TCHE

The ThOR Cycle Heat Engine is a high efficient steam engine. Depending on specific design aspects, it will have an efficiency of between 50% and 84%. The estimated cost to develop the first prototype is around $470,000 ($235k capital injection and $235k Grant Funding). Estimated development time is 12 months.

To place it in perspective, coal fired power plants operate on the modified Rankine thermodynamic cycle.The efficiency is dictated by the parameters of this thermodynamic cycle. The overall coal plant efficiency ranges from 32 % to 42 %. This is mainly dictated by the Superheat and Reheat steam temperatures and Superheat pressures. Most of the large power plants operate at steam pressures of 170 bar and 570 °C Superheat, and 570 ° C reheat temperatures. The efficiencies of these plants range from 35 % to 38 %. Super critical power plants operating at 220 bar and 600/600 °C can achieve efficiencies of 42 %. Ultra super critical pressure power plants at 300 bar and 600/600 °C can achieve efficiencies in the range of 45% to 48 % efficiency. These systems are extremely dangerous due to the high steam pressure and not feasible to build on small scale.

For current small waste heat recovery generators (around 100kW) operating under 300 Deg. C, system efficiencies are in the region of 12%. ThOR stands for (Thermally Optimised Recovery). The technology is based around a low pressure, low temperature reaction turbine. Due to the low operating pressure, one can recover most of the exhaust heat from the turbine by recompressing the exhaust steam without having to first condense the exhaust steam and thereby discarding around 60% of the latent heat, resulting in very large efficiency gains compared to any other steam cycle. In comparison, the ThOR cycle operates at around 4 Bar(a) compared to other large systems operating at above 170 Bar. It is not only more efficient, but also much, much safer.

The ThOR Engine relies on known scientific and engineering knowledge and is therefore only a matter of engineering, not like the JTS which involves controversial “new” science. This is thus a much lower risk, yet with an immediate large market.

Let’s say we only achieve 50% efficiency (bottom end of the expected performance scale), and fit the unit to a 100 kVA (100 kW) diesel generator. The diesel engine has an efficiency of around 33%, whereby roughly 33% is absorbed by the coolant and 33% of the latent heat generated is lost via the exhaust stream. So, to be able to generate 100kW, the engine needs to burn around 300kW of fuel. 100 kW of heat is available for waste recovery, of which 50% is converted back into electrical energy, turning the 100 kVA Generator into a 150 kVA one.

Tests conducted (which I participated in) earlier this year at the University of South Australia showed that a diesel generator operated with a 80 kVA load, generated 120 kW of recoverable heat from the exhaust. If we achieve an efficiency in the middle between 84% and 50%, i.e. 67%, then the 120kW available heat is converted to 120 x 0.67 = 80.4 kW, thus doubling the generator’s standard output from 80 kW to 160 kW.