Mary Jane Hale

Advanced Thermal Storage Fluids for Solar Parabolic Trough Systems

It has been established that the development of a storage option and increasing the operating temperature for parabolic trough electric systems can significantly reduce the levelized electricity cost (LEC) compared to the current state of the art. Both improvements require a new heat transfer fluid that must have a very low vapor pressure at the hot operating temperature and combined with a high thermal stability, higher than 450°C. Further, the piping layout of trough plants dictates that the fluid not be allowed to freeze, which dictates the use of extensive insulation and heat tracing unless the fluid has a freezing point near 0°C. At present, it seems likely that this “ideal” fluid will have to be found among organic rather than inorganic salts. We are therefore investigating the chemical and thermal properties of ‘room temperature ionic liquids’ (RTILs) that hold much promise as a new class of heat transfer or storage fluids.© 2002 ASME

Performance of a Zero-Energy House

A comparative study is reported to measure the actual performance of a zero-energy house (ZEH) of typical tract design. Ideally, a ZEH produces as much energy as it consumes in a years time. Two identically sized tract houses (149.6 m 2 (1610 ft 2 ) ) were constructed side by side in southwest Las Vegas, NV One house is used as a base line (standard comparison) house and was built using conventional construction techniques. The other house, the ZEH, employs many energy saving features, solar power generation, and supplemental solar water heating. Both houses have been equipped with a network of sensors that measure virtually every aspect of energy usage in each home. Initially, both houses have been utilized as model homes in a tract housing development, so it was reasonable to believe that both experienced similar and consistent usage. Performance data are logged and are posted on the web. This paper describes the differences in construction details between the two houses. Results of monitoring are presented that contrast the performance of the two houses.

Advanced Parabolic Trough Field Testing: Real-Time Data Collection, Archiving, and Analysis for the Solargenix Advanced Parabolic Trough

Solargenix Energy is currently constructing a 64-MWe parabolic trough solar plant in Eldorado Valley, Nevada, just south of Las Vegas. As part of the preparation for construction and operation of the new utility-scale solar plant, Solargenix has collaborated with UNLV and NREL to build a collector test row. The test row is serving as a platform for field testing advanced parabolic trough components before their large-scale deployment. The test row consists of two Solargenix Solar Collector Assemblies (SCAs); each SCA has 12 collector modules (space frames and mirrors). This facility has been used to field test new Solargenix designs for first and second generation collector space frames, advanced reflectors, advanced local controllers (AdLoCs), a hydraulic-based drive system, receiver support arms, low-cost injection-molded bearings, ball joints and collector support pylons. The test-row facility also has equipment for monitoring the following weather data: direct normal irradiance, dry bulb temperature, relative humidity, wind speed and precipitation. Data logging equipment is used to record and track weather data as well as SCA parameters. Site instrumentation is solar-powered (photovoltaics) and uses cellular technology to transmit data to a web-based data collection system. This paper describes construction of this facility, the installation of the data-collection system and some data collected to date.Copyright

Monitoring of a Zero-Energy-House

A comparative study is being conducted to measure the actual performance of a Zero Energy House design. Ideally, a zero energy house produces as much energy as it consumes in a year’s time. Two identically-sized houses (1610 sq ft), constructed side-by-side in southwest Las Vegas, Nevada, are equipped with a network of sensors that measure every aspect of energy usage in each home. One house is used as a baseline (standard comparison) house and was built using conventional construction techniques. The other house, the Zero Energy House, employs many energy saving features, solar power generation, and supplemental solar water heating. Both houses are utilized as model homes in an actual housing development, so it is reasonable to believe that both will experience similar and consistent usage. The data logged onsite are automatically collected every day (in an almost real-time basis) and sent via telephone connection to the Center for Energy Research at UNLV for analysis. Results are posted on the web. This paper describes the differences in construction details between the two houses. It also gives a summary of the ways the performance data are being acquired and processed. Finally, the methods used to represent the data are outlined.Copyright

Southern Nevada Renewable Resource Assessment

University of Nevada, Las Vegas Renewable Energy Center (UNLV-REC) currently monitors three meteorological stations in southern Nevada under the direction of the National Renewable Energy Laboratory (NREL) and is funded by the Nevada Southwest Energy Partnership (NSWEP). The three station locations are Eldorado Valley, UNLV-REC Solar Site, and Nevada Power Company Clark Station. The installation dates for each of the locations were October of 2004 for Eldorado Valley station, August of 2003 for the UNLV-REC Solar Site, and March of 2006 for the Nevada Power Clark Station. Publicly available data from each site have been archived since installation completion. This paper discusses the installation of the equipment for each site and images of the setup. The data that is being collected between the sites is also compared. Data comparisons between the sites include net monthly solar energy; monthly peak direct normal irradiance (DNI), average daily wind speed, monthly wind roses, and average monthly dry bulb temperatures. The recently measured data is also compared to resource maps developed by NREL and to TMY data. With these meteorological resources, microclimatic variations can be studied for the area and used as a renewable energy resource for renewable installations in southern Nevada.Copyright

Field Testing and Performance of an Amonix Multi-Junction Cell Module at the University of Nevada Las Vegas

This paper discusses the installation, operation, and performance of a high concentration photovoltaic single-plate, multi-junction module developed by Amonix and installed at the Center for Energy Research at the University of Nevada, Las Vegas (UNLV). The paper discusses the objectives and goals of this project and describes the principal of the Fresnel optics, the module, and how it was attached to the Amonix 25-kW unit located at the UNLV Center for Energy Research. Also described are how the module is connected to a load and the measurements taken. Data is presented in the paper showing the module has produced power for over 2200 hours at a power efficiency of 26% to 28.6%. Data is also presented showing the next generation single-plate, multi-junction module achieving an efficiency of nearly 30%.Copyright

Operation and Performance of the Amonix High Concentration Photovoltaic System at the University of Nevada, Las Vegas During the Second Year of Operation

This paper discusses the operation and performance of the Amonix High Concentration Photovoltaic (HCPV) System at the Center for Energy Research at the University of Nevada, Las Vegas (UNLV) from the start of operation in March 2004. The objectives and current status of this two-phase project are discussed, including: a brief description of the system, daily operation, and system maintenance. Also included are: the performance data of Phase I and Phase II showing a typical daily power profile, the accumulated energy generated, daily peak power and daily generated energy, normalized peak power, normalized energy performance, and an estimate of the annual energy performance based upon the actual measured energy during the operation of the system. System reliability data, in terms of mean-time-between-failure, are also presented.Copyright