Evaluation of Operational Performance of a Gas Turbine Cogeneration Plant With Intake Air Cooled by Ice Storage

2000 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Ambient Air ◽  
Maximum Power ◽  
Operational Performance ◽  
Mixed Integer ◽  
Ice Storage ◽  
Air Cooling ◽  
Cogeneration Plant ◽  
Maximum Power Output

A disadvantage of a gas turbine cogeneration plant is a decrease in maximum power output during the period with high ambient air temperature. One of the ways to avoid this disadvantage is to cool intake air by ice storage and augment maximum power output. An advantage of this system is to utilize a discounted rate for energy charge of electricity consumed to drive electric compression refrigerators for ice storage during the nighttime. The objective of this paper is to investigate the effect of intake air cooling by ice storage on the operational performance of a gas turbine cogeneration plant for district heat and power supply. An optimal operational planning model based on the mixed-integer linear programming is used to assess the effect rationally and efficiently. In a numerical study, the operational performances of gas turbine cogeneration plants with and without intake air cooled by ice storage are compared with each other, and the effect of intake air cooling on the operational strategy and cost is clarified.

Effect of Inlet Air Cooling by Ice Storage on Unit Sizing of a Gas Turbine Cogeneration Plant

2004 ◽  
Vol 126 (2) ◽  
pp. 351-357 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Maximum Power ◽  
Mixed Integer ◽  
Ice Storage ◽  
Air Cooling ◽  
Cogeneration Plant ◽  
Maximum Heat ◽  
Maximum Power Output

In the commercial sector, heat and power demands peak in the summer daytime because of high space cooling demands, and cogeneration plants are required to produce maximum heat and power to meet their demands. However, gas turbine cogeneration plants have the disadvantage of decreases in maximum power output in the summer daytime, which reduces the availability of gas turbines. One of the ways to avoid the aforementioned disadvantage is to cool inlet air and augment maximum power output. In addition, one of the ways for inlet air cooling is to make ice by driving electric compression refrigerators using off-peak power generated during the nighttime, store it in ice banks, and use its heat for inlet air cooling during the on-peak period. The objective of this paper is to investigate the effect of inlet air cooling by ice storage on the unit sizing and cost of a gas turbine cogeneration plant. An optimal unit sizing method based on the mixed-integer linear programming is used to rationally determine equipment capacities and operational strategies of the plant. A numerical study is conducted, in which the gas turbine cogeneration plants with and without inlet air cooled by ice storage are compared with each other, and the effect of inlet air cooling on the equipment capacities as well as the annual total cost and its items is clarified.

Effect of Inlet Air Cooling by Ice Storage on Unit Sizing of a Gas Turbine Cogeneration Plant

2002 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Maximum Power ◽  
Mixed Integer ◽  
Ice Storage ◽  
Air Cooling ◽  
Cogeneration Plant ◽  
Maximum Heat ◽  
Maximum Power Output

In the commercial sector, heat and power demands peak in the summer daytime because of high space cooling demands, and cogeneration plants are required to produce maximum heat and power to meet their demands. However, gas turbine cogeneration plants have the disadvantage of decreases in maximum power output in the summer daytime, which reduces the availability of gas turbines. One of the ways to avoid the aforementioned disadvantage is to cool inlet air and augment maximum power output. In addition, one of the ways for inlet air cooling is to make ice by driving electric compression refrigerators using off-peak power generated during the nighttime, store it in ice banks, and use its heat for inlet air cooling during the on-peak period. The objective of this paper is to investigate the effect of inlet air cooling by ice storage on the unit sizing and cost of a gas turbine cogeneration plant. An optimal unit sizing method based on the mixed-integer linear programming is used to rationally determine equipment capacities and operational strategies of the plant. A numerical study is conducted, in which the gas turbine cogeneration plants with and without inlet air cooled by ice storage are compared with each other, and the effect of inlet air cooling on the equipment capacities as well as the annual total cost and its items is clarified.

Oxidation of combined ingestion of glucose and fructose during exercise

2004 ◽  
Vol 96 (4) ◽  
pp. 1277-1284 ◽  
Author(s):  
Roy L. P. G. Jentjens ◽  
Luke Moseley ◽  
Rosemary H. Waring ◽  
Leslie K. Harding ◽  
Asker E. Jeukendrup
Keyword(s):  
Power Output ◽  
Statistical Significance ◽  
Random Order ◽  
Carbohydrate Oxidation ◽  
Maximum Power ◽  
The Other ◽  
Cycling Exercise ◽  
Oxidation Rates ◽  
Maximum Power Output ◽  
Exercise Period

The purpose of the present study was to examine whether combined ingestion of a large amount of fructose and glucose during cycling exercise would lead to exogenous carbohydrate oxidation rates >1 g/min. Eight trained cyclists (maximal O2consumption: 62 ± 3 ml·kg-1·min-1) performed four exercise trials in random order. Each trial consisted of 120 min of cycling at 50% maximum power output (63 ± 2% maximal O2consumption), while subjects received a solution providing either 1.2 g/min of glucose (Med-Glu), 1.8 g/min of glucose (High-Glu), 0.6 g/min of fructose + 1.2 g/min of glucose (Fruc+Glu), or water. The ingested fructose was labeled with [U-13C]fructose, and the ingested glucose was labeled with [U-14C]glucose. Peak exogenous carbohydrate oxidation rates were ∼55% higher ( P < 0.001) in Fruc+Glu (1.26 ± 0.07 g/min) compared with Med-Glu and High-Glu (0.80 ± 0.04 and 0.83 ± 0.05 g/min, respectively). Furthermore, the average exogenous carbohydrate oxidation rates over the 60- to 120-min exercise period were higher ( P < 0.001) in Fruc+Glu compared with Med-Glu and High-Glu (1.16 ± 0.06, 0.75 ± 0.04, and 0.75 ± 0.04 g/min, respectively). There was a trend toward a lower endogenous carbohydrate oxidation in Fruc+Glu compared with the other two carbohydrate trials, but this failed to reach statistical significance ( P = 0.075). The present results demonstrate that, when fructose and glucose are ingested simultaneously at high rates during cycling exercise, exogenous carbohydrate oxidation rates can reach peak values of ∼1.3 g/min.

