Solar Roofs 110 Vac Quad Rod Kit

Solarroofs System 4 is freeze proof for cold climates.  This is accomplished by circulating a non-toxic antifreeze solution through the collector instead of household water.  In systems like this, the heat is transferred from the antifreeze solution to the household water by a heat exchanger. System 4 uses an external or sidearm heat exchanger called a "Quad Rod" to do this.  This heat exchanger is called a "Quad Rod" because the antifreeze solution passes through four parallel sections of copper tubing which are inside a larger copper pipe.  Water from the hot water storage tank passes through this larger pipe, picking up heat from the four smaller pipes on the way.  As the water heats, it rises naturally through the larger pipe and returns to the hot water storage tank by a passive thermosiphon process.  The antifreeze, on the other hand, is channeled back into one pipe and circulated back up to the solar collector by a pump running on household current, or optionally by a 12VDC pump which could be powered by a small  solar  panel.

Notice that at no point in the heat exchange process does the household water come in direct contact with the antifreeze. You may also notice in the picture of the quad rod at the right, that the plumbing looks pretty complicated.  The quad rod is the large vertical tube on the left.  All that stuff on the right is necessary to get the quad rod working properly. Don't panic!  The Installation manual for System 4 has detailed instructions and is yours for FREE as a PDF file at the bottom of this page. Here are a few more detailed shots of the Quad Rod assembly and other associated components.