Performance Evaluation of an Asymmetric Hybrid Solar Collector: Effect of Nanofluids on the Electrical and Thermal Energy Production

2016 ◽  
Author(s):  
M. T. Nitsas ◽  
I. P. Koronaki ◽  
A. S. Kontos

The scope of this work is the analysis of the electrical and thermal performance of an asymmetric hybrid solar collector PVT and the prospect of the installation of a system consisting of these collectors in the Mediterranean region. For the purpose of this work, the Solarus V11 PVT collector (readily available in our laboratory) was chosen and numerically modeled. The main asset of this collector is its asymmetric reflector that consists of a circular and a parabolic part leading to a maximum thermal energy production even in winter as the solar radiation is concentrated in the edge of the reflector rather than in the center of it. Using a software developed in Matlab, the calculated data are presented for both thermal and electrical energy and they are compared with the hot water and electrical energy requirements (per month) around the Mediterranean territory. Furthermore, a parametric study is conducted in order to investigate the effect of the mass flow rate and the PVT array configuration on the thermal and electrical production, as well as the efficiency of the solar cells of the system. Moreover, in order to increase the PV cell efficiency, nanofluids, i.e. mixtures of nanometer size particles well-dispersed in a base fluid, are proposed as heat transfer fluids and the analysis for the performance evaluation is conducted for different nanoparticle loadings.

2013 ◽  
Vol 34 (1) ◽  
pp. 19-39 ◽  
Author(s):  
Eugeniusz Orszulik ◽  
Jan Jachyra ◽  
Andrzej Wasylewicz

Abstract The paper presents a concept of producing energy on the basis of modern alternative fuels to be burnt in low- and medium-power stokerfired boilers. The thermal energy contained in water vapour and hot water will be utilized in producing, in combination, of electrical energy, and for heating of cubature objects. Modern alternative fuels in the form of briquettes and pellets will be produced from hard coals and municipal waste other than hazardous. There have been presented the properties of alternative fuels obtained, and the concept of their utilization in the process of energy production in cogeneration.


2019 ◽  
Vol 41 (1) ◽  
pp. 86-107 ◽  
Author(s):  
Ahmad Riaz ◽  
Ruobing Liang ◽  
Chao Zhou ◽  
Jili Zhang

The hybrid photovoltaic-thermal system has shown great progress. Electrical energy is produced from PV panels while thermal energy is produced via a working fluid carried through the panels. In this paper, the vertical PV/T is introduced using working fluids such as air and liquid, which serve to control the excess temperature of the PV panels as well as to collect heat to be made available as thermal energy. Installations of PV/T systems on building façades, as well as integration with other technologies such as heat pipe and heat pump are also discussed. Current studies of such building integration technologies are also explored, including the scale of application. This study aims to provide constructive information which can be used in future development of building facades for large-scale applications, to contribute to future sustainable development. Practical application: This study helps researchers and engineers who are considering photovoltaic thermal systems for building façades to have better understanding of its effect on electrical and thermal energy – for space heating, fresh air supply and hot water supply – using an active building envelope.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Abhishek Saxena ◽  
Varun Goel

Solar energy can be converted into different forms of energy, either to thermal energy or to electrical energy. Solar energy is converted directly into electrical power by photovoltaic modules, while solar collector converts solar energy into thermal energy. Solar collector works by absorbing the direct solar radiation and converting it into thermal energy, which can be stored in the form of sensible heat or latent heat or a combination of sensible and latent heats. A theoretical study has been carried out to rate the various thermal energy storage commonly used in solar air heaters. During the investigations rock bed storages have been found to be low type thermal heat storage, while phase change materials have been found to be high heat thermal storages. Besides this, a few other heat storing materials have been studied and discussed for lower to higher ratings in terms of thermal performance purposely for solar heaters.


2018 ◽  
Vol 82 (1) ◽  
Author(s):  
Юрий Анатольевич Селихов ◽  
Виктор Алексеевич Коцаренко

