LifeBubble FAQ
Pure water
What are LifeBubbles?
LifeBubbles are bright, airy, human-centred ecosystems comprising rocks, soil, air, water, plants and animals. They are designed to provide essential human life support services, such as comfortable shelter from the elements, air replenishment by plants, water purification through soil fauna and microbes, nutrient decomposition and recycling into fresh food.
How are they made?
The basic concept is for them to be domes or other strong shell structures that are connected to sheltered gardens either by transparent covers or landforms oriented to maximize growing conditions. They are excavated into or surrounded by earth or rock and partially buried so that thermal mass gradients, water transpiration, condensation and ventilation can passively regulate solar energy flows and provide comfortable year-round livable spaces for humans and their food plants. Given that plants are the heart of LifeBubbles, they are mostly constructed from moist plant-covered soil, so that it is essentially a living, self-repairing structure - just like a sheltered microclimate in a natural ecosystem. They must also have dry spaces for people to sleep in, relax or interact with electrical or electronic gear.
Below is a picture of the dry earth sheltered office/crash pad space in a 5m x 10m prototype LifeBubble constructed in 2001 Photo taken on end 2009.
Condensation is an important energy transfer mechanism in a LifeBubble.
If engineered cleverly, this could be an important source of pure water.
Below shows the greenhouse section of my prototype LifeBubble. Notice the inefficient use of planting space, but even so, I was able to harvest pineapples, tomatoes, cucumbers and other produce from the small space. The rope on the ground was used to raise the polypipe hoops and their attached plastic film. This formed the main ventilation regulator. It is left down most of the time in winter and raised during the daytime in summer. It was crude but relatively effective - definitely not inter-generational. I replaced the plastic film soon after 11 years service with a far bigger 18m diameter ETFE transparent dome.
What supports the surrounding earth?
New low cost, easily mass-produced earth support materials and technologies could be developed and refined for LifeBubbles. My first prototype is a shell of ferro-cement for the earth-sheltered part and a retractable plastic arch greenhouse attached to the sun-facing side. This works really well in a temperate - subtropical climate, but materials and methods need to be adapted to make LifeBubbles more accessible and capable of enclosing a much larger planting area. A key objective of the LifeBubble concept is for them to be very long life-cycle structures (more than 1000 years) so there is a lot of work needed to find the right materials that will not deteriorate over the millennia. The simplest idea I have been able to come up with so far is for an excavated trench with sloping side walls excavated into the earth and having a cheap and simple arch canopy of ETFE.
Can the living space of LifeBubbles be excavated directly into earth or rock?
Yes, around the world there are many examples of cave homes that are sculpted directly into the earth or rock faces. Some famous examples are:
Cappadocia region of Turkey - hundreds of homes as well as shops and ancient churches.
China - over 30 million people live in sculpted earth or rock homes and about 1.6 million live in large natural caves!
How deeply are they buried?
To achieve passive climate control, LifeBubbles need to be excavated into the earth or rock so that excess solar energy can be transferred into the surrounding earth. Think of a LifeBubble as a large solar soil heater. During the day, sunlight enters the enclosed living space through a transparent cover. In tropical areas, where soil temperatures are already comfortably stable at about 20 - 26 °C, it could just be a screened canopy. During summer, large amounts (up to 80 kwh) of solar energy is absorbed by the structure and in particular by the plant surfaces. The leaves are cooled by transpiration, which converts the solar energy into latent heat in water vapour. Soil temperatures and ventilation control the amount of this latent solar energy being transferred back into the supporting structure through slow condensation and thermal storage in the coupled soil mass. It’s a neat synergy that forests have refined over the last half a billion years. Moist soils can store huge amounts of thermal energy as they have a high thermal mass. If it were not for their large thermal mass, LifeBubbles, with all the solar energy input into what is essentially a greenhouse, would become way too hot during the day. In winter, the solar energy input is typically less in higher latitudes, but the temperature does not vary much because of the heat radiating from the surrounding thermal mass. Ventilation is restricted to conserve heat and increased to shed it. Even though this method is surprisingly intuitive in maintaining comfortable conditions, it could be easily automated to fluctuate between predetermined comfortable temperature limits.
Where can LifeBubbles be located?
