Optimisation of Built-in Storage Solar Water Heater for Scottish Weather Conditions

  The ICSSWH (Integrated Collector Storage Solar Water Heater), apart from being the
oldest is also the most economical means of solar water heating. The effect of
modifications in the collector geometry has frequently appeared in the literature, and
over the time, has resulted in different designs. These designs differ mainly on the site
of installation as well as the target application. A novel design created by Professor T
Muneer at Napier University, utilizes fins inside the storage tank to improve the heat
transfer. The reported field tests of the fin type ICSSWH have indicated a 10 %
improvement in the solar fraction compared to unfinned.
As ICSSWH is the lowest cost, it presented a possible solution for the Scottish market
where Energy Saving Trust estimates that 50% of hot water demand of a household
can be met through solar water heating.
In the present research program, two prototype collectors (one with- and one without
fins) were fabricated at Napier University by the author. The collectors were then
tested in the laboratory on identical experimental schemes to determine their
respective performance. Simulations based on analytical modelling were then
undertaken, using numerous experimental data for validation that were obtained
during the course of the present work. A high degree of conformance was noted
between the two. Furthermore, for a deeper insight, Computational Fluid Dynamics
(CFD) analysis was performed.
This research focuses on the qualitative and quantitative assessment of the heat
transfer due to the fins. The difference in the performance with respect to the change
in tilt angle was also studied. This study can therefore be utilised for developing solar
water heating systems for any given location. Note that there is an intrinsic link
between the latitude and inclination angle of the collector plate. The nocturnal loss from the collector is the principal factor that has inhibited the wide
spread use of the ICSSWH. The remedies to abate this problem have therefore been
attempted. In addition to that, the collectors have to be integrated with the domestic
hot water supply system and plumbing considerations have to be incorporated within
the overall design. The supply circuits were worked out and the measures for freeze
and boil protection were devised.
The optimization of any system is an intrinsic task particularly when several variables
are involved. On the basis of the obtained results from simulations and experiments,
the influential design variables were identified. The values for these variables which
lead to the optimal design in terms of thermal performance were assessed while
keeping the overall manufacturing cost of the collector as low as possible.
Recommendations for future work have also been presented.

  • Dates:

    2004 to 2007

  • Qualification:

    Doctorate (PhD)

Project Team