A Second Law Approach to Characterising Thermally Stratified Hot Water Storage With Application to Solar Water Heaters

1999 ◽  
Vol 121 (4) ◽  
pp. 194-200 ◽  
Author(s):  
G. Rosengarten ◽  
G. Morrison ◽  
M. Behnia
Keyword(s):  
Temperature Distribution ◽  
Heat Exchangers ◽  
Water Storage ◽  
Heating System ◽  
Hot Water ◽  
Effect Of Temperature ◽  
Storage Efficiency ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water

This paper presents a method of characterising and evaluating the performance of hot water storage systems in terms of their temperature distribution. The change in exergy from the stratified state to the delivery state depends on the stored energy and the stratification. It can thus he used to define the storage efficiency for sensible heat storage devices. A new parameter that isolates the stratification component of the exergy is defined and called the stratification efficiency. The effect of temperature distribution, delivery temperature and tank cross-section on exergy and stratification efficiency is investigated. The advantage that stratification offers over a mixed tank is examined in terms of the storage efficiency and overall solar water heating system performance. Exergy is used to assess the operation of mantle heat exchangers in solar water heating systems and it is shown that exergy and stratification efficiency, as well as energy, should be used to ascertain the performance of such heat exchangers.

scholarly journals Economic assessment and optimizing of the solar water heating system

2018 ◽  
Vol 210 ◽  
pp. 02023
Author(s):  
Jan Skovajsa ◽  
Martin Zálešák
Keyword(s):  
Solar System ◽  
Optimal Solution ◽  
Heating System ◽  
Hot Water ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

The article deals with the economic evaluation of investment and optimization of the solar water heating system for family houses. From the point of view of solar systems, the optimal solution is based on the specific application of it. The design is dependent on the location of solar thermal collectors and ration between active aperture area and real daytime consumption. Common calculations according to actual standards often give overstated results, which also reflected in the value of the investments. The article presents the research of optimal parameters of the thermal solar system for preparing of domestic hot water. A combination of related standards and software TRNSYS are used to find optimal parameters. Thanks to created and verified simulation models, it is possible to design parameters so as to avoid under-dimensioning or over-dimensioning of the solar system. Energy price is another factor affects the payback period of investments. This is affected by the used energy sources and their combination. For example, buildings that use electricity to heat water or heating have different energy charges than a building that uses natural gas. So, the aim is to find technically and economically efficient solution.

Joint Application of Solar Water Heating System and Air-Conditioning System in a Dormitory Building

2010 ◽  
Vol 171-172 ◽  
pp. 215-218
Author(s):  
Hai Ying Wang ◽  
Song Tao Hu ◽  
Jia Ping Liu
Keyword(s):  
Air Conditioning ◽  
Heating System ◽  
Hot Water ◽  
Water Tank ◽  
Auxiliary Heating ◽  
Water Heating ◽  
Air Conditioning System ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

Solar water heating system is used to supply hot water all-year-round for a new dormitory building. Flat solar energy collectors are mounted on the roof. The hot water tank and pumps are installed together with the air conditioning equipments in the plant room. Air cooled heat pump is used to provide cooling in summer, and high temperature water from boiler room (in old building) is used as heat source in winter. Usually auxiliary heating is necessary to improve the stability and reliability of solar water heating system. In this case, we take full use of the equipment of air conditioning system instead of electricity as auxiliary heating resources. In this paper, we introduced the design of the solar water heating system and the auxiliary heating method by air conditioning systems. The control strategies to fulfill all the functions and switch between different conditions are also introduced.

