冬季寒冷条件下太阳能—空气源热泵热水器的数值模拟

发布时间：2018-01-11 14:07

本文关键词：冬季寒冷条件下太阳能—空气源热泵热水器的数值模拟　出处：《兰州理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：随着我国经济社会的高速发展,能源危机和节能减排的意识日益高涨。建筑能耗占我国社会总能耗的40%以上,建筑节能已经成为节能减排的重点领域,可再生能源辅助的热泵技术研究已经成为热泵研究领域的热点,空气热源和太阳能热源以其资源丰富、清洁无污染等优势在热泵热利用中获得普遍关注。然而,由于太阳能的间歇性和低能量密度,传统空气源热泵在冬季低温条件下系统性能明显下降,因此,空气源热泵或太阳能热泵在我国广大北方地区的推广应用都受到了严重制约。研发经济高效、性能稳定、适用地域广的多能互补热泵系统成为解决这一问题的有效途径。为了利用西北地区丰富的太阳能资源,有效提高空气源热泵热水器在我国西北寒冷地区的热力性能和低温适应性,本课题将直膨式太阳能集热器和空气源热泵的蒸发器在结构和功能上结合起来,提出了一种适合西北寒冷地区的太阳能辅助加热的空气源热泵热水系统,并开展了相关研究。主要的研究内容和结果如下： (1)建立了太阳能辅助空气源热泵热水系统各部件及系统的数学模型并进行了求解。利用稳态分布参数法建立了翅片管换热器、沉浸式盘管冷凝器和蓄热水箱的仿真计算模型,建立了压缩机和热力膨胀阀的集总参数数学模型,建立了制冷剂热力性质计算模型和制冷剂充注量数学模型,联立各部件模型,利用Matlab软件编写了系统的模拟计算程序,迭代求解了整个热泵热水器系统循环。 (2)以上海交通大学郭俊杰博士建立的空气源热泵热水装置在5℃的实验性能为参照,结合兰州地区气象数据,运用系统模拟计算程序研究了空气源热泵热水器在兰州冬季环境温度为－20-5℃时的性能,结果表明：随着环境温度的升高,系统的各项性能得到了改善,制热量迅速升高,压缩机耗功下降,热水加热时间缩短,系统COP明显增大；当环境温度低于－15℃时,蒸发温度过低,制冷剂流量很小,导致系统的COP低于1.6,几乎等同于用电直接制取热水。 (3)设计了一套直膨式太阳能集热器,与空气换热器／蒸发器并联作为太阳能辅助空气源热泵系统的蒸发端,在－20-5℃的环境温度下,取太阳能辐射强度分别为200W/m2、500W/m2、700W/m2,研究太阳能辅助空气源热泵热水系统的性能,结果表明：系统的制热量随环境温度和太阳能辐射强度的升高而增大,太阳能和空气双热源热泵系统的制热量明显大于单独空气源热泵系统的制热量,而且随着太阳能辐射强度的增大而增大；压缩机功率随环境温度和太阳辐射强度的升高略有升高,但变化不大；随着太阳辐射强度和环境温度的升高,系统COP明显升高,热水加热时间△τ不断减少。 (4)研究了设定工况下系统把水从15℃加热到55℃的过程中太阳能、空气热能以及压缩机耗功各自的贡献率,即能量的输入份额,结果表明：当太阳辐射强度一定时,随着环境温度的升高,太阳能和空气热能所输入的能量份额逐渐上升,而压缩机耗电量逐渐减小：随着太阳辐射强度的增大,太阳能输入的能量份额增大,空气热能输入的能量份额减小,压缩机耗电量输入份额减小。 (5)与传统能源热水器(燃气热水器、燃煤热水器、电加热热水器)相比,制取相同量的热水,单独空气源热泵热水器和太阳能辅助空气源热泵热水器经济性都明显优于电加热热水器；当环境温度高于－5℃时,空气源热泵热水器和太阳能辅助空气源热泵热水器比燃气热水器节能,随着环境温度的升高,系统的能耗越少,经济性越明显；环境温度高于－20℃时太阳能辅助空气源热泵热水器也明显比燃气热水器和燃煤热水器更节能,并且随着环境温度的升高系统耗电量和电费越少；太阳能辅助空气源热泵热水器的经济性和节能性明显优于单独空气源热泵热水器；当环境温度为0℃时,制取相同量的生活热水,太阳能辅助空气源热泵热水器分别比天然气、标准煤、电能和单独空气源热泵热水器节能50.4%,53.7%,82.1%,42.8%；随着各能源价格的上涨,太阳能辅助空气源热泵热水器具有较高的经济竞争优势。本课题的创新性在于研发了一套适合冬季寒冷地区使用的太阳能辅助的空气源热泵热水系统,并研究了其－20-5℃环境温度下的性能,改善了单独空气源热泵系统在寒冷气候条件下的制热性能,为该系统在西北地区的推广和应用提供了理论依据。研究过程中,本课题得到了国家863计划课题(2013AA051601)、国家科技支撑计划课题(2011BAD15803)、国家自然科学基金项目(51266005)、教育部科学技术研究重点项目(1106ZBB007)、甘肃省杰出青年科学基金项目(2012GS05601)、甘肃省教育厅项目(0803-06)、甘肃省建设科技攻关项目(JK2010-29)以及兰州理工大学“红柳杰出人才计划”(Q201101)等项目的联合资助。
[Abstract]:With the rapid development of China's economy and society, energy crisis and rising awareness of energy saving and emission reduction. The building energy consumption accounted for 40% of total energy consumption in our society, building energy efficiency has become the key areas of energy saving, renewable energy assisted heat pump technology research has become a hot research field of heat pump, air source and solar heat source to the the advantage of rich resources, clean and pollution-free won widespread attention in the use of heat. However, due to the intermittent solar energy and low energy density, the traditional air source heat pump in the system decreased significantly under low temperature in winter can therefore, application of air source heat pump or solar heat pump in the northern region of China was serious restricted. Research and development of economic efficiency, stable performance, multi energy complementary heat pump system has become an effective way to solve the problem for the region wide.
In order to utilize the abundant solar energy resources in the northwest region, effectively improve the air source heat pump water heater in China's northwest cold area thermal performance and low temperature adaptability, the evaporator direct expansion solar heat collector and the air source heat pump combined in structure and function, put forward the air source heat pump hot water system for the northwest cold regions of the solar assisted heating, and carried out related research. The main research contents and results are as follows:
(1) established the mathematical model of each component and system of solar assisted air source heat pump hot water system and solved. A finned tube heat exchanger using steady-state distributed parameter method, immersion coil condenser and the heat storage tank of the simulation model, the lumped parameter models of compressor and thermal expansion valve. The establishment of the mathematical model and mathematical model of the refrigerant filling quantity of refrigerant thermodynamic properties, the simultaneous model of the various components, write the simulation program of the system by using Matlab software, the iterative solution of the heat pump water heater system cycle.
