Abstract
Renewable energy systems currently play and will play a primary role in reaching
the targets of the Montreal protocol and its recent amendments to keep temperature
growth on earth within limits. Understanding and optimising heat and mass transfer
in these systems and their components is crucial to convert, store and extract
the maximum energy possible. Today, numerical simulations based on theoretical
approaches and experimental validation mutually coexist depending on each other
providing necessary information to reach the environmental goals.
First, an overview on those renewable energy systems is given, where understanding
heat and mass transfer plays a vital role. Isothermal turbulent
ows on large
and small scale, unsteady
ows with heat transfer and transient
ows with mass and
heat transfer are covered in the work. In these areas, three important applications
have been selected: solar collectors, absorption reactors and heat pumps. Heat and
mass transfer mechanisms are investigated both numerically and experimentally.
Especially for air-to-water heat pumps, acoustic emissions further enhanced by the
subsequent frosting of the outdoor evaporator are becoming a concerning issue,
possibly impeding the rapid growth of the necessary installation of these types of
heat pumps. Therefore an additional focus in this thesis is set to frosting and its
impact on the acoustic signatures of heat pumps. Providing a link between
uid
mechanics and acoustic waves, the Lighthill acoustic analogy is utilised to give an
overview of dipolar and quadrupolar aero-acoustic sources and their radiated far
eld sound pressure eld.
The second part of the habilitation theses is formed by the core journal publications
focussing on heat transfer in solar collectors and combined heat and mass
transfer in rotating drum absorbers. Furthermore understanding and optimising
production processes with respect to
uid mechanics and heat transfer add largely
to the capability to reach the global environmental goals. Closing the loop to the
recent studies of acoustical emissions in heat pumps, numerical work in the eld of
aero-acoustics has been included in this thesis. Finally, the publication in preparation
on heat exchanger frosting is attached.
Originalsprache | Englisch |
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Gradverleihende Hochschule |
|
Publikationsstatus | Veröffentlicht - 2018 |
Research Field
- Ehemaliges Research Field - Digitalisation and HVAC Technologies in Buildings