Gabaɗaya, ma'ajiyar sanyi ana sanyaya ta injinan firji, ta amfani da ruwa mai ƙarancin zafi mai zafi (ammoniya ko Freon) azaman masu sanyaya. Wadannan ruwaye suna ƙafe a ƙarƙashin ƙananan matsi da yanayin sarrafawa na inji, suna ɗaukar zafi a cikin ɗakin ajiya, don haka cimma manufar sanyaya da rage zafin jiki.
Firinji mai nau'in matsawa ya zama ruwan dare, wanda galibi ya ƙunshi kwampreso, na'ura mai ɗaukar nauyi, bawul ɗin magudanar ruwa, da bututu mai fitar da iska. Dangane da yadda ake shigar da bututun mai, ana iya raba shi zuwa sanyaya kai tsaye da sanyaya kai tsaye. Sanyaya kai tsaye yana shigar da bututun ƙafe a cikin ɗakin ajiyar sanyi, inda mai sanyaya ruwa kai tsaye yana ɗaukar zafin da ke cikin ɗakin ta cikin bututun fitar da iska kuma yana sanyaya. na'urar. Iskar, bayan an sanyaya ta da bututun fitar da ruwa a cikin na'urar sanyaya, ana mayar da shi cikin dakin don rage zafi.
Amfanin hanyar sanyaya iska ita ce ta yi sanyi da sauri, yanayin zafi a ɗakin ajiya ya fi iri ɗaya, kuma yana iya kawar da iskar gas mai cutarwa kamar carbon dioxide da ake samarwa yayin aikin ajiya.