scholarly journals Geometrically activated thermal mass: wood vs. concrete

2021 ◽  
Vol 2042 (1) ◽  
pp. 012156
Author(s):  
Remy Fortin ◽  
Salmaan Craig
Keyword(s):  
Heat Transfer ◽  
Heat Storage ◽  
Thermal Mass ◽  
Convection Coefficient ◽  
Wall Area ◽  
Carbon Neutrality ◽  
Climate Resilience ◽  
Low Emission ◽  
Building Level ◽  
Surface Convection

Abstract Designing for climate resilience and carbon neutrality implies low-emission structures that double as thermal mass. In this study, the effect of using geometry to maximize natural surface convection on an internal thermal mass is investigated. Wood and concrete thermal masses are optimized for both instantaneous heat transfer and transient heat storage, and compared. It is found that the addition of optimally-sized fins can double or triple the convection coefficient at the interior surface, provided the thermal conductivity of the fins is sufficiently high. Doubling or tripling the surface heat transfer translates to an equivalent increase in dynamic energy storage, so long as the mass thickness, wall area, and vent openings are recalibrated to maintain thermal synchrony at the building-level.

Interrelation between glazing and summer operative temperature in buildings

2016 ◽  
Vol 7 (1) ◽  
pp. 51-60 ◽  
Author(s):  
F. Kalmár
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Mass ◽  
Operative Temperature ◽  
Energy Demands ◽  
Low Emission ◽  
Building Facades ◽  
Window Area ◽  
Positive Effect

Nowadays large transparent surfaces are widely used in office and public buildings. The positive effect of great views and natural light on people’s comfort is well known, but the high glazed ratio of building facades can lead to excessively high cooling energy demands. The heat load can be reduced by using glazing with high reflexion coating outwards and low emission coating inwards, triple panes and inert gas between the panes. Choosing proper thermal mass can further help in reducing the amplitude of the indoor operative temperature. In this paper the effects of solar factor of glazing, heat transfer coefficient of windows, windows area and thermal mass were analysed in an imaginary room with 3.0×4.0×2.8 m dimensions. As the results show the effect of the overall heat transfer coefficient is negligible. The effect of solar factor depends on the orientation. The expected differences between the amplitudes of the operative temperature are between 0.5 to 6 K for the analyzed room, depending on the thermal mass, orientation, solar factor and window area.

Maximizing Heat Transfer Through Joint Fin Systems

2005 ◽  
Vol 128 (2) ◽  
pp. 203-206 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Performance ◽  
Critical Length ◽  
The Other ◽  
Rigid Fixation ◽  
Convection Coefficient ◽  
Heat Transfer Characteristics ◽  
Cold Side ◽  
Transfer Characteristics

Heat transfer through joint fins is modeled and analyzed analytically in this work. The terminology “joint fin systems” is used to refer to extending surfaces that are exposed to two different convective media from its both ends. It is found that heat transfer through joint fins is maximized at certain critical lengths of each portion (the receiver fin portion which faces the hot side and the sender fin portion that faces the cold side of the convective media). The critical length of each portion of joint fins is increased as the convection coefficient of the other fin portion increases. At a certain value of the thermal conductivity of the sender fin portion, the critical length for the receiver fin portion may be reduced while heat transfer is maximized. This value depends on the convection coefficient for both fin portions. Thermal performance of joint fins is increased as both thermal conductivity of the sender fin portion or its convection coefficient increases. This work shows that the design of machine components such as bolts, screws, and others can be improved to achieve favorable heat transfer characteristics in addition to its main functions such as rigid fixation properties.

scholarly journals The Impact of Active and Passive Thermal Management on the Energy Storage Efficiency of Metal Hydride Pairs Based Heat Storage

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3006
Author(s):  
Serge Nyallang Nyamsi ◽  
Ivan Tolj
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Management ◽  
Metal Hydride ◽  
Heat Storage ◽  
Energy Storage Density ◽  
Storage Efficiency ◽  
Transfer Enhancement ◽  
Storage Density ◽  
Energy Storage Efficiency

Two-tank metal hydride pairs have gained tremendous interest in thermal energy storage systems for concentrating solar power plants or industrial waste heat recovery. Generally, the system’s performance depends on selecting and matching the metal hydride pairs and the thermal management adopted. In this study, the 2D mathematical modeling used to investigate the heat storage system’s performance under different thermal management techniques, including active and passive heat transfer techniques, is analyzed and discussed in detail. The change in the energy storage density, the specific power output, and the energy storage efficiency is studied under different heat transfer measures applied to the two tanks. The results showed that there is a trade-off between the energy storage density and the energy storage efficiency. The adoption of active heat transfer enhancement (convective heat transfer enhancement) leads to a high energy storage density of 670 MJ m−3 (close to the maximum theoretical value of 755.3 MJ m−3). In contrast, the energy storage efficiency decreases dramatically due to the increase in the pumping power. On the other hand, passive heat transfer techniques using the bed’s thermal conductivity enhancers provide a balance between the energy storage density (578 MJ m−3) and the energy efficiency (74%). The utilization of phase change material as an internal heat recovery medium leads to a further reduction in the heat storage performance indicators (142 MJ m−3 and 49%). Nevertheless, such a system combining thermochemical and latent heat storage, if properly optimized, can be promising for thermal energy storage applications.

Solid Media Thermal Storage Development and Analysis of Modular Storage Operation Concepts for Parabolic Trough Power Plants

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Doerte Laing ◽  
Wolf-Dieter Steinmann ◽  
Michael Fiß ◽  
Rainer Tamme ◽  
Thomas Brand ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Heat Storage ◽  
Storage Systems ◽  
Storage System ◽  
Sensible Heat ◽  
Economic Optimization ◽  
Parabolic Trough ◽  
Solid Media ◽  
Exergetic Analysis

Cost-effective integrated storage systems are important components for the accelerated market penetration of solarthermal power plants. Besides extended utilization of the power block, the main benefits of storage systems are improved efficiency of components, and facilitated integration into the electrical grids. For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option in terms of investment and maintenance costs. For commercial oil trough technology, a solid media sensible heat storage system was developed and tested. One focus of the project was the cost reduction of the heat exchanger; the second focus lies in the energetic and exergetic analysis of modular storage operation concepts, including a cost assessment of these concepts. The results show that technically there are various interesting ways to improve storage performance. However, these efforts do not improve the economical aspect. Therefore, the tube register with straight parallel tubes without additional structures to enhance heat transfer has been identified as the best option concerning manufacturing aspects and investment costs. The results of the energetic and exergetic analysis of modular storage integration and operation concepts show a significant potential for economic optimization. An increase of more than 100% in storage capacity or a reduction of more than a factor of 2 in storage size and therefore investment cost for the storage system was calculated. A complete economical analysis, including the additional costs for this concept on the solar field piping and control, still has to be performed.

Sign in / Sign up

Export Citation Format

Share Document