Author: Patrick Elie Kattan
Publisher:
ISBN:
Category :
Languages : en
Pages : 258
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Book Description
In this thesis, a new model of under-floor heating systems is developed and validated with published data; the model represents a compromise between the accuracy and the complexity of other models found in the literature, and could be used for transient simulations under several control strategies. In addition, a study is conducted to compare the energy efficiency of under-floor and convective heating systems under equal indoor comfort levels and air quality, for the four climatic zones of Lebanon; the results show that the radiant systems provide 26% reduction in the peak demand, and 30% reduction in the energy consumption. Moreover, an integrated solar/diesel heating system is proposed as the energy source, and design charts are developed for the sizing of the solar system. The solar panels area is then optimized based on a cost analysis in order to minimize the total cost of the system over its life time. Finally, two case studies are conducted for Beirut and Cedars; it was found that the integrated system will pay-back in 12 years in Beirut and in 7 years in Cedars.
Author: Xiangyu Cai
Publisher:
ISBN:
Category :
Languages : en
Pages :
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A dynamic model of a solar-assisted hydronic space heating system for a multi-function building has been developed. The system performance under different control strategies and the model-based energy simulations studies have been conducted. The system consists of several components including a boiler, heat exchangers, flat-plate solar collectors, a water storage tank, baseboard heaters and a radiant floor heating system. The model consists of nonlinear differential equations which were programmed and solved using the MATLAB software. Two control strategies have been explored to compare the system performance: (i) a conventional PI control and (ii) a gain-scheduling adaptive (GSA) PI control. The simulation results indicate that the system performance under GSA PI control is better than the conventional PI control with respect to disturbance rejection and stability. An optimization problem was formulated and solved to study the energy performance of the system. Preliminary simulation results with assumed outdoor temperature profiles showed that the optimized set-point operating strategy contributes 7% and 14.87% to boiler energy saving in mild and warm day conditions compared with constant set-point strategy. One week energy simulations under actual weather conditions based on typical meteorological year (TMY) data have been conducted to investigate the percent contribution of solar energy to space heating. The simulation results show that the solar system contributes less energy during cold winter conditions such as in the month of December. However, it can reduce 16.94% of boiler energy supplied to the radiant floor heating system in the month of March. Besides, the implementation of the optimal GSA PI control strategy can result in higher solar fractions of 5.71% and 30.36% as compared to the base case PI control under cold (December) and mild (March) weather conditions, respectively.
Author: Abdulla Sousi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
This study explores the economic feasibility of the underfloor heating system in North Cyprus. A case study of typical residential apartment 150m to compare the annual cost savings during the winter season between first the apartment depending only on split unit and second use solar energy to heat the underfloor. The initial investment or new life cycle investments are 10000TL with 4 solar collector units. The solar energy is cost effective, therefore as a result of the comparison the annual cost savings were 3260TL.The Solar panels which were used to collect 33.88kWh/day of energy. The feasibility of this study was determined by criteria like Net Present Value NPV, Simple Payback period SPB, Savings-to-Investment Ratio SIR, Internal Rate of Return IRR. NPV which was obtained greater than zero, IRR percentage was larger than the discount rate. The utilize of solar energy reduced the electricity cost and energy consumption.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 64
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Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 64
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Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author: Zhuanglin Zhang
Publisher:
ISBN:
Category : Hot-water heating
Languages : en
Pages : 58
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Book Description
Author: David M. Joncich
Publisher:
ISBN:
Category : Solar heating
Languages : en
Pages : 26
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Book Description
This report describes the performance of a residential-scale, completely instrumented solar heating system located at the U.S. Army Construction Engineering Research Laboratory (CERL), Champaign, IL. The investigation was made between January 1977 and April 1978. In addition, a daily profile of the performance of the system and its components is presented for a representative sunny winter day. An analysis of the solar system operation indicated that the collector array is by far the most inefficient component in the system for converting incident solar energy into useful heat. The solar system consists of 20 sq m (220 sq ft) of flat-plate, selective surface, singly glazed solar collerctors and a 7.6 cu m (2000 gal) equivalent hot water storage tank. The storage system supplies hot water for heating a 50 sq m (540 sq ft) building used by CERL as office space. There is no domestic hot water in the building. Auxiliary energy is supplied by an electric, flow-through hot water heater. The results of this research are presented in terms of mean daily averages for each month during the heating season and include instantaneous solar radiation (horizontal and in the plane of the collector), useful heat acquired by the collector, useful heat delivered to the thermal storage tank, useful heat delivered to the heating load, thermal storage heat losses, and electrical energy supplied to the pumps. (Author).
