Today, however, crucial words used to describe these traditional topics have been stripped from an influential children's dictionary in favour of more 'modern' terms. Among the entries which have disappeared from the latest edition of the Oxford Junior Dictionary are disciple, coronation, empire, piglet and acorn. In their place come the likes of MP3 player, broadband, biodegradable, committee and celebrity.
A heat pump is a device that transfers heat energy from a source of heat to a destination called a heat sink. Heat pumps are designed to move thermal energy in the opposite direction of spontaneous heat transfer by absorbing heat from a cold space and releasing it to a warmer one. A heat pump uses a small amount of external power to accomplish the work of transferring energy from the heat source to the heat sink.
pump (circulator) on a hot water heating system has the same function as the fan on a forced air heating system. We are pushing the heat transfer medium (water) from the boiler out to the rooms we want to heat. Just like the fan on a forced air system, the pump pushes the heated water out to the system and pulls the cool water back.