Experimental Research on a Novel Solar Water Heating System by Using Loop Heat Pipe

2013 ◽  
Vol 724-725 ◽  
pp. 163-170
Author(s):  
Zhang Yuan Wang ◽  
Xiang Mei Zhang ◽  
Wan Sheng Yang ◽  
Zhi Wu Chen
Keyword(s):  
Heat Pipe ◽  
High Efficiency ◽  
Heating System ◽  
Hot Water ◽  
Loop Heat Pipe ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Evacuated Tubes ◽  
Solar Water Heating System

In this paper, a novel solar water heating system will be proposed by applying the loop heat pipe to a conventional split solar hot water system, which will have the characteristics of high efficiency, low cost, appearance appealing and building integration. Three types of the system, i.e., the system with evacuated tubes, with single flat-plate glazing cover, and without glazing, will be experimentally investigated and compared on the influence to the dynamic performance of the system. It was found that the system’s operating temperature increased significantly during the start-up stage and gently after until reach relatively constant. The instantaneous efficiency was found to be fluctuated, although it reached stable eventually during the operations for all three types. By using the moving average calculating method, every 10 minutes were applied for the calculation of the average efficiency which had a negative linear relation with the combined factor of (Tmean-Tamb)/I. In general, the solar system with evacuated tubes performed the best with the highest water temperature output, highest system efficiency and lowest heat loss coefficient among the three systems.

scholarly journals Performance Studies and Energy-Saving Analysis of a Solar Water-Heating System

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1536
Author(s):  
Xilian Han ◽  
Chao Li ◽  
Hongqiang Ma
Keyword(s):  
Solar Energy ◽  
Energy Saving ◽  
Large Scale ◽  
Collection Efficiency ◽  
Heating System ◽  
Hot Water ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

This paper proposed an experimental test: the solar water-heating system was been monitored for a whole year to analyze collector performance in an actual operation process. Heat-collecting efficiency, heating capacity, power consumption, and heat required were analyzed theoretically. Results showed that solar irradiance and ambient temperature were positively correlated with heat collection efficiency, and the daily average heat collection efficiency was up to 56.63%. In winter, the auxiliary heat source consumed the most power, almost all of which bears the heat of users. The heat collection in summer met the demand for hot water, and the guarantee rate of solar energy could reach 100%. The energy saving properties and CO2 emission reduction were analyzed. This system had a significant effect on the energy-saving effect and environmental protection. The analysis showed that the hot-water system can fully meet the design requirements under the condition of relatively sufficient solar energy, and can operate stably, which has a certain guiding significance for the design and application of large-scale solar hot-water systems.

Applied Research of Solar Water Heater Integrated with Modern Architecture

2013 ◽  
Vol 756-759 ◽  
pp. 4492-4496
Author(s):  
Bo Yang Zhang ◽  
Ya Hui Xie ◽  
Shun Xiang Sun
Keyword(s):  
Water Storage ◽  
Heating System ◽  
Modern Architecture ◽  
Solar Water Heater ◽  
Storage Tanks ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

This paper describes the application forms of building integrated with solar energy. We explain a solar water heating system; its solar collectors and water storage tanks are placed together. We discuss another solar water heating system, its solar collectors are placed together but its water storage tanks are placed in every resident's home. This paper also introduces the wall-hung SWH and the application of solar refrigeration and solar heating. At last we analyze the problems of the development of solar water heater integrated with modern architecture.

scholarly journals A STEP BY STEP DESIGN GUIDE FOR A SOLAR WATER HEATING SYSTEM CONSIDERING THERMAL LOSSES

2019 ◽  
Vol 18 (2) ◽  
pp. 26
Author(s):  
R. R. Barbosa ◽  
M. Carvalho
Keyword(s):  
Heating System ◽  
Industrial Applications ◽  
Careful Consideration ◽  
Climatic Conditions ◽  
Solar Heating ◽  
Hot Water ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

A clear and direct guide for the design of a solar heating system is presented herein, focused on industrial applications. This guide focuses on the design of solar water heating systems for nonresidential applications. The importance of considering climatic conditions throughout the year is highlighted herein, along with reliable solar radiation data. Solar heating water systems are essential for the diversification of the Brazilian energy matrix and rationalization of the energy resources available. The system is initially dimensioned without the consideration of losses. Then, the required procedure to calculate thermal losses is described, and it is verified that the main losses occur in solar collectors and storage. After careful consideration of the hot water consumption profile and the results obtained in the calculation of the main thermal losses, the storage volume was doubled to guarantee the satisfaction of energy demands.

