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Simple Procedure for Predicting Long-Term Average Performance of Nonconcentrating and of Concentrating Solar Collectors

Description: The Liu and Jordan method of calculating long term average energy collection of flat plate collectors is simplified (by about a factor of 4), and generalized to all collectors, concentration and non-concentrating. The only meteorological input needed are the long term average daily total hemispherical insolation H/sub h/ on a horizontal surface and, for thermal collectors the average ambient temperature. The collector is characterized by optical efficiency, heat loss (or U-value), heat extraction efficiency, concentration ratio and tracking mode. An average operating temperature is assumed. Interaction with storage can be included by combining the present model with the f-chart method of Beckman, Klein and Duffie. Formulas and examples are presented for five collector types: flat plate, compound parabolic concentrator, concentrator with E.-W. tracking axis, concentrator with polar tracking axis, and concentrator with two axis tracking. The examples show that even for relatively low temperature applications and cloudy climates (50 degrees C in New York in February), concentrating collectors can outperform the flat plate. The method has been validated against hourly weather data (with measurements of hemispherical and beam insolation), and has been found to have an average accuracy better than 3% for the long term average radiation available to solar collectors. The suitability of this method for comparison studies is illustrated by comparing in a location independent manner the radiation availability for several collector types or operating conditions: two axis tracking versus one axis tracking; polar tracking axis versus east-west tracking axis; fixed versus tracking flat plate; effect of ground reflectance; and acceptance for diffuse radiation as function of concentration ratio.
Date: June 1978
Creator: Collares-Pereira, Manuel & Rabl, Ari
Partner: UNT Libraries Government Documents Department

Design of a System using CPC Collectors to Collect Solar Energy and to Produce Industrial Process Steam

Description: A system has been designed to use CPC collectors to collect solar energy and to generate steam for industrial process heat purposes. The system is divided into two loops with the collectors in the collector loop to operate a pre-heater and the collectors in the boiler loop to heat water to elevated pressures and temperatures. A flash boiler is used to throttle the heated water to steam. Two types of CPC collectors are chosen. In the collector loop the CPC collectors are fitted with concentric tube receivers. In the boiler loop the collectors employ heat pipes to transmit heat. This design is able to alleviate the scaling and plumbing problems. A fragile receiver tube can also be employed without rupture difficulties. The thermal processes in the collectors were analyzed using a computer modeling. The results were also used to develop a thermodynamic analysis of the total system. Calculations show that the design is technically feasible. The CPC collector is shown to have an efficiency that is very weakly dependent on its operating temperatures, which makes the collector particularly attractive in high temperature applications.
Date: August 1979
Creator: Argonne National Laboratory. Solar Energy Group.
Partner: UNT Libraries Government Documents Department

Argonne Solar Energy Program Annual Report: 1979

Description: This report describes the R&D work done at Argonne National Laboratory on solar energy technologies during the period October 1, 1978, to September 30, 1979. Technical areas included in the ANL solar program are solar energy collection, heating and cooling, thermal energy storage, ocean thermal energy conversion, photovoltaics, biomass conversion, satellite power systems, and solar liquid-metal MHD power systems.
Date: June 1980
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department

Argonne Solar Energy Program Annual Report: 1979

Description: This report describes the R&D work done at Argonne National Laboratory on solar energy technologies during the period October 1, 1978, to September 30, 1979. Technical areas included in the ANL solar program are solar energy collection, heating and cooling, thermal energy storage, ocean thermal energy conversion, photovoltaics, biomass conversion, satellite power systems, and solar liquid-metal MHD power systems.
Date: June 1980
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department

Copper corrosion and its relationship to solar collectors:a compendium.

