To　meet　the　simultaneous　needs　of　high　temperature　disinfection　and　freezing　in　the　field　of　food　processing,　a　new　concept　of　combined　heating　and　cooling　transcritical　CO2　system　integrated　with　dedicated　mechanical　subcooling　utilizing　hydrocarbon　mixture　is　proposed.　The　system　performance　in　terms　of　thermodynamics,　economy　and　environment　is　studied　and　compared　with　the　baseline　combined　heating　and　cooling　transcritical　CO2　system　and　four　traditional　combined　heating　and　cooling　solutions,　considering　the　influence　of　temperature　glide　and　the　heat　transfer　deterioration.　The　new　proposed　system　is　further　optimized　by　using　the　machine　learning　method　of　artificial　neural　network　and　non-dominated　sorting　genetic　algorithm.　Multi-objective　optimization　is　conducted　considering　the　objective　function　of　energy　efficiency,　initial　capital　cost　and　life　cycle　carbon　emissions　of　the　new　system,　to　obtain　the　optimum　components　and　concentration　ratio　of　the　hydrocarbon　mixture.　The　results　indicate　the　thermodynamic　performance　and　environmental　benefits　of　subcooling　subsystem　with　hydrocarbon　mixture　are　better　than　those　of　the　pure　system.　In　contrast　to　that　using　pure　R290　and　R601,　the　coefficient　of　performance　is　enhanced　by　8.20　%　and　8.13　%　and　the　life　cycle　carbon　emission　is　reduced　by　8.54　%　and　9.31　%,　respectively,　when　R290/R601　(50/50)　is　used.　However,　the　initial　capital　cost　is　9.25　%　and　10.23　%　higher　than　that　of　pure　R290　and　R601,　respectively.　Finally,　the　hydrocarbon　mixture　corresponding　to　the　optimal　design　point　is　R1270/R601a　(53/47),　the　corresponding　discharge　pressure　is　12.86　MPa,　and　the　subcooling　degree　is　37.50　degrees　C.　This　study　can　provide　a　theoretical　reference　for　the　application　of　CO2　refrigeration　and　heat　pump　technology.