Temperature stratification in hot water solar thermal storage tanks

1981 ◽  
Author(s):  
S. KOLDHEKAR
Keyword(s):  
Thermal Storage ◽  
Hot Water ◽  
Solar Thermal ◽  
Temperature Stratification ◽  
Storage Tanks

Temperature stratification in hot-water storage tanks

Energy ◽  
1991 ◽  
Vol 16 (7) ◽  
pp. 977-982 ◽  
Author(s):  
K. Hariharan ◽  
K. Badrinarayana ◽  
S. Srinivasa Murthy ◽  
M.V. Krishna Murthy
Keyword(s):  
Water Storage ◽  
Hot Water ◽  
Temperature Stratification ◽  
Storage Tanks

Transient Natural Convection in Enclosures With Application to Solar Thermal Storage Tanks

1992 ◽  
Vol 114 (3) ◽  
pp. 175-181 ◽  
Author(s):  
D. T. Reindl ◽  
W. A. Beckman ◽  
J. W. Mitchell
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchangers ◽  
Thermal Storage ◽  
Solar Thermal ◽  
Storage Tanks ◽  
Time Duration ◽  
Source Temperature ◽  
Fluid Field ◽  
Isothermal Fluid

Many previously studied natural convection enclosure problems in the literature have the bounding walls of the enclosure responsible for driving the flow. A number of relevant applications contain sources within the enclosure which drive the fluid flow and heat transfer. The motivation for this work is found in solar thermal storage tanks with immersed coil heat exchangers. The heat exchangers provide a means to charge and discharge the thermal energy in the tank. The enclosure is cylindrical and well insulated. Initially the interior fluid is isothermal and quiescent. At time zero, a step change in the source temperature begins to influence the flow. The final condition is a quiescent isothermal fluid field at the source temperature. The governing time-dependent Navier-Stokes and energy equations for this configuration are solved by a finite element method. Solutions are obtained for 103≤RaD≤106. Scale analysis is used to obtain time duration estimates of three distinct heat transfer regimes. The transient heat transfer during these regimes are compared with limiting cases. Correlations are presented for the three regimes.

New Solar Thermal Storage Concept – Combined Hot Water and Sorption Store

2010 ◽  
Author(s):  
Rebecca Weber ◽  
Henner Kerskes ◽  
Harald Drück ◽  
Hans Müller-Steinhagen
Keyword(s):  
Thermal Storage ◽  
Hot Water ◽  
Solar Thermal

Integrating Domestic Air Conditioner with Solar Water Heater of the Development of an Energy-Saving Heating System

2015 ◽  
Vol 764-765 ◽  
pp. 1100-1103
Author(s):  
Wen Lih Chen ◽  
King Leung Wong ◽  
Yung Chang Li
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Thermal Storage ◽  
Heating System ◽  
Hot Water ◽  
Air Conditioner ◽  
Storage Tanks ◽  
Air Conditioners ◽  
Solar Water ◽  
Exhaust Heat

The current thesis proposed the integration of air conditioners that exhaust heat with solar energy to enhance the overall efficiency of thermal energy conversion. The analysis of thermal storage tanks of different volumes revealed that a two-ton air conditioner operating for an hour produced double energy than normal sunshine for a day. With thermal storage tanks of fixed volume, the integration of air conditioners of different tons with solar energy indicated that air conditioners of less tons produced faster and more efficient energy conversion. Therefore, the current thesis proposed that the modification of condenser in domestic air conditioner into water-cooled condenser not only enhanced the energy efficiency of air conditioners but also increased hot water supplies since hot water from air conditioners could be integrated into solar water heaters. By doing so, energy conservation and carbon reduction could be achieved.

scholarly journals Fabrication and Performance Evaluation of Cold Thermal Energy Storage Tanks Operating in Water Chiller Air Conditioning System

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4159
Author(s):  
Xuan Vien Nguyen
Keyword(s):  
Heat Transfer ◽  
Cold Storage ◽  
Storage Tank ◽  
Air Conditioning ◽  
Thermal Storage ◽  
Hot Water ◽  
Operating Costs ◽  
Heat Transfer Fluid ◽  
Storage Tanks ◽  
Air Conditioning System

In this study, cold and thermal storage systems were designed and manufactured to operate in combination with the water chiller air-conditioning system of 105.5 kW capacity, with the aim of reducing operating costs and maximizing energy efficiency. The cold storage tank used a mixture of water and 10 wt.% glycerin as a phase-change material (PCM), while water was used as heat transfer fluid (HTF). The cold storage heat exchanger was made of polyvinyl chloride (PVC). On the other hand, the thermal storage tank used water as the storage fluid with a capacity of 50 L of hot water per hour. The thermal storage did not use a pump for water transfer through the heat exchanger, so as to save energy and operating costs. In this paper, the operating parameters of the cold and thermal storage tanks are shown according to the results of experimental research, including the temperatures of cooling and heating load, heat transfer fluid, and cold storage material during the discharge process, as well as the discharge duration. The system assisted the air conditioner in cooling the internship workshop space at the university with an area of 400 m2, contributing to a remarkable reduction in air-conditioning system operating costs during the daytime. Furthermore, the system recovered waste heat from the compressor of the water chiller, and a thermal storage system was successfully built and operated, providing 50 L of hot water at a temperature of 60 °C per hour to serve the everyday needs of school students. This design was suitable for the joint operation of cold and thermal storage tanks and the water chiller air-conditioning system for cooling and heating applications.

Effect of Shroud and Baffle on Heat Transfer in a Solar Thermal Storage Tank

2009 ◽  
Author(s):  
S. K. S. Boetcher ◽  
F. A. Kulacki
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Transfer Rate ◽  
Thermal Storage ◽  
Solar Thermal ◽  
Discharge Process ◽  
Storage Tanks ◽  
Nusselt Numbers ◽  
Enhancing Heat Transfer ◽  
Rayleigh Numbers

Enhancing heat transfer during the charge and discharge of solar thermal storage tanks is an ongoing technical challenge. The types of thermal storage systems considered in the present study comprise an immersed heat exchanger at the top of a solar thermal storage fluid. The discharge process of a thermal store with specified dimensions is numerically simulated over a range of Rayleigh numbers, 105 < RaD <107. The immersed heat exchanger is modeled as a two-dimensional isothermal cylinder which is situated near the top of a water-filled tank with adiabatic walls. An adiabatic shroud whose shape is parametrically varied is placed around the cylinder. In addition, the shroud is connected to an adiabatic baffle situated beneath the cylinder. Nusselt numbers are calculated for different shroud shapes at different Rayleigh numbers. Results show that the shroud is effective in increasing the heat transfer rate. Optimal shroud and baffle geometries are presented as well as qualitative flow results.

Diffuser design influence on the performance of solar thermal storage tanks

1991 ◽  
Vol 15 (7) ◽  
pp. 525-534 ◽  
Author(s):  
A. Al-Maraffie ◽  
A. Al-Kandari ◽  
N. Ghaddar
Keyword(s):  
Thermal Storage ◽  
Solar Thermal ◽  
Storage Tanks
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