An environment-friendly piggery comprises at least one circular or polyhedral piggery building. Each polyhedron has five sides or more, and a ventilation shaft is provided in the middle of each floor of each piggery building; each floor tilts from high to low towards the ventilation shaft from the outer edge; the top of each piggery building is provided with a exhaust gas collecting and treatment device communicating with the ventilation shaft; and the bottom of the buildings are provided with pig excreta collecting devices corresponding to the opening of the ventilation shaft. The piggery occupies a small area, has strong wind and snow resistant functions, and is sturdy and durable. The culturing process is pollution-free, and piglets, pigs, and sows can be accommodated appropriately.

An environment-friendly piggery comprises at least one circular or polyhedral piggery building. Each polyhedron has five sides or more, and a ventilation shaft is provided in the middle of each floor of each piggery building; each floor tilts from high to low towards the ventilation shaft from the outer edge; the top of each piggery building is provided with a exhaust gas collecting and treatment device communicating with the ventilation shaft; and the bottom of the buildings are provided with pig excreta collecting devices corresponding to the opening of the ventilation shaft. The piggery occupies a small area, has strong wind and snow resistant functions, and is sturdy and durable. The culturing process is pollution-free, and piglets, pigs, and sows can be accommodated appropriately.

An air ventilating unit that assists in exhausting air from a building. The unit has a housing providing an opening to the exterior of the building, the housing having moveable louvers pivotally mounted in the housing with seals between the louvers and between the louvers and the housing to minimize outside air leakage when the louvers are closed. The louvers are designed to prevent them from flipping over and becoming jammed when in an open position. Once the louvers are fully open, all the louvers will stay open with minimal fan power.

An air ventilating unit that assists in exhausting air from a building. The unit has a housing providing an opening to the exterior of the building, the housing having moveable louvers pivotally mounted in the housing with seals between the louvers and between the louvers and the housing to minimize outside air leakage when the louvers are closed. The louvers are designed to prevent them from flipping over and becoming jammed when in an open position. Once the louvers are fully open, all the louvers will stay open with minimal fan power.

A multi-layered metalized film for agricultural use comprising a reflective layer that comprises a metalized polyester film, acrylic polyurethane applied to the surface of the reflective layer, a bonding agent comprising a white-colored polyethylene material and a hindered amine light stabilizer that comprises a two and one-half percent ultraviolet light inhibitor, a fabric layer comprising a high density polyethylene woven fabric and an hindered amine light stabilizer, and a fabric layer coating applied to the surface of the fabric layer, the fabric layer coating comprising a white polyethylene coating material and an hindered amine light stabilizer.

A greenhouse building has perimeter wall frames constituted by linear materials such as single pipes, and roof frames constituted by tension wires that are extended in a stretched state in the longitudinal and crosswise directions. The tension force of the tension wires is received by the installation surface through anchoring tension wires. Only compression force acts on support posts of the wall frames and substantially no bending force acts thereon. A large building can be easily constructed using linear materials such as single pipes with a small diameter. A large greenhouse with high light receiving efficiency can be easily constructed without using heavy building materials such as steel frame materials.

A greenhouse building has perimeter wall frames constituted by linear materials such as single pipes, and roof frames constituted by tension wires that are extended in a stretched state in the longitudinal and crosswise directions. The tension force of the tension wires is received by the installation surface through anchoring tension wires. Only compression force acts on support posts of the wall frames and substantially no bending force acts thereon. A large building can be easily constructed using linear materials such as single pipes with a small diameter. A large greenhouse with high light receiving efficiency can be easily constructed without using heavy building materials such as steel frame materials.

A plug for an air vent which fits into the top aperture of the air vent prevents cement flowing into the vent when a concrete floor is laid. The vent has a peripheral protrusion and a top flange. The plug protrusion snap fits into a concave groove in the top of the vent aperture. The flange extends upward an outward from the vent top so the laid concrete floor has a slot communicating with the vent and the vent top is installed below the floor and thus cannot be easily damaged by storing and removal of produce.

A plug for an air vent which fits into the top aperture of the air vent prevents cement flowing into the vent when a concrete floor is laid. The vent has a peripheral protrusion and a top flange. The plug protrusion snap fits into a concave groove in the top of the vent aperture. The flange extends upward an outward from the vent top so the laid concrete floor has a slot communicating with the vent and the vent top is installed below the floor and thus cannot be easily damaged by storing and removal of produce.

Thin film housing structures for collecting solar energy, and associated systems and methods. A representative system includes an enclosure having an interior region, the enclosure further having a support structure that includes a plurality of curved portions. The system further includes a flexible, thin film carried by, and fixed relative to, the curved portions, the thin film being positioned to transmit solar radiation into the interior region. A receiver is positioned in the interior region, the receiver carrying a working fluid. A solar concentrator is positioned in the interior region to direct the solar radiation to the receiver to heat the working fluid. A controller is operatively coupled to the solar concentrator and is configured to adjust a position of the solar concentrator based at least in part on a position of the sun.