Proper and sufficient duct air flow is the determining factor for longevity of a heat pump. It is also the area that requires the most planning. As an electrical engineer, you are familiar with the motor power formula and the concept of resistance to electrical flow in wire diameters and lengths. Duct air flow design requires similar formulae. Given your ability to study to complete engineering design, it is possible for you to verify that the resultant air flow will provide the proper environment for the operation of your heat pump without excessive internal pressures and resultant amperage draws.
The other concern is that of making sure the system is installed to give the expected design life. The factory HVAC engineers require the equipment be installed by experienced, licensed technicians so there is a reasonable expectation thet the equipment will reach its design lifetime. The field of study that is missing from electrical engineering is the study of physics concerning gas laws and thermodynamics. While the mechanical assembly of sheetmetal and electrical conections is not difficult, proper creation of a sealed system to prevent loss of environmentally damaging chemicals while not contaminating the unit through inexperience with fluxes and brazing techniques without damaging the copper lines is more akin to nuclear plant installation than silicon doping and electroplating.