scholarly journals Performance Of P1 Model In The Prediction Of Static Temperature And Velocity Magnitude Of Therminol D-12 In An Evacuated Tube Solar Collector

2019 ◽  
Vol 8 (11) ◽  
pp. 255-261
Keyword(s):  
Solar Radiation ◽  
Winter Season ◽  
Heat Fluxes ◽  
Hot Water ◽  
Experimental Result ◽  
Water Heaters ◽  
Velocity Magnitude ◽  
D 12 ◽  
Flat Plate Collector ◽  
Evacuated Tube

Instant hot water requirement is more in tropical countries during the winter season. The conventional flat plate collector and evacuated tube collector based solar water heaters are unable to delivesr instant hot water in the presence of low solar radiation. Passive heating of water in an evacuated tube with heat transfer fluids having low specific heat can deliver a better solution to the above problem. Therminol D-12 was identified as one such fluid and its performance was studied under varying flow rates and radiation heat fluxes. The analysis was carried out with the CFD solver FLUENT 6.2. P1 radiation model was used to predict the static temperature and velocity magnitude of therminol D-12 at the exit of the evacuated tube. The result obtained from the CFD analysis was validated with the experimental result. The deviation of experimental result from the predicted result was found to be less than 5%. The error percentage increases with increasing radiative heat fluxes due to convection boundary conditions. The performance of P1 model was found to be good for solar radiation experiments less than 600 W/m2 .

scholarly journals Hybrid system solar collectors - heat pumps for domestic water heating

2019 ◽  
Vol 23 (6 Part A) ◽  
pp. 3675-3685
Author(s):  
Simon Marcic ◽  
Rebeka Kovacic-Lukman ◽  
Peter Virtic
Keyword(s):  
Solar Radiation ◽  
Flat Plate ◽  
Heat Pump ◽  
Autonomous System ◽  
Identical Condition ◽  
Heat Pumps ◽  
Hot Water ◽  
Water Heating ◽  
Domestic Water ◽  
Flat Plate Collector

This paper deals with the use of solar energy, heat pumps, and solar system-heat pump combinations for domestic water heating. The testing of solar tiles, flat plate collectors as an autonomous system, as well as flat plate collector-heat pump and solar tile-heat pump combinations, are presented. Black-coloured water absorbs solar radiation flows through solar tiles made of transparent polymethyl methacrylate (CH2C(CH3)COOCH3). At the same time, solar tiles are used as a roof covering and as a solar radiation collector. Hot water from solar tiles or a flat plate collector is directed to the heat pump, which increases the temperature of water entering the boiler heating coil. The heat of water heated in solar tiles or in flat plate collectors serves as a source of energy for the heat pump. Since the goal was realistically evaluate the efficiency of solar tiles in comparison with the flat plate collector, extensive measurements of both systems under identical condition were carried out. The experiments were carried out in rainy, cloudy, and clear weather.

Combined Convective-Radiative Thermal Analysis of a Solar Flat-Plate Collector

2015 ◽  
Author(s):  
Aaron P. Eicoff ◽  
Mohammad H. Naraghi
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Fluxes ◽  
Heat Transfer Analysis ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Flat Plate Solar Collector ◽  
Flat Plate Collector ◽  
Solar Water Heaters

A model for the combined spectral radiative, conductive and convective heat transfer analysis of solar water heaters is presented. The radiation aspect of this model is based on the spectral distribution of the solar irradiance and spectrally selective properties of the system components. The convective equations that were used are based on well-established empirical models. The heat transfer characteristics of the solar water heater are determined by simultaneously solving a nonlinear system of energy balance equations for the various physical components using an iterative approach. The model is used to predict temperatures and heat fluxes for a typical flat-plate solar collector for various geometries and conditions i.e. flow rates, solar irradiances and spectral properties.

scholarly journals Experimental Study of Concentrated Solar Power on Heat Feed Water Heaters in Steam Power Plants in Iraq

2021 ◽  
Vol 11 (1) ◽  
pp. 137-152
Author(s):  
Dr. Dhamyaa Saad Khudor ◽  
Dr. Ghanim Kadhim Abdulsada ◽  
Moumin Mahdi Issa
Keyword(s):  
Solar Radiation ◽  
Power Plants ◽  
Hot Water ◽  
Feed Water ◽  
Outlet Temperature ◽  
Concentrated Solar Power ◽  
Water Heater ◽  
Steam Power ◽  
Water Heaters ◽  
Steam Power Plants

For generating power, solar energy is counted a good exporter. Iraq is located in a hot zonewith latitude from 32 degree N to 36 degree N. In Iraq, the average solar radiation is about 7kilowatt hours / day.In this work, central receiving tower was used to obtain steam using the available solar energyin summer and winter. To heat the feed water heater of South Baghdad Electrical Steam PowerPlant, steam utilization for this purpose. In the project, manufacturing the central receivertower, which is consisting of 150 mirrors fixed upon 75 manual tracking heliostats arranged forutilization the solar radiation concentrated on the central receiving tank (CRT). Pipes systemswere used for hot water or steam exits from receiver. In this study, the central receiver tank(0.5m*1m) was filled with 157 liter of water. The experimental work was run for one yearfrom June 2015 – May 2016. The outlet temperature of water from central tower receiver wassteam for (July and August 2015) and hot water with high temperature for other months of theyear. The results obtained from our system, solar shares for heating the feed water heater ofSouth Baghdad Electrical Steam Power Plant up to 1.86 % and an annual average of 1.03%.Temperature, power concentration factor and system efficient are greatly influenced by thenumber of heliostats used. A sample of calculations is used to evaluate the mathematical dataof hot water and steam temperatures obtained from this study. These values are approximatewith experimental data when compared together.

