I layout below the approach to building low cost and and mechanically simple DIY Food projects as a guide for a global collaboration to work towards a standardized Open Source method that works well for the purpose of most DI Yers. Then, with multiple projects of this type in use we will demonstrate to people everywhere that Sola Roof is remarkably low in cost, complexity and maintenance, and can be used by anyone to grow your own food. Secure and non-toxic food from a Back Yard Project, using effective solar processes for year around growing: this is a radical breakthrough that we need and also need to share with others (see Pay It Forward).
- The DIY Kit is generally described as a Tunnel Greenhouse that uses a Metal Structure? hybrid of a Hoop Frame? combined with Roof Truss? that is supported by columns framed into the tunnel End Walls?. The metal member's strength will vary according to live-load (snow-load) specifications in each locality, for example from 15 to 30 or 40 pounds per square foot. Our standard Tunnel Greenhouse structure is designed with a dead load specification of 10 pounds per square foot (the actual structure dead weight is less than 1 pound/ft2). This live load allowance is a safety factor since snow will slide off of the Tunnel Greenhouse to the ground, but there is still the wind load. Additionally, the structure strength is required for "dead loads", which include: to carry equipment, suspend crops and/or support our optional roof level hydroponic crop production system. The structure cost, is influenced by the live/dead load specification and also will depend on the extent of the prefabrication (the frame supplied knocked-down for site assembly) of the metal kit: together with bolts and associated hardware the cost is estimated at about $2 to $4US per square foot of floor area. The structural kit provides for crop support and a base for bench growing system (more cost than other options that are sited on the ground) and our Liquid Thermal Mass system under the bench frame. The ridge Roof Truss? would typically span 20 feet, (from End Wall? to End Wall?) and, together with the Hoop Frame? forms a simple and very strong tunnel structure. Structural alloy Aluminum Frame members are produced from light extrusions or Steel Frame member are roll-formed as slightly heavier galvalum steel tubing and angle for the hoop, column, bracing and the roof truss members with various DIY film attachment profiles used to securely attach the two layer cover. The exterior hoop system gives structural support to the exterior cover - for wind and snow loads - while a lighter interior set of hoops supports the inner film layer. The interior hoops together with the ridge truss can carry suspended crop production systems.
- The Liquid Solar mechanical equipment installed in the roof/wall Cavity Space consists of many sprinklers (simple agricultural components and pipe) up at the ridge to operate the Liquid Solar dynamic cooling, which uses the Liquid Cooling process of flowing a thin film of the Soap Solution on the top side of the inner cover for purpose of cooling and dehumidifying (replacing most ventilation requirements). The other principal mechanical system is the Bubble Tech dynamic Liquid Bubble Insulation for dynamic solar heating at night (replacing most conventional heating requirement) and dynamic shading during the day. The equipment for this system is comprised of two strategically placed high expansion Bubble Generators that work in tandem or one at a time to fill the north/south sides or entire roof Cavity Space with bubbles for insulation at night from R-20 to R-40 insulation value. The Bubble Generators are mounted securely on the roof joists within the wet environment of the sealed Cavity Space and are extremely reliable because they are powered by long service life, sealed brushless motors. The Bubble Pump? associated that supplies the two Bubble Generators is usually installed on the top (unless submersed pumps are specified) of their respective Soap Solution Tank, which is along each side the tunnel and associated with benches with Liquid Thermal Mass reservoirs. Cooling water from a larger Liquid Thermal Mass components can be thermally coupled to the Soap Solution Tank by means of plastic hose loop heat exchangers inside the reservoirs comprising the Liquid Thermal Mass. These systems can easily facilitate the implementation of local cooling systems with ambient cold-water resources such as ocean, lake and groundwater for heat rejection. An optional evaporative chiller system is available to reject heat by exhausting vapor-saturated air from the Cavity Space. This process can cause a significant chilling and heat rejection (stored cooling energy) but will consume water at a rate of 1 to 2 pounds per square foot per day. The condensation that is precipitated on the underside of the Sola Roof panels is collected and together with rainfall collected from the Sola Roof can supply all the necessary make-up water (or if not needed for the chiller system is available as a potable water source). The basic mechanical system cost (for a base case of 1000 ft2) DIY Kit is $2 per square foot and another $0.50 for the chiller equipment, if needed.
- The simple double hoop system uses wide polyethylene greenhouse film with the width of the film reaching from the ridge to the ground or bench level and running any length from 20 to 200 feet for example. Each Hoop Frame?, both the exterior and interior, are covered with a suitable weight (thickness) of film. The suitable translucent or transparent greenhouse film can also meet building safety and fire code specifications. The Poly Film? or Poly Fabric? used is tough and resistant to tear or puncture (they pose no danger of collapse in earthquake events). The available Poly Fabric? covers can exceed other materials in safety, including glass and sheet metal in their high resistance to hail and hurricane force winds. The high wind resistance is due to the shape of the Tunnel Greenhouse and the continuous attachment of the covering edge using the available locking systems or similar locking profile details that is integrated into the metal members of the DIY Kit.