Technological Challenges of Off-Grid Homestead Living, Part 5: Heat


| 12/1/2015 11:35:00 AM


Tags: debt free living, small homes, off grid living, home heating, home energy, wood heat, Christopher James Marshall, Oregon,

Read Part 1, Resources, of this series here. Read Part 2, Electricity, here. Read Part 3, Water, here. Read Part 4, Food, here.

A happy home warms your heart and the sun warms your home, either way, heart or home, sometimes it can be too hot or too cold. In the Cascade Mountains, where I live, the outside temperature ranges from 100 degrees F in summer down to freezing in winter.

In any climate, the least expensive heat systems are the thermal features of the house itself designed to conserve heat and reduce fuel costs. My affordable small house has six inches of insulation in the walls (R19), ten inches in the ceiling (R30), all the pipes are insulated, the attic is ventilated, and the root cellar under the first floor is exposed to the earth. My shady front porch faces north and stays cool, while the attached greenhouse faces south and stays warm. There are operable vents on each wall of the two floors and a cook vent fan on the first floor and a ceiling fan in the second floor.

Heat energy is constantly flowing from hot to cold areas. Controlling heat flow by slowing it with insulation or increasing it with ventilation, collecting and releasing heat by storing solar energy, and/or burning fuels is how to manage heat for comfort.

Summer and Winter Modes

Renewable energy needs to be optimized for the season and often requires two sets of devices, for example, in summer I run a solar hot water collector and solar electric refrigerator; in winter I run a woodstove for space heat and hot water.

summer-winter modes

chris
12/11/2015 3:34:40 PM

Hi Dave, Your grid-tie system, unless you made it yourself, is code compliant and will force itself to shut off in power outages on the grid. You can't get around this for safety reasons (the code). What you can do is have elect generator + inverter/charger + battery bank, independent of the grid-tie system, Then shut-off the grid-tie when you want to use the other system. The Tripp-Lite inverter-charger has a built-in transfer switch to work with the generator(get this--it must be a 'clean' power generator). Then, connect your PV or wind or hydro conroller to both the battery bank and the grid-tie hardware (no switch needed). It'll work, but it's a bit out-of-scope because usually grid-tie's advantage is no battery bank, but sounds like you want a battery bank for gird out conditions. The only way you can skip the battery bank is if your loads can run intermittently as the PV and wind are intermittent. Hydro is continuous and is ideal if you have it. Hope that helps! Good luck, don't shock yourself or short out the hardware, and good work on using renewable energy. Chris.


dave
12/11/2015 1:15:37 PM

Chris, I currently have a grid - tied PV system. I want to add options for main, off-grid, gen, and battery but I cannot find a 4 position transfer switch. Do you know where I might find a 4 position manual transfer switch? Thanks, Dave


chris
12/9/2015 10:26:27 AM

Thanks Doug. I'm solving the backdraft problem by getting a swiveling wind cap for the stovepipe, the kind you often see on homes at the Oregon coast where the wind seems to always be present. It has a vane on the top that directs it to shield from downdraft and actually helps create the correct updraft in the woodstove. If you've seen the videos on YouTube of my small house, you'll probably notice that the stovepipe is at an angle--I'll fix that with one more elbow before I put the wind cap on. Just waiting for the snow to diminish so I can get out to the hardware store to get the new stovepipe components.


doug
12/4/2015 10:11:55 AM

A tip on the stove lighting. If you have a downdraft in the chimney (warmer outside than inside) or just no flow at all like you describe, lightly crumple a sheet of newspaper and lay it on top of your wood by the stove pipe (if the fire box is full) or half-jam it into the stove pipe (if you don't fill the fire box). Lighting that will force hot air up the chimney almost immediately. If you have a chronic no-flow situation you may need to check your chimney design. It may not be tall enough above the roof or there are close-by trees, etc. that impede its flow. What you describe isn't normal. It also sounds like you need a bigger fire box to hold enough wood, then coals, to last the night. Mine stays hot enough all night to keep the blower on - next morning add more wood and it lasts all day while I'm gone. Often the blower is still on when I get home. Also a suggestion for lighting - collect lint, rags, cotton balls, etc, old candles, and cardboard egg cartons. Some lint/rags/cotton in each divot, a good dose of melted wax, and cut them up. Best fire starters I've found (better than commercial wax-and-sawdust starters which I used for years). The starter lights instantly, no need for kindling, and it lights the wood 99% of the time w/o touching it again.





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