Wednesday, November 28, 2012

Research update


Next week, I’ll attend Solar2012, the annual conference of the Australian Solar Energy Society.  It will be, in fact, the 50th annual such conference, which is a wonderful achievement for the Society.  I’ll present my recent simulations on passive solar heat collection, the evaporation engine and pebble bed thermal storage.

The title and abstract for my peer-reviewed paper are:

Passive solar power generation with air-blown thermal storage

A simulation study is presented for air-blown thermal storage in a solar thermal power station powered by passive heat collection under transparent insulated canopies.  The principal objective of this study is to investigate the round-trip efficiency of thermal storage in a pebble bed.  In the proposed system, heat energy is converted to power by a new heat engine based on evaporative cooling of hot air at reduced pressure.

The work examines the performance of the canopy/engine/storage system over representative days each month for a full year.  Useful heat reclaimed from the storage system is typically about 95% of the useful heat input, less small additional losses at the walls and ducts of the storage system.  Because the heat reclaimed has a smoother daily temperature distribution than the heat gathered by the canopy, there is another 5% penalty in conversion of heat into power.  For the configuration used in this study, the power output using storage is 88% of what would be obtained without storage.  This estimate includes modest losses due to pumping and heat transfer at walls and ducts.  Coarse economic evaluations indicate that storage would reduce the Levelised Cost of Electricity by 27% and increase the Capacity Factor of the engine by 88%.

Since I became interested in pebble bed thermal storage about 18 months ago, I’ve become progressively more enthusiastic.  The round-trip efficiency of pebble bed storage is excellent as I have shown in the Solar2012 conference paper, parasitic losses are manageable, and the materials are cheap and should be good for a very large (infinite?) number of cycles.  My previous work on pebble bed storage is highlighted here and here.

What next?

In recent months, I’ve been working on a new concept for solar thermal power generation.  I call this BRRIMS, which stands for Brayton-cycle, Re-heated, Recuperated, Integrated, Modular and Storage-equipped.  Last week I lodged a provisional patent application for the concept, and I’m about to embark on a fresh round of door-knocking of potential investors.  I’m also going to make a thorough revision of the web site for my company, Sunoba Pty Ltd (www.sunoba.com.au).

In the near future, I’ll provide details of BRRIMS on this blog.  For the moment, however, I invite you to get in touch if you like to have a conversation about issues that I have mentioned here.

Dedication

As I was preparing this blog post, it occurred to me that today is the 6th anniversary of the death of my mother, Gwyneth Marjorie Barton, née Evans, 1915-2006.  My mother was extremely influential to my development, and it is with gratitude that I dedicate this blog post to her memory.

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