Transwall
From Swikipedia
Introduction
Transwall is a thermal storage wall that is semitransparent in nature. It partly absorbs and partly transmits the solar radiation. The transmitted radiation causes direct heating and illumination of the living space. The absorbed heat is transferred to the living space at a later time. Heat loss through the glazing is low, as much of the heat is deposited at the centre of the transwall ensuring that its exterior surface does not become too hot. Thus, the system combines the attractive features of both direct gain and Trombe wall systems.
Brief Description
A transwall has three main components:
• Container made of parallel glass walls set in metal frame
• Thermal storage liquid, which is generally water
• A partially absorbing plate set at the centre of the transwall, parallel to the glass walls
It is installed on the south side of the building (in the northern hemisphere), located directly behind double glazing. To prevent the growth of micro-organisms in the storage, an inhibiting agent may be added.
Variations and controls:
The dimensions of the storage module are dictated by the hydrostatic pressure exerted by the liquid. Also important, are the considerations of transportation, the method of installation, the ways of filling and draining the module, and attachment of the modules to each other and integration with the building.
As the storage is a convective body of water, the transfer of heat is rapid. This can be regulated by providing baffles and adding a gelling compound. Baffles are transparent plates which connect the module walls with the absorbing plate and prevent water movement. The gelling compound increases the general flow resistance.
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