66 Fluid selection 66 M Antonelli Sistemi di trattamento e recupero energetico

66 fluid selection 66 m antonelli sistemi di

This preview shows page 66 - 76 out of 79 pages.

66 Fluid selection 66 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 66

Subscribe to view the full document.

R600a R245fa R152a Same heat exchanger efficiency + Highest power output = Highest overall efficiency 67 Fluid selection 67 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 67
Dynamic numerical model Average exchanged heat: Average cycle efficiency: Second law efficiency: Average overall efficiency: 68 68 68 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 68

Subscribe to view the full document.

Economizer Economizer Evaporator Evaporator Superheater Superheater Expansion device Expansion device Water cooled condenser Water cooled condenser Variable speed feed pump controlled by the evaporator level Variable speed feed pump controlled by the evaporator level Flue gas temperature and mass flow input Flue gas temperature and mass flow input 9 69 69 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel Dynamic numerical model
Image of page 69
Components Setup WankelExpander: volumetric flow rate and isentropic efficiency computed through the numerical model used for fluid selection as a function of rotating speed and pressure ratio ; Pump: variable speed pump controlled by the level of liquid into the evaporator: the efficiency was considered constant; Heatexchanger: discretized in various section to grant a more real trend of the exchange curves; Condenser: modelled as a temperature-imposed, phase-separation chamber. 70 Dynamic numerical model 9 70 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 70

Subscribe to view the full document.

Flue gas characterization Two different load cycles tested Load cycle 1 Load cycle 2 719 71 71 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 71
Control strategies Control strategy n°1: constant rotating speed of the expander; Control strategy n°2: fixed set point of saturation temperature and rotating speed of the expander controlled; Control strategy n°3: variable set point of saturaton temperature and variable rotating speed of the expander ? ??? ????? = ? ( ´ ? ? ??? ) ? + ? ( ´ ? ? ??? ) + ? Evaporating temperature left free of varying without any control The value of the set point must be defined a priori Polynomial function of intake pressure and volumetric flow rate 12 729 72 72 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 72

Subscribe to view the full document.

Superheated cycles 13 739 73 73 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 73
COMPARISON OF STRATEGIES Load Cycle 2 Strategy I @ 2500 rpm Strategy II @ Tsat= 115°C Strategy III Average net power output [kW] 14.71 15.66 15.66 Exchanged heat [kW] 119.59 114.30 114.32 Average second law efficiency [%] 43.18 47.82 47.83 Average overall efficiency [%] 8.38 8.92 8.92 14 749 74 74 M. Antonelli - Sistemi di trattamento e recupero energetico da biomassa Espansore Wankel
Image of page 74

Subscribe to view the full document.

1. Lower overall efficiency. Possibility of approaching or overvcoming the critical temperature ; 2. Optimal results; the set point has to be properly tuned, otherwise overall efficiency decreases; 3. Control strategy III always provided the best results in terms of output power and overall efficiency.
Image of page 75
Image of page 76
  • Fall '15

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask You can ask ( soon) You can ask (will expire )
Answers in as fast as 15 minutes