In vapor compression refrigeration, I know how to calculate the work done by the compressor (enthalpy at outlet - enthalpy at inlet), but I am lost on how to calculate the work done by the evaporator, condenser, and the expansion valve. For the evaporator and condenser, if I wish to have a certain amount of heat exchange occur between the refrigerant and the air, would I just need to calculate the flow rate needed to attain the right amount of convection and get how much work needs to be done by the fan to generate that much air flow? If not, what should I do? For the expansion valve, however, I don't know where to get started. Thank you for the help in advance.