This book presents a comprehensive review of energy research studies from authors around the globe, including recent research in determining potential energy and environmental impacts; sustainable development and environmentally friendly systems; helping agriculture and horticulture through technology, energy efficiency and environmental protection; clean and green energy technologies; heat pump features, characteristics and refrigerants; a passive system for energy needs in green houses; design and operation of low consumption passive human comfort solutions; and the pretreatment of cellulosic biomass for better yield of bioethanol production.