Description: Copper has many fine qualities that make it a useful material. It is highly conductive of both heat and electricity, is ductile and workable, and reasonably resistant to corrosion. Because of these advantages, the solar water heating industry has been using it since the mid-1970s as the material of choice for collectors, the fundamental component of a solar water heating system. In most cases copper has performed flawlessly, but in some situations it has been known to fail. Pitting corrosion is the usual failure mode, but erosion can also occur. In 2000 Sandia National Laboratories and the Copper Development Association were asked to analyze the appearance of pin-hole leaks in solar collector units installed in a housing development in Arizona, and in 2002 Sandia analyzed a pitting corrosion event that destroyed a collector system at Camp Pendleton. This report includes copies of the reports and accounts of these corrosion failures, and provides a bibliography with references to many papers and articles that might be of benefit to the solar community. It consolidates in a single source information that has been accumulated at Sandia relative to copper corrosion, especially as it relates to solar water heaters.
Date: July 1, 2007
Creator: Menicucci, David F. & Mahoney, Alan Roderick
Partner: UNT Libraries Government Documents Department

Roof Integrated Solar Absorbers: The Measured Performance of ''Invisible'' Solar Collectors: Preprint

Description: The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory, has investigated the thermal performance of solar absorbers that are an integral, yet indistinguishable, part of a building's roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC's Flexible Roof Facility in Cocoa, Florida, in September 1998. This ''proof-of-concept'' system uses the asphalt shingle roof surface and the plywood decking under the shingles as an unglazed solar absorber. Data was gathered for a one-year period on the system performance. In Phase 2, two more RISA prototypes were constructed and submitted for testing. The first used the asphalt shingles on the roof surface with the tubing mounted on the underside of the plywood decking. The second prototype used metal roofing panels over a plywood substrate and placed the polymer tubing between the plywood decking and the metal roofing. This paper takes a first look at the thermal performance results for the ''invisible'' solar absorbers that use the actual roof surface of a building for solar heat collection.
Date: October 19, 2001
Creator: Colon, C. J. (Florida Solar Energy Center) & Merrigan, T. (National Renewable Energy Laboratory)
Partner: UNT Libraries Government Documents Department

Predicted Heat-Transfer Performance of an Evacuated Glass-Jacketed CPC Receiver : Countercurrent Flow Design

Description: The heat-transfer performance of an evacuated glass-jacketed CPC-receiver facility, free on one end and fixed onto the glass jacket at the other, was carried out using heat-transfer relationships and the best information available in the literature. Specifically, the collector examined was a 3x-CPC facility, 8 ft long, with an entrance aperture 4.5 in. wide covered with a single glass cover, and provided with an aluminum reflecting surface (rho = 0.88). To maximize heat retention, a selectively treated receiver surface, epsilon = 0.11, was used. The optical efficiency of this CPC collector facility was calculated to be eta₀ = 0.536.
Date: May 1976
Creator: Thodos, George
Partner: UNT Libraries Government Documents Department

Analysis of Heat-Pipe Absorbers in Evacuated-Tube Solar Collectors

Description: Heat transfer in evacuated-tube solar collectors with heat-pipe absorbers is compared with that for similar collectors with flow-through absorbers. In systems that produce hot water or other heated fluids, the heat-pipe absorber suffers a heat transfer penalty compared with the flow-through absorber, but in many cases the penalty can be minimized by proper design at the heat-pipe condenser and system manifold. The heat transfer penalty decreases with decreasing collector heat loss coefficient, suggesting that evacuated tubes with optical concentration are more appropriate for use with heat pipes than evacuated or non-evacuated flat-plate collectors. When the solar collector is used to drive an absorption chiller, the heat-pipe absorber has better heat transfer characteristics than the flow-through absorbers.
Date: February 1986
Creator: Hull, John R.; Schertz, William W. & Allen, John W.
Partner: UNT Libraries Government Documents Department

Heat Extraction from the ANL Research Salt Gradient Solar Pond

Description: This report documents the design considerations and test results of two heat extraction systems for the ANL Research Salt Gradient Solar Pond (RSGSP). Since operation began in November 1980, the RSGSP has been used to study a wide variety of solar pond phenomena, and the behavior of the RSGSP without heat extraction has been well characterized. Heat extraction equipment was installed in the spring of 1984, with heat extraction experiments conducted the following summer and fall and in the fall of 1985. The experiments simulated the use of the solar pond for grain drying. The effects of both heat extraction methods on the stability of the salt gradient are investigated.
Date: February 1986
Creator: Hull, John R.; Scranton, A. B.; Mehta, J. M.; Cho, S. H. & Kasza, Kenneth Edmund
Partner: UNT Libraries Government Documents Department

