Heat Storage Material Research Articles

Thermal control performance of phase change material combined with ultra-light hollow metallic microlattice for microsatellites

Phase change materials (PCMs) have been utilized to realize the passive thermal control of the large spacecrafts. To date, there have been few reports on the use of PCMs for the development of thermal control systems in microsatellites with small size and lightweight. Herein, we report a method of the fabrication of the microlattice phase change material (MPCM), which is a lightweight heat storage material using a combination of PCMs and hollow metallic microlattice materials. The thermal control performance of the MPCM is studied using a combination of theoretical analysis, experimental tests and numerical simulations. Parametric analysis reveals that the thermal control performance of MPCM is quite sensitive to the micro-structure of the microlattice. The equivalent heat flux is determined to realize the homogenization of the thermal properties of MPCM. Results obtained from the numerical simulation results reveal that as the macroscopic dimensions of MPCM are 10.3 cm × 10.3 cm × 1.9 cm with the weight of 59.4 g, the microsatellite can be operated over a period of 10000 s at temperatures ≤ 35 °C under conditions of heat load cycles and the temperature range can be controlled within 10.3 ℃. The properties of the developed MPCM can be tuned, and the material can be efficiently used to realize the thermal control of microsatellites.

A medium-temperature, tubeless heat exchanger based on alloy microencapsulated phase change material (MEPCM)/ceramic composites

High-performance heat storage materials and devices are urgently needed to meet the demand for efficient heat storage. Herein, a novel SnBi58 alloy microencapsulated phase change material (MEPCM)/ceramic composite with flow channels inside is fabricated for medium-temperature heat storage, which combines the characteristics of sensible heat storage (SHS) and latent heat storage (LHS). Then a tubeless heat exchanger based on the composite is constructed, and its heat storage performance is experimentally studied. The results show that the thermal conductivity of the composite-based heat exchanger is doubled (up to 3.09 W/(m·K)) and the heat storage density is increased by 30.4% to 559.1 MJ/m3 compared with the ceramic-based heat exchanger. Meanwhile, the heat storage performance of the heat exchanger can be improved with the increase of inlet temperature and mass flow rate, and it is more sensitive to the response of the inlet temperature. Furthermore, the average heat storage duty of the heat exchanger reaches 1183 W/(m3·°C), which is 3.56 times the mean value of other heat storage devices. Finally, test results confirm the high thermal reliability of the composite, which can meet the tubeless heat exchange requirements.

Isobaric storage of compressed air: Introduction of a novel concept based on phase change materials and pressure equalizing modules

In industrial compressed air systems (CAS), compressed air receivers have a significant impact on the overall energy efficiency. Isobaric compressed air receivers have the potential to increase the amount of stored air significantly and, hence, the energy efficiency can be improved compared to the usage of conventional isochoric compressed air receivers. In this work, we propose a novel concept of an isobaric compressed air receiver based on pressure equalizing modules (PEQM). These PEQM are filled with a condensable gas – in this work called phase change material (PCMl/g) – and are placed inside the receiver. During the charging and discharging of a compressed air receiver equipped with PEQM, the PCMl/g condenses or evaporates, respectively. Due to the large volume change during the phase change of the PCMl/g air can be stored isobarically. However, a proper selection of suitable PCMl/g is crucial for efficient and safe use. Therefore, we introduce a three-step selection process based on an adapted digital-logic method. In this selection process, qualitative (e.g. flammability) and quantitative (e.g., heat of condensation) properties are considered. As a result, R-1234ze(E) is selected as PCMl/g which owns a vapor pressure of 800 kPa at a temperature of 314.7 K. First experiments with the novel PEQM filled with R-1234ze(E) have been conducted in a lab-scale test plant and the results are shown in this work. The storage capacity of the test plant has been increased by 37.9 %. Additionally, the phase change of the PCMl/g during charging and discharging has been observed. However, the phase change is not isobaric yet. Temperature changes during the phase change inside the PEQM hinder the isobaric storing of the working gas. Therefore, proper heat management inside the PEQM is necessary, for example, by using a second phase change material for heat storage.

