Potential of Solar Thermal Energy for CCHP Systems

2009 ◽  
Author(s):  
Nelson Fumo ◽  
Louay M. Chamra ◽  
Vicente Bortone
Keyword(s):  
Energy Consumption ◽  
Solar Energy ◽  
Thermal Energy ◽  
Co2 Emission ◽  
Waste Heat ◽  
Energy Systems ◽  
Primary Energy ◽  
Solar Thermal ◽  
Solar Collectors ◽  
Solar Thermal Energy

Integrated energy systems combine distributed power generation with thermally activated components to use waste heat, improving the overall energy efficiency, and making better use of fuels. Use of solar thermal energy is attractive to improve combined cooling, heating, and power (CCHP) systems performance, particularly during summer time since the cooling load coincides very well with solar energy availability. Limitation of the use of solar systems is mainly related to high first cost and large surface area for solar energy harvesting. Therefore, solar thermal CCHP systems seem to be an alternative to increase the use of solar thermal energy as a means to increase energy systems overall efficiency and reduce greenhouse gases (GHGs) emissions. This study focuses on the use of solar collectors in CCHP systems in order to reduce PEC and emission of CO2 in office buildings. By using a base CCHP system, the energy and economic analysis are presented as the contribution of the solar system from the baseline. For comparison purposes, the analysis is made for the cities of Minneapolis (MN), Chicago (IL), New York (NY), Atlanta (GA), and Fort Worth (TX). Results show that solar thermal CCHP systems can effectively reduce the fuel energy consumption from the boiler. The potential of solar collectors in CCHP systems to reduce PEC and CO2 emission increases with the cooling demand; while the effectiveness of solar collectors to reduce primary energy consumption and CO2 emission, and the ability of the system to pay by itself from fuel savings, decreases with the number of solar collectors.

Design and Optimization of Integrated Distributed Energy Systems for Off-grid Buildings

2021 ◽  
pp. 1-27
Author(s):  
Jian Zhang ◽  
Heejin Cho ◽  
Pedro Mago
Keyword(s):  
Energy Storage ◽  
Optimal Design ◽  
Power Systems ◽  
Thermal Energy ◽  
Waste Heat ◽  
Carbon Dioxide Emission ◽  
Energy Systems ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Distributed Energy

Abstract Off-grid concepts for homes and buildings have been a fast-growing trend worldwide in the last few years because of the rapidly dropping cost of renewable energy systems and their self-sufficient nature. Off-grid homes/buildings can be enabled with various energy generation and storage technologies, however, design optimization and integration issues have not been explored sufficiently. This paper applies a multi-objective genetic algorithm (MOGA) optimization to obtain an optimal design of integrated distributed energy systems for off-grid homes in various climate regions. Distributed energy systems consisting of renewable and non-renewable power generation technologies with energy storage are employed to enable off-grid homes/buildings and meet required building electricity demands. In this study, the building types under investigation are residential homes. Multiple distributed energy resources are considered such as combined heat and power systems (CHP), solar photovoltaic (PV), solar thermal collector (STC), wind turbine (WT), as well as battery energy storage (BES) and thermal energy storage (TES). Among those technologies, CHP, PV, and WT are used to generate electricity, which satisfies the building's electric load, including electricity consumed for space heating and cooling. Solar thermal energy and waste heat recovered from CHP are used to partly supply the building's thermal load. Excess electricity and thermal energy can be stored in the BES and TES for later use. The MOGA is applied to determine the best combination of DERs and each component's size to reduce the system cost and carbon dioxide emission for different locations. Results show that the proposed optimization method can be effectively and widely applied to design integrated distributed energy systems for off-grid homes resulting in an optimal design and operation based on a trade-off between economic and environmental performance.

scholarly journals Solar Thermal Energy For Buildings – Current State and Perspectives

2020 ◽  
Author(s):  
Tamara Bajc ◽  
◽  
Milan Gojak
Keyword(s):  
Energy Consumption ◽  
Thermal Energy ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Primary Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Pv System ◽  
Heating And Cooling ◽  
System Power

Almost 50% of final energy consumption in Europe and worldwide is addressed to thermal energy, which is significantly higher than energy needs for electricity for lighting and electrical appliances and for traffic. Building sector takes a significant share (about 40 %) in total primary energy consumption. Limited amounts of fossil fuels, their negative impact on environment, high and unstable prices and import dependency of fuels caused intensive growth and usage of solar thermal energy in the world. Solar heating and cooling are the most important solar sector worldwide, where installed solar system power is about 500 GWth and it is higher than PV system power and also the power of solar thermal plants. Today, according to the total installed collector capacity, China dominates on first place, then Europe, while United States comes right after, according to the SHC Agency data for 2016. With a district solar thermal plant in municipality Pančevo, Republic of Serbia also has its place at a world solar thermal map. This paper presents a review of different sizes, number, installed power and types of solar collectors and other characteristics of built solar thermal systems worldwide. Potential for possible usage of solar thermal system was identified and technological and other challenges and perspectives for future growth in the field of solar thermal energy were discussed.

