[Editor's note:This first installment of a two-part series looks at the characteristics of CO2.]
Carbon dioxide (CO2) is not new to refrigeration systems. Alexander Twining proposed using CO2 as a refrigerant in a British patent granted him in 1850. Thaddeus S.C. Lowe, perhaps best known for his experimentation with CO2 military balloons, designed an ice machine using CO2 in 1867. Lowe also developed a machine for marine transportation of frozen meat.