Gary Kovacik

Thermophotovoltaics for Combined Heat and Power Using Low NOx Gas Fired Radiant Tube Burners

Three new developments have now occurred, making economical TPV systems possible. The first development is the diffused junction GaSb cell that responds out to 1.8 microns producing over 1 W/cm2 electric, given a blackbody IR emitter temperature of 1250 C. This high power density along with a simple diffused junction cell makes an array cost of

Characteristics of rapid hydropyrolysis of coals in a free fall pyrolyser

0.50 per Watt possible. The second development is new IR emitters and filters that put 75% of the radiant energy in the cell convertible band. The third development is a set of commercially available ceramic radiant tube burners that operate at up to 1250 C. Herein, we present near term and longer term spectral control designs leading to a 1.5 kW TPV generator / furnace incorporating these new features. This TPV generator / furnace is designed to replace the residential furnace for combined heat and power for the home.

Design and Performance of a Prototype Thermophotovoltaic System

Abstract Five non-caking and two caking coals were pyrolysed rapidly using a free fall pyrolyser in a hydrogen stream at atmospheric pressure and at temperatures up to 1233 K, with a heating rate of ≈6000 K s −1 . Sequential changes in the yield of volatile matter and char internal surface area were followed for several treatment times, from ≈0.1 to 0.4 s. The pyrolysis rate was determined by considering changes in particle temperature, diameter and apparent density. Average rate constants of pyrolysis were correlated with the increasing ratio of internal surface area in the early stage of pyrolysis. Rapid-hydropyrolysis char was more favourable for gasification than slow-heating pyrolysis char.

Design and Preliminary Testing of a Prototype Thermophotovoltaic System

A prototype thermophotovoltaic (TPV) system, utilizing a cylindrical radiant burner, and GaSb cells, was assembled and tested. A unique combination of nine-layer dielectric and quartz-214 optical filtering components was utilized to minimize circuit heating, and increase emitter temperature. An evaluation of the performance of each of the spectral filtering components, and a mapping of energy losses throughout the system are provided for burner firing rates ranging from 6 kW to 9 kW. Fuel to electric conversion efficiency for this prototype TPV system was found to increase linearly from 1.2% at 6 kW to 1.5% at 9 kW. This corresponded to power densities ranging from 0.07 W/cm 2 at 6 kW to 0.13 W/cm 2 at 9 kW Areas that require additional improvement in order to increase system efficiency are addressed.

Controlling solid oxide fuel cell operation

Thermophotovoltaics (TPV) is technology similar to conventional solar photovoltaics, which have been in existence for over 50 years. The main difference between traditional solar photovoltaics and TPV is that, instead of the sun, an “emitter” is used to produce light, which is then converted into electricity by the TPV system. This emitter is heated via combustion or some other method until photons are ejected. Although the light utilized in the TPV system is not as energetic as that from the sun, the fact that the TPV cells can be placed in close proximity to the source (compared with the distance to the sun) increases the intensity of the light received by the cells. This results in a higher power production density than is possible with traditional solar photovoltaic systems. One estimate of maximum achievable output power density for TPV systems is 5W/cm2 , approximately 500 times that of a traditional solar PV system. Researchers in this field have already demonstrated power densities of 1.5W/cm2 . Other attractions of TPV systems include fuel versatility, compact size, silent sun-independent operation, and low maintenance costs. A TPV test station has been assembled at the Alberta Research Council in Canada. A general overview of the background technology and system components will be presented, as well as preliminary experimental results. Areas that require additional improvement in order to increase system efficiency will also be addressed.Copyright