Turbine Waste Heat Recovery Research Articles

An evaluation of wind turbine waste heat recovery using organic Rankine cycle

Wind turbine size has increased to megawatt capacity, and the related technologies and facilities have improved, including the cooling systems. Currently, all of the heat generated by wind turbine components is wasted to the environment. This study presents a conceptual design of a novel method for waste heat recovery of a wind turbine using an organic Rankine cycle (ORC). An organic Rankine cycle is implemented to the wind turbine as a part of the cooling system. The proposed system is thermodynamically modeled to evaluate the amount of recovered energy. Seven working fluids are chosen and investigated in the simulations to estimate the working fluid effect. The results revealed that the organic Rankine cycle can be a suitable choice for cooling wind turbines while simultaneously produce the power. Both exergy and energy analysis are conducted. A maximum power of 7.1 kW is provided by the proposed system using R134 when 20 K superheat is utilized. While R600a and SE36 stand on the next place. Furthermore, a minimum of 6.25 kW power is achievable. The generated work can be used as pump driving or electricity generation. In the next step, the thermal efficiency and total annual cost are optimized simultaneously using a multi-objective optimization for R134a as best working fluid in the thermodynamic viewpoint. It is found that the ideal efficiency of the system is obtained to be 14.7% with the total price of 7050 $/year. Finally, the effects of design parameters on the efficiency are obtained.

Optimization of the combined supercritical CO2 cycle and organic Rankine cycle using zeotropic mixtures for gas turbine waste heat recovery

In order to further improve the efficiency of the gas turbine, a novel combined supercritical CO2 regenerative cycle and organic Rankine cycle using zeotropic mixtures for waste heat recovery of gas turbine is proposed. The zeotropic mixtures used in the present study are cyclopentane/R365mfc. Exergoeconomic analysis is reported for the proposed system and parametric studies have been carried out to investigate the effect of system parameters on the exergy efficiency and the unit cost of electricity. The multi-objective optimization method based on genetic algorithm is chosen to obtain the optimum system parameters. The results show that the overall values of the exergoeconomic factor, the optimal exergy efficiency and the optimal unit cost of electricity of the proposed system are 31.88%, 62.23% and 3.95 cent/kW h, respectively. The obtained result reveals the superiority of the proposed combined regenerative S-CO2 cycle and ORC system compared to the combined basic S-CO2 cycle and ORC system, the combined recompression S-CO2 cycle and ORC system. Therefore, the proposed system is suitable for gas turbine waste heat recovery, and it has advantages of deep utilization of waste heat, high efficiency and low cost.

Prediction of generated power from steam turbine waste heat recovery mechanism system on naturally aspirated spark ignition engine using artificial neural network

The waste heat from exhaust gases represents a significant amount of thermal energy, which has conventionally been used for combined heating and power applications. This paper proposes a prediction model on the performance of a naturally aspirated spark ignition engine equipped with a waste heat recovery mechanism (WHRM) using steam turbine mechanism. The simulation method is created using an artificial neural network (ANN) to predict the power produced from this WHRM. The automated neural network was employed to run the simulation, where the ANN analysis used multilayer perceptrons as the network architecture, which is a feed-forward neural network architecture with uni-directional full connections between successive layers and applied Broyden–Fletcher–Goldfarb–Shanno algorithm iterative techniques to train the data. By using ANN, power generated from this WHRM could be predicted with good accuracy of 0.007, 0.011, and 0.016% error on training, test and validation data, respectively.

Performance analysis of the combined supercritical CO2 recompression and regenerative cycle used in waste heat recovery of marine gas turbine

With the aim to recover the marine gas turbine exhaust heat, and improve the ship part-load thermal efficiency, a combined cycle coupling supercritical CO2 recompression and regenerative cycle is proposed. The proposed system adopts modular design. The application process can choose the module according to the ship's need. The cycle parameters, including the output power, exergy efficiency, the heat exchanger area per unit power output (APR) and the levelized energy cost (LEC), have been analyzed and optimized. The multi-objective optimization method based on genetic algorithm is selected as the optimization method to obtain the optimum system parameter. From the viewpoints of the output power, compactness and economics, the obtained result reveals the superiority of the proposed cycle compared to the common supercritical CO2 recompression cycle, the common supercritical CO2 regenerative cycle and the combined cycle coupling two supercritical CO2 regenerative cycle. What’s more, the proposed system can effectively improve the part-load performance of the ship. When the gas turbine fails, the combined cycle could meet 80% propulsion power of the ship by enabling the second combustion chamber, which could be used as the backup generator and improve the safety of the ship operation. The proposed cycle is suitable for marine gas turbine waste heat recovery, it has advantages of deep utilization of waste heat, high compactness and low cost.

Economic evaluation of different scenarios for gas turbine waste heat recovery to produce water and power

ABSTRACTIn this study, economic analysis of different configurations of combined power and water systems is performed using DEEP software. Three different desalination systems including reverse osmosis (RO), multi-effect desalination (MED) and multi-stage flash (MSF) coupled to a gas turbine power plant with 2 × 165.1 MW capacity are considered and analysed. A specific capacity of 50,000 m3/day is assumed for all desalination systems. The results indicate that the RO system has the lowest simple payback time, while MED has the highest thermal utilisation. In terms of levelised cost of water, the RO system has the lowest amount with 1.03 $/(m3/day), while levelised cost of water for MED and MSF are equal to 1.47 and 1.93 $/(m3/day), respectively. Also sensitivity analysis showed that the fuel cost is the most effective parameter on the levelised cost of water. In general, it can be concluded that the RO system is the best choice in terms of economics.

