Experimental study on cold storage box with nanocomposite phase change material and vacuum insulation panel

Abstract

Summary To maintain the quality of fruits, vegetables, and other agricultural products during cold chain transportation, a constant temperature in the range of −5°C to 8°C is optimal. In this work, a thermal storage material, containing sodium polyacrylate, multiwalled carbon nanotubes (MWCNTs), and water, was prepared in a polyethylene cold storage plate, which was then placed in a vacuum insulation box. The prepared material exhibits high economic efficiency, a phase transition temperature of −0.037°C, and latent heat of 335.4 J/g sodium polyacrylate (PASS) system. The thermal conductivity of 1% sodium polyacrylate and water was 0.757 W/(m·K), which increased by 19.17% to 0.9021 W/(m·K) after the addition of 0.1% MWCNT. The cryogenic transport box was constructed with composite nanomaterial and vacuum insulation plate, and yoghurt was used as the test sample. The experimental results show that the nanocomposite phase change material can effectively maintain cold temperatures in the box for 87 hours, and the viscosity and pH of yoghurt remained in an acceptable range for this time period. The vacuum insulation board also effectively ensures the quality of food, good cold insulation performance, and therefore high feasibility.

Solar Cookers and Dryers: Environmental Sustainability and Nutraceutical Content in Food Processing

“…When comparing sensible and latent heat storages, it is evident that latent heat storage produces smaller temperature changes than sensible heat but higher energy storage capacity and lower energy losses during phase change. Moreover, the exploitation of this storage mode generally allows good control [44,[65][66][67]. For all these reasons, latent heat storage is the most exploited thermal storage technique in solar cookers.…”

Improving the performance of air conditioning systems by using phase change materials: A review

“…Latent heat is generated by using PCMs that can store or release thermal energy during the phase transition with an increased or decreased ambient temperature. Some benefits of latent heat storage include its neglectable temperature variations, the high energy storage density between the melting and solidification stages, and its easy process control . Compared with conventional sensible heat storage, PCMs store 5 to 14 times more thermal energy per unit volume due to their exceptional energy density.…”

“…Recent studies have also begun to examine air conditioning systems that incorporate thermal storage; these systems produce the cooling capacity that they need for air conditioning at nighttime when the demand for air conditioning is low and then utilize such capacity at daytime to satisfy the peak load . PCMs are often employed in air conditioning systems to shift the peak load to the off‐peak time, thereby reducing the system scale, minimizing the partial load operation to improve the overall efficiency, improving the system coefficient of performance (COP) via extended nighttime operations at low environment temperatures, reducing the financial cost by producing and storing cold energy at nighttime when electricity generation is cheap, and releasing cold energy at daytime when electricity generation is expensive …”

Gas film heat transfer as enhancement strategy for phase change materials

“…Those techniques of heat transfer enhancement based in adapted geometric configurations and extended surfaces; and those techniques in which heat transfer enhancement is attained by directly modifying in some way the thermal conductivity of the PCM. In the first category we have, for example, the use of fins, heat pipes, or fillers, and in the second category we have the use of encapsulation; or microencapsulation of the PCM as well as the use of nanoparticles including nanotubes or nanocomposites . There are copious available literature of the topic and specially in the last advancements in PCMs, and for the interested reader on various techniques of heat transfer enhancement in latent heat thermal energy storage systems it is recommended the up‐to‐date review on the state‐of‐the‐art as well as critical review …”

“…In the first category we have, for example, the use of fins, heat pipes, or fillers, 1 and in the second category we have the use of encapsulation 2,3 ; or microencapsulation 4,5 of the PCM as well as the use of nanoparticles including nanotubes 6 or nanocomposites. 7 There are copious available literature of the topic and specially in the last advancements in PCMs, and for the interested reader on various techniques of heat transfer enhancement in latent heat thermal energy storage systems it is recommended the up-to-date review on the state-of-the-art as well as critical review. 8 In this work, consideration is given to an alternative strategy for phase change materials (PCMs) heat transfer enhancement with particular reference to horizontal plates in which the enhancement is attained neither by adapted geometries nor modification of the thermal heat transfer coefficients of the PCM but rather by preventing the formation, and contact of the front of solidification and the wall by the deliberate presence of a gas film covering the surface which limits the growth of the solidified layer to a certain critical thickness before gravitationally sinks by its own weight.…”