Dynamic absorption of bulk phase-change materials for photothermal solar energy storage based on reversible thermochromic

<p indent="0mm">Phase change materials (PCMs) are expected to solve the problems in thermal energy storage and thermal management. However, the energy density and power density of the transient melting front decrease as it moves away from the heat source. In the process of direct solar thermal utilization, the completion of the traditional heating totally depends on the thermal diffusion process of the PCM, and the low thermal conductivity limits the heating rate of the PCM. In this study, a dynamic phase-change material (Dyn PCM) based on reversible thermochromic properties is proposed that can automatically control the displacement of the light-thermal interface to follow the melting frontier. The thermal conductivity of the material would not limit the heating rate of the phase transition material during photothermal conversion. Dyn PCM is composed of two parts: a thermochromic agent and the main PCM. The thermochromic agent uses 2-phenylamino-3-methyl-6-dibutylaminofluoran as the electron donor, 2,2-bis(4-hydroxyphenyl)propane as the electron acceptor, and 4-benzyloxy Phenyl Ethyl Decanoate as a solvent to successfully achieve the transformation from transparent to black. The main PCM takes paraffin as an example. The latent heat of Dyn PCM_5, which contains 83.3 wt.% paraffin, is <sc>154.38 kJ/kg,</sc> which is only 6.6% lower than that of paraffin, and its transparent state shows transmittance of 91.2%, which is close to paraffin. The comparison shows that the charging rate of the Dyn PCM₅ is 260% faster than that of paraffin. The Dyn PCM groups remained unchanged after 80 cycles. The Dyn PCM did not change. Dyn PCM still has good reversible discoloration ability, maintains excellent thermal charge and discharge performance, and has stable light transmittance. As a result, the thermochromic composite Dyn PCM₅ developed in this study is a potential solar heat storage material that may also be used for direct solar energy absorption.

Diacid esters of 1-dodecanol as new alternatives to solid-liquid phase change materials for solar heat storage systems

ABSTRACT Ester-based phase change materials for heat storage have been an origin of interest for the last 2 decades due to their ease of production, different temperature options offered by the product, and the solutions they offered for the handicaps in the potential fatty acid and fatty alcohol thermal energy storage materials. In this study, synthesis, and characterization of 1-dodecanol esters of adipic acid, succinic acid, and oxalic acid were carried out. The novel esters were proven by proton nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FT-IR) spectroscopy techniques. In addition, the thermophysical properties of the synthesized esters were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) methods. The produced diacid esters of 1-dodecanol showed interestingly original behaviors that they melted (and crystallized) at 32.3 (30.3) oC , 30.5 (26.7) ℃, and 36.4 (33.0) ℃ which are higher than melting (and crystallization) temperatures of 1-dodecanol at 20.6 (20.6) ℃. Therefore, these compounds may have some specific applications like solar thermal storage.

Thermo-physical properties and thermal energy storage performance of two vegetable oils

Sensible heat storage materials are cheaper than latent heat storage materials for small storage volumes. Vegetable oils are cheap and readily available sensible heat storage materials produced locally in most countries in Sub-Saharan Africa. In this paper, the refractive indices, sound velocities, densities, specific heat capacities, and thermal conductivities of Sunflower oil and Roki oil (a blend of Palm oil and Sunflower oil) are determined experimentally. These two vegetable oils are locally produced in Uganda. Isentropic compressibility and thermal expansion coefficient are derived from the physical properties for the first time. The results show the refractive index, sound velocity, density, and thermal conductivity decrease with the increase in temperature, whereas isentropic compressibility, thermal expansion coefficient, and specific heat capacity increase with the increase in temperature for both oils. Roki oil shows higher thermal conductivity values than Sunflower oil at various temperatures. Additionally, an experimental setup to compare the performance of Roki oil and Sunflower oil as sensible heat storage materials for domestic medium temperature applications is presented. Roki oil and Sunflower oil are experimentally compared using charging and discharging experiments. The charging/heating cycles are first simulated with electrical energy followed by experimental tests with solar energy using parabolic dish solar cookers. The thermal comparison is made in terms of the temperature profiles during charging, discharging and heat utilization processes. During charging, the results show that Roki oil attains higher maximum temperatures (170–233 °C) compared to Sunflower oil (160–210 °C). Roki oil shows higher temperatures (71–78 °C) during cooling compared to Sunflower oil (67–76 °C). Roki oil shows higher heat utilization temperatures compared to Sunflower oil. The results provide insights on the utilization of locally available materials in Uganda as sensible heat thermal energy storage which are cheaper than commercial solar heat transfer oils.

