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A novel multiple curved surfaces compound concentrator is developed in this paper. It is composed of a parabolic and a flat contour. This new concentrator has a focus at the backside which is extremely useful and convenient for some applications. The reflected rays here are transmitted forward instead of backward as in the conventional parabolic concentrators. The design method of the concentrator is introduced. Some of important parameters are discussed and the value rang of them is determined. Simple comparisons between proposed concentrators and traditional paraboloid and CPC are made. Light rays tracing are carried out in the concentrator.

The operation principle and design method of a new trough solar concentrator is presented in this paper. Some important design parameters about the concentrator are analyzed and optimized. Their magnitude ranges are given. Some characteristic parameters about the concentrator are compared with that of the conventional parabolic trough solar concentrator. The factors having influence on the performance of the unit are discussed. It is indicated through the analysis that the new trough solar concentrator can actualize reflection focusing for the sun light using multiple curved surface compound method. It also has the advantages of improving the work performance and environment of high-temperature solar absorber and enhancing the configuration intensity of the reflection surface.

A solar stove which uses a light funnel to guide light and congregate solar energy has been designed. Its structure and operation principle have been introduced. The performance tests under the real weather have been carried out and the graphic lines of experiment have been given. The experimental result shows that the maximum temperature inside the stove is as high as 250 °C under the condition of 1.5 m 2 of lighting area, 70% reflectivity of reflecting aluminum foil inside surface of concentrator and no load (without water inside the coil pipe). When reflectivity is 86% the heat collecting efficiency of the device is about 43%. The collecting power that the stove receives can be up to 500 W. It is an ideal medium and high temperature solar energy congregating device suitable for industrial usage or cooking and other domestic usage.

Three types of congregated solar concentrators or so-called light funnels have been designed. They are a Compound Parabolic Concentrators (CPC) superposed light funnel, a CPC superposed light funnel with a deflector and a mirror focus superposition light funnel. Their light-concentrating principle and light conduction process have been analyzed. Their performances have been discussed after testing under real weather conditions, and also their conducting light rates and curve of conducting light performance for different incident angles have been calculated. The experimental results show that the conducting light rate of the mirror focus superposition-type light funnel is maximum, up to 35.1%. The CPC superposed light funnel has a minimum value, with only 25.6%. The CPC superposed light funnel is the most demanding regarding tracking accuracy. The other two types of concentrators are less demanding concerning tracking accuracy. Copyright The Author 2009. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org, Oxford University Press.

Based on the mechanism of falling film evaporation and condensation, a quadruple effect regeneration absorption solar desalination unit was designed and tested indoors under transient and steady-state conditions. The performance ratio and the flow rate of freshwater of the unit at different operating temperature and pressure were studied. Through the test, it is shown that the performance ratio of the unit is high because most of latent heat of vapors and part of sensible heat of brine are utilized many times. Meantime, lithium bromide can automatically absorb the vapors of the last stage evaporator so as to recover vapor enthalpy and intensify the process of evaporation. The PR of the unit is more than 3.0, which illustrates the advantages of the absorption desalination system. The other factors influencing the flow rate of freshwater were also researched. From the indoor experimental results, the solar heating system of the unit was studied by simulation under the conditions of the least cost of fresh w...

A special desalinization unit which utilizes solar or waste energy has been developed and tested indoors. In thisunit, a relatively large fraction of latent and sensible heat of condensation along with brine is successfully recycled and utilized. It is used to preheat and evaporate the feedstock due to the multi-effect thermal regenerative process. Since the falling film evaporation is used and the system posses the characteristics of flash distillation and vapor compression, the thermal performance of the system is improved greatly. As a result of the simulation of the unitoperating with a solar system under practical weather conditions, the yield is about two times greater than that of a conventional single basin solar still with the same thermal energy input. The transient-state performance of the unit, the relationships among the operating temperature, feedstock flow rate and the productivity are presented. Other factors which influence the freshwater yield are also discussed.

After the analysis of the multi-stage tower type of solar desalination unit[1], the unit is optimized and theoretically studied. Through combing the optimized unit with a solar heating system and the simulation with a sort of solar collector by utilizing the hourly irradiance and daily mean ambient temperature, the influences of the parameters of the unit on the production cost of freshwater are discussed. Also the variation curves and the optimal values of these parameters are given.

An imaging CPC is developed. This new concentrator has three remarkable characteristics: First, focus of the concentrator is located outside the concave of the compound parabolic concentrator while the focus of the paraboloid is located inside. This characteristic is in favor of the installation and maintenance of the energy receiver. It is also beneficial to the disposal of the heat preservation for the received solar energy. Secondly, when it is combined to the conventional paraboloid it can changes a big beam of parallel light into a small beam of parallel light with bigger density of energy. Thus, the multiplication of energy flow density can be realized. Finally, the direction of its emerging rays can be adjusted in a very big solid angle (bigger than 2?).This characteristic is very favor of the utilization of the conducting light technology such as for the synchro indoor or underground illumination in the daytime.

Based on the characteristics of falling film evaporation and condensation processes having high heat transfer coefficient, an absorption solar desalination unit combined with a low-temperature multi-effect parts was designed. The variation curves of the yield of the unit with its operating temperature were given through the indoor steady state experiment. According to the experimental results, the energy and exergy efficiencies of unit are discussed and the heat and mass transfer processes between the parts of the unit are analyzed. The improving and optimizing suggestions of the unit are given after comparing calculation results.

A solar boiled water device has been designed and the correlative experiments have been carried out. The device mainly consists of two parts. The first part adopts the technology of vacuum tube solar collecting heat and can produces hot water at a certain temperature. The second part adopts the technology of light guide assembling energy and heat storage. It further heats the hot water and makes it boil. After the second part there is a temperature-control electromagnetic valve that switches on while water boiling. The device can provide boiled water in a short time after the system start up. With the technology of the heat storage, the effect of the fluctuation of the sun light on the device is weakened largely. The graph of the output of the boiled water with the operation time has been given. The COP of the device is about 0.5.