Side-by-Side Comparisons of Evacuated Compound Parabolic Concentrator and Flat Plate Solar Collector Systems

Description: Three liquid-based solar heating systems employing different types of solar collectors were tested side by side near Chicago, Illinois for one year. The three different types of collectors were: (1) a flat plate collector with a black-chrome coated absorber plate and one low-iron glass cover; (2) an evacuated-tube compound parabolic concentrator (CPC) with a concentration ratio of 1.1, oriented with tubes and troughs along a north-south axis; and (3) an evacuated-tube CPC collector with a concentration ratio of 1.3 and one low-iron glass cover, with tubes and troughs oriented along an east-west axis. Results indicate that the flat plate collector system was the most efficient during warm weather, but the CPC systems were more efficient during cold weather, but the CPC systems were more efficient during cold weather, and the CPC systems operated under conditions too adverse for the flat plate collector. The computer simulation model ANSIM was validated by means of the side-by-side tests. The model uses analytical solutions to the storage energy balance. ANSIM is compared with the general simulation TRNSYS.
Date: October 1983
Creator: McGarity, Arthur E.; Allen, John W. & Schertz, William W.
Partner: UNT Libraries Government Documents Department

Atmospheric Corrosion of batten and Enclosure Materials for Flat-Plate Solar Collectors

Description: As part of the Solar Reliability and Materials Program at Argonne National Laboratory, the atmospheric corrosion of candidate batten and enclosure materials were tested on outdoor racks parallel to the tilted solar-collected panels at nine National Solar Data Network (NSDN) sites, located in mild marine, mild industrial, and rural environments. The candidate materials evaluated include galvanized steel (G-90), aluminized steel (Type 2), aluminum (6061), and white polyester painted steel. Data analyses predicted that all the first three materials will last more than 20 years in the nine sites tested. However, repainting of the painted steel is probably needed within five years in a mild marine environment and five to ten years in a mild industrial or rural environment.
Date: April 1983
Creator: Cheng, Craig F.
Partner: UNT Libraries Government Documents Department

Low-cost solar collector test and evaluation. Final report

Description: Project was to test and evaluate a highly efficient low cost solar collector and to make this technology available to the average homeowner. The basic collector design was for use in mass production, so approximately forty collector panels were made for testing and to make it simple to be hand built. The collectors performed better than expected and written and visual material was prepared to make construction easier for a first time builder. Publicity was generated to make public aware of benefits with stories by Associated Press and in publications like Popular Science.
Date: unknown
Creator: Benjamin, C.M.
Partner: UNT Libraries Government Documents Department

Solar collectors for cooling applications

Description: Collector research projects funded by the R and D Branch for Heating and Cooling, Department of Energy, which have direct applicability as cooling machine prime movers, are described. Performance curves are given where they are available along with the development status and the market availability. (MHR)
Date: January 1, 1978
Creator: Collier, R.K.
Partner: UNT Libraries Government Documents Department

Efficiency of a solar collector with internal boiling

Description: The behavior of a solar collector with a boiling fluid is analyzed to provide a simple algebraic model for future systems simulations, and to provide guidance for testing. The efficiency equation is developed in a form linear in the difference between inlet and saturation (boiling) temperatures, whereas the expression upon which ASHRAE Standard 109P is based utilizes the difference between inlet and ambient temperatures. The coefficient of the revised linear term is a week function of collector parameters, weather, and subcooling of the working fluid. For a glazed flat-plate collector with metal absorber, the coefficient is effectively constant. Therefore, testing at multiple values of insolation and subcooling, as specified by ASHRAE 109P, should not be necessary for most collectors. The influences of collector properties and operating conditions on efficiency are examined.
Date: June 1, 1986
Creator: Neeper, D.A.
Partner: UNT Libraries Government Documents Department

