全闭式谷物干燥机热泵系统的优化与研究试验

Optimization and research on a fully closed heat pump system for grain dryer

摘要

[目的]为进一步降低干燥能耗，解决开式和半开式热泵性能受环境工况影响较大、对环境污染大的问题，本研究开发了一种带旁通的全闭式热泵干燥系统并确定最佳旁通比。[方法]通过三维建模及仿真试验，研究环境温度和旁通比对热泵性能及干燥过程的影响，获得不同环境温度条件下最佳旁通比。分别利用自研带旁通全闭式热泵干燥机与半封闭热泵干燥机，在干燥温度为45℃与环境温度为10~25℃的条件下，开展不同旁通比的稻谷干燥试验，测定稻谷含水率、风量、温湿度和系统能耗等，计算稻谷干燥速率、除湿能耗比(SMER)和热泵性能系数(COP)，验证并确定全闭式热泵系统的最佳旁通比和适宜的环境温度条件。[结果]仿真试验结果表明:随着进风温度升高，蒸发器热回收量逐渐减少;随着风速的增加，蒸发器的热回收率逐步增大，在风速为7m·s^-1时，热回收率接近峰值，进一步增加风速后，热回收率增加幅度很小;在相同的回风状态下，随着旁通比的增加，热回收量逐步下降。在回风温度为27~30℃、旁通比为0.3~0.5时，热回收量最大。生产试验表明，在环境温度为10~25℃条件下，当旁通比为0.5时，热泵的COP最大，为4.36。相较于半封闭热泵，带旁通全闭式热泵的COP和SMER分别提高15.1%和36.1%，干燥品质更高。[结论]利用带旁通的全闭式热泵干燥机进行稻谷干燥，不仅能进一步降低干燥能耗，而且干燥品质更高，更适合江淮地区稻谷的干燥。

Abstract

[Objectives] In order to further reduce the drying energy consumption, and solve the problem that the performance of open and semi-open heat pumps is greatly affected by the environmental conditions and pollutes the environment, a fully closed heat pump drying system with bypass was developed and the optimal bypass ratio was determined. [Methods] Through three-dimensional modeling and simulation test, the influence of ambient temperature and bypass ratio on the performance of heat pump and drying process was studied, and the optimal bypass ratio was obtained under different ambient temperature conditions. Using the self-developed fully-closed heat pump dryer with bypass and the semi-closed heat pump dryer respectively, the paddy drying test with different bypass ratios was carried out under the conditions of drying temperature of 45°C and ambient temperature of 10-25°C to determine the paddy moisture content, air volume, temperature and humidity, and system energy consumption, etc., and the drying rate of paddy, the dehumidification energy consumption ratio (SMER) and the coefficient of performance (COP) of the heat pump were calculated, and the optimal performance of the fully-closed heat pump system was verified and determined. The optimal bypass ratio and suitable ambient temperature conditions of the fully closed heat pump system were verified and determined. [Results] Simulation test results show that, with the increase of the inlet air temperature, the evaporator heat recovery gradually decreased; with the increase of wind speed, the heat recovery rate of the evaporator gradually increased, the heat recovery rate was close to the peak when the wind speed was 7 m·s^-1, and the heat recovery rate increased very little after further increasing the wind speed; the heat recovery gradually decreased with the increase of the bypass ratio under the same return air condition. At a return air temperature of 27-30°C, and a bypass ratio of 0.3-0.5, the maximum heat recovery was achieved. The production test showed that the COP of the heat pump was 4.36 when the bypass ratio was 0.5 under the condition of ambient temperature of 10-25°C. Compared with the semi-closed heat pump, the COP and dehumidification energy consumption ratio of the fully-closed heat pump with bypass were improved by 15.1% and 36.1% respectively, and the drying quality was higher. [Conclusions] Utilizing a closed heat pump dryer with bypass for paddy drying not only further reduced drying energy consumption, but also had higher drying quality and was more suitable for drying paddy in the JA region.

关键词

空气源热泵 / 旁通技术 / 仿真分析 / 稻谷 / 干燥 / 热泵性能系数(COP)

Key words

air-source heat pump / bypass technology / simulation analysis / paddy / drying / coefficient of performance (COP)

参考文献

[1] Panigrahi S S, Luthra K, Singh C B, et al. On-farm grain drying systems sustainability: current energy and carbon footprint assessment with potential reform measures[J]. Sustainable Energy Technologies and Assessments, 2023, 60: 103430.

