Experimental Study on a Solar Heat Concentrating Steam Generator
Replacing of complex solar concentrating unit, this paper designs a solar heat-concentrating medium-temperature steam-generating system. Solar radiation is collected by using a large solar collecting and heat concentrating plate and is converged to the metal evaporating pipe with high efficient heat transfer. In the meantime, the heat loss is reduced by employing a double-glazed cover and other heat insulating structures. Thus, a high temperature is reached in the metal evaporating pipe. The influences of the system's structure parameters on system performance are analyzed. The steam production rate and the steam production under different solar irradiance, solar collecting and heat concentrating plate area, solar collecting and heat concentrating plate temperature and heat loss are obtained. The results show that when solar irradiance is higher than 600 W/m2, the effective heat collecting area is 7.6 m2 and the double-glazing cover is adopted, the system heat loss amount is lower than the solar irradiance value. The stable steam is produced in the metal evaporating pipe at 100 ℃, 110 ℃, and 120 ℃, respectively. When the average solar irradiance is about 896 W/m2, and the steaming cumulative time is about 5 hours, the daily steam production of the system is about 6.174 kg. In a single day, the solar irradiance is larger at noon, thus the steam production rate is large at that time. Before 9:00 and after 16:00, the solar irradiance is smaller, and the steam production rate is almost 0.
 Mekhilef S, Saidur R, Safari A. A review on solar energy use in industries. Renew Sustain Energy Rev 2011;15:1777-1790.
 Kalogirou S. The potential of solar industrial process heat applications. Appl Energy2003;76:337-361.
 Zhang L, Yu Z, Fan L, Wang W, Chen H, Hu Y, et al. An experimental investigation of the heat losses of a U-type solar heat pipe receiver of a parabolic trough collector-based natural circulation steam generation system. Renew Energy2013; 57:262-268.
 Zhang L, Wang W, Yu Z, Fan L, Hu Y, Ni Y, et al. An experimental investigation of a natural circulation heat pipe system applied to a parabolic trough solar collector steam generation system. Sol Energy 2012;86:911-919.
 Zhang L, Fan L, Hua M, Zhu Z, Wu Y, Yu Z, et al. An indoor experimental investigation of the thermal performance of a TPLT-based natural circulation steam generator as applied to PTC systems. Appl Therm Eng2014; 62:330-340.
 Thomas A. Solar steam generating systems using parabolic trough concentrators. Energy Convers Manag 1996; 37:215-245.
 Kalogirou S, Lloyd S, Ward J. Modelling, optimisation and performance evaluation of a parabolic trough solar collector steam generation system. Sol. Energy1997; 60:49-59.
 Zarza E, Valenzuela L, Leo'n J, Hennecke K, Eck M, Weyers H, et al. Direct steam generation in parabolic troughs: final results and conclusions of the DISS project. Energy2004;29:635-644.
 Pollerberg C, Ali A H H, Dötsch C. Solar driven steam jet ejector chiller. Appl Therm Eng 2009;29:1245-1252.
 Riffat S, Mayere A. Performance evaluation of v-trough solar concentrator for water desalination applications. Appl Therm Eng 2013;50:234-244.
 Ling D L, Li M, Luo X, Ji X, Liu J T, Zhang P, et al. Study on drying characteristics of cut tobacco based on trough concentrating solar heating. Acta Energiae Solaris Sinica 2015;2:460-466.
 Tan L J, Ji X, Li M, Leng C B, Luo X, Li H L, The experimental study of a two-stage photovoltaic thermal system based on solar trough concentration. Energy Convers Manage 2014;86: 410-417.
 Ji X, Tan L J, Li M, Tang R S, Wang Y F, Song X B, et al. Improvement of Energy Comprehensive Utilization in a Solar Trough Concentrating PV/T System. J Energ Eng2016;142:UNSP 04016013.
 Liu Z H, Tao G D, Lu L, Wang Q. A novel all-glass evacuated tubular solar steam generator with simplified CPC. Energy Convers Manage 2014;86:175-185.
 Oommena R, Jayaramanb S. Development and performance analysis of compound parabolic solar concentrators with reduced gap losses-oversized reflector. Energy Convers Manage 2001;11:1379-1399.
 Cai D. Prototype design and experiment based on solar CPC concentrated drying technology for printing and dyeing sludge drying. Zhejiang University of Technology; 2014.
 Li X, Dai Y J, Li Y, Wang R Z. Comparative study on two novel intermediate temperature CPC solar collectors with the U-shape evacuated tubular absorber. Sol Energy2013;93:220-234.
 Buker M S, Riffat S B. Building integrated solar thermal collectors–A review. Renew Sustain Energy Rev2015;51:327-346.
 Nagarajana P K, Subramania J, Suyambazhahana S, Sathyamurthyb R. Nanofluids for Solar Collector Applications: A Review. Energy Pro2014;61:2416-2434.
 Zhang C Z, Xu G Q, Quan Y K, Li H W, Song G. Optical sensitivity analysis of geometrical deformation on the parabolic trough solar collector with Monte Carlo Ray-Trace method. Appl Therm EngPart A; 2016;109:130-137.
 Pandey K M, Chaurasiya R. A review on analysis and development of solar flat plate collector. Renew Sustain Energy Rev2017;67:641-650.
 Edalatpoura M, Solanob J P. Thermal-hydraulic characteristics and exergy performance in tube-on-sheet flat plate solar collectors: Effects of nanofluids and mixed convection. Int JTherm Sci 2017;118:397-409.
 Zhang J D, Tao H Z, Chen S S. Numerical simulation for structural parameters of flat-plate solar collector. Sol Energy2015;117:192-202.
 Ni G, Li G, Boriskina S V, Li H X, Yang W L, Zhang T J, et al. Steam generation under one sun enabled by a floating structure with thermal concentration. Nat Energy, 2016;1:16126.
 Hadi Ghasemi, George Ni, Amy Marie Marconnet, James Loomis, Selcuk Yerci, Nenad Miljkovic, Gang Chen, Solar steam generation by heat localization, Nature Communications, 2014, 5,4449.
 Zhou L, Tan Y L, Wang J Y, Xu W C, Yuan Y, Cai W S, et al. 3Dself-assembly of aluminium nanoparticles for plasmon-enhanced solar desalination. Nat Photonics 2016;10:393-398.
 Li X Q, Xu W C, Tang M Y, Zhou L, Zhu B, Zhu S N, et al. Graphene oxide-based efficient and scalable solar desalination under one sun with a confined 2D water path. PNAS 2016;113: 13953-13958.
 Zhou L, Zhuang S D, He C Y, Tan Y L, Wang Z L, Zhu J. Self-assembled spectrum selective plasmonic absorbers with tunable bandwidth for solar energy conversion. Nano Energy 2017;32:195-200.
 Neumann O, Feronti C, Neumann A D, Dong A, Schell K, Lu B, et al. Halas Compact solar autoclave based on steam generation using broadband light-harvesting nanoparticles. Proc Natl Acad Sci USA 2013;110:1677-11681.
 Ni George, Miljkovic N, Ghasemi H, Huang X, Boriskina S V, Lin C T, et al. Volumetric solar heating of nanofluids for direct vapor generation. Nano Energy, 2015;17:290-301.
 Muhammad Amjad, Ghulam Raza, Yan Xin, Shahid Pervaiz, Jinliang Xu, Xiaoze Du, Dongsheng Wen. Volumetric solar heating and steam generation via gold nanofluids, Applied Energy, 2017, 206: 393-400.