The invention relates to a method of heating a fluid (9) containing dipolar particles, such as molecules or clusters of molecules, whereby the fluid (9) is subjected to an electric field in a heat generator (1) causing its particles to be oriented according to their charge. Voltage pulses are applied to the particles, as a result of which their short-range order is destroyed, after which the short-range order can be re-combined during pulse pauses or externally to the heat generator (1), thereby releasing or generating thermal energy.