1 Introduction to Solar Energy …
5
consumption in buildings is maintaining thermal comfort. Providing a thermally
comfortable environment with an energy efficient design will not only lead to energy
and cost savings, but will also have other intangible benefits, such as enhanced
productivity, and health and well-being of the occupants. Studies have reported that
buildings have 50–60% energy saving potential by means of an efficient design. This
study aims at utilizing passive design strategies, such as provision of insulation and
window glazing, to analyse their effects on thermal comfort of the occupants inside an
office room. Measurements of indoor environmental quality parameters was done for
the room, and Predicted Mean Vote and Percentage People Dissatisfied models, given
in ASHRAE Standard 55, have been used in this study to assess the existing comfort
levels of the occupants. A parametric study to examine their influence on the thermal
environment using these models has been done using IDA ICE Beta 4.7 software.
It was observed that application of the passive techniques although enhanced the
thermal environment of the room, the comfort levels were still not within the ideal
range specified by ASHRAE. The study concluded that more passive strategies can
be employed to enhance the comfort levels. This would help in reducing the need for
alternate methods of space conditioning, hence, leading to energy conservation.
The next part in this monograph, (Part II) consists of three chapters which deal
with the heating aspects of solar thermal systems. It contains chapters which study
the solar water heating system as well as solar air heaters. Moreover it contains
a chapter highlighting the mathematical model of a solar updraft tower where a
buoyancy driven-flow (heated by solar energy) drives turbine for power generation.
The abstracts of each of these three chapters are as follows.
Chapter 5: Solar energy is a promising renewable source to support the growing energy demand. This energy is widely harnessed for solar water heating systems to provide hot water for both domestic and industrial sectors thus reducing
use of conventional energy sources. In this work, a concentrated solar water heater
(CSWH) system is designed and fabricated at IIT Jodhpur. The main objectives are
development of a point focus based direct solar water heating system and preliminary experiment based evaluation of the designed system. The system envisages a
flux concentration of 100 Suns, which will enable receiver area reduction and the
use of other heat transfer fluids like oil in future. The CSWH system consists of
(a) receiver and (b) parabolic dish with two-axis sun tracking provision. In the conventional solar water heater system the irradiance from sun is directly collected by
the collector whereas in concentrated solar water heater the reflected irradiance is
received by the receiver. The reflector consists of a reflecting surface mounted on a
parabolic structure and the cavity receiver consists of consists of a serpentine copper
tube exposed to concentrated irradiance. The receiver will be insulated from top in
order to prevent heat loss from one of its surface. An optical model of parabolic
dish and receiver has been developed using TracePro software. This model is used as
reference to generate the flux density distribution. The experimental setup consists of
a parabolic dish, a receiver with thermocouples, a Coriolis flow meter, pump, water
tank and NI DAQ. Coriolis flow meter is used to measure the mass flow rate in the
system. K-type thermocouples are attached on to the receiver and the temperature
5
consumption in buildings is maintaining thermal comfort. Providing a thermally
comfortable environment with an energy efficient design will not only lead to energy
and cost savings, but will also have other intangible benefits, such as enhanced
productivity, and health and well-being of the occupants. Studies have reported that
buildings have 50–60% energy saving potential by means of an efficient design. This
study aims at utilizing passive design strategies, such as provision of insulation and
window glazing, to analyse their effects on thermal comfort of the occupants inside an
office room. Measurements of indoor environmental quality parameters was done for
the room, and Predicted Mean Vote and Percentage People Dissatisfied models, given
in ASHRAE Standard 55, have been used in this study to assess the existing comfort
levels of the occupants. A parametric study to examine their influence on the thermal
environment using these models has been done using IDA ICE Beta 4.7 software.
It was observed that application of the passive techniques although enhanced the
thermal environment of the room, the comfort levels were still not within the ideal
range specified by ASHRAE. The study concluded that more passive strategies can
be employed to enhance the comfort levels. This would help in reducing the need for
alternate methods of space conditioning, hence, leading to energy conservation.
The next part in this monograph, (Part II) consists of three chapters which deal
with the heating aspects of solar thermal systems. It contains chapters which study
the solar water heating system as well as solar air heaters. Moreover it contains
a chapter highlighting the mathematical model of a solar updraft tower where a
buoyancy driven-flow (heated by solar energy) drives turbine for power generation.
The abstracts of each of these three chapters are as follows.
Chapter 5: Solar energy is a promising renewable source to support the growing energy demand. This energy is widely harnessed for solar water heating systems to provide hot water for both domestic and industrial sectors thus reducing
use of conventional energy sources. In this work, a concentrated solar water heater
(CSWH) system is designed and fabricated at IIT Jodhpur. The main objectives are
development of a point focus based direct solar water heating system and preliminary experiment based evaluation of the designed system. The system envisages a
flux concentration of 100 Suns, which will enable receiver area reduction and the
use of other heat transfer fluids like oil in future. The CSWH system consists of
(a) receiver and (b) parabolic dish with two-axis sun tracking provision. In the conventional solar water heater system the irradiance from sun is directly collected by
the collector whereas in concentrated solar water heater the reflected irradiance is
received by the receiver. The reflector consists of a reflecting surface mounted on a
parabolic structure and the cavity receiver consists of consists of a serpentine copper
tube exposed to concentrated irradiance. The receiver will be insulated from top in
order to prevent heat loss from one of its surface. An optical model of parabolic
dish and receiver has been developed using TracePro software. This model is used as
reference to generate the flux density distribution. The experimental setup consists of
a parabolic dish, a receiver with thermocouples, a Coriolis flow meter, pump, water
tank and NI DAQ. Coriolis flow meter is used to measure the mass flow rate in the
system. K-type thermocouples are attached on to the receiver and the temperature