<story><title>Heat Your House with a Water Brake Windmill</title><url>https://www.lowtechmagazine.com/2019/02/heat-your-house-with-a-water-brake-windmill.html</url></story><parent_chain><item><author>Animats</author><text>The article doesn&amp;#x27;t show a single non-demo installation.&lt;p&gt;This thing looks like a giant mechanical kludge. If you put the brake (the paddles in water part) at the top of the tower, you have to pump water up the tower. If you put it at the bottom of the tower, you need a top gearbox with a right-angle bevel drive, a bearing ring supporting the gearbox so it can face the wind, long shafting, and bearings.
Some early power turbines were built that way, but nobody does that any more.&lt;p&gt;Vertical axis turbines like the Savonius turbine and Darrieus rotor can be used, but they&amp;#x27;re not very efficient, so you need a big one. They also are hard to shut down in an overspeed condition; they can&amp;#x27;t change direction, change blade pitch, or tilt upward, so you need a strong emergency brake system. Which is why they&amp;#x27;re rarely seen any more.&lt;p&gt;All this outdoor hot water plumbing needs to be well insulated, or you lose most of the heat.  So a field of wind turbines, or one unit some distance from where the heat is wanted, is a problem. Moving energy around over wires is so much simpler.&lt;p&gt;Driving a heat pump mechanically might work better, but that&amp;#x27;s because heat pumps are far more efficient than heaters. (Moving heat is much cheaper than making it. See [1]). An electric windmill driving a heat pump is probably less hassle.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;dothemath.ucsd.edu&amp;#x2F;2012&amp;#x2F;06&amp;#x2F;heat-pumps-work-miracles&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;dothemath.ucsd.edu&amp;#x2F;2012&amp;#x2F;06&amp;#x2F;heat-pumps-work-miracles&amp;#x2F;&lt;/a&gt;</text></item></parent_chain><comment><author>twic</author><text>&amp;gt; If you put the brake (the paddles in water part) at the top of the tower, you have to pump water up the tower.&lt;p&gt;You have a windmill, so you have a source of energy to do that. Much of the mechanical energy that goes into the pumping becomes gravitational potential energy, which will become heat when the water goes back down the tower. A lot of the rest will be lost as heat during pumping. Either way, it&amp;#x27;s ending up as heat, which is what you want.&lt;p&gt;Heaters are the only type of machine which are naturally efficient!</text></comment>
<story><title>Heat Your House with a Water Brake Windmill</title><url>https://www.lowtechmagazine.com/2019/02/heat-your-house-with-a-water-brake-windmill.html</url></story><parent_chain><item><author>Animats</author><text>The article doesn&amp;#x27;t show a single non-demo installation.&lt;p&gt;This thing looks like a giant mechanical kludge. If you put the brake (the paddles in water part) at the top of the tower, you have to pump water up the tower. If you put it at the bottom of the tower, you need a top gearbox with a right-angle bevel drive, a bearing ring supporting the gearbox so it can face the wind, long shafting, and bearings.
Some early power turbines were built that way, but nobody does that any more.&lt;p&gt;Vertical axis turbines like the Savonius turbine and Darrieus rotor can be used, but they&amp;#x27;re not very efficient, so you need a big one. They also are hard to shut down in an overspeed condition; they can&amp;#x27;t change direction, change blade pitch, or tilt upward, so you need a strong emergency brake system. Which is why they&amp;#x27;re rarely seen any more.&lt;p&gt;All this outdoor hot water plumbing needs to be well insulated, or you lose most of the heat.  So a field of wind turbines, or one unit some distance from where the heat is wanted, is a problem. Moving energy around over wires is so much simpler.&lt;p&gt;Driving a heat pump mechanically might work better, but that&amp;#x27;s because heat pumps are far more efficient than heaters. (Moving heat is much cheaper than making it. See [1]). An electric windmill driving a heat pump is probably less hassle.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;dothemath.ucsd.edu&amp;#x2F;2012&amp;#x2F;06&amp;#x2F;heat-pumps-work-miracles&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;dothemath.ucsd.edu&amp;#x2F;2012&amp;#x2F;06&amp;#x2F;heat-pumps-work-miracles&amp;#x2F;&lt;/a&gt;</text></item></parent_chain><comment><author>lowtechmagazine</author><text>&amp;quot;The article doesn&amp;#x27;t show a single non-demo installation&amp;quot;.&lt;p&gt;It does. The Calorius windmill was commercially produced for about a decade, 40 of them were sold. Seventeen of these windmills were still operating in 2012.&lt;p&gt;It&amp;#x27;s all in the article. Also your points about the savonius are addressed.</text></comment>