Individual Procedures in a Cycle | ||
Compression - Condensation - Release - Evaporation, demonstrated by common examples | 
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Changing from low pressure to high pressure: Air compression with a closed air pump - compressor If the pump volume is compressed by piston movement while the outlet valve is closed, this corresponds to the action of a compressor. And if the action is repeated several times, the result is not only compression but also heat, partly generated by friction. Changing from gaseous phase to liquid: Boiling spaghetti - condenser When boiling spagetti or noodles you first boil water in a pot, with the lid closed, before you add the noodles. When you lift the lid, steam escapes, which condenses on your skin and may even cause burn injuries, since the heat of the steam is combined with high temperatures, a result of the released condensation energy. This common practical example shows that condensation produces a lot of energy in form of heat. This energy is the total of steam energy and condensation energy. Changing from high pressureto low pressure: Gas bottle with escaping gas - release valve A gas bottle used for heating a construction site, for example, soon forms a layer of ice on the surface of the gas bottle; this is a clear indication for the temperature drop. Further there is a drop in pressure since after a while, the gas bottle looses its overpressure and eventually is empty. Changing fromliquid to gasesous state: Shivering at the pool in spite of high outside temperatures - evaporator If you leave the pool at a water temperature of 20°C (68°F) and go for your towel, you feel a chill and get goose pumps in the slightest breeze, although the air temperature is 30°C (86°F). The water evaporates on the skin and withdraws heat - the result is latent heat loss. Conclusion: The heat pump "transforms" heat from a lower thermal level to heat of a higher thermal level. Thereby the heat pump uses temperature changes, as well as the high-energy state changes from gaseous to liquid and vice versa, which we commonly from daily routines! |
