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Comparative Assessment on the Use of Energy Storage in the Building Envelopes
Published in Atul Sharma, Amritanshu Shukla, Renu Singh, Low Carbon Energy Supply Technologies and Systems, 2020
Maitiniyazi Bake, Ashish Shukla, Shuli Liu, Avlokita Agrawal, Shiva Gorijan
PCM storage is likely to become a viable technology in the next few years. For instance, it can be concluded that PCM-based thermal storage in conjunction with an electric air-source heat pump, offered as part of a Green Deal, could be technically possible in retrofit buildings. Also, the introduction of a thermal store as part of a heating system offers a potential economic impact, through the requirements for initial installation and ongoing maintenance. Moreover, the use of latent heat energy storage is finding applications in the built environment with PCMs used in building cooling systems to displace peak cooling loads and by using microencapsulated PCMs in the building fabric. This paper also displays some case studies on the performance of PCMs in building envelope as follows.
D/A and A/D Converters
Published in Jerry C. Whitaker, Microelectronics, 2018
PCM is a technique where an analog signal is sampled, quantized, and then encoded as a digital word. The PCM IC can include successive approximation techniques or other techniques to accomplish the PCM encoding. In addition, the PCM codec may employ nonlinear data compression techniques, such as companding, if it is necessary to minimize the number of bits in the output digital code. Companding is a logarithmic technique used to compress a code to fewer bits before transmission. The inverse logarithmic function is then used to expand the code to its original number of bits before converting it to the analog signal. Companding is typically used in telecommunications transmission systems to minimize data transmission rates without degrading the resolution of low-amplitude signals. Two standardized companding techniques are used extensively: A-law and μ-law. The A-law companding is used in Europe, whereas the μ-law is used predominantly in the United States and Japan. Linear PCM conversion is used in high-fidelity audio systems to preserve the integrity of the audio signal throughout the entire analog range.
D/A and A/D Converters
Published in Jerry D. Gibson, The Communications Handbook, 2018
PCM is a technique whereby an analog signal is sampled, quantized, and then encoded as a digital word. The PCM IC can include successive approximation techniques or other techniques to accomplish the PCM encoding. In addition, the PCM codec may employ nonlinear data compression techniques, such as companding, if it is necessary to minimize the number of bits in the output digital code. Companding is a logarithmic technique used to compress a code to fewer bits before transmission. The inverse
Estimation of time-dependent neutron transport from point source based on Monte Carlo power iteration
Published in Journal of Nuclear Science and Technology, 2019
For flux calculation by time T, calculation must be continued until cycle N, where the all source neutrons are emitted after T. That can be monitored by the neutron flux tallied over all fuel elements at the time bin including T, whether it increases between cycles N – 1 and N, because all neutron tracks in a cycle start in the fuel elements. For the flux estimation where the delayed neutrons take a significant role, it is necessary to continue the PI calculations so that delayed neutrons are sampled many times in the family lines of neutrons. The sampling ratio of the precursors of the first group is only 22 pcm in the calculations described in Section 4. Therefore, the PI calculations should be done more than 20,000 cycles to sample the first group four or five times, on average, in a family line.
Dynamic Modeling and Performance Analysis of a Two-Fluid Molten-Salt Breeder Reactor System
Published in Nuclear Technology, 2018
Vikram Singh, Matthew R. Lish, Alexander M. Wheeler, Ondřej Chvála, Belle R. Upadhyaya
Bode plots are beneficial in assessing the stability of a plant for a wide range of input frequencies. The conventional method is to linearize the plant model and determine appropriate transfer functions (TFs). A nonlinear system such as the one presented here should, however, behave linearly for small deviations from steady state. Within the range of linear behavior, the plant response frequency is equal to the input frequency. Thus, the MSBR power-to-reactivity frequency response is found using a sinusoidal reactivity insertion of amplitude ~1 pcm. The resulting power response is measured and the change in magnitude and phase recorded for a range of input frequencies. Figure 14 shows the frequency response of the MSBR plant at thermal power levels of 556, 256, and 56 MW and zero-power (~1 kW) to external reactivity perturbations. In each case, 94.75% of the heat generated in the core is carried away by the fuel salt and 5.25% by the fertile-salt stream. For this simulation, the primary loop flow rates are not changed for high power levels. In the zero-power case, the absence of control action means the reactor is approximated as a static fuel reactor and an appropriate TF is derived. In all cases, the frequency response results are indicative of a well-behaved system.
Uncertainty analysis of the OECD/NEA LWR UAM benchmark Phase I using CASMO5 with JENDL-4.0 and ENDF/B-VII.1
Published in Journal of Nuclear Science and Technology, 2020
Tatsuya Fujita, Tomohiro Sakai
As a preliminary analysis prior to the uncertainty analysis, a number of sampling calculations, which was sufficient to converge the statistic, were discussed. By performing 10,000 sampling calculations, it was confirmed that the statistic of the k-infinity satisfied the convergence within 10 pcm in more than 4000 times of sampling calculations. Thus, the number of sampling calculations was determined as 4000.