Design Parameters for High-Efficiency Hybrid PV/Thermal Solar Energy Systems

2011 ◽  
Author(s):  
Jerry A. Dutreuil ◽  
Hamid A. Hadim
Keyword(s):  
Solar Energy ◽  
High Efficiency ◽  
Waste Heat ◽  
Energy Systems ◽  
Energy Performance ◽  
Hot Water ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Improved Design ◽  
T System

With recently increasing focus on solar energy, there has been increased interest in hybrid PV/thermal (PV/T) solar energy systems. In the PV/T system, a thermal energy recovery system is implemented to remove waste heat from the PV cells, thereby decreasing their operating temperature, leading to enhanced overall energy performance of the PV cells. The possibility of the utilization of waste heat recovered for hot water or space heating makes the PV/T system highly attractive for building integration. The main objective of this study is to conduct a state-of-the-art review and compare existing PV/T systems in terms of the factors limiting their electrical and thermal performance. Critical design parameters for maximum efficiency of PVT systems are identified and practical recommendations for improved design of PVT systems are provided.

SOFC Management in Distributed Energy Systems

2011 ◽  
Vol 8 (3) ◽  
Author(s):  
Daniele Chiappini ◽  
Andrea Luigi Facci ◽  
Laura Tribioli ◽  
Stefano Ubertini
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Energy Systems ◽  
Hot Water ◽  
Pollutant Emissions ◽  
Heating Process ◽  
Distributed Energy ◽  
Utilization Factor ◽  
Distributed Power Generation

Among the distributed generation emerging technologies, solid oxide fuel cells (SOFCs) seem to be the most promising for small and medium power (up to 1 MW) as they feature extremely high efficiency and low pollutant emissions, and the high-grade waste heat can be utilized for space heating, process steam, and/or domestic hot water demands. As their main drawbacks are high cost and relatively short lifetime, much research is devoted to solve technological problems and to develop less expensive materials and mass production processes. However, even if SOFCs are close to commercialization and several demonstration units are already running, only few researches have been performed on their integration in power plants for distributed power generation, which are complex systems made up of different components that have to satisfy energy requirements (heat, electricity, and cooling). In this paper, we investigate the behavior of SOFCs in distributed energy systems and how their operation in terms of load and fuel utilization factor could optimize fuel consumption and/or minimize energy costs. The potential advantages of SOFCs related to their excellent part-load operation and their ability to meet and follow the highly noncoincident electric and thermal loads in either grid-connected or stand-alone configurations are discussed.

scholarly journals A Standard-Based Method to Simulate the Behavior of Thermal Solar Systems with a Stratified Storage Tank

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 266 ◽  
Author(s):  
Edoardo Alessio Piana ◽  
Benedetta Grassi ◽  
Laurent Socal
Keyword(s):  
Solar System ◽  
Solar Energy ◽  
Storage Tank ◽  
Hot Water ◽  
Design Parameters ◽  
Fluid Temperature ◽  
Forced Circulation ◽  
Solar Systems ◽  
Solar Field ◽  
The Impact

Thermal solar systems are interesting solutions to reduce CO 2 emissions and gradually promote the use of renewable sources. However, sizing such systems and analysing their behavior are still challenging issues, especially for the trade-off between useful solar energy maximization and stagnation risk minimization. The new EPB (Energy Performance of Buildings) standard EN 15316-4-3:2017 offers several methods to evaluate the performance of a forced circulation solar system. One of them is a dynamic hourly method that must be used together with EN 15316-5:2017 for the simulation of the stratified storage tank connected with the solar loop. In this work, such dynamic hourly method is extended to provide more realistic predictions. In particular, modeling of the pump operation due to solar fluid temperature exceeding a set threshold, or due to low temperature differential between solar field and storage tank, is introduced as an on–off control. The implemented code is applied to a case study of solar system for the preparation of domestic hot water and the impact of different design parameters is evaluated. The model predicts a higher risk of overtemperature lock-out or stagnation when the solar field surface is increased, the storage volume is reduced and water consumption is set to zero to simulate summer vacation periods. Finally, a simple modulating control with a time step of a few seconds to a few minutes is introduced, quantitatively showing the resulting benefits in terms of useful solar energy increase, back-up operation savings and reduced auxiliary energy use.

