Introduction to heat pumps

The natural direction of heat transfer flow is from a region of high temperature to another with lower temperature. Heat can be “pumped” from the low to the high temperature region using a device called heat pump, which needs mechanical or electrical energy to run. Heat pumps are considered as efficient energy systems and used for various heating applications such as; space heating, domestic hot water, swimming pools heating, drying, industrial applications, etc. Refrigeration and air conditioning systems are also in principle heat pumps where in this case the purpose is to provide cooling; i.e. pumping heat from the refrigerated space to a high temperature heat sink, where heat is dumped.

In this lecture, I will give introduction to the principle of heat pumps, explain the different types, discuss the conditions for efficient application, and compare the energy savings with heat pumps to the most common alternatives for space heating.