[2] 盛韶阳， 吴敏， 胡纯秋， 等. 热风-真空复合工艺干燥玉米力学特性研究[J]. 农业机械学报， 2020， 51(增刊1): 476-482.

[3] Sheng S Y, Wu M, Hu C Q, et al. Mechanical properties of maize kernel dried by hot-air-vacuum compound process[J]. Transactions of the Chinese Society for Agricultural Machinery, 2020, 51(Supp1): 476-482(in Chinese with English abstract).

[4] 李广伟， 孙玉田， 孙健超， 等. 空气源热泵机组在粮食烘干领域的应用[J]. 粮食与食品工业， 2020， 27(3): 55-57， 60.

[5] Li G W, Sun Y T, Sun J C, et al. Application of air source heat pump unit in the field of grain drying[J]. Cereal & Food Industry, 2020, 27(3): 55-57, 60(in Chinese).

[6] 姚克恒， 彭卓敏， 朱继平， 等. 我国粮食晾晒收集现状与机械化发展对策分析[J]. 江苏农业科学， 2014， 42(11): 417-420.

[7] Yao K H, Peng Z M, Zhu J P, et al. Analysis on the present situation of grain drying and collection in China and the development countermeasures of mechanization[J]. Jiangsu Agricultural Sciences, 2014, 42(11): 417-420(in Chinese).

[8] 郎少华， 冯荣， 曹岗林， 等. 回热式热泵干燥系统温湿度智能调控策略研究[J]. 智能化农业装备学报(中英文)， 2026， 7(1): 96-104.

[9] Lang S H, Feng R, Cao G L, et al. Research on air volume ratio control strategy of heat pump drying system with regenerator[J]. Journal of Intelligent Agricultural Mechanization, 2026, 7(1): 96-104(in Chinese with English abstract).

[10] Ma Y X, Gao E Y, Zhang X S, et al. Parametric analysis and design optimization of a fully open absorption heat pump for heat and water recovery of flue gas[J]. Applied Energy, 2024, 375: 124144.

[11] 吴宗达. 太阳能喷射增压式空气源热泵系统性能研究[D]. 太原:太原理工大学， 2023.

[12] Wu Z D. Performance research of solar ejector-enhanced air-source heat pump system[D]. Taiyuan: Taiyuan University of Technology, 2023(in Chinese with English abstract).

[13] Shahzad M K, Ding Y Q, Zhang H, et al. Energy efficiency analysis of novel combined open absorption multifunctional heat pump and Flash ME desalination system with a compressed air dryer[J]. Desalination, 2024, 582: 117662.

[14] 颜建春， 谢焕雄， 魏海， 等. 5H-1.5A型花生换向通风干燥机研制[J]. 农业工程学报， 2019， 35(10): 9-18.

[15] Yan J C, Xie H X, Wei H, et al. Development of 5H-1.5A peanut reversing ventilation dryer[J]. Transactions of the Chinese Society of Agricultural Engineering, 2019, 35(10): 9-18(in Chinese with English abstract).

[16] 刘紫薇， 贲宗友， 杨浩勇， 等. 粮食烘干机变频式热泵系统的开发及试验研究[J]. 南京农业大学学报， 2022， 45(6): 1286-1294.

[17] Liu Z W, Ben Z Y, Yang H Y, et al. Design of heat pump system of variable frequency grain dryer and rice drying experiment[J]. Journal of Nanjing Agricultural University, 2022, 45(6): 1286-1294(in Chinese with English abstract).

[18] 郭焱华， 邵双全， 李浩， 等. 基于数据驱动研究空气源热泵除霜效果研究[J]. 工程热物理学报， 2024， 45(3): 628-634.

[19] Guo Y H, Shao S Q, Li H, et al. A data-driven evaluating method on the defrosting effect of the air source heat pump system[J]. Journal of Engineering Thermophysics, 2024, 45(3): 628-634(in Chinese with English abstract).

[20] 成家豪， 曹祥， 葛美才， 等. 用于海苔烘干的湿冷双效回收型高效热泵系统[J]. 制冷学报， 2021， 42(5): 140-145.

