Heat transfer characteristics in latent heat storage system using paraffin wax

Jesumathy, Stella P.; Udayakumar, M.; Suresh, S.

doi:10.1007/s12206-011-1017-4

Cited by 71 publications

(16 citation statements)

References 19 publications

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“…Ste numbers between 0.01 and 0.1 (within the realm of common PCMs) were modeled and shown to have little effect on solidification until near the end of the process. Jesumathy et al (2012) investigated a single vertical annulus tube-in-shell design for a PCM-based thermal storage system. Their study showed that the PCM did not melt in a uniform manner; instead, the PCM melted from the top down, even though they had attempted to maintain a constant and uniform thermal bath temperature.…”

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confidence: 99%

Compact PCM-based thermal stores for shifting peak cooling loads

Bourne

Novoselac

2015

Build. Simul.

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Thermal energy stores, when used as part of a demand management system, can shift peak cooling loads to off-peak hours or to periods when intermittent renewable energy sources are available. This enables more efficient use of baseline and renewable electric capacity, and reduces dependence on less efficient and more costly peak energy power plants. High density thermal stores can be an effective retrofit option for existing buildings and environmental control systems. This paper investigates the development of a simple, compact, high density thermal storage unit suitable for use in small to medium residential or commercial applications that utilize, or can be retrofitted to use, chilled water cooling coils. This thermal store design is based on the use of a widely available phase change material (PCM), macro-encapsulated into cylindrical tubes that are packed into a containment tank. An experimental scale model of this thermal store is constructed for test purposes, and tests are conducted to determine the feasibility of this design and to characterize its operation. A numeric model is developed to demonstrate the feasibility of modeling such a store using simplified assumptions, both for design purposes and real-time predictive control strategies. The results show that such a design increases thermal capacity over that of a simple chilled water tank, and that a simplified numeric model for use by control systems can predict the short-term performance of the store in near real-time.

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Section: List Of Symbolsmentioning

confidence: 99%

Compact PCM-based thermal stores for shifting peak cooling loads

Bourne

Novoselac

2015

Build. Simul.

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“…Studies on heat transfer characteristics can provide a theoretical basis for investigations of improving heat transfer rate. Adriano et al, 5 Hosseini et al, 6,7 Avci et al 8 and Jesumathy et al 9 reported researches on the heat transfer mechanism. The findings indicated that in the melting process, heat conduction dominated initially, and then natural convection took over with increasing liquid fraction, whereas the solidification process performed in the opposite order.…”

Section: Introductionmentioning

confidence: 99%

Melting and solidification performance in two horizontal shell‐and‐tube heat exchangers with different structures

et al. 2020

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Recently, a critical problem of latent heat thermal energy storage remains the low thermal conductivity of phase change materials (PCMs), which can lead to low heat transfer rate. Structural optimization design is an effective solution for this problem. In this work, two horizontal shell-and-tube heat exchangers (HEs) with one inner tube (n = 1) and four inner tubes (n = 4) are designed keeping the same amount of PCM and water flow rate, and their melting and solidification thermal performance and heat transfer characteristics are compared. The results show that in comparison with one-inner-tube HE, the temperature of detected points are affected by both upper and lower inner tubes for four-inner-tube HE, thus the differences in phase change process appear. In addition, the phase change time reduction rates are 34.1%, 33.39%, 28.82% at T in (inlet water temperature) = 75 C, 80 C, 85 C during charging process, and 17.2%, 27.69%, 36.67% at T in = 10 C, 15 C, 20 C during discharging process, respectively. In comparison with the one-inner-tube HE, the theoretical efficiency of four-inner-tube HE is increased from 75.88% to 90.34%. Although more friction loss should be paid by four-inner-tube HE, a lower energy consumption and a higher heat-energy ratio are achieved. Based on the results of this study, the amount of cumulative heat per energy consumption is 1.52 × 10 8 and 2.88 × 10 8 for one-inner-tube and four-inner-tube HE, respectively. Highlights • Performance of one-inner-tube and four-inner-tube heat exchanger is compared. • Both melting and solidification processes are taken into consideration. • Thermal interaction between each tube is included for practical value. • Theoretical efficiency increases from 75.88% to 90.34% for the case of n = 4.

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“…The effect of heat transfer fluid velocity and fin spacing is conducted for medium temperature application (paraffin wax) by Ogoh and Groulx [17] in a cylindrical heat storage tank and the fins arranged horizontally. The same paraffin wax material is also utilized the study of heat transfer characteristics by Jesumathy et al [18]. The general objective of this study is to develop a further understanding and modelling of loading process of phase change material (PCM).…”

Section: Introductionmentioning

confidence: 99%

Transient modelling of heat loading of phase change material for energy storage

et al. 2016

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Abstract. As the development of solar energy is getting advance from time to time, the concentration solar technology also get the similar attention from the researchers all around the globe. This technology concentrate a large amount of energy into main spot. To collect all the available energy harvest from the solar panel, a thermal energy storage is required to convert the heat energy to one of the purpose such as electrical energy. With the idea of energy storage application that can be narrow down to commercial application such as cooking stove. Using latent heat type energy storage seem to be appropriate with the usage of phase change material (PCM) that can release and absorb heat energy at nearly constant temperature by changing its state. Sodium nitrate (NaNO 3 ) and potassium nitrate (KNO 3 ) was selected to use as PCM in this project. This paper focus on the heat loading process and the melting process of the PCM in the energy storage using a computer simulation. The model of the energy storage was created as solid three dimensional modelling using computer aided software and the geometry size of it depend on how much it can apply to boil 1 kg of water in cooking application. The materials used in the tank, heat exchanger and the heat transfer fluid are stainless steel, copper and XCELTHERM MK1, respectively. The analysis was performed using a commercial simulation software in a transient state. The simulation run on different value of velocity but kept controlled under laminar state only, then the relationship of velocity and heat distribution was studied and the melting process of the PCM also has been analyzed. On the effect of heat transfer fluid velocity, the higher the velocity resulted in higher the rate of heat transfer. The comparison between the melting percentages of the PCMs under test conditions show that NaNO 3 melts quite faster than KNO 3 .

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Heat transfer characteristics in latent heat storage system using paraffin wax

Cited by 71 publications

References 19 publications

Compact PCM-based thermal stores for shifting peak cooling loads

Compact PCM-based thermal stores for shifting peak cooling loads

Melting and solidification performance in two horizontal shell‐and‐tube heat exchangers with different structures

Transient modelling of heat loading of phase change material for energy storage

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