scholarly journals Decoupling the Monitoring of Solar Water Heaters and their Usage Profiles

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3186
Author(s):  
Julian C. Nwodo ◽  
Ochuko K. Overen ◽  
Edson L. Meyer
Keyword(s):  
Low Cost ◽  
Hot Water ◽  
Housing Sector ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Water Heaters ◽  
Low Cost Housing ◽  
Solar Water Heaters ◽  
Evacuated Tube

South Africa is the most technologically advanced nation in Africa. However, the country is plagued with constant load shedding. The country receives about 2500 sunshine hours annually, with daily average irradiation levels of 4.5–6.5 kWh/m2. Despite these potentials, the use of electricity for domestic water heating is still prevalent in the country. The mass rollout of solar water heating (SWH) technologies in the low-cost housing sector across the country were met with massive failures. This study aims to assess the energy yield of a passive flat plate and an evacuated tube solar water heating system by evaluating the performance of these systems to address the energy crisis in South Africa. The flat plate (FP) and evacuated tube (ET) solar water heating systems were monitored for four days, characterised by varying sky conditions through instantaneous data measurement at 5 s. The parameters measured were water temperature, ambient temperature, irradiance at the plane of array, relative humidity, wind speed and direction. The results obtained show that a maximum irradiance of 1050 W/m2 was obtained on a clear day and corresponded to a hot water temperature of about 58 °C and 65 °C for the FP and ET, respectively. However, a cloudy day with a maximum irradiance of 400 W/m2 produced about 22 °C and 29 °C of hot water for the FP and ET, respectively. The results obtained in this study will guide stakeholders in the renewable energy sector towards employing SWH systems to replace or augment the electric geyser. Solar water heaters (SWH) can be used in the low-cost housing sector to provide hot water. Hence, the assessments in this study offer essential information for the deployment of these systems to reduce demand on the ailing South African electricity utility, Eskom, and mitigate climate change.

Three Dimensional CFD Simulation of Thermosyphon Flow in an Unglazed Solar Flat Plate Collector

2013 ◽  
Author(s):  
Yagnesh N. Sharma ◽  
Manjunath M. Shivamallaiah ◽  
Vasudeva K. Karanth
Keyword(s):  
Flat Plate ◽  
Thermal Performance ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Operating Conditions ◽  
Thermal Design ◽  
Hot Water ◽  
Flat Plate Collector ◽  
Solar Heat Flux

Thermosyphon unglazed solar flat plate collectors have been widely used all over the world to harness solar energy for generating hot water for various applications. This is mainly due to the passive nature of the system besides being simple in design. However, flat plate collectors are associated with higher heat losses from the surface leading to lower thermal performance. Hence, there is a dire need to optimize the thermal design aspects of the flat plate collector in order to achieve higher thermal performance. In this paper, the results of a full three dimensional CFD simulation of thermosyphon flow in an unglazed solar flat plate collector are presented. It is observed from the parametric study that there are interesting trends for the temperature distribution of the absorber plate and loop water for various simulated solar heat flux inputs. This analysis also brings out the effect of various simulated heat fluxes on the mass flow rates in the collector loop. The results of this CFD simulation study provide an insight into the behavior of the thermosyphon solar flat plate collector under various operating conditions and hence will be further helpful to undertake optimization for enhanced thermal performance of the collector.

scholarly journals Thermal Performance of Solar Hot Water Systems Using a Flat Plate Collector of Accelerated Risers

2012 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
KE Amori ◽  
NS Jabouri
Keyword(s):  
Tilt Angle ◽  
Water System ◽  
Water Systems ◽  
Hot Water ◽  
The Other ◽  
Sectional Area ◽  
Cross Sectional ◽  
Water Heaters ◽  
Flat Plate Collector ◽  
Solar Water Heaters

 This study focuses on a comparison of the performance of two similar locally-fabricated solar water heaters. One of the collectors features a new design for accelerated absorber; its risers are made of converging ducts whose exit area is half that of the entrance. The other collector is a conventional absorber, with risers of the same cross sectional area along its length. Each collector is the primary part of an indirect thermosyphon circulation solar hot water system. Both collectors face south with a fixed tilt angle of 33.3

Temperature Evolution of Evacuated Tube Adsorbtion Bed Heated by Solar Radiation

2014 ◽  
Author(s):  
Chun-Xu Du ◽  
Zhong-Xian Yuan ◽  
Xiao-Huang Hou ◽  
Feng Xin ◽  
Dong-Dong Gao ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Temperature Evolution ◽  
Evacuated Tube
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