THE CENTER FOR ENERGY RESEARCH
BACKGROUND
This Center is a focus area for research, information exchange, and education in energy topics. Topics of particular interest to our geographical region are included as are more general topics. In the former category, solar energy utilization schemes, arid regions energy systems (e.g. dry cooling considerations), advanced cooling concepts (e.g. refrigeration systems that do not use CFCs), and nuclear waste issues are included. In the latter category are conventional power generation systems, energy conservation devices and systems, and environmental control issues for energy systems. The Center serves as a generator and catalyst for ideas, a stimulus for interdisciplinary cooperation, and a facilitator for commercialization.
The Center acts as a base for bringing together people from a variety of disciplines to work on specific problems of interest. These problems may be defined within the Center without particular knowledge of funding, drawing upon strengths of the people involved. People within the Center then seek possible funding sources for this work. Alternatively, funding opportunities may become known to Center personnel, and focus groups will be formed to attack these problems.
Information exchange and educational activities are an integral part of the function of the Center. To cite examples of each of these, a Solar Energy Interest Group has been formed under the auspices of the Center. This group sponsors discussions of solar applications, and hosts professionals in the field for visits and seminars to UNLV. A second type of function is the stimulus for formal class offerings. Under the encouragement of Center personnel, an class offering, EGG 150/450, Introduction to Solar Energy Applications, is being offered at UNLV. Faculty from Mechanical Engineering, Electrical Engineering, Civil and Environmental Engineering, Environmental Studies, Architecture, and Political Science give various portions of the course.
While the Center is broad in its scope and welcomes interactions with any interested party within the University and Community College System of Nevada as well as laboratories elsewhere, the primary thrust is located in the Howard R. Hughes College of Engineering at UNLV. Close affiliations exist with the Architecture program at UNLV. The Director of the Center reports to the Dean of the Howard R. Hughes College of Engineering.
CURRENT RESEARCH
1. Hydrogen/Electric Hybrid Bus
This project, under contract with the Nevada Operations Office of the US Department of Energy, is to develop a modified bus into a test-bed for advanced hybrid concepts. Work is taking place related to control strategies and systems, battery systems, safety sensors and their operations, hydrogen fueled engine development, development of supercapacitor regenerative braking systems and several other aspects. A photograph of the exterior of the bus is shown in Figure 1. In the initial configuration, the bus was modified from a pure electrically-driven configuration to one where a hydrogen fueled engine/generator and storage system was added. The generator was used to recharge batteries on board as needed. Hydrogen was stored in metal hydride beds.
Current modifications to the previous system taking place involve the development of a new engine as well as the addition of a better controlled regenerative braking system and high pressure hydrogen tanks. General modifications are being made to enhance the ability to incorporate a variety of prime movers and other components as may be desired in the future.
Figure 1. The Hydrogen/Electric Hybrid Bus currently undergoing development in Las Vegas.
Figure 2. The UNLV hydrogen-fueled engine being evaluated at Kells Automotive in Las Vegas.
The engine that is being used for this application is a modified Chevrolet 454 cu in V-8 with a special fuel injection system. In the bus application the engine operates at a constant speed so the ìtuningî of exhaust and intake channels can be used. A special cam was designed for this engine, and attention was given to making the intake ports allow larger flow with lower pressure drop. Figure 2 shows a photograph taken at Kellís Automotive of Las Vegas, where the engine was evaluated..
2. Development of Second Generation PV Systems for Remote Environmental Monitoring
Environmental monitoring is taking place in a variety of locations on the Nevada Test Site (NTS) located north of Las Vegas. Many places where monitoring is desired are remote from any electrical power sources but require continuous power for operation. An example of one of these systems is shown in Figure 3. For these applications, photovoltaic power generation systems have been shown to be quite effective. However, these systems tend to be quite expensive.
Figure 3. An example of an existing system used for remote monitoring of air quality at the NTS. These systems operated quite well but have a high initial cost and are costly to relocate.
A ìsecond generationî system design has been developed and built for this. This was done by carefully considering various component efficiencies and sizing components so overall efficiency is maximized. Included is the substitution of a DC motor drive for the environmental monitoring system. In accomplishing this, the physical size of the unit was reduced by nearly 50% with associated decreases in cost and enhanced ability to move the system. Two people can now move the system quite easily on a custom trailer without other special equipment. The first prototype, built by Direct Power and Water of Albuquerque for the Corporation for Solar Technology and Renewable Resources, is shown in Figure 4 undergoing evaluation at the Department of Energy Nevada Operations Office in Las Vegas.
