The promise of the Kalina cycle: Using an ammonia-water mixture, the Kalina steam cycle may permit thermal-mechanical-electrical energy conversion efficiencies of 45 percent

IEEE Spectrum ◽  
1986 ◽  
Vol 23 (4) ◽  
pp. 68-70 ◽  
Author(s):  
Ronald K. Jurgen
2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.


Author(s):  
A. L. Kalina ◽  
H. M. Leibowitz

A new power generation technology often referred to as the Kalina cycle, is being developed as a direct replacement for the Rankine steam cycle. It may be applied to any thermal heat source, low or high temperature. Among several Kalina cycle variations there is one that is particularly well suited as a bottoming cycle for utility combined cycle applications. It is the subject of this paper. Using an ammonia/water mixture as the working fluid and a condensing system based on absorption refrigeration principles the Kalina bottoming cycle outperforms a triple pressure steam cycle by 16 percent. Additionally, this version of the Kalina cycle is characterized by an intercooling feature between turbine stages, diametrically opposite to normal reheating practice in steam plants. Energy and mass balances are presented for a 200 MWe Kalina bottoming cycle. Kalina cycle performance is compared to a triple pressure steam plant. At a peak cycle temperature of 950° F the Kalina plant produces 223.5 MW vs. 192.6 MW for the triple pressure steam plant, an improvement of 16.0 percent. Reducing the economizer pinch point to 15° F results in a performance improvement in excess of 30 percent.


2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Malapaka Chandrasekharam ◽  
Ganugula Rajkumar ◽  
Chikkam Srinivasa Rao ◽  
Thogiti Suresh ◽  
Yarasi Soujanya ◽  
...  

Two new ruthenium(II) mixed ligand terpyridine complexes, “Ru(Htcterpy)(NCS)(L1) (N(C4H9)4), mLBD1” and Ru(Htcterpy)(NCS)(L2)(N(C4H9)4), mLBD2 were synthesized and fully characterized by UV-Vis, emission, cyclic voltammogram, and other spectroscopic means, and the structures of the compounds are confirmed by 1H-NMR, ESI-MASS, and FT-IR spectroscopes. The influence of the substitution of L1 and L2 on solar-to-electrical energy conversion efficiency (η) of dye-sensitized solar cells (DSSCs) was evaluated relative to reference black dye. The dyes showed molar extinction coefficients of 17600 M−1 cm−1 for mLBD1 and 21300 M−1 cm−1 for mLBD2 both at λ maximum of 512 nm, while black dye has shown 8660 M−1 cm−1 at λ maximum of 615 nm. The monochromatic incident photon-to-collected electron conversion efficiencies of 60.71% and 75.89% were obtained for mLBD1 and mLBD2 dyes, respectively. The energy conversion efficiencies of mLBD1 and mLBD2 dyes are 3.15% ( mA/cm2,  mV, ) and 3.36% ( mA/cm2,  mV, ), respectively, measured at the AM1.5G conditions, the reference black dye-sensitized solar cell, fabricated and evaluated under identical conditions exhibited η-value of 2.69% ( mA/cm2,  mV, ).


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhammad Pramuda N.S ◽  
Muhammad Ridwan ◽  
Iqbal Iqbal Maulana

ABSTRAK Indonesia memiliki potensi panas bumi yang besar. Daerah potensi panas bumi seperti di daerah Cimanggu, Provinsi Jawa Barat umumnya memiliki sumber air panas. Sumber air panas selain dimanfaatkan untuk pariwisata, dapat pula dimanfaatkan sebagai pembangkit tenaga listrik. Temperatur sumber air panas yang relatif rendah antara 60° - 90°C membutuhkan teknologi khusus agar dapat dimanfaatkan sebagai pembangkit tenaga listrik. Siklus Kalina KCS34 merupakan siklus yang memanfaatkan campuran ammonia-air sebagai fluida kerja untuk menyerap energi kalor dari sumber panas bertemperatur rendah karena sifat dari campuran ammonia-air yang memiliki titik didih yang rendah. Fraksi campuran ammonia-air dan tekanan kondensor dapat mempengaruhi daya turbin dan efisiensi dari siklus Kalina KCS34. Simulasi optimasi fraksi campuran ammonia-air dan tekanan kondensor dilakukan untuk mengetahui besarnya fraksi campuran ammonia-air dan tekanan kondensor yang sesuai untuk digunakan sebagai pembangkit tenaga listrik di daerah Cimanngu, Provinsi Jawa Barat. Berdasarkan hasil simulasi, untuk mendapatkan kondisi pembangkit yang optimum di lokasi tersebut diperlukan fraksi campuran ammonia-air sebesar 87% dengan tekanan kondensor 7.6 bar sehingga akan dihasilkan daya turbin sebesar 73.57 kW dengan efisiensi sistem 14.85%. Kata kunci: Siklus Kalina, optimasi, campuran ammonia-air.  ABSTRACT Indonesia have a large potential of geothermal resources. Geothermal resource area such as Cimanggu area, West Java Province has natural hot spring resources. These natural hot spring resource can be utilized for eco tourism and electric power plant. Natural hot spring have relatively low water temperature between 60° - 90°C and it need special technology to be utilized as electric power plant. Kalina cycle KCS34 is a cycle that utilize ammonia-water mixture to absorb energy from low temperature natural hot spring source because of the properties of ammonia-water mixture that can boiled at low temperature. The fraction of ammonia-water mixture and the condensor pressure of the Kalina cycle KCS34 can affect the turbine output power and system efficiency. Optimization simulation was held to discover the required fraction of ammonia-water mixture and condenser pressure that suitable for generating electricity on Cimanggu area, West Java Province. According to the simulation results, the optimum fraction of ammonia-water mixture is 87% and the condensor pressure at 7.6 bar which will generate 73.57 kW of turbine power with 14.85% system efficiency. Keywords: Kalina cycle, optimization, ammonia-water mixture.