Wind Turbine Waste Heat Recovery—A Short-Term Heat Loss Forecasting Approach

The transition from the era of massive renewable energy deployment to the era of cheaper energy needed has made scientists and developers more careful with respect to energy planning compared with a few years ago. The focus is—and will be—placed on retrofitting and on extracting the maximum amount of locally generated energy. The question is not only how much energy can be generated, but also what kind of energy and how it can be utilized efficiently. The waste heat coming from wind farms (WFs) when in operation—which until now was wasted—was thoroughly studied. A short-term forecasting methodology that can provide the operator with a better view of the expected heat losses is presented. The majority of mechanical (due to friction) and electro-thermal (i.e., generator) losses takes place at the nacelle while a smaller part of this thermal source is located near the foundation of the wind turbine (WT) where the power electronics and the transformers are usually located. That thermal load can be easily collected via a working fluid and then be transported to the nearest local community or nearby agricultural or small scale industrial units using the necessary piping.

ВЛИЯНИЕ РАЗЛИЧНЫХ СПОСОБОВ ИНТЕНСИФИКАЦИИ ТЕПЛООБМЕНА В ТЕПЛООБМЕННОМ АППАРАТЕ НА ХАРАКТЕРИСТИКИ ВОЗДУШНОЙ ТЕПЛОУТИЛИЗИРУЮЩЕЙ ТУРБИННОЙ УСТАНОВКИ

Выполнен анализ влияния перспективных способов интенсификации теплообмена в трубчатых теплообменниках на их тепловую и гидравлическую эффективность, а также на эффективность ВТТУ в целом. Представлено сравнение теплогидравлических и массогабаритных характеристик ТОА с различными способами внутренней и внешней интенсификации теплообмена.

Gas turbine waste heat recovery distillation system

This article presents a method for improving the gas turbine's performance through an efficient utilization of the waste heat in a distillation system with a special arrangement. This consists of two trains of VTE/MEB connected to increase the fresh water produced. Exhaust gases from the gas turbine are used in a multi-temperature level heat recovery system with five feed heaters, and gases are released to ambient at 130°C. Distillation top train has nine effects and evaporation range from 130 to 82°C while the bottom train has six effects with evaporation range from 76 to 46°C and is supplied with the steam leaves the last effect in the top train. Thermal analysis using a 32.67 MW gas turbine showed that the present arrangement can produce 3.2 million gallons per day (mgd) of fresh water with more than 4 g/kWh at a performance ratio ( PR) of 8.8. This is 34% more than that produced in an existing gas-turbine distillation combination and 14% more than that expected from a reverse osmosis plant driven by a bottoming Rankine power cycle.

Flow Distribution Characteristics and Control in Marine Gas Turbine Diffusers

The object of this study was to investigate flow distribution characteristics and control in the marine gas turbine diffusers most suitable for waste heat recovery systems. The major technical problems associated with nonuniform flow distributions in heat-exchanger or flow-equipment systems were reviewed. Various means to alleviate or minimize these undesirable problems were evaluated. Four sets of candidate flow-distribution data were selected from the measured exhaust velocities of typical marine gas turbines for input to the present study. A two-dimensional turbulent flow model for diffusers was developed and computerized, and five diffuser geometries suitable for marine gas turbine waste-heat recovery applications were investigated, based on the actual inlet velocity data. The exit flow distribution characteristics (velocity, mass-flux, pressure recovery, and temperature) and diffuser performance with and without flow-distribution controls were analyzed using the computer programs developed. It was found that nonuniform flow distribution in the gas turbine exhaust can reduce diffuser efficiency to half of that attainable with uniform flow, and that the diffuser exhaust velocities will be more uniform by using guide vanes and/or flow injection than merely using nonsymmetric diffusion angles. The diffuser efficiency can be improved 20 to 36 percentage points by using these contort means.

A Simplified Immiscible Liquid Dual Pressure Cycle for Gas Turbine Waste Heat Recovery

The hybrid steam/steam-nonane dual pressure cycle (cycle B) has previously been shown capable of extracting significantly more of the available energy in gas turbine exhausts than the conventional steam cycle (cycle A). Some awkward control and liquid separation problems are features of this cycle. This paper proposes a simpler steam/nonane cycle in which the steam and nonane flows are kept separate in the heat recovery vapour generator so that liquid separation at condensate temperatures only is necessary. In the new cycle much more of the heat uptake from the gas occurs in the liquid heaters and there are multiple pinch points. Compared to the conventional cycle, a much larger condensing surface is required, but the L.P. turbine requires about the same number of stages if it is of conventional design. Like cycle B, the turbine expansion is entirely dry and all shafts can have steam or water buffer seals, eliminating the possibility of fluid leakage usually associated with organic working fluids in power cycles.