The effect of tank-interconnection geometry on temperature stratification in an integratedcollector-storage solar water (ICSSW) heater with two horizontal cylindrical tanks has been studied. The tanks were parallel to each other, and separated horizontally and vertically, with the lower tank fitted directly below a glass cover, and half of the upper tank insulated. In addition, a truncated parabolic concentrator was fitted below the tanks, with its focal line along the axis of the upper tank. The heater was tested outdoors with the two tanks connected in parallel (P), and S1- and S2-series configurations, with and without hot water draw-off. Water temperature was monitored during solar collection and hot water draw-offs. For the heat charging process, it was found that only the lower tank exhibited temperature
According to Kumar and Rosen (2011), using a double glass cover in the integratedcollector system is an efficient strategy for reducing the top heat losses. However, the air spacing between the upper and lower glass, and between the lower glass and the absorber surface, has an effect on the amount of heat losses. Manz (2003) investigated numerically the convective heat flow through an air layer in cavities of facade elements. The Rayleigh number was varied between 1000 and 10 6 in this study. It was changed by altering the temperature difference between the walls surrounding the air or by altering the distance between the walls. The result of Manz’s study suggested that the increasing Rayleigh number resulted in an increase in the velocity of the air which in turn increased the convective heat transfer. Therefore, at a high Rayleigh number the gap is not as effective in reducing the heat loss.
III. COMPUTATIONAL SIMULATION OF TRANSIENT HEAT TRANSFER IN AN INTEGRATEDCOLLECTOR STORAGE TYPE MOVABLE FLAT PLATE SOLAR WATER HEATER ( ICSMFPSWH ) A transient Heat transfer analysis was done with an assumed fair weather radiation data on a particular day in June for different ICSMFPSWH models as described in the l setup given in Fig. 2 to Fig.6. 16 mm square mesh size was selected in water zone and suitable finer mesh size near the plate boundary and in air zone were selected as shown in Fig. 6. Grid independence test was performed to test the convergence of solution with a finer mesh size of 8 mm near the absorber surface for water side and 4 mm mesh size near the glass and absorber surface for air side and the average variation percentage is found to be less than 0.17 and hence the grid convergence is confirmed to be satisfactory.
Due to the impact of energy usage on the environment and the increase in the price of fossil fuel, people must be encouraged to use renewable energy sources such as solar energy, wind power, hydraulic energy, geothermal energy and biomass energy. The indirect heating integratedcollector storage solar water heating system is one of the compact systems for domestic water heating. It incorporates a solar energy collection component and a hot water storage component into one unit. The indirect heating type is characterized by service water passing through a serpentine tube (a heat exchanger) that is immersed in the stored fluid. The objectives of this study were to investigate ways to reduce heat losses from the system and enhance heat gained by the service water with the aim of reducing both the initial and the running costs.
In regards to the heat balance in the indirect heating integratedcollector storage solar water heater system, the absorber surface is heated from the solar radiation which has been transmitted through the glass covers. During the daytime, the heat flows from the absorber to the storage and service water. When there is no solar radiation, the energy in the storage water flows to the absorber and service water. In both cases, the absorber loses some of the heat due to convection to the air in the lower gap, radiation to the lower-side walls (the side-wall surrounding the lower air gap spacing) and radiation to the lower glass cover. The lower glass cover loses heat due to convection to the air in the top gap and through radiation to the upper-side walls and to the top glass cover. The top glass cover loses heat due
MW. The characteristics of sun, solar energy measuring equipments, discussion on the thermal losses, and efficiency of flat plate collector are dealt in this project. The IntegratedCollector Storage (ICS) is the type solar water heater that has retained its existence for well over a century. The flat absorber plate ICS collector type is a relatively recent addition. An attempt is being made to increase the efficiency of the integratedcollector storage by analyzing the design, material selection. The efficiency has been found for various mass flow rates and different tilt angles and it was found that efficiency is higher for lower mass flow rate of 0.004ml/s.
This work presents a detailed analysis of an improved IntegratedCollector Storage Solar Water Heater (ICSSWH). This type of device is well suited for rural areas of Morocco because of its low cost, simplicity and compact structure. The innovation targeted in this system lies in the integration of a latent storage system by using a layer of phase change materials (PCM) in its lower part. Indeed, this integration is likely to increase the thermal energy delivered to the user during the night. The overall performance of the system depends on external climate data, type of PCM used and its mass, and flow rate of water. N-eicosane is considered as PCM in this application while hourly weather data corresponding to the city ER-RACHIDIA is used for the analysis. A detailed 2-D transient simulation has been established to optimize the system performance by studying the effect of different design variables and operating conditions. A deep analysis was also made to understand the PCM melting and solidification processes for a better exploitation of this storage technique. Optimized results are obtained when a mass flow rate of 0.0015 kg/s is used with a PCM thickness of 0.01 m and a set temperature of 313 K. Keywords:
Abstract— The integratedcollector water storage (ICWS) systems are simple type solar water heaters that can be used for the supply of hot water for domestic purposes, as alternative devices to the well known flat plate thermos phonic units (FPTU). Thermal protection of storage tanks is less effective in ICWS systems compared to FPTU systems and several methods are suggested to keep water temperature at a satisfactory level. Among them, the use of a selective absorber that reduces radiation thermal losses and double glazing, transparent insulation and inverted or evacuated absorber to suppress convection thermal losses, are suggested methods that preserve water storage heat. The use of compound parabolic collector (CPC) sym metric reflectors can result in ICS solar systems with effective water heating by using the non-uniform distribution of solar radiation on the cylindrical absorber surface.