Experimental Daily Energy Performance of Flat Plate and Evacuated Tube Solar Collectors

2009 ◽  
Author(s):  
Enrico Zambolin ◽  
Davide Del Col ◽  
Andrea Padovan
Keyword(s):  
Solar Energy ◽  
Flat Plate ◽  
Energy Performance ◽  
Hot Water ◽  
Solar Collectors ◽  
Input Output ◽  
Evacuated Tube Collector ◽  
Daily Energy ◽  
Radiation Test ◽  
Evacuated Tube

New comparative tests on different types of solar collectors are presented in this paper. Tests have been performed at the solar energy conversion laboratory of the University of Padova. Two standard glazed flat plate collectors and one evacuated tube collector are installed in parallel; the evacuated collector is a direct flow through type with external CPC (compound parabolic concentrator) reflectors. The present test rig allows to make measurements on the flat plate, on the evacuated collector or on both simultaneously, by simply acting on the valves to modify the circuit. In this paper measurements of the performance of the evacuated tube collector and flat plate collectors working at the same conditions are reported. Efficiency in stationary conditions is measured following the standard EN 12975-2 [1] and it is compared with the input/output curves measured for an entire day. The main purpose of the present work is to characterize and to compare the daily energy performance of the two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is plotted against the daily incident solar radiation. Test runs have been performed in several conditions to reproduce different conventional uses (hot water, space heating, solar cooling).

Combined Cycle Engine Cascades Achieving High Efficiency

2016 ◽  
Author(s):  
Andy Schroder ◽  
Mark G. Turner ◽  
Rory A. Roberts
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Fuel Cell ◽  
Supercritical Carbon Dioxide ◽  
High Efficiency ◽  
Waste Heat ◽  
Combined Cycle ◽  
Design Parameters ◽  
Topping Cycle ◽  
Supercritical Carbon

Two combined cycle engine cascade concepts are presented in this paper. The first uses a traditional open loop gas turbine engine (Brayton cycle) with a combustor as the topping cycle and a series of supercritical carbon dioxide (S–CO2) engines as intermediate cycles and a bottoming cycle. A global optimization of the engine design parameters was conducted to maximize the combined efficiency of all of the engines. A combined cycle efficiency of 65.0% is predicted. The second combined cycle configuration utilizes a fuel cell inside of the topping cycle in addition to a combustor. The fuel cell utilizes methane fuel. The waste heat from the fuel cell is used to heat the high pressure air. A combustor is also used to burn the excess fuel not usable by the fuel cell. After being heated, the high pressure, high temperature air expands through a turbine to atmospheric pressure. The low pressure, intermediate temperature exhaust air is then used to power a cascade of supercritical carbon dioxide engines. A combined efficiency of 73.1% using the fuel lower heating value is predicted with this combined fuel cell and heat engine device. Details of thermodynamics as well as the (S–CO2) engines are given.

A Software Optimization of the Solar Energy System Performance

2014 ◽  
Vol 899 ◽  
pp. 199-204
Author(s):  
Lukáš Skalík ◽  
Otília Lulkovičová
Keyword(s):  
Solar System ◽  
Solar Energy ◽  
System Performance ◽  
Solar Collector ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Thermal Protection ◽  
Energy Systems ◽  
Energy System ◽  
Hot Water

The energy demand of buildings represents in the balance of heat use and heat consumption of energy complex in the Slovak national economy second largest savings potential. Their complex energy demands is the sum of total investment input to ensure thermal protection and annual operational demands of particular energy systems during their lifetime in building. The application of energy systems based on thermal solar systems reduces energy consumption and operating costs of building for support heating and domestic hot water as well as savings of non-renewable fossil fuels. Correctly designed solar energy system depends on many characteristics, i. e. appropriate solar collector area and tank volume, collector tilt and orientation as well as quality of used components. The evaluation of thermal solar system components by calculation software shows how can be the original thermal solar system improved by means of performance. The system performance can be improved of more than 31 % than in given system by changing four thermal solar system parameters such as heat loss coefficient and aperture area of used solar collector, storage tank volume and its height and diameter ratio.

Technical Considerations in a Zero Energy Home

2008 ◽  
Author(s):  
Dorothy S. Small
Keyword(s):  
Wind Power ◽  
Site Selection ◽  
Alternative Energy ◽  
High Efficiency ◽  
Energy Systems ◽  
Hot Water ◽  
Zero Energy ◽  
Domestic Hot Water ◽  
Backup System ◽  
Passive Solar

