An air conditioning and heat pump system includes a multi-communicative valve unit, a compressor unit connected to the multi-communicative valve unit, an evaporator unit connected to the multi-communicative valve unit, a heat exchanger connected to multi-communicative valve unit, a water heater connected to the compressor unit and the multi-communicative valve unit, and an evaporative cooling system which comprises at least one multiple-effect evaporative condenser for effectively cooling the working fluid. The air conditioning and heat pump system is selectively operated in one of an air conditioning mode, a heat pump mode, a water heater mode, and a defrosting mode, and can be switched such that the working fluid can either be cooled by the evaporator unit or and evaporative cooling system.