Европейские страны демонстрируют высокие возможности простого преоб­разования солнечной энергии в тепловую энергию, которая может успешно использо­ваться для обеспечения различного рода технологических, отопительных и бытовых потребностей. Кроме того, ввод в эксплуатацию сол­нечных установок улучшает экологическую ситуацию района потребления тепловой энер­гии за счет снижения объемов выбросов загряз­няющих веществ, к которым относятся продукты сгорания органического топлива, используемого для производства тепловой энергии. В настоящее время в южных районах Украины уже используются солнечные установки для горячего водоснабжения и отопления. Однако, внедрение новых энергетических и экономически выгодных установок идет медленными темпами, что объясняется довольно высокими стоимостными показате­лями, как отечественных, так и зарубежных установок. Таким образом, на наш взгляд, является актуальной концепция создания новых солнечных установок, наиболее привлекательных для потенциаль­ного потребителя. Реализация данной кон­цепции возможна при таком варианте исполнения солнечных установок, когда затраты на выработку тепловой энергии с помощью этих установок будут ниже уровня суммарных затрат на получение тепловой энергии традиционными способами (в частности, в котельных установках). Однов­ременно с этим, срок окупаемости солнечных установок должен быть соизмерим с гарантийным сроком их эксплуатации. Для выполнения поставленных условий представ­ляется целесообразным разработка таких конструкций солнечных коллекторов, которые позволяли бы минимизировать затраты на их изготовление, монтаж и обслуживание. Это может достигаться за счет использования дешёвых отечественных материалов, выпуск которых гарантирован в достаточных объемах на протяжении длительного срока. Разработка, изготовление и внедрение двухконтурных солнечных установок позволило круглогодично эксплуатировать солнечный коллектор, но капитальные и эксплуатационные затраты при этом были  на таком уровне, что для полной окупаемости солнечной установки могло понадобиться более пяти лет, так как солнечные коллектора изготавливались из металла.  В рамках сформулированной задачи нами был разработан и изготовлен солнечный коллектор из полиэтиленовой пленки. Предлагается двухконтурная солнечная установка для горячего водоснабжения и отопления, у которой солнечные коллектора изготовлены из полиэтиленовой пленки. Такая установка разработана, изготовлена и запущена в эксплуатацию в одном южном регионе Украины. На установке были получены экспериментальные результаты работы установки в разных режимах в течение года. После обработки этих данных были получены обобщающие зависимости: плотности теплового потока от температуры теплоносителя в коллекторе, времени работы установки в течение светового дня и расхода теплоносителя; коэффициента полезного действия от плотности теплового потока; максимального коэффициента полезного действия от максимальной плотности теплового потока; количества теплоты при конвекции от скорости натекания ветрового потока от 1 до 6 м/с на внешнюю поверхность солнечного коллектора. Зависимости получены при разных объемных расходах V от 0,5 до 3,0 м3/ч теплоносителя. Максимальная погрешность проведенных расчетов не превышает 5 %.  European countries demonstrate high opportunities for simple conversion of solar energy into thermal energy, which can be successfully used to provide various types of technological, heating and domestic needs. In addition, the commissioning of salt plants improves the ecological situation in the area of consumption of thermal energy by reducing emissions of polluting substances, which include combustion products of organic fuel used for the production of thermal energy.  At present, solar installations for hot water supply and heating are already used in the southern regions of Ukraine. However, the introduction of new energy and economically advantageous plants is proceeding slowly, which is explained by rather high cost indices, both domestic and foreign installations.Thus, in our opinion, the concept of creating new solar installations that are most attractive to a potential consumer is relevant. Implementation of this concept is possible with such an option of solar installations, when the cost of generating thermal energy using these facilities will be lower than the total cost of obtaining thermal energy by traditional methods (in particular, in boiler plants). However, with this, the payback period of solar installations should be commensurate with the warranty period of their operation. To fulfill the set conditions it is advisable to develop such designs of solar collectors that would allow to minimize the costs of their manufacture, installation and maintenance. This can be achieved through the use of cheap domestic materials, the release of which is guaranteed in sufficient quantities over a long period. The development, production and implementation of dual-circuit solar installations allowed the solar collector to be operated year-round, but the capital and operating costs were at such a level that it would take more than five years to fully pay for the solar installation, since the solar collectors were made of metal. Within the framework of the formulated task, we developed and manufactured a solar collector made of polyethylene film. A double-circuit solar installation is proposed for hot water supply and heating, in which the solar collectors are made of polyethylene film. Such an installation is designed, manufactured and commissioned in one southern region of Ukraine. Experimental results of the installation in different modes during the year were obtained at the plant. After processing of these data, generalizing dependencies were obtained: the heat flux density from the coolant temperature in the collector, the operating time of the installation during the daylight and the flow of the coolant; coefficient of efficiency from the density of heat flow; the maximum efficiency from the maximum heat flux density; the amount of heat in convection from the rate of leakage of the wind flow from 1 to 6 m / s on the outer surface of the solar collector. Dependencies were obtained at different volumetric flows V from 0.5 to 3.0 m3 / h of the heat carrier. The maximum error in the calculations does not exceed 5%.


