Modeling and Sizing of a MW Solar DSG plant

Direct Steam Generation (DSG) Concentrated Solar technology, based on Linear Fresnel Reflectors (LFR) and aimed at supplying saturated steam to industrial processes, is a promising application; nevertheless, nowadays few case studies and very few installations have been developed. A methodology for the design optimization of a MW solar DSG plant is presented in this article and applied to a real case study of a Brazilian tire manufacturing facility. A steady-state model, with spatial discretization of the ordinary equations, allows characterizing the physical phenomena such as pressure drop and heat transfer, and therefore to determine the pressure and specific enthalpy trend along the recirculation loop. For each receiver tube of the solar collectors, the occurring single or two-phase flow pattern is calculated based on specific empirical equations developed for evaporation in horizontal tubes. Two reference operating conditions have been identified for the present case study, at which the optimal field layout results to be a series connection of all the collectors, and the optimal nominal flow rate to avoid possible harmful operating conditions for the absorber tubes is 1.0 kg/s. © 2016 The Authors

SHC Task 48 B2 – Three GOOD Practice Examples of Solar Heat Driven Desiccant Evaporative Cooling Systems☆

Abstract Within the activity B2 of IEA SHC Task48, an exhaustive report on GOOD Practice examples of existing solar heat driven desiccant cooling (SDEC) systems was written. Three SDEC systems from Austria, Australia and Italy are well documented from the design phase to the operational phase. The authors of the GOOD Practice SDEC systems belong to research entities and the selected SDEC projects were scientifically accompanied by these partners from the very beginning on. The energy performance of all three SDEC systems in operation is indicated by monthly energy fluxes and key performance indicator as a result from measurement data of a scientific monitoring campaign. The GOOD Practice SDEC report on each system closes with findings and lessons learned in order to guide next projects by answering; What quality and support measures lead to a successful SDEC system implementation with high energy performance figures, high quality of indoor comfort and high user friendliness for facility manager? The SHC Task48 B2 report is published on the official SHC Task48 website

Solar Thermal Plant Integration into an Industrial Process

AbstractThe present abstract summarizes the main analysis and design steps made for the integration of a solar thermal plant of one thousand square meters into the dyeing process of Benetton industrial facility in Tunisia. The analysis of the actual process load is done by a static model based on assumed energy and water consumptions and the real performance of the heat recovery system. The methodology to build the simplified model and its validation by monitored data will be presented. The results show the optimization potential of the heat recovery system and the temperature constraints for a good integration of the solar plant.This study presents some choices to reach an optimized integration of the solar plant and the sizing of the main components. The main design alternatives are evaluated in this article based on dynamic simulations and personal experience

A Continuous Commissioning Analysis and its Application to a New Installed Solar Driven DEC System Coupled with Heat Pump

AbstractThe aim of this paper is to define and implement a continuous commissioning methodology that can be effectively applied to a solar driven desiccant and evaporative cooling (DEC) system. The objective is to assess the energy performance of the system's components and identify possible operation faults. The methodology consists in the breakdown and analysis of the DEC into sub-systems; for each of them a simplified dynamic mathematical model based on experimental data has been developed. A possible fault is detected when the difference between the theoretical and measured performances is higher than the accuracy of the methodology. The proposed methodology has been successfully implemented for a hybrid solar DEC system comprising a non-conventional DEC air-handling unit, a solar thermal system and an electrical heat pump.The results of the methodology's application to the first experimental data of summer 2014lead to the following conclusions: the solar sub-system operated as expected whereas the heat pump and the desiccant rotor did not. In particular, the electrical heat pump has a higher cooling capacity than the one predicted at partial load but with a similar COP value, this deviation is mainly due to the assumed partial load performance coefficient. The desiccant rotor presents a much lower performance than the one expected. However, the rotor inefficiency is difficult to highlight due to the high measurement uncertainties on the air side

Beat note stabilization of a 10-60 GHz dual-polarization Nd:YAG microchip laser through optical down conversion

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Non-linear optoelectronic phase-locked loop for stabilization of opto-millimeter waves: towards a narrow linewidth tunable THz source.

International audienceWe propose an optoelectronic phase-locked loop concept which enables to stabilize optical beat notes at high frequencies in the mm-wave domain. It relies on the use of a nonlinear-response Mach-Zehnder modulator. This concept is demonstrated at 100 GHz using a two-axis dual-frequency laser turned into a voltage controlled oscillator by means of an intracavity electrooptic crystal. A relative frequency stability better than 10⁻¹¹ is reported. This approach of optoelectronic down conversion opens the way to the realization of continuously tunable ultra-narrow linewidth THz radiation

40-GHz Photonic Synthesizer Using a Dual-Polarization Microlaser

International audienceAn optically carried microwave synthesis working at 40 GHz is demonstrated by using a two-frequency solid-state microchip laser inserted as a voltage-controlled oscillator inside a digital phase-locked loop. We report an in-loop relative frequency stability better than 2.5 × 10-11. The capabilities of the synthesis are illustrated with different frequency sweeping formats

Optoelectronic phase-locked loop for millimeter-wave and THz beat note stabilization

International audienceA novel scheme based on opto-electronic down conversion is proposed and demonstrated to obtain an ultra-high spectral purity and tunable optical beat note in the GHz and millimeter wave range. An in-loop relative frequency stability better than 4 10-12 is reported. This approach opens the way to THz metrology

Opto-electronic Down Conversion: A Novel Approach for Optical Beat Note Stabilisation Up to the THz Domain

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