Comparative analysis of energy efficiency and economy of CO2 transcritical heat pump system under heating condition

doi:10.16085/j.issn.1000-6613.2020-0905

Abstract

Abstract:

In order to improve the performance of the CO₂ transcritical heat pump heating system, a heat recovery system with secondary air supply for two-stage compression and double gas cooler is proposed. Through the establishment of the thermodynamic model, the impact of various factors on the energy efficiency of the system is analyzed combined with the other three CO₂ heat pump systems and the R134a single-stage compression regenerative system. In addition, the total investment situation of each system in different cities during the operating cycle is studied based on typical annual meteorological parameters by an economic evaluation model, which comprehensively considers the initial investment cost and annual operating cost. The results show that the heat recovery system with secondary air supply for two-stage compression and double gas cooler is the optimal system scheme, which has the highest COP_h and exceeds that of R134a single-stage compression regenerative system. When the ambient temperature is 0℃ and the temperature of outlet/return water is 65℃/40℃, the theoretical COP_h can reach 2.58, which is 9.1% higher than that of the R134a system, and 22.5% higher than that of CO₂ single-stage compression system, and the compressor discharge temperature doesn't exceed the existing temperature limit. In the selected sampling cities, the total investment cost of all heat pump systems during the operating cycle is the lowest in Shanghai and the highest in Shenyang, which shows that it is greatly affected by the climate region. Due to the high cost of the CO₂ compressor, the total investment cost of the CO₂ heat pump system is higher than that of the R134a system. With the improvement of CO₂ heat pump technology and the expansion of production scale, when the cost of the compressor is reduced by 80%, the total investment cost of the heat recovery system with secondary air supply for two-stage compression and double gas cooler will be lower than that of R134a system.

Key words: CO₂ heat pump, transcritical, heating, energy efficiency, economy

摘要：

为提高CO₂跨临界热泵采暖系统的性能，提出了双级压缩双气冷器中间补气回热系统。结合其他3种CO₂热泵系统和R134a单级压缩回热系统，通过建立热力学模型，分析各因素对系统能效的影响。此外，通过构建综合考虑初始投资成本和年运行成本的经济性评价模型，结合典型年气象参数，研究不同城市中各系统在运行周期内的总投资情况。结果表明，CO₂热泵系统中，双级压缩双气冷器中间补气回热系统最优COP_h最高且可以超过R134a单级压缩回热系统，在环境温度为0℃、出水/回水温度为65℃/40℃时，理论性能系数（COP_h）可达2.58，比R134a系统高9.1%，比CO₂单级压缩系统高22.5%，且排气温度不超过现有压缩机排气温度极限，是能效最优系统。在选定样本城市中，热泵系统运行周期内的总投资成本在上海最低，而在沈阳最高，可见总投资成本受气候区域影响较大。由于CO₂压缩机成本过高，CO₂热泵系统的总投资成本高于R134a系统。随着CO₂热泵技术的提高和生产规模的扩大，当压缩机成本降低80%，CO₂双级压缩双气冷器中间补气回热系统的总投资成本将低于R134a系统。

关键词: CO₂热泵, 跨临界, 采暖, 能效, 经济

CLC Number:

TK124

LIU Xuetao, LI Minxia, MA Yitai, YAO Liang, ZHAN Haomiao. Comparative analysis of energy efficiency and economy of CO₂ transcritical heat pump system under heating condition[J]. Chemical Industry and Engineering Progress, 2021, 40(3): 1315-1324.

刘雪涛, 李敏霞, 马一太, 姚良, 詹浩淼. CO₂跨临界热泵系统采暖工况下能效和经济对比分析[J]. 化工进展, 2021, 40(3): 1315-1324.

