Amount Of Excess Heat Research Articles

The Importance of Controlling the Chemistry of Pre-Oxidized Chromite Pellets for Submerged Arc Furnace FeCr Smelting: a Study on Furnace Si Control

South African FeCr operations have over time moved to running furnaces on predominantly pelletized concentrate feeds. This has brought about several changes in how submerged arc FeCr furnaces are operated. In particular, raw material management has become a critical factor to ensure that maximum value is derived from the material, and to minimize the impact of process upsets when they occur. When pre-oxidized pellets are produced, variations in the SiO2 fraction of the pellets will influence the liquidus temperature of the pellet material. Lower liquidus temperatures are undesirable when smelting pellets, since this can lead to impaired pre-reduction of iron oxides in the upper parts of the furnace. Further to this, if for example the furnace electrodes are positioned incorrectly, an excess amount of heat may be generated in the upper parts of the furnace – this can lead to excessive reduction of SiO2 to Si, which in turn reports to the FeCr product as a contaminant. In this paper, the effect of the chemistry of the pellet, electrode control and slag chemistry is studied. It was found that no one factor can fully explain the Si content of the alloy, however, with more modern tools, the industry is one step closer to fully predictive control. Some practical aspects of ensuring that the alloy Si specification is met.

Liquid Air Energy Storage for Decentralized Micro Energy Networks with Combined Cooling, Heating, Hot Water and Power Supply

Liquid air energy storage (LAES) has been regarded as a large-scale electrical storage technology. In this paper, we first investigate the performance of the current LAES (termed as a baseline LAES) over a far wider range of charging pressure (1 to 21 MPa). Our analyses show that the baseline LAES could achieve an electrical round trip efficiency (eRTE) above 60% at a high charging pressure of 19 MPa. The baseline LAES, however, produces a large amount of excess heat particularly at low charging pressures with the maximum occurred at ∼1 MPa. Hence, the performance of the baseline LAES, especially at low charging pressures, is underestimated by only considering electrical energy in all the previous research. The performance of the baseline LAES with excess heat is then evaluated which gives a high eRTE even at lower charging pressures; the local maximum of 62% is achieved at ∼4 MPa. As a result of the above, a hybrid LAES system is proposed to provide cooling, heating, hot water and power. To evaluate the performance of the hybrid LAES system, three performance indicators are considered: nominal-electrical round trip efficiency (neRTE), primary energy savings and avoided carbon dioxide emissions. Our results show that the hybrid LAES can achieve a high neRTE between 52% and 76%, with the maximum at ∼5 MPa. For a given size of hybrid LAES (1 MW×8 h), the primary energy savings and avoided carbon dioxide emissions are up to 12.1 MWh and 2.3 ton, respectively. These new findings suggest, for the first time, that small-scale LAES systems could be best operated at lower charging pressures and the technologies have a great potential for applications in local decentralized micro energy networks.

Convective flows along the bodies of animals

The production of high-quality livestock products is associated with the creation of optimal microclimate parameters in the premises for animals. Animals are a source of heat, and the convective flows formed along the body and the associated temperature mass-transfer fields, as well as the stresses arising under conditions of non-equilibrium interaction with the external environment, are of practical interest. In solving the stated problem of heat and mass transfer, we adopted an approximately convective flow consisting only of a vortex layer of free turbulence and considered the momentum equations of the lifting forces arising from heating and the amount of excess heat in the jet. It was assumed that the heat transfer per unit area of the warm surface is constant in height and length of the cylinder. As a result of a theoretical study of heat and mass transfer, the dependences of speed, excess temperatures, and convective flow were established. Analysis of the obtained dependences made it possible to conclude that the speed along the body increases with increasing mass of animals. This creates the prerequisites for using the heat generated by them to maintain the necessary temperature parameters of the air in the room. It is concluded that it is necessary to use only the upflows to provide animals with the necessary amount of oxygen. The resulting convective flow along the body of animals of different masses varies with a constant increase in the growth of animals. The upflows formed around the body of the animal are strong enough and lead to the rise of significant masses of air. Taking into account the physiology of cattle, it was concluded that the prepared air should be supplied to the heads of animals, as up to 30% of heat and carbon dioxide is released during exhalation, and animals’ bodies should be flooded with air in piggery.

