5 Design and Development of a Concentrated Solar …
63
and showed an efficiency of 64.25%. Some of the involved process parameters are
summarized in Table 5.1. Currently flat-plate solar water heater systems are widely
utilized. However, flat plate collectors suffer from disadvantages like occupying
more roof area and are corrosion prone. This has led to design and development of
concentrated solar heating systems.
In concentrated solar water heating systems, compound parabolic concentrators
(CPCs) are one of the majorly used collectors for domestic water heating purposes
after conventional flat plate collectors. Hadjiat et al. (2018) proposed design and
analysis of a novel integrated collector storage (ICS) solar water heater. The system
consists of CPC reflectors where solar collector and water storage are integrated as
single unit with the geometric concentration ratio of collector being around 1.22
and the highest temperature of water in tank is around 50
◦ C. Benrejeb et al. (2015)
proposed an ICS solar water heater system with improved optical and thermal efficiencies. The geometric concentration ratio was improved from 1.05 in old design
to 1.34 in new design and the highest temperature attained was 65
◦ C. Harmim et al.
(2019) proposed a design of ICS solar water heater for integration into building facade. A linear parabolic reflector was used as concentrator, with the maximum water
temperature obtained varying from 40 to 49
◦ Cand the geometric concentration ratio
reported is 3.3. Chong et al. (2012) investigated solar water heater using stationary
V-trough collector. The geometry is simpler as compared to that of a CPC. The set up
was designed for solar concentration ratio of 1.8 suns whereas from the experiments
it achieved a concentration ratio of 1.41 suns and the highest water temperature attained in the tank is 85.9
◦ C. Rajamohan et al. (2017) carried out analysis on a solar
water heater with parabolic dish concentrator and a conical absorber. Water is the
working fluid, and as solar radiation is concentrated onto the absorber the water in
the absorber evaporates and converts into vapor phase. The vapor is passed into a
heat exchanger where heat transfer between vapor and fresh cold water occurs with
the vapor condensing to liquid phase. The working fluid returns to the bottom of the
conical absorber under gravity and continues as a cyclic process inside the system.
The highest water temperature achieved is 65
◦ C and the average system efficiency
achieved is 55.40%. The available literature in concentrated solar water system is not
abundant. Further, design of simple systems which can be easily fabricated and can
produce a high concentration ratio is desirable. In this work, a concept of concentrating solar water heating (CSWH) system is proposed and evaluated. This system
is expected to be versatile with multifaceted applications such as:
• Reduce the rate of heat loss by means of reducing the surface area while keeping
the water temperature comparable to conventional systems. This is expected to
increase the overall system efficiency.
• The proposed CSWH system envisages a flux concentration of about 100 Suns.
This may allow in future evaluation of other heat transfer fluids like oil by elevating
the operating temperature.
• The reduction of receiver area may allow implementation of such a system in cold
deserts or high-altitude by mitigating the freezing related issues.
63
and showed an efficiency of 64.25%. Some of the involved process parameters are
summarized in Table 5.1. Currently flat-plate solar water heater systems are widely
utilized. However, flat plate collectors suffer from disadvantages like occupying
more roof area and are corrosion prone. This has led to design and development of
concentrated solar heating systems.
In concentrated solar water heating systems, compound parabolic concentrators
(CPCs) are one of the majorly used collectors for domestic water heating purposes
after conventional flat plate collectors. Hadjiat et al. (2018) proposed design and
analysis of a novel integrated collector storage (ICS) solar water heater. The system
consists of CPC reflectors where solar collector and water storage are integrated as
single unit with the geometric concentration ratio of collector being around 1.22
and the highest temperature of water in tank is around 50
◦ C. Benrejeb et al. (2015)
proposed an ICS solar water heater system with improved optical and thermal efficiencies. The geometric concentration ratio was improved from 1.05 in old design
to 1.34 in new design and the highest temperature attained was 65
◦ C. Harmim et al.
(2019) proposed a design of ICS solar water heater for integration into building facade. A linear parabolic reflector was used as concentrator, with the maximum water
temperature obtained varying from 40 to 49
◦ Cand the geometric concentration ratio
reported is 3.3. Chong et al. (2012) investigated solar water heater using stationary
V-trough collector. The geometry is simpler as compared to that of a CPC. The set up
was designed for solar concentration ratio of 1.8 suns whereas from the experiments
it achieved a concentration ratio of 1.41 suns and the highest water temperature attained in the tank is 85.9
◦ C. Rajamohan et al. (2017) carried out analysis on a solar
water heater with parabolic dish concentrator and a conical absorber. Water is the
working fluid, and as solar radiation is concentrated onto the absorber the water in
the absorber evaporates and converts into vapor phase. The vapor is passed into a
heat exchanger where heat transfer between vapor and fresh cold water occurs with
the vapor condensing to liquid phase. The working fluid returns to the bottom of the
conical absorber under gravity and continues as a cyclic process inside the system.
The highest water temperature achieved is 65
◦ C and the average system efficiency
achieved is 55.40%. The available literature in concentrated solar water system is not
abundant. Further, design of simple systems which can be easily fabricated and can
produce a high concentration ratio is desirable. In this work, a concept of concentrating solar water heating (CSWH) system is proposed and evaluated. This system
is expected to be versatile with multifaceted applications such as:
• Reduce the rate of heat loss by means of reducing the surface area while keeping
the water temperature comparable to conventional systems. This is expected to
increase the overall system efficiency.
• The proposed CSWH system envisages a flux concentration of about 100 Suns.
This may allow in future evaluation of other heat transfer fluids like oil by elevating
the operating temperature.
• The reduction of receiver area may allow implementation of such a system in cold
deserts or high-altitude by mitigating the freezing related issues.