In　this　study,　the　defrosting　system　of　an　air　source　heat　pump　utilizing　compressor　casing　heat　storage　combined　with　a　hot　gas　bypass　cycle　(ASHP-CCHS-HGBC)　was　designed.　The　phase　change　material　for　defrosting　was　selected,　the　phase　change　heat　storage　exchanger　was　devised,　and　the　ASHP-CCHS-HGBC　test　system　was　established.　The　power　consumption,　defrosting　time,　and　the　influence　of　the　indoor　exchanger　outlet　on　the　air　temperature　in　the　ASHP-CCHS-HGBC　method　were　then　compared　with　those　of　the　reverse-cycle　defrosting　(RCD)　and　electric　heating　defrosting　(EHD)　methods.　Experimental　results　reveal　that　the　total　defrosting　time　and　consumption　of　the　ASHP-CCHS-HGBC　method　was　100　s　and　43.6　kJ,　respectively.　These　values　were　lower　by　10　s　(9%)　and　12.1　kJ　(21.7%)　relative　to　those　of　RCD.　Moreover,　the　compressor　suction　temperature　was　increased　by　10.1　degrees　C　during　defrosting　by　ASHP-CCHS-HGBC.　Under　the　normal　heating　operation　for　2.5　h,　10　L　hot　water　with　a　temperature　of　30　degrees　C　was　obtained,　the　compressor　casing　temperature　was　reduced　by　4.6　degrees　C.　While　defrosting,　the　air　temperature　of　the　indoor　heat　exchanger　outlet　declined　to　only　3.3　degrees　C　and　exerted　the　least　influence　on　the　indoor　temperature　among　those　of　the　three　defrosting　methods.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.