低品位余热利用技术的研究现状、困境和新策略

 能源是经济发展和社会进步的重要基础，在能源消耗不断攀升从而带来诸多社会和环境问题的现实背景下，节能减排已成为当今人类的共识。低品位余热利用作为节能减排中的重要部分，具有巨大的发展潜力。但当前技术中固有的材料性能、封装工艺、换热器性能等障碍，在一定程度上阻碍了它的进一步发展。本文针对这一事实，评估了国内外在低品位余热利用方面的研究态势，特别就热能传递与利用的关键环节进行了深入剖析。在此基础上，提出要充分利用室温金属流体优异的传热性能和低功耗驱动特性，部分取代传统工业余热利用过程中通常采用的水冷介质，以发展新一代高效余热利用和发电装备。阐述了无水换热器的概念，并提炼出其中的关键科学技术问题。随着室温金属流体换热器技术的研究深入，可望引申出一个全新的工业余热应用领域，相应研究必将对节能、节水和降耗，以及环境保护等方面带来深远的影响。

Current Research Status,Difficulties and New Strategy in Utilization of Low Grade Heat

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.