The Gaia house

So yesterday I posted a picture of a rocket stove heated hot tub/bathtub with a group to open the idea for an off grid and sustainable way to replace their broken down 220v electric one. One gentleman asked the question, “Why not build an outdoor rocket MASS heater tub instead?”

Well here is my opinion.

A rocket mass hot tub would actually be less efficient over all and the bench would need a limestone plaster or concrete finish with special fabrication to capture heat and prevent leaks. The thermal conduction and radiation are direct with a rocket stove tub vs. passive conduction and radiation with the rocket mass heater tub. The rocket stove tub will heat faster in the short term using less fuel, but it will not store the heat as long. With the rocket mass tub it would take up to 2 days of continuous heater use to feel the desired temperature, but would store heat for the same amount of time. It could be done indeed, but the energy output of the human would be high and the overall use of the captured energy would mostly be wasted for short term use. Rocket mass heaters are also limited to about a 30 foot run of exhaust pipe before problems arise in "draft".

So, what a perfect topic for the blog! I am always trying to push my limits on the most efficient, affordable and sustainable designs and ideas. So I have created a design for just such a thing.

For those of you that are new to rocket heaters there are two basic types, a rocket stove and a rocket mass heater. A rocket stove is just a basic chamber and pipe design much like the traditional wood stove, small ones can be used to grill and cook on and larger ones to heat buildings. A rocket mass heater will use the exhaust pipe to run through a long “cob” plaster coated clay bench to store the heat in “thermal mass”. A good example of this is the Earth; She stores radiant heat from the sun in her mass and releases it over time. Good passive solar and Earth contact homes also use this strategy. 

                                                    Rocket Stove or Rocket heater

                                                  Rocket Mass Heater

                                                                            Above 

                                                        Inside look at Rocket mass heater

So in the design we would have a two story passive solar Earth contact home, this home would ideally be built into a south facing hill side. On our lowest level we would have our bedrooms, a bathroom, utility room and recreation room with attached but open glass house and garden. In the recreation room we would have our rocket stove hot tub.  The steel tub it's self would be surrounded with a cobbed body for heat storage and a cobbed exhaust pipe, the mass of the water and cob would heat the lower level along with the captured passive solar heat. On the upper floor we would have our Kitchen dining and living space and optional second half bath. The stove exhaust pipe comes through the floor and runs through the cob bench and riser built into the living space then finally exiting the house through the roof. The exit temperatures would only be in the very low 100’s at the most with the gases being mostly Co2 and water vapor. A greenhouse on the living roof above could be added and the exhaust gas to be utilized for plant production. Co2 is a main component of plant production and helps with rapid strong growth.  The remaining heat could then be captured in the greenhouse and lowered even more. Solar powered baffles would allow for controlled ventilation and temperature in the greenhouse. Temperatures in the house can be raised by adding more fuel to the stove and/or closing baffles, they can be lowered by opening the baffles in a heat riser system. To make sure we have utilized as much energy as possible our hot water pipes AND the greenhouse floor heat pipes would also be run through the cob bench as well.

Our greenhouse roof would catch rain water and store it in cisterns, our grey water fed into our indoor garden and solid wastes composted. Our surpluses from the gardens would help feed the tilapia fish in an aquaponics system. We can also utilize worms in our composting system to supplement the protein needs of our fish and the methane produced by their solid wastes and ours would be capture and reused for a cooking stove and emergency heat or sold. The house would also utilize solar and wind technology for electric needs and surpluses can be sold for a profit. In the warm season the house temperature is controlled by natural convection, heat rises into the heat tower and out naturally creating a draft. This draft then pulls cool dry air through earthtubes outside into the lower lever and creates a cool “cave” breeze.   

Because this design uses the rocket stove hot tub it would be seasonal in this manor, a solar hot water heater above the glass house could be added if a year round tub was desired. Temperature of the tub would be determined by the amount of burn chamber exposed to the water (more exposure the hotter the water).

In the end this design along with the property creates a closed loop self sustaining system. The house is earth friendly and healthy to live in, the food is as local as it gets and completely organic and nutritionally dense. A home should nurture and protect the needs of the family living in it and should be efficient enough to run it's self. 

I would like to dedicate this blog to a very special and brave young man who is fighting cancer and to his family that has held strong through this battle. Jordon Geiser is a hero and inspires me to keep up my fight of making the world a healthier and more sustainable place for our children to live.