Building a zero energy home requires several major considerations: site selection for the home; considerations to use less; conservation of what you produce; and evaluation the best choices of renewable resources. This paper discusses the use of climate data collection software, heat loss and heat gain considerations and software; how to achieve a zero energy building and qualifying as a LEED (Leadership in Energy and Environmental Design) Certified Platinum home. Site selection is the first step. This first step can be taken after you have identified your goals. What alternative energy systems do you want to use? Do you want to use more than one alternative source? What other site considerations are important? In my case, I wanted to use solar energy as my primary alternative energy source. Why? I want comfort, reliability and ease of use. Other alternatives may require more maintenance. Wind power will be a second source that will be incorporated to produce electricity when the PV system can not produce. The site selected is a south facing mountain that has a steady breeze most of the time. Another consideration for me is the ability to use earth-sheltering as a measure of high efficiency construction. The south-facing mountain also provides the opportunity to “nestle” into the mountainside. Calculations and basis of design are presented. Using less is a key mindset that we all need to move toward. Using less does not mean that you suffer. This house will be comfortable year round with little effort because the house uses passive solar design for lighting and space heating, active solar hot water for additional heating of the floor and domestic hot water, and PV/wind/biodiesel generator backup to generate electricity for lighting and other typical electrical loads. The construction materials provide high R-values and green products that contribute to excellent indoor air quality. SIPs (Structural Insulated Panels) will be used as the structural components for the walls and roof. All electrical appliances, refrigerator, lighting, and washer/dryer were selected to use less electricity and water. Data describing the energy requirements are provided. Reuse all that you can. I am incorporating a masonry heater, also known as a Russian Fireplace. The combustion efficiency of the masonry fireplace is typically 92–94 percent with very low emissions. The masonry fireplace will provide passive mass for passive release of the woodburning energy during the evening and heat hot water coils in the fireplace as well (as the hot water backup system). The use of hard woods from the land will provide heat overnight, heat for cooking and supply additional BTUs for domestic hot water and radiant heat. Many of the building materials that are selected for construction are from the land; stone and whole cut wood from the land will be used for esthetic appeal and thermal mass thereby reducing harmful manufacturer’s emissions. My site is an excellent site for a hybrid solar and wind power (with a biodiesel generator as backup) system. The orientation and wind profile of the land is optimal for solar and wind energy applications. Site specific data and optimization of active solar, passive solar and PV/wind systems are presented. Life cycle costs are presented to show the cost comparison using Years-to-Payback and Return on Investment approaches for the energy systems and LEED certification costs for new construction.

Performance Analysis of Innovative Top Cooling Thermal Photovoltaic (TPV) Modules Under Tropics

2016 ◽  
Author(s):  
Swapnil Dubey ◽  
C. S. Soon ◽  
Sin Lih Chin ◽  
Leon Lee
Keyword(s):  
Solar Energy ◽  
Thermal Energy ◽  
Waste Heat ◽  
Heat Removal ◽  
Hot Water ◽  
Photovoltaic Module ◽  
Cell Temperature ◽  
Collector System ◽  
Pv Panel ◽  
Pv Module

The main focus area of this research paper to efficiently remove the heat generated during conversion of solar energy into electricity using photovoltaic (PV) module. The photovoltaic conversion efficiency of commercial available PV module varies in the range of 8%–20% depending on the type of solar cell materials used for the module construction, e.g. crystalline silicon, thin film, CIGS, organic, etc. During the conversion process, only a small fraction of the incident solar radiation is utilize by PV cells to produce electricity and the remaining is converted into waste heat in the module which causes the PV cell temperature to increase and its efficiency to drop. This thermal energy could be extract using air or water as a heat removal fluid to utilize in heating applications. The purpose of a solar photovoltaic module is to convert solar energy into electricity. The hybrid combination of photovoltaic module and thermal collector called Photovoltaic-thermal (PVT) module. Such PVT module combines a PV, which converts electromagnetic radiation (photons) into electricity, with a solar thermal module, which captures the remaining energy and removes waste heat from the PV module. Cooling of cells either by natural or forced circulation can reduce the PV cell temperature. The simultaneous cooling of the PV cells maintains their PV efficiency at a satisfactory level and offers a better way of utilizing solar energy by generating thermal energy as well. PVT system has higher overall efficiency as compared to separate PV and thermal collector. The heat output of a PVT module can be used for space heating or production of domestic hot water. This paper presents an innovative design of top cooling Thermal Photovoltaic (T-PV) module and its performance under outdoor weather condition of Singapore. T-PV collector is designed to flow fluid over the top of PV panel through a very narrow gap between the solar lens. This process improves heat removal process from PV panel, and hence, improves the electrical output of PV panel as compared to other PVT collector available in the market. By flowing the water from top of the PV panel will also provide better thermal efficiency. A T-PV collector system with storage tank, sensors, pump, flow meters, data logger and controls, have been installed at test-site located in Ngee Ann Polytechnic, Singapore. Performance analysis of T-PV collector system has been evaluated under the tropical climatic conditions of Singapore. It was found that T-PV module could produce additional electrical power as compared to standard PV panel of same capacity by operating at lower temperature. In addition to electricity, T-PV panel also generate the hot water up to 60 deg C at an average thermal efficiency of 41% for usage in residential and commercial buildings. The average thermal energy output was 3.1 kWh/day on typical day’s basis.

