The man behind the new generation ORC process

The late Arne "Pump-Arne" Jonsson was the man behind the ECT system. For many years he was a respectable consultant to the aerospace and pump industries in Sweden. His designs were well proven, efficient in operation and enduring long lasting life cycles. 

Arne was expert in energy systems and mechanical calculations, an engineer driven by virtue of excellence to optimize his solutions - from design of impellers and turbines to production. His motto was "All large as well as tiny parts have to be optimized to have a reliable system. And since we have few components we can keep the cost down." 

Early 2000 Arne took the first steps to solve the problem of poor efficiency of the ORC (Organic Rankine Cycle) process at a small temperature difference when using waste heat as source. The solution was the ECT ORC 2.0 Process of an astonishing double the output as compared to a standard ORC system. 

"By the ECT system, more of the available heat is converted into mechanical work than ever possible by the standard ORC process. That´s why you will be much better off".

The Technology

To be able to optimize the complete system and electrical output you first need to understand the heat source. This is best done with a so-called  temperature profile. It´s a graph showing temperature (Y-axis) and heat transfer (X-axis).

The Temperature Profile

To the left a Temperature Profile for waste heat is displayed. Here for a diesel engine for a ship. 

In this example heat goes from 330 to 50 degrees centigrade. And the heat transfer up to 40 MW. 

Source: Maria Jonsson, Advanced Power Cycles with Mixtures as the Working Fluid, Dr Thesis, KTH 2003. Graphics©: ECT Power AB.

The standard ORC process

Once you have the temperature profile you can start the design of the internal ORC circuit. (Organic Rankine Cycle). 

In a normal ORC process heat exchanges are used for pre-heating, evaporation and super heating of the fluid. This generates steam for the turbine. When the fluid leaves the turbine it  is cooled in a condenser (also a heat exchanger). 

The ECT ORC 2.0 process

The new integrated multi-pressure ORC process, ORC 2.0, improves the heat transfer process (pat.pend.) with more than 100 %. 

Seen in the diagram the "used" area under the heat source is much larger=more heat transferred compared the the standard process above. This is a key to the increased electrical output. 

The heat transfer process in combination with own designed high performance turbine (ŋ around 90%) and pump gives the high output (also pat.pend.)