Heat Pump - thermodynamics:

Heat Pump: Heat pump is reversed heat engine that removes heat from a body at low temperature and transfer heat to the body at higher temperature. It receive heat Q₂ from atmosphere at the temperature T₂  equal to atmospheric temperature.

temperature to higher temperature. It supplies heat Q₁ to space to be heated at the temperature T₁.

Performance of HP:  It is measured by coefficient of performance (COP). This is ratio of amount of heat rejected by the system to mechanical work received by the system.

(COP)HP  = Q₁/W = Q₁/(Q₁  - Q₂)  = T₁/ (T₁  - T₂)