Renewable Energy from Cooking Stove Waste Heat Energy using Thermoelectric Generator for Night Market Application

Malaysia night market normally operated along a temporarily closed road. No electrical power provided by the authorities and therefore hawkers need to prepare their own. Currently, they are working with gasoline-electric generator. On top of the cost incurred, they also need to consume exhaust gas and noise from the machine. Further, this situation will also affect customers. With a high percentage of the hawkers involve with cooking activities using the LPG gas stove, excess heat is one of the potential energy which can be converted into electrical energy using a thermoelectric generator (TEG). The aim of this study is to convert the excess heat available used to powered night market electrical facilities. A set of experiments was conducted utilizing five units of TEG connected in series to convert excess heat from a butane gas stove to electrical power. The temperature at both the hot and cold sides of the TEG was recorded used to analyze the effect of power produced. Two electrical parameters namely voltage and current outputs were measured used to calculate the electrical power generated. The analysis focused on the two main governing parameters namely temperature different and Seebeck coefficient toward power generated. It was found that only some amount of excess heat was converted which produced up to 46.8 mW electrical power. This is based on the high temperature recorded at the cold side of the TEG. The almost constant trend showed in temperature different was contributed to a small magnitude of the Seebeck coefficient and so for the power generated. The trend showed by the power generated was also almost constant even the temperature on the hot side keep increasing. The energy conversion process was considered success and can be further increased by increasing the number of TEG units used as well as by incorporating a cooling mechanism as practiced by many researchers.

Flexible integration of liquid air energy storage with liquefied natural gas regasification for power generation enhancement

Liquid Air Energy Storage (LAES) is one of the most promising energy storage technologies for achieving low carbon emissions. Our research shows that the LAES produces a considerable amount of excess heat that cannot be cost-effectively utilised in a standalone LAES system. On the other hand, the regasification of liquefied natural gas (LNG) often leads to waste of a large amount of high-grade cold energy. Therefore, this paper proposes the integration of the LAES with the LNG regasification process via a Brayton cycle (denoted as LAES-Brayton-LNG), where pressurized propane is used as both the heat transfer fluid and storage material for the LNG cold energy. The excess heat from the LAES works as the heat source and the waste cold from the LNG regasification as the cold source for the Brayton cycle. Such an integrated LAES-Brayton-LNG system does not need to change the existing LAES system configuration, and the LNG regasification process is independent of the LAES system, thus allowing operation flexibilities. Our analyses show that the flexibly integrated LAES-Brayton-LNG system achieves a system exergy efficiency of 57% and could improve the system exergy efficiency of the standalone LAES system by 14.4%. What’s more, it has an electrical round trip efficiency of ∼70.6%, which is ∼56.5% higher than that of the standalone LAES system. Hence, the proposed LAES-Brayton-LNG system is comparable with other large scale energy storage technologies in terms of the electrical round trip efficiency.

Parametric analysis on plastic deformation of materials during ultrasonic spot welding with different anvil geometries

Ultrasonic metal welding (USMW) has received noteworthy attention during recent years for its application to join lightweight materials. To improve the understanding of USMW process and to enhance the weld strength as well as quality, the present work is focused on the parametric study and its influence on the weld strength with various types of anvil tip geometries. It is observed that at higher weld time, an excessive amount of heat is produced at weld zone. Thus, a heavy plastic deformation occurs which is the major reason for over welding and lowering the weld strength. The temperature profiles for different types of anvils during the welding process are also examined at various weld conditions. The numbers of critical weld attributes are also identified to characterise the quality of weld formation over time. Microstructure study and microhardness measurement also have been employed to prove the severe plastic deformation in the interface layer as well as to establish a relationship between weld performance and physical weld attributes. As the weld time increases, the weld interface has been changed from planner to wavy morphology and the SEM micrographs proved the weld strength increments with the increase of waviness of the interface.