Exploration of steel slag for thermal energy storage and enhancement by Na2CO3 modification

Development of thermal storage material from recycled solid waste resources can further enhance the economic and environmental benefits of thermal energy storage system. Thermal properties of steel slag as sensible heat storage material are examined and further enhanced by Na2CO3 activation. The steel slag remains stable until 1200 °C in TG-DSC test, and the morphology kept unchanged after 200 thermal cycles (400–900 °C), indicating good thermal cyclic stability. The thermal energy storage density of steel slag is 797.9 kJ·kg−1 (400–900 °C), the thermal conductivity was measured as 0.505, 0.532 and 0.670 W·(m·K)−1 at 25, 250 and 500 °C, respectively. When the steel slag is further modified by Na2CO3, the morphology and phase of the material remained stable, and the DSC curve trend unchanged after thermal cycle. The thermal energy storage density reaches 997.0 kJ·kg−1 (400–900 °C), which is 25.3% higher than original steel slag. Even more, the thermal conductivity is 1.331, 1.323, 0.889 W·(m·K)−1 at 25, 250, and 500 °C, respectively, which is 32.7% higher than that of steel slag. Hence, the thermal properties of steel slag have been significantly improved by the developed Na2CO3 activation process.

An experimental comparative analysis of the appropriateness of different sensible heat storage materials for solar cooking

Solar energy is a significant energy source of outstanding sustainability, mainly used for heating and power production. There are numerous energy storage materials through which the performance enhancement of different solar heating systems is possible. In the present work, three different sensible heat storage materials, such as blackened pebbles, small pieces of masonry bricks, and small aluminium balls, have been experimentally studied for their thermal storage capacity inside a hot box cooker. All these materials have been used over the cooking plate of the tested cookers. Only three configurations have been developed to perform the stagnation and sensible heat tests. Notably, the authors have focused on a low-cost solution to enhance the thermal efficiency of a box cooker using sensible heat storage materials, especially for people from remote or rural areas. Even, a less educated consumer can easily apply the suggested technique to a box cooker through the Do-It-Yourself method. Results of the cooking trials have been found in favour of consumers and show the appropriateness of low-cost energy storage materials. These results also indicate a possibility of adopting all the tested models, mainly the cooker with aluminium balls, which is the best-configured cooker. This cooker has a thermal efficiency of about 59.61 %, cooking power of about 75.21 W, and thermal storage capacity of around 09 h/day. The estimated cost is approximately $47.06 for the best-configured cooker and its payback period is about 3.11 years.

Low-cost crushed-rock heat storage with oil or salt heat transfer

The demand for variable electricity and heat is met by fossil-fuel power plants because the power plant capital costs and the cost of storing fossil fuels are low. A low-carbon economy requires replacement of the storage function of fossil fuels to provide variable heat and electricity as needed. The Crushed Rock Ultra-large Stored Heat (CRUSH) system is a new technology with the goal to provide heat storage at an incremental capital cost of $2–4/kWh at scales of 10 s to 100 s of GWhs that enables economic daily to multi-week storage. CRUSH can be coupled to nuclear power plants, concentrated solar power (CSP) plants and thermal energy batteries to provide variable electricity and heat on demand. Sensible heat is stored in crushed rock—the lowest-cost heat-storage material. Heat is transferred to and from the crushed rock using nitrate salt or heat-transfer oils but these fluids do not store heat. Heat from a nuclear reactor, CSP plant or conversion of low-price electricity into heat is used to heat the salt or oil. The hot fluid is poured over the crushed rock, trickles downward by gravity through the rock, heats the rock and is collected by the drain pans under the crushed rock. To recover heat cold salt or oil is poured over hot crushed rock, trickles down by gravity while being heated and is collected by the drain pans under the crushed rock. The system design and engineering trade-offs are described. The technology is in the early stages of development.

