Odd/Interesting/Unusual Renewable Energy Projects

A collection of innovative, creative, out of the ordinary, crazy, goofy, and sometimes amazingly inventive and practical ideas and projects.

Solar coffee roasters, water powered tracker, solar refrigeration, water rollers,

Got an "odd" project -- please send it in!

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Interesting Projects
Mirror gives Italian Village Its Place in the Sun



"ROME (Reuters) - A village in the Italian Alps is finally basking in winter sunlight thanks to a giant mirror installed on a mountain top to reflect the sun's rays into the main square."

They use a heliostat to reflect sun into the town square.  I've thought about doing this (on a much smaller scale) to reflect light into my east facing living room windows.

Solar Bubble Build



Pretty detailed description of a building using the soap bubble insulation scheme.

I'd say this is on the experimental side, but the idea has been used on some "real" greenhouses -- quite an interesting concept!

Hippo Roller water transport 
From Inhabitat.com

http://www.inhabitat.com/ ...


An easy way to transport several days worth of water for a family.

The best designs are the simple ones.

A Solar Water Heater Made of PET Bottles


http://www.temasactuales.com/ ...

Instructional Manual:

English Translation of Manual:
Construction Manual in English ... (pdf)
(Thanks to Chris for finding this!)


An interesting solar water heater design made from PET bottles.  It looks like plastic(?)  pipes run up the center of each row of PET bottles.  The PET bottles (I think) act as glazing, and also hold reflectors made from beverage cartons(?)

The Instructional Manual has a lot of good pictures that make it fairly clear how it goes together.  
Its an inventive design with most of the materials coming from stuff that would otherwise go to the landfill.

(Thanks to Cameron and Tom for providing more info on this.)

Roasting Coffee on Sunshine

How to get articles from Home Power ...

Issue 105 Home Power Magazine

How to build a 1200F solar coffee bean roaster.

A very large pipe coil solar pool heater




This is the Mother of All pipe coil solar pool heaters.  It uses 4000 ft of black poly irrigation pipe. 
Very nicely done, lots of good detailed pictures, and some performance data.
Its in Spanish, but the Google "translate" button is your friend.
My Shower Curtain is a Green Warrior



This  is one way to stop your teenagers from taking those hour long showers :)
The Rutgers Solar Heating System for Greenhouses
Mears, Roberts, Simpkins, and Kendall
Rutgers University

The Rutgers Solar Heating System for Greenhouse - 1977 (0.8 MB pdf)

Greenhouse Solar Heating-1981 (2.5MB pdf)



A related paper on a solar home using a similar flooded subfloor heat storage scheme.

The solar collector shown here was developed in the 70's as a very inexpensive greenhouse heater.  It works well for situations in which only low temperatures are required (like greenhouses and pools).

While I do not know of anyone who has tried this as a pool heater, it seems to me it might work well, and it would be very inexpensive -- perhaps $2 per square foot?

The papers give information on a several greenhouse energy schemes, so you have to wade through all this to find the details on building the collector.  The collectors described in the paper are quite large, but could be scaled down.  Note that even though this is a very simple collector, there are details that you must get right for it to hold together -- so read all the construction notes.

If you build one of these PLEASE let me know -- Gary

A number of other interesting commercial greenhouse related papers at the Rutgers Horticultural Engineering Website: http://aesop.rutgers.edu/~horteng/

The Snail Shell System





Just could not pass this up.

I think I would need a window.

The James Hand Washer


Another supplier of human powered washers:



Person powered washers, clothes drying hardware, and other interesting stuff.
Accelerated Composites Aptera


The FAQ page has most of the details...

More from AutoBlogGreen on Aptera...

The Accelerated Composites Aptera will be produced as an all electric and as a plug in hybrid.   Seating for two adults + an infant seat behind.     Zero to 60 in 10 secs, top speed around 85 mph.  Drag coefficient of 0.05., weight 850 lbs, range 120 miles(?).