A comprehensive study is necessary to explore the performance over a wide range of depth data in an IntegratedCollector storage type Flat Plate solar water Heater to compare and evolve optimum depth of water for maximum heat gain and retention. Hence a mathematical model of transient heat transfer in an IntegratedCollector Storage type movable flat plate solar water heater (ICSMFPSH) MODEL was developed to analyse the variation of temperature in 24 hours..
using five fins of 10 cm length was the best option. Gertzos, Caouris and Panidis  investigated the effect of the heat exchanger tube (HX) position relative to the storage tank wall, tube length and diameter for the system with circulating pump. The position where the tube was placed inside the tank touching the top and lower wall of the tank was found to be the best. The optimum diameter was found to be 16 mm and they found that there is no need for a further increase in the tube length of 21.68 m in their system. Mossad and AL-Khaffajy  investigated two configurations of the heat exchanger in an indirect heating flat plate collector without circulating pump. They concluded that both the initial and running cost of the system could be minimized by using a single row heat exchanger touching the top wall of the tank.
Tunisia, as all the similar countries of latitude profits from an extremely important sunning even in winter. Indeed, solar flux is on average for the country of 3.5 kWh/m²/d in winter and climbs up to 8 kWh/m²/d in summer while passing by 6 kWh/m²/j with the equinoxes. Thus the heating of water can be easily assured by solar energy without any time to claim to reach a satisfaction of 100% of hot water in winter. Solar heating water standard collector with plane integrated storage can be sufficient considering the strong value of fraction of insolation. The systematic re- course to the thermosiphon solar water heater always is thus not justified. Thus our project of design, realization and tests on the integrated storage collector solar water heater since 1990 meets this need well, more especially as it is reliable, inexpensive, and of easy and local con- struction [1,2]. Contrary to standard water-heater CPC (Compoud Parabolic Concentrator), our collector while being plane collects the totality of the solar radiation (di- rect and diffuse) without it not being for as much neces- sary to constantly direct it towards the sun. In a well shone day, the temperature of water can exceed 70˚C. The other side of the coin is night cooling, but actually it does not constitute a handicap because the sunny days are numer- ous and the fraction of insolation is high in these areas (0.45 < σ < 0.85).
ferent boundary conditions on the absorber plate. The re- sults show that the shape of the integrated-collector-storage systems has a great importance on the natural convection heat and fluid flow inside the system. The numerical results recording during the daytime heating period and during nighttime cooling period shows that the overall performance (after the successive heating and cooling periods) of the modified system is better. The modified system is able to store the water with higher temperature in the semi-circular top region than that of the conventional system. This hits our main objectives on reducing nighttime thermal losses. Future work should be made on the effect of the unsteady hot water consumption, which is exit from the upper part of the system and the cold water inlet from the lower part of the system on the overall thermal performance.
The numerical modeling and analysis og the solar integratedcollector storage system has been carried out using the commercial CFD software ANSYS FLUENT version 15. The geometry was modeled in Autodesk Inventor 2014 then imported to ANSYS FLUENT for mesh generation. An enthalphy porosity technique is used in FLUENT for modeling the solidification/melting process. In this technique, the melt interface was not tracked explicitly. Instead, a quantity called the liquid fraction, which indicates the fraction of the cell in the domain. Some assumptions were made in the numerical calculations: the heat conductivity and density of the phase-change material and the enclosures are constant; the values for the PCM were chosen as average of the solid and liquid material properties. The problem was solved in Three-dimensional domain. The heat transfer in the z direction and the convection heat transfer coefficient in the liquid PCM during the solidification process have been neglected.
