Low-potential Sources Research Articles

Operating characteristics of a bladeless turbine for irrigation purposes

Irrigation and pumping systems are still important issues in agriculture. There are many places on the Earth where water needs to be pumped, however no energy sources are available to power the pumps. The bladeless turbine offers a possible solution. This machine can utilize even low-potential sources of water-borne energy working as autonomous energy sources. The turbine has been developed only recently and therefore no comprehensive operating characteristics has existed as yet. The article summarizes the results of experimental measurements carried out on the SETUR DVE 120, a commercially available bladeless turbine sold in a monoblock together with an electricity generator. "User" characteristics have been created from the measured data: dependence of output electrical power and the efficiency of the set on speed, etc.

Assessment of the acid mine drainage potential of waste rocks at the Ak-Sug porphyry Cu–Mo deposit

This investigation was conducted using waste rock materials from the Ak-Sug porphyry Cu–Mo deposit, which is located in the northeastern region of the Tuva Republic in Russia. To predict the formation of acid mine drainage, the waste rocks were investigated using X-ray fluorescence with synchrotron radiation spectroscopy (XRF-SR), X-ray diffraction analysis (XRD), microscopy, and aqueous leaching and intensive oxidation experiments. In addition, the sulfide and carbonate contents were determined to calculate the net acid potential. The waste rock materials were generally low potential sources of acid mine drainage. Only 26% of the rock samples produced acidic effluent following long-term storage. In the results that were obtained from the complete oxidation of the waste rocks, the drainage solutions that were generated had elemental concentrations that exceeded the following MPC (Maximum Permissible Concentrations): Fe — 560 times; Cu — 43 times; Mn — 23 times; Mo — 20 times; As — 50 times; Cd — 19 times; Sb — 17 times; Se — 7.5 times; and Co — 4.5 times. Arsenic was of particular concern in the waste rocks due to its high concentrations, with more than 50% of the samples containing arsenic at concentrations of more than 10g/t and with a maximum concentration of 450g/t. Arsenic can leach rapidly in neutral and sub-alkaline solutions (which were dominant in the aqueous extracts of the investigated rocks).The change of the element species in solutions was shown by the WATEQ4F calculations. Occurrences of sulfate complexes of the elements resulted in higher concentration of Al, Fe and Mn in the solution. The most environmentally hazardous species Me(H2O)62+ of copper, zinc, and cadmium begins predominate in drainage solutions during a long storage of the sulfide-containing wastes.WATEQ4F equilibrium calculations indicated that in acidic solutions the partial dissolution of the hydroxides and oxides of Al, Fe, and Mn, and the substantial desorption of the potentially toxic elements from their hydrated surface and crystal lattice will occur.These results will be used for modeling and designing waste dumps, which could prevent acid production.

Changes in energy and temperature in the ground mass with horizontal heat exchangers—The energy source for heat pumps

This article addresses soil temperature analysis, heat flows and energy transferred from the soil massif via a linear horizontal heat exchanger and horizontal heat exchanger of Slinky type. Heat exchangers are used as low-potential sources of thermal energy for heat pumps. Both exchangers were compared in terms of their influence on the soil massif temperature in the exchanger area, and on the exchanger power output. The exchangers were evaluated in the heating periods of 2011–2012, 2012–2013 and in the exchanger stagnation period of 2011. The linear heat exchanger seems to be more suitable as a low-potential power supply for heat pumps. The average temperatures of the soil massif in the exchanger areas were positive in both heating periods and the temperature was higher at the linear exchanger. The temperatures of the heat-transfer fluid exiting the exchangers were positive and the linear exchanger temperature was higher. The temperatures of the heat-transfer fluid entering the exchangers were identical, and were negative only in exceptional cases. The natural energy recovery capabilities of the ground massif during the exchanger stagnation period were confirmed. The specific heat transferred from the ground massif was significantly lower with the linear exchanger than with the Slinky type.

Development of complex method of intellectual control in cogeneration systems

It is developed a complex method for controlling the operation of the cogeneration system using such dynamic subsystems as: electric accumulator battery, heat electric accumulator; electric accumulator battery, heat pump, which uses a recover heat as a low-grade energy source, which changes as the production of energy and its consumption as a part of a cogeneration unit; biogas plant, heat pump, which uses the fermented wort as a low-potential power source, electric accumulator battery and heat electric accumulator. Predictive information obtaining for decision-making under conditions of not matching production and consumption of electric power and heat can reduce the cost of energy production and emissions of carbon dioxide by 15 %. Biogas saving, for example, by fermentation of 60.2 t/day with increasing marketability of raw biogas unit at 10-15 % is 49400 m3/year.

Dissipative processes during the nonequilibrium phase transformations in martensitic thermoelastic alloys

Martensitic thermoelastic transformations are considered under nonequilibrium conditions, where a system nonmonotonically tends toward a stationary process. The specific features of a phase transformation are experimentally studied on molecular models under these nonequilibrium conditions. A resonance mode of the phase transformation, which can increase the process rate by an order of magnitude without increasing the heat source temperature, is found. The dissipative processes that occur under the monotonic and resonance conditions of martensitic thermoelastic transformations are estimated. The resonance mode is shown to be accompanied by negative entropy production and to demonstrate the self-organization of the system. These results can be used to design materials and techniques for the processing of low-potential heat sources.

Experimental studies on R134a-DMAC hot water based vapour absorption refrigeration systems

The objective of this paper is to present an experimental study on environment friendly vapour absorption refrigeration system of 1 kW capacity using R134a-DMAC as the working fluids. The system is designed and tested for various operating conditions using hot water as heat source. In this paper, performance of the fabricated system are outlined with respect to various operating parameters such as heat source, condenser, absorber and evaporator temperatures. The result indicates that at the sink and source temperatures of 30 and 80 °C respectively and a typical heat input of 4 kW, the system attained steady state in two hours. For this system an actual COP of 0.25 to 0.45 was obtained under the tested conditions. The study reveals the feasibility of using R134a-DMAC as working fluids in the absorption machines using low potential heat sources for various applications.

03/01862 New possibilities for energy production from renewable low-potential sources: Samkhan, I. I. Applied Energy, 2003, 74, (1–2), 203–209

03/01862 New possibilities for energy production from renewable low-potential sources: Samkhan, I. I. Applied Energy, 2003, 74, (1–2), 203–209

New possibilities for energy production from renewable low-potential sources

We examine an opportunity for increasing cyclic process efficiency at the expense of taking into account speeds and times of running processes. We consider dynamic equilibrium systems, in which the equations of state include both parameters of the system and environment. At low flow speeds, conventional quasi-static methods apply. At high speeds, new regenerative cycles become possible. This requires the introduction of an extended interpretation of the second law of thermodynamics. This involves specifying the performance of a cycle by the relative difference of temperatures of the working fluid (but not of thermal sources) at the upper and lower temperature levels of the cycle.