While it is licensed as a motorcycle, they have put a lot of emphasis on safety including air bags and front, side, and rollover protection.

Their goal is to offer the EV version in late 2008 and the hybrid version in late 2009  -- prices projected to start at $27K.  Pretty exciting vehicle.

Solar Still

ElPaso Solar Energy Association

solar still plans ...

Plans for a solar still used to purify water.  Report on daily output.
The Bruce Weiner MicroCar Museum



Fascinating collection of Micro Cars. These very small and efficient cars were developed in Europe in the rebuilding times after world war II.  

Many on display in Madison, GA
Bert Race


This has less than nothing to do with solar energy, but I just could not resist.

David Goes Electric

Bruce Johnson

How to get articles from Home Power ...

Home Power Magazine article, issue 53

Interesting article on converting a walk behind gas tractor to electric power on a budget.


Hot Water, Cold Beer


Doug's homemade heat pump that efficiently cools his beer kegs and heats domestic hot water.

Its a heat pump that pumps heat out of the beer and into the domestic hot water tank.

All the details ...

Spiral Pump



The Spiral Pump - A High Lift, Slow Turning Pump, Peter Trailer

Wild Water Power -- more spiral pump information:



This pump uses a rotating pipe coil to pump water.  It requires only moving water to power it.

The pump in the picture pumps 400 gallons per day to a tank 50 ft above the pump.

The Spiral Pump - A High Lift, Slow Turning Pump, Peter Trailer
Very interesting set of tests on a spiral pump.  Quite a bit of design and construction information is also provided.

Sometime I am going to have to sit down an figure why this works :-)

Dog Powered Scooter



Yes, I can just see my dog doing this -- not.
Water-Powered PV Tracker
Bill Spurlock

How to get articles from Home Power ...

Home Power magazine article, issue 85

Describes a clever solar panel tracking system that uses gravity feed water to power the tracker.



An interesting and eclectic collection of information.  Lots of information on heliostats and simple but effective solar tracking systems.
Harvesting water from fog

OAS article on Fog Harvesting...

Article from Inhabitat...

Areas that have frequent fogs (eg some coastal areas) can harvest water fairly efficiently and inexpensively from from the fog using nets.
Beer Bottle Solar Water Heater,
Ma Yanjun



An unusual approach!

I guess you work with what's available.

Building a Simple Sterling Engine
Jay Wilson

How to get articles from Home Power ...

Home Power Magazine article, issue 76.

Interesting article on building a demonstration level Sterling
engine from hardware store parts.

Single Seat Volkswagen


US News Article...


This single seat car that VW is working on would get 250+ mpg, top speed 75 mph.  It can travel over 400 miles on its 1.7 gallon fuel tank!  Weighs 660 lbs.
This car is powered by gasoline only, and its 250 mpg is not one of the phony plug in hybrid mileage ratings that does not include fossil fuel burned to make electricity -- its an honest 250 mpg -- amazing.
Said to be ready to go on sale in Shanghai in 2010. 
A Low Tech Hot Tub & Solar Heater



Here is a low tech hot tub and a simple, but effective solar and wood burning hot tub heater.

More on the new version of the collector...

And a start on a temperature controller for the hot tub ...

(I think there is some risk here of getting the plastic pipe to hot if the collector stagnates -- see notes on our PEX collector and stagnation)

Water bed cooling Randy suggests that in hot climates sleeping directly on the water bed bladder will be cooler.
Remove all the coverings except for a sheet or two, and let the water conduct heat away from your body.
The temperature of the water in the bladder will be the average of the last few days, and cooler than body temperature.
After more experience, Randy adds that during the cooler season, you want more insulation (e.g. a blanket) between you and the water bladder to keep it from getting to chilly.  Its a mater of adjusting the amount of insulation between you and the thermal mass.

