Evacuated Tube Solar Collectors Integrated With Phase Change Materials and Silicone Oil

2017 ◽  
Author(s):  
Alexios Papadimitratos ◽  
Sarvenaz Sobhansarbandi ◽  
Vladimir Pozdin ◽  
Anvar Zakhidov ◽  
Fatemeh Hassanipour
Keyword(s):  
Phase Change ◽  
Solar Collector ◽  
Phase Change Materials ◽  
Silicone Oil ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Evacuated Tubes ◽  
Solar Water Heaters

This paper presents a novel method of integrating Phase Change Materials (PCMs) and Silicone oil within the Evacuated solar Tube Collectors (ETCs) for application in Solar Water Heaters (SWHs). In this method, heat pipe is immersed inside the phase change material, where heat is effectively accumulated and stored for an extended period of time due to thermal insulation of evacuated tubes. The proposed solar collector utilizes two distinct phase change materials (dual-PCM), namely Tritriacontane paraffin and Erythritol, with melting temperature 72°C and 118°C respectively. The integration of Silicone oil for uniform melting of the PCMs, utilizes the convective heat transfer inside the evacuated tubes, as this liquid polymerized material is well known for its temperature-stability and an excellent heat transfer medium. The operation of solar water heater with the proposed solar collector is investigated during both normal and stagnation (on-demand) operation. The feasibility of this technology is tested via small scale and large scale commercial solar water heaters. Beyond the improved functionality for solar water heater systems, the results from this study show show efficiency improvement of 26% for the normal operation and 66% for the stagnation mode compared with standard solar water heaters that lack phase change materials and silicone oil. The benefit of this method includes improved functionality by delayed release of heat, thus providing hot water during the hours of high demand or when solar intensity is insufficient such in a cloudy day and during night time.

Solar Thermal Collector With Multifunctional Absorber Layers

2017 ◽  
Author(s):  
Sarvenaz Sobhansarbandi ◽  
Patricia M. Martinez ◽  
Alexios Papadimitratos ◽  
Anvar Zakhidov ◽  
Fatemeh Hassanipour
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Black Body ◽  
Heat Accumulation ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters

Solar water heaters (SWHs) are a well-established renewable energy technology that have been widely adopted around the world. In this study we have significantly improved the Evacuated Tube solar Collectors (ETCs) by utilizing the “dry-drawable” Carbon Nanotube (CNT) sheet coatings to increase the solar energy absorption and Phase Change Materials (PCMs) to increase the heat accumulation for application in solar water heaters. The proposed solar collector utilizes a phase change material namely Octadecane paraffin, with melting temperatures of 28°C which is categorized as non-toxic with long-term chemical stability PCM. As PCMs particularly in powder form may not be effective by itself due to the poor heat transfer rate, low thermal diffusivity and thermal conductivity, by combining CNT layers with the high thermal diffusivity and thermal conductivity compare to phase change materials, we are able to overcome the shortcomings of PCMs and design an innovative and efficient solar water heater. With the current technology, we can provide a near ideal black body surface, absorbing a maximum of 98%, between 600–1100 nm, of solar light striking the surface, and providing additional spectral absorption which improves the performance of the solar heater. Applying CNT sheets in conjunction with PCM enables heat storage directly on the collector for a more constant output, even on a cloudy day and prolonged output of heat at night.

Thermal Properties Study of a Solar Water Heater Tank with a Mantle Exchanger

2014 ◽  
Vol 3 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Mourad Chikhi ◽  
Rabah Sellami ◽  
Nachida Kasbadji Merzouk
Keyword(s):  
Heat Exchanger ◽  
Renewable Energy Sources ◽  
Supply And Demand ◽  
Research Work ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Incentive Programs ◽  
Water Heaters ◽  
Solar Water Heaters