Improving the freshwater production from tubular solar still using sensible heat storage materials

Higher productivity is considered an important parameter of solar still performance; tubular solar still (TSS) is being explored as a popular technique for improved productivity in recent days. Along with the improved shape of the solar still, the use of sensible heat storage materials in the solar still proved to be a beneficial way to increase productivity. The current study focuses on the experimental investigations on a TSS using jute cloth, iron pieces, and wire mesh as potential energy storage materials for improving its productivity. All experiments were carried out at a constant basin depth of 2 cm at Nagpur [21.1458° N, 79.0882° E] India. The TSS with wire mesh outperforms all other cases. When compared to a conventional tubular solar still, the use of wire mesh in TSS improves thermal and exergy efficiency by 35.1 % and 88.1 %, respectively. The experimental studies concluded that wire mesh has the highest productivity of all; an improvement of 41.35 %, 10.33 %, and 29.78 % was observed when compared to conventional solar stills, iron pieces, and jute cloth, respectively. The water cost per liter of fresh water obtained from TSS–Jute cloth, TSS-Iron pieces, and TSS-Wire mesh was about 0.00575, 0.00515, and 0.00499 US $/m2.

The establishment of Boron nitride@sodium alginate foam/polyethyleneglycol composite phase change materials with high thermal conductivity, shape stability, and reusability

Adopting organic phase change materials (PCMs) for the management of electronic devices is restricted by low thermal conductivity. In this paper, the composite PCMs are established by freeze-drying and vacuum impregnation. Herein, polyethylene glycol (PEG) is induced as heat storage materials, Boron nitride (BN) is embedded as filler stacking in an orderly fashion on the foam walls to improve thermal conductivity and sodium alginate (SA) is formed as supporting material to keep the shape of the composite stable. X-ray diffractometry, scanning electron microscopy-energy dispersive spectrometer, thermal gravimetric analysis, thermal conductivity meter, differential scanning calorimeter, and Fourier transform infrared were used to characterize the samples and thermal cycles were employed to measure the shape stability. The results exhibit the BN@SA/PEG composite PCMs have good chemical compatibility, stable morphology, and thermal stability. Due to the high porosity of foam, PEG endows the composite PCMs with high latent heat (149.11 and 141.59 J∙g –1 ). Simultaneously, BN@SA/PEG shows an excellent heat performance with high thermal conductivity (0.99 W∙m –1 ∙K –1 ), reusability, and shape stability, contributing the composite PCMs to application in the energy storage field. This study provides a strategy to manufacture flexible, long-serving, and shape-stable PCMs via introducing BN@SA foam as a storage framework, and these PCMs have great potential in thermal management in the electronic field.

A review on phase change materials: Development, Types, and Applications

Heat-storage materials that can be used to transition from one phase to another are known as phase change materials (PCM). This review article aims to highlight the history, iterations, and future value-adding of PCM in the sciences and engineering industries. This study discusses the many types of phase transition materials, as well as their encapsulations and applications. The study also includes findings from many experiments conducted around the world in order to offer a complete picture of overall advancement in the field of PCM.

Strength-Weakness-Opportunities-Threats-Unusual (SWOT-U) behavior analysis of silicon as phase change material for high-temperature latent heat storage

Strength-Weakness-Opportunities-Threats-Unusual (SWOT-U) behavior analysis of silicon as phase change material for high-temperature latent heat storage

Experimental Research on a Solar Energy Phase Change Heat Storage Heating System Applied in the Rural Area

Thermal energy storage technology can effectively promote the clean heating policy in northern China. Therefore, phase-change heat storage heating technology has been widely studied, both theoretically and experimentally, but there is still a lack of engineering application research. According to the characteristics of heating load in northern rural areas, a kind of solar heating system using phase-change materials (PCMs) for heat storage is proposed. Furthermore, a farmhouse is used to demonstrate the practical engineering applications of the heating system. The heating system consists of the phase-change heat storage device (PCHSD), solar thermal panels, and a floor radiant heating terminal, which can realize the effective utilization of solar energy. Considering solar power generation capacity, heating load characteristics of farm buildings, and the local electricity price model, four potential operation modes of the heating system are established. Then, the corresponding control strategies are proposed for the four operating modes. The actual operation data of the heating system under different operating modes were collected continuously, and the application effect of the heating system was evaluated from the aspects of thermal efficiency of the device, the renewable energy efficiency, thermal comfort level, and economy. The experimental results show that: (1) The thermal efficiency of the device is mainly affected by the heating load, which can reach more than 80% during the test period; (2) the renewable energy efficiency of the system is positively correlated with the solar radiation intensity, and the maximum can reach 100% when the solar radiation is sufficient; (3) the system maintains excellent thermal comfort in all conditions, with the average and the highest thermal comfort time accounting for 80% and 100%, respectively; (4) compared with the average level of existing clean heating technology, the annual operating cost of the system is reduced by 27.3%, and the economy is significant. The results show that the system achieves effective performance during the test period.

