Specific power output

In order to be competitive in the market of energy storage devices SC must demonstrate the specific power output of about 10 kW/kg for a charge/discharge at 95% efficiency. 

To optimize the specific power output of the cycle, we let 9 (specific power output)/9T7 =0 first and then 9 (specific power output)/ dTj = 0 as shown in Tables 7.1a and 7.1b. 

Let r5 = 80°C and Tj = 220°C the optimized specific power output of the cycle is 14.53 kW/m. At the maximum optimized specific power output condition, LMTDh = 80K, LMTDh = 60K, rate of heat added from the heat source = 1208 kW, rate of heat removed to the heat sink = —865.2 kW, power required by the isentropic pump = —201.8 kW, power produced by the isentropic turbine = 544.9 kW, net power produced = 343.0 kW, and efficiency of the cycle = 28.39%, as shown in Fig. 7.9c. 

Then let 9 (specific power output)/ = 0. It is seen that 9 (specific power output)/9T5 = 0 occurs at Ts = 12°C as shown in Table 7.3b. 

Chen, J. and Wu, C., Maximum specific power output of a two-stage endo-reversible Combined cycle. Energy The International Journal, 20(4), 305-309, 1995. 

The principle of thermionic conversion is that of a diode, in which the cathode (emitter) emits electrons that are collected at the anode (collector). Alloys of W, Re, Mo, Ni or Ta are used as emitters, and the diodes operate at temperatures of about 2200 K. The efficiency varies between about 1 and 10%, depending on the power. In order to take advantage of thermionic conversion, radionuclides of high specific power output (high power per mass unit) are needed, such as Pu, Ac,... 

Lubricants for the next generation of passenger engines will have to cope with increased specific power output, longer drain intervals, reduced oil consumption... 

The Figure 4-60 shows that only reactions with maximum specific heat production rates of less than 130 W/kg are safety technically acceptable if the batch size amounts to 6 m. If the maximum specific power output is expected to be higher, the batch size has to be reduced. The limit curve has to be recalculated for each batch size because the maximum vapour velocity in the reactor directly depends on this batch size. For the sample process considered, Figure 4-61 additionally provides the curves for a 5 m batch size. It can be seen that in the case of this reduced total batch volume, maximum reaction power outputs up to 400 W/kg could be tolerated. 

Blue Energy Salinity Gradient for Energy Conversion 287 According to such considerations, the actual specific power output can be calculated as... 

Chen, J. (1994). The Maximum Power Output and Maximum Efficiency of an Irreversible Carnot Heat Engine, /, Phys. D Appl. Phys., Vol. 27, pp. 1144-1149 Chen, J. (1996). The Efficiency of an Irreversible Combined Cycle at Maximum Specific Power Output, /, Phys. D Appl. Phys. Vol. 29, pp. 2818-2822 Chen, L. . Zhang, W. Sun, F. (2007). Power, efficiency, entropy generation rate and ecological optimization for a class of generalized universal heat engine cycles. Applied Energy, Vol. 84, pp. 512-525... 

---