scholarly journals Sizing Methodology of a Multi-Mirror Solar Concentrated Hybrid PV/Thermal System

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3276 ◽  
Author(s):  
Mohamed Gomaa ◽  
Ramadan Mustafa ◽  
Hegazy Rezk ◽  
Mujahed Al-Dhaifallah ◽  
A. Al-Salaymeh
Keyword(s):  
Thermal Efficiency ◽  
Concentration Ratio ◽  
Cooling System ◽  
Flat Glass ◽  
Cooling Water ◽  
Coolant Fluid ◽  
Inlet Temperature ◽  
Cooling Water Temperature ◽  
Inclination Angles ◽  
Linear Fresnel Reflector

The use of a concentrated photovoltaic (CPV) system significantly reduces the required solar cell area that often accounts for the major cost of a PV solar system. A comprehensive performance analysis of a multi-mirror solar concentrated hybrid PV thermal (CPVT) system was conducted. Among different concentrating systems, Linear Fresnel Reflector (LFR) systems are more effective due to their simplicity of operation and low fabrication cost. A mathematical model and the simulation of a CPVT system employing a linear configuration and horizontal absorber is developed here in order to evaluate its performance parameters, using a FORTRAN programing technique. The concentrator system consists of, different width of flat glass mirrors placed under various inclination angles, focusing sunlight on to the PV solar cells mounted along the active cooling system. The effect of focus distance on concentration ratio, collector width, and heat gained by the coolant fluid are investigated. All parameters of the linear Fresnel reflector solar concentrator system are determined and the effect of cooling mass flow rate and cooling inlet temperature upon the system performance is evaluated. With regards to simulation results obtained via the focus distances, the width of mirrors decreased by increasing the number of mirrors, and in turn by increasing the focus distances, this resulted in an increase in CR values. For the specific number of mirrors, concentration ratio increased simultaneously increasing the focus distance; furthermore, increasing the number of mirrors resulted in a reduction in both the width of the mirrors and their inclination angles, and an increase in CR values. The results further confirmed that the total (combined electrical-thermal) efficiency is higher than that of the individual electrical as well as thermal efficiency; reaching approximately 80% and showed no sensitivity to the rises in cooling water temperature for temperature cases under consideration.

An Analytical Model to Simulate the Automotive Cooling System

2005 ◽  
Author(s):  
Emad Samadiani ◽  
Amirhasan Kakaee
Keyword(s):  
Analytical Model ◽  
Cooling System ◽  
Water Flow Rate ◽  
Wind Tunnel Test ◽  
Cooling Water ◽  
Inlet Temperature ◽  
Automotive Engine ◽  
Cooling Water Temperature ◽  
Cooling Water Flow Rate ◽  
Flat Tubes

In this paper the effect of simultaneous operation of the automotive radiator, fan, engine, and cooler system on radiator coolant inlet temperature is studied. For this purpose, an analytical model is developed to simulate the automotive cooling system. First, the heat transfer rate and air pressure drop in radiators with louvered corrugated fins and flat tubes are modeled and compared with wind tunnel test results over six radiator cores. Also, the air flow path is simulated. Two preexisting codes are used to simulate the automotive engine and cooler system. Then a code is developed in order to investigate the effect of different parameters related to each component of the cooling system on cooling water inlet temperature. In the end, the effect of ambient temperature, cooling water flow rate, and fin pitch on cooling water temperature at different speeds of a sample automobile is examined.

scholarly journals The Impact of Coolant Temperatures on Various Cycle Parameters of NH3-H2O Absorption Chiller from Solar Source

2021 ◽  
pp. 43-50
Author(s):  
Adel Akair ◽  
Hesham Baej
Keyword(s):  
Water Temperature ◽  
Temperature Increase ◽  
Cooling Water ◽  
Relative Difference ◽  
Inlet Temperature ◽  
Absorption Chiller ◽  
Ammonia Water ◽  
Solar Source ◽  
Cooling Water Temperature ◽  
The Difference

