Waste Heat Recovery and Conversion into Electricity: Current Solutions and Assessment

Yıl 2019, Cilt: 22 Sayı: 1, 1 - 7, 02.03.2019

Mathilde Blaise Michel Feidt

https://doi.org/10.5541/ijot.487951

Cited By: 3

Öz

The main energy consumption sectors are the
residential, industry and transport. In all of them, a part of the energy
consumption is not used and generally rejected as heat in the environment. This
is named the waste heat. Firstly, the main way is to optimize the process to
reduce the fuel consumption. Then, if there is a residual waste heat, a
valorization way is to convert this heat into electricity. Some technologies
are developed. The main technology is the Organic Rankine Cycle engine. Then, a
new concept, named Turbosol, is based on the quasi-isothermal expansion of a
water and oil mixture in a nozzle. Some piston engines are also developed,
based on Stirling, Ericsson and Joule cycles. All these technologies are named
externally heated engines. Some other research studies concern the
thermo-electric effect and the thermo-magnetic effect. In this article, a
non-exhaustive list, with description and comments on these technologies is
proposed. The aim is to assess the potential of them and identify the current
limits. To compare the different technologies in first law efficiency terms is
not sufficient. Some new criterions are proposed. The first consideration is to
assess the heat rate consumption referred to the heat rate available. To assess
the quality of waste heat to power conversion, it is pertinent to evaluate the
power output divided by the available heat rate. Then, because of the second
law, it is pertinent to evaluate the exergy recovery ratio. These new waste
heat criterions are compared to the classical first law efficiency in different
cases. Then, the main current issue is to produce enough electrical power
output to ensure the profitability. Some thermo-economic considerations are
proposed, including the impact of a waste heat taxation.

Anahtar Kelimeler

Thermodynamics, energy, exergy, sustainability

Kaynakça

• Andrea Lazaretto
• Diogo Queiros-Conde
• Lavinia Grosu