Author: United Nations Development Programme
Publisher:
ISBN:
Category : Solar water heaters
Languages : en
Pages : 55
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Book Description
Author: Mohammad Yousef Mousa Naser
Publisher:
ISBN:
Category : Computational fluid dynamics
Languages : en
Pages : 99
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Book Description
Space heating is required in almost every dwelling across the country for different periods of time. The thermal energy needed to meet a heating demand can be supplied using different conventional and/or renewable technologies. Solar energy is one example of a renewable resource that can be used for supplying heating needs. It can be utilized either by using photovoltaic panels to generate electricity, that in turn can be used to operate heaters, or by using solar thermal panels. Solar thermal panels obtain higher operating efficiencies than photovoltaic panels, but solar energy for heating purposes suffers from a mismatch between supply and demand. This problem can be solved by employing large tanks that serve as seasonal thermal energy storage units. This work focuses on assessing the performance of solar thermal panels in supplying the space heating needs of a single-family dwelling in two different cities in the United States. These panels are coupled to a cylindrical tank buried in the ground for seasonal and daily energy storage, and a heat exchanger to transfer heat to the home. Storage tank size, collector area, and the working fluid mass flow rate are investigated to determine adequate values for these parameters to enhance the overall system performance. In addition, the simulation timestep for the program and the spatial grid sizes used in the CFD (computational fluid dynamics simulation) model of the storage unit have been examined to determine values of each to keep the simulation time reasonable without substantial loss in accuracy. These results are obtained by mathematically modeling the system components, the solar thermal panels, the heat exchanger, and the storage tank; then programming this mathematical model in MATLAB. Parts of the developed computer code were obtained from previous work and have been modified to suit the purpose of this project. Flat plate solar panels have been chosen for use as the solar collectors. An unmixed, crossflow heat exchanger is considered for transferring the thermal energy from the glycol-water mixture in the collectors to the air in the house. The storage unit CFD simulation is composed of the tank, insulation, and ground surrounding the tank and is based on the SIMPLE algorithm developed by Patankar.
Author: National Intelligence Council
Publisher: Cosimo Reports
ISBN: 9781646794973
Category :
Languages : en
Pages : 158
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Book Description
"The ongoing COVID-19 pandemic marks the most significant, singular global disruption since World War II, with health, economic, political, and security implications that will ripple for years to come." -Global Trends 2040 (2021) Global Trends 2040-A More Contested World (2021), released by the US National Intelligence Council, is the latest report in its series of reports starting in 1997 about megatrends and the world's future. This report, strongly influenced by the COVID-19 pandemic, paints a bleak picture of the future and describes a contested, fragmented and turbulent world. It specifically discusses the four main trends that will shape tomorrow's world: - Demographics-by 2040, 1.4 billion people will be added mostly in Africa and South Asia. - Economics-increased government debt and concentrated economic power will escalate problems for the poor and middleclass. - Climate-a hotter world will increase water, food, and health insecurity. - Technology-the emergence of new technologies could both solve and cause problems for human life. Students of trends, policymakers, entrepreneurs, academics, journalists and anyone eager for a glimpse into the next decades, will find this report, with colored graphs, essential reading.
