Earthships and Indoor Solar Systems

Solar systems such as hot-water heaters and solar-electric panels are an almost obvious component of any Earthship. These are systems we would love to embrace but simply cannot afford to buy given their market prices. However, we can and intend to go about building our own. We have been researching do-it-yourself systems for quite some time and we have viable options.

My point in this post is not to go into detail about do-it-yourself solar projects. If you are interested in these things then I strongly recommend you bookmark and spend time at BuildItSolar which overflows with DIT solar projects. My objective is to suggest, in regard to solar hot water and electric photo-voltaic panels, an interesting potential feature for do-it-yourself-ers in an Earthship – bringing the systems indoors. This is something that would be more difficult to achieve with off-the-shelf systems which come in standard sizes, but self-builders can create panels in practically any size.

In an Earthship these systems are typically installed either on the roof or on, in “Global Model” Earthships what appears to be a dedicated and sloped (optimized for solar gain?) surface on the front face of the house.

Photo-Voltaic Panels

One of the greatest challenges when it comes to building your own panels is weather-proofing. The frame itself, glazing, insulation materials … all have to be weatherproof. In addition the electronics need to be properly insulated from moisture.

Bringing the panels indoors makes all these problems go away. I am thinking that if the glazing is extended all the way up with continuous wood-framing it should be pretty convenient to install panels inside.

The DIY panels can be sized to practically any size. We are planning an Earthship with a front face of over 20 meters long, so a 50cm high strip of panels allows for almost 10sqm of safe and protected solar panels.

Solar Hot Water Panels

A solar hot water system is slightly more complicated since it involves other elements depending on the overall system configuration (boilers, storage tanks, heat exchangers, etc.). Though I will focus on the solar panels themselves I believe that bringing these panels indoors may potentially simplify the overall system.

In Earthships Vol.III Michael Reynolds introduces Mechanical U’s (“U” shaped spaces are the basic building block of an Earthship). These are U spaces which are used for functions that do not necessarily need direct solar gain (such a laundry, storage spaces, etc.). I am thinking of incorporating a Mechanical U with sloped glazing (continuous with the rest of the front face of the house) and to use that glazing as a space for installing the solar panels.

 

This of course solves the basic weather proofing issues shared with the electric panels. But I believe there may be a huge extra benefit – I wonder if having the hot water panels inside the greenhouse/corridor space solves the problem of water freezing in the pipes. I don’t know if this will actually work, but if it will, it can tremendously simplify the system. If freezing is no longer a problem then the hot-water panels can be connected directly to the hot water storage tank without any need for antifreeze (a liquid that prevents the water in the pipes from freezing) & heat exchange mechanism or drain-back solutions (that empty the water pipes in the solar panels to keep them from freezing).

In both cases placement of the systems indoors reduces the need to penetrate the outer fabric of the house for pipes and cables and also makes the panels theft-proof  (I’ve come incidentally across two reports of stolen solar panels from Earthship roofs!). In both cases it is not possible to optimize the direction of the panels as the seasons change, however a winter-optimized angle of the glazing inherently comes with an added benefit of some degree of protection from over-heating (by not facing the sun directly).

It seems to me that DIY indoors solar panels are in alignment with Earthships which are designed to be owner built. It seems that doing so comes with both huge financial savings and added-functional-value and simplicity. Too good to be true?

 

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5 Comments

  1. The glazing of the greenhouse on an earthship is set in angle that is perpendicular to low winter sun. The summer sun, however, is significantly higher above the horizon and thus the rays are partially reflected back and down in front of the greenhouse, thus reducing solar energy that actually penetrates the greenhous glass in summer. If solar panels will be placed behind the glass indoors, they will get significally less energy from the summer sun and you may experiance lack of necessary electricity for self-sustainable home unfortunately. You need really large panels to get the necessary energy from them even in case they are outside the earthship and they are properly aligned.
    Another thing to remember – photo-volatic pnels are expensive, but there are EU funding that partially compesates your expenses to buy them if you use them to provide your home with environment-friendly energy.. 😉

    1. thank you for the explanation.

      but isn’t there a similar effect with the glazing built into independently installed solar panels – that glazing would be at a similar angle to the greenhouse glazing?

  2. Perhaps placing them on the inside of the two side panels over an unheated porch area would be a compromise as you could open the inside door to allow them to thaw if frozen. In the summer, open them up like awnings to meet the higher solar angle.

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