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以北京某建筑为研究对象,建立太阳能相变蓄热地面辐射供暖系统,对系统热负荷、相变蓄热地板、集热器、电辅助加热器进行设计计算。以TRNSYS软件中的典型年1月为模拟时间,在相同运行策略下,对太阳能相变蓄热地面辐射供暖系统、太阳能地面辐射供暖系统(未设置相变材料层)的室内温度进行仿真模拟。最冷月1月两种系统均在大部分时间保证室内温度大于等于18℃。采用太阳能相变蓄热地面辐射供暖系统时,室内平均温度为19.13℃。采用太阳能地面辐射供暖系统时,室内平均温度为18.53℃。太阳能相变蓄热地面辐射供暖系统的热舒适性略高。 相似文献
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《建筑热能通风空调》2016,(6)
以一种壳管式相变储能单元为研究对象,其中石蜡作为相变材料,水作为换热流体,综合考虑蓄热过程中的显热储能和潜热储能过程,通过Simulink集成了动态储能过程模型并对其进行求解,将模拟结果分别与文献的模拟和实验结果进行对比,表明显热储能过程模拟结果和模拟结果的出口温度平均误差为1.83%;潜热储能过程模拟结果和实验结果的出口温度和融化程度平均误差分别为:0.70%和3.66%。本文使用相变材料的出口温度、充能完成时间、液相百分比和储能速率作为研究系统的性能指标,并模拟仿真不同换热流体进口温度和质量流量对系统性能的影响,换热流体进口温度从75℃增加到90℃,充能完成时间减少了37.6%,储能速率平均增加了63.3%;质量流量从0.07 kg·min-1增加到0.22 kg·min-1,充能完成时间减少了27.5%,预热阶段储能速率随着质量流量的增加而增加,相变潜热蓄热阶段质量流量对储能速率的影响不是很明显,过热阶段储能速率随着质量流量的增加而减少。 相似文献
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建立了板式地板辐射供暖的二维稳态传热模型。采用有限元分析软件ANSYS,分析了地板表面温度分布、传热计算单元内部温度分布、地板表面热流密度的影响因素及地板表面平均温度的影响因素,在考虑地板向下传热时对模拟计算结果进行了修正。供、回水平均温度是影响地板表面热流密度和平均温度的主要因素。当室内温度为20℃时,在维持适宜的地板表面平均温度范围24~28℃的前提下,供、回水平均温度的变化范围为27~34℃,考虑地板向下传热后,应控制在30~35℃。考虑地板向下传热后,应将模拟计算结果乘以一个不小于0.9的修正系数。 相似文献
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长期以来,北方地区采暖以燃煤为主.对城市环境造成了较大的污染。而太阳能作为一种清洁的可再生能源.分布范围广,取之不尽,用之不竭。 相似文献
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The technical feasibility of an innovative solar collector is studied in this paper. A phase change material (paraffin) is
used in the solar collector to store solar energy. This type of system combines both collection and storage of thermal energy
into a single unit. The major advantages of the phase change stores are their large heat storage capacity and isothermal behavior
during the melting and solidifying processes. A negative aspect of paraffin is its low thermal conductivity which increases
the melting and solidifying time for paraffin energy storage. In this paper, new aluminum foams infiltrated with paraffin
are presented. It presents a two dimensional model describing the melting and solidifying processes of paraffin while accounting
for both phase change heat transfer and natural convection. Apparent heat capacity method was used to simulate the melting