Design of a Packed Bed Thermal Storage Unit for a Solar System

1982 ◽  
Vol 104 (3) ◽  
pp. 223-228 ◽  
Author(s):  
B. T. Kulakowski ◽  
F. W. Schmidt
Keyword(s):  
Pressure Drop ◽  
Solar System ◽  
Heat Storage ◽  
Geographical Location ◽  
Thermal Storage ◽  
Heating System ◽  
Packed Bed ◽  
Fluid Temperature ◽  
Storage Unit ◽  
State College

A method for the design and sizing of a packed bed thermal storage unit for a hot air solar heating system is presented. A controlled bypass of the heat storage unit during the retrieval process is used in order to maintain the fluid temperature leaving the system at a constant value. The use of a bypass arrangement with a closed air circulation loop for the collector enables the storage unit to operate at a higher mean temperature and the system to utilize the maximum allowable pressure drop. This results in a greater heat storage per unit volume of storage material. The complete solar system is simulated numerically during both the heating and retrieval modes of operation to obtain a set of design charts for sizing the thermal storage unit. In the simulation, consideration is given to geographical location, composition of the storage bed and the maximum allowable pressure drop across the bed. A set of design curves for State College, Pennsylvania, is presented.

scholarly journals A Domestic Solar/Heat Pump Heating System Incorporating Latent and Stratified Thermal Storage

2008 ◽  
Author(s):  
Christoph Trinkl ◽  
Wilfried Zo¨rner ◽  
Vic Hanby
Keyword(s):  
Latent Heat ◽  
Heat Pump ◽  
Solar Collector ◽  
Energy Demand ◽  
Heat Storage ◽  
Thermal Storage ◽  
Heating System ◽  
System Control ◽  
Latent Heat Storage ◽  
Solar Heat

Both solar and heat pump heating systems are innovative technologies for sustaining ecological heat generation. They are gaining more and more importance due to the accelerating pace of climate change and the rising cost of limited fossil resources. Against this background, a heating system combining solar thermal collectors, heat pump, stratified thermal storage and water/ice latent heat storage has been investigated. The major advantages of the proposed solar/heat pump heating system are considered to be its flexible application (suitable for new and existing buildings because of acceptable space demand) as well as the improvement of solar fraction (extended solar collector utilisation time, enhanced collector efficiency), i.e. the reduction of electric energy demand for the heat pump. In order to investigate and optimise the heating system, a dynamic system simulation model was developed. On this basis, a fundamental control strategy was derived for the overall coordination of the heating system with particular regard to the performance of the two storage tanks. In a simulation study, a fundamental investigation of the heating system configuration was carried out and optimisation derived for the system control as well as the selection of components and their dimensioning. The influence of different parameters on the system performance was identified, where the collector area and the latent heat storage volume were found to be the predominant parameters for system dimensioning. For a modern one-family house, a solar collector area of 30m2 and a latent heat store volume of 12.5m3 are proposed. In this configuration, the heating system reaches a seasonal performance factor of 4.6, meaning that 78% of the building’s and users’ heat demand are delivered by solar energy. The results show that the solar/heat pump heating system can give an acceptable performance using up-to-date components in a state-of-the-art building.

Experimental Investigation on a Latent Heat Thermal Storage Unit for Solar Cooling Application

Green ◽  
2011 ◽  
Vol 1 (2) ◽  
Author(s):  
L. Chidambaram ◽  
A. S. Ramana ◽  
G. Kamaraj ◽  
R. Velraj
Keyword(s):  
Solar Energy ◽  
Latent Heat ◽  
Solar Collector ◽  
Heat Storage ◽  
Storage System ◽  
Thermal Storage ◽  
Environmental Crisis ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
Solar Cooling

AbstractConventional cooling technologies that utilize harmful refrigerants consume more energy and cause peak loads leading to negative environmental impacts. As the world grapples with the energy and environmental crisis, there is an urgent need to develop and promote environmentally benign sustainable cooling technologies. Solar cooling is one such promising technology, given the fact that solar energy is the cheapest and most widely available renewable energy that matches the cooling load requirements. However thermal storage systems are essential to overcome the disadvantage of the intermittent nature of solar energy and variations in the cooling demand. The enhanced utilization of solar energy and other consequences of thermal storage integrated systems have gained the attention of researchers in recent years. The concept of combined sensible and latent heat storage system is successfully introduced in several applications and it has many advantages. This paper presents the performance of the solar collector system and the charging characteristics of a PCM based latent heat thermal storage unit, which is designed to provide continuous supply of heat for the operation of 1 kW vapor absorption refrigeration unit. Investigations on PCM integrated thermal storage system have revealed improvement in heat storage capacity, lower heat loss and an increased solar collector efficiency due to better thermal stratification.

