Study on Collector Efficiency of Flat-Plate-Type Evacuated Solar Collector to Get Hot Water Near 100°C

2010 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Tsuyoshi Kawanami
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Solar Collector ◽  
Storage Tank ◽  
Heat Storage ◽  
Hot Water ◽  
Measured Temperature ◽  
Control Methods ◽  
Collector System ◽  
Collector Efficiency

We studied effects of parameters on collector efficiency of evacuated solar collector system to get hot water near 100°C. Change of temperature in the solar collector system is calculated for a daily change of solar radiation with 5 minutes cloud. Six operation-control methods are examined. Calculation results show that the effect of the control methods on average collector efficiency for one day is small as 1%. Best control method to minimize effect of the cloud on exit temperature fluctuation of the water is that the flow rate of the water is controlled proportional to the solar radiation. Two types of heat storage system are examined: a non-circulating type (supply new water and accumulate heated water in the heat storage tank) and a circulating type (circulating water from the heat storage tank). The non-circulating type is effective to use the solar energy in the daytime, and the circulating type is effective to use solar energy in the evening. Also, we measured temperature of a collector plate under actual solar radiation in a fine day.

An Improvement in the Solar Water Heating Systems by Thermal Storage Using Phase Change Materials

Solar Energy ◽  
2006 ◽  
Author(s):  
D. Vikram ◽  
S. Kaushik ◽  
V. Prashanth ◽  
N. Nallusamy
Keyword(s):  
Phase Change ◽  
Solar Collector ◽  
Storage Tank ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Control Device ◽  
Hot Water ◽  
Water Heater ◽  
Storage Unit ◽  
Solar Water

The present work has been undertaken to study the feasibility of storing solar energy using phase change materials (like paraffin) and utilizing this energy to heat water for domestic purposes during nighttime. This ensures that hot water is available through out the day. The system consists of two simultaneously functioning heat-absorbing units. One of them is a solar water heater and the other a heat storage unit consisting of Phase Change Material (PCM). The water heater functions normally and supplies hot water during the day. The storage unit stores the heat in PCMs during the day and supplies hot water during the night. The storage unit utilizes small cylinders made of aluminium, filled with paraffin wax as the heat storage medium and integrated with a Solar Collector to absorb solar heat. At the start of the day the storage unit is filled with water completely. This water is made to circulate between the solar collector and the PCM cylinders. The water in the storage tank receives heat form the solar collector and transfers it to the PCM. The PCM undergoes a phase change by absorbing latent heat, excess heat being stored as sensible heat. The water supply in the night is routed to the storage unit using a suitable control device. The heat is recovered from the unit by passing water at room temp through it. As water is drawn from the overhead tank, fresh water enters the unit disturbing the thermal equilibrium, causing flow of heat from PCM to the water. The temperature of the heated water (outlet) is varied by changing the flow rate, which is measured by a flow meter. The storage tank is completely insulated to prevent loss of heat. The performance of the present setup is compared with that of a system using same PCM encapsulated in High Density PolyEthylene (HDPE) spherical shells.

scholarly journals EXPERIMENTAL INVESTIGATION OF ENERGY CHARACTERISTICS OF EVACUATED TUBE HEAT-PIPE SOLAR COLLECTOR SYSTEM

2015 ◽  
Author(s):  
Antanas KAVOLYNAS ◽  
Rolandas DREJERIS
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Flow Rate ◽  
Solar Collector ◽  
Storage Tank ◽  
Hot Water ◽  
Heat Transfer Agent ◽  
Energy Characteristics ◽  
Collector System ◽  
Evacuated Tube

Evacuated tube heat-pipe solar collector system with closed heat pipe has been experimentally investigated. Experiments have been fulfilled using the solar imitator whose energy irradiance on the surface of the solar collector at the constant ambient conditions is 800 W/m². Energy characteristics of the solar collector system with different flow-rates of the heat-transfer agent have been investigated using various flow-rate speeds of the heat-transfer agent. It has been stated that the increase of the flow-rate of the heat-transfer agent in the system from 0.01 to 0.12 kg/s would minimize the average collector efficiency from 0.81 to 0.55. When the reduced flow-rate of the heat-transfer agent has been used in the system, the higher temperature of the hot water is reached in the storage tank and at the same time the temperature of the heat-transfer agent in the system is increased. Thus, more energy has been lost in the pipeline and hot water storage tank, but less energy is used for the circulation of the heat-transfer agent energy. Increasing the agent flow-rate speed in the system has reduced the heat losses in the pipeline, but more energy is used for the energy circulation of the heat-transfer agent. Therefore, the medium efficiency of the solar collector system has changed insignificantly (0.47 ± 0.01).

scholarly journals Heliosystem of Auxiliary Heat Supply for a Mining Enterprise

2020 ◽  
Vol 7 (1) ◽  
pp. G9-G14
Author(s):  
S. Shkrylova ◽  
V. Kostenko ◽  
I. Skrynetska
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Electric Power ◽  
Thermal Energy ◽  
Solar Collector ◽  
Alternative Energy ◽  
Experimental Studies ◽  
Hot Water ◽  
Ecological Crisis ◽  
Stable Operation