The development and use of renewable energy sources and technologies are becoming vital for the management of energy supply and demand. For development solar water heaters, the incentive programs are supported by the Algerian government to generalize the using of this kind of energy especially in Sahara. This study is a part of program to develop a new solar water heater in UDES (Algeria). In this research work, the thermal performance of a solar water heater with a mantle heat exchanger is investigated numerically using Comsol Multyphysics software. The objective is to investigate the influence of the mantle heat exchanger thickness on the performance of solar water heaters. The results show, for 160 liters capacity of the solar water heaters tank, the 13mm of the heat exchanger thickness leads to improve the efficiency of the solar water heater.

scholarly journals Thermal efficiency and cost analysis of solar water heater made in Rwanda

2018 ◽  
Vol 37 (3) ◽  
pp. 1147-1161 ◽  
Author(s):  
Esdras Nshimyumuremyi ◽  
Wang Junqi
Keyword(s):  
Cost Analysis ◽  
Thermal Efficiency ◽  
Solar Water Heater ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water Heating ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters ◽  
Made In

Solar water heating is a technology of capturing the energy from the sun's radiation for the purpose of raising the temperature of water from water supply temperature to the desired higher temperature depending on the use. There are many views and discussions on the questions of thermal efficiency of solar water heaters and their associated cost, especially different customers/users want to replace their existing conventional water heating energy by solar water heating systems. In this present paper, a deep investigation has been accomplished to determine thermal efficiency and cost analysis of solar water heater made in Rwanda. During manufacturing of solar water heater, the collector was the main part to emphasize on. The high efficiency of the system was achieved by replacing galvanized iron sheet by aluminum sheet slotted and black painted as an absorber plate. The ambient temperature and average solar radiation of the three sites where solar water heaters are installed were investigated. The used materials, specifications and sizing were discussed in this paper.

Characteristic Heat Removal Efficiency for Thermosyphon Solar Water Heaters During the System Application Phase

2004 ◽  
Vol 126 (3) ◽  
pp. 950-956 ◽  
Author(s):  
J. M. Chang
Keyword(s):  
Removal Efficiency ◽  
Empirical Model ◽  
System Application ◽  
Heat Removal ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Heat Removal Efficiency ◽  
Solar Water Heaters

The overall performance rating of a thermosyphon solar water heater should take into consideration its heat removal efficiency during the system application phase. This study employs a precise on-line operation to first identify physical heat removal patterns of a thermosyphon solar water heater, and then develops an empirical model for deriving its characteristic heat removal efficiency. This empirical model is in the form of a logarithmic curve, and has a high data correlation coefficient of 0.889 to 0.967. Based upon the empirical model, this study defines a characteristic heat removal efficiency parameter for thermosyphon solar water heaters. Finally, this study establishes a storage tank design method which enables the characteristic heat removal efficiency of the complete system to be optimized.

Preparation and Evaluation of PCMs by Macro Encapsulation for Solar Energy Storage

2021 ◽  
Vol 14 ◽  
Author(s):  
Sunita Routray ◽  
Vishal Agarwal ◽  
Ranjita Swain ◽  
Rudra Narayan Mohapatro
Keyword(s):  
Phase Change ◽  
Large Scale ◽  
Phase Change Materials ◽  
Low Cost ◽  
Storage System ◽  
Solar Water Heater ◽  
Water Heater ◽  
Latent Heat Storage ◽  
Solar Water ◽  
Thermal Fluids

Abstract: Phase Change Materials (PCMs) are used in a latent heat storage system for storing thermal energy. The thermal conductivity of PCMs is enhanced by macro encapsulation for large-scale use. This technique not only provides a self-supporting structure of PCM, also separates the PCM from thermal fluids and enhances the heat transfer rate. The current work involves the study of encapsulation of low-cost inorganic PCMs, such as Sodium nitrate (NaNO3), in a temperature range of 300 – 500˚C. Silicate coating is also applied to PCM capsules. A Solar water heater is then designed using the macro encapsulated PCM. The water heater consists of copper cylindrical pipes, filled with the phase change material. The efficiency of the solar water heater is found to be 22.5%.

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.

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