Edited sentence: Bodies with large temperature differences transfer heat faster than bodies with lower temperature differences.Fluid, usually water, in the absorber tubes collect the trapped heat and transfer it to a heat storage vault.Heat and infrared radiation (IR) are produced when short wave radiation light hits the absorber plate, which is then trapped inside the collector.Heat gain is the heat accumulated from the sun in the system.Heat in a solar thermal system is guided by five basic principles: heat gain; heat transfer; heat storage; heat transport; and heat insulation.Heat insulation is vital in both heat transport tubing as well as the storage vault.Heat is transferred either by conduction or convection.Heat is transferred from the absorber plates of the collector in the fluid by conduction.Heat is transferred to a thermal storage medium in an insulated reservoir during hours with sunlight, and is withdrawn for power generation during hours lacking sunlight.Heat storage enables solar thermal plants to produce electricity during hours without sunlight.Heat transport refers to the activity in which heat from a solar collector is transported to the heat storage vault.Here, heat is the measure of the amount of thermal energy an object contains and is the product of temperature and mass.Inside the vault, heat is transferred throughout the medium through convection.It prevents heat loss, which in turn relates to energy loss, or decrease in the efficiency of the system.Rate of heat transfer is related to the conductive and convection medium as well as the temperature differences.Solar thermal heat is trapped using the greenhouse effect; the greenhouse effect in this case is the ability of a reflective surface to transmit short wave radiation and reflect long wave radiation.The collector fluid is circulated through the carrier pies to the heat transfer vault.The distribution of energy from the rising hot water to the sinking cold water contributes to the convection process.Thermal storage mediums will be discussed in a heat storage section.These molecules spread their thermal energy by conduction and occupy more space than the cold slow moving molecules above them.When water is heated, kinetic energy is transferred by conduction to water molecules throughout the medium