In the conditions of the global ecological crisis in the world and Ukraine, the issue of finding alternative energy sources becomes relevant. One of the most common types of renewable energy is solar energy. In Ukraine today, the most promising direction of using solar energy is its direct transformation into low-potential thermal energy. To get electric power, solar radiation is the mere alternative to electric power generated from mined fuel, and without the pollution of air and water, or adverse consequences manifested in global warming. The disadvantage of this type of installation is the limitation of the duration of light time, as well as the effect of cloudiness. During the day, the number of solar radiation changes, to stabilize it is necessary to accumulate and accumulate it for further use, the technical implementation of stable operation of solar installation due to the use of terrestrial radiation and the accumulator of a specific part of solar energy is proposed. The purpose of the work is experimental studies to ensure the stable operation of the solar collector under cloudy conditions. The paper is aimed at the stabilization of the operation of the solar installation and to obtain additional heat after the Sun’s cloud cover. The use of a solar thermal collector is advisable in solar heating and hot water systems in conditions of alternating solar radiation. The results of physical modeling have proved the efficiency of the method of combining types of thermal radiation, due to the accumulation of energy it is possible to increase the quantitative index of solar energy in the conditions of cloudiness by 3 times Keywords: alternative energy, solar energy, solar collector, thermal energy, clouds, terrestrial radiation, ecology.

scholarly journals MATHEMATICAL MODEL OF HEAT SUPPLY INSTALLATION AS AN OBJECT OF ECONOMIC EFFICIENCY AND AUTOMATION

2020 ◽  
Vol 2 (2) ◽  
pp. 69-74
Author(s):  
S. HORIASHCHENKO ◽  
◽  
Yu. KRAVCHIK ◽  
O. PIDGORNYI ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Solar Energy ◽  
Water Supply ◽  
Solar Collector ◽  
Heat Supply ◽  
Hot Water ◽  
Energy Sources ◽  
Solar Collectors ◽  
Efficient Operation

Solar energy is widely used in cases where the inaccessibility of other energy sources in combination with a sufficient amount of solar radiation justifies it economically. With the help of a system of solar collectors, you can significantly reduce energy costs for hot water supply and heating. In addition, the use of this system helps reduce CO2 emissions. The potential of solar energy in Ukraine is quite high. According to the climatic conditions of our region, solar activity is slightly lower than in the southern regions, so the use of flat solar collectors, which use both direct and scattered solar radiation, is effective for our region. The use of heat collectors in the home for water supply and heating of small areas is economically feasible, as it does not require significant costs. Heat supply plants using non-traditional energy sources are promising in terms of fuel savings and reduction of harmful effects on the environment. To increase the service life, economical use of heat and fuel, efficient operation of the installation requires the use of automation. The article considers the development of a mathematical model of a heat supply installation based on a solar collector. For automated control of the heat supply installation, it is necessary to know the properties of this installation as a whole and its individual elements. For this purpose, models of individual elements of the heat supply installation in a linear approximation are considered. The solar collector is conditionally divided into two parts. The model of the ground heat exchanger is developed. Also e battery models and consumer premises. The given matrices of elements of installation of heat supply are united in the uniform system of matrices. The obtained results allow estimating in advance efficiency of their use and economic attractiveness.

Solar Water Heater Design for Houses in Arid Zones

2013 ◽  
Author(s):  
Ramses Vega ◽  
Hector E. Campbell ◽  
Juan de Dios Ocampo ◽  
Diego R. Bonilla G.
Keyword(s):  
Solar Collector ◽  
Extreme Temperature ◽  
Hot Water ◽  
Arid Zones ◽  
Water Heater ◽  
Collector System ◽  
End Use ◽  
Flat Plate Solar Collector ◽  
Demand Profile ◽  
Heater Design

This paper shows the simulation and design of a flat plate solar collector system, used to feed hot water to a typical home located in the city of Mexicali, Baja California, México. The system consists of a solar collector, a storage tank, a water pump and accessories and special tools that allow its proper operation. Analyzing the consumption and end use of water in a typical House, a demand profile is established, which combined with the weather information of the region, constitutes the input parameters required for the simulation of the system, which is performed with the software package TRNSYS. Mexicali, due to its location (latitude 32 °, longitude 114 °) and semi-desert condition presents high temperatures in the summer and low in winter, so the design and operation of such systems require special features, not always considered in the conventional ratings. This paper presents methods for simulation and design oriented to optimize the dimensioning and operation of this type of solar heaters in regions with extreme temperature conditions.

scholarly journals Evaluation of Solar Ponds and Aplication Area

2018 ◽  
Vol 64 ◽  
pp. 02002
Author(s):  
Sogukpinar Haci ◽  
Bozkurt Ismail ◽  
Cag Serkan
Keyword(s):  
Solar Energy ◽  
Electricity Generation ◽  
Storage Capacity ◽  
Heat Storage ◽  
Storage Systems ◽  
Hot Water ◽  
Temperature Variations ◽  
Solar Ponds ◽  
Salty Water ◽  
Solar Pond

Solar ponds are heat storage systems where solar energy is collected and stored thermally. Solar ponds were discovered during the temperature variations in the lower regions of existing saltwater pond in the area is found to be higher than their surface. Later, it was constructed artificially and started to be used. These systems have heat storage capacity at moderate temperatures. Solar pons are used in many areas such as electricity generation, heating the environment, meeting the need of hot water, drying food and obtaining fresh water from salty water. In this study, the studies about solar ponds were summarized, the construction of solar pond was explained, and the application areas were examined.

