Heat Thermal Energy Storage Material Research Articles

Analysis of efficient building for energy conversion and storage using phase change material

Building energy efficiency is now a top priority because of the major negative effects that may happen on the society, the economy, and the environment. In various parts of the world, several researchers have worked on ways of achieving methods that can use phasechange materials as thermal storage. This is because these technologies have the potential to greatly reduce energy consumption when combined with solar power. PCMs store thermal energy in ways quite different than ordinary construction materials. These materials make use of latent heat rather than sensible heat. Therefore, phase-changed materials possess a notable advantage over sensible heat thermal energy storage materials with respect to storing and releasing heat. As a result, this paper was concerned with exploring the possibility of building energy conversion and storage systems using phase change material.

A comprehensive review of the thermal performance in energy efficient building envelope incorporated with phase change materials

As the world's largest energy consumer, the building sector is under growing pressure to reduce energy consumption and CO2 emissions. To confront this challenge, the thermal performance of building elements, especially for cooling purposes, must be enhanced. One promising solution involves the incorporation of PCMs to augment a building's thermal mass. Unlike traditional building materials that store thermal energy sensibly, PCMs store it in a latent form by undergoing phase transitions at constant temperatures. This unique characteristic allows PCMs to store and release more heat efficiently than sensible heat thermal energy storage materials. As a result, PCMs have emerged as a prominent solution for passive cooling and heating applications in buildings. This paper proposes a systematic review of existing literature, classifying it based on building components and effective PCM integration methods while considering climatic influences. The primary objective is to comprehensively analyze the application of PCMs within building envelopes to enhance indoor thermal comfort. This study explores various methods for assessing the thermal properties of PCMs and PCM composites. Notably, integrating PCMs into building components like walls and roofs has shown remarkable potential in reducing energy consumption within the building envelope. This approach is precious in lightweight construction, where conventional passive design strategies may fall short. This study aims to bridge the existing research gap and provide valuable insights for designing energy-efficient buildings across diverse climates by systematically evaluating the impact of directly incorporating thermal energy storage systems into building components.

Experimental investigation of inclined solar still with and without sand as energy storage materials

A Novel Inclined Solar still (ISS) assessed by sand as Sensible Heat Thermal Energy Storage Material (SHTESM) was fabricated with the view of improving yield. The performance of the ISS with and without SHTESM has been experimented in Chennai, India. The use of sand materials placed on the basin keeps the basin temperature high enough to yield higher distilled water during the evening time. The effect of sand as SHTESM on energy and exergy efficiencies was calculated. The calculation revealed that the energy and exergy efficiencies were maximum when ISS was assessed by sand materials. The diurnal yield was found to be 2.3 and 1.7 kg for the ISS with and without sand, respectively. The results showed that the yield of the ISS with sand was 35 % higher than the ISS without sand. The maximum energy and exergy efficiencies of the ISS without SHTESM are 30.4 % and 1.6 %, and for the ISS with SHTESM are 40.1 % and 2.2 %, respectively.

Analysis of energy storage materials for developments in solar cookers.

Solar energy is accessible freely and can be utilized for many household and industrial applications. The consumption of solar energy for cooking applications has found significant success. Various innovations have been employed in facilitating cooking during off-sunshine hours. Thermal energy storage helps in overcoming the fluctuations in the supply of energy required for cooking during different time periods of the day. This study focuses on the different types of thermal energy storage mediums that are currently utilized in solar cooking. Primarily, oils and pebbles are most commonly used as sensible heat storage (SHS) while organic phase change materials (PCMs) are used as latent heat thermal energy storage materials (LHTES). The properties and performances of various SHS and latent heat storage (LHS) mediums have been compared for their suitable utilization. SHS materials are cost-effective but have lower thermal gradient compared to LHTES materials. The energy storage capability of LHTES is high while degradation with the increasing number of charging and discharging cycles is also considerable. The melting point should be close to the utilization temperature for being used as LHTES as thermal diffusivity of the materials greatly influences the performance of solar cookers. The cooking time is lower for solar cooking systems equipped with energy storage compared to non-equipped cooking systems. It is recognized that the use of energy storage has been proved as a huge advantage to solar cooking systems, however, the design, and heat transfer characteristics of the cooking vessel along with the storage material type and volume must be optimized in order to make this technology more influential.

