Effects of evaporative cooling and CoolBot air conditioning on changes in the environmental conditions inside the cooling chamber
The main purpose of this study was to compare the effectiveness of low-cost evaporative cooler (EC), CoolBot-Air-Conditioner (CBAC) and combinations of EC and CBAC in terms of changes in temperature and relative humidity. The transient temperature and relative humidity (RH) distribution and the cooling efficiency of the cooling pads were evaluated. A Comparison of the changes in temperature and RH was also performed. The result indicates that the CBAC cooler can maintain the required temperature of the air inside the empty store room by reducing the temperature to 6°C compared to the ambient air temperature of 34.1°C. The CBAC cooling system achieved a total of 28.1°C temperature reduction. The RH decreased to about 75%, which is not within the optimum RH range for fruit and vegetables storage requirement. On the other hand, the temperature and RH achieved by EC+CBAC, when operated together (8-15°C and 80-99%) was within the optimum recommended range for fresh produces. The temperature achieved by EC (17-22°C) was not within the optimum range for many fruit and vegetables, while the RH (95-98.6%) achieved was in the optimum range required for the storage of fresh produces. In conclusion, the EC maintained only the RH but didn't reach the required temperature for short term storage, while EC+CBAC maintained both optimum temperature and RH required for fresh produces. Although, these technologies demonstrated a promising alternative for fresh produces shelf-life extension, further investigation in terms of a detailed fluid dynamics study of the micro-environment inside the cooler with load, taking in to account that the heat of generation from respiring plant materials is required for the optimization of the cooling technologies.
Tolesa, G.N. and Workneh, T.S. (2018). Effects of evaporative cooling and CoolBot air conditioning on changes in the environmental conditions inside the cooling chamber. Acta Hortic. 1201, 281-288
airspeed distribution, CoolBot-Air-Conditioner, evaporative cooler, temperature distribution, relative humidity distribution