How do we go from waste heat to electrical power, the turbine edition

Research on a certain turbine in a cycle that convert heat into electrical power, may in time contribute to developing cost-effective turbines. This is a stepping stone in increasing the return on renewable energy sources.

A picture of a man with a turbine model.
A model of the turbine which will be used in experiments for more knowledge on converting heat to electrical power. Photo: Maren Agdestein/NTNU

This is a blog post. The opinions expressed here are those of the author.

Written by
a man
Lasse Borg Anderson PhD Candidate

My research concerns a certain component in a cycle that convert heat into electrical power, namely an axial turbine in an organic rankine cycle (ORC). For now, the turbine in these cycles performs poorly when the heat source is of moderate temperatures (100-400 degree Celsius), and we would like to change this.

Combining testing and numerical methods

My research will include both experimental work and numerical modelling. We have just received a new rig here at NTNU, which we will use to test an axial turbine. See video below:

The tweet text below says: “We have been waiting for this: 4,4 tonnes is lifted one floor up in Varmetekniske laboratorier at @NTNU. The rig will help the researchers find out more about how to use waste heat to make electricity. Related to the infrastructure project HighEFF.”

The experimental work is thought to focus on behavior of the turbine at off-design conditions, and then check how this coincide with the numerical model developed. I already have a numerical model from a previous PhD, that gives an optimized design of a turbine under given conditions. The plan is to develop this code to estimate efficiency under off-design conditions, and possibly give an optimized design for a range of operating conditions.

We have too little information on these types of turbines

Experimental work is important to increase the quantity of available data on turbines in ORCs, which can be considered as slim. At least when looking at off-design performance. This can be used to tune loss models used for numerical modelling, thus increasing the accuracy of such models. The last topic, namely to give an optimized design for a range of operating conditions could help to provide a better turbine over an annual time perspective rather than just under one operating condition.

A picture of the inside of a turbine model.
The inside of the turbine is displayed in this model. Photo: Maren Agdestein/NTNU

Renewable energy and heat recovery

This work is a part of a project which aims to develop cost-effective turbines for power system (DEXPAND). In this way, it could get more profitable to acquire such systems and to utilize more waste heat. Other proposed applications are geothermal energy, solar energy and biomass combustion. Consequently, if the project accomplishes its goals, it could contribute to increase the return on renewable energy sources in addition to recover heat from industrial processes.

More about me

Before starting my PhD, I finished my masters in energy and environmental engineering here at NTNU. The topic of my master was quite different, as it concerned electrolysis of liquid ammonia, but it was nevertheless a good experience. I am not from Trondheim but from a village called Moelv, between Lillehammer and Hamar.