Analysis of energy storage materials for developments in solar cookers

Solar energy is accessible freely and can be utilized for many household and industrial applications. The consumption of solar energy for cooking applications has found significant success. Various innovations have been employed in facilitating cooking during off-sunshine hours. Thermal energy storage helps in overcoming the fluctuations in the supply of energy required for cooking during different time periods of the day. This study focuses on the different types of thermal energy storage mediums that are currently utilized in solar cooking. Primarily, oils and pebbles are most commonly used as sensible heat storage (SHS) while organic phase change materials (PCMs) are used as latent heat thermal energy storage materials (LHTES). The properties and performances of various SHS and latent heat storage (LHS) mediums have been compared for their suitable utilization. SHS materials are cost-effective but have lower thermal gradient compared to LHTES materials. The energy storage capability of LHTES is high while degradation with the increasing number of charging and discharging cycles is also considerable. The melting point should be close to the utilization temperature for being used as LHTES as thermal diffusivity of the materials greatly influences the performance of solar cookers. The cooking time is lower for solar cooking systems equipped with energy storage compared to non-equipped cooking systems. It is recognized that the use of energy storage has been proved as a huge advantage to solar cooking systems, however, the design, and heat transfer characteristics of the cooking vessel along with the storage material type and volume must be optimized in order to make this technology more influential.

Emerging applications of phase change materials: A concise review of recent advances

AbstractPhase change materials (PCMs) are used as latent heat thermal energy storage materials. The fields of application for PCMs are broad and diverse. Among these areas are thermal control of electronic components and thermal building regulations. These areas are used as heat and cold storage materials. The low thermal conductivity of PCMs is one of the significant and severe technological problems of PCMs. This paper presents a review of the latest works using PCMs in the thermal management of electronic components, buildings, and heat exchangers. Besides, it provides concise pieces of information on the classification of PCMs, their advantages, disadvantages, and thermal storage systems.

A cycling study for reliability, chemical stability and thermal durability of polyethylene glycols of molecular weight 2000 and 10000 as organic latent heat thermal energy storage materials

In this experimental study, thermal aging test for investigating the variations in thermal and chemical properties of two selected organic phase change materials (PCMs) has been carried out. Polyethylene glycols (PEGs) of molecular weight of 2000 and 10 000 have been considered as potential latent heat thermal energy storage (LHTES) materials for investigation. The aim of this study is to identify the probable variations in thermal properties and chemical structures of PEGs after melting/freezing cycles repeated for 1500 times. The differential scanning calorimetry (DSC) technique was adopted for measuring the thermal properties such as melting point and latent heat of PCMs. In order to study the variations in PCM's chemical functional groups, Fourier transform infrared (FT-IR) spectroscopy was used. Thermal durability property after the cycling test was investigated using thermogravimetric analysis. The DSC measurements indicated that PEG2000 experienced a maximum variation of about 4°C in melting point while the latent heat of fusion reduces by 16% after the cycle test. PEG10000 shows a variation of about 0.3°C in melting point and 15% of the latent heat of melting after the entire cycle test. The spectral investigation confirms that there are no variations in the functional groups of selected materials after cycle test, which can be inferred as chemical stability of them. The thermal gravimetric analysis curves show that both PEGs are thermally quite durable as well after such large number of melt/freeze cycles. Thermal cycling results and economic analysis confirm that both PEGs are potential PCMs for passive solar thermal management purposes. Highlights Synthesis of polyethylene glycol-based binary eutectic mixtures. Accelerated thermal cycle test of eutectic mixtures. Binary mixtures were found chemically stable. Charging/discharging rates of PEG are controlled. Novelty Statement This paper presents the thermal performance of two polyethylene glycols, viz., PEG2000 and PEG10000. These materials were melted and solidified 1500 times for testing their suitability as thermal energy storage materials, and it was found that these materials are stable enough to store solar energy for five years. They found to be suitable for many solar energy storage applications.

