scholarly journals PERFORMANCE OPTIMIZATION OF PHASE CHANGE HEAT ACCUMULATOR WITH TURN-OVER TRIANGULAR TUBE

2021 ◽  
Vol 16 ◽  
Author(s):  
Ming Zhao ◽  
Yuhao Zheng
Keyword(s):  
Phase Change ◽  
Performance Optimization ◽  
Heat Accumulator ◽  
Turn Over

Numerical modeling of an optimal heat accumulator with phase change

1991 ◽  
Vol 61 (5) ◽  
pp. 1345-1350 ◽  
Author(s):  
O. V. Dikhtievskii ◽  
G. V. Konyukhov ◽  
O. G. Martynenko ◽  
I. F. Yurevich
Keyword(s):  
Numerical Modeling ◽  
Phase Change ◽  
Heat Accumulator ◽  
Optimal Heat

Thermal Performance Optimization of Shape Stabilized Phase Change Material Used in Building Envelopes

2017 ◽  
Vol 744 ◽  
pp. 201-206
Author(s):  
Yin Zhang ◽  
Ming Shan Zhang
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Performance Optimization ◽  
Optimization Design ◽  
Phase Change Materials ◽  
Transfer Model ◽  
Building Envelopes ◽  
Practical Applications ◽  
Indoor Thermal Comfort ◽  
Heating Loads

Integrating phase change materials (PCM) with building envelopes is an effective way to reduce the cooling or heating loads, improve indoor thermal comfort and save building energy consumptions. In this paper, the heat transfer model of building envelopes with shape stabilized PCM is established and the optimal phase change temperature and enthalpy of PCM for internal walls are determined. Moreover, different PCM locations in external walls are compared based on the evaluation index of integrated uncomfortable degree. The results shows that to improve indoor thermal comfort, it is preferable to put the PCM in the middle of external wall. It also indicates that the overall integrated uncomfortable degree in a whole year decreases with increasing thickness of the inserted shape stabilized PCM plate. This work is of great significance in guiding the optimization design of building envelopes with PCM for practical applications.

A Methodology of an Automotive Engine Cooling Using a Phase Change Material

2009 ◽  
Author(s):  
Kibum Kim ◽  
Kyung-wook Choi ◽  
Ki-hyung Lee ◽  
Kwan-soo Lee
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Load ◽  
Cooling System ◽  
Heat Accumulator ◽  
Full Size ◽  
Automotive Engine ◽  
Excessive Heat ◽  
Engine Cooling ◽  
Change Material

The size of a cooling inventory is generally designed based on which size can endure the excessive heat load situations that occur sporadically. As a result, cooling systems are often too large for most normal driving modes. There have been numerous efforts to downsize the automotive engine cooling system using novel concepts and strategies (e.g. THEMIS cooling system, CoolMaster, UltimateCooling). However, in terms of the system design, preserving the passive cooling strategy may be simpler and more practical than implementing any major changes. Vetrovec (2008) proposed the use of a heat accumulator that has a phase change material (PCM) within the automotive cooling system. Excessive heat generated during severe operating conditions is stored in the heat accumulator, and it is dissipated during periods of low heat load. The heat dissipation capacity of the radiator and the amount of coolant in the cooling system are normally designed such that the system can sustain itself at peak heat load during acceleration and hill ascents in hot summer periods. Therefore, the unnecessarily large cooling inventory creates an overloaded vehicle which increases the fuel consumption rate. A heat accumulator which averages out the peak heat loads can reduce the entire cooling system remarkably in terms of both its volume and weight. Effective cooling in automobiles is beneficial in reducing harmful emissions as well as improving fuel economy. A simulation was conducted to validate the feasibility of using a novel cooling strategy that utilized the heat load averaging capabilities of a phase change material (PCM). Three prototypes were designed: full size, down sized, and a down sized prototype with a heat accumulator containing the PCM inside. When the full size of the cooling inventory was downsized by 30%, this smaller design failed to dissipate the peak heat load and consequently led to a significant increase in the coolant temperature, around 25 °C greater than that in the full size system. However, the peak heat load was successfully averaged out in the downsized system with a heat accumulator. Experimental study is also on-going to validate the simulation results and find more suitable PCM for the application.

scholarly journals The Impact of a Mobile Shading System and a Phase-Change Heat Store on the Thermal Functioning of a Transparent Building Partition

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2512
Author(s):  
Michał Musiał ◽  
Lech Lichołai
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Climatic Conditions ◽  
Temperate Climate ◽  
Summer Period ◽  
Heat Accumulator ◽  
Climate Conditions ◽  
Empirical Results ◽  
The Impact ◽  
Change Material

The article presents the results of multi-month field tests and numerical analyses describing the thermal functioning of mobile shading systems for building windows containing a phase-change heat accumulator. The experiments were conducted in the summer period with temperate climate conditions in Rzeszów (Poland). The tested shading system was dedicated to the daily life cycle of residents, taking into account both the need to illuminate the rooms with natural light and reducing the undesirable overheating of the rooms in the summer. The obtained empirical results showed a reduction in room overheating in the summer period by 29.4% from composite windows with a phase-change heat accumulator and a mobile shading system as compared to the reference composite window with an analogous mobile shading system. The database of empirical results allowed for the creation and verification of a numerical model of heat conversion, storage and distribution within the composite window containing phase change material and a mobile shading system. The verified model made it possible to analyse the thermal functioning of the modified transparent partitions in cool temperate, temperate and subtropical climates. The article is a solution to the problem of undesirable overheating of transparent building partitions by efficient storage and distribution of solar radiation energy thanks to the use of a mobile shading system and a phase change material, while presenting a useful tool enabling the prediction of energy gains in different climatic conditions.

Performance Optimization of Thermal Energy Storage Based Solar Collector

2021 ◽  
Author(s):  
Vivek R. Pawar ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Energy Storage ◽  
Phase I ◽  
Phase Change ◽  
Heat Pipe ◽  
Phase Ii ◽  
Performance Optimization ◽  
Solar Collector ◽  
Phase Change Materials ◽  
Normal Operation ◽  
On Demand

Abstract The application of solar collectors in water heating systems has attracted attention in recent years, however, due to the inconsistency of solar radiation, performance of such systems will fluctuate over time. In this study, performance optimization of a heat pipe evacuated tube solar collector integrated with phase change materials (PCMs), is investigated under normal and on-demand operations. In phase-I, the effect of heat pipe position and in phase-II, the effect of various PCMs are investigated. The results from phase-I show phase change process of PCM was expedited by 48 minutes under on-demand operation compared with conventional system. Additionally, in normal operation, thermal storage enhancement is achieved by 24% increase in PCM’s melting fraction. In Phase-II, the selected PCMs are tritriacontane paraffin, xylitol, and erythritol. In normal mode, the paraffin tube exhibited highest total energy storage of 295.39 kJ/kg, however, the fin temperature of xylitol tube was around 10° C higher compared with the other tubes throughout the day. In on-demand operation, erythritol tube shows energy storage of 413.15 kJ/kg, however, the paraffin tube shows fin temperature difference of 14°C compared with other tubes. Consequently, utilization of paraffin/xylitol in normal and paraffin/erythritol in on-demand operation is recommended to enhance system’s thermal performance.

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