(2) the air source heat pump hot water device established by Dr. Guo Junjie of Shanghai Jiao Tong University in the experimental performance of 5 DEG C for reference, combined with the meteorological data of Lanzhou area, using the system simulation of the air source heat pump water heater for the performance of 20-5 C in the Lanzhou winter temperature calculation program. The results show that with the increase of environmental temperature, the the performance of the system is improved, the heat rises rapidly, compressor power consumption decreased, heating time is shortened, COP increased significantly; when the environment temperature is below 15 DEG C when the evaporation temperature is too low, the refrigerant flow is very small, resulting in the COP less than 1.6, almost equivalent to electricity directly by hot water.
(3) a direct expansion solar collector was designed, and the air heat exchanger / parallel evaporators as solar assisted air source heat pump system in evaporation end, 20-5 at ambient temperature, solar radiation intensity were 200W/m2500W/m2700W/m2, auxiliary performance research of solar air source heat pump hot water system, help the results show that the increase of heating system with environmental temperature and solar radiation intensity increases, the heating system of solar energy and air heat dual heat source heat pump system was higher than that of the air source heat pump systems, and increases with the solar radiation intensity increases; the compressor power with the ambient temperature and solar radiation intensity increased slightly increased, but the change is not significant; with the increase of solar radiation intensity and ambient temperature, COP increased significantly, hot water heating time decreasing. Delta tau
(4) on the condition of the water system set from 15 C to 55 C of the solar heating process, power consumption and heat air compressor respective contribution rate, namely the input energy share, the results showed that: when the solar radiation intensity, with the increase of environmental temperature, solar energy and air heat energy input. The share increased gradually, while the compressor power consumption decreases gradually with the increase of the intensity of solar radiation, solar energy input share increases, the air heat input energy share is reduced, the power consumption of the compressor input share decreases.
(5) with conventional energy water heater (coal gas water heater, water heater, electric water heater) compared to produce the same amount of hot water, separate air source heat pump water heater and solar assisted air source heat pump water heater economy are obviously better than the electric water heater; when the environment temperature is higher than 5 DEG C, air source heat pump water heater and solar assisted air source heat pump water heater, gas water heater energy ratio, with the increase of environmental temperature, the energy consumption of the system is less, the economy is more obvious; the environment temperature is higher than from-20 DEG when solar assisted air source heat pump water heater is also significantly higher than the gas water heater and water heater burning more energy, and with the environment temperature increasing system power consumption and electricity less; solar assisted air source heat pump water heater economy and energy efficiency is obviously better than the single air source heat pump water heater; when the ambient temperature is 0 degrees centigrade for The same quantity of hot water, solar assisted air source heat pump water heater respectively than natural gas, coal, electricity and air source heat pump water heater energy saving 50.4%, 53.7%, 82.1%, 42.8%; with the rising energy prices, solar assisted air source heat pump water heater has high economic competitive advantage.
The innovation of this paper is to develop a set of suitable for cold air source heat pump hot water system of solar assisted area used in winter, and study the performance of the 20-5 at ambient temperature, heating to improve the performance of individual air source heat pump system in cold climates, and provides a theoretical basis for the popularization and application of this the system in the northwest region.
In the process of research, this dissertation is supported by the National 863 Project (2013AA051601), National Science and technology support program (2011BAD15803), the National Natural Science Fund Project (51266005), the Ministry of Education Science and technology research projects (1106ZBB007), Gansu Province outstanding youth science fund project (2012GS05601), Gansu Provincial Department of education project (0803-06) Gansu Province, the construction of key projects of science and Technology (JK2010-29) and the Lanzhou University of Technology tamarisk outstanding talent program (Q201101) jointly funded projects.

【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU822

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