Heat scavenger

For use with an existing heating system including a furnace having an air intake for admitting cold air into the furnace, air outlet means for distributing air exiting from said furnace, and a flue pipe defining an exhaust path to the ambient of undesired combustion gases, a portable readily detachable heat scavenger comprising:

• means for absorbing heat from said flue pipe;
• heat exchange coil means for radiating heat located in said cold air downstream of said air intake;
• a reservoir tank mounted externally of said furnace;
• means for interconnecting said absorbing means, said coil means and said reservoir tank;
• said reservoir tank, said absorbing means, said coil means and all of said interconnecting means containing heat exchange fluid;
• pump means for moving said fluid through said interconnecting means;
• said interconnecting means including restrictor means, positioned downstream of said coil means, for maintaining flow of said fluid therefrom at a constant rate, said restrictor means being chosen so that the time of travel of said fluid through said coil means is maximized, said restrictor means further being positioned upstream of said reservoir tank and discharging directly thereinto;
• said absorbing means including inner and outer concentric shell members, said inner member being in direct contact with said combustion gases, as well as in line with, and concentrically secured to said flue pipe, said inner and outer members defining therebetween a chamber through which said heat exchange fluid flows.