Validation of CFD simulation for flat plate solar energy collector

The problem of flat plate solar energy collector with water flow is simulated and analyzed using computational fluid dynamics (CFD) software. The considered case includes the CFD modeling of solar irradiation and the modes of mixed convection and radiation heat transfer between tube surface, glass cover, side walls, and insulating base of the collector as well as the mixed convective heat transfer in the circulating water inside the tube and conduction between the base and tube material. The collector performance, after obtaining 3-D temperature distribution over the volume of the body of the collector, was studied with and without circulating water flow. An experimental model was built and experiments were performed to validate the CFD model. The outlet temperature of water is compared with experimental results and there is a good agreement.     

Experimental study on house cooling and heating with solar energy using flat plate collector

The OSE Project aims at developing the technology to utilize solar energy for heating, cooling and hot water supply on the basis of various technology for energy conservation in buildings. For the first step of this project a solar heating and cooling system with flat plate collectors and absorption refrigeration machine was installed in a house in 1974. This paper reports outlines of the system and operating results.     

板式太阳能集热器装置

提出一款符合发展潮流的实用型板式太阳能集热器装置。     

Performance investigation on a thermal energy storage integrated solar collector system using nanofluid

The effect of Fe nanofluid on the performance enhancement on solar water heater integrated with thermal energy storage system is investigated experimentally. A 0.5% wt fraction of Fe nanoparticle was synthesized with the mixture of water/propylene‐glycol base fluid. The experimental implementation utilized 40‐nm‐size Fe nanoparticle, 15 ° collector tilt angle, and 1.5 kg/min mass flow rate heat‐transfer fluid circulation. The system efficiency reached 59.5% and 50.5% for with and without nanofluid. The water tank temperature was increased by 13 °C during night mode. The average water tank temperature at night mode was 47.5 °C, while the average ambient temperature was 26 °C. The Fe nanofluid improved the system working duration during night mode by an average of 5 h. The techno‐economic analysis results showed a yearly estimated cost savings of 28.5% using the Fe nanofluids as heat transfer fluid. The embodied energy emission rate, collector size, and weight can be reduced by 9.5% using nanofluids. Copyright © 2016 John Wiley & Sons, Ltd.     

Exergetic optimization of solar collector and thermal energy storage system

This paper deals with the exergetic optimization of a solar thermal energy system. This consists of a solar collector (SC) and a rectangular water storage tank (ST) that contains a phase change material (PCM) distributed in an assembly of slabs. The study takes into account both conduction and convection heat transfer mode for water in the SC, and also the phase change process for the PCM in the ST. An analytical solution for the melting process in the PCM is also presented. The results of the study are compared with previous experimental data, confirming the accuracy of the model. Results of a numerical case study are presented and discussed.     

Analysis of a flat plate solar collector/storage water heater with evaporation

We analyse the performance of a flat-plate collector with a constant rate of evaporation of flowing water between a glass cover and an absorbing plate. The effects of fluid-flow velocity, depth of fluid and length of the absorbing surface are discussed. We have allowed for periodic variation of the solar intensity and ambient air temperature during a typical day in New Delhi.     

Comparative study based on exergy analysis of solar air heater collector using thermal energy storage

This communication presents the comparative experimental study based on energy and exergy analyses of a typical solar air heater collector with and without temporary heat energy storage (THES) material, viz. paraffin wax and hytherm oil. Based on the experimental observations, the first law and the second law efficiencies have been calculated with respect to the available solar radiation for three different arrangements, viz. one arrangement without heat storage material and two arrangements with THES, viz. hytherm oil and paraffin wax, respectively. It is found that both the efficiencies in case of heat storage material/fluid are significantly higher than that of without THES, besides both the efficiencies in case of paraffin wax are slightly higher than that of hytherm oil case. Copyright © 2011 John Wiley & Sons, Ltd.     

Enhanced solar energy collection using reflector-solar thermal collector combinations

The amount of direct light gathered by a combination of reflector plus flat-plate collector has been analyzed. The calculations were done allowing variable reflector and collector orientation angles, variables latitude, and arbitrary sun hour angle away from solar noon. The effects of reflection and transmission losses and of polarization of the incident light were included. Correction was also made for the finite size of the reflector. It was found that the optimum orientation has the collector plane almost perpendicular to the plane of the reflector. This optimum orientation is approximately independent of the sun's azimuthal dependence. The optimum reflector angle is found to be between 0° and 10° above the horizon for winter solar conditions. For typical winter operating conditions the enhancement in light gathering power for direct solar radiation is about a factor of 1·4–1·7. This results in an effective increase of 100% in the useful winter heat output from a practical reflector-collector combination with a reflector angle of 0°, over the useful heat output obtained with an optimally oriented simple flat-plate collector. An approximate calculation was also made of the overall enhancement in useful heat output for diffuse solar radiation; an increase by a factor of about 1·5 is predicted. Comparison with the preliminary analysis of the performance of the Coos Bay, Oregon solar house shows substantial agreement with the predictions of the present analysis.     

Dual functioning flat plate thermal solar collector

The purpose of this paper is to investigate the cost effectiveness of a self-constructed and installed flat plate solar energy collector. The report analyzes the theoretical energy output of the solar collector, the experimental measured energy output and the theoretical insulation properties of the collector as constructed and installed.The results obtained indicate the collector is cost effective because of its insulation property when installed inside a single glazed window. The collector produces a relatively small energy income as a solar energy collector.     

