| 摘要: |
| 中央空调冷冻水系统大温差设计可以显著降低输配能耗，对系统节能具有重要意义。但随设计温差增大、冷冻水流速降低，蒸发器水侧传热系数逐渐减小，成为制约冷水机组能效的主要因素。本文基于蒸发器换热机理，理论分析了冷冻水大温差对蒸发器换热性能的影响，并通过离心式冷水机组串联运行的方案，实验对比了大温差工况下不同水路流程对整机性能的影响。结果表明：在冷冻水10 ℃大温差设计工况下，采用蒸发器双流程串联的设计方法，相比于单流程方案能效可提升6%；而得益于串联方案中间温度的存在，上下游机组在负荷占比为55%：45%时，整机能效达到最佳。 |
| 关键词: 离心式冷水机组 冷冻水系统 大温差 串联 能效 |
| DOI： |
| 投稿时间：2021-01-04 修订日期：2021-03-31
|
| 基金项目:国家重点研发计划资助（2018YFC0705000）。 |
|
| Experimental Research on Design and Operation Characteristics of Large Temperature Difference Centrifugal Chiller |
| Zhou Yu,Zhuo Mingsheng,Zhang Longai |
| (State Key Laboratory of Air-conditioning Equipment and System Energy Conservation; GREE Electric Appliances, INC. of Zhuhai) |
| Abstract: |
| Chilled water systems with large temperature differences are important for the design of energy-saving heating, ventilation, and air-conditioning systems, as they can reduce the energy consumption of chilled water pumps. However, the water-side heat transfer coefficient of the evaporator gradually decreases as the design temperature difference increases, and the chilled water flow rate decreases. This has become the main factor limiting the energy efficiency of chillers. In this study, the effect of the large temperature difference on the heat transfer performance of the evaporator is analyzed theoretically according to the heat transfer mechanism of the evaporator. The influence of different water circuit passes on the performance of centrifugal chillers designed with large temperature differences was compared experimentally in which the chillers were run in series. The results showed that, under the design conditions of a 10 ℃ temperature difference, the efficiency of the chillers in series can achieve a 6% improvement when the evaporators use dual passes rather than a single pass. The efficiency of the whole unit is optimized when the load proportion of the upstream and downstream units is approximately 55%:45%, owing to the intermediate temperature of the series scheme. |
| Key words: centrifugal chiller chilled water system large temperature difference in series efficiency |
