Design Solutions for the Main Heat Exchangers in the Organic Rankine Cycle Circuit (Review)

The results are presented of the search for and systematization of information on typical design solutions for the main heat exchangers of installations with low-boiling working fluids. The organic Rankine cycle (ORC) has been widely accepted as a way for converting waste (exhaust) heat into electrical energy. An increase in the installed capacity of operating commercial ORC power plants and their total capacity is noted in the world every year. At the same time, design options for the main heat exchangers (heater, evaporator-superheater, condenser, regenerative heat exchanger) are not available in open access and presented in catalogues: information about them is not disclosed by the manufacturers and information available in publications is limited and disembodied. An attempt is made in this paper to systematize the available information and, based on an analysis of world and domestic experience in industrial production, formulate an idea of potential engineering solutions for heat and mass transfer installations, which can be offered as prototypes of the considered apparatuses. At the same time, the search for such solutions was focused primarily on apparatuses used in the refrigeration industry, conventional steam turbine power units, and modern ventilation and air-conditioning systems. The advantages and disadvantages of such apparatuses are examined. The results are presented of a comparative analysis of their design, power range, operational features, and the potential effect of these factors on the operation of the overall ORC installation. Approaches to the selection of heat-exchange equipment for ORC installations given in the available publications and proven in practice have been investigated and described.