BIT Studio

May 9, 2016

Solar Office

Filed under: Solar — webmaster @ 11:10 pm

  The Armageddon-Lite Project was conceived after the December 2013 power failure in Toronto. We were without heat for three days in subzero weather and we decided that if we had had heat, life would have been (relatively) comfortable. Our furnace is a natural gas boiler-radiator system that requires 460 watts of electricity to drive the PLC, circulating pump, and exhaust fan. I put together specifications for a solar-driven battery backup system to run our furnace, freezer, iPhones and iPads in the case of a prolonged power failure.

Our current electrical backup system has five solar panels (500 watts), two 100Ah deep cycle 12 volt batteries, one 1000 watt pure sine wave AC inverter, one 1200 watt gas generator, and one 12 amp 120VAC-to-12VDC inverter. The panels typically generate 8 amps of power in medium sunlight, which means that in Canada (three or four hours of direct sunlight per day), the system can generate about 25 amp-hours of electricity per day. In emergencies, the system is capable of running the furnace on solar power through the daylight hours. At night, two or three hours of gas generator operation top-up the batteries sufficiently to run the furnace through the night.

The original non-emergency version of Armageddon-Lite operation was fairly simple. My intent was to power a mini-fridge (230 watts) and mini-freezer (240 watts) every day. While the off-grid system was adequate for powering the fridge and freezer in daylight hours, the 24/7 nature of the appliances required grid-powered battery charging for four hours per night to charge and maintain the battery level. Although operationally successful, it was a lot of work to monitor and sustain.

So… the current state of Armageddon-Lite, non-emergency mode, is powering my home office. I turn on the 1000 watt inverter in the morning and this powers my computer, three lights, a single-cup coffeemaker (yay!), and minor office peripherals throughout the day. Also, on most days I am able to plug my hot water tank into the system. The office and water heater draw less power than the solar panels provide and at the end of the day, the batteries are fully charged (i.e. over 13 volts) and ready for the next day’s use.

The Armageddon-Lite Project is an evolving work-in-progress. Our next step involves the addition of one more deep cycle battery to increase the capacity of evening storage. The new hardware will connect easily to the existing framework and provide sufficient capacity to run the home office, the mini-fridge, and the mini-freezer without requiring nighttime inverter-to-battery support from the grid.

It is not much, but it keeps us prepared for the next power outage and maintains a small portion of the house as officially “off-grid.” Fun stuff!


August 28, 2015

Armageddon Lite 1.0

Filed under: Solar — webmaster @ 9:51 am

  Our homegrown electricity backup system is working: six solar panels feed two 100Ah batteries that run a mini-fridge and mini-freezer. It may seem that Armageddon Lite 1.0 is about cold beer and ice, but it is really about heat.

It was the power blackout in Toronto during December 2013 that inspired this nerd adventure. Our natural gas boiler furnace needed 460 watts of electricity to operate and we had no power for three cold sub-zero days. The solar system produces approximately 8 amps of current on sunny days and is backed up by a 110V battery charger on days with grid power and a 110V gas generator on days without grid power. During cold-weather blackouts, the fridge and freezer are unplugged and the furnace is plugged in.

The system framework provides for easy expansion and Armageddon Lite 2.0 will likely include additional solar panels and batteries to reduce the dependency on the battery-charger backup system.


December 22, 2014

Armageddon Lite

Filed under: Solar — webmaster @ 9:53 pm

  Phase 1 of Armageddon Lite is complete!

This nerd adventure began as a result of being without electricity for three days in sub-zero weather during Christmas 2013 in Toronto. The other utilities (water and gas) survived and it was determined that if we had had power backup sufficient to run the furnace, we could have stayed in our house for quite a while.

The furnace, a natural gas boiler with rads, requires 460 watts to run a PLC, thermostat and two motors – one motor for the blower and another for the circulating pump. Running non-stop, the furnace would consume approximately 4 amps of electricity per hour (watts = amps x volts, that is, 460 = amps x 120). In very cold weather, the furnace might run for up to 30 minutes per hour, which would consume 2 amps of electricity per hour. The design of the backup system would, at the very least, need to be able to sustain this requirement.

