Flat-Plate Solar Collector in Transient Operation: Modeling and Measurements

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Ahmad M. Saleh ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Differential Equations ◽  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Ambient Air ◽  
Fluid Temperature ◽  
Ambient Conditions ◽  
Flow Rates ◽  
Collector System ◽  
Nodal Model

This paper describes a mathematical model for simulating the transient processes which occur in liquid flat-plate solar collectors. A discrete nodal model that represents the flat-plate solar collector's layers and the storage tank is employed. The model is based on solving a system of coupled differential equations which describe the energy conservation for the glass cover, air gap, absorber, fluid, insulation, and the storage tank. Inputs to the model include the time-varying liquid flow rate, incident solar radiation, and the ambient air temperature, as well as the volume of liquid in the storage tank and initial temperature of the system. The system of differential equations is solved iteratively using an implicit, finite-difference formulation executed with Matlab software. In order to verify the proposed method, an experiment was designed and conducted on different days with variable ambient conditions and flow rates. The comparison between the computed and measured results of the transient fluid temperature at the collector outlet shows good agreement. The proposed method is extremely general and flexible accounting for variable ambient conditions and flow rates and allowing for a geometrical and thermophysical description of all major components of the solar collector system, including the storage tank. The validated, general model is suitable to investigate the effectiveness of various components without the necessity of carrying out experimental work, and the flexible computational scheme is useful for transient simulations of energy systems.

Flat-Plate Solar Collector in Transient Operation: Modeling and Measurements

2013 ◽  
Author(s):  
Ahmad M. Saleh ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Solar Radiation ◽  
Differential Equations ◽  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Ambient Air ◽  
Time Varying ◽  
Ambient Conditions ◽  
Flow Rates ◽  
Flat Plate Solar Collector

Solar energy is a viable alternative to limited fossil fuel resources. One of the simplest and most direct applications of this energy is the conversion of solar radiation into thermal energy with a flat-plate solar collector which can be used in water-heating systems. This paper presents a mathematical model for simulating the transient processes which occur in liquid flat-plate solar collectors. A discrete nodal model that represents the flat-plate solar collector’s layers and the storage tank is employed. The model is based on solving a system of coupled differential equations which describe the energy conservation for the glass cover, air gap, absorber, fluid, insulation, and the storage tank. Inputs to the model include the time-varying liquid flow rate, incident solar radiation, and ambient air temperature, as well as the volume of liquid in the storage tank and initial temperature of the solar collector and tank. The system of differential equations is solved iteratively using an implicit, finite-difference formulation executed with MATLAB software. In order to verify the proposed method, an experiment was designed and conducted on different days with variable ambient conditions and flow rates. The comparison between the time-varying computed and measured fluid temperature at the collector outlet shows good agreement. The proposed method is extremely general and flexible accounting for variable ambient conditions and flow rates, as well as allowing for a geometrical and thermophysical description of all essential components of the solar collector system, including the storage tank. The validated and verified, general model is suitable to investigate the effectiveness of various components without the necessity of carrying out experimental work, and the flexible computational scheme is useful for transient simulations of energy systems.

Design, Implementation, and Evaluation of Thermal Performance of a Thermosiphon Flat-Plate Solar Collector for Water Heating in Ecuadorian Coastal Region

2017 ◽  
Author(s):  
Carola Sánchez ◽  
José Macías ◽  
Jonathan León ◽  
Geancarlos Zamora ◽  
Guillermo Soriano
Keyword(s):  
Flat Plate ◽  
Thermal Performance ◽  
Solar Collector ◽  
Storage Tank ◽  
Hot Water ◽  
Attractive Alternative ◽  
Local Market ◽  
Water Heating ◽  
Water Storage Tank ◽  
Flat Plate Solar Collector

Passive solar water heating (SWH) is a convenient method to meet domestic hot water requirements in rural areas, where electricity may not be available or fuel supply might be limited due to difficult access. In this work, a low-cost thermosiphon flat-plate solar collector alternative is presented. The design was purposely limited to materials and recyclable products widely available in the local market, such as Tetra Pak, plastic bottles, and polypropylene (PP) fittings and pipes. Since PP is a thermoplastic polymer, a poor heat conductor, it was necessary to ensure a suitable system isolation to obtain an optimum thermal performance, comparable to commercial solar collectors. The design was built and tested in Guayaquil, Ecuadorian coastal city. Six inexpensive temperature sensors were placed at the entrance and exit of the collector, on the flat-plate and inside the hot water storage tank. Data was recorded using an Arduino single-board computer and later analyzed with the data gathered via weather station. The implementation costs of the system are approximately US$300, the overall performance during January 2017 fluctuated between 54% and 23%, and the storage tank temperature range varied from to 46°C to 33°C. Due to its reliability and affordable cost, the SWH system is an attractive alternative to an Ecuadorian commercial solar flat plate collector, which price is set between US$600 and US$700, it has an efficiency around 60%, and the average annual storage tank temperature is 62°C.