Test and Research of Solar Water Heating System on High-Rise Residences

2011 ◽  
Vol 224 ◽  
pp. 42-49
Author(s):  
Xiao Hui Du ◽  
Hai Shan Xia ◽  
Zhong Yi
Keyword(s):  
Integrated Design ◽  
Water System ◽  
Weather Conditions ◽  
Heating System ◽  
Hot Water ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
High Rise ◽  
Solar Water Heating System

During the integrated design of solar hot water system into high-rise residences, economy of solar hot water system directly effects its popularization and application. Combining with the concentrated solar water heating system on one high-rise residences, This paper tidies up the testing data on the June to October, and calculates solar insuring rate, auxiliary heat source heating rate and hot water cost at the different weather conditions, analyzes on the causes and provides some improvement advice, which will put forward the reference for architects to make the integrated design on the solar water heating system on high-rise residences.

Hybrid Solar Lighting May Have Another Utility: Solar Water Heating

Solar Energy ◽  
2006 ◽  
Author(s):  
Peter E. Zemke ◽  
Byard D. Wood
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Optical Fibers ◽  
Heating System ◽  
Hot Water ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Lighting ◽  
Solar Water Heating System

Hybrid solar lighting (HSL) has been successfully demonstrated as a means of collecting sunlight and transferring it through optical fibers into a building. The collected solar energy is primarily intended for illumination purposes. However, this technology may have an application in solar water heating. For a traditional solar water heating system, energy is required to pump the water to the roof and collected solar energy is lost to the environment through the collector and plumbing. If such a system is to be used in climates where the temperature falls below freezing, complexity is added resulting in lower system efficiencies. If, rather than pumping water to the roof to absorb solar energy, the solar radiation is “piped” into the hot water store, a solar water heating system may be much less complex and potentially more efficient. HSL technology can be used to collect solar radiation and transport it through optical fibers into a hot water store. Since the water remains in the tank, it is not exposed to freezing temperatures and heat loss through plumbing. The efficiency of the system would not be dependent on the outside temperature or the temperature of the water as traditional systems are, but solely on the efficiency in which solar radiation is transferred into the water. This paper will outline the major advantages of using HSL technology for solar water heating over traditional systems. The approximate efficiencies of a flat-plate collector, 2-axis solar tracking collector, and a system using HSL technology are compared using F-Chart for locations in the Southwestern and Northeastern United States. It is shown that improvements in efficiency are obtained using HSL technology if the system is capable of collecting and transferring the visible and infrared spectrum of solar radiation.

A Photovoltaic Solar Water Heating System

1997 ◽  
Vol 119 (2) ◽  
pp. 126-133 ◽  
Author(s):  
A. H. Fanney ◽  
B. P. Dougherty
Keyword(s):  
Water System ◽  
Heating System ◽  
Water Systems ◽  
Hot Water ◽  
Solar Thermal ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Photovoltaic Array ◽  
Solar Water Heating System

A novel solar water heating system was patented in 1994. This system uses photovoltaic cells to generate electrical energy that is subsequently dissipated in multiple electric resistive heating elements. A microprocessor controller continually selects the appropriate heating elements such that the resistive load causes the photovoltaic array to operate at or near maximum power. Unlike other residential photovoltaic systems, the photovoltaic solar water heating system does not require an inverter to convert the direct current supplied by the photovoltaic array to an alternating current or a battery system for storage. It uses the direct current supplied by the photovoltaic array and the inherent storage capabilities of a residential water heater. A photovoltaic solar hot water system eliminates the components most often associated with the failures of solar thermal hot water systems. Although currently more expensive than a solar thermal hot water system, the continued decline of photovoltaic cell prices is likely to make this system competitive with solar thermal hot water systems within the next decade. This paper describes the system, discusses the advantages and disadvantages relative to solar thermal water heating systems, reviews the various control strategies which have been considered, and presents experimental results for two full-scale prototype systems.

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