A Solar Ammonia Absorption Icemaker

Jaroslav Vanek, Mark “Moth” Green, and Steven Vanek


How to get articles from Home Power ...


Home Power Magazine article, issue 53

Interesting article describing a demonstration level solar refrigerator using Ammonia as the refrigerant and a parabolic trough solar collector as the heat source.  The article may be available as a free download at the first link, if not, search the HP achieves for issue 53, and order the download.

Bubble Wrap Window Insulation



New Installation Instruction Sheet (8/15/06)

AND, The Card Board Shutter
Based on the popularity of this Bubble Wrap window treatment, here is a Cardboard Shutter

A really cheap and quick way to insulate windows that you don't need a clear view out of.

Added some small updates to instructions 11/13/05.
Instruction sheet added 8/15/06
Reported life of bubble wrap added 2/27/07

Another cheap (but very effective) window insulator Card Board Shutter -->

Solar Heated and Insulated Horse Tank - Version 2

Full details - performance and construction ...


Newest version of the solar heated, well insulated, double glazed horse/stock tank.
Full construction step-by-step.

All the details ...

True DIY Heat Pump Projects

The Homemade Heat Pump Manifesto...


Multi part EcoRenovator blog on DIY GSHP...


These are two long (as in 22 pages) posts on completely DIY ground source heat pump projects.  The heat pump units are made from salvaged AC units.  The projects even include homemade rigs to drill the boreholes for the geo exchange loops.  Very good detail.

The EcoRenovator site and forum have some fascinating, unusual, and hard core DIY energy projects.

Fran's Use of Subterranean Air to Defeat the Evil Air Conditioner


The whole story...

Fran shows how he used cool air from his basement to defeat the evil air conditioner.

A nice simple and effective system and a well written story ...

Homemade Pipe Radiator These pictures show a radiator that is used to heat the visitors center in Dawson City, Yukon Territory -- according to the staff it does an outstanding job.

More pictures...

Homes from Steel Grain Bins


Its Not Just a Grain Bin...It's a Home...

More... And...

One using strawbale insulation...


This is an interesting idea for a home. The bins have a good ratio of wall area to internal volume.  You could add as much insulation as you like, and this could be done with no thermal bridging. 

Once you start looking for these on Google, you find there are a lot of them.

Rotating Solar Home


A rather unique solar home that rotates.

Maybe this should be in the "active solar" section :-)

A More Efficient Shower




A shower idea that reduces heat losses and air currents so that you can have a comfortable shower with less water that is less hot.
Interesting story and prototype.
Steam Power - An Introduction

How to get articles from Home Power ...

Home Power Magazine article, issue 62

Good article on with quite a bit of detail on how to size,
design, and even build a steam engine.

Bill Lishman's Underground House



Bill Lishmans's unique and beautifully done underground home.
Beer Can Solar Air Heating Collector


Original Hungarian version:

English Translation:


And another from Brian ...

This is a nicely done and well documented version of the alum beer can collector design -- similar to the CanSolar commercial collectors.


More about the builder and collector ...

A pretty good video on the CanSolar collector with some construction detail ...

Sleep Genie -- A sleep Compartment with AC


From Sunfrost

An interesting concept to provide a comfortable, air-conditioned environment in a limited space for sleeping comfort. 

It saves the energy cost of needlessly air-conditioning a large space when your are only occupying a small space.

Solar Heated Ice Fishing Shack

All the details from Bob...

Solar collectors are not just for heating homes -- Bob uses this very simple and effective thermosyphon solar air heating collector to heat his ice fishing shack.

It cost almost nothing to build, and heats the insulated fishing shack very well.

All the details from Bob...
Our own "Experimental" page ... Our own collection of experimental ideas and projects.
Solar Autoclave Using Evacuated Tube Collectors

Sydney University, Australia

Solar Autoclave Paper (pdf)

A solar powered autoclave that uses evacuated tube collectors as the heat source.

Two sizes described.  The smaller size uses only one evacuated tube.