The invention provides an air conditioner, a
defrosting control method and a
defrosting control system. The air conditioner comprises a compressor, an indoor
heat exchanger, an outdoor
heat exchanger, a four-way valve, a throttling device, a heat accumulating
assembly and a stop valve, wherein the heat accumulating
assembly is arranged between the four-way valve and the outdoor
heat exchanger, comprises a heat accumulator, a water feeding device, an
electric heating piece, a first temperature detecting device and a second temperature detecting device; and the stop valve is arranged between the four-way valve and the outdoor heat exchanger, and is connected in parallel with the heat accumulating
assembly. According to the air conditioner disclosed by the invention, the heat accumulating assembly enables the air conditioner to perform
defrosting under a heating mode, so that the favorable defrosting effect and the favorable
heating effect are guaranteed, and the usage comfort of users is improved; when heat accumulating materials are short of water and the defrosting effect is poor, the water can be supplied by the water feeding device, and the four-way valve is switched, so that the air conditioner performs defrosting under a
refrigeration mode, and the favorable defrosting effect is guaranteed; and after
water supply is completed, the four-way valve is switched, so that the air conditioner performs defrosting under the heating mode, and the usage comfort of the users is improved.