3. ABSTRACT
• This report highlights the domestic water heating system transient
behavior in order to bring out the effect of the series or parallel
connection of a set of flat plate solar collectors on the
performances of the solar system.
• The installation of solar collectors either in series or parallel
connection perform at different levels of efficiency.
• We observe how the series and parallel connection of a flat plate
collector set affect the solar system thermal performances and
how they affect also the pressure losses simultaneously.
4. MATHEMATICAL MODELLING OF THE SYSTEM
We consider the following calculations and formulas;
We use MATLAB as the design software
We calculate heat balances;
Heat balance at the transparent cover
Heat balance of the confined air between the absorber and the cover
Heat balance at the absorber plate
Heat balance for the working fluid
Heat balance at the storage tank
Pressure drop calculation
5. PROGRAM DEVELOPMENT
• Based on different differential equations and the heat transfer
coefficients, a MATLAB program is developed, using as input data,
the thermo-physic and geometric properties of the collector
elements, those of the storage tank, the hydraulic geometry and
its configuration in terms of obstacle constituent, characterized by
their specific singular pressure drop coefficients.
• The measured direct normal, horizontal diffuse and global solar
irradiation as well as the ambient temperature and wind speed are
also used.
7. CONT..
• It is observed that the pressure drop in hydraulic circuit of the
collector increases according to a parabolic form. This is linked to
the fact that the linear and single pressure drop equations are
proportional to the square values of the fluid velocity.
• It is observed also that if the fluid temperature increases the total
pressure drop decreases. This is linked to the fact that that
increasing the water temperature leads to decrease in its density
and consequently the pressure drop decreases also.
8. EFFECT OF THE SERIES AND PARALLEL
ARRANGEMENT ON THE SOLAR SYSTEM
PERFORMANCES
1. Mean fluid temperature evolution (parallel
connection)
10. CONT..
• From results presented in the figures above, it is observed that for a
constant storage volume, increasing the collector area leads to increase
in the temperature of the fluid.
• It is observed also that for the same collecting surface where collectors
are connected in series configuration, the outlet fluid temperature from
the panel is higher than that obtained for the case of parallel
configuration.
• In series connection mode, the temperature of solar panel increases and
consequently the heating losses from the system to the surrounding
environment increases and remain higher than that which would be lost
11. HEAT POWER LOSS FROM THE SOLAR
HEATING SYSTEM (PARALLEL CONNECTION)
12. HEAT POWER LOSS FROM THE SOLAR
HEATING SYSTEM (SERIES CONNECTION)
15. CONT..
• The collector temperature increases, the heat
losses power increases and consequently its
instantaneous efficiency decreases as shown in
the above slides.
16. EFFECT OF PARALLEL OR SERIES CONNECTION ON
PRESSURE DROP
1. Pressure drop in the hydraulic circuit of the
solar systems (parallel connection)
17. PRESSURE DROP IN THE HYDRAULIC CIRCUIT
OF THE SOLAR SYSTEMS (SERIES
CONNECTION)
18. CONT..
• From the results presented in figures above it is observed clearly
that increasing the number of collectors leads to increase in the
pressure drop in the hydraulic circuit.
• On the other hand, for the same number of solar collectors it is
observed that pressure drop obtained for the case of 2, 3 and 4
collectors connected in series it is about ten times to that obtained
for the parallel configuration
19. CONCLUSION
• From the obtained results we can conclude that connecting a set of
collectors in series leads to increasing the outlet solar panel fluid
temperature and also leads to decrease the solar collector efficiency and
also increase the pressure drop in the hydraulic circuit of the system
which in turn leads to increase the pump power consumption.
• By contrast connecting collectors in parallel avoids the pressure from
increasing in the hydraulic circuit and avoids decreasing the collector’s
efficiency and the output temperature level through the panel remains
relatively lower. Hence, for solar water heating system choice of the
connecting configuration depends from the user need in term of
temperature level.
• We conclude that the parallel configuration offers a higher efficiency and