Figure 4. The second generation PV power supply for use in remote environmental monitoring is shown undergoing evaluation at a DOE facility. In this picture the trailer has been moved out from under the PV system.
An additional component of this work will make a PV system available to 7-12 grade schools in the area for curricular use in science, environmental, and technology classes.
3. Technical Support for Marketing of Solar Water Heaters
A local public, non-profit organization CSTRR (the Corporation for Solar Technology and Renewable Resources), under contract to the US Department of Energy, is working with a large national builder and the local electrical utility to market solar water heating systems. Pulte Homes, the builder involved with this effort, has a significant presence in both the Las Vegas and Phoenix housing markets as well a numerous other nationwide. As part of the program, Pulte is installing water heaters on new homes at the buyersí option. The CER at UNLV has served in a technical assistance role in the project, particularly focusing on the performance effects on the economics of the systems. Candidate water heaters have been mounted on the roof-top CER laboratory at UNLV. Prescribed water draw cycles have been programmed for the systems, and auxiliary energy required to maintain water temperature is determined. Figure 5 shows three water heaters mounted in the roof-top array. Shown in the background is the Arid Regions Laboratory where roofing/insulation tests have taken place. Figure 6 shows a water heater associated with one of the solar collectors, and located physically below the solar collector, as well as the water heater used as the control (no solar connection). One of the Pulte model homes that incorporates solar domestic water heating is shown in Figure 7.
Figure 5. Three solar water heating collectors mounted on the roof-top laboratory of the Center for Energy Research. Evaluation is taking place as part of the CSTRR project for solar water heater marketing. Shown in the background is the world-famous Las Vegas Strip.
Figure 6. Two of the electric water heaters used in the CSTRR project are shown. The one on the left is connected to a solar water heater through an antifreeze fluid loop, and the one on the right is the control water heater (no solar heating).
Figure 7. A solar domestic water heating panel is shown on a Pulte Homes model in southeastern Las Vegas.
System Analysis of Storage in Trough Solar Thermal Power Plants
In a new program funded by the US Department of Energy, a thermal-systems analysis will be performed of the effects of adding storage to trough-type solar thermal power plants. Solar plants of the trough type have generated the most amount of solar electricity of any type in the world. See Figure 8 as an example of such a plant. The technology has been well developed, but the plants have relied upon a conventional fuel to cover periods when the sun was not shining. With developing concerns for decreasing the amount of greenhouse gases generated, a new effort is being made to incorporate thermal storage in trough-type power plants.
Our work involves two facets. In one, we are working closely with the National Renewable Energy Laboratory (NREL) on screening possible storage materials. NREL has a significant program underway related to organic salt materials. We will assisting them with identifying desirable ranges of key properties so that they can focus their efforts within the range of possibilities.
In a second thrust we will be performing simulations on trough power systems that incorporate storage. This work will use a modified form of the code TRNSYS. This code has been historically been used for building applications, but it is being adapted to trough system analysis. With a functioning model, we will be able to assess the cost/benefit ratio for the use of various kinds of storage materials.
Figure 8. A picture of a trough-type solar system is shown.
5. Technical Support for Tunnel Burn of Military Materials
As part of the US demilitarization efforts, various aged ordnance and solid rocket fuel are being burned. While some of this is being accomplished via open fires, a set of experiments is taking place in a tunnel at the Nevada Test Site, north of Las Vegas. Gases of combustion are collected and cleared before being released to the atmosphere.
The Center for Energy Research and the Harry Reid Center for Environmental Studies at UNLV are working under subcontract from a consortium of US National Laboratories to lend technical support. Work that has taken place, or is taking place, in the Center for Energy Research is related to performing some numerical simulations related to temperature and pressure profiles within the tunnel, as well as predicting the vaporization of condensed organic materials from the wall that were left in earlier tests.
Figures 9 and 10 show an example of a set of rocket engines before burning, as well as after burning. Note that the rocket cases are cut longitudinally with explosive as part of the burning process.
Figure 9. An example an arrangement in a tunnel at the NTS of rocket motors prior to being opened by explosive and then burned.
Figure 10. This is the situation after burning of the rocket engines shown in Figure 9.
Contacts:
Robert F. Boehm, PhD, PE
Director, Center for Energy Research
UNLV Box 454027
Las Vegas, NV 89154-4027
702/895-3936
boehm@me.unlv.edu
Yahia Baghzouz, PhD, PE
Co-Director, Center for Energy Research
UNLV Box 454026
Las Vegas, NV 89154-4026
702/895-0887
eebag@ee.unlv.edu