Even a new, minimum efficiency air conditioner or furnace can be a significant jump in efficiency. The old furnace in your basement may only be originally rated at 60% to 70% AFUE. In order to comply with national regulations, furnaces manufactured today have to be rated at a minimum of 80% AFUE.
dipole - a pair of equal and opposite electric charges or magnetic poles separated by a small distance. couple - (physics) something joined by two equal and opposite forces that act along parallel lines. electric dipole, electric doublet - a dipole with equal and opposite electric charges.
Thus, they are called intermolecular forces. There are three main types of secondary bonds: dipole-dipole, London dispersion and hydrogen bonds. Hydrogen bond is a special type of dipole-dipole attraction that occurs between a lone pair of electrons on an electronegative atom and a hydrogen atom in a polar bond. The main difference between dipole-dipole and London dispersion forces is that dipole-dipole forces occur among molecules with dipole moment whereas London dispersions occur due to instantaneous dipoles that form in atoms or nonpolar molecules. This article explains, 1.