Study and Analysis of Different Absorber Geometry of Compound Parabolic Solar Collector and its Effect on Thermal Efficiency for Heating Water for Sanitary Use

Abstract

This project is focused on carrying out a study of the absorber geometry of the parabolic solar collector compound for heating water for sanitary use, to evaluate the temperature gradient between the inlet and outlet of the water of this concentraDDDtor collector, and the efficiency achieved according to the absorber configuration to later compare it with collectors with a conventional flat absorber surface. The parabola of the reflector of the composite parabolic solar collector was obtained considering the circular absorber, with a concentration ratio of 4 plus 10% of this, to consider a truncation of the reflector, the circular absorber was configured with a small absorber plate of aluminum which has a thermal conductivity of 401 W /mK The values obtained experimentally in the collector were based on the data collected in the field files. It was considered to experience the heating of water on different days with the climatic conditions, cloudy, partially cloudy and sunny, with a totally clear sky. The water heating tests were carried out with two types of geometric configuration of the absorber of the composite parabolic solar collector; circular absorber and configured circular absorber, with which a water outlet temperature of 61 ° C and 76 ° C and a thermal efficiency of 60% respectively were obtained, these results were presented taking into account a climatic condition (sunny day) approximately the same for the two absorber configurations, and with average values of wind speed, ambient temperature and solar radiation.

Introduction

I. INTRODUCTION

In the world, in recent years there has been a notable increase in solar thermal energy installations; Technological advances allow the manufacture of better quality systems at a lower cost and society is understanding the need to replace fossil fuels.

Since its first invention, several decades ago, various forms of solar thermal collectors have been developed, ranging from flat collectors to parabolic collectors and heliostats. For this reason, the use of solar thermal energy, beyond being an ecological alternative, has become an economically attractive and competitive technology in many countries.

Research has been carried out to promote the development of clean and renewable energy projects such as wind, hydroelectric, biomass and solar energy. an input for the implementation of technologically efficient production processes such as systems for water heating and swimming pool heating, all this through clean energy and under conditions of strategic advantage for our country due to the radiation it receives due to its geographical position

II. PROBLEM DEFINITION

The development of this research is necessary since it seeks to improve the capture of solar energy, studying the geometry of the absorber of the composite parabolic solar collector since it is one of the most used devices, especially due to its great capacity in energy concentration. The surface of the receiver or absorber can have different shapes; the most used form is the configuration with a flat receiver, on the other hand with the cylindrical form the face to the sun can capture direct radiation and the part hides the radiation by reflection. If not carried out, we will not be able to verify if this device will reach significantly higher temperatures, minimize losses, and thus achieve adequate efficiency in heating water for sanitary use.

Will the application of the absorber geometry of the composite parabolic solar collector allow us to achieve significantly higher temperatures for heating water for sanitary use?

With the development of this study, will an acceptable efficiency be determined for heating water for sanitary use using solar radiation?

Will this study know the energy advantage when configuring the absorber of the composite parabolic solar collector?

III. ANALYSIS AND INTERPRETATION OF RESULTS

The water heating tests were carried out using a parabolic solar collector composed of a circular absorber (recommends copper pipe as a material for the circulation of the working fluid).

It was considered to experience the heating of water on different days with the following climatic conditions:

1. Cloudy
2. Partial cloudy
3. Sunny, with a totally clear sky.

A. Water Heating Using The Circular Absorber

 The climatic conditions: partially cloudy, sunny and cloudy, respectively.

The outlet temperature of the water from the solar collector was analyzed, which depends on the temperature reached at the focus of concentration of the composite parabolic solar collector, which is the circular absorber.

B. Variation In Temperature Between The Water Inlet And Outlet Of The Solar Collector On A Cloudy Day

The outlet temperature for this climatic condition presented an average of 30.2 ° C, while the average inlet temperature that oscillates 17.2 ° C, having a temperature variation of 13 ° C.

The configuration of the composite parabolic solar collector concentrates radiation through the use of multiple reflections as well as direct interception, in order to have a greater benefit from solar energy which is naturally available and thus be able to guarantee greater thermal efficiency in solar systems.

Conclusion

The variation in water temperature between the inlet and outlet of the collector was unstable in the test periods, since as this type of collector is a radiation concentrator, it produces instantaneous temperature increases. The water outlet temperatures of the composite parabolic solar collector with the circular absorber exceeded 60 ° C on a sunny day, with a totally clear sky. On days with little presence of sun, partially cloudy, the outlet temperature of the water from the solar collector was around 50 ° C, and on a cloudy day it reached temperatures higher than 30 ° C. On days with partially cloudy and sunny weather conditions, the water outlet temperature was within the indicative range of the composite parabolic solar collector, which is 60 ° C to 240 ° C. The thermal efficiency achieved in the composite parabolic solar collector with the circular absorber reached a value of 67.71% higher by 12.51% than the value of 55.2% of thermal efficiency of the conventional flat surface solar collector for a sunny day. The thermal efficiency in the parabolic solar collector composed with the circular absorber for days, partially cloudy and cloudy were 75.62% and 58.8% respectively, which exceeded the thermal efficiency value of the conventional flat absorber surface solar collector by 20.42% and 3.6%.

References

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Copyright

Copyright © 2022 Nishant Kumar, Dharamveer Singh. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.