EcoCute

The EcoCute is an energy efficient electric heat pump, water heating and supply system that uses heat extracted from the air to heat water for domestic, industrial and commercial use. Instead of the more conventional ammonia or haloalkane gases, EcoCute uses supercritical carbon dioxide as a refrigerant. The technology offers a means of energy conservation and reduces the emission of greenhouse gas.

The name of the EcoCute comes from the Japanese phrase Shizen Reibai Hīto Ponpu Kyūtō-ki (自然冷媒ヒートポンプ給湯機^?), which literally means "natural refrigerant heat pump water heater".Eco is a contraction of either ecology or economical and Cute is a near homonym to kyūtō (給湯^?); literally “supply hot water.”

Modern chemical refrigeration techniques developed after the proposal of the Carnot cycle in 1824. Jacob Perkins invented an ice-making machine that used ether in 1843, and built a refrigerator that used water and sulfuric acid in 1850. In Japan, Fusanosuke Kuhara, founder of Hitachi, Ltd., made an air conditioner for his own home use using compressed CO₂ as a refrigerant.

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