Central collector solar energy receivers

Central receivers for use with power-generating equipment require compact boiler and superheater designs to effectively concentrate the solar heat input and to improve system power cycle efficiency. Solar thermal collectors employ a central receiver that must be compact to effectively utilize the high concentration ratios of sunlight energy. The demonstration of lightweight, long-life receiver designs is a technology issue that must be resolved if the concept is to be attractive for power generation. The receiver must be lightweight to minimize the cost of the supporting tower structure. Current applied aerospace technology in compact steam boilers and rocket thrust chamber designs can be directly applied to the design and fabrication of solar central receivers.This technology recently has been applied to a compact steam generator that uses liquid oxygen and natural gas, propane or fuel oil. The compact steam generator permits a 300:1 size reduction in boiler and superheater size. This paper discusses the application of the compact steam generator technology to the design and fabrication of central receivers for solar-energy-powered electrical powerplants. Receiver designs are discussed for tower-mounted applications where size and weight are important. The heat flux rates necessary for central solar receivers are nearly identical to the design hear fluxes for the compact steam generator. Fabrication of the central receiver is discussed as well as design details and applicable materials.     

Optimal solar energy collector system

The problem of designing solar energy collectors for the delivery of heat at minimum cost is analysed in two different forms. In the first of these, a set of collectors is assumed to be available, each element having different properties uniformly distributed over its area; an optimal design is achieved by a suitable combination of a subset of such collectors. In the second form the collector is designed with a non-uniform, continously varying insulation thickness. The principle of each solution is stated as a theorem. An example of the continuous solution for a flat plate collector is evaluated in the Appendix.     

Integrated collector storage solar water heaters

The Integrated Collector Storage Solar Water Heater (ICSSWH) developed from early systems comprised simply of a simple black tank placed in the sun. The ICSSWH, by its combined collection and storage function suffers substantial heat losses to ambient, especially at night-time and non-collection periods. To be viable economically, the system has evolved to incorporate new and novel methods of maximising solar radiation collection whilst minimising thermal loss. Advances in ICS vessel design have included glazing system, methods of insulation, reflector configurations, use of evacuation, internal and external baffles and phase change materials.     

模块化可翻转太阳能集热器

我公司研制出一种新型实用合理的与建筑结合的一体化、模块化、可翻转太阳能集热器,并申报了实用新型专利。     

Experimental investigation of a domestic solar water heater with solar collector coupled phase-change energy storage

Phase change materials (PCMs) have good properties such as high thermal capacity and constant phase change temperature. Their potential use in solar energy storage is promising. Tests of exposure and constant flow rate are performed to investigate the thermal performance of a domestic solar water heater with solar collector coupled phase-change energy storage (DSWHSCPHES). Due to the low thermal conductivity and high viscosity of PCM, heat transfer in the PCM module is repressed. The thermal performance of the DSWHSCPHES under exposure is inferior to that of traditional water-in-glass evacuated tube solar water heaters (TWGETSWH) with an identical collector area. DSWHSCPHES also performs more efficiently with a constant flow rate than under the condition of exposure. Radiation and initial water temperature have impacts on system performance; with the increase of proportion of diffuse to global radiation and/or initial water temperature, system performance deteriorates and vice versa.     

一种热管平板太阳能集热装置的性能研究

为解决平板大阳能集热装置在冬季的防冻问题,设计建造了热管平板集热装置,并进行了实验测试.在实验中测量了系统的初末状态水温、流量、环境温度、辐照强度等数据.通过对数据的分析拟合出了系统效率与初始水温、环境温度以及辐照强度之间的经验公式,并且以该经验公式为依据对系统全年12个月典型晴天气象条件下的系统效率进行了模拟.结合实...     

Performance of an inverted flat plate solar collector

In this note an analysis of an inverted flat plate solar collector has been presented. Effect of various parameters, namely thickness of the insulation, air conductance between flowing water and top of the bottom insulation, length of the collector and flow velocity of water on the performance of the collector have been studied. Numerical calculations have been made for typical cold day in Delhi, namely 26 January 1980.     

Factors influencing solar energy collector efficiency

The effects of glazing, solar flux, emissivity and absorptivity of the absorber surface on collector performance have been predicted for different plate temperatures (60°C and 100°C). At low solar flux levels (200–600 W m^?2) double- or triple-glazed collectors are superior to single-glazed collectors. For collectors with selective absorber coatings, the optimal number of glazing panes is two. Higher values of absorptivity and lower values of emissivity are more effective for single-glazed than for double-glazed collectors.     

平板太阳集热器防冻结构试验研究

提出利用预留空间结构的防冻方案,并取得了初步研究成果。     

Honeycomb solar pond collector and storage system

An analysis of a honeycomb-stabilized, saltless solar pond as a solar energy collector and long term (spanning seasons) storage system is presented. The solar pond is considered with a nonconvective zone made up of an oil layer and air honeycomb configuration. A heat flow model is developed using the two loss mechanisms (conduction and radiation). The efficiency of heat collection and the storage characteristics of the system are excellent for hot water production and process heat applications.     

Single basin solar still coupled with flat plate collector

This paper presents the transient performance of a single basin solar still coupled with a flat plate collector. The average daily production of distilled water has been found to be 24% higher than for a simple single basin solar still