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UL 62108-2017 pdf free download
UL 62108-2017 pdf free download.Concentrator Photovoltaic (CPV) Modules and Assemblies — Design Qualification and Type Approval.
(instead of using the chamber temperature to cycle the temperature). The current shall then be cycled to duplicate the standard test profile listed in Table 3. The system can be run dry with no cooling fluid present during the duration of this test. The current injection will raise the cell(s) temperature(s) to one of the values in Table 3 (see Note).
The heat-sink temperature shall be monitored at a location as close to the cell as possible during temperature cycling — and the chamber temperature adjusted to ensure that this heat-sink temperature does not exceed the test chamber temperature. The exact location of the heat sink temperature measurement location shall be noted on the measurement report.
When the sample has parallel strings, make sure that the required current is supplied to each single string. Sometimes this will require separating the parallel strings, and to use separate power supplies for each string.
Based on the knowledge as this standard is written, some large-area Ill-V cells may not be able to hold up under option a) or C), and some testing facilities may have an equipment limitation to perform option b). In these cases, the thermal cycle test sequence A could be conducted without applying the current, but the manufacturer should prepare three additional receiver samples with similar, but dead, cells, i.e., electrically inactive Ill-V cells. A minimum of 1,25 I should be provided in either positive or negative direction. The current should be controlled to maintain a temperature difference between the cell and heat sink comparable to, or greater than, operating conditions so that the localized heating can take place, and the ability of the receivers to withstand thermal mismatch, fatigue, and other stresses can be evaluated. The thermal gradients during operating conditions can be determined from commercially available modeling programs or from direct measurements when DNI is greater than 700 W/m2 and wind speed is less than 2 rn/s. The pass criteria for these receiver samples will be changed to: after the thermal cycle test, the change of the receiver resistance shall be less than 2 % (excluding the cell). This alternative procedure will be re-evaluated, and if necessary, an amendment to this standard will be issued, as soon as further knowledge on this topic becomes available.
NOTE Actively cooled systems are typically designed to handle a very large heat load, II coolant is pesant. it may not be possible to heat the system to the target temperatures, but it the cootant is removed and (1.) bias current is applied, the temperature can reach art)tranly high temperatures. Thermal cycling because of bias current applies stress differently than thermal cycling the chamber and may be especially effective if a senes resistance develops that enhances local heating from the flow of current.
There will be one current cycle for each temperature cycle. Current flow shall commence during the upward temperature ramp when the heat-sink temperature reaches 25 9C and stop at the end of the maximum temperature dwell (see illustration in Figure 8). The sample’s circuit continuity shall be monitored and recorded.UL 62108-2017 pdf free download.
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