Optimal Design of Integrated Distributed Energy Systems for Off-Grid Buildings in Different U.S. Regions

2021 ◽  
Author(s):  
Jian Zhang ◽  
Heejin Cho ◽  
Pedro Mago
Keyword(s):  
Energy Storage ◽  
Optimal Design ◽  
Power Systems ◽  
Thermal Energy ◽  
Waste Heat ◽  
Carbon Dioxide Emission ◽  
Energy Systems ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Distributed Energy

Abstract Off-grid concepts for homes and buildings have been a fast-growing trend worldwide in the last few years because of the rapidly dropping cost of renewable energy systems and their self-sufficient nature. Off-grid homes/buildings can be enabled with various energy generation and storage technologies, however, design optimization and integration issues have not been explored sufficiently. This paper applies a multi-objective genetic algorithm (MOGA) optimization to obtain an optimal design of integrated distributed energy systems for off-grid homes in various U.S. climate regions. Distributed energy systems consisting of renewable and non-renewable power generation technologies with energy storage are employed to enable off-grid homes/buildings and meet required building electricity demands. In this study, the building types under investigation are residential homes. Multiple distributed energy resources are considered such as combined heat and power systems (CHP), solar photovoltaic (PV), solar thermal collector (STC), wind turbine (WT), as well as battery energy storage (BES) and thermal energy storage (TES). Among those technologies, CHP, PV, and WT are used to generate electricity, which satisfies the building’s electric load, including electricity consumed for space heating and cooling. Solar thermal energy and waste heat recovered from CHP are used to partly supply the building’s thermal load. Excess electricity and thermal energy can be stored in the BES and TES for later use. The MOGA is applied to determine the best combination of DERs and each component’s size to reduce the system cost and carbon dioxide emission for different locations. Results show that the proposed optimization method can be effectively applied to design integrated distributed energy systems for off-grid homes resulting in an optimal design and operation based on a tradeoff between economic and environmental performance.

Exergy Assessment of a Solar-Assisted District Energy System

2018 ◽  
Vol 11 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Behnaz Rezaie ◽  
Bale V. Reddy ◽  
Marc A. Rosen
Keyword(s):  
Solar Energy ◽  
Thermal Energy ◽  
Energy Demand ◽  
Fossil Fuel ◽  
Waste Heat ◽  
Energy System ◽  
Exergy Efficiency ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
District Energy

Background:District Energy (DE) is a technology capable of using renewable energy (e.g., solar thermal systems) and waste heat as energy sources efficiently. DE technology nonetheless has potential for improvement. Thermal Energy Storage (TES) can enhance DE performance significantly.Objective:An exergy analysis of a DE system which includes a solar thermal energy system and TES is performed, so as to improve understanding of its performance.Method:A case study based on the Friedrichshafen DE system in Germany is used to assess thermodynamically the role of solar energy and TES in a DE system. The system performance is separated into three modes: (1) fossil fuel is the only source of energy, (2) a discharging TES and fossil fuel provide heat for the DE system, and (3) solar energy and fossil fuels are the energy supplies. Exergy analyses are conducted for each performance mode and the overall DE system.Results:The results quantify the benefits of incorporating solar energy and TES on the performance of the Friedrichshafen DE system, and demonstrate that the overall exergy efficiency of the DE system increases from 23% to 27% with assistance of solar thermal collectors and TES, while the total energy efficiency increases from 83% to 87%.Conclusion:An increase of exergy efficiency is observed when TES is added to a DE system, due to a reduction in solar thermal energy loss by the TES, which allows more solar energy to be converted to useful energy to satisfy the DE system thermal energy demand.

