The physics & engineering of continuous-cycle absorption heat pumps is fascinating stuff. Calculation suggests that intermittent-cycle refrigeration is potentially more efficient, or at least a better fit for PV power - CC is cheaper to fab, though, which is probably why you don't see IC these days; I'm suggesting that a PV + IC system that does'nt need a battery would offset the extra expense of IC, with considerably improved reliability. Batteries, as noted elsewhere, are expensive and trouble-prone... --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .