt rebate for the installation from the State of Florida under their solar incentive program. This amounted to a check for $17,600. Operational statistics are shown below including near realtime charts and data. More detailed information can be found by exploring the menu on the left.
2012 Data
Now collecting data on our system. The early months of the year are often very interesting. The provide worst case and best case situations.
Yesterday, January 3, 2012, is a perfect example. The day was great for generation. Our system generated around 20 kwh because of a clear day. So it was a very good situation for generation but it was also a very cold day. The nighttime temperature last night went down to 40 degrees. We had the radiant heat on all night long. in addition, our irrigation system came on since winter is our dry season. For our system the 24 hour usage was massive, 140 kwh. We normally use from 30 to 50 kwh a day at this time of the year.
Our hot water system has filled the 80 gallon water storage tank with extremely hot water. Many people think that in very cold weather hot water production will be low. If the day is clear then hot water production is very high regardless of the air temperature.
I intend to collect data periodically during the coming months to capture situations like this. For 2012 I do not plan to collect data every day.
Data Collection
We collect daily readings from our electric meter and from our Outback charge controllers. The meter provides total KWH used and sold back to the utility. The charge controllers provide total KWH generated as two numbers, one for each array. The data are entered into a Google Spreadsheet that calculates various parameters including percentage KWH generated from our photo-voltaic panels. Google Spreadsheets then provides various graphing capabilities that are used to generate the interactive charts for this page.
No Data Being Collected
We have stopped collecting daily data for a while. We have accumulated four years of daily data. This is sufficient for our purposes. If you are interested in seeing our systems performance live you can always visit
our live daily logger site. The logger uses software called
MySolarLog
We are entering one of the two peak production periods of the year. The key is clear skies and cool temperatures. Clear skies for optimal production and cool temps for minimal use of air conditioning. Of course, spring is the best because the temperatures are still cool, days are getting longer, and the skies are clear.
We must look into further automation of data collection for our system. At this time we still require a manual read of the meter each day to calculate percentage of total usage from the photovoltaic system and the grid. There has to be a better way.
Percent Generated Last Month
Longer days and clear skies are providing ideal conditions for our solar panels. We are generating higher amounts of electricity each day. On February 16h we generated 60 percent of our electricity from solar. The days have been warm but not hot. We have only run our air conditioning on a few days when the temperatures outside were in the mid 80s.
Percentage Energy Generated As Five Day Moving Average 2010
This is an interactive chart generated from a Google Spreadsheet showing production from our solar panels for the current year of operation as percentage of total electricity used. You can move your mouse cursor over the chart to show data for an individual day. Move the ends of the bottom chart in to magnify any part of the chart.
"Cash for Clunkers" appliance replacement and pool blanket.
June 15, 2010
A month or so ago the State of Florida had a "Cash for Clunkers" appliance replacement program. Much like the program the feds had for cars, Florida offered rebates for old energy hog appliances. We used the opportunity to replace our garage refrigerator which used 3.7 kwh per day. The new one uses 1 kwh per day measured with my Kill-A-Watt. The one appliance was all we could afford but with a net expenditure of around $300 a day we saved about 7 percent of our daily energy use. To offset this amount with additional photovoltaic panels would have cost nearly $2,000. So, you can see that conservation pays big dividends.
We have a solar pool heater. The pump and filtration system is used to pump water to our porch roof where a black collector heats the water and returns it to the pool. A thermostatically controlled valve closes that circuit when the pool reaches a preset temperature or when the water in the roof collector is cooler than the pool. Evaporation is a powerful cooling process. Remember the old "swamp cooler" air conditioners where water flows down a tower through which air is drawn? Well a swimming pool is very much the same in that the evaporation from the surface cools the water below very efficiently.
I had been running my pool pump for a few hours a day just to heat the pool and yet in the cooler months I could not get the pool above 74 degrees. So, I bought a pool blanket. It is kind of like a big sheet of bubble wrap. After putting it on the pool it took two days for the pool to climb to 83 degrees. My pool is a small one but it still holds 10,000 gallons. It takes a lot of energy to heat 10,000 gallons several degrees. The good news is that I was able to reduce my pool pump run time to a little over an hour and the system is maintaining the temperature at 80 degrees. I am saving quite a few kilowatt hours per day and my pool is now very inviting and warm.
Weather and NPR, July 16, 2009
Our weather has been unusually hot. High temps daily in the 90s. That is really unusual for us. Even so, our PV system has been cranking out 35 percent and up of our energy. With the AC running constantly that is not too bad. We still have a lot of work to do on conservation. When our major appliances get old enough we will replace them with Energy Star ones. We have two refrigerators and that alone should save us about 10+ KWH per day. It is more cost effective to replace inefficient appliances than it is to add more solar panels.
A couple of days ago while taking Barbara to the dentist I turned on the radio. It happened to be tuned to NPR and the Dian Rehm show. They were talking about solar energy. It was a good show with a great panel made up of:
Rob Lamkin, CEO, Cool Earth Solar
Rhone Resch, president and chief executive officer, Solar Energy Industries Association
Peter Fox-Penner, principal and chairman emeritus, The Brattle Group, an international economic consulting firm,former Department of Energy official, and author of the forthcoming Island Press book "Smart Power"
Alex Daue, Renewable Energy Coordinator with the Wilderness Society.
Something urged me to call in and boy was I shocked when they took my call. I was so surprised that my thoughts were not as organized as I would have liked them to be. I still managed to convey some of our experiences of living in a solar home and got a nice compliment from the panel. You can go to the Diane Rehm Show website and listen if you want. My call came in about two thirds of the way into the show. Click
here to go to the website. The audio links are on the right.
Created on 07/30/2009 04:09 PM by rbrown3rd
Updated on 01/04/2012 05:00 AM by rbrown3rd
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