Design Optimization of a Single Fluid, Solid Sensible Heat Storage Unit

1977 ◽  
Vol 99 (2) ◽  
pp. 174-179 ◽  
Author(s):  
F. W. Schmidt ◽  
R. R. Somers ◽  
J. Szego ◽  
D. H. Laananen
Keyword(s):  
Design Optimization ◽  
Heat Storage ◽  
Operating Conditions ◽  
Minimum Length ◽  
Complex Method ◽  
Fluid Temperature ◽  
Sensible Heat ◽  
Storage Material ◽  
Storage Unit ◽  
Flowing Fluid

The optimization of the design of a solid sensible heat storage unit initially at a uniform-temperature is presented. The storage unit is composed of a number of rectangular cross-sectional channels for the flowing fluid, connected in parallel and separated by the heat storage material. The complex method for constrained nonlinear optimization as presented by M. J. Box is utilized, with some modifications. The design optimization is based upon achieving maximum utilization of the heat storage or removal capabilities of the material for a given set of operating conditions. This is achieved by varying the storage unit’s geometry while placing constraints on the maximum and minimum length of the unit, fluid channel size, storage material thickness, maximum and minimum outlet fluid temperature, and the minimum amount of heat to be stored.

scholarly journals Design, Developing and Construction of an Educational Solar Water Heating System with Phase Change

2015 ◽  
Vol 10 (1) ◽  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Solar Collector ◽  
Heat Storage ◽  
Heating System ◽  
Storage Unit ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System ◽  
Change Material

An educational solar water heater with phase change material (PCM) was designed, developed, and constructed for instructional and demonstrative purposes. This interactive solar water heating system experimental apparatus is capable of demonstrating thermal energy storage and heat transfer concepts and principles. The system consists of two simultaneously functioning heat absorbing units. The first is a flat plate solar collector and the other is a heat storage unit consisting of phase change material (paraffin wax). The heat storage unit utilizes small aluminium cylinders (heat exchangers) filled with paraffin wax as the heat storage medium. Water pump is used to circulate the water between the solar collector and the storage unit where the PCM is located. Results indicate that the PCM stored energy, as latent heat, that was absorbed by the solar collector and released to heat the water in the storage tank when half of the hot water was replaced with cold water. Moreover, tests indicated that latent heat storage is more effective than sensible.

Optimization of a Packed Bed Thermal Energy Storage Unit

1987 ◽  
Vol 109 (3) ◽  
pp. 170-175 ◽  
Author(s):  
H. Torab ◽  
D. E. Beasley
Keyword(s):  
Energy Storage ◽  
Cross Section ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Relative Size ◽  
Packed Bed ◽  
Operating Conditions ◽  
Fluid Temperature ◽  
Storage Unit ◽  
Energy Storage Unit

The optimization of the design of a packed-bed thermal energy storage unit is presented. A one-dimensional, transient, two-phase model is chosen for the packed bed which assumes uniformity at each cross section within the packing. The governing equations for the time dependent temperature distributions in both the solid and fluid phases are solved using a fully implicit formulation. The accuracy of the numerical method is demonstrated by comparison with experimental measurements of temperature distribution in a randomly packed bed of uniform spheres. The goal of the optimization is to achieve maximum utilization of the thermal energy storage and recovery capabilities of the storage medium for a given set of operating conditions. The optimum combination of bed length, size of the packing particles, and relative size of the bed cross section to the particle diameter is determined, subject to constraints on the maximum allowable pressure drop across the packing, the maximum outlet fluid temperature, and the total amount of supplied energy. The thermodynamic availability is examined as the measure of storage utilization. The monotinicity method is utilized for the optimization process. This method identifies a global optimum without any special computations, and prevents acceptance of false optimum solutions, as could be generated by numerical techniques. The results of the study provide guidelines for choosing the size of the packing and the packing particle subject to the constraints for a practical operating system.

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