Abstract: A solar collector plate (2) has a solar radiation receiving front absorber plane (3) that is wiped at its rear side by a cooling liquid (4) flowing in channels (5). Cavities (7), preferably behind the channels (5) and integrated in the solar collector plate (2), and that can be closed off by the very liquid flow (4), provide a closed air volume that gives a dampening effect regarding kickbacks and pressure transients in the liquid (4).

Abstract: A solar collector plate (2) has a solar radiation receiving front absorber plane (3) that is wiped at its rear side by a cooling liquid (4) flowing in channels (5). Cavities (7), preferably behind the channels (5) and integrated in the solar collector plate (2), and that can be closed off by the very liquid flow (4), provide a closed air volume that gives a dampening effect regarding kickbacks and pressure transients in the liquid (4).

Abstract: A solar collector plate (1) comprises a dark-colored absorber plate (2) facing the sun, parallel wall sheets (4) arranged perpendicularly to the rear side of the absorber sheet (2), fixed thereto and also fixed to a support sheet (3) arranged parallel to the absorber sheet (2), whereby cavity channels (5) are provided between said sheets (2, 3, 4) for flowing cooling liquid (6) which is intended to transport heat away from the absorber sheet (2). In order to provide a good thermal contact between the liquid (6) and the absorber sheet (2) at a low rate of liquid flow in the cavity channels, the cavity channels (5) are filled with particles (7), which particles lift the cooling liquid (6) to contact with the absorber sheet (2) by means of a capillary effect.

Abstract: A solar collector having a radiation absorber (1) has a number of channels for conducting heat receiving liquid, said channels accommodating particles for capillary effect to lift the liquid to effectively sweep the sun-facing surface layer of the absorber. The solar collector is started after a prolonged operation standstill by driving a liquid pump (7) intermittently by a control unit (13) acting according to a clock-controlled program. In the intermittent start-up phase, first the pump (7) is driven for 2-4 minutes, thereafter it is shut down for a time span of about 20-60 seconds, and this is repeated two or three times before a continuous operation phase is started. Thereby air in the absorber (1) channels is expelled more rapidly.

Abstract: A solar heat collector roof comprises an absorber plate (1) for incident radiation energy and a heat exchange plate (2) placed directly thereunder. The heat exchange plate is corrugated in such a manner that it comprises channels extending down along the roof. The heat exchange plate (2) is moreover in direct contact with the absorber plate (1) thereabove. A heat carrying or heat removing liquid medium (3), e.g. water, flows in the channels. The liquid medium (3), which removes heat from the heat exchange plate (2), is supplied at such a rate that the flow rate down along the roof in the channels lies below the rate at which the surface tension of the heat carrying medium (3) is broken, so that a winding and travelling flow pattern is imparted thereby to the liquid medium (3), and up along the channel walls (4).