HISTORY OF REFRIGERATOR

arnabkiut

Before mechanical refrigeration systems were introduced, People cooled their food with ice and snow, either found locally or brought down from the mountains. The first cellars were holes dug into the ground and lined with wood or straw and packed with snow and ice: this was the only means of refrigeration for most of history. [size=-1]Refrigeration is the process of removing heat from an enclosed space, or from a substance, to lower its temperature. A refrigerator uses the evaporation of a liquid to absorb heat. The liquid, or refrigerant, used in a refrigerator evaporates at an extremely low temperature, creating freezing temperatures inside the refrigerator. It's all based on the following physics: - a liquid is rapidly vaporized (through compression) - the quickly expanding vapor requires kinetic energy and draws the energy needed from the immediate area - which loses energy and becomes cooler. Cooling caused by the rapid expansion of gases is the primary means of refrigeration today. [size=-1]The first known artificial refrigeration was demonstrated by William Cullen at the University of Glasgow in 1748. However, he did not use his discovery for any practical purpose. In 1805, an American inventor, Oliver Evans, designed the first refrigeration machine. The first practical refrigerating machine was built by Jacob Perkins in 1834; it used ether in a vapor compression cycle. An American physician, John Gorrie, built a refrigerator based on Oliver Evans' design in 1844 to make ice to cool the air for his yellow fever patients. German engineer Carl von Linden, patented not a refrigerator but the process of liquifying gas in 1876 that is part of basic refrigeration technology.

winamp05

no reply ?

edmundo

Ade tertengok filem Kingdom of Heaven masa Panglima Saladin balik ke camp tentera Islam, anggota beliau ade bg ais batu masuk dlm minuman..

Tk pasti how true was it during that time sbb dh ade simpanan air batu.. Klu7 betul ade, mmg respeklah sbb time tu kn dkt pdg pasir.

naen

3# edmundo

mungkin ..

cuba search : YAKHCHAL

A yakh-chāl (meaning "ice pit") is an ancient type of refrigerator.

Above ground, the structure had a domed shape, but had a subterranean storage space; it was often used to store ice, but sometimes was used to store food as well. The subterranean space coupled with the thickheat-resistant construction material insulated the storage space yearround. These structures were mainly built and used in Persia. Many remain standing that were built hundreds of years ago.

In 400 BC Iran, Persian engineers had already mastered the technique of storing ice in the middle of summer in the desert. The ice was brought in during the winters from nearby mountains in bulk amounts, and stored in a specially designed, passively cooled refrigerator, called a yakhchal (meaning ice pit). This was a large underground space (up to5000 m³ ) that had thick walls (at least two meters at the base) made out of a special mortar called sārooj, composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions, and which was resistant to heat transfer. This mixture was thought to be completely water impenetrable. The space often had access to a Qanat, and often contained a system of windcatchers that could easily bring temperatures inside the space down to frigid levels in summer days. The ice was then used to chill treats forroyalty during hot summer days and to make faloodeh, the traditional Persian frozen dessert.

+ marco polo pernah mention pasal benda yakhchal ni

sayapghaib

Penduduk dikawasan pedalaman pada tahun 1980an menggunakan minyak tanah untuk menjana peti sejuk mereka.Ada sesapa kat sini yang tau cara tersebut tak?.Minyak tanah tersebut bukan menjana generator elektrik tapi menjana terus power peti sejuk tersebut.

HangPC2

aku susah nak sebut      re fi ge ra tor

naen

5# sayapghaib

haba -> wap -> cecair (terhasil daripada wap) -> sejuk

tak reti nak terangkan camne, tapi mungkin bleh search pasal propane refrigerator ..

ni ada sikit hasil search : http://www.howstuffworks.com/refrigerator5.htm
dengan yg ni (ada gambarajah) : http://www.gasrefrigerators.com/howitworks.htm

esbok propane ni masih ada digunakan kat US & rasanya china pun ada keluarkan esbok ni

Sarahmoluccan

The really old fridges required an iceman to deliver ice....I would not go with an older Refrigerator. I hated all of the wasted space. I would get a fridge with rounded corners and be done with it.

supernaturalee

Suruh je elsa let it go
Dh keluar pun ais