Figures/Tables 18

参数	城市
参数	沈阳	北京	上海
供暖面积/m²	100	100	100
HLET/℃	18	18	18
设计采暖室外温度/℃	-16.9	-7.6	-0.3
建筑采暖热指标/W·m^-2	69	61.8	58

设备	公式
CO₂压缩机	C_com(CO₂)=17547W^0.4488
R134a压缩机	C_com(R134a)=758.15W^0.8728
套管式换热器	C_HE,_tube-in-tube=1874.4W^0.9835
翅片管式换热器	C_HE,_fin-tube=331.7A^0.9390

换热器类型	参数	数值/mm
套管式换热器	外管外径	19
	外管管壁厚度	2
	内管外径	7
	内管管壁厚度	1
翅片管式换热器	管外径	7
	管壁厚度	0.7
	翅片厚度	0.15
	翅片间距	2
	横向管间距	21
	纵向管间距	18.166
	迎风长度	400
	迎风宽度	170

类别	关联式
CO₂蒸发侧^[17]	$N u = 0.00061 S + F × R e L × F a 0.01 × P r L 0.4 l n 1.024 μ L, b μ L, w$ ， $S = 41000 × B o 1.13 - 0.275$ ， $F = x 1 - x a ρ L ρ V 0.4$ ， $a = 0.48 + 0.00524 R e L × F a 0.11 0.85 - 5.9 × 10 - 6 R e L × F a 0.11 1.85 R e L × F a 0.11 < 600 0.87 600 ≤ R e L × F a 0.11 ≤ 6000 160.8 R e L × F a 0.11 0.6 R e L × F a 0.11 > 6000$
CO₂气冷侧^[18]	$N u = f f 8 R e b - 1000 × P r 1.07 + 12.7 f f 8 × P r 2 / 3 - 1$ ， $P r = c p, b μ b λ b c p, b ≥ c ˉ p c ˉ p μ b λ b c p, b < c ˉ p ? 和 ??? μ b λ b ≥ μ f λ f c ˉ p μ f λ f c p, b < c ˉ p ? 和 ??? μ b λ b ≥ μ f λ f$
R134a蒸发侧^[19]	$h = 0.55 h f m 1 + 3000 × B o 0.86 + 1.12 x 1 - x 0.7 ρ L ρ V 0.41 × F a 0.48$ $h f m = 0.023 G 1 - x D h μ L 0.9 × P r L 0.4 × λ L D h$ ， $F a = 1 x ≤ 0.7 1 + 0.2 x 1.2 c o s 15 ° x > 0.7$
R134a冷凝侧^[20]	$N u = 0.05 × R e e q 0.8 × P r L 0.33$ ， $R e e q = R e V × μ V μ L ρ L ρ V 0.5 + R e L$
空气侧^[21]	$h = h 4 ρ a ω m a x c p, a P r a 2 / 3$ ， $h 4 = 0.0014 + 0.2618 × R e d - 0.4 × A A t - 0.15$
单相工质流动^[22]	$N u = f 8 R e - 1000 × P r 1.07 + 12.7 f 8 × P r 2 / 3 - 1$

类别	关联式
CO₂蒸发侧^[17]	$N u = 0.00061 S + F × R e L × F a 0.01 × P r L 0.4 l n 1.024 μ L, b μ L, w$ ， $S = 41000 × B o 1.13 - 0.275$ ， $F = x 1 - x a ρ L ρ V 0.4$ ， $a = 0.48 + 0.00524 R e L × F a 0.11 0.85 - 5.9 × 10 - 6 R e L × F a 0.11 1.85 R e L × F a 0.11 < 600 0.87 600 ≤ R e L × F a 0.11 ≤ 6000 160.8 R e L × F a 0.11 0.6 R e L × F a 0.11 > 6000$
CO₂气冷侧^[18]	$N u = f f 8 R e b - 1000 × P r 1.07 + 12.7 f f 8 × P r 2 / 3 - 1$ ， $P r = c p, b μ b λ b c p, b ≥ c ˉ p c ˉ p μ b λ b c p, b < c ˉ p ? 和 ??? μ b λ b ≥ μ f λ f c ˉ p μ f λ f c p, b < c ˉ p ? 和 ??? μ b λ b ≥ μ f λ f$
R134a蒸发侧^[19]	$h = 0.55 h f m 1 + 3000 × B o 0.86 + 1.12 x 1 - x 0.7 ρ L ρ V 0.41 × F a 0.48$ $h f m = 0.023 G 1 - x D h μ L 0.9 × P r L 0.4 × λ L D h$ ， $F a = 1 x ≤ 0.7 1 + 0.2 x 1.2 c o s 15 ° x > 0.7$
R134a冷凝侧^[20]	$N u = 0.05 × R e e q 0.8 × P r L 0.33$ ， $R e e q = R e V × μ V μ L ρ L ρ V 0.5 + R e L$
空气侧^[21]	$h = h 4 ρ a ω m a x c p, a P r a 2 / 3$ ， $h 4 = 0.0014 + 0.2618 × R e d - 0.4 × A A t - 0.15$
单相工质流动^[22]	$N u = f 8 R e - 1000 × P r 1.07 + 12.7 f 8 × P r 2 / 3 - 1$