Thermal and chemical reliability of paraffin wax and its impact on thermal performance and economic analysis of solar water heater

In the current investigation, two hot water storage tank integrated evacuated tube collector systems have been designed and fabricated. In one of the systems, an evacuated tube integrated with PCM (phase change material) is termed a testing system while another evacuated tube system was left without PCM termed a reference system. Based on the experimental results, it has been found that the incorporation of paraffin wax in the testing system improved the thermal energy output. Also, the thermal cycling of selected PCM has undergone up to 1500 cycles and results showed very negligible changes in its chemical and thermal properties. The useful energy output of the system with PCM has been improved by 36.81 %, 26.97 %, and 22.72 % for Run_40oC, Run_45oC, and Run_50oC respectively. In addition to this, extra hot water obtained from the testing system was 14 L for Run_40oC, 5 L for Run_45oC, and 6 L for Run_50oC respectively as compared to the reference system. Concerning techno-economic analysis, on average, the value of per litre cost of production of hot water (CPL) by the proposed system and electric water heater was observed to be INR 0.16 and INR 0.48 respectively. The net present value of the proposed system was found to be approximately INR 11598 and total expenditure on the proposed system can be recovered after 4.07 years which is much shorter compared to the life of the proposed system.The present work removes the overheating issue of heat pipes and improves the performance of the system by modifying in design and utilization of paraffin wax as heat storage material.

Selecting rock types for very-low-cost crushed rock heat storage systems with nitrate salt heat transfer

Today the demand for variable electricity is met by fossil-fuel power plants because the capital costs and the cost of storing fossil fuels are very low. A low-carbon grid requires replacements for stored fossil fuels to provide variable heat and electricity as needed. The thermal energy replacement option is to send heat from nuclear and concentrated solar power (CSP) plants operating at full capacity to heat storage with variable heat output to the power block to provide variable electricity to the grid. Very low-priced electricity from wind and solar can also be converted into stored heat. Today the lowest-cost commercial heat storage systems are in CSP plants and use nitrate salt stored in hot and cold storage tanks. Advanced heat storage systems use nitrate salt for heat transfer but replace some or all the nitrate salt with lower cost crushed rock for heat storage. These systems may lower the capital cost of heat storage by a factor of five or more to several dollars per kWh of stored heat. Locally acquired crushed rock is the lowest-cost heat-storage material but not all rock is compatible with heat storage requirements including chemical compatibility, mechanical properties, and durability under thermal cycling. Rocks have been sorted into categories likely, possibly, and unsuitable and the basis for these conclusions has been documented. Potentially suitable rock types include basalt, peridotite, taconite, quartzite, quartzitic sandstone and serpentinite. Except for taconite, sedimentary rocks are unlikely to be suitable for service.

Comparative Analysis of Hybrid Photovoltaic Thermal (PV/T) Solar Dryer

As the world’s population is increasing, the demand for food is also increasing. Drying techniques increase the life and quality of crop and industrial food products. It also improves the economic condition of farmers. Drying reduces the water stored within the product by evaporation. It can be done by the use of conventional energy and different methods. Sun radiation is used for open sun drying around the globe. Open sun drying has many disadvantages in comparison to other drying techniques. Solar drying is comparatively clean and effective. Solar dryers are of mainly four types: 1) direct solar dryer; 2) indirect solar dryers; 3) mixed mode solar dryer and 4) hybrid solar dryers. Because electric and heat energy demand is increasing day by day worldwide, PV/T solar dryer becomes an interesting and upcoming interest of research nowadays. In this review article basics of different kinds of solar dryers and recent advancements in hybrid PV/T dryers have been presented. Results for drying grapes, medicinal herb, tomato, and wood using PV/T solar dryer are discussed in this study. Variations of drying time, energy consumption, efficiency with different air temperatures, air flow rate and RH are discussed. The use of different solar collectors, solar air heater and heat storage materials with hybrid PV/T dryer have also been reviewed.

