Abstract：Energy is an important factor in the economic and social progress of human society. Facing social and environmental problems induced by increasing energy consumption, the energy conservation and emission reduction becomes a consensus. As an important component of energy technology, the low-grade waste heat recovery technique has a great potential. However, the current techniques suffer from a number of difficulties, such as the poor performance of materials, the low level of encapsulation techniques, and the limitation of heat exchangers, which hampers its progress to some extent. This paper reviews the domestic and international researches on the utilization of low-grade waste heat, especially, the key links between heat transfer and utilization. Based on the assessment of the current techniques, the application of room temperature liquid metals is proposed, for their excellent heat transfer performance and low power driving property, to partly replace water, as is usually adopted in the conventional waste heat recovery process. In this way, a new generation device with high efficiency in recovery of waste heat and power generation can be developed. The concept of water free heat exchanger is discussed, together with the key scientific and technological issues. With the development of the liquid metal heat exchanger technology, it is expected that a new field of utilizing industrial waste heat would emerge, which would bring about deep impact in many respects such as energy and water conservation, energy consumption reduction and environmental protection.