References 24

1	李嵩. F-Gas新法规: 不可小觑的影响力——访欧盟委员会官员Cornelius Rhein [J]. 制冷与空调, 2014, 14(5): 12-14.
	LI Song. New F-Gas regulations: the influence that can’t be underestimated——Interview with European Commission official Cornelius Rhein[J]. Refrigeration and Air-conditioning, 2014, 14(5): 12-14.
2	MANCINI F, MINETTO S, FORNASIERI E. Thermodynamic analysis and experimental investigation of a CO₂ household heat pump dryer[J]. International Journal of Refrigeration, 2011, 34(4): 851-858.
3	SAIKAWA M, KOYAMA S. Thermodynamic analysis of vapor compression heat pump cycle for tap water heating and development of CO₂ heat pump water heater for residential use[J]. Applied Thermal Engineering, 2016, 106: 1236-1243.
4	俞彬彬, 王丹东, 向伟, 等. 跨临界CO₂电动汽车空调系统性能分析[J]. 上海交通大学学报. 2019, 53(7): 866-872.
	YU Binbin, WANG Dandong, XIANG Wei, et al. Performance analysis of a trans-critical CO₂ air conditioning system for electric vehicle[J]. Journal of Shanghai Jiaotong University, 2019, 53(7): 866-872.
5	胡余生, 刘雪涛, 李敏霞, 等. CO₂跨临界热泵系统特性再分析[J]. 化工进展, 2020, 39(4): 1252-1258.
	HU Yusheng, LIU Xuetao, LI Minxia, et al. Reanalysis of characteristics of CO₂ transcritical heat pump system[J]. Chemical Industry and Engineering Progress, 2020, 39(4): 1252-1258.
6	陈子丹, 罗会龙, 刘锦春, 等. 寒冷地区CO₂空气源热泵供暖运行性能分析[J]. 化工学报, 2018, 69(9): 4030-4036.
	CHEN Zidan, LUO Huilong, LIU Jinchun, et al. Analysis of heating performance of CO₂ air-source heat pump in cold region[J]. CIESC Journal, 2018, 69(9): 4030-4036.
7	李椿, 王志华, 王沣浩, 等. CO₂热泵研究现状及展望[J]. 制冷学报, 2018, 39(5): 1-9.
	LI Chun, WANG Zhihua, WANG Fenghao, et al. Research status and prospects of the CO₂ heat pump[J]. Journal of Refrigeration, 2018, 39(5): 1-9.
8	王国梁, 姜培学. 具有补气特性的跨临界二氧化碳制冷系统理论研究[J]. 清华大学学报(自然科学版), 2008(2): 224-227.
	WANG Guoliang, JIANG Peixue. Theoretical investigation of trans-critical carbon dioxide refrigeration system with a compressor economizer[J]. Journal of Tsinghua University (Science and Technology), 2008(2): 224-227.
9	BAEK Changhyun, Jaehyeok HEO, JUNG Jongho, et al. Performance characteristics of a two-stage CO₂ heat pump water heater adopting a sub-cooler vapor injection cycle at various operating conditions[J]. Energy, 2014, 77: 570-578.
10	李敏霞, 王派, 刘雪涛, 等. 双级压缩中间补气CO2三级回热冷却热泵/制冷系统: CN201920311572.X[P]. 2020-01-21.
	LI Minxia, WANG Pai, LIU Xuetao, et al. A two-stage compression intermediate vapor supply CO2 regenerator cooling heat pump/refrigeration system: CN201920311572.X[P]. 2020-01-21.
11	李敏霞, 刘雪涛, 王派, 等. 一种喷气增焓CO2三回热冷却热泵/制冷系统: CN201920319082.4[P]. 2020-03-20.
	LI Minxia, LIU Xuetao, WANG Pai, et al. A enhanced vapor injection CO2 three-regenerator cooling heat pump/refrigeration system: CN201920319082.4[P]. 2020-03-20.
