Dear all
Based on what I read in different articles, adding recuprator does not affect the delta P over the expander (turbine), however it reduces the condensation pressure and temperature ( due to pressure drop over the recuprator unit). It also can reduce the heat load on preheater which will improve the total efficiency of the cycle. I understood it as it can reduce the total heat load needed to produce the same amount of electrical power.
However another colleague says it affects the power output by reducing the heatload and pressure of condenser which in turn reduces the pressure output of the expander ( basically dictates expander to operate within larger pressure difference) and this is why it can let the cycle produce more power with less heat input.
Which analysis is the correct one? could you please motivate your answer.
Thanks for your article Vitalii, but that table only presents the final results. I would like to see how the cycle diagram looks like on T-S diagram. Do you have any information on that?
Upper and lower pressures of cycle is a design parameter and they can not be changed so you should optimize other parameter in cycle emphsises mass flow rate of coolant fluid.....
Both scenarios are correct.
Recuprator, recovers some part of heat which should be wasted in condenser (when we do not use this heat anywhere else). Your explanations on pressure drop is, also, correct.
But, the important point is that recuprator (heat regeneration) is useful in case of high temperature heat resources. For the low temperature heat resources, it is not economically a good option.
For T-S diagram, please look at figure 6: https://www.sciencedirect.com/science/article/pii/S1359431115012375
Introducing an internal heat exchanger (IHE) in an ORC does not necessarily lead to an increase in power output, because the gain in cycle efficiency is counteracted by a lower heat recovery factor, depending on the adopted working fluid and on the temperature of the heat source. A complete discussion on this issue can be found in Section 5.2. Article A general framework to select working fluid and configuratio...
. Intuitively, one can see (attached Figure) that the more tilted is the vapor saturation line of the working fluid in the T-s diagram, the higher is the available deltaT for internal heat recovery. A high deltaT (called deltaT_reg_id in the paper) leads to a high gain in cycle efficiency when a IHE is introduced, thus making this choice convenient.- Badges
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