In theory, life bubbles could theoretically be built anywhere, from the tropics to the arctic tundra or even on the moon or Mars. It is all a matter of balancing solar storage and thermal loss. Like a solar water heater, the orientation of the collector and the heat transfer efficiency will determine the stored thermal performance. Deep space radiation loss from the soil thermal mass in some very cold, windswept locations can be reduced by thermal insulation if there is insufficient snow or vegetation cover, but they should still be comfortable spaces if solar energy is transferred efficiently to the surrounding soil. It is worth noting here that if the soil temperature is very low to start with, it can take some time to reach a comfortable equilibrium. Even in my LifeBubble in Maleny, Queensland, the soil temperature at about 1m depth started at 17 °C and took two and a half years to get up to a comfortable and stable temperature of about 23°C . An interesting phenomenon happens during this warming up period too. If the wall temperature is below the dew point and the humidity is high, you get liquid condensate starting to cover the walls. With the right design this is not a problem but if it is a problem, then you basically need to shed more latent heat through ventilator. With smart design, I am sure it can be turned into a resource to harvest chilled distilled water overnight from deep space radiative surfaces.
Can you seriously grow food in LifeBubbles?
The answer is "Yes", and it is significantly more productive than growing food in the open. Birds, insects and animals take significant amounts of food grown in open less protected gardens. The other obvious benefit is the stable temperature. There are a group of plants that like the same temperatures as people do. I can grow pineapples in the open here in Maleny Queensland but they struggle with the cold in winter. In our LifeBubble however they thrive, birds and rodents don't steal them and they are deliciously sweet. My kids can't wait for them to ripen!
To get serious about growing useful quantities of food, however, you need decent-sized enclosed spaces. A 20m diameter dome with a 13m diameter growing space gives 132m² which is what would be needed to provide most of the fruit and vegetable needs of a few people. It would also give about 150 m² of dry floor space for living and leisure.
One negative I have found with growing pumpkin and other members of this family is that powdery/downy mildew fungus tend to spread easily in the warm humid air. We still get a good crop because the plants are very vigorous, but the plants don't live as long as they do in the open air. There is obviously a need to learn how to best manage the agronomy of the chosen food crops so they are as productive as possible in LifeBubbles. Any agronomist out there up to this challenge? (After some more years of experiment I have observed that irrigating the leaf and stem surface with liquid compost dramatically reduces this problem - possibly a competitive exclusion thing.)
How to produce drinking water?
Water is always cycling through natural ecosystems. It starts when water vapour evaporates into the air, then condenses as relatively pure rain or dew but ends up contaminated with salts and nutrients. Efficient ecosystems recover and recycle the nutrients valuable to life, in particular to plants. The amount of pure water you need to drink and cook with is surprisingly small and could easily be obtained from the distillation of the water transpired in a LifeBubble.
Some of the water is lost to cooling if ventilation is the main way to shed heat. But there is room to develop innovative ways to shed excess thermal energy, like deep space radiators coupled to a large thermal mass. This could then mean that what is transpired could be recycled, just like in the biosphere. Condensed water would soak into the soil and percolate down to fill either a natural or artificial aquifer or below-ground tank. Once again, lateral thinking is needed regarding the design of this type of tank so that the water could be captured and then stored well above head level. This would mean that transpiration and gravity together would provide all the pumping needed to supply a constant supply of pure water to LifeBubbles.
Rainwater is, of course, an even easier option if it is available. So the question relevant to LifeBubbles in most regions of the world may become not where you will get the water from, but how you will use the excess. The obvious answer is for some of it to be used for cleaning, washing and waste disposal, but that question deserves its own FAQ.
What is Biolysis?
Biolysis is the process of treating used water and recycling nutrients. This is an area in which I have considerable experience having developed the concept of the Biolytix treatment process through eco-mimicry.
First, some basic used-water facts:
A water conscious (but not stingy) person produces about 70 - 90 litre a day of used water if the water is sourced from a low-head gravity supply.
Most of it will be hot water @ 40+ ° C
Five people need about 1 m² footprint of Biolytix treatment area to adequately pre-treat used-water so that it will not block or degrade the soil it irrigates.
Only 40 - 60 cm depth of modified active sandy loam soil that is planted is then needed to produce very high-quality water that will be odourless, colourless and crystal clear with typically zero total coliforms present in 100 ml. (Based on an irrigation rate of about 10mm/day)
This soil-filtered used water can be allowed to percolate deeper into an artificial aquifer/storage tank for recycling to a hot water heater.
Up to 5mm/day will be used by plants for their growth, but this is transpired and available to be condensed into pure drinking water again.
