What I want? Get useful energy to the household using the resources available on the property - wood.
Sure there are other resources as well. There is a lake 300m away. They say the ice on this lake is never safe. I assume this means the ice never gets thick. So far I think of this more for fishing than energy.
There are two SMALL rivers here. Comparing weather statistics with the flow I see, tells me they should be able to produce the power needed for the household over a year. Problem is that when I first moved here they were dry. And I bet they will freeze in January. So using these as a source of energy will require a lot of buffering.
Wind is to be found on a top 400m away or by the lake.
Sun is useful April - October.
My needs are:
Heating the house October - April without being a fulltime firewood handler. I think a rocket mass heater
combined with a large tank (5000L?) of water and radiant floor heating will be the solution. This will require water pumps.
Electricity to fridge, freezer, water pumps, laptop, ligths. Solar covers this April - October.
So, what my plan does not yet cover by the resources available at the property is electricity October - April, and my heating plan depends on this. This is why I started the search for ways to make rocket powered electricity. As stated, I've been looking at sterling, steam, and TEGs before I figured woodgas was the way to go. Then I came across these "cheap" TEGs that seems to solve "everything" if I can figure a way to cool them below -5C when the outside temperature is around 0C. I'm thinking there may be a way to do that makes the TEG-approach better than woodgas. I just don't know how, so I'm asking for ideas.
Pressure can move the boiling point, but it takes a major leap in pressure to move the freezing point significantly. When the desired temperature range is from -5C (or less) to 95C, antifreeze is a better approach than pressure change.
Sure there are TEGs that handles higher max temp. What do you find for cost / watt and life span of these high temp TEGs?
As mentioned, at first I wrote off TEGs as too expensive. Then I found these low temp modules for less than $1/watt. I don't know much about these modules. Actually ebay is the most scientific source of information in this case! They claim to work with 150C delta-T, in the range from -60C to +125C, which is 185C, way more than 150C.
delta-T : generated power
20C : 0,21w
40C : 0,66w
60C : 1,12w
80C : 2,00w
100C : 3,21w
So the output seems to be exponential to increasing delta-T. If it continues like that all the way to delta-T = 150C one could actually put an TEG powered compressor/heat pump to cool/heat the TEG and would end up having a machine that powers it self and creating energy from nothing! Who dare to say this is not a fantastic machine? (Never mind this machine only works in theory based on guesswork based on the data provided by a seller on ebay who probably has no knowledge of the product sold.) I ordered a dozen of them. 60 days of shipping.
Well. The topic for this thread
. How to use energy from wood/air/ground/compost/.... to provide the best possible conditions for this TEGs when outside temperature is around 0C? Hot side is easy: water heated to 95C by a rocket. What about the cold side? (Ground temperature here is about +4C.)