Battery Backup System:
-2 batteries (12V DC, 100Ah, deep cycle, sealed)
-1 inverter (DC to AC, pure sine wave, 2500 watt)
-1 generator (gas powered, 1200 watt)
-1 battery charger (12 amp, AC to DC)
-1 55 watt solar array (3′ x 3′ panel, trickle charger)
-1 battery charge controller (DC to DC, 7 amp)

In the event of a power outage, the furnace is unplugged from the house outlet and plugged into the inverter. The 2500 watt inverter is larger than necessary, but in less extreme temperatures, it is very likely that other appliances (such as, a fridge, a water heater, cellphone chargers) could be plugged into the system. Based on a consumption of 2 amps per hour, the 200 Ah battery bank would drop less than 15% of capacity over a 12 hour period (24 amps / 200 Ah), which is well within battery operating specifications. Using this model, the gas generator could be run one hour in the morning and one hour in the evening to top up the battery charge. Assuming that natural gas (for the furnace) and gasoline (for the generator) are available, this infrastructure is sustainable for a very long time. The trickle charger keeps the batteries healthy during long periods of inactivity.

Phase 2 of Armageddon Lite involves installing and connecting a rooftop solar panel array to the existing system. Four 250 watt panels (1 Kw) would provide sufficient electricity to support a mini-fridge and mini-freezer throughout the year without generator support. As a green yet somewhat shallow solution for cold beer and ice, Phase 2 isn’t quite part of an armageddon scenario. It does, however, build upon an existing framework for expansion into an autonomous, off-grid solution.

June 20, 2014

Emergency Power

Filed under: Solar — webmaster @ 8:11 am

 Canadians can expect only 3 or 4 hours of usable solar power sunlight per day and a realistic expectation of what a solar system can actually accomplish is critical. An oversight in my previous calculations made my original plan unfeasible. I had not fully taken into account the overhead required to convert 12V DC power to 110V AC.  A 1000 watt DC to AC inverter requires approximately one amp per hour to operate, and in a closed solar system this creates an additional load expense of 24 amps per day. The inverter overhead, not including appliances, would require an additional 150 watts (watts=amps x volts, plus rainy day variables) of solar panels.

It was not unusual 10 years ago to pay $10/watt for an installed solar-to-grid system. For example, a 2 kilowatt rooftop solar system would have cost $20,000. The cost is much less now and solar panels for under $1/watt can be found. A system that includes a charge controller and inverter can be purchased for under $4/watt, and depending on the interface (batteries versus grid), a complete $5/watt system is possible.

The cost of a system to power a mini-fridge and mini-freezer (and emergency furnace power when needed) would be at least $2,500 plus installation plus rooftop real estate. In Ontario, we have the luxury of paying less that 20 cents per kilowatt hour for our electricity. If it was just about cold beer and ice cream, the return-on-investment would be well over 20 years, which is prohibitive even by European standards. But the purpose of the system is to have a back-up in place for a grid power failure, and for that the ROI figures become much more forgiving.

The solar component of this project has been reduced to a 150 watt trickle charger (1m x 1m solar array) that maintains two deep-cycle, sealed, 100Ah batteries. The day-to-day responsibility of the batteries has been reduced to lighting the laundry room with two 0.2 amp LED lights. In case of a power failure, running a 1200 watt gas powered generator for one hour per day provides sufficient battery energy to power a furnace and fridge throughout the day, as well as a hot water tank and freezer for one hour per day while the generator is running. For communication and entertainment, phones and iPads would be chargeable anytime.

The emergency power back-up system will cost less than half of the original project and depending on the duration and severity of the next blackout (and your skill with a sharpened pencil), the project ROI could be as little as three or four days. The system could be easily expanded in the future to include more solar panels as the battery infrastructure will already be in place.


