6
H. Tyagi et al.
is recorded using NI DAQ system. The theoretical geometric concentration ratio
predicted is 115 but from the experiment a flux concentration ratio 94 is measured.
Chapter 6: To achieve maximum thermohydraulic performance, by maximizing
the heat transfer and minimizing the pumping power, for a ribbed solar air heater, a
Taguchi method has been used to predict the optimal set of design and flow parameters. An L 16 (4
3 ) orthogonal array is selected as an investigational plan to perform
the computational fluid dynamics (CFD) simulations for investigating the effect of
design parameters, i.e. Reynolds number (4000–16,000), rib pitch to height ratio
(3–12), and rib geometry due to change in inclination angle of front face of the rib
(α = 45°–90°) on the effectiveness of a solar air heater. Nusselt number, friction factor and thermohydraulic performance are considered as performance indexes, and the
minimization of pumping power (minimum pressure drop) and the maximization of
heat transfer and overall performance are taken as the optimization criteria. Results
show that Reynolds number has the greatest influence on the heat transfer as well as
thermohydraulic performance, while rib spacing on the friction factor ratio. The best
combinations of design factors for heat transfer, pressure drop, and thermohydraulic
performance are A 4 B 4 C 1 , A 4 B 1 C 1 , and A 1 B 4 C 1 , respectively. Numerical results validate the aptness of the proposed methodology, so, this investigation suitably offers
an improved rib design for internal fluid flow investigations related to effective heat
transfer applications.
Chapter 7: Solar updraft tower power plant is a way to harness energy from the
sun. It is a simple concept which requires low maintenance and utilises land that
is already being used for growing plants, and generates power from it. A prototype
plant was setup in Manzanares, Spain. Numerical analysis on power generation is
performed for a similar plant assuming it is setup in Ropar. By considering losses via
convection and radiation through the top surface of the collector, collector efficiency
is calculated. Two cases arise here, 1. With 100% collector efficiency and 2. Collector
efficiency is obtained after subtracting convection and radiation losses. The influx of
solar radiation is highest in June. Hence, the variation of parameters like temperature,
velocity, power output, efficiency with time of the day is done by taking averages
for the month of June. Next the impact of physical parameters like chimney height,
chimney radius and collector radius are studied on 21st June 11:00 to 12:00. How
each parameter impacts the output of the plant is studied by creating a mathematical
model of the power plant. Methods to improve the power output are discussed.
Part III of the monograph contain three chapters which discuss the possibilities
of space cooling using non-conventional sources of energy, such as solar thermal
powered adsorption cooling. The abstracts of each of these three chapters are as
follows.
Chapter 8: Adsorption based cooling systems are gaining considerable attention
since it can utilize low grade thermal energy, which otherwise could go as a waste.
Heat sources possessing a temperature of as low as 60 °C can drive an adsorption
chiller and that temperature requirement is even lower in the case of multi-stage
adsorption cooling systems. A typical flat plate solar collector can provide hot water
having a temperature of 65 °C in most of the countries in the Asian region. The temperature of evacuated tube collectors’ water outlet can reach above 95 °C. In order
H. Tyagi et al.
is recorded using NI DAQ system. The theoretical geometric concentration ratio
predicted is 115 but from the experiment a flux concentration ratio 94 is measured.
Chapter 6: To achieve maximum thermohydraulic performance, by maximizing
the heat transfer and minimizing the pumping power, for a ribbed solar air heater, a
Taguchi method has been used to predict the optimal set of design and flow parameters. An L 16 (4
3 ) orthogonal array is selected as an investigational plan to perform
the computational fluid dynamics (CFD) simulations for investigating the effect of
design parameters, i.e. Reynolds number (4000–16,000), rib pitch to height ratio
(3–12), and rib geometry due to change in inclination angle of front face of the rib
(α = 45°–90°) on the effectiveness of a solar air heater. Nusselt number, friction factor and thermohydraulic performance are considered as performance indexes, and the
minimization of pumping power (minimum pressure drop) and the maximization of
heat transfer and overall performance are taken as the optimization criteria. Results
show that Reynolds number has the greatest influence on the heat transfer as well as
thermohydraulic performance, while rib spacing on the friction factor ratio. The best
combinations of design factors for heat transfer, pressure drop, and thermohydraulic
performance are A 4 B 4 C 1 , A 4 B 1 C 1 , and A 1 B 4 C 1 , respectively. Numerical results validate the aptness of the proposed methodology, so, this investigation suitably offers
an improved rib design for internal fluid flow investigations related to effective heat
transfer applications.
Chapter 7: Solar updraft tower power plant is a way to harness energy from the
sun. It is a simple concept which requires low maintenance and utilises land that
is already being used for growing plants, and generates power from it. A prototype
plant was setup in Manzanares, Spain. Numerical analysis on power generation is
performed for a similar plant assuming it is setup in Ropar. By considering losses via
convection and radiation through the top surface of the collector, collector efficiency
is calculated. Two cases arise here, 1. With 100% collector efficiency and 2. Collector
efficiency is obtained after subtracting convection and radiation losses. The influx of
solar radiation is highest in June. Hence, the variation of parameters like temperature,
velocity, power output, efficiency with time of the day is done by taking averages
for the month of June. Next the impact of physical parameters like chimney height,
chimney radius and collector radius are studied on 21st June 11:00 to 12:00. How
each parameter impacts the output of the plant is studied by creating a mathematical
model of the power plant. Methods to improve the power output are discussed.
Part III of the monograph contain three chapters which discuss the possibilities
of space cooling using non-conventional sources of energy, such as solar thermal
powered adsorption cooling. The abstracts of each of these three chapters are as
follows.
Chapter 8: Adsorption based cooling systems are gaining considerable attention
since it can utilize low grade thermal energy, which otherwise could go as a waste.
Heat sources possessing a temperature of as low as 60 °C can drive an adsorption
chiller and that temperature requirement is even lower in the case of multi-stage
adsorption cooling systems. A typical flat plate solar collector can provide hot water
having a temperature of 65 °C in most of the countries in the Asian region. The temperature of evacuated tube collectors’ water outlet can reach above 95 °C. In order