Food Engineering Progress
Korean Society for Food Engineering
Article

열펌프를 이용한 벼의 저온건조성능평가

김훈1, 한재웅2,*
Hoon Kim1, Jae-Woong Han2,*
1한국식품연구원
2성균관대학교 생명공학부
1Food Marketing Research Group, Korea Food Research Institute
2Faculty of Life Science and Technology, Sungkyunkwan University
*Corresponding author: Jae-Woong Han, Faculty of Life Science and Technology, Sungkyunkwan University, Suwon Gyeonggi 440-740, Korea, Tel: +82-31-290-7832; Fax: +82-31-290-7830, E-mail: hanwoong@empal.com

ⓒ Copyright 2009 Korean Society for Food Engineering. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Oct 12, 2009; Revised: Nov 12, 2009; Accepted: Nov 14, 2009

Published Online: Nov 30, 2009

Abatract

This study was conducted to design and fabricate a heat pump that can produce some weather conditions similar to those of the dry season of the rough rice in Korea, and to investigate basic performances of the apparatus. During the drying test, the amount of energy consumption and drying characteristics were measured at four different temperature levels ranging between 20°C and 50°C. In the psychrometric chart, the freezing capacity and refrigerant circulation ratio of the heat pump were 173 kJ/kg and 49.6 kg/hr, respectively. Therefore, coefficient of performance was 5.5, which was superior to that of refrigerant R-22 (4.0) in standard refrigeration cycle. In addition, the time to reach target drying temperature (30°C) and relative humidity (40%) were 6 minutes and 7 minutes, respectively. Temperature differences between the drying temperature and the rice were 1.5°C and 8.5°C at the drying temperatures of 21.9°C and 48.7°C, respectively. This result demonstrated that the increased temperature of the rice in the drying section decreased sufficiently in the tempering section. At the drying temperatures of 21.9, 30.7 38.8, and 48.7°C, drying rates were 0.29, 0.61, 0.85, and 1.26%/hr, respectively, which were similar to those of commercial dryer. In addition, the amounts of energy consumption were 325, 667, 692, and 776 kJ/kg, respectively. These results showed that this dryer saved up to 86% of energy consumption compared with the commercial dryer, which uses 4,000-5,000 kJ/kg of fossil fuel.

Keywords: Heat pump; low temperature drying; energy consumption; rough rice