The invention relates to a method which comprises making a hole in a metallic support of an absorber tube, putting a vacuum pump in fluid communication with the chamber of the absorber tube by means of the hole, actuating the vacuum pump to generate a vacuum in the chamber until reaching a predetermined vacuum threshold, and introducing an inert gas inside the chamber and performing a plurality of sweeps with said inert gas, removing hydrogen from the chamber, allowing to thus reduce or remove the accumulation of hydrogen in said chamber, such that, as a result, at least part of the hydrogen absorption capacity of the getter material is recovered.

Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

The invention provides in some aspects a thermal energy collection system comprising a first solar collector through which a first heat transfer fluid flows to absorb energy from sunlight as it passes through the first solar collector, and a second solar collector that collects energy from sunlight that has passed through the first solar collector. The first heat transfer fluid of the thermal energy collection system according to these aspects of the invention is in thermal coupling with the first solar collector, but not with the second solar collector. In other aspects, the invention provides a radiator system, comprising a multi-wall panel, an interior of which is in fluid coupling with, and that forms part of, a fluid circuit through which a first heat transfer fluid flows. A reflective surface is disposed in a vicinity of a second face of the multi-wall panel. Still other aspects of the invention provide a reflective film solar energy collector and a solar energy absorber.

A roof or wall comprising an insulating selective surface (1) for the use of transferring net heat energy into or out of an enclosure, such as a building. The insulating selective surface comprises at least one transparent cover (2) that comprises a chamber (9), and in the chamber is a moveable plate (4) comprising a plurality of surfaces (5, 6). At least one of the surfaces is a selective surface which can be moved to substantially face the sky, or moved to face away from the sky. The device insulates the enclosure from conductive losses, while using the sun to heat the enclosure, or the cold of deep space to cool the enclosure depending on how the plate is moved.

The present invention relates to an automatic motion system by dilatation of a fluid, said system acting on elements of a compact solar collector with integrated storage tank, said solar collector having least a face exposed to the solar radiation and at least another face not facing the solar radiation, said solar collector comprising a plurality of primary tubes, for containing at least one primary heat carrier element adapted to the storage of thermal energy, and an external collector element arranged movable with respect to each primary conduit, adapted to overlap, at least partially, during its motion, in each primary conduit.

This invention concerns a receiver unit (10) for a parabolic trough solar plant. The receiver unit (10) has a conduit (12) for conveying a heat transfer fluid (14) and a cover (16), which is located about the conduit (12) such that a vacuum is formed between the conduit and the cover. The conduit (12) is designed to absorb thermal radiation. The cover (16) has a first portion (26) defining a window (22) through which incoming solar radiation (24) passes into the vacuum and onto the conduit (12) and a second portion (28) carrying a reflective surface (20) so as to reflect thermal radiation back onto the conduit (12). The invention also concerns a method of reducing thermal radiation loss from a parabolic trough receiver.

Provided is a solar collector that captures and utilizes solar energy and includes a plurality of vacuum tubes which are disposed by extending horizontally and are disposed parallel to each other with a predetermined distance; and a reflection plate having a substantially planar shape, which reflects solar light on an opposite side of the sun with respect to the plurality of vacuum tubes, in which the reflection plate includes a reflection surface having a serrated section at a corresponding position between vacuum tubes adjacent to each other, and in the reflection surface, one face of a serration forms a first reflection surface that reflects the solar light to the vacuum tube on a lower side among the vacuum tubes adjacent to each other.

A double line focusing solar energy collection apparatus of the present invention includes a heat collector, a secondary concentrator, and a bracket. The heat collector includes a primary concentrator and a heat collection tube, in which the primary concentrator has a focus line. The secondary concentrator has a focus line. The bracket supports the primary concentrator, the heat collection tube, and the secondary concentrator. The heat collection tube is located between the primary and secondary concentrators and located on the focus lines of the secondary and primary concentrators. The primary concentrator is a paraboloid reflector or Fresnel reflector. The secondary concentrator is a paraboloid reflector or Fresnel reflector. By adding the secondary concentrator, it achieves low light loss and high heat collection efficiency, and erosion of the heat collection tube by sand, rain, and snow can be effectively prevented, thereby extending the lifetime of the heat collection tube effectively.

The invention relates to a method which comprises making a hole in a metallic support of an absorber tube, putting a vacuum pump in fluid communication with the chamber of the absorber tube by means of the hole, actuating the vacuum pump to generate a vacuum in the chamber until reaching a predetermined vacuum threshold, and introducing an inert gas inside the chamber and performing a plurality of sweeps with said inert gas, removing hydrogen from the chamber, allowing to thus reduce or remove the accumulation of hydrogen in said chamber, such that, as a result, at least part of the hydrogen absorption capacity of the getter material is recovered.

There is herein described energy storage systems. More particularly, there is herein described thermal energy storage systems and use of energy storable material such as phase change material in the provision of heating and/or cooling systems in, for example, domestic dwellings.