Research On Dynamic Character Of Open-loop System Surface Water Source Heat Pump System

With the high-speed development of industry and economic as well as energy and environmental issues have become increasingly prominent in china, the surface-water source heat pump (SWHP) draws more and more public attention. China has rich surface water resources. Especially,the Yangtze River district and the south of China abound with water resources, the surface-water source heat pump possess great significance.At present,many surface water source heat pump systems using lakes,ponds, rivers and reservoirs has come into use in our country.Most of them are open-loop surface water heat pumps. As the limitation of theoretical knowledge and practical experience successful, various problems come into when systems are in the actual operation ,and the the bad performance of these systems in energy saving respect turns out. For motionless water,two major factors which cause the system is not energy- saving are water temperature,water quantity and energy consumption of water intake. Judging a surface water source heat pump system is energy-saving or not, should consider the optimal coupling value of water temperature and energy consumption of water intake. For running water, the major factor which causes the system is not energy-saving is the program of water intake which includes lift of water intake and mode of water intake.This paper bases on superficial water (4 ~ 10m) as the research object, Primarily aim at open-loop lake water heat pumps. Dynamicly analysis and research their operational characteristics. The main research contents are:①Aimed at superficial and motionless water, based on N-S equations, dynamic two-dimensional model of lake water used for lake-water source heat pump system was built using temperature equation mass equation and energy equation.And arithmetic solution of wate temperature was attained by coupled solution.②Based on the dynamic two-dimensional model of lake water temperature and annual hourly load value, the water temperature in dynamic changes were calculated using hourly parameters and average parameters separately. The conclusion was obtained that average load parameters make little attention on the calculation results of temperature.Meteorologic parameter make more attention on the calculation results of temperature.So, suggestion is that hourly meteorologic parameters should be used in the analysis and research of dynamic water temperature.③The ynamic changes of water temperature in winter was got using hourly meteorologic parameters and average load parameters.Based on limit temperature of water abstraction in winter,The largest quantity of cold the water can carried was obtained in different load and different start water temperature in heating period. Through regression, heat carrying capacity of water was obtained. And test the reliability of results through the practical engineering.④Based on the climatic conditions in chongqing area, The influences of rainfall on water temperature distribution and heat carrying capacity of water were analyzed respectively. Through the analysis on the efficiency of rainfall on operational energy of water source heat pump systems, the conclusion was obtained that heavy rain makes temperature decrease by the way of inputing cold energy.The average energy efficiency ratio of unit before and after the rainfall ware 3.29 and 4.35 in measurement, and system efficiency had improved 32.3% than clear day before the rainfall. Light rain and shower make the temperature of upper and lower of water tends to be uniform by perturbation, which make little influence on the operational energy of the unit,but speed up temperature rise of water supply layer(bottom layer of water).Finally, when making analysis of efficiency of open-loop lake water source heat pump systems, local climatic conditions should be considered fully.⑤As for open-loop surface water heat pumps, energy consumption of water abstraction is the key factor for energy Saving of system. Energy efficiency ratio model of open-loop surface water source heat pump system is established on the basises of energy consumption model of energy consumption model of heat pump unit and water abstraction.Based on energy saving rate and Regulation of energy consumption of water abstraction, dynamic limit temperature of water abstraction in different water supply temperature of cooling tower and different pump head was been calculated .Calculation method of limit temperature of water abstraction of open-loop surface surface water heat pumps was been established. Moreover, energy saving rate of surface water source heat pump system relative to traditional air-conditioning system was been calculated in different condition.⑥Based on the practical project in Chong qing, detailed analysis were done on the lake water source heat pump system, and analysis the heat capacity of the artificial lake, point out its shortages in design and operation and make suggestions for improvement measure.Other projects can use for a reference.