12	中国建筑科学研究院. 民用建筑供暖通风与空气调节设计规范: [S]. 北京: 中国建筑工业出版社, 2012.
	China Academy of Building Research. Design code for heating ventilation and air conditioning of civil buildings: [S]. Beijing: China Architecture & Building Press, 2012.
13	European Committee for Standardization. Energy performance of buildings-overall energy use and definition of energy ratings: EN 15603-2008[S]. 2008.
14	宋芳婷, 诸群飞, 吴如宏, 等. 中国建筑热环境分析专用气象数据集[C]//全国暖通空调制冷2006学术年会, 2006.
	SONG Fangting, ZHU Qunfei, WU Ruhong,et al. Meteorological data set for building thermal environment analysis of China[C]// National Academic Conference of HVAC and Refrigeration, 2006.
15	DAI Baomin, QI Haifeng, LIU Shengchun, et al. Environmental and economical analyses of transcritical CO₂ heat pump combined with direct dedicated mechanical subcooling (DMS) for space heating in China[J]. Energy Conversion and Management, 2019, 198: 111317.
16	FAZELPOUR F, MOROSUK T. Exergoeconomic analysis of carbon dioxide transcritical refrigeration machines[J]. International Journal of Refrigeration, 2014, 38: 128-139.
17	FANG Xiande. A new correlation of flow boiling heat transfer coefficients for carbon dioxide[J]. International Journal of Heat and Mass Transfer, 2013, 64: 802-807.
18	DANG Chaobin, HIHARA E. In-tube cooling heat transfer of supercritical carbon dioxide (): experimental measurement[J]. International Journal of Refrigeration. 2004, 27(7): 736-747.
19	MOHSENI S G, AKHAVAN-BEHABADI M A. Flow pattern visualization and heat transfer characteristics of R-134a during evaporation inside a smooth tube with different tube inclinations[J]. International Communications in Heat and Mass Transfer, 2014, 59: 39-45.
20	CAVALLINI A, ZECCHIN R. A dimensionless correlation for heat transfer in forced convection condensation[C]// International Heat Transfer Conference Digital Library. Begel House Inc., 1974.
21	MCQUISTON F C. Heat, mass and momentum transfer data for five plate-fin-tube heat transfer surfaces[J]. ASHRAE Transactions, 1978, 84(1): 266-293.
22	GNIELINSKI V. New equations for heat and mass transfer in turbulent pipe and channel flow[J]. International Chemical Engineering, 1976, 16(2): 359-368.
23	LIU Shengchun, LI Zheng, DAI Baomin, et al. Energetic, economic and environmental analysis of air source transcritical CO₂ heat pump system for residential heating in China[J]. Applied Thermal Engineering, 2019, 148: 1425-1439.
24	WANG Dandong, YU Bingbing, HU Jichao, et al. Heating performance characteristics of CO₂ heat pump system for electrical vehicle in a cold climate[J]. International Journal of Refrigeration, 2018, 85: 27-41.

