Method and apparatus for preheating ventilation air for a building

Abstract

A solar air heating system for a building having a vertical, south-facing wall. The system has a perforated panel covering the wall. Vertical frame members fasten the panel to the wall to space the panel a short distance away from the wall and to form an air channel between the wall and panel. There is an air collecting space at the bottom of the channel, adjacent the wall. An air inlet in the wall connects the air collecting space to the interior of the building. A fan in the inlet draws outside air into the channel through the perforations in the panel, from the channel into the air collecting space, and from the air collecting space into the building through the air inlet.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority of Canadian application no. 2,559,641, filed 13 Sep. 2006, and which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention is directed toward a solar air heating system for buildings.[0004]2. Description of the Related Art[0005]Solar air heating systems for buildings are known. The systems are used to heat ventilating air added to buildings. These known systems comprise a perforated, heat-absorbing panel mounted over at least a portion of the outside of a south-facing wall of a building, the panel spaced a short distance from the wall to form a vertical air channel between the panel and the wall. The sun heats the panel and air adjacent the outer surface of the panel. As the panel heats, it further heats the air adjacent the outer surface of the panel. The heated air rises along the panel outer surface and passes into the air channel through p...

AI Technical Summary

Benefits of technology

[0008]It is the purpose of the present invention to provide a solar air heating system that is simpler in construction, simpler and easier to install, more efficient in use, easier to service, and lends itself to a greater variety in design of the panel.

[0010]The panel can be mounted to the building wall with vertical, horizontal or a combination of vertical and horizontal frame members depending on the construction of the panel. The frame members are fastened on one side to the building wall and the panel is fastened to the other side of the frame members. To facilitate air flow within the channel toward the air inlet in the building wall, the frame members are preferably perforated. The perforations in the frame members not only facilitate air flow in the channel both vertically and horizontally but also reduce the weight of the frame members making installation easier.

[0011]The system could be provided with a horizontal air collector duct at the bottom of the panel to collect the air from the air channel, the duct leading to the air inlet in the bottom of the building wall. While satisfactory, the use of a bottom horizontal collector duct can lead to a pressure drop in the air flow due to the abrupt change of direction of the air flow. In place of an air collecting duct, a bottom portion of the panel can be angled outwardly away from the building wall at the bottom to form an air collecting space at the bottom of the channel thus simplifying the construction. The air inlet in the building wall is centered within the air collecting space between its sides. The air collecting space, continually enlarging toward the bottom of the system, allows the air to expand on emerging into the collecting space from the channel increasing air flow in the channel. In addition, the angled panel portion faces the sun at a better heating angle improving air heating efficiency in the area of the collecting space.

[0012]In an alternative construction, the entire panel can be angled slightly outwardly to make the channel wider at the bottom than at the top. The air inlet to the building is at the bottom of the tapered channel. The air flow through the channel is improved since the channel continually enlarges moving toward the bottom. The angled panel also faces the sun at a slightly better heating angle than a vertical panel improving heating efficiency of the air.

[0013]Having the inlet located in the lower half of the wall of the building, and preferably near the bottom of the building wall, provides several advantages. With the air flowing generally downwardly in the vertical channel, the temperature profile in the channel is more uniform over its height, the heat loss from the channel is reduced since there are no hot areas in the channel, and the system is more efficient. In addition, having the air inlet into the building low down makes installation and servicing of the fan in the inlet much simpler and easier. If an air collector duct is employed, it also is located low down adjacent the inlet and this location makes it easier to attach the panel and the panel frame members, particularly their top portions, directly to the framing of the building.

[0014]Also in accordance with the present invention, the perforations in the panel are made circular. The panel can be made from siding members, which can be mounted in various positions on the building wall to provide design variations improving the appearance of the building. The circular perforations allow mounting of the siding members in various positions without adversely affecting the flow of air through the perforations into the channel.

Problems solved by technology

While satisfactory, the use of a bottom horizontal collector duct can lead to a pressure drop in the air flow due to the abrupt change of direction of the air flow.

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