Design and Performance Evaluation of Building Integrated Solar Technology for Greywater Recycling and Thermal Gain
- Author(s): Kagey, Henry
- Advisor(s): Hermanowicz, Slawomir W
- et al.
Developing sustainable building technologies to confront the growing pressure of
essential resource scarcity is an important task for civil and environmental
engineers in the 21st century. This dissertation describes the design,
experimentation, and performance modeling of a multi-physics, building integrated,
solar-powered panel system for on-site greywater recycling and thermal gain for
interior climate conditioning. The hybrid CORE (Cylindrical Optical Reactive
Cylinders) panel type is novel in itself, using wave-guides to support titania
photocatalyst and distribute UV light for inactivation and mineralization of
contaminants, which has not been studied to date, particularly in a multi-scale
Several research directions are detailed, from determining the potential for
interception mechanics in the cylinder bank of waveguides, to the use of
mathematical optimization for performance analysis. In chapter II, Finite Element
Analysis on the micro-scale is used to develop a new correlation for particle capture
of cylinder banks in non-creeping laminar flow. In chapter III laboratory
experimentation on a CORE prototype is detailed in order to estimate reaction rates
under solar conditions and determine the efficacy of the optical waveguides for
stimulating mass transfer in a turbid medium. In chapter IV the NSGA-II algorithm
for multi-objective optimization is employed to assess the influence of multiple
parameters on the mass and heat transfer performance of the panel.
A novel correlation for particle interception in cylinder banks at moderate flow is
given, as well as a simplifying rule of thumb for engineering design purposes.
However, it is also shown that particle interception does not contribute
meaningfully to disinfection in the CORE panel. The reaction rate for the CORE
panel type is determined in the lab: the results show pseudo-zero order kinetics and
an over all slow reaction proportional to the Reynolds number on the order of 1e-4.
A correlation for reaction potential of individual cylinders developed via Chilton-
Colburn analogy from Žukauskas’ work on heat transfer in cylinder banks is shown
to compare well with the experimental results, matching exactly at Re 350. It is also
shown that the photocatalytic response is predominantly due to the effect of
waveguide UV transmission.
The performance evaluation of the CORE panel in the pilot scale simulation in
Berkeley, CA. using the NSGA-II genetic algorithm for the multi-objective studies on
efficiency and output showed tendency for maximizing cylinder diameter and thus
solid fraction, tilt generally pushed towards a 45 tilt from the vertical, and that
CORE could function with a relatively thin over all profile of about 5cm. The
maximum daily output of recycled greywater for a 1m2 panel over a year was 87L, a
relevant contribution to reuse of an individual’s daily grey water production. The
panel system functions best as building added system on the roof, but could function
as building integrated with specific modifications to the catalyst to increase
photosensitization. Further research is required in the direction of multi-parameter
optimization both to incorporate more parameters and design constraints (such as
the effect of flow rate and solid fraction on energy return) and as a design tool to
estimate context dependent design requirements.