February 10, 2014

Solar Panels

Filed under: Solar — webmaster @ 7:18 am

  The winter storm of 2013 in Toronto inspired some green(ish) off-grid thinking. We were without electricity for three days and although it was certainly an inconvenience, things could have been much worse. On day 3, just before the power came back on, the house temperature had dropped to 13 deg C (candles kept us going) and we were ready for a hotel. We decided that if we had had the basics of 1) heat, 2) food and 3) communication, we could have lasted a long time.

A hybrid solution of solar panels and batteries combined with a small back-up generator could accommodate our requirements. The system would need a sustainable infrastructure that would be always running and emergency-ready. For heat, the house has a natural gas furnace (radiator) that requires about 450 watts (3.5 amps) to power the exhaust fan, water pump and electronic ignition. For food, a small Danby fridge draws close to 200 watts (1.6 amps) and fondue pots (as we found out!) are incredibly efficient cooking devices. For communication, cell phones and tablets draw little electricity but still require a pure sine wave power source to charge safely.

-165 watt solar panel array
-2 battery charge controllers (DC to DC, 7 amp)
-2 batteries (12V DC, 100Ah, deep cycle, sealed)
-1 inverter (DC to AC, pure sine wave, 1000 watt)
-1 generator (gas powered, 1000 watt – for emergency only)
-1 battery charger (25 amp, AC to DC – for emergency only)

The system is designed around a 1000-watt power requirement. Small fridges and freezers consume approximately 250 Kwh per year (700 watts per day) and the above solar panel system should be able to sustain the daily operation of one mini-fridge and one mini-freezer throughout the year.

In the event of a power failure, the freezer would be unplugged from the system and the furnace would be plugged in. The additional power usage requirement (freezer at 200 watts versus furnace at 450 watts) would be met with a small 1000-watt gas-powered generator. Running the generator for one hour every evening would top up the batteries as required. The gas water heater and freezer could be plugged into the generator. The daily one-hour operation should provide sufficient energy 1) for hot/warm water throughout the day and 2) to maintain the freezer at an adequately low temperature for quite some time.

Once installed, the system should be very low maintenance. The batteries are sealed and under the proposed conditions should last for at least three years. The switchover from standard to emergency mode requires moving three plugs (furnace, freezer and water heater). Running the generator would be for emergencies only and with a bit of luck, it may never see any action.

And that is the idea. Now for the implementation…


August 21, 2010

Energy $$

Filed under: Solar — webmaster @ 3:38 pm

  My 2kW rooftop photo-voltaic power system was hooked up to the grid and commissioned in late March. Since then I have received three cheques from Toronto Hydro.

The cheque for April netted approximately $200, May $185 and June $175. Although this seems like an unlikely trend as summer progresses, there are many factors that could affect the sun’s exposure to the panels. June could have been more cloudy and rainy. Humidity and air pollution are also factors and this summer has been a muggy one.

I was hoping to achieve an average of $200/month through the year and this puts me a bit behind my target. Winter days are shorter and although the air is typically drier and cleaner, I anticipate winter revenue will be less. More to come.

March 28, 2010

We Have Ignition!

Filed under: Solar — webmaster @ 3:30 pm

  The 2kW solar panel array on my rooftop is now fully operational and sending power into the province’s power grid. How cool is that?

Ten 5′ x 3′ panels are wired into an inverter, which converts DC solar energy into 220VAC, and feed an export meter located on the outside wall of our house, adjacent to the import meter. The “series” system connects both meters directly to the 200 amp electrical panel in our basement. Thus far, the inverter indicates a variable range from zero (no direct sunshine) to 1780 watts (mid-afternoon), which I assume is OK for an early-spring day.

A bright, mid-afternoon, summertime sun should generate approximately $1.50/hour for two or three hours per day. My first job in 1972 was pushing carts at Loblaws and it, too, paid $1.50/hour for a few hours per day. Solar power production is certainly not a fountain of cash flow, and the ten-year-plus return on investment is hardly exciting. But it still beats pushing carts.


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