As we mentioned on homepage, SolaRoof is the core or the soul of PyraPOD, with the latter being the embodiment of the former. The reason is, the physical and structural shape can be anything you see on this page to the left and right – click to see larger image, but the core principles remain the same.
To give you a nutshell about SolaRoof, its name says it all. It carries three meanings: (1) Solar Roof – in this sense it is like a passive solar greenhouses to capture the sun light as much as possible. However, capturing solar energy is just one aspect, storing and using it to create a comfortable zone are far more important. This is something a traditional one layer greenhouse cannot do, which leads us to the next point…
(2) SolaRoof also means Roof Only – in order to capture the solar energy and create a comfortable environment, we need to focus on the Roof only. In the case of greenhouses, the entire envelope or canopy is the roof. However, we have here a contradiction or balance between these two extremes: more light in means less insulation capability (normally measured by a heat resistance factor or the so-called R value). The same for the reverse: a higher R value means less light transparency. That is why we see most buildings having opaque walls and a roof with relatively small windows. Why? For better energy efficiency.
(3) Sole and Roof – Sole in definition, refers to the undersurface of a person’s foot, which in the case of PyraPOD, points to the thermal mass we use to store the solar thermal energy we collect with soap bubbles which flow back to a tank that is most often placed on the ground or below grade for better result. If a heat exchange mechanism is implemented betwen the soap liquid and the water in sandponics/aquaponics system, then geo thermal can be easily incorporated into the whole picture. In the case of iAVS sandponics, sand itself is a good thermal mass which increases the capacity for heat storage. As a result, the thermal energy collected and stored during the day happens to be just enough for the night use. That is what the inverted pyramid means in our logo displayed to the right.
To accomplish al the above three functions of SolaRoof, we use two layers of transparent membranes as the roof or covering. More importantly we have to dynamically fill the cavity with something that offers a great heat resistance. And this something has to be formed on demand and disappear as needed. No, it is not air blown in all the time, 24/7 for cold winter days, as most people do. Yes, this something is soap liquid bubbles – what else could we use?
Similar to the two-phase transition between water vapor and its liquid form, we have found a solution that has better dual properties: soap liquid is wonderful thermal mass while soap bubbles are excellent insulation materials when the air is trapped in tiny cells. Contrary to the vapor-water phase transition, transformation between soap bubbles and soap liquid does not trigger or need a thermal energy gain or loss. We can simply use a water pump and an air fan. That’s it. Easy Peasy! Watch it in action in this video:
Now take a look at the following for SolaRoof in action at night time or in winter season when the outside is really cold…
You see, soap bubbles fill the entire cavity and insulate every corner and space to form a canopy just like the atmosphere around the earth. You bet what will the inside be like when you have a highly insulated and sealed barrier all around, left and right, up and down. As a rule of thumb, an inch thick of soap bubbles will be equivalent to a heat resistance or insulation property of R1. If the double layer cavity is two feet or 24 inches in thickness, then we can achieve R24 easily with only soap bubbles trapped in between two poly films.
What happen when the sun rises and especially in summer time when the inside is really hot and you wish there is shade? Take a look at the following image showing how bubbles can give you just that. In addition, geo-air or geo-liquid supplemental thermal heating/cooling can also be easily incorporated into the picture as shown here:
As you see above, beside having a thick layer of bubbles as shade for the south side, we also have a thin film of soap liquid flowing down on the north side. While the south side gives us the shade needed and the north the max indirect light transparency, both sides still hold the capability of absorbing solar energy and store it in water in the form of thermal energy – this is also a cooling effect when we do not want the inside to be too hot. In fact both sides have trays at the bottom to take the falling soap liquid and let it flow back to a central tank where it is pumped up to roof in the first place. This way, the extra solar thermal energy we do not need is stored and to be release slowly and readily when the sun sets down at night.
Watch how the thin soap liquid film flows nicely in action:
The following data shows the change of four temperatures recorded in 1994 (looking at the central section, from top to bottom) with light blue for soap liquid tank, dark blue for inside, red for bubbles in the middle, and black for the outside:
If you can foresee it further, a simple setup like this can literally achieve at least the following 7-in-1 functions:
- Light and yet sturdy structure
- High transparency fabric covering
- Easy liquid/bubbles generation & transformation
- Dynamic dual insulation & shading capabilities
- Controlled and sealed environment with enriched CO2 and recycled water for growing
- Useful byproducts – clean water from condensation and algae biomass
- Open and eco design – low cost life support systems for self reliant homes and communities