[21] Cheng J H, Cao X, Ge M C, et al. Seaweed heat pump dryer with latent heat and cooling energy recovery[J]. Journal of Refrigeration, 2021, 42(5): 140-145(in Chinese with English abstract).

[22] Liu S C, Li X Q, Song M J, et al. Experimental investigation on drying performance of an existed enclosed fixed frequency air source heat pump drying system[J]. Applied Thermal Engineering, 2018, 130: 735-744.

[23] 梁士民， 王伟， 孙育英， 等. 抑霜型空气源热泵机组应用实测研究[J]. 制冷学报， 2022， 43(5): 24-32.

[24] Liang S M, Wang W, Sun Y Y, et al. Field study on the application of frost-suppression air-source heat pump units[J]. Journal of Refrigeration, 2022, 43(5): 24-32(in Chinese with English abstract).

[25] Jin W, Wang Y X. Three-dimensional model construction of a frost-free air source heat pump evaporator and its performance analysis[J]. Results in Engineering, 2024, 22: 102001.

[26] 吴文婧. 空气源热泵技术在稻谷烘干中的应用与研究[D]. 扬州:扬州大学， 2020.

[27] Wu W J. Application and research of air source heat pump technology in grain drying[D]. Yangzhou: Yangzhou University, 2020(in Chinese with English abstract).

[28] Zhao H B, Wu K. Annual performance analysis of heat pump drying system with waste heat recovery[J]. Sustainable Energy Technologies and Assessments, 2022, 53: 102625.

[29] Jokiel M, Bantle M, Kopp C, et al. Modelica-based modelling of heat pump-assisted apple drying for varied drying temperatures and bypass ratios[J]. Thermal Science and Engineering Progress, 2020, 19: 100575.

[30] Meng Z F, Zhang F, Liu Y, et al. Experimental study on thermal performance of a closed heat pump drying system[J]. Case Studies in Thermal Engineering, 2023, 51: 103590.

[31] Hou Y X, Wu W D, Li Z B, et al. Effect of drying air supply temperature and internal heat exchanger on performance of a novel closed-loop transcritical CO₂ air source heat pump drying system [J]. Renewable Energy, 2023, 219: 119516.

[32] 杜江凌. 基于TRNSYS的茯砖茶烘房空气源热泵系统运行特性研究[D]. 西安:西安建筑科技大学， 2022.

[33] Du J L. Research on operation characteristics of fu brick tea drying room air source heat pump system based on TRNSYS modeling[D]. Xi'an: Xi'an University of Architecture and Technology, 2022(in Chinese with English abstract).

[34] 朱烨， 江涛， 张现广， 等. 海带自然晾晒与热泵烘干级联干燥自动控制系统研制[J]. 农业工程学报， 2020， 36(19): 298-305.

[35] Zhu Y, Jiang T, Zhang X G, et al. Development of automatic control system for natural drying and heat pump drying of kelp cascade drying[J]. Transactions of the Chinese Society of Agricultural Engineering, 2020, 36(19): 298-305(in Chinese with English abstract).

[36] 过增元， 赵甜， 薛提微. 逆卡诺循环与逆p-V循环性能分析[J]. 中国科学:技术科学， 2018， 48(11): 1190-1198.

[37] Guo Z Y, Zhao T, Xue T W. The performance analysis of reversed Carnot cycle and reversed p-V cycle[J]. Scientia Sinica Technologica, 2018, 48(11): 1190-1198(in Chinese with English abstract).

[38] 陈东. 热泵技术手册[M]. 北京:化学工业出版社， 2012.

[39] Chen D. Technical Manual of Heat Pump[M]. Beijing: Chemical Industry Press, 2012(in Chinese).

[40] 夏军勇， 黎宇辉. 基于Realizable k-ε湍流模型的山楂片热风干燥数值模拟[J]. 包装与食品机械， 2023， 41(6): 82-87.

[41] Xia J Y, Li Y H. Numerical simulation of hawthorn slice drying by hot air based on Realizable k-ε turbulence model[J]. Packaging and Food Machinery, 2023, 41(6): 82-87(in Chinese).

基金资助

2023年江苏省现代农机装备与技术示范推广项目(NJ2023-09)