Perforated transparent glazing for heat recovery and solar air heating

Abstract

A heat collector comprises a transparent glazing exposed to the ambient. The transparent glazing is spaced from a back surface to define a plenum therewith. A plurality of perforations is defined through the transparent glazing for allowing outside air to flow through the transparent glazing into the plenum and substantially maintain the transparent glazing at the ambient temperature, thereby providing for higher thermal efficiency.

Description

TECHNICAL FIELD[0001]The present application generally relates to a device suited for pre-heating fresh outside air by means of free energy, such as solar energy and / or heat recovery.BACKGROUND ART[0002]Design of traditional glazed solar air heaters generally comprises a glass, polycarbonate or Lexan® transparent cover placed in front of a dark solar absorber. The front transparent cover is provided for minimizing heat losses from the top of the collector. Fresh outside air is traditionally admitted at on end of the collector between the front transparent cover and the solar absorber. The air passes through the collector along fins and absorbs heat from the solar absorber as it travels therealong. Warm or hot air is discharged at the opposite extremity of the collector. As air progresses inside the collector, its temperature rises above ambient. The higher the temperature in the collector is, the higher the heat loss towards the ambient becomes. Heat loss happens through the bottom,...

AI Technical Summary

Benefits of technology

[0007]In accordance with another general aspect, there is provided a device for heating air, the device comprising a perforated transparent surface allowing solar radiations to pass therethrough, a solar radiation absorbing surface located behind the perforated transparent surface for absorbing the solar radiations, and a gap of air defined between the perforated transparent surface and the radiation absorbing surface, the air flowing in the gap absorbing heat from the radiation absorbing surface while fresh ambient air flowing through the perforations of the perforated transparent surface providing for a minimal temperature delta through the transparent surface.

Problems solved by technology

When the glazing becomes very warm, the collectors become less efficient.

However, for unitary flow rates below 5 cfm per square foot, the amount of cool air leaching the perforated plate is insufficient to prevent the collector plate from heating up, thereby negatively affecting the overall thermal efficiency of the system.

Images