Flash-type barometric desalination plant powered by waste heat from electricity power stations in Cyprus

2007 ◽  
Vol 84 (1) ◽  
pp. 66-77 ◽  
Author(s):  
G.G. Maidment ◽  
I.W. Eames ◽  
M. Psaltas ◽  
A. Lalzad ◽  
K. Yiakoumetti
2016 ◽  
Vol 100 ◽  
pp. 646-657 ◽  
Author(s):  
Luca Cioccolanti ◽  
Andrea Savoretti ◽  
Massimiliano Renzi ◽  
Flavio Caresana ◽  
Gabriele Comodi

Author(s):  
Leonardo Pierobon ◽  
Richard Chan ◽  
Xiangan Li ◽  
Krishna Iyengar ◽  
Fredrik Haglind ◽  
...  

The implementation of waste heat recovery units on oil and gas offshore platforms demands advances in both design methods and control systems. Model-based control algorithms can play an important role in the operation of offshore power stations. A novel regulator based on a linear model predictive control (MPC) coupled with a steady-state performance optimizer has been developed in the simulink language and is documented in the paper. The test case is the regulation of a power system serving an oil and gas platform in the Norwegian Sea. One of the three gas turbines is combined with an organic Rankine cycle (ORC) turbogenerator to increase the energy conversion efficiency. Results show a potential reduction of frequency drop up to 40% for a step in the load set-point of 4 MW, compared to proportional–integral control systems. Fuel savings in the range of 2–3% are also expected by optimizing on-the-fly the thermal efficiency of the plant.


Author(s):  
David A. Renfroe

Although this is not a new idea, it certainly seems to be a forgotten idea; use lunar materials to construct solar power stations at a geosynchronous orbit to beam energy via microwave to the earth’s surface at a safe 225 watts per square meter. In the 1970’s Gerard O’Neill, physics professor at Princeton and founder of Space Studies Institute, proposed this idea (1). Significant research on the establishment of lunar based mining stations, lunar launch mechanisms, low earth orbit manufacturing stations, and geosynchronous power stations was conducted. Without developing new physics principles and with less capital than was being invested in the fusion technology, a clean solar based energy generation and delivery system was possible for any point in the world. The obvious benefit would be the elimination of carbon-based fuel consumption and associated pollution, and the not-so-obvious benefit of the elimination of the 2nd law thermal pollution from any earth based energy conversion to electricity. Heat rejection from all current electricity generating facilities: coal, gas, nuclear, geothermal, even solar, reject at least two thirds of the energy converted as waste heat. By moving the heat rejection process to the extra-terrestrial environs, the useful energy available for humanity for a given temperature rise in the atmosphere, triples at least. Thus, the life style of all of humanity can practically be increased without harm to the environment. This paper will give an overview of that technology, its history from the mid 1970’s till now, and why it has not been considered in the modern context of the new “hydrogen” based energy system.


Author(s):  
David J. White

Using a hydraulic air compressor (HAC) instead of a mechanical driven compressor in a gas turbine based system can provide significant performance benefits. In particular very high thermal efficiencies can be achieved at modest firing temperatures. Although the HAC based hybrid system has many applications this paper reports on a study and analysis of such a hybrid as it might be integrated into a coal to electricity power plant. In this specific case the HAC is used to provide both compressed oxygen depleted air to a recuperated, fired turbo-expander and low-pressure oxygen enriched air to a coal gasifier. The oxygen enriched air improves the lower heating value of the derived coal gases obtained allowing them to be compressed economically and injected into the combustion system. Run-of-stream applications of the HAC can provide thermal efficiencies on the order of 70% or higher, whilst pumped approaches can achieve efficiencies around 50%. The pumped water HAC combined with a recuperated gas turbine is effectively an intercooled, and recuperated (ICR) cycle. In the non-pumped HAC systems the very high thermal efficiencies can provide coal to electricity conversion efficiencies on the order of 60%. The actual efficiency depends strongly on the type of gasifier employed and on whether or not the gasifier employs waste heat recovery. The overall cost of electricity so generated is very competitive despite the high capital costs associated with coal handling and gasification.


2015 ◽  
Vol 82 ◽  
pp. 18-29 ◽  
Author(s):  
Luca Cioccolanti ◽  
Andrea Savoretti ◽  
Massimiliano Renzi ◽  
Flavio Caresana ◽  
Gabriele Comodi

Author(s):  
G. A. Adebiyi

A combined electrical/mechanical and thermal power generating system is undoubtedly the way to go for optimum overall efficiency in energy conversion. Traditionally, electric power is generated in centralized power stations and subsequently supplied to consumers via extensive grid distribution networks. Waste heat is a by-product that cannot inexpensively be conveyed to meet the demand for thermal power in the communities served. Consequently, the needed thermal power is produced either using the high grade electricity delivered from the grid supply, or by combustion of expensive fuels such as natural gas and oil. Cogeneration and CHP (Cooling, Heating, and Power) systems are designed to utilize waste heat from in-house electrical/mechanical power producing devices such as micro turbines and diesel engines used in industries that are located in the community or district. The generation of mechanical and thermal power from a single fuel input significantly enhances the overall conversion efficiency, which translates to lower CO2 emissions to the environment. Greater stability and reliability in power supply at the community level is achieved via the deployment of CHP systems that provide power on the required scale as well as meet local demand for cooling and/or heating. The magnitude of efficiency gain for CHP systems is often overstated simply because the quality difference between electrical/mechanical power and thermal power is not factored into the equation. This paper focuses on a complete thermodynamic analysis of CHP systems on the basis of the first and second laws of thermodynamics.


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