Background
Food Spoilage: Background
In our society food spoils at a mass rate. According to researchers from medical news today the average U.S. household wastes 31.9% of the food that its members obtain (Sharkey 2020.) It's a huge issue in the U.S, and in a developing country where food is scarce, it's crucial to keep food for extended periods during months of low harvest. One type of food spoilage is microbiological. “Many types of bacteria, such as pseudomonads, lactic, micrococci, and coliforms, grow readily on agricultural and horticultural plants. (Sperber 2009.)” The processing of foods removes most of the harmful bacteria before packaging, but leftover bacteria begin to eat away at the foods. This begins the processing of biodegrading food which is an exponential process that as soon as the first signs of food being broken down begins to be seen the faster it begins to break down but there might be a solution. “As the temperature is decreased, the growth rate of bacteria slows and the growth stops at temperatures below the minimum growth temperature (Sperber 2009.)” So temperature is a direct influence on the growth of bacteria which is a direct influence on food spoilage. In order to better preserve the food, the temperature of the food in question should be kept low. To receive this low temperature we have created a large carbon footprint, but cheaper & more environmentally friendly options also exist.
Cold & Humidity & High-tech:
For years the way to achieve lower temperatures to keep food cold was to use ice, but in regions without the ability to harvest or create ice they were out of luck. Eventually, fridges were developed which use a compressor to circulate refrigerant throughout the system, “As the refrigerant turns from a liquid into a gas through evaporation, it cools the area around it, producing the proper environment for storing food. (How Does a Refrigerator Work? 2022.)” This process takes energy and lots of it. Eventually, fridges became the standard for keeping food cold to prevent spoilage. “Data was combined in a database and translated into fridge requirements. Five temperature zones for non-frozen food were identified to fit the storage recommendations for fruit, vegetables, meat, fish, dairy, and bread (Holsteijn, Freija van, and René Kemna. 2022.)” In many cases, one temperature setting on a fridge is recommended for one type of food but not another. In developed regions households one fridge is the standard for storing a variety of foods, packaged in many different kinds of packages. “If growth is initiated, the heat generated will further encourage microbial activity and could eventually result in substantial localized temperature rise. (R. F. Milton, R.K. Pawsey, 2022.)” Humidity is a factor of heat in a moist environment. More heat means more humidity which means more bacteria which will cause food to spoil quicker in the wrong conditions. To combat humidity companies have come up with the solution of sealed packages to reduce the heat and humidity able to reach the food.
The Solutions?
In the realm of food storage, low-tech options also exist for developing regions, such as ZECC, a Zero Energy Cooling Chamber that has been tested to increase the shelf‐life of vegetables by keeping them in a cool environment. Figure 5: ZECC
Figure 5: “The structure consisted of a rectangular, double-walled chamber carrying heat-insulating detachable roof. Each of the 4 composite sides consisted of 2 inter-spaced walls and this jacketed type room has the advantage of preventing heat leakage into the storage cabin. (Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. 2010.) Water is used to cool the space which is why it's crucial to be near a source of water, as it requires water to be added 3 to 4 times a day for optimum cooling. In testing, they found “The average temperature values reduced from an ambient condition of 34 to 27 ℃ in summer and 21 to 17℃ in winter (Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. 2010.)” They also found the optimum water content needs to vary during the winter and summer months to create an optimum result. “The annular space gets saturated at certain levels of water application depending on different climatic conditions. (Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. 2010.)” They were also able to study the need to change the amount of water depending on the region's climate, this would include having to change results for humid climates like tropical regions. This chamber found a low-tech solution to finding the optimum temperature & humidity for peak freshness of stored vegetables.
Evaporative Cooling Effect:
Evaporative cooling is the effect that will allow the sun to cool the ZECC Chamber. In order to develop the best ZECC environment we must understand how it works. The reason the body sweats is based on evaporative cooling effect. How it works. Yang Explains it best "Evaporative cooling is based on the fact that water must absorb heat in order to change from liquid state to vapor state, converting sensible heat to enthalpy of vapour, resulting in the reduction of system temperature. (Yang, Cui, Lan. 2019.)" To capture this effect we must isolate the main components water and heat. These isolated components can work in tandem to cool and environment.