[1]	HUI Bo, HOU Hongyi, ZHANG Tao, CHE Shengwen. Drying characteristics of cylindrical annular pulsating heat pipe [J]. Chemical Industry and Engineering Progress, 2023, 42(S1): 33-40.
[2]	SHAO Zhiguo, REN Wen, XU Shipei, NIE Fan, XU Yu, LIU Longjie, XIE Shuixiang, LI Xingchun, WANG Qingji, XIE Jiacai. Influence of final temperature on the distribution and characteristics of oil-based drilling cuttings pyrolysis products [J]. Chemical Industry and Engineering Progress, 2023, 42(9): 4929-4938.
[3]	LYU Jie, HUANG Chong, FENG Ziping, HU Yafei, SONG Wenji. Performance and control system of gas engine heat pump based on waste heat recovery [J]. Chemical Industry and Engineering Progress, 2023, 42(8): 4182-4192.
[4]	HOU Dianbao, HE Maoyong, CHEN Yugang, YANG Haiyun, LI Haimin. Application analysis of resource allocation optimization and circular economy in development and utilization of potassium resources [J]. Chemical Industry and Engineering Progress, 2023, 42(6): 3197-3208.
[5]	WANG Zijie, LU Shuyin, ZHAO Ziliang, WANG Ning, GU Yujiong. Analysis of the influence of heating transformation on the performance of thermal power unit [J]. Chemical Industry and Engineering Progress, 2023, 42(5): 2325-2331.
[6]	LU Nan, WANG Haimin, WANG Chuanwei, HU Xuebin, ZHOU Jiangang, LIU Wenqin, ZHAO Feng, MENG Guodong. Thermal characteristics and improved discharge parameters of NCM811 traction battery immersed preheated by insulating oil [J]. Chemical Industry and Engineering Progress, 2023, 42(3): 1299-1307.
[7]	LIU Hongru, LIN Wensheng. Energy efficiency and carbon emission analysis of hydrogen transport chains based on liquid hydrogen and ammonia [J]. Chemical Industry and Engineering Progress, 2023, 42(3): 1291-1298.
[8]	HU Yafei, FENG Ziping, TIAN Jiayao, HUANG Chong, SONG Wenji. Energy saving simulation and operation economic analysis of fuel driven non-electric heat pump systems [J]. Chemical Industry and Engineering Progress, 2023, 42(3): 1217-1227.
[9]	YU Zhiguo. Intelligent control system of district heating based on fixed structure phase change heat storage module [J]. Chemical Industry and Engineering Progress, 2022, 41(S1): 168-176.
[10]	GU Xubo, LIAO Chuanhua, WANG Changqing. Design optimization of supercritical water oxidation energy recovery system [J]. Chemical Industry and Engineering Progress, 2022, 41(9): 5094-5102.
[11]	WANG Zijie, GU Yujiong, LIU Haochen, LI Changyun. Comparison and analysis of heat-power decoupling technologies for CHP units [J]. Chemical Industry and Engineering Progress, 2022, 41(7): 3564-3572.
[12]	HU Yafei, LYU Jie, HAN Tao, SONG Wenji, FENG Ziping. Performance characteristics for heating of gas engine-driven heat pump system with waste heat recovery at high ambient temperature [J]. Chemical Industry and Engineering Progress, 2022, 41(7): 3553-3563.
[13]	MA Youfu, WANG Ziwen, LYU Junfu. Simulation of off-design performance of an efficient power generation system with cold-ends optimization using hot air recirculation [J]. Chemical Industry and Engineering Progress, 2022, 41(5): 2340-2347.
[14]	ZOU Pengcheng, JIN Guangyuan, LI Zhenfeng, SONG Chunfang, HAN Taibai, ZHU Yulian. Analysis of multi-physical field characteristics in a microwave reactor with a mode stirrer [J]. Chemical Industry and Engineering Progress, 2022, 41(5): 2301-2310.
[15]	LIU Hongyi, YANG Guangxing, YU Hao. Recent advances of electromagnetic induction heating for sustainable catalytic technology [J]. Chemical Industry and Engineering Progress, 2022, 41(3): 1440-1452.

Comparative analysis of energy efficiency and economy of CO₂ transcritical heat pump system under heating condition

CO₂跨临界热泵系统采暖工况下能效和经济对比分析

RichHTML

PDF (PC)

Knowledge

Abstract

Cite this article

share this article

Figures/Tables 18

References 24

Related Articles 15

Recommended Articles

Metrics

Comments