With a low sodium diet, this water can go round and round through the LifeBubble's planted food ecosystem, indefinitely producing food, recycled water and distilled drinking water.
LifeBubbles as fire shelters
After the 2009 devastating fires in Victoria, I have had some friends ask if there is any way to make a safe structure in some of the eucalyptus-dominated ecosystems around Melbourne.
Eucalypts are basically fire weeds, and some species rely on catastrophic (for humans, that is) fires to rejuvenate themselves and their fire-adapted ecosystems. For wet sclerophyll forests, the absence of fires over too long a period will allow the fire-intolerant rain-forest species to take over. These species can propagate in low-light conditions in undisturbed forests and grow up between the eucalypts. Once well established, they alter the humidity level in the forest and this can significantly reduce the risk of fire. Eventually, if there are no fire incursions for a few hundred years, they will displace the wet sclerophyll. If the conditions are very dry and a wildfire starts, the young rain-forest would be wiped out in all but the moist gullies. But the eucalypts will have shed their seeds into the ash-bed and can regenerate en masse along with other fire-dependent or fire-tolerant species in the ecosystem. It's a slow dance that takes place on a time scale of hundreds of years. First I should say that I'm not an expert on fire engineering, just an observer of nature. When faced with a challenge like this I instinctively cast about for natural analogues.
I ask myself, "Besides humans, what other slow-moving, fire-vulnerable animals live in these forests that are dependent on intense fires to regenerate?"
Not surprisingly the answer is, "Not many."
Very few surface or tree-dwelling animals can survive the furnace-like intensity of a firestorm. Winds force the intense heat into the crowns of sclerophyllous species (not just the Eucalypts) and volatilize combustible oils and gases that literally explode like the petrol vapour in a carburettor. Such firestorms arc right across moist rain-forest valleys moving at incredible speeds that no animal can possibly outrun. It’s a dramatic way to regenerate and ensure the survival of an ecosystem. The majority of arboreal animals in these forests are simply incinerated but amazingly there is a rush of new arboreal life from surrounding forests almost as soon as the fire has passed. The interesting and relevant animals are those that can actually survive the fire. As far as I know, they are all animals that dig or borrow burrows. They go down under the soil for protection. Snakes, lizards, mice, rats, wombats, and even lyrebirds use disused wombat or other animal burrows. htttp://www.parkweb.vic.gov.au/resources/14_0977.pdf
The wombats are perhaps the most interesting survivor example for us to learn from as they are quite big and slow moving. The earth has so much thermal mass that the temperature remains survivable even at the entrance of a wombat burrow. http://www.kinglakefirewombatgirl.com/
The incredibly strong winds that are sucked into the fire and fan it forward are less prominent below grade. I suspect this has something to do with the ground effect on turbulence. Whatever the reason, high humidity zones in gorges and gulleys, as well as burrows, seem to provide significant fire protection.
This is perhaps the reason why fossil plants such as the Wollemi Pine in the Wollemi Gorge and Cabbage Tree Palms of Finke Gorge National Park in central Australia or King Fern in Carnarvon Gorge, Central Queensland survive. These ancient plants have no or low fire resistance but have been able to survive in canyons and gorges within fire-prone habitats as the land surrounding them dried out and became increasingly fire prone.
For all these reasons, it is my guess that LifeBubbles with a used-water irrigated planting of moist fire resistant rain-forest species around and in it, would survive a wildfire well. LifeBubbles have all the survival features exhibited by those very special natural habitats that contain rare or ancient plant relics and remnants that can survive fires.
These features are:
below the general surface grade
sheltered from strong hot winds
moist plants around and within it that can transpire extra water when heated, to increase the relative humidity (i.e., decreases combustibility)
sheltered by the earth and particularly moist earth.
The rebuilding of bush fire-ravaged communities in Victoria would be using very different design principles if the people involved used eco mimicry principles to do two simple exercises.
Look for habitats that are in fire-prone areas that contain fire-intolerant species that have survived in that location for millions of years and observe what the key features are.
Study the location of tunnels of fire survivor animals such as wombats, which have co-evolved in fire-prone habitats, and during fires take measurements to understand the air movement, oxygen content and temperature variations within the tunnels during a high-intensity fire.
LifeBubbles are inter-generational structures, so these are research priorities for people planning LifeBubbles in areas where high-intensity fires can occur.