The cycles’ structure was based on recently published technical information of low-temperatures powered Ammonia-water (NH3-H2O) absorption chiller.  The cycle was completely modeled using different components available within the refrigeration library of IPSEpro software package.  Using the model a cold-water ammonia-water absorption chiller was examined and validated in accordance to the relevant thermodynamic laws and charts. A low-grade temperature solar resource was modeled to energise the proposed model. For water-cooled cycles, the rejected heat from the absorbers and the condensers was carried out by water, at an average fixed temperature of 25°C, pumped out from ground water. The results obtained show that when the Coefficient of performance (COP), heat inputs into the generator, and cooling mass flow rates are fixed, the cycle parameters are highly affected by variation of coolant temperature. For instance when cooling water temperature decreases. Also when cooling water temperature increase, the cycle pressure, usable chilled water temperature difference and desorber outlet temperature increase whereas mass concentration and refrigeration capacity decrease. The effectiveness of the generator inlet temperature (solar source) is a factor of the largest effect to the COP. The difference was 0.1401, 27.4%. The chilled water inlet temperature (underground water) is the second largest effect to the COP. The difference between the maximum and the minimum value is 0.0865 and the relative difference is 18.9% with cooling capacity 12 kW. The influence of evaporator temperature to the COP is also minimal with only 2.2% difference. The influence of absorber temperature and condenser temperature to the COP are almost identical, the relative difference is 19.2% and 18.9% respectively.

Research and Application of the Auto-Control Cooling System for the Diesel Engine

2013 ◽  
Vol 805-806 ◽  
pp. 1970-1974
Author(s):  
Hong Lei Pang ◽  
Cai Yun Zhu ◽  
Zhi Bin Ni ◽  
Yao Hua Wei
Keyword(s):  
Diesel Engine ◽  
Water Temperature ◽  
Cooling System ◽  
Cooling Water ◽  
Coolant Temperature ◽  
Saving Rate ◽  
Fuel Saving ◽  
Single Chip ◽  
Cooling Water Temperature ◽  
Operation Conditions

In order to solve the problem that the traditional cooling system cannot adjust the cooling water temperature to the different operation conditions of diesel engine, the auto-control cooling system is designed. Using it, the coolant temperature can be adjusted automatically by the single-chip which controls the transducer-controlled pump and the electronic dividing valve which replaces the thermostat. We use the thermal equilibrium bench to verify the figures, and the result is show that using the exhaust of generator heats the cooling water can shorten 13 minutes in starting process and the cooling water temperature adjusted automatically to the changing operation conditions of iesel can decrease the fuel consumption remarkably, the highest fuel saving rate reached 5.4%, the averagely fuel saving rate reached 3.6%.

scholarly journals Energy and exergy estimation for a combined cycle of solid CO2 production and NH3-H2O single effect absorption chiller

2016 ◽  
Vol 19 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Phu Minh Nguyen
Keyword(s):  
Cooling System ◽  
Cooling Water ◽  
Combined Cycle ◽  
Co2 Production ◽  
Absorption Chiller ◽  
Cooling Water Temperature ◽  
Cycle Simulation ◽  
Energy And Exergy ◽  
Single Effect ◽  
Exergy Analyses

In order to reduce the compression power, to use an integrated thermal-driven cycle, and to mitigate the CO2 content in the air, a new combined cycle of absorption chiller and vaporcompression refrigeration cycle to produce carbon dioxide dry ice was devised and analyzed. In this study, the energy and the exergy analyses of the combined cycle were presented. The combined cycle simulation was carried out by using EES (Engineering Equation Solver) program. The CO2 condensation pressure and the generator temperature were considered as key parameters. Results show that the total compression and pumping power using the present combined cycle can be reduced remarkably, amounting to 44.4 %, in comparison with that in the conventional ammonia cooling system. Most of the irreversibility occur in the absorption system and the irreversibility of the absorber has the largest portion. The temperature reduction of the solution or increase in the cooling water temperature can improve the irreversibility of the absorber. However, the latter decreases the irreversibility more than the former.

Effect of nanofluids on heat transfer and cooling system of the photovoltaic/thermal performance

2019 ◽  
Vol 29 (6) ◽  
pp. 1920-1946 ◽  
Author(s):  
Rehena Nasrin ◽  
Md. Hasanuzzaman ◽  
N.A. Rahim
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Volume Fraction ◽  
Cooling System ◽  
Solid Volume Fraction ◽  
Inlet Temperature ◽  
Content Type ◽  
Water Based

