Journal of Energy Engineering

Block ramp structure can be a part of a layout of microhydel scheme, depending upon the conditions of topography and geology at the site. Block ramps transmit the flow of stream to a lower level inducing kinetic energy dissipation. Block ramps consists of base material in the form of stones inducing roughness whereas stepped chutes are overflowing structures which consists of step configuration at the bottom of the flowing stream. As there is a common objective of energy dissipation of flow, the geometrical elements of block ramps and stepped chutes are considered to be comparable under similar hydraulic conditions of skimming flow. This paper analyzes the experimental results on both these structures. A mathematical model in dimensionless form is proposed herein, which correlates the representative bed material size of block ramp with the step height of stepped chute. This correlation is expected to facilitate the design of block ramps using the literature available on stepped chutes.

A number of compounding issues currently encourage a different management strategy of produced water from oil, gas, and coal bed methane. Environmental and economic constraints make it desirable to deploy water and energy resources efficiently and effectively to meet the demands of our populace while maintaining and supporting environmental resources. The following paper will outline one strategy to put some of the onshore produced water to beneficial uses. In this approach, the produced water is first cleaned and then used to supply water for pumped hydroelectric energy storage (PHS) to deploy electric energy on demand, and finally release that water back to the watershed or appropriate application. The primary purpose of this work is to suggest that produced water and PHS may complement each other. Additionally, it is suggested that revenue from energy storage can help provide for the cost of treatment of produced water. Once treated produced water could be put to additional uses with the potential to also bring in revenue.

With increasing demand for power and with shortages envisioned especially during the peak load times during the summer, there is a need to boost gas turbine power. In Taiwan, most gas turbines operate in combined cycle mode for base load. Only a small portion of gas turbines operates in simple cycle mode for peak load. To prevent the electric shortage due to derating of power plants during hot days, the power augmentation strategies for combined cycles need to be studied in advance. As a solution, our objective is to add an overspray inlet fogging system into an existing gas turbine-based combined cycle power plant (CCPP) to study the effects. Simulation runs were made for adding an overspray inlet fogging system to the CCPP under various ambient conditions. The overspray percentage effects on the CCPP thermodynamic performance are also included in this paper. Results demonstrated that the CCPP net power augmentation depends on the percentage of overspray under site average ambient conditions. This paper also included CCPP performance parametric studies to propose overspray inlet fogging guidelines for combined cycle power augmentation.

In this study, an experimental study has been performed for a natural gas fueled boiler operating at 42,000-kPa pressure and 713.15-K temperature with a nominal capacity of 33.33 kg/s to find improvement in the boiler efficiency. Temperature, pressure, velocity, and gas emissions measurements have been made and energy, mass balances, and exergy analysis have been formed. Then, efficiency of boiler, potential energy saving options and saving quantities, investment costs, and payback period for normal operating conditions have been calculated. From the measured data, the boiler and exergetic efficiency were calculated as 88.28 and 36.7%, respectively. It is seen that the main efficiency losses are leakage of air in the rotary type air heaters, operation of the boiler at high excess air/fuel ratios, operation of the boiler under the rated load, surface thermal losses, and high flue gas temperatures. The largest part of the boiler efficiency losses is due to the air leakage in the rotary type air heater. Due to air leakages, the load of the induced-draft fan increases and prevents the boiler to reach its normal boiler capacity. It has been calculated that if air leakage in rotary type air heater is reduced to acceptable limits (10%) in practice, boiler steam production capacity will be increased by 34.2% from 24.44 to 32.8 kg/s. Implementation cost is required only for reducing air leakages in the rotary type air heater and surface thermal losses. The investment cost for reducing air leakage in the rotary type air heater to the acceptable limits (10%) is between $600,000 and $700,000. Under these circumstances, the payback period of this investment cost is about 15 months.