Keilini Portable Heater for Indoor Use from caroly nentz's blog

The warm water from your Keilini Portable Heater  boiler flows through a radiator coil and an electric fan pushes air thru the radiator coil. The air coming into the coil absorbs the heat from the water, resulting in a warmer discharge air temperature. The cooler water leaving the coil returns back to the boiler to be reheated for every other pass via the radiator coil.https://www.healthmassive.com/keilini-portable-heater/