Author(s):  
RAMESH C ◽  
SEKAR M

The depletion of conventional energy source, the need for unconventional energy is focused on solar energy as it is avail plentiful. Converting the solar energy in to thermal energy is the effective way of utilization of solar energy rather the conversion of electrical energy. This paper compared the behavior of solar collector at 30º and 45º angles with black chrome coated absorber plate without and with glass reflectors. In the view of performance enhancement of the collector, the reflector was adjusted to maximize the incident ray for every hour. It is found that the collector fixed at 30º with ground heats the water better and again the performance can be increased by the reflector.


2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Gianpiero Colangelo ◽  
Danilo Romano ◽  
Giuseppe Marco Tina

A thermal analysis of a new photovoltaic–thermal (PV–T) solar panel design, called thermal electric solar panel integration (TESPI), has been performed using radtherm thermoanalitics software. Combinations of different water flow rates and different panel configurations have been analyzed to determine which one produces best performance in terms of optimal PV efficiency and available thermal energy. Higher total panel efficiencies (thermal and electrical) were achieved in configurations utilizing the highest water flow rates, independently from the chosen configuration. However, high water flow rates translated into minimal net temperature differences between the PV/T panel inlet and outlet.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4171
Author(s):  
Ilze Polikarpova ◽  
Roberts Kakis ◽  
Ieva Pakere ◽  
Dagnija Blumberga

Solar energy transformation technologies are increasingly being used worldwide in the district heating sector. In the Baltic states, only one district heating company has implemented a large-scale solar collector field into its thermal energy production system, which is analyzed within this research. In this study, we analyzed the first year operation of the solar field, solar collector efficiency, and several influencing factors, i.e., ambient air temperature, heat carrier flow, and the temperature difference between the supply and return heat carrier temperatures. The study includes collecting and compilation of the data, analyzing influencing factors, and data analysis using the statistical analysis method. In addition, the research presents a simplified multi-regression model based on the actual performance of a large-scale solar field, which allows for forecasting the efficiency of solar collectors by taking into account the main operational parameters of the DH system. The results show that solar energy covers around 90% of the summer heat load of a particular district heating system. However, they also show room for improvements in producing all the necessary heat in the summer using solar energy. The regression analyses show that the most significant correlation between all parameters examined was obtained in May, reaching R2 = 0.9346 in solar field efficiency evaluation. This is due to several suitable conditions for solar energy production, i.e., placing solar collectors at an angle for them to be the most productive, having enough space in the storage tank, and the demand for thermal energy being still higher than in the summer months.


2020 ◽  
Vol 7 (1) ◽  
pp. G9-G14
Author(s):  
S. Shkrylova ◽  
V. Kostenko ◽  
I. Skrynetska

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.


Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 286
Author(s):  
Ryszard Zwierzchowski ◽  
Olgierd Niemyjski ◽  
Marcin Wołowicz

The paper presents an analytical discussion of how to improve the energy efficiency of the steam cushion system operation for a Thermal Energy Storage (TES) tank. The EU’s green deal 2050 target policy requires an increase in the energy efficiency of energy production and use, as well as an increase in the share of renewable energy in the overall energy production balance. The use of energy-efficient TES is considered as one of the most important technologies to achieve the objectives of this EU policy. The analyses presented in the paper of energy-efficient operation of steam cushion (SC) systems were carried out by using operational data received from three District Heating Systems (DHSs) that supply heat and electricity to one of the largest cities in Poland and are equipped with the TES systems. These three analyzed TESs differ in capacities from 12,800 to 30,400 m3, tank diameters from 21 to 30 m and shell height from 37 to 48.2 m. The main purpose of using a steam cushion system in the TES tank is to protect the water stored in it against the absorption of oxygen from the surrounding atmospheric air through the surge chamber and safety valves located on the roof of the tank. The technical solutions presented here for the upper orifice for charging and discharging hot water into/from the tank and the suction pipe for circulating water allow to us achieve significant energy savings in the steam cushion systems. Both the upper orifice and the end of suction pipe are movable through the use of pontoons. Thanks to the use of this technical solution, a stable insulating water layer is created above the upper orifice in the upper part of the TES tank, where convective and turbulent transport of heat from the steam cushion space to the hot water stored in the tank is significantly limited. Ultimately, this reduces the heat flux by approximately 90% when compared to the classic technical solutions of steam cushion systems in TES tanks, i.e., for the upper orifice and circulation water pipe. The simplified analysis presented in the paper and comparison of its results with experimental data for heat flow from the steam cushion space to hot water stored in the upper part of the TES tank fully confirms the usefulness of the heat-flow models used.


Sign in / Sign up

Export Citation Format

Share Document