The solar collector of the flat-thin box type made of galvanized sheet has acceptable characteristic parameters, which are similar to that of the tube-sheet type of collector but it is simpler to fabricate and has no selective coating. Using a fixed reflection mirror can make the temperature of the working fluid higher: on days of moderate radiation (below 800 W/m 2 ), the
Sanjay Kumar et al.[4 ] they had studied the performance of single solar still and double effect of active solar distillation having an area of 1mx1m, with and without water flow over the glass cover with anangle of 15 0 .They had study and shows that, an active solar still with water flow arrangements over the glass cover produces maximum amount of distillate output. The solar still operating with a double effect mode did not increase the daily output of still significantly because of the difficulties found in, maintaining low and uniform flow rates over the glass cover 10ml/min. collector length is of 1m, with a collector angle of 45 0 and having a flow rate with 40ml/min, two glasses maintaining a gap was that of 20 cm apart and using a pump having 0.2HP. An average of 7.5 l/day of distilled water was obtained in the active mode with water flow arrangement. an operation and maintenance was difficult. In a active and passive types of still without an arrangements of water flow in a system, an average output was 2.2 and 3.9 l/day. Its an operation and maintenance is difficult. Double effect mode did not iincrease the daily output significantly because of difficulties in maintaining reasonably low and uniform flow rates over the glass cover.
The simplest of solar cabinet dryer was presented by Othieno , it was very simple, and consists essentially of a small wooden hot box. The sides and bottom can be portable and can be constructed from wood or metal sheet. A transparent polyethylene sheet was used as cover at upper surface. Air holes are located on the sides of the drier for circulation. Portable indirect solar dryers also fabricated; made of wood and plywood as reported by Amouzou et al. . The absorber is made galvanized sheet metal painted black. The drying chamber can dry 10–15 kg of product in 3 days. The wooden frame was not weather-resistant (rain or wind), and the problem of waterproofing arose. Its useful life was 4 years. The multipurpose cement dryer was the same as the brace-type but made from breezeblock instead of wood. It is 4.82 m x 2.82 m and has load capacity of 80–100 kg. Both the collector for preheating the air and the drying chamber are covered with nine glass panel. To reduce the cost of the absorber, the black metal sheet was replaced with charcoal, a product that is available in rural areas. Bolaji  developed and evaluated a solar dryer using a box type absorber collector. The dryer consists of an air heater, an opaque crop bin, and a chimney. The box-type absorber collector made of a glass cover and black absorber plate was inclined at angle of about 20 degree to the horizontal to allow the heated air to rise up the unit with little resistance. He reported that the maximum efficiency obtained in the box-type absorber system was 60.5% while those of flat plate absorber and fin-type absorber were 21% and 36%, respectively. He calculated also the maximum average temperature inside the collector and drying chamber were 64 and 57.8°C, respectively, while the maximum ambient temperature observed was 33.5 °C. Bolaji and Olalusi  constructed and evaluated performance of a mixed-mode solar dryer for food preservation. They reported that the temperature rise inside the drying cabinet was up to 74% at about 3 hours immediately after noon. The drying rate and system efficiency were 0.62 kg/h and 57.5%, respectively. The rapid rate of drying in the dryer reveals its ability to dry food items reasonably rapidly to a safe moisture level. Results showed that during the test period revealed that the temperatures inside the dryer and solar collector were much higher than ambient temperature during most hours of the day-light.
There is a lot of not so good information out there on what makes a good solar air heating collector design, so we thought we would include a little info on solar air collector physics, what makes for a good design, and how one can measure and compare collectors accurately. On just about all solar thermal collectors, the sun shines through the glazing, and hits the collector absorber heating it. The air flows through the inlet and over or inside or through the absorber picking up heat as it goes. This heated air then flows out the collector outlet and into the room being heated. The main differences between air heating collector designs have to do with how the air flows over the absorber. In full sun, the incoming solar energy is about 1000 watts per square meter of collector area. Of this 1000 watts/sq m, about 10% is absorbed or reflected by the glazing and never gets to the absorber. Of the remaining solar energy, about 95% is absorbed by the absorber. So, for the 1000 watts/sq m that arrive at the collector face, about 850 watts/sq m end up actually heating up the absorber. Most of this 850 w/sq m that made it into the absorber end up going down one of two paths. One part is picked up by the air flowing through the collector and ends up heating the room, and the other part ends up being lost out the glazing. The job of the collector designer is to maximize the first part and minimize the 2nd part. It is very important to note that the heat output depends on both the Temperature Rise and the Airflow It is quite common for a collector to have a very high temperature rise and have a low heat output because the airflow is much low.
Packed bed units generally, represent the most suitable storage units for solar air heating systems where, the storage unit receives the heat from the collector during the collection period and discharges the heat to the building at the retrieval process. Two important considerations are involved in the design and operation of a packed - bed storage. Firstly, the rates of heat transfer that will take place between the airflow and solid particles is characterized by the volumetric heat transfer coefficient. Secondly, sizing of the bed involving determining, the four
This project to build mini prototype of the Automatic Rubbish Collector Using PLC System. Size of project very minimized if compare with the real size. Size of real project also depend from size of river or drain to install. This project very flexible and can do the upgrade process to give high performance.