Cooling down the world oceans and the earth by enhancing the North Atlantic Ocean current

The world is going through intensive changes due to global warming. It is well known that the reduction in ice cover in the Arctic Ocean further contributes to increasing the atmospheric Arctic temperature due to the reduction of the albedo effect and increase in heat absorbed by the ocean’s surface. The Arctic ice cover also works like an insulation sheet, keeping the heat in the ocean from dissipating into the cold Arctic atmosphere. Increasing the salinity of the Arctic Ocean surface would allow the warmer and less salty North Atlantic Ocean current to flow on the surface of the Arctic Ocean considerably increasing the temperature of the Arctic atmosphere and release the ocean heat trapped under the ice. This paper argues that if the North Atlantic Ocean current could maintain the Arctic Ocean ice-free during the winter, the longwave radiation heat loss into space would be larger than the increase in heat absorption due to the albedo effect. This paper presents details of the fundamentals of the Arctic Ocean circulation and presents three possible approaches for increasing the salinity of the surface water of the Arctic Ocean. It then discusses that increasing the salinity of the Arctic Ocean would warm the atmosphere of the Arctic region, but cool down the oceans and possibly the Earth. However, it might take thousands of years for the effects of cooling the oceans to cool the global average atmospheric temperature

Seasonal pumped hydropower storage role in responding to climate change impacts on the Brazilian electrical sector

Since Brazil's major energy resources are renewable and directly related to climate factors, it is among the countries most likely of being affected by climate change. Given Brazil's high hydropower storage capacity and the strong seasonal patterns of its renewable resources, introducing Seasonal Pumped Hydropower Storage (SPHS) can help mitigate these challenges. To this end, a methodology is proposed that links the dynamic system-optimization model – MESSAGEix - to regional climate model simulations, called the Brazilian Electricity System MESSAGEix Model (BESMM). This model, with its detailed hydropower representation, is capable of integrating data from three climate change scenarios with the country's energy system. Climate change introduces a new dimension to this approach, as there is evidence of increasing the seasonal imbalance of variable renewable resources in Brazil. BESMM results suggest that SPHS can play a fundamental role in achieving a 100 % renewable matrix by 2100 in RCP 2.6 scenario, as well as enhancing the renewable energy endowment in scenarios RCP 4.5 and RCP 8.5. A reduction of up to 68 % of CO2 emissions is predicted in scenarios incorporating SPHS, compared to scenarios without SPHS

High velocity seawater air-conditioning with thermal energy storage and its operation with intermittent renewable energies

The rapid increase in cooling demand for air-conditioning worldwide brings the need for more efficient cooling solutions based on renewable energy. Seawater air-conditioning (SWAC) can provide base-load cooling services in coastal areas utilizing deep cold seawater. This technology is suggested for inter-tropical regions where demand for cooling is high throughout the year, and it has been implemented in islands with short distances from the coast and the deep sea. This paper proposes adjustments to the conventional design of SWAC plants to reduce implementation risks and costs. The approach is named high velocity SWAC and consists of increasing the excavation depth of the seawater pump station up to 20 m below the sea level, compared to 2 to 5 m in conventional SWAC projects. This allows a twofold increase in the speed of inlet pipeline seawater and cooling load of the plant. The cooling load can be expanded twofold with only 55% capital cost and 83% project costs, compared with the costs of a new system. In addition, this article shows that high velocity SWAC plants with thermal energy storage will have an important role supporting the dissemination of intermittent renewable sources of energy in regions where SWAC is a viable cooling alternative

Efficiency and NOx emission optimization by genetic algorithm of a coal-fired steam generator modeled with artificial neural networks

High level of efficiency is pursued whenever an energy convertion system is operated, such as steam generators, but emission contents must be kept within legal and reasonable values at the same time. The interdependence of these two factors often limit the system performance, and optimization procedures allow for finding combinations of parameters that may satisfy that anthagonism and help technical teams to operate actual systems. This study aims to find operating points of an actual superheated steam generator that combine high efficiency with low NOx emissions, based on the system data analysis. The novelty presented in the paper comes from the assessment of a power plant placed on a hot, humid and seasonal wheather, witch differs from previous works. The steam generator efficiency and NOx emission are represented by two independent Artificial Neural Networks (ANNs), based on a common database. The influence of the ANNs selected input paremeters are assessed with the aid of Design of Experiment, which points out that 2 out of 10 inputs to efficiency can be removed, but none to NOx emissions. The objective function aims to find the combination of input values that allow to operate the steam generator with the highest efficiency and the lowest NOx emission, covering three weighting combinations: 50 to 50, 75 to 25 and 90 to 10 in percentage of efficiency in respect to NOx emission. The genetic algorithm optimization procedure identified input values that guaranty 97.95% efficiency and 222.28 mg/mN3 of NOx emission based on the reference values of 98% and 220.00 mg/mN3, when assuming the 90 to 10 ponderation