New bounds for the thermal energy storage process with stationary input

1982 ◽  
Vol 19 (04) ◽  
pp. 894-899 ◽  
Author(s):  
J. Haslett
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Systems ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Storage Process

The process {Xn }, defined by Xn + 1 = max{Yn + 1 + αßX n, ßX n}, with αand ß in [0, 1) and {Yn } stationary, arises in studies of solar thermal energy systems. Bounds for the stationary mean EX are given, which are more general and in some cases tighter, than those previously available.

scholarly journals Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

2020 ◽  
Vol 12 (19) ◽  
pp. 8178
Author(s):  
Fahid Riaz ◽  
Kah Hoe Tan ◽  
Muhammad Farooq ◽  
Muhammad Imran ◽  
Poh Seng Lee
Keyword(s):  
Low Temperature ◽  
Thermal Energy ◽  
Waste Heat ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Low Grade ◽  
Solar Thermal Energy ◽  
Temperature Heat ◽  
Vapour Compression

Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75–100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system.

Solar Thermal Driven Cooling System for a Data Center in Albuquerque New Mexico

2010 ◽  
Author(s):  
N. Fumo ◽  
V. Bortone ◽  
J. C. Zambrano
Keyword(s):  
Energy Consumption ◽  
Data Center ◽  
Data Centers ◽  
Primary Energy ◽  
Continuous Operation ◽  
Solar Thermal ◽  
Primary Energy Consumption ◽  
Solar Collectors ◽  
Absorption Chiller ◽  
Solar Cooling

Data centers are facilities that primarily contain electronic equipment used for data processing, data storage, and communications networking. Regardless of their use and configuration, most data centers are more energy intensive than other buildings. The continuous operation of Information Technology equipment and power delivery systems generates a significant amount of heat that must be removed from the data center for the electronic equipment to operate properly. Since data centers spend up to half their energy on cooling, cooling systems becomes a key factor for energy consumption reduction strategies and alternatives in data centers. This paper presents a theoretical analysis of an absorption chiller driven by solar thermal energy as cooling plant alternative for data centers. Source primary energy consumption is used to compare the performance of different solar cooling plants with a standard cooling plant. The solar cooling plants correspond to different combinations of solar collector arrays and thermal storage tank, with a boiler as source of energy to ensure continuous operation of the absorption chiller. The standard cooling plant uses an electric chiller. Results suggest that the solar cooling plant with flat-plate solar collectors is a better option over the solar cooling plant with evacuated-tube solar collectors. However, although solar cooling plants can decrease the primary energy consumption when compared with the standard cooling plant, the net present value of the cost to install and operate the solar cooling plants are higher than the one for the standard cooling plant.

System and component modelling of a low temperature solar thermal energy conversion cycle

2013 ◽  
Vol 24 (4) ◽  
pp. 51-62
Author(s):  
Shadreck M. Situmbeko ◽  
Freddie L. Inambao
Keyword(s):  
Low Temperature ◽  
Solar Energy ◽  
Thermal Energy ◽  
Electrical Power ◽  
Solar Thermal ◽  
Working Fluid ◽  
Small Scale ◽  
Solar Thermal Energy ◽  
Solar Field ◽  
Conversion Technology

Solar thermal energy (STE) technology refers to the conversion of solar energy to readily usable energy forms. The most important component of a STE technology is the collectors; these absorb the shorter wavelength solar energy (400-700nm) and convert it into usable, longer wavelength (about 10 times as long) heat energy. Depending on the quality (temperature and intensity) of the resulting thermal energy, further conversions to other energy forms such as electrical power may follow. Currently some high temperature STE technologies for electricity production have attained technical maturity; technologies such as parabolic dish (commercially available), parabolic trough and power tower are only hindered by unfavourable market factors including high maintenance and operating costs. Low temperature STEs have so far been restricted to water and space heating; however, owing to their lower running costs and almost maintenance free operation, although operating at lower efficiencies, may hold a key to future wider usage of solar energy. Low temperature STE conversion technology typically uses flat plate and low concentrating collectors such as parabolic troughs to harness solar energy for conversion to mechanical and/or electrical energy. These collector systems are relatively cheaper, simpler in construction and easier to operate due to the absence of complex solar tracking equipment. Low temperature STEs operate within temperatures ranges below 300oC. This research work is geared towards developing feasible low temperature STE conversion technology for electrical power generation. Preliminary small-scale concept plants have been designed at 500Wp and 10KWp. Mathematical models of the plant systems have been developed and simulated on the EES (Engineering Equation Solver) platform. Fourteen candidate working fluids and three cycle configurations have been analysed with the models. The analyses included a logic model selector through which an optimal conversion cycle configuration and working fluid mix was established. This was followed by detailed plant component modelling; the detailed component model for the solar field was completed and was based on 2-dimensional segmented thermal network, heat transfer and thermo fluid dynamics analyses. Input data such as solar insolation, ambient temperature and wind speed were obtained from the national meteorology databases. Detailed models of the other cycle components are to follow in next stage of the research. This paper presents findings of the system and solar field component.

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