scholarly journals Recovery and Transport of Industrial Waste Heat for Their Use in Urban District Heating and Cooling Networks Using Absorption Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 291 ◽  
Author(s):  
Antonio Atienza-Márquez ◽  
Joan Carles Bruno ◽  
Alberto Coronas
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
District Heating ◽  
Distribution Networks ◽  
Energy Performance ◽  
Hot Water ◽  
Absorption System ◽  
Urban District ◽  
Heating And Cooling ◽  
Water Mass Flow Rate

The use of industrial excess heat in district heating networks is very attractive. The main issue is the transport of the heat from the point of generation to the local distribution network, in a way similar to the structure of electricity transport and distribution networks. Absorption systems have been proposed to transport and distribute waste heat using two absorption stations. In one of them (step-up station), industrial heat at a low temperature is pumped to a higher temperature to facilitate its transport and at the same time increase the temperature difference between the supply and return streams, in this way reducing the hot water mass flow rate circulating through the heat transport network. Heat is then used in a second absorption system (step-down station) to provide heat to a low temperature local district network. In this paper, several absorption system configurations are analyzed for both stations. A detailed thermodynamic analysis of each configuration is performed using selected energy performance indicators to calculate its global performance. The implementation of these kind of systems could enable the use of waste heat to produce heating and cooling for smart communities located a few dozens of kilometers away from industrial sites.

The Experimental Study of New-Type Water-Cooling PV/T Collector

2011 ◽  
Vol 374-377 ◽  
pp. 242-247 ◽  
Author(s):  
Ning Jun Li ◽  
Zhen Hua Quan ◽  
Yao Hua Zhao ◽  
Na Na Guo
Keyword(s):  
Experimental Study ◽  
Waste Heat ◽  
Hot Water ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Total Efficiency ◽  
Forced Circulation ◽  
Electrical Efficiency ◽  
Pv Modules ◽  
T System

A new photovoltaic/thermal (PV/T) system based on the micro plate heat pipe is established in this paper, and the experimental study is conducted for nature convection, forced circulation cooling and common PV module. the experiment carried out on May showed that the highest temperature were 50°C and 52°C respectively for nature convection and forced circulation cooling module, the daily average electrical efficiency were relatively increased by 13.1% and 6.1% than common PV modules, the total efficiency ηo reached 54.2% and 50.3%, and the primary-energy saving rate were 73.1% and 68%.the result indicates that in the new PV/T system the temperature of the PV modules is reduced, the electrical efficiency is keeping at a high level, and the waste heat can be made good use to get hot water, therefore the solar energy utilization efficiency was raised greatly.

scholarly journals Analysis of a modular high efficiency Polygeneration System in a Science and Technological Park

2014 ◽  
Vol 07 (2) ◽  
Keyword(s):  
High Efficiency ◽  
Renewable Energy Sources ◽  
Energy Performance ◽  
High Energy ◽  
Optimal Operation ◽  
Hot Water ◽  
Total Power ◽  
Heating And Cooling ◽  
High Efficient ◽  
Polygeneration System

Polygeneration systems refers to highly efficiency integrated systems characterized by the simultaneously production of different services (electricity, heating, cooling, water, etc) by means of several technologies using fossil and/or renewable energy sources. In many cases it is difficult to promote polygeneration projects due to its complexity. This complexity mainly comes from the high energy integration of the technologies involved in polygeneration plants and the high variability in the energy demand in many applications in the building sector that makes the design and optimal operation of these systems quite complex. The result is that without a very careful design and operation of these plants the economic viability is in many cases not clear. In this paper is presented an economic, energetic and environmental analysis of a polygeneration system in Cerdanyola del Vallès (Spain) built in the framework of the Polycity project of the European Concerto Program. This polygeneration system comprises three high efficient natural gas cogeneration engines with a total power capacity of about 10 MW with advanced thermal cooling facilities including a single effect hot water driven chiller and a double effect chiller of 5 MW driven directly by the exhaust gases of the engines. This plant provides electricity, heating and cooling to a new Science and Technological Park in development including a Synchrotron Light Facility through a district heating and cooling network with a total length of more than 30 km. The operational data for the energy performance analysis was taken using the plant SCADA system and a monitoring system specific for the cooling units in order to study in detail its performance. The results show that the polygeneration plant is an efficient way to reduce the primary energy consumption and CO2 emissions although it is not yet at its full capacity

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