Thermoanalytical investigation of sodium acetate trihydrate for application as a latent heat thermal energy storage material

The thermal behaviour of sodium acetate trihydrate (NaAc · 3H2O) was investigated by DTA, Q-TG and measurements of the solubility properties. The nucleation efficiency of Na4P2O7 · 10H2O for the crystallization of NaAc · 3H2O melts is not stable over long periods. Stratification can be ascribed to the formation of anhydrous sodium acetate in the supercooled melts. Under static heat storage conditions, NaAc · 3H2O and Na4P2O7 · 10H2O do not exhibit stable behaviour.

Investigation of latent heat thermal energy storage materials: V. thermoanalytical evaluation of binary eutectic mixtures and compounds of NAOH with NaNO 3 OR NaNO 2

Differential scanning calorimetry was applied to the evaluation of binary eutectic mixtures and compounds of NaOH with NaNO 3 or NaNO 2 as latent heat thermal energy storage materials. There are two compounds and three eutectic mixtures consisting of NaOH and NaNO 3 and one compound and two eutectic mixtures consisting of NaOH and NaNO 2. The heats of fusion of all compounds and mixtures were more than 200 J g −1. The thermal behaviour of these materials was observed, and some compounds and mixtures show a great tendency to supercool. The specific heat capacity was also measured. Because the eutectic mixture 18.5 mol.% NaNO 3-81.5 mol.% NaOH is the most promising material for use in a nuclear power plant, this mixture made from industrial products was examined further. After 1000 cycles of melting and crystallization in bench-scale equipment the material shows little change.

A Stefan-Type Problem with Void Formation and its Explicit Solution

For most materials, the densities of the solid and liquid phases are different. For some materials being considered as potential latent heat thermal energy storage materials, this density change is large. When the solid phase is more dense than the liquid, solidification may result in the formation of vapour bubbles or voids. We have formulated a problem, representing a phase change process with such a void, that has an explicit solution. We examine the solution to gain a further understanding of the thermal and phase change performance of a material in which such voids form. We use the solution to analyse an example problem involving freezing lithium fluoride, a candidate phase-change material with a density change on freezing of about 25 per cent.

Thermal energy storage for solar heating and off-peak air conditioning

Latent heat thermal energy storage materials suitable for solar heating and off-peak air conditioning were investigated and evaluated in terms of criteria developed to judge their usefulness. The often recommended sodium sulfate decahydrate and its mixtures were shown to have undesirable melting properties, causing a reduction in storage capacity upon repeated cycling. Materials more suitable at present are paraffin waxes for solar heating and paraffin waxes and tetrahydrofuran hydrate for off-peak air conditioning. Sensible heat storage has the economic advantage of not requiring heat transfer surfaces between storage and collection and between storage and delivery. Latent heat storage provides operational advantages of smaller temperature swings and lower, more efficient solar collector temperature, smaller size and lower weight per unit of storage capacity. The optimization of the thermal energy storage subsystem is dependent on the collection and delivery characteristics of the system. Parametric designs for two latent heat materials (sodium thiosulfate pentahydrate and a paraffin wax) and for a sensible heat material (a 1:1 mixture of water and ethylene glycol) were compared as to cost, performance, and space requirements. The conditions of equal cost for latent heat and sensible heat storage systems were determined as functions of latent heat capacity, thermal conductivity, and the temperature swing allowed in the sensible heat storage tank. The comparative designs include the cost of the heat exchanger required for latent heat storage and the operating penalty due to storage temperature swings inherent in sensible heat storage.