Detailed Performance Analysis of a 10kW Dish∕Stirling System

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
W. Reinalter ◽  
S. Ulmer ◽  
P. Heller ◽  
T. Rauch ◽  
J.-M. Gineste ◽  
...  

The CNRS-Promes dish∕Stirling system was erected in Jun. 2004 as the last of three country reference units built in the “Envirodish” project. It represents the latest development step of the EuroDish system with many improved components. With a measured peak of 11kW electrical output power, it is also the best performing system so far. The measurement campaign to determine the optical and thermodynamic efficiency of the system is presented. The optical quality of the concentrator and the energy input to the power conversion unit was measured with a classical flux-mapping system using a Lambertian target and a charge coupled device camera system. An efficiency of the concentrator including the intercept losses of 74.4% could be defined for this particular system. For the thermodynamic analysis all the data necessary for a complete energy balance around the Stirling engine were measured or approximated by calculations. For the given ambient conditions during the tests, a Stirling engine efficiency of 39.4% could be measured. The overall efficiency for the conversion of solar to electric energy was 22.5%.

1997 ◽  
Vol 68 (7) ◽  
pp. 2698-2706
Author(s):  
M. Sarstedt ◽  
R. Dölling ◽  
L. Wicke ◽  
H. Klein

Author(s):  
J. Gordon Robertson

Abstract One of the basic parameters of a charge coupled device (CCD) camera is its gain, that is, the number of detected electrons per output Analogue to Digital Unit (ADU). This is normally determined by finding the statistical variances from a series of flat-field exposures with nearly constant levels over substantial areas, and making use of the fact that photon (Poisson) noise has variance equal to the mean. However, when a CCD has been installed in a spectroscopic instrument fed by numerous optical fibres, or with an echelle format, it is no longer possible to obtain illumination that is constant over large areas. Instead of making do with selected small areas, it is shown here that the wide variation of signal level in a spectroscopic ‘flat-field’ can be used to obtain accurate values of the CCD gain, needing only a matched pair of exposures (that differ in their realisation of the noise). Once the gain is known, the CCD readout noise (in electrons) is easily found from a pair of bias frames. Spatial stability of the image in the two flat-fields is important, although correction of minor shifts is shown to be possible, at the expense of further analysis.


2009 ◽  
Vol 101 (2) ◽  
pp. 591-602 ◽  
Author(s):  
Hiraku Mochida ◽  
Gilles Fortin ◽  
Jean Champagnat ◽  
Joel C. Glover

To better characterize the emergence of spontaneous neuronal activity in the developing hindbrain, spontaneous activity was recorded optically from defined projection neuron populations in isolated preparations of the brain stem of the chicken embryo. Ipsilaterally projecting reticulospinal (RS) neurons and several groups of vestibuloocular (VO) neurons were labeled retrogradely with Calcium Green-1 dextran amine and spontaneous calcium transients were recorded using a charge-coupled-device camera mounted on a fluorescence microscope. Simultaneous extracellular recordings were made from one of the trigeminal motor nerves (nV) to register the occurrence of spontaneous synchronous bursts of activity. Two types of spontaneous activity were observed: synchronous events (SEs), which occurred in register with spontaneous bursts in nV once every few minutes and were tetrodotoxin (TTX) dependent, and asynchronous events (AEs), which occurred in the intervals between SEs and were TTX resistant. AEs occurred developmentally before SEs and were in general smaller and more variable in amplitude than SEs. SEs appeared at the same stage as nV bursts early on embryonic day 4, first in RS neurons and then in VO neurons. All RS neurons participated equally in SEs from the outset, whereas different subpopulations of VO neurons participated differentially, both in terms of the proportion of neurons that exhibited SEs, the fidelity with which the SEs in individual neurons followed the nV bursts, and the developmental stage at which SEs appeared and matured. The results show that spontaneous activity is expressed heterogeneously among hindbrain projection neuron populations, suggesting its differential involvement in the formation of different functional neuronal circuits.


2016 ◽  
Vol 9 (2) ◽  
pp. 423-440 ◽  
Author(s):  
K.-E. Min ◽  
R. A. Washenfelder ◽  
W. P. Dubé ◽  
A. O. Langford ◽  
P. M. Edwards ◽  
...  

Abstract. We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361–389 and 438–468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.


1995 ◽  
Vol 9 (3) ◽  
pp. 477-483 ◽  
Author(s):  
Hubert W. Carson ◽  
Lawrence W. Lass ◽  
Robert H. Callihan

Yellow hawkweed infests permanent upland pastures and forest meadows in northern Idaho. Conventional surveys to determine infestations of this weed are not practical. A charge coupled device with spectral filters mounted in an airplane was used to obtain digital images (1 m resolution) of flowering yellow hawkweed. Supervised classification of the digital images predicted more area infested by yellow hawkweed than did unsupervised classification. Where yellow hawkweed was the dominant ground cover species, infestations were detectable with high accuracy from digital images. Moderate yellow hawkweed infestation detection was unreliable, and areas having less than 20% yellow hawkweed cover were not detected.


2004 ◽  
Vol 43 (1) ◽  
pp. 33 ◽  
Author(s):  
Alexander G. Simpson ◽  
Kaiming Zhou ◽  
Lin Zhang ◽  
Lorna Everall ◽  
Ian Bennion

2009 ◽  
Vol 47 (7) ◽  
pp. 454-455 ◽  
Author(s):  
Michael F. Santillo

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