Flat-Plate Solar Collector in Transient Operation: Modeling and Measurements

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Ahmad M. Saleh ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Differential Equations ◽  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Ambient Air ◽  
Fluid Temperature ◽  
Ambient Conditions ◽  
Flow Rates ◽  
Collector System ◽  
Nodal Model

This paper describes a mathematical model for simulating the transient processes which occur in liquid flat-plate solar collectors. A discrete nodal model that represents the flat-plate solar collector's layers and the storage tank is employed. The model is based on solving a system of coupled differential equations which describe the energy conservation for the glass cover, air gap, absorber, fluid, insulation, and the storage tank. Inputs to the model include the time-varying liquid flow rate, incident solar radiation, and the ambient air temperature, as well as the volume of liquid in the storage tank and initial temperature of the system. The system of differential equations is solved iteratively using an implicit, finite-difference formulation executed with Matlab software. In order to verify the proposed method, an experiment was designed and conducted on different days with variable ambient conditions and flow rates. The comparison between the computed and measured results of the transient fluid temperature at the collector outlet shows good agreement. The proposed method is extremely general and flexible accounting for variable ambient conditions and flow rates and allowing for a geometrical and thermophysical description of all major components of the solar collector system, including the storage tank. The validated, general model is suitable to investigate the effectiveness of various components without the necessity of carrying out experimental work, and the flexible computational scheme is useful for transient simulations of energy systems.

Design, Implementation, and Evaluation of Thermal Performance of a Thermosiphon Flat-Plate Solar Collector for Water Heating in Ecuadorian Coastal Region

2017 ◽  
Author(s):  
Carola Sánchez ◽  
José Macías ◽  
Jonathan León ◽  
Geancarlos Zamora ◽  
Guillermo Soriano
Keyword(s):  
Flat Plate ◽  
Thermal Performance ◽  
Solar Collector ◽  
Storage Tank ◽  
Hot Water ◽  
Attractive Alternative ◽  
Local Market ◽  
Water Heating ◽  
Water Storage Tank ◽  
Flat Plate Solar Collector

Passive solar water heating (SWH) is a convenient method to meet domestic hot water requirements in rural areas, where electricity may not be available or fuel supply might be limited due to difficult access. In this work, a low-cost thermosiphon flat-plate solar collector alternative is presented. The design was purposely limited to materials and recyclable products widely available in the local market, such as Tetra Pak, plastic bottles, and polypropylene (PP) fittings and pipes. Since PP is a thermoplastic polymer, a poor heat conductor, it was necessary to ensure a suitable system isolation to obtain an optimum thermal performance, comparable to commercial solar collectors. The design was built and tested in Guayaquil, Ecuadorian coastal city. Six inexpensive temperature sensors were placed at the entrance and exit of the collector, on the flat-plate and inside the hot water storage tank. Data was recorded using an Arduino single-board computer and later analyzed with the data gathered via weather station. The implementation costs of the system are approximately US$300, the overall performance during January 2017 fluctuated between 54% and 23%, and the storage tank temperature range varied from to 46°C to 33°C. Due to its reliability and affordable cost, the SWH system is an attractive alternative to an Ecuadorian commercial solar flat plate collector, which price is set between US$600 and US$700, it has an efficiency around 60%, and the average annual storage tank temperature is 62°C.

DESIGN AND PERFORMANCE ANALYSIS OF AN AUTOMOBILE-REMOVABLE SOLAR SYSTEM FOR WATER AND CABIN HEATING

2014 ◽  
Vol 38 (4) ◽  
pp. 505-515
Author(s):  
Mohamed Bentrcia
Keyword(s):  
Saudi Arabia ◽  
Performance Analysis ◽  
Solar System ◽  
Solar Energy ◽  
Solar Collector ◽  
Storage Tank ◽  
Solar Heating ◽  
Passenger Compartment ◽  
Camping Trip ◽  
And Performance

A detachable, automotive solar system for water and passenger compartment heating is developed. The study shows that an adjustable 1 m2 solar collector is sufficient to satisfy the needs of a small group during a short camping trip in Saudi Arabia desert. Also it is found that an adequate water temperature in the storage tank, due to ambient solar heating, is maintained in all cold months, except December when it is insufficient. Among the advantages of the system is its entire operation on renewable solar energy and its ability to heat the car compartment whenever the heated water reaches the required temperature and solar energy is still available.

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