Progress towards Understanding Anomalous Heat Effect in Metal Deuterides

The present article summarizes anomalous heat events which were observed in a large number of electrolysis experiments using heavy water and palladium-based cathodes. The amount of excess heat produced by some of these experiments is too large to be accounted for by any known chemical processes. It was found that events of the anomalous heat effect (AHE) are accompanied by increased cell voltage during electrolysis and that there are characteristic cathode surface morphologies which are associated with excess heat events. AHE has been observed during electrolysis following dynamic stimulation of the cell by time-dependent electrolytic currents (SuperWaves) and ultrasonic excitation. Past experiments have increased our understanding of the anomalous heat effect in the palladium-deuterium systems, but there is much left to be learned.

Evaluation of opportunities for heat integration of biomass-based Fischer–Tropsch crude production at Scandinavian kraft pulp and paper mill sites

This study investigates heat integrated production of FT (Fischer–Tropsch) crude, where excess heat from the FT crude plant is delivered to a typical Scandinavian pulp and paper mill that produces fine paper. The sizes of FT crude plants are quantified, when the amount of excess heat from the FT plant exactly matches the heating demand otherwise satisfied by the bark boiler at the mill, considering a number of development pathways at the mill, including various degrees of steam savings and biorefinery options, such as lignin extraction. Performance of integrated production is compared with that of an FT stand-alone plant on the basis of wood fuel-to-FT crude efficiency, GHG (greenhouse gas) emissions balances and FT crude production cost. The results show that there exists a heat integration opportunity for an FT crude plant ranging from 0 up to 350 MW (LHV) of wood fuel depending on the development pathway for the mill. The results indicate higher overall efficiency and a generally lower production cost for the heat integrated, co-located production. Heat integrated production has a larger potential to contribute to GHG emission mitigation, assuming a future generation of grid electricity emitting equal to or less than an NGCC (natural gas combined cycle) power plant.

Utilization of excess heat in the pulp and paper industry––a case study of technical and economic opportunities

Newly developed methods and tools based on pinch technology are used in a case study to investigate the potential and economy of using excess heat for pre-evaporation of chemo thermo mechanical pulp effluent and heat pumping in an integrated pulp and paper mill. The new tools give information about the system that traditional pinch tools such as the grand composite curve or the composite curves would not reveal. For example, the highest temperature levels possible where excess heat can be released are identified together with the amount of excess heat at each temperature level. The new curves are also able to provide information about where heaters and coolers are placed in an existing system. The matrix method has been used successfully in order to find an economically feasible heat exchanger network retrofit for the release of the excess heat found with the curves. The results of the case study show that a pre-evaporation plant can be integrated with the overall process with just a few modifications in the existing process. There are also opportunities for heat pumping in the system. Both projects have a pay-back period shorter than required for implementation.

Tritium Generation and Large Excess Heat Evolution by Electrolysis in Light and Heavy Water-Potassium Carbonate Solutions with Nickel Electrodes

The generation of tritium was quantitatively measured in an electrolytic cell with a nickel cathode and a platinum anode in potassium carbonate-light and heavy water solutions. Simultaneously, the evolution of a large amount of excess heat (70 to 170{degrees} for the input power) was observed during electrolysis of these solutions. The tritium generation by electrolysis provides some of the most conclusive evidence for so-called cold fusion, along with the calcium generation described in a previous paper. On the basis of the current experiments and the knowledge of the knetics of a hydrogen evolution reaction in an alkaline solution, the nuclear reactions taking place are worth mentioning. 11 refs., 1 fig., 2 tabs.

Shape Factors for Cooling Lakes

The design of cooling lakes for stream electric power plants requires the determination of expected temperature distributions that result from surface heat dissipation. The designer has the problem of determining the effective surface area and how it might be changed by intake and discharge locations, plant size, and condenser cooling water pumping rates. The effective surface area depends on the shape of the lake, the direction of the main flow path and the amount of excess heat that is mixed into the tributary sidearms. These factors can be evaluated in terms of a shape factor derivable from heat budget relationships applied to each segment of the cooling lake. The derivation of the shape factor is presented and its evaluation for different intake and discharge configurations is illustrated. The use of the shape factor in temperature prediction relationships for different types of lakes is also presented.