Abstract: Provided is an aluminum coated steel sheet having excellent oxidation and heat resistance. The aluminum coated steel sheet includes an aluminum coating layer and an alloy layer. The aluminum coating layer is formed on a surface of a steel sheet which includes 0.001 to 0.015 wt % of carbon (C), 0.05 to 0.3 wt % of silicon (Si), 0.1 to 0.6 wt % of manganese (Mn), 0.01 to 0.05 wt % niobium (Nb), 0.01 wt % or less of phosphorus (P), 0.01 wt % or less of sulfur (S), 0.1 wt % or less of soluble aluminum (Al), 0.05 to 0.5 wt % of copper (Cu), 0.05 to 0.5 wt % nickel (Ni), 0.001 to 0.01 wt % of nitrogen (N), and the balance of Fe and inevitable impurities. The alloy layer includes an intermetallic compound at an interface between the steel sheet and the aluminum coating layer.

Abstract: Provided is an aluminum coated steel sheet having excellent oxidation and heat resistance. The aluminum coated steel sheet includes an aluminum coating layer and an alloy layer. The aluminum coating layer is formed on a surface of a steel sheet which includes 0.001 to 0.015 wt % of carbon (C), 0.05 to 0.3 wt % of silicon (Si), 0.1 to 0.6 wt % of manganese (Mn), 0.01 to 0.05 wt % niobium (Nb), 0.01 wt % or less of phosphorus (P), 0.01 wt % or less of sulfur (S), 0.1 wt % or less of soluble aluminum (Al), 0.05 to 0.5 wt % of copper (Cu), 0.05 to 0.5 wt % nickel (Ni), 0.001 to 0.01 wt % of nitrogen (N), and the balance of Fe and inevitable impurities. The alloy layer includes an intermetallic compound at an interface between the steel sheet and the aluminum coating layer.

Abstract: A heat pump that uses solar heat as an evaporation heat source of a refrigerant. The heat pump includes a solar heat collector, a compressor to compress a refrigerant, a first heat exchanger to condense the refrigerant compressed by the compressor and to perform heat exchange between the condensed refrigerant and water, a second heat exchanger to perform heat exchange between the refrigerant having passed through the first heat exchanger and heat collected by the solar heat collector, a third heat exchanger to perform heat exchange between the refrigerant having passed through the first heat exchanger and external air, and a first flow channel switching valve to allow the refrigerant having passed through the first heat exchanger to selectively flow to the second heat exchanger or the third heat exchanger therethrough.