In order to popularize the use of the solar-water heaters, especially in the residential and tertiary sectors with the third world, it appears to be necessary to reduce their cost while improving their performances. It is the object of this inte- grated storagecollector thus created and tested in the south of Tunisia. It is simply made up of a tank playing the double part of solar absorber and storage tank of warm water, of a glazing to profit from the greenhouse effect and of an insu- lating case. Its measured energy performances, by the method of input-output proves its effectiveness to produce hot water, in spite of its simplicity of manufacture, usage and maintenance. Indeed a temperature of water exceeding 70˚C is reached towards the afternoon True Solar Time, and for an efficiency of 7%. Thus, this type of collector with inte- grated storage is entirely satisfactory and could be available to larger mass.
274 Furthermore, the water temperature measurements at different heights in the storage tank show the thermo siphon effect. BSWH Solarwater heating applying thermo siphon is attractive, because it disregards the need for a circulating pump. This domestic BSWH system with a capacity of 100 litter per day is capable of achieving significant energy savings in hot climate countries particularly in the present situation of acute energy short age and most suitable to supply the needs of a family of four persons. Results specify that the project of the thermo siphon solarwater heating system was a success.
Abstract— Flat Plate SolarWater Heaters are widely used all over the world to utilize solar energy available abundantly in nature. To utilize solar energy during off sunshine hours, it becomes necessary to store the solar thermal energy and retain it as long as possible. Depth of water in a solar thermal collector is an important geometric parameter that influences Heat retention. A mathematical modelling of transient heat transfer was done for different water depths and validated with experimental studies to optimize the depth of water from maximum temperature and maximum heat retention view point.
concentrator. They found that the systems operated efficiently and were suitable for practical applications. Later on, Tripanagnostopoulos et al. (2002) developed four ICSSW heaters with stationary compound parabolic concentrating (CPC) reflectors. The systems consisted of single (STS models) and double (DTS models) horizontal cylindrical tanks placed in symmetric and truncated CPC troughs. In particular, these authors used two cylindrical tanks in the DTS-1 and DTS-2 models to increase temperature stratification. Part of the upper tank of the DTS-1 model was thermally insulated while the lower tank was not. For the DTS-2 model, a higher proportion of the cylindrical surface of the upper tank was thermally insulated than that of the lower tank. This insulation pattern shows that the upper tanks, in both DTS models, would store thermal energy better than their corresponding lower tanks, with the performance of thermal collection being opposite to that of thermal storage. The tanks in the DTS models were connected in series from the top part of the lower tank to the bottom part of the upper tank. They found that asymmetric CPC reflectors contributed to lower thermal losses and that the two interconnected tanks resulted in effective water temperature stratification. However, Fig. 17 of this reference shows that the water temperature in the top part of the lower tank was distinctly higher than the temperature in the bottom part of the upper tank for the DTS-1 system model, which indicates that water in the top part of the lower tank was hotter than that in the bottom part of the upper tank during heat
Narasimhe Gowda et al.  studied the heat transfer phenomena in the collector system were calculated by using theoretical model. To improve the thermal efficiency of the solarcollector system, inlet water temperature should be as low as possible. The efficiency increases more or less linearly with ambient temperature. Increasing the thickness of insulation beyond 5 cm is worthless. Efficiency will decrease with increase of wind speed. Transmission ratio of glass cover should be more than 0.95 in order to obtain higher thermal efficiency. Higher the ambient temperature higher is the efficiency because of less heat loss to the surrounding.
ABSTRACT: The energy is always a need to continue the life cycle with low cost and high efficiencies at the end of the day output. And engineering is always in the hunt of the new and best technology to furnish the vast and clean output which should be obviously friendly to the nature. So, it is intended to build a machine which can give more efficient and clean energy with low cost, powerful and also friendly to the nature, for that it is simple to switch the solar energy system. As everyone knows that the solar energy is enormous and abandon in nature and some thousand watts of heat energy is transmitted to our earth from the sun in the form of light every day. The PTSC (Parabolic Trough SolarCollector) technology is very useful as it is used for approximately all solar energy applications such as steam and power generation, water heating, air heating etc. The prototype of the parabolic trough concentrating collector is manufactured using the available materials (plywood, Reflective Aluminium sheet, storage tanks, and copper tube) and equipment in the workshop. An experimental setup has been developed to investigate the performance of the solar parabolic trough collector. Measurements of total direct radiation on the plane of the collector, ambient temperature, wind speed, water flow rate, and inlet and outlet temperatures of the water inside the absorber tube are collected and employed in studying the performance of the parabolic trough.
Abstract: Due to the environmental impact of energy usage and increased price of fusel fuel, consumers need to be encouraged to use renewable energy sources. The IHISSWHS (indirect heating integratedcollectorstoragesolarwaterheater system) is one of the most economical systems. It incorporates the collection of a solar energy component and a hot waterstorage component in one unit. The objective of this study was to investigate ways to enhance the thermal performance of the system. Two configurations of the system were studied: system with double row HX (heat exchanger) and tube length of 16.2 m, and system with single row HX and tube length of 8.1 m and 10.8 m. The service water tube inside diameter was also varied to 10.7 mm and 17.1 mm. The steady state continuity, momentum and energy equations were numerically solved, using FLUENT software. A standard k-ω turbulent model and surface-to-surface radiation model were used. The result showed that the system of 10.8 m tube length and single row HX provided higher outlet temperature than the system of 16.2 m and double row HX. Therefore, a significant reduction in cost and power usage can be achieved by using a single row HX.