In our society food spoils at a mass rate. According to researchers from medical news today the average U.S. household wastes 31.9% of the food that its members obtain (Sharkey 2020.) It's a huge issue in the U.S, and in a developing country where food is scarce, it's crucial to keep food for extended periods during months of low harvest. One type of food spoilage is microbiological. “Many types of bacteria, such as pseudomonads, lactic, micrococci, and coliforms, grow readily on agricultural and horticultural plants. (Sperber 2009.)” The processing of foods removes most of the harmful bacteria before packaging, but leftover bacteria begin to eat away at the foods. This begins the processing of biodegrading food which is an exponential process that as soon as the first signs of food being broken down begins to be seen the faster it begins to break down but there might be a solution. “As the temperature is decreased, the growth rate of bacteria slows and the growth stops at temperatures below the minimum growth temperature (Sperber 2009.)” So temperature is a direct influence on the growth of bacteria which is a direct influence on food spoilage. In order to better preserve the food, the temperature of the food in question should be kept low. To receive this low temperature we have created a large carbon footprint, but cheaper & more environmentally friendly options also exist.
Cold & Humidity & High-tech:
For years the way to achieve lower temperatures to keep food cold was to use ice, but in regions without the ability to harvest or create ice they were out of luck. Eventually, fridges were developed which use a compressor to circulate refrigerant throughout the system, “As the refrigerant turns from a liquid into a gas through evaporation, it cools the area around it, producing the proper environment for storing food. (How Does a Refrigerator Work? 2022.)” This process takes energy and lots of it. Eventually, fridges became the standard for keeping food cold to prevent spoilage. “Data was combined in a database and translated into fridge requirements. Five temperature zones for non-frozen food were identified to fit the storage recommendations for fruit, vegetables, meat, fish, dairy, and bread (Holsteijn, Freija van, and René Kemna. 2022.)” In many cases, one temperature setting on a fridge is recommended for one type of food but not another. In developed regions households one fridge is the standard for storing a variety of foods, packaged in many different kinds of packages. “If growth is initiated, the heat generated will further encourage microbial activity and could eventually result in substantial localized temperature rise. (R. F. Milton, R.K. Pawsey, 2022.)” Humidity is a factor of heat in a moist environment. More heat means more humidity which means more bacteria which will cause food to spoil quicker in the wrong conditions. To combat humidity companies have come up with the solution of sealed packages to reduce the heat and humidity able to reach the food.
The Solutions?
In the realm of food storage, low-tech options also exist for developing regions, such as ZECC, a Zero Energy Cooling Chamber that has been tested to increase the shelf‐life of vegetables by keeping them in a cool environment. Figure 5: ZECC
Figure 5: “The structure consisted of a rectangular, double-walled chamber carrying heat-insulating detachable roof. Each of the 4 composite sides consisted of 2 inter-spaced walls and this jacketed type room has the advantage of preventing heat leakage into the storage cabin. (Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. 2010.) Water is used to cool the space which is why it's crucial to be near a source of water, as it requires water to be added 3 to 4 times a day for optimum cooling. In testing, they found “The average temperature values reduced from an ambient condition of 34 to 27 ℃ in summer and 21 to 17℃ in winter (Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. 2010.)” They also found the optimum water content needs to vary during the winter and summer months to create an optimum result. “The annular space gets saturated at certain levels of water application depending on different climatic conditions. (Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. 2010.)” They were also able to study the need to change the amount of water depending on the region's climate, this would include having to change results for humid climates like tropical regions. This chamber found a low-tech solution to finding the optimum temperature & humidity for peak freshness of stored vegetables.
Evaporative Cooling Effect:
Evaporative cooling is the effect that will allow the sun to cool the ZECC Chamber. In order to develop the best ZECC environment we must understand how it works. The reason the body sweats is based on evaporative cooling effect. How it works. Yang Explains it best "Evaporative cooling is based on the fact that water must absorb heat in order to change from liquid state to vapor state, converting sensible heat to enthalpy of vapour, resulting in the reduction of system temperature. (Yang, Cui, Lan. 2019.)" To capture this effect we must isolate the main components water and heat. These isolated components can work in tandem to cool and environment.
Sources
Bylykbashi, Kliton, and Giuseppe Bonifazi. “Energy Efficiency for a Farm Company: NZEFC – Nearly Zero Energy Farm Company. Case of Study,” n.d., 7.
