Orc for transforming waste heat from a heat source into mechanical energy and cooling system making use of such an orc

Abstract

ORC (Organic Rankine Cycle) for transforming heat from a heat source (11) into mechanical energy, the ORC (8) comprising a closed circuit (14) containing a two-phase working fluid, the circuit (14) comprising a liquid pump (15) for circulating the working fluid in the circuit (14) consecutively through an evaporator (10) which is configured to be placed in thermal contact with said heat source (11); an expander (12) for transforming the thermal energy of the working fluid into mechanical energy; and a condenser (16) which is in thermal contact with a cooling element (17), characterized, in that the expander (12) is situated above the evaporator (10) and in that the fluid outlet (22) of the evaporator (10) is connected to the fluid inlet (23) of the expander (12) by means of a so called raiser column (24) which is filled with a mixture of liquid working fluid and of gaseous bubbles of the working fluid, wherein the mixture is supplied to the expander (12) and the raiser column (24) extends with at least a part at the same level or above the level of the inlet (23) of the expander (12) in such a way that gravitational flow of the liquid working fluid supplied by the raiser column (24) to the expander (12) is possible.

Description

technical field [0001] The present invention relates to ORCs for converting waste heat from heat sources into mechanical energy, and to cooling systems utilizing such ORCs to cool waste heat sources. Background technique [0002] Thermodynamic cycles for WTP (Waste Thermal Power) are well known, such as ORC cycle, Kalina cycle, Trilateral Flash cycle, and the like. [0003] These thermodynamic cycles are designed to recover waste heat from a heat source and convert the thermal energy into useful mechanical energy that can be used, for example, to drive a generator to generate electricity. [0004] In particular, it is known to use ORC (Organic Rankine Cycle) to recover waste heat energy of a relatively low-temperature heat source, such as heat of compressed gas generated by a compressor device, or heat contained in exhaust gas, flue gas, steam, hot water, etc. . [0005] This known ORC comprises a closed-loop circuit containing a two-phase working fluid, the closed-loop ci...

AI Technical Summary

Problems solved by technology

[0007] A disadvantage of existing ORCs is that the size of the evaporator must be relatively large in order to have sufficient heat transfer contact between the working fluid in the evaporator and a heat source, especially a low temperature heat source such as 90°C or even 60°C, and The contact surface between the liquid components of the working fluid to be evaporated in the evaporator is only a small fraction of the total contact surface of the evaporator, since the evaporator only contains the liquid at the bottom and the vapor of the working fluid at its top

[0008] Another disadvantage is that in the event of liquid pump or expander failure, the circulation of the working fluid in the ORC is automatically terminated, since the evaporator needs to be located above the expander in order for the liquid component of the working fluid to gravity flow from the evaporator to the expander , especially when a two-phase fluid is preferably supplied to the expander inlet

[0011] The disadvantage is that an auxiliary cooler must be provided

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