A flat-plate built in storagewaterheater was has to be made for experimental investigation. The water tank has to be made out of galvanized sheet with gauge thickness of 1.5 mm. Wood is used for external casing. The Glass wool insulation is used on the sides and bottom of the water tank. Glass wool covering was 100 mm thick on each side. The gap between the absorber plate and the glass cover was 35 mm. When the ICS heater is inclined because of stratification a variable temperature distribution develops inside the tank. Tests have to be carried out between 10:00 AM and 4:00 PM. The rise in temperature has to be recorded for 15 minutes intervals. The parameters like inlet and outlet temperature of water, solar intensity, mass flow rate, absorber plate temperature, angle of inclination has to be considered while conducting the experiment and hence performance of the collector is to be found.
Fig. 5 shows the hourly temperature profile in the case where no PCM is introduced (configuration C0) and when it is added as indicated in the configuration C1 (see Fig. 1). Starting from t=0 (i.e. the sunrise), the outlet water temperature increases progressively and reaches its maximum value after approximately 10 hours. Before 15 hours from the sunrise, it is clearly seen that water temperature using a layer of PCM is less important than its temperature in the basic configuration. In fact, during this phase, the PCM stores the energy originating from the hot water circulating directly above it by means of convection heat transfer. The reverse tendency is observed just after this time showing the release of heat causing an increase in the water outlet temperature. Similar behavior is approximately seen in the next days with greater energy stored and released in the second day because of the relatively high solar fluxes. To illustrate more precisely the phase change phenomenon, the time variation of the PCM’s liquid fraction (average values) is given in Fig. 6. The mass flow rate was varied between 0.00075-0.003 kg/s and the other operating conditions were kept constant. It is clear that, for this first configuration, the PCM does not reach a complete melting since the plotted liquid fractions are all <65%. Moreover, for some flow rates, the PCM cannot be solidified completely (liquid fractions>0).This indicates that only a part of heat is stored/released which does not allow optimized utilization of this storage technique. Also, it can be seen that the melting fraction varies significantly with the change of the water flow rate.
flow rate of 0.5 L/min and average solar radiation data at 1.00PM till 5.00PM are filled in the ANSYS FLUENT. Water flow at 0.5 L/min all the time to collect heat from solarcollector to waterstorage tank for heat storing. The input data of solar radiation heat flux (W/m 2 ) are the
This paper covers the performance analysis of solar thermal cooling system for a computer lab situated in Government Engineering College Bharatpur using Flat Plate Collector, Evacuated Tube Collector and Compound Parabolic Collector. The computer lab has the floor and roof area 198.55 m 2 .The peak cooling load is calculated and it is 34.940 kW, accordingly 10TR vapor absorption cooling system was adopted. The 10 TR vapour absorption system was operated by a field of collector area varying from 80-120 m 2 . . The other parameters like hot storage tank, cold storage tank, pump, cooling tower etc are used. The simulation was carried out on TRANSOL Program for Bharatpur city situated in east of Rajasthan (INDIA). It can be conclude that solar thermal cooling system is technically feasible because it offers good solar fraction in the range of 0.52-0.75 in the considered city and collector areas. The primary energy savings reaches up to 52%.
Solar energy was one alternative energy that can be useful in life every day. For the usefulness of the potential solar energy, there are two kind technologies that have been applied, the solar thermal energy and the solar photovoltaic energy [1, 2]. Solarwaterheatercollector was a technology that using solar energy. Solarcollector widely used today in general design type flat-plate collector. However, this type of waterheater has a small efficiency [3, 4]. Efficiency can be improved by expanding the field of heat absorption. Performance solarcollector with addition of fins is better than without addition of fin [5, 6]. Figure-1 shows the wavy fins used in this study. The specification of wavy fins shown in Table- 1.
The design of parabolic trough collectors are structurally simpler than other types of but it requires continuous tracking so as to make sure that solar radiations are concentrated on the absorber tube throughout the day. The design of PTSC should be precise and the dimensions on x, y directions must be accurate to ensure the better optical efficiency of the system.
