what is a heat pump, how does it work?
It works on the basis of second law of termodynamics , which states heat can be transferred from a source at lower temperature to a sink of higher temperature , if work is done on the system. It is just like a refrigeration system. A refrigeration system works like this: Source-----Q1------> Work by compressor ---------Q2---->Sink The heat Q1 is removed from the system making a space cooler and discharging the heat to the atmosphere when work is applied through a compression system However if you see a heat pump, it is on the same principle, the only difference is that the sink becomes the heated area and the source becomes the atmosphere , that is why it is called a heat pump, the source is atmosphere and the sink is conditioned heated room area in this case!
A heat pump works just like a refrigerator except it runs in reverse. The heat pump has a coil outside for house where the Freon is allowed to evaporate. Then the Freon gas is pumped into your house where it is converted to a gas and in so doing, gives off heat.Then the Freon goes back outside to evaporate again. It is a closed system, like a fridge. It works best it the outside coil is set in water ( not ice) rather than in open air.This is because cold air does not have much energy in it that you can take out.
A heat pump is a machine or device that moves heat from one location (the 'source') to another location (the 'sink' or 'heat sink') using mechanical work. Most heat pump technology moves heat from a low temperature heat source to a higher temperature heat sink. Common examples are food refrigerators and freezers, air conditioners, and reversible-cycle heat pumps for providing thermal comfort. Heat pumps can also operate in reverse, producing heat. This produces an efficient way of drying, and manufacturers such as Panasonic, Toshiba, AEG and Miele have released tumble dryers or washing dryers that utilise this method. It is claimed to be more energy saving and quicker than conventional drying. Heat pumps can be thought of as a heat engine which is operating in reverse. One common type of heat pump works by exploiting the physical properties of an evaporating and condensing fluid known as a refrigerant. In heating, ventilation, and cooling (HVAC) applications, a heat pump normally refers to a vapor-compression refrigeration device that includes a reversing valve and optimized heat exchangers so that the direction of heat flow may be reversed. Most commonly, heat pumps draw heat from the air or from the ground. Air-source heat pumps do not work well when temperatures fall below around ?5°C (23°F).
