Here in New England many home owners have their own source of wood they can use to heat their home. Or, they may decide that local wood or pellets can replace fossil fuels helping them achieve a level independence from foreign oil.
Working with a few of these customers, I have had the opportunity to put together combination wood and solar heating systems for both home heating and domestic hot water.
Green Living Journal published the story I wrote entitled “One Woman’s Journey to a Zero Energy Building”. I like how they advertised it on the cover (My Zero Net Energy Home) and put it out in Left Field
Click here if you would like to read it. I added some pictures in the blog post version. They didn’t have room for many pictures in the journal.
If you have been trying to keep up with what is happening in the world of solar photovoltaics (Solar PV or solar electric systems), you may have heard about microinverters, or small inverters.
In a traditional solar electric system the solar panel produces a DC (direct current) signal when the sun shines on it. Our homes are generally wired for AC (alternating current). The Inverter is the device that converts the DC signal to AC.
The simplest solar electric system consists of an array of solar panels all wired together and then wired to a central (fairly large) inverter which converts the DC to AC and “ties” that signal into your utility company’s grid connection.
Microinverters are small inverters that are attached to each solar panel, so that there is no need for a large inverter. Also, each solar panel acts independently so if one is shaded, the others are not affected. In a traditional system, the solar panels are wired together in series (typically 8-12) and if one module of that series gets shaded, the output from the whole series is reduced.
Solarfest is a fun weekend of renewable and sustainable living workshops both for adults and kids, highlighted by great music, food, and fun activities. All the electricity for the music stages, projectors in the workshop tents, lights, and vendor stalls is provided by solar photovoltaics and a wind turbine on site. There are also solar hot water showers for those who stay overnight (mostly in tents or RVs). Last weekend was Solarfest’s 18th year in production.
Two years ago I presented the goals, vision and planning for my business and home renovation, 78 Main St renovation, from a historic shell to a zero net-energy building (ZEB). At last year’s Solarfest I presented the completion of the project and some details on the data logging (Solarfest Workshop, 2011). In order to analyze the energy systems that were designed it is necessary to measure all the heating and electrical use of the house over the course of a year (or more).
It has been a very busy couple of weeks with a number of interesting solar installations … but I found a moment this weekend to do some catching up.
One install we have been working on is for the Hartford Emergency Services Building (Police and Fire) on the VA Cutoff road in White River Junction, VT. This project calls for 13kW solar array on its flat roof, which was recently resurfaced with a white membrane material. Since it was a new roof with a warranty, we had the roofing company do training, inspections and repairs for us in order for them to uphold the warranty.
Living with a solar energy system will raise your awareness of the sun’s presence to a new level. Now that I am living in a solar powered home (78 Main St renovation), I can provide way too much information on how many days the sun peaked out in December, how much of the energy of the sun still comes through on a cloudy day, and how powerful the sun is on a cold, but bright sunny day in February.
I have a good selection of monitoring and measuring devices for my solar systems, so I am able to determine exactly what are the “perfect” days for peak energy production. It might not be what you expect…
Foaming the storage tank
I can now fully appreciate the benefit and even the necessity of a backup heating system in New England. In 2011 alone there were 3 or 4 storms that caused power outages, but I have been very lucky that they only caused minutes or a few hours of interruptions for me. Many others experienced days without power. On the other hand my solar heating system is in its first year of life and needs some serious debugging, so my back up systems are needed – often!
In this part of the world multiple days without heat in the winter can be life threatening. This, and the potential for frozen pipes, provide ample reason why insurance companies want to know the details of a home’s heating system, and it’s backup, before providing insurance.
This week I wanted to post a few thoughts about data, data logging and how to get real information from streams of data. In my business I sell renewable energy systems to home-owners and I like to be able to show them exactly what they are getting from their investment. How much energy is this new system producing for them and how much oil, propane or electricity they are saving compared to previous years.
First of all raw data is generally streams of numbers that most people don’t really care about. It can be interesting to know right now, at this moment, how much electricity is my house using. But after that, raw data gets boring. It starts getting interesting again when we keep a log of data with the timestamp of when it was taken. Then, to turn this data into real information, we just need to graph the data over time and see how the electrical use varied over the course of a day, a week, a month or a year.
Solarfest was a lot of fun this year! I learn so much from the attendees and the other vendors. It is an important part of my renewable energy continuing education.
This year I learned about fixed magnet versus electromagnet motors (as used in wind or water turbines) and how to provide appropriate electrical circuits to support them. I learned a few more good uses for composting toilets and backyard garden composters based on what people are actually doing with these products. I got the answer to a question that one of my customer’s had about his grid-tied battery backup system that didn’t always sell all his solar power back to the grid. And I heard a few more interesting ways that people are making their own hot water batch heaters.
SHW Data Graph
I’ve been getting a little frustrated these days by the lack of good data for SHW (solar hot water) systems. It is expensive to add data logging to a system and it isn’t always clear if the data you get can give you actual information that you can use to make decisions and calculate your return on your investment (see an earlier blog: Data Logging – real information
In the Solar Electric, or PV (photovoltaic) world, it seems like every grid-tie inverter manufacturer wants to prove that their system works well, so they provide relatively easy ways to log data and show you the results in a graphical way.