The adiabatic transformation The adiabatic expansion of the vapor in the Mollier diagram The isobar

The adiabatic transformation The adiabatic expansion of the vapor in the Mollier diagram The isobaric transformation The vapor pressure of water The isothermal transformation enthalpy and internal energy transformation isochoric The transformation isoenthalpic zach anner The density of water vapor The engine Manson free piston to double effect
As announced in the comments a few days ago in this post is compared to the thermodynamic cycle of the engine Hummingbird with the Rankine cycle through the cycle for engine Uniflow. The three cycles were constructed recovering the same operating conditions adopted in previous posts. It is noted that the diagrams shown below by using exactly the same amount of steam per cycle (0,03492g). The absorption heat in the three cases is therefore identical and equal to 82,4J. The picture below shows the cycle of motor Hummingbird. For details on the cycle, see the dedicated post.
The engine Uniflow adopts the same solution of the Hummingbird as regards the discharge of the steam, zach anner while it is provided with a pilot operated valve as regards the placing of the steam. The piloting of the valve makes it possible both the extraction of work isobar, both the annulment of the pressure difference existing zach anner between the expansion chamber and placing at the time of the opening of the light load thus eliminating the problem of the volume thief. Below is plotted the cycle of an engine Uniflow.
The pressure curve, which in Hummingbird from point C to stop at the point D, nell'Uniflow continues to the point E. In this point the pressure in the engine is equal to the inlet pressure. In point E opens the inlet valve and begins the process isobaric to the point A. At this point, the inlet valve closes and begins the adiabatic expansion up to point B. At point B opens the exhaust port and the pressure returns to step C isochoric process. The diagram shows that, compared to the area of the Hummingbird, the area of the loop dell'Uniflow, that his useful work, increases the area of green (1,5J). The next image is relative to the Rankine cycle, which from the theoretical point of view represents the maximum attainable with the steam.
In the Rankine cycle in addition to the inlet valve, is appropriately piloted also the exhaust valve. zach anner While in the cycle Uniflow (and that of the Hummingbird) the adiabatic expansion is truncated at point B, the Rankine cycle expansion continues to point F. At this point the pressure equals the pressure in the engine exhaust. At this point the exhaust valve opens and starts an isobaric process zach anner to the point C. At point C the exhaust port closes and starts the adiabatic compression and the rest of the cycle continues zach anner in the same way as already seen for the case Uniflow. The diagram shows that, compared to the area of the Hummingbird, the area of the Rankine cycle, ie its useful work, increases the surface of green color (1,5J) and the surface of red color (1,3J). In the following table were collected data relating to the three cycles just discussed. Working useful heat absorbed Performance Cycle Hummingbird 10,8J 82.4 J Cycle Uniflow 13.1% (10.8 + 1.5) J 82.4 J 14.9% Rankine Cycle (10.8 + 1.5 + 1 3) J J 82.4 16.5% The numbers in the table show that the cycle of Hummingbirds can rip Rankine yield of 79.4%, a value surprisingly high in view of the extreme simplicity of the engine. The engine Uniflow, zach anner which is thermodynamically place at an intermediate level between the Hummingbird and the Rankine, produces a yield of 14.9%, which is equivalent to an efficiency of 13.7% compared to the Hummingbird.
Thermodynamic cycles (10) thermodynamic cycles gases (6) thermodynamic cycles of steam (7) Cold Fusion (3) E-Cat (3) Cold Fusion (3) Electricity Generation (3) The Brayton cycle (2) The cycle Carnot (1) Stirling cycle (2) The cycle isobaric-isochoric gases (1) The cycle isobaric-isochoric Steam (1) The Rankine Cycle (2) The motor Cayley exothermic (9) The motor Manson ( 9) The adiabatic (2) isobaric transformation (2) The transformation at constant volume (2) The transformation isoenthalpic (2) The isothermal transformation (2) Motor Hummingbird (15) Engines double effect (9) Engines monoeffetto (22) Regenerator heat (6) thermal sources (2) Clinical (7) theory (22) Theory of Gases (10) Theory of vapor (15) Heat Transfer (4) Transformations gases (7)
Source Thermal Price [EUR / kWh] Ethanol 0.20 0.20 LPG tank Unleaded Fuel 0.20-0.25 0.20 Electricity 0.18 0.10 Methane Pellets 0,050 heat pump COP = 4 0,050- 0.062 E-Cat (COP = 6) 0.038 0.033 to 0.042 Wood Ni-H 2 (?) 0,001 (?)