# Use of Phase Change Materials for Food Applications--State of the Art in 2022
## 3 Summary and Conclusions  
\"Food\", essentially meaning what we eat and drink, is the basis of human life besides the air we breathe. Insufficient availability, including too high prices, is a main cause of poverty, even political instability. Nowadays, energy consumption for supply of food is significant in many stages, so rising energy prices consequently lead to rising food prices. Even more, large parts of food produced are lost by spoilage. Spoilage is related to further problems: production of more food than finally consumed causes avoidable energy consumption, greenhouse gas emissions, pollution with fertilizers, pesticides, and also land-use. The reduction of food loss, as well as of food related energy consumption, is thus of great importance. In this work, an overview on the state-of-the-art of the wide use of PCM for food applications was given. The applications were grouped as belonging to food processing, storage and transport, or production. Food processing means transformation of natural products into food, or of one form of food into another. This comprises modifying food to make natural products edible or turning ingredients into familiar food, for example by various cooking methods. It also comprises modifying food for food preservation, crucial to use food later, also at different places, thus after food storage and transport. Therefore, processing also includes the thermal treatment by boiling, drying, as well as cooling food down to avoid spoilage. With respect to energy, the amount of energy required for food transformation is often a crucial issue. State-of-the-art are multi-purpose cold storages, mainly ice storage, for various cooling applications. Multi-purpose heat storages just have become commercially available in recent years. Specific use is, for small farms, in small milk pre-coolers, pre-coolers for freshly harvested food, and also solar drying. Still in the R&D stage is the use of storages for distilleries and beer brewing, and the use in solar cookers. Beverage cooling, by adding ice cubes or by using ice storages to tap cold beer, is also state-of-the-art. Food storage and transport is, regarding thermal energy, dominated by the need for food preservation. Therefore, keeping food at the right temperature, and minimizing heat exchange, is in the foreground. Most common is storage of food cold, called refrigerated, typically at 4-8 \({}^{\circ}\)C for shorter periods, and freezing it, typically at \(-18\)\({}^{\circ}\)C, for longer periods. Since water/ice and eutectic mixtures of water and salts are cheap PCM, their use is widespread. And other PCM are entering the commercial use. Commercial storage applications are cooling of supermarkets, larger as well as smaller storage rooms, small coolers and freezers, buffet cooling, and of course the use of ice directly on marketplaces etc. Directly using ice is also used to transport fish. For transport however widespread use is today also in bags, boxes, and small containers. The use of PCM for cold storage to cool the compartments on vans, trucks, or trailers, to avoid inefficient use of gasoline to run a cooler, has successfully entered the market. Use for cooled containers, for flexible transport by truck and train, just started commercial application. Food production has not yet received the same attention as food processing, storage, and transport. Heating of greenhouses and thermal water desalination have until recently in large-scale facilities been done using fossil fuels. Only for small-scale applications the application of PCM for better use of solar thermal energy has been investigated intensively. However, with rising energy prices, interest increases. Finally, one field of application not mentioned earlier should be mentioned now. It just came up recently, and fits not to any of the application groups discussed before. According a recent article [106], PCM can also be used for management of food waste, and at the same time to supply renewable energy.