0
research-article

APPLICABILITY OF HEAT MIRRORS IN REDUCING THERMAL LOSSES IN CONCENTRATING SOLAR COLLECTORS

[+] Author and Article Information
Vikrant Khullar

Mechanical Engineering Department, Thapar Institute of Engineering and Technology, Patiala - 147004, Punjab, India
vikrant.khullar@thapar.edu

Prashant Mahendra

Mechanical Engineering Department, Thapar Institute of Engineering and Technology, Patiala - 147004, Punjab, India
pm133361@gmail.com

Madhup Kumar Mittal

Mechanical Engineering Department, Thapar Institute of Engineering and Technology, Patiala - 147004, Punjab, India
madhup.mittal@thapar.edu

1Corresponding author.

ASME doi:10.1115/1.4040653 History: Received October 31, 2017; Revised June 02, 2018

Abstract

In the present work, a novel parabolic trough receiver design has been proposed. The proposed design is similar to the conventional receiver design except for the envelope and the annulus part. Here, a certain portion of the conventional glass envelope is coated with Sn-In2O3 and also Sn-In2O3 coated glass baffles are provided in the annulus part to reduce the radiative losses. The optical properties of the coated glass are such that it allows most of the solar irradiance to pass through, but reflects the emitted long wavelength radiations back to the absorber tube (Sn-In2O3 coated glass is referred to as 'transparent heat mirror'.) Thus, effectively reducing the heat loss area and improving the thermal efficiency of the solar collector A detailed one dimensional steady state heat transfer model has been developed to predict the performance of the proposed receiver design. It was observed that while maintaining the same external conditions (such as ambient/initial temperatures, wind speed, solar insolation, flow rate, concentration ratio etc.) the heat mirror-based parabolic trough receiver design has about 3-5% higher thermal efficiency as compared to the conventional receiver design. Furthermore, the heat transfer analysis reveals that depending on the spatial incident solar flux distribution, there is an optimum circumferential angle (? = ?optimum, where ? is the heat mirror circumferential angle) up to which the glass envelope should be coated with Sn-In2O3. For angles higher than the optimum angle, the collector efficiency tends to decrease owing to increase in optical losses.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In