Using a Windbreak to Improve the Thermal Performance of a Flat Plate Solar Collector: A Feasibility Study

2011 ◽  
Author(s):  
Saeed Moaveni ◽  
Michael C. Watts
Keyword(s):  
Flat Plate ◽  
Heat Loss ◽  
Forced Convection ◽  
Thermal Performance ◽  
Solar Collector ◽  
Large Scale ◽  
Ambient Air ◽  
Absorber Plate ◽  
Wide Range ◽  
Flat Plate Solar Collector

During the past few decades, a wide range of studies have been performed to improve the performance of flat plate solar collectors by either reducing the heat loss from a collector or by increasing the amount of solar radiation absorbed by the absorber plate. Examples of these studies include adding transparent honeycomb to fill the air gap between the glazing and absorber plate to reduce convective heat loss, replacing the air in the gap by other gases such as Argon, Krypton, Xenon and Carbon Dioxide, or adding a chemical coating such as Copper Oxide to increase absorbtance and reduce the emittance of the absorber plate. While these methods improve the collector’s efficiency, they focus primarily on limiting the natural convection that occurs in the collector cavity, or on improving the optical properties of the absorber or glazing. None of these studies have addressed the problem of heat loss due to forced convection to the surrounding ambient air in any detail. Yet, research has shown that forced convection will contribute significantly to the heat loss from a collector. Windbreaks have traditionally been used to direct wind to protect farmland, and to direct wind drifts and sand dunes. Windbreaks also have been shown to provide protection for homes from winter winds which result in reduced heating costs for buildings. While windbreaks have been traditionally used for large scale applications, there is reason to believe that similar benefits can be expected for scaled down applications such as adding a windbreak along side of a flat-plate solar collector. In this paper, we examine the feasibility of using a windbreak to provide a flat plate solar collector protection from the wind in order to improve its performance. A series of experiments were performed wherein the thermal performance of two flat-plate collectors — one without a windbreaker and one with a windbreaker — were measured. The results of these experiments are reported in this paper and the need for further studies to explore different windbreak configurations is discussed.

scholarly journals Heat transfer in a low latitude flat-plate solar collector

2012 ◽  
Vol 16 (2) ◽  
pp. 583-591
Author(s):  
C.O.C. Oko ◽  
S.N. Nnamchi
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Solar Collector ◽  
Design Parameters ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Port Harcourt ◽  
Collector Efficiency ◽  
One Year ◽  
Flat Plate Solar Collector

Study of rate of heat transfer in a flat-plate solar collector is the main subject of this paper. Measurements of collector and working fluid temperatures were carried out for one year covering the harmattan and rainy seasons in Port Harcourt, Nigeria, which is situated at the latitude of 4.858oN and longitude of 8.372oE. Energy balance equations for heat exchanger were employed to develop a mathematical model which relates the working fluid temperature with the vital collector geometric and physical design parameters. The exit fluid temperature was used to compute the rate of heat transfer to the working fluid and the efficiency of the transfer. The optimum fluid temperatures obtained for the harmattan, rainy and yearly (or combined) seasons were: 317.4, 314.9 and 316.2 [K], respectively. The corresponding insolation utilized were: 83.23, 76.61 and 79.92 [W/m2], respectively, with the corresponding mean collector efficiency of 0.190, 0.205 and 0.197 [-], respectively. The working fluid flowrate, the collector length and the range of time that gave rise to maximum results were: 0.0093 [kg/s], 2.0 [m] and 12PM - 13.00PM, respectively. There was good agreement between the computed and the measured working fluid temperatures. The results obtained are useful for the optimal design of the solar collector and its operations.

scholarly journals Comparative Analysis of Exergy and Efficiency for Stratified Thermal Storage Tank with Solar Flat Plate and Evacuated Tube Collectors

2016 ◽  
Vol 855 ◽  
pp. 114-118 ◽  
Author(s):  
Sukruedee Sukchai ◽  
Yodthong Mensin ◽  
Wikarn Wansungnern
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Evacuated Tube Solar Collector ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

In recent years, solar water heating technology has got the major importance in water heating applications. For the efficient and effective working of solar water heaters, storage of the hot water is the main issue in this water heating technologies. This paper mainly presents the exergy and efficiency comparison between the solar flat plate water heater and evacuated tube water heater. A five level stratified thermal storage tank is designed and developed for this analysis. At each level of the tank, temperature of the water is collected for each one hour interval from 9:00 to 16:00 hours in both cases and the overall exergy and efficiency of the two water heaters were calculated. The average efficiency of all the levels for flat plate and evacuated tube collectors are 7.91% and 8.20% respectively. The overall system efficiency is obtained as 39.54% for flat plate and 41.00% for evacuated tube solar collector. At each level exergy is calculate for both systems and the average exergy of all the levels for flat plate collector is 4.243 kW and for evacuated tube solar collector is 4.371 kW.

Unsteady thermotechnical model of a closed flat plate solar collector–storage tank system

2017 ◽  
Vol 53 (4) ◽  
pp. 303-305
Author(s):  
Sh. I. Klychev ◽  
O. Kh. Nizomov ◽  
D. E. Kadyrgulov
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Tank System ◽  
Flat Plate Solar Collector
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