PurposeEffective cooling is one of the challenges for photovoltaic thermal (PVT) systems to maintain the PV operating temperature. One of the best ways to enhance rate of heat transfer of the PVT system is using advanced working fluids such as nanofluids. The purpose of this research is to develop a numerical model for designing different form of thermal collector systems with different materials. It is concluded that PVT system operated by nanofluid is more effective than water-based PVT system.Design/methodology/approachIn this research, a three-dimensional numerical model of PVT with new baffle-based thermal collector system has been developed and solved using finite element method-based COMSOL Multyphysics software. Water-based different nanofluids (Ag, Cu, Al, etc.), various solid volume fractions up to 3 per cent and variation of inlet temperature (20-40°C) have been applied to obtain high thermal efficiency of this system.FindingsThe numerical results show that increasing solid volume fraction increases the thermal performance of PVT system operated by nanofluids, and optimum solid concentration is 2 per cent. The thermal efficiency is enhanced approximately by 7.49, 7.08 and 4.97 per cent for PVT system operated by water/Ag, water/Cu and water/Al nanofluids, respectively, compared to water. The extracted thermal energy from the PVT system decreases by 53.13, 52.69, 42.37 and 38.99 W for water, water/Al, water/Cu and water/Ag nanofluids, respectively, due to each 1°C increase in inlet temperature. The heat transfer rate from heat exchanger to cooling fluid enhances by about 18.43, 27.45 and 31.37 per cent for the PVT system operated by water/Al, water/Cu, water/Ag, respectively, compared to water.Originality/valueThis study is original and is not being considered for publication elsewhere. This is also not currently under review with any other journal.

Experimental Study on Steam Condensation in Horizontal Microchannels

2009 ◽  
Author(s):  
Xuehu Ma ◽  
Xiaoguang Fan ◽  
Zhong Lan ◽  
Tingting Hao ◽  
Tianyi Song
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Glass Plate ◽  
Cooling Water ◽  
Pyrex Glass ◽  
Inlet Temperature ◽  
Steam Condensation ◽  
Steam Quality ◽  
Cooling Water Temperature ◽  
Trapezoidal Microchannel

Experiment was conducted to study steam condensation in horizontal microchannel etched on silicon wafer and bonded by a Pyrex glass plate from the top. The trapezoidal microchannel had a top width of 7943.11μm and depth of 81.77μm with hydraulic diameter of 161.49μm. The experiments were performed at different steam mass fluxes ranged from 128 kg m−2 s−1 to 320 kg m−2 s−1, while the inlet temperature of cooling water was fixed at 30°C or 50°C. Characteristics of condensation heat transfer and pressure drop in microchannels were measured and discussed. The temperature of Pyrex glass and local steam quality were also tested. It is found that the heat transfer flux, heat transfer coefficient and pressure drop depend greatly on steam mass flux and cooling water temperature.

Performance Study of Activated Carbon – Hydrofluoro Olefin Based Adsorption Cooling System

2013 ◽  
Vol 465-466 ◽  
pp. 206-210
Author(s):  
Khairul Habib
Keyword(s):  
Activated Carbon ◽  
Waste Heat ◽  
Cooling System ◽  
Combustion Engine ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Performance Study ◽  
Adsorption Chiller

In this study, a dynamic behavior of a two bed adsorption chiller has been analyzed using highly porous activated carbon of type Maxsorb III as adsorbent and hydrofluoro olefin [R1234ze (E)] as refrigerant. R1234ze (E) has a low global warming potential (GWP) and zero ozone depletion potential (ODP). A parametric study has been presented where the effects of adsorption/desorption cycle time, cooling water inlet temperature and regeneration temperature on the performance are reported in terms of cooling capacity and coefficient of performance (COP). This chiller can be driven by the waste heat of internal combustion engine and hence it is applicable in automobile air conditioning.

Analysis of a Solar Space Cooling System Using Liquid Desiccants

1990 ◽  
Vol 112 (4) ◽  
pp. 246-250 ◽  
Author(s):  
P. Gandhidasan
Keyword(s):  
Heat Exchanger ◽  
Cooling System ◽  
Cooling Water ◽  
Ambient Air ◽  
Solution Concentration ◽  
Simple Expression ◽  
Ventilation Mode ◽  
Cooling Water Temperature ◽  
System A ◽  
Space Cooling

For tropical countries, solar space cooling is an attractive proposition. Dehumidification of air in hot, humid climates is almost as important as cooling. Removal of moisture from the air is much easier to achieve than cooling the air. The proposed cooling system operates on the ventilation mode. The ambient air is dehumidified using liquid desiccants followed by adiabatic evaporative cooling. The desiccant soon becomes saturated with the water extracted from the air and can be regenerated by using solar energy. For this system, a simple expression is derived in this paper to predict the amount of heat removed from the space to be conditioned in terms of known initial parameters through a simplified vapor pressure correlation and effectiveness of the dehumidifier and the heat exchanger. The effect of ambient air conditions, solution concentration, the cooling water temperature and the effectiveness of the dehumidifier and the heat exchanger on the performance of the cooling system are also discussed in this paper.

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