Modes of Heat Transfer This post is the third part of the complete Heating Ventilation and Air Conditioning. We will Study Heating Ventilation and Air Conditioning from Basic to Advance level. So, Let's Start.. Modes of Heat Transfer : Following are the three types of mode of Heat transfer. * Conduction. * Convection. and * Radiation. Conduction : It is the mode of heat transfer through solid materials. Convection : It is the mode of heat transfer through liquid substances. Radiation : It is the mode of heat transfer without any medium, for example, vacuum. Enthalpy : It is the amount of inside energy and result of pressure and volume.. This sum "U+PV" is known as "Enthalpy (H)". H = U + PV (or) Heat content of a body is called as Enthalpy. The units of Enthalpy are kJ / hr, Btu / hr etc. Humidity : ...