Journal of Energy Engineering

Corporate governance has emerged as a topic of significant importance, particularly in the aftermath of the Enron scandal. Undoubtedly, the renewed scrutiny of this entity is not without justification. Enron’s failure is largely attributed to a breakdown of corporate governance with the inability, or unwillingness, of the board of directors to hold management accountable on behalf of the shareholders. Meanwhile, the academic and popular literatures have yet to provide unequivocal guidance as to the appropriate modus of operandi in the boardroom. Based on survey and interview results, this paper provides some suggested practices regarding the proper functions, optimum configurations, and appropriate incentive schemes of the boardrooms belonging to the energy industry. The importance of the energy sector stems from its prominent role as a main contributor to the production of goods and services. The guidelines presented in this study would enable the boardroom to be vigilant and adopt preventive measures not just in crisis situations, but also continually.

This paper presents an optimization model and solution procedure for planning investments in gas distribution networks for residential customers. The situation can be considered a capital budgeting problem under uncertainty. There is uncertainty about whether a potential customer will convert to gas service if a distribution main is built, the revenue generated if the household does convert, and the cost of constructing the main. A fixed annual budget is allocated to a set of discrete, competing projects over time. The allocation is done by maximizing the expected net present value (NPV) given the decision-maker’s risk preferences. The probability distribution of the NPV for each competing project is created from two statistical models. A binary probit model is used to estimate the probability of conversion for a potential customer. A random effects regression model is used to estimate the revenue generated should a particular potential customer switch to gas. A rollout value greedy heuristic was devised to solve the resulting optimization formulation. Two case studies based on data from a large gas company illustrate the analysis.

A three-dimensional computational fluid dynamics (CFD) model has been constructed to simulate fluid flow in two commonly used pipe fittings: An elbow and a T-joint using the STAR-CD code. A $k$ - $\epsilon$ Chen model suitable for high $\mathrm{Re}$ numbers flows was used for that purpose. Two flow configurations were used for the T-joint. In the first, the flow enters through the middle leg of the fitting; and in the second, the flow enters from one of the ends and exits from the other two outlets. The $\mathrm{Re}$ number for the flow simulations was varied between $0.78\times {10}^5$ and $1.56\times {10}^5$ to simulate a variety of flow conditions with approximately six uniformly distributed values of $\mathrm{Re}$ numbers chosen between these limits. The velocity profile indicated some flow reversal regions near the inner radius and some high velocity regions near the outer radius downstream of the elbow. Pressure profiles showed significant changes from a high value on the outer radius to a low one on the inner radius. The T-joint flow case into the center leg showed recirculation regions immediately downstream of the elbows, and high velocity values just downstream from the stagnation zone. The pressure profile for that arrangement showed significant pressure gradients across the flow area before the flow splits into the two legs. For the straight leg inflow case, the velocity shows flow reversals in the $90°$ bend and the pressure drop is large along the $90°$ bend as opposed to the straight leg. The simulation uses a flow split of 50–50 between those legs. The simulations agree reasonably well with recently published experimental results. For the T-joint and with the flow introduced through the straight branch (T-joint-Inlet Case B), the difference in pressure drop for the straight run and branch flow was 7.76% and 18.38%, respectively. For the elbow, the difference was 8.1% lower than the experiment. Comparisons were also made with values supplied by the ASHRAE Handbook for $K$ values, i.e., minor loss factors.

It is accepted that fossil fuel is the major source of energy in use today. The technology to use this fuel is well-developed and relatively safe. However, there are two fundamental problems facing the industry that is so dependent on this type of fuel. One, it is a limited resource with only decades of life left. Second is the pollution resulting from its use, primarily the $\mathrm{C}{\mathrm{O}}_2$ greenhouse gas generated, and acid rain from $\mathrm{N}{\mathrm{O}}_x$ and $\mathrm{S}{\mathrm{O}}_2$ . Until suitable substitutes are found, developed, and implemented, the next best option is to reduce the consumption of the fuel through higher efficiency. Recent research projects with regard to environmental issues send a clear signal to both governments and the energy manufacturing industry that they need to act quickly in order to sustain the environmental conditions. Cogeneration is a technology which can achieve this, but it is important that financial and taxation systems are designed and implemented in a way that recognizes a broader scope for accountability of the needs of industry. Due to increase in the world economy there is a need for further technological progress and environmental legislation. This paper describes a potential fiscal model which could be used to encourage the responsible use of modern clean cogeneration plants to reduce the environmental impact and to allow some political influence over fuel use.

Three identically oriented homes were used for the study. Two of the homes were identically constructed using wood frame/stucco construction while the third used a wall of sandwiched Styrofoam in between concrete layers. It was found that the concrete house on the average consumed about 15% less energy for HVAC operation than the wood frame houses. Also the photovoltaic array placed on the roofs of two of the houses indicated a reduction in electrical energy consumption from the grid of about 20% of the HVAC electrical energy consumed. TRACE-700 simulation runs were made on both types of houses to determine the design cooling load for each of the houses and the total consumed electrical energy for each house over the whole year on a monthly basis. It was found that in the summer a 20% reduction of electrical energy for HVAC is predicted due to the use of the concrete house as compared to the wood frame homes. In addition a linear correlation was found to represent reasonably well the variation of the daily kilowatt hour versus the daily degree day value for a typical summer month in the Las Vegas, Nev. valley for all three houses. The slope of that line for the concrete home was about 24% less steep than the line for the wood frame construction confirmation in part theoretical calculations that this wall construction is more energy conserving than the base case.

It has been recognized in recent times that air-cooled condensers (ACCs) are environmentally preferable to the traditional water-cooled condensers for rejecting heat in combined-cycle power plants (CCPPs). However, a drawback of ACCs is that their performance can decline with increasing ambient air temperature. A new approach is proposed in this paper that has the potential to alleviate this drawback of ACCs. In this approach, a chilled-water thermal energy storage system (TES) is used to precool the inflow air to the ACC whenever the ambient air temperature increases above the design air inlet temperature. The temperature of the TES system is maintained by an absorption refrigeration system (ARS) driven by low-quality waste heat from the CCPP. A process model integrating the CCPP with the ARS and the TES has been developed to optimize the volume of the TES. A $500\mathrm{MW}$ CCPP with steam turbine net output of $170.9\mathrm{MW}$ was chosen to evaluate the application of this approach for a power plant to be located in southern New Mexico. This analysis showed that a tank volume of $\mathrm{4,500}{\mathrm{m}}^3$ will be required to maintain the air temperature at the inlet to the ACC at the design value of $20°\mathrm{C}$ throughout the year. Simulations under ambient air temperatures up to $40°\mathrm{C}$ indicated that the proposed system is capable of maintaining the rated net power output of the plant with minimal fluctuations. Simulations also showed that TES tank volume is most sensitive to the design air inlet temperature to the ACC—an increase of this temperature by $1°\mathrm{C}$ can result in at least 25% reduction in the volume.