scholarly journals Scaling of Power Output in Fast Muscle Fibres of the Atlantic Cod During Cyclical Contractions

1992 ◽  
Vol 170 (1) ◽  
pp. 143-154 ◽  
Author(s):  
M. ELIZABETH ANDERSON ◽  
IAN A. JOHNSTON
Keyword(s):  
Steady State ◽  
Power Output ◽  
Standard Length ◽  
Atlantic Cod ◽  
Maximum Power ◽  
Fast Muscle ◽  
Muscle Fibres ◽  
Cycle Frequency ◽  
Maximum Power Output ◽  
Length Changes

Fast muscle fibres were isolated from abdominal myotomes of Atlantic cod (Gadus morhua L.) ranging in size from 10 to 63 cm standard length (Ls). Muscle fibres were subjected to sinusoidal length changes about their resting length (Lf) and stimulated at a selected phase of the strain cycle. The work performed in each oscillatory cycle was calculated from plots of force against muscle length, the area of the resulting loop being net work. Strain and the number and timing of stimuli were adjusted to maximise positive work per cycle over a range of cycle frequencies at 8°C. Force, and hence power output, declined with increasing cycles of oscillation until reaching a steady state around the ninth cycle. The strain required for maximum power output (Wmax) was ±7-11% of Lf in fish shorter than 18 cm standard length, but decreased to ±5 % of Lf in larger fish. The cycle frequency required for Wmax also declined with increasing fish length, scaling to Ls−0.51 under steady-state conditions (cycles 9–12). At the optimum cycle frequency and strain the maximum contraction velocity scaled to Ls−0.79. The maximum stress (Pmax) produced within a cycle was highest in the second cycle, ranging from 51.3 kPa in 10 cm fish to 81.8 kPa in 60 cm fish (Pmax=28.2Ls0.25). Under steady-state conditions the maximum power output per kilogram wet muscle mass was found to range from 27.5 W in a 10 cm Ls cod to 16.4 W in a 60 cm Ls cod, scaling with Ls−0.29 and body mass (Mb)−0.10 Note: To whom reprint requests should be sent

Effect of Ethanol-Air Equivalence Ratio on Performance of an Endoreversible Otto Engine

2011 ◽  
Vol 110-116 ◽  
pp. 273-277
Author(s):  
Rahim Ebrahim ◽  
Mahmoud Reza Tadayon ◽  
Farshad Tahmasebi Gandomkari ◽  
Kamyar Mahbobian
Keyword(s):  
Performance Evaluation ◽  
Compression Ratio ◽  
Power Output ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Maximum Power ◽  
Otto Cycle ◽  
World Community ◽  
Maximum Power Output ◽  
The World

Today, the world community is looking for fuel efficient and environmentally viable alternatives for many of the traditional energy conversion approaches. This development has further worked to increase the technical focus on conventional cycles for making them more optimum in terms of performance. Hence, the objective of this paper is to study the effect of ethanol-air equivalence ratio on the power output and the indicated thermal efficiency of an air standard Otto cycle. Optimization of the cycle has been performed for power output as well as for thermal efficiency with respect to compression ratio. The results show that the maximum power output, the optimal compression ratio corresponding to maximum power output point, the optimal compression ratio corresponding to maximum thermal efficiency point and the working range of the cycle first increase and then decrease as the equivalence ratio increases. The result obtained herein provides a guide to the performance evaluation and improvement for practical Otto engines.

Performance Improvement of Gas Turbine Power Plant by Intake Air Passive Cooling Using Phase Change Material Based Heat Exchanger

2017 ◽  
Author(s):  
Devendra Dandotiya ◽  
Nitin D. Banker
Keyword(s):  
Heat Exchanger ◽  
Ambient Temperature ◽  
Phase Change ◽  
Gas Turbine ◽  
Air Temperature ◽  
Power Output ◽  
Ambient Air ◽  
Passive Cooling ◽  
Air Intake ◽  
Change Material

The power output of a gas turbine plant decreases with the increase in ambient temperature. Moreover, the ambient temperature fluctuates about 15–20°C in a day. Hence, cooling of intake air makes a noticeable improvement to the gas turbine performance. In this regard, various active cooling techniques such as vapor compression refrigeration, vapor absorption refrigeration, vapor adsorption refrigeration and evaporative cooling are applied for the cooling of intake air. This paper presents a new passive cooling technique where the intake air temperature is reduced by incorporating phase change material (PCM) based heat exchanger parallel to conventional air intake line. During the daytime, the air is passed through the PCM which has melting temperature lower than the peak ambient temperature. This will reduce the ambient air temperature before taking to the compressor. Once the PCM melts completely, the required ambient air would be drawn from the ambient through conventional air intake arrangement. During the night, when there is lower ambient temperature, PCM converts from liquid to solid. The selected PCM has a melting temperature less than the peak ambient temperature and higher than the minimum ambient temperature. It is observed from the numerical modeling of the PCM that about four hours are required for the melting of PCM and within this time, the intake air can also be cooled by 5°C. The thermodynamic analysis of the results showed about 5.2% and 5.2% improvement in net power output and thermal efficiency, respectively for four hours at an ambient temperature of 45°C.

Sign in / Sign up

Export Citation Format

Share Document