1. Think Green

Both sustainable energy and renewable energy are important issues related to energy efficiency. While renewable energy originates from natural resources, sustainable energy can be achieved through improved energy efficiency. To care for our globe, it is desirable to use renewable sources to supply sustainable energy. Air is the most popular source of renewable energy. Based on the physical characteristics of energy transfer, heat pump uses renewable energy as energy source with power input to drive compressor to generate useful energy via refrigeration cycle. Utilizing the refrigeration cycle, heat pump absorbs energy from renewable source to provide heating/cooling for buildings. With increasing concern on environmental quality, the concept of green building (or called sustainable building) attracts attention from various perspectives. Green building is the practice of reducing the negative environmental impacts of buildings and enhancing the health and well-being of building occupants. Energy efficiency and renewable energy are core components of green building.