Effects of noncontact cleaners on transparent solar materials

Description: A brief study has been undertaken to evaluate the performance of noncontact cleaning agents for use on solar collectors. Several techniques are used to compare cleansing agents which have been recommended by their respective manufacturers for cleaning solar mirrors. Wetting and residue buildup properties are evaluated for over 50 of these commercially available cleaners. The wetting properties of each cleaner are evaluated by measuring the growth of the contact area of a constant volume drop as a function of time. Losses due to residue buildup are solar weighted and considered equally with the wetting parameters and cost figures to construct a figure of merit for cleaner comparison.
Date: April 1, 1979
Creator: Hampton, H.L. & Lind, M.A.
Partner: UNT Libraries Government Documents Department

Low cost, bare plate solar air collector. Semi-annual progress report

Description: A low cost, bare plate solar collector that is specifically designed to preheat ambient air with solar energy is discussed. Two prototype solar collector test systems have been designed, fabricated and assembled. Each system has been instrumented to provide instantaneous and average thermal performance data by means of a computerized data logger system. This data logger system is currently being made operational. Data collection is scheduled to begin March 1, 1980 and continue until the project completion date of June 17, 1980. Some preliminary test data have been obtained for both prototype systems. The results showed that ambient air was preheated between 5/sup 0/F and 10/sup 0/F with the systems achieving a thermal performance of between 15% and 30% efficiency.
Date: January 1, 1980
Partner: UNT Libraries Government Documents Department

Near-term improvements in parabolic troughs: an economic and performance assessment

Description: Improved parabolic-trough concentrating collectors will result from better design, improved fabrication techniques, and the development and utilization of improved materials. This analysis qualifies the performance potential of various parabolic-trough component improvements from a systems viewpoint and uses these performance data to determine the worth of each improvement on an economic basis. The improvements considered are evacuated receivers, silvered-glass reflectors, improved receiver, selective coatings, higher optical accuracy concentrations, and higher transmittance receiver glazings. Upper-bound costs for each improvement are provided as well as estimates of the increased solar system rates of return that are made possible by these improvements. The performance and economic potential of some of these improvements are shown to be substantial, especially at higher collector operating temperatures.
Date: August 1, 1981
Creator: Gee, R. & Murphy, L.M.
Partner: UNT Libraries Government Documents Department

Low cost bare-plate solar air collector

Description: The purpose of this project was to develop a low cost, bare-plate collector, determine its performance for a variety of climatic conditions, analyze the economics of this type of solar collector and evaluate specific applications. Two prototype collectors were designed, fabricated and installed into an instrumented test system. Tests were conducted for a period of five months. Results of the tests showed consistent operating efficiencies of 60% or greater with air preheat temperature uses up to 20/sup 0/F for one of the prototypes. The economic analyses indicated that an installed cost of between $5 and $10 per square foot would make this type of solar system economically viable. For the materials of construction and the type of fabrication and installation perceived, these costs for the bare-plate solar collector are believed to be attainable. Specific applications for preheating ventilation air for schools were evaluated and judged to be economically viable.
Date: September 1, 1980
Creator: Maag, W.L.; Wenzler, C.J.; Rom, F.E. & VanArsdale, D.R.
Partner: UNT Libraries Government Documents Department

Owens-Illinois subsystem design package for the SEC-601 air-cooled solar collector

Description: Information used to evaluate the subsystem design of the Owens-Illinois Model SEC-601 Solar Collector is presented. The collector is of modular design and is approximately 12 feet 3 inches wide and 8 feet 7 inches tall. It contains 72 collector tube elements and weighs approximately 300 pounds. Included in this report are the Subsystem Performance Specifications and the Assembly and Installation Drawings of the Solar Collectors and Manifold.
Date: February 1, 1979
Partner: UNT Libraries Government Documents Department