Author(s):  
Yoshiharu Amano ◽  
Keisuke Kawanishi ◽  
Takumi Hashizume

This paper reports results from experimental investigations of the dynamics of an ammonia-water mixture turbine system. The mixture turbine system features Kalina Cycle technology [1]. The working fluid is an ammonia-water mixture (AWM), which enhances the power production recovered from the low-temperature heat source [2], [3]. The Kalina Cycle is superior to the Rankine Cycle for a low temperature heat source [4], [5]. The ammonia-water mixture turbine system has distillation-condensation processes. The subsystem produces ammonia-rich vapor and a lean solution at the separator, and the vapor and the solution converge at the condenser. The mass balance of ammonia and water is maintained by a level control at the separator and reservoirs at the condensers. Since the ammonia mass fraction in the cycle has a high sensitivity to the evaporation/condensation pressure and vapor flow rate in the cycle, the pressure change gives rise to a flow rate change and then level changes in the separators and reservoirs and vice versa. From the experimental investigation of the ammonia-water mixture turbine system, it was observed that the sensitivity of the evaporating flow rate and solution liquid density in the cycle is very high, and those sensitivity factors are affected by the ammonia-mass fraction. This paper presents the experimental results of a study on the dynamics of the distillation process of the ammonia-water mixture turbine system and uses the results of investigation to explain the mechanism of the unstable fluctuation in the system.


Author(s):  
Ya Zheng ◽  
Saili Li ◽  
Dongshuai Hu ◽  
Yiping Dai

In various novel thermodynamic cycles which utilize waste heat and geothermal resources, the Kalina cycle is the most significant improvement in thermal power plant design and it has been considered as an ambitious competitor against the Organic Rankine Cycle. However, the kalina cycle faces the complicated separate process and the design of separators still depends on the experience empirical formulae. Therefore, the vertical gravity separator used for separating ammonia-water mixture plays a vital important role in this system. The separator should keep high separation performance and enable the system to operate with stability. In this paper, we propose the initial structure design of a vertical gravity separator according to the separation theories. Based on the initial structure design of separator, conventional separator has been improved by changing the structure and operational parameters, including the ammonia concentration, inlet velocity, diameter, angle and height of inlet, and that has been numerically simulated by the means of CFX in computational fluid dynamics. In-depth estimating the separating performance of vertical gravity separator, different structural and operational parameters of vertical gravity separator are simulated and discussed. The separation performance and the distribution of ammonia-water mixture are estimated including flow field, trajectories of motion of particles, pressure drop, separation efficiency and so on. The results can be expected to be of great technical interest as basis for the design of vertical gravity separators.


2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Norazreen Samsuri ◽  
Sheikh Ahmad Zaki Shaikh Salim ◽  
Md Nor Musa ◽  
Mohamed Sukri Mat Ali

Ocean Thermal Energy Conversion (OTEC) is a promising renewable energy technology with the concept to harness the energy stored at the surface seawater (SSW) and the cold deep seawater (DSW). The operation is based on the Rankine cycle, and involves at a minimum temperature difference of 20 K of the SSW and DSW to generate electricity. This research focuses on the economic efficiency of different working fluids used in the OTEC Rankine cycle. The various working fluids include ammonia, ammonia-water mixture (0.9), propane, R22, R32, R134a, R143a, and R410a. Most of the existing commercial OTEC systems use ammonia as the working medium despite its toxic nature. This study shows that the ammonia-water mixture still gives the best results in terms of heat transfer characteristics because of its greater transport properties and stability compared to other fluids. However, fluids such as propane and R32 can also be used as a substitute for ammonia-water mixture despite having slightly lower efficiency, because they are non-toxic and safer towards the environment. The same developmental model was used to present the proposed modified OTEC Rankine cycle, which shows a 4% increase in thermal cycle efficiency. This study reveals economically efficient and environmentally friendly working fluids.


2006 ◽  
Vol 110 (50) ◽  
pp. 25430-25440 ◽  
Author(s):  
Georg M. Hasselman ◽  
David F. Watson ◽  
Jonathan R. Stromberg ◽  
David F. Bocian ◽  
Dewey Holten ◽  
...  

Author(s):  
E. Olsson ◽  
U. Desideri ◽  
S. S. Stecco ◽  
G. Svedberg

A number of studies have shown that the Kalina cycle, using an ammonia-water mixture, can reach higher efficiencies than the normal steam Rankine cycle. In this paper, the Kalina cycle, with a gas turbine topping cycle is applied to cogeneration for district heating. Since the district heating temperatures vary with the heat demand over the year, this application may prove to be especially suitable for the Kalina cycle with its many degrees of freedom in the condensation system. A theoretical comparison between different bottoming cycles producing heat for a typical Scandinavian district heating network has been carried out. The Kalina cycle, the Rankine cycle with a mixture of ammonia and water as the working fluid and the normal single pressure steam Rankine cycle are compared. It is shown that a simple Rankine cycle with an ammonia-water mixture as the working fluid produces more heat and power than the steam Rankine cycle. The best results, however, are obtained for the Kalina cycle, which generates considerably higher heat and power output than the steam Rankine cycle.


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