Phase change materials (PCM) are „„Latent‟‟ heat storage materials. The thermal energy transfer occurs when a material changes from solid to liquid, or liquid to solid. This is called a change in state, or „„Phase.‟‟ Initially, these solid–liquid PCMs perform like conventional storage material, their temperature rises as they absorb heat. Unlike conventional (sensible) storage materials, PCM absorbs and release heat at a nearly constant temperature. They store 5–14 times more heat per unit volume than sensible storage materials such as water, masonry, or rock. A large number of PCMs are known to melt with a heat of fusion in any required range. However, for their employment as latent heat storage materials these materials must exhibit certain desirable thermodynamic, kinetic and chemical properties. Moreover, economic considerations and easy availability of these materials has to be kept in mind.
convection heat absorbing plate or radiant heat loss are more difficult to solve. In addition, increasing the max- imum heat exchange area in the per unit area of the collector that is more difficult to achieve. Therefore, this type of collector is not ideal. The air heat transfer area of the permeable air collector in the unit area collectors is larger than non-permeable. With less slope top heat loss, the permeation type air collector is easy to form tem- perature field distribution with the upper low temperature and the lower high temperature. Among them, the porous layer of the absorber plate of the honeycomb structure has a special significance to prevent vertical con- vection heat loss and air vortex. Due to the complex structure, excessive material consumption and complex pro- cess, most of the honeycomb structures are less likely to choose and the large area promotion is limited by con- ditions. Condenser type dryer is the sun with a curved mirror to focus poly together to form a high-temperature region where the material to be dried quickly after entering the enclave height dry. Condenser type dryer which makes the air collector and drying chamber into one has complex device structure. This type dryer is special used for directional sun tracking system and average material transmission mechanism. Except for special use, this system is rarely used and also does not have the possibility of widespread popularization and application  as shown in Figures 8-10.
Generally Boilers are used to produce steam at high pressure than atmospheric pressure. The steam generator is also known as boiler. Steam is the most important working substance used for power generation in steam engines and in steam turbines. The generation of steam is done by evaporating the water in boilers at appropriate temperatures and pressures. A “Boiler” may be defined as a combination of equipments to generate steam from water by burning fuel. In industries the steam may be used for different purposes.A boiler is an enclosed vessel that provides a means for combustion heat to be transferred into water until it becomes heated water or steam. The hot water or steam under pressure is then usable for transferring the heat to a process. Water is a useful and cheap medium for transferring heat to a process. When water is boiled into steam its volume increases about 1,600 times, producing a force that is almost as explosive as gunpowder. This causes the boiler to be extremely dangerous equipment that must be treated with utmost care.
Fig.(1). A galvanized steel sheet of 2 mm thickness painted with ordinary blackboard paint was used as the absorber plate. The dimensions were (1 * 1 m), resulting in an absorber area of one m 2 . The storage tanks were constructing by bending and welding of the steel sheets, which formed the top, bottom, and sides. The each of three storage tanks was wrap with 5 cm of fiber glass wool insulation on all sides and bottom and housed in an outer woody box. The assembly of each heater was mounted on a steel stand to face south at an angle 45 o to the horizontal. This inclination is nearly 10 o above, the local latitude of 35.33 o N for Kirkuk, where the experimental tests were carried out, to provide mean maximum collection of solar energy incident on the collector during the winter months . The capacity of the each tank was 80 liter. Ordinary window glass of 4 mm thickness was used as the top transparent cover for tilted surface facing the sun. The distance between the absorber plate and the bottom surface of the glass was kept at 45 mm, which is within the recommended value for solar collectors [11, . According to these workers, such a distance was supposed to provide a good insulating gap for the conduction- convection heat transfer from the hot absorber plate to the cooler glass cover. The glass cover edges were sealed with silicon tape to prevent the leakage of the hot air from the gap between the absorbing surface and the glass cover. The refractive index and extinction coefficient of window glass were taken as 1.526 m -1 and 0.02 mm -1 . All construction work was performed at the technical institute of Hawija, Iraq (34 N o , 44 E o ).
After the water is heated gas boiler and enter the floor heating coil system, there is a comparison between the return water temperature T6 and the heat storagewater tank top T4. When T6 is higher than T4, the heating return water has the value of heat recovery. Three-way valve B is opened and water enters into the heat exchange coil. The heat storagewater tank is further heated to maximize the heat utilization. When the T6 is lower than T4, the three-way valve A is opened. The heating return water goes directly into the heating gas boiler and completes heating cycle.
Thermodynamic parameters were obtained by use of psychrometric calculator developed from Psychrometric charts that describe the thermodynamic process of hot air drying . The most common dehydration processes use hot air as the drying medium as the air delivers heat to the product in order to evaporate moisture. The properties of air, most easily understood by psychrometric relationships are critical to understanding the process of evaporation. The dry air can be visualized as a gaseous solution of dry gases in constant proportions and water vapor in varying amount. At least two properties of air must be known in order to use the chart to characterize the drying air. Amongst the properties of air that are critical to drying are absolute humidity, enthalpy or heat content, specific volume, and relative humidity. The thermodynamic changes that take place in a solar dryer include heating depicted line A-B of Fig. 3 whereby there is a rise in temperature from TA to TB at constant absolute humidity. The relative humidity reduces from hA to hB. This is followed by the heating phase depicted by line B-C whereby the air picks up moisture from the product and the temperature drops from the drying temperature attained by air inside the dryer TB to exit temperature TC. In this process, the relative humidity increases from hB to hC. The humidity ratio will increase from HB to HC. The initial enthalpy, hA, will change to hC at C’.