Investigation of the Heat Storage Capacity and Storage Dynamics of a Novel Polymeric Macro-Encapsulated Core-Shell Particle Using a Paraffinic Core

Thermal energy storages represent important devices for the decarbonisation of heat; hence, enabling a circular economy. Hereby, important tasks are the optimisation of thermal losses and providing a tuneable storage capacity, as well as tuneable storage dynamics for thermal energy storage modules which are composed of either sensible or phase change-based heat storage materials. The thermal storage capacity and the storage dynamics behaviour are crucial for fulfilling certain application requirements. In this work, a novel macro-encapsulated and spherical heat storage core-shell structure is presented and embedded in a supercritical ammonia working fluid flow field. The core of the macro-capsule is built by an organic low molecular weight substance showing a solid–liquid phase transition in a respective temperature zone, where the shell structure is made of polyvinylidene fluoride. Due to the direct coupling of computational fluid dynamics and the simulation of the phase transition of the core material, the influence of the working fluid flow field and shell thickness on the time evolution of temperature, heat transfer coefficients, and accumulated heat storage is investigated for this newly designed material system. It is shown that due to the mixed sensible and phase change storage character, the shell architecture and the working fluid flow field, the heat storage capacity and the storage dynamics can be systematically tuned.

A novel composite phase change material of high-density polyethylene/d-mannitol/expanded graphite for medium-temperature thermal energy storage: Characterization and thermal properties

As pure phase change materials (PCM) filling in supporting porous material are often unfavorable for thermal energy storage (TES) due to the easy leakage, low thermal conductivity, and reduced overall latent heat, composite phase change materials (CPCMs) receive the increasing attention for the future applications. In this work, a novel medium-temperature CPCM was prepared by the method of melt adsorption-compression molding, which used d-mannitol (DM) as PCM, high-density polyethylene (HDPE) as supporting material, and expanded graphite (EG) as thermal enhancement material. The thermophysical properties of such CPCMs were measured and analyzed to identify the optimal material design. The results showed that the leaking of DM from the HDPE/DM composite can be avoided under the 30 % mass loading of HDPE, showing a better adsorption capacity. Among the prepared examples, the CPCM3 (26.4 % HDPE + 61.6 % DM + 12 % EG) has the highest thermal conductivity of 2.66 W/(m·K) which is 6.04 times higher than the pure HDPE/DM composite. The CPCM3 also has other favorable characteristics such as a constant melting temperature of around 163.2 °C, high latent heat of 224.1 J/g, supercooling degree of 37.4 °C, and decomposition temperature of 411.3 °C. The complex influencing mechanisms were further explored with the help of material microstructure characterization. This study is significant because it provides design guidelines for reliable medium-temperature heat storage materials for advanced renewable energy applications.

Heat Transfer Characteristics of Modular Heat Storage Wall Solar Greenhouse Based on Active Heat Storage System

The modular heat storage wall is a new type of solar greenhouse wall structure, which has the advantages of fast construction and good heat storage ability. This study provides data reference and practical value for producing modular heat storage wall in the construction of a solar greenhouse. In this paper, we used different heat storage materials to construct the modular wall. In the winter thermal environment test, soil module solar greenhouse (SG) and stone module solar greenhouse (PG) were controlled against each other in two greenhouses. The test results for 28 consecutive days (31 January 2021 9:00 to 28 February 2021 9:00) showed that both greenhouses could effectively increase the temperature in greenhouse by 10–12 °C. The average temperature of SG was 0.86 °C lower than that of PG during the daytime (09:00–17:00) and 0.44 °C higher than that of PG during the nighttime (17:00–09:00). Under typical sunny conditions, the average temperature differences between the inlet and outlet of SG in the heat storage and exothermic stage was less than that of PG, and the relative humidity difference was greater than that of PG. This indicated that SG had a better performance of heat preservation than PG and could raise the nighttime temperature rapidly. Under the condition of a typical cloudy day, the average temperature difference between the inlet and outlet was SG &lt; PG and the relative humidity difference was SG &gt; PG in the exothermic stage, which was consistent with the conclusion of sunny days. In the storage and exothermic stages of typical sunny days and cloudy days, the total heat exchange of SG was 464.87, 110.44 and 54.82 MJ and the total heat exchange of PG was 264.16, 61.60 and 46.89 MJ, respectively. Moreover, the heat storage and release of SG were more than that of PG in all stages. In summary, the thermal performance of the modular heat storage wall heliogreenhouse could meet the growth of tomato crop, in which the heat transfer performance of SG was optimum.