Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
Christian Steenstrup
Christian Steenstrup (December 2, 1873 – November 28, 1955) was a Danish inventor who invented the hermetically sealed refrigeration unit while Chief Engineer at General Electric, and held over 100 patents.
His improvement to the refrigerator sent the sales of the G.E. Monitor Top refrigerator soaring.
Streenstrup immigrated to the US in 1894.