Aliyense amadziwa kuti chakudya chosiyidwa mukutentha kwachangu mofulumira kuposa momwe chimachokera kukazizira. Pansi pa kutentha kwakukulu, mabakiteriya amachepetsa ntchito zawo, ndipo zakudya zozizira zimakhala zotalika kuposa firiji. Ngakhale m'masiku akale, anthu ankawona kuti katundu amene watsala mumthunzi amakhalabe wautali kuposa omwe amaima padzuwa. Komanso, anthu adawona kuti m'nyengo yozizira, maulendo a zowonjezera amawonjezeka nthawi zambiri. Choncho, anayamba kufunafuna njira zothetsera vuto la kusungirako mankhwala ndi kutentha.
Zina zimakumba pansi, chifukwa kutentha kwa pansi kumakhala kochepa kwambiri, zina zimagwiritsa ntchito mazira kapena chisanu. Ngakhale ndi nyengo yotentha ya m'chipululu, anthu usiku analikuzira madzi omwe ankasungira chakudya cha tsikulo. Njira zonsezi zinali zochepa kwambiri kuteteza zinthu za firiji zamakono, zomwe zinawonekera zaka zambiri pambuyo pake.
Bambo wamkulu wakale wa firiji wamakono anamasulidwa pa August 17, 1816, koma adalibe kugwiritsa ntchito pakhomo. Zida za firiji zinayambira ku US mu 1925, ndipo mu USSR nkhaniyi ya zipangizo zapanyumba zinayamba kupezeka kwa anthu kuyambira m'ma 1960 okha. Mafiriji a Soviet anali ovuta komanso osagwira ntchito, koma odalirika komanso osasunga.
Kuchokera nthawi imeneyo, firiji yasintha nthawi zambiri. Kusintha kowonjezereka kapangidwe ndi makhalidwe apamwamba. Mpaka pano, chisankho chawo ndi chachikulu kwambiri moti anthu ambiri amadabwa kuti ndigugu liti lomwe lingagule. Tsopano ndizotheka kusankha firiji kuti mukhale ndi zokoma zilizonse, zoyenera mkati mwa khitchini mu mtundu kapena kukula, komanso m'kalasi la kupulumutsa mphamvu ndi kutentha. Mafiriji amasiku ano amabwera mu mitundu iwiri, kumira ndi kuuma. Zoyamba ndizo firiji zomwe zimafuna nthawi zonse zotsutsana, zina sizikufuna njirayi.
Mchitidwe wa chisanu chakuda unawoneka posachedwapa. Nthawi zambiri anthu amamva mawu otchuka akuti "dziwani chisanu", chomwe aliyense amakhudzana ndi nthawi yozizira kwambiri. Ngakhale mu Chingerezi mawu awa amveka - palibe chisanu. Mu firijiyi, evaporator amabisika kumbuyo kwa khoma kapena pamwamba pafriji ndipo amodzi kapena ambiri mafani amapezeka nthawi zonse kuti azizizira mpweya wozizira, womwe umalowa m'zipinda kudzera muzipangizo zapadera. Pamene firiji imagwira ntchito, chinyezi chimapezeka, chomwe sichikhazikika pa khoma la chipinda chokhala ndi chisanu, koma chimaphimba mbali yozizira kwambiri ya evaporator. Compressor imachotsedwa nthawi ndi nthawi ndipo nthawi yomwe imayambidwa, imachotsedwa ndi kanyumba kakang'ono koyambirira, ndipo chinyontho chimapangika.
Pali zambiri zabodza zokhudza ubwino ndi kuopsa kwa chisanu chouma. Koma mfundo yakuti dongosolo loterolo likugwiritsidwa ntchito ndi lonse la Europe likulankhula lokha. Firijiyi sayenera kukhala thawed, koma anthu ambiri omwe amagwiritsa ntchito izo, ndi opanga okha amalimbikitsa kamodzi pachaka, firiji imatsutsabe kuti ikhale yotalika. Zomwe zimagwiritsidwa ntchito m'mafiriji oterewa zimakhazikika mofulumira komanso mofanana, zimamanganso, zomwe zimateteza mtundu wawo, kulawa, mavitamini komanso minerals. Mitundu yonse ya zipatso, amadyera, nsomba ndi nyama, ndiwo zamasamba zowonjezera chisanu chouma. Chinthu chachikulu sikuti awononge chakudya kachiwiri, atatha kutaya. Njira iyi yosungira zinthuzi ndizosavuta komanso zothandiza kuposa kung'amba, chifukwa zimasungira katundu popanda kuwonjezera zowononga zoipa ngati vinyo wosasa, mwachitsanzo, zomwe zimakhudza thupi la munthu sizikusowa umboni.
Ambiri amanena kuti firiji ndi dongosolo "amadziwa chisanu" ndi phokoso kwambiri chifukwa cha ntchito ya mafani. Mawu awa sagwiritsidwa ntchito kwa mitundu yonse. Okonza ena amagwiritsa ntchito mafani omwe amakhala chete mwakachetechete, komabe, zitsanzozi ndi zodula pang'ono. Vuto lina la firiji ndi mazira ozizira ndi kuti chakudya chouma kwambiri kuti chipewe ichi, muyenera kukulunga bwino mafilimu a pulasitiki. Mafiriji okhala ndi zowuma amawononga mphamvu zambiri kuposa mafiriji okhala ndi dontho.
Mwinamwake, izi zonse zimadziwika zolephera za kuzizira. Koma nthawi zonse mudzakhala ndi mwayi kudabwa alendo mu chaka chatsopano ndi atsopano strawberries anasonkhana ndi munda wawo m'munda wawo.