“Culture of Laos.” In Wikipedia, January 8, 2022. https://en.wikipedia.org/w/index.php?title=Culture_of_Laos&oldid=1064388052.
Hammond, Sean T., James H. Brown, Joseph R. Burger, Tatiana P. Flanagan, Trevor S. Fristoe, Norman Mercado-Silva, Jeffrey C. Nekola, and Jordan G. Okie. “Food Spoilage, Storage, and Transport: Implications for a Sustainable Future.” BioScience 65, no. 8 (August 1, 2015): 758–68. https://doi.org/10.1093/biosci/biv081.
Hays, Jeffrey. “LAO ARCHITECTURE | Facts and Details.” Accessed February 3, 2022. https://factsanddetails.com/southeast-asia/Laos/sub5_3c/entry-2967.html.
Holsteijn, Freija van, and René Kemna. “Minimizing Food Waste by Improving Storage Conditions in Household Refrigeration.” Resources, Conservation and Recycling 128 (January 1, 2018): 25–31. https://doi.org/10.1016/j.resconrec.2017.09.012.
“How Does a Refrigerator Work? | How the Fridge Works | Danfoss.” Accessed February 7, 2022. https://www.danfoss.com/en/about-danfoss/our-businesses/cooling/the-fridge-how-it-works/.
Kumar, Ratnesh, Suresh Chandra, Balwant Singh, and A Anil Kumar. “Zero Energy Cool Chamber for Food Commodities: Need of Eco-Friendly Storage Facility for Farmers: A Review,” n.d., 9.
Lee, Haksung, Akihito Ozaki, Myonghyang Lee, and Wanghee Cho. “A Fundamental Study of Intelligent Building Envelope Systems Capable of Passive Dehumidification and Solar Heat Collection Utilizing Renewable Energy.” Energy and Buildings 195 (July 15, 2019): 139–48. https://doi.org/10.1016/j.enbuild.2019.04.039.
Mishra, Anand, Sanjeet Jha, Kriti Ghimire, and Ujjwol Subedi. “Study on Zero Energy Cool Chamber (ZECC) for Storage of Mango.” International Journal of Scientific and Research Publications (IJSRP) 10 (January 24, 2020): p9766. https://doi.org/10.29322/IJSRP.10.01.2020.p9766.
R . F .MiltonR.K. Pawsey. “PII: 0168-1605(88)90040-2 | Elsevier Enhanced Reader.” Accessed February 5, 2022. https://doi.org/10.1016/0168-1605(88)90040-2.
Rayaguru, Kalpana, Md K. Khan, and N. R. Sahoo. “Water Use Optimization in Zero Energy Cool Chambers for Short Term Storage of Fruits and Vegetables in Coastal Area.” Journal of Food Science and Technology 47, no. 4 (August 2010): 437–41. https://doi.org/10.1007/s13197-010-0072-7.
Sharkey, Lauren. “How Much Food Does the Average US Household Waste?,” February 9, 2020. https://www.medicalnewstoday.com/articles/study-suggests-u-s-households-waste-nearly-a-third-of-the-food-they-acquire.
Singh, Sanjay, A. K. Singh, H. K. Joshi, K. Lata, B. G. Bagle, and T. A. More. “Effect of Zero Energy Cool Chamber and Post-Harvest Treatments on Shelf-Life of Fruits under Semi-Arid Environment of Western India. Part 1. Ber Fruits.” Journal of Food Science and Technology 47, no. 4 (August 2010): 446–49. https://doi.org/10.1007/s13197-010-0074-5.
Sperber, William H., and Michael P. Doyle, eds. Compendium of the Microbiological Spoilage of Foods and Beverages. New York, NY: Springer New York, 2009. https://doi.org/10.1007/978-1-4419-0826-1.
Yang, Yifan, Gary Cui, and Christopher Q. Lan. “Developments in Evaporative Cooling and Enhanced Evaporative Cooling - A Review.” Renewable and Sustainable Energy Reviews 113 (October 1, 2019): 109230. https://doi.org/10.1016/j.rser.2019.06.037.
“ZECC Ppt.Pdf.” Accessed February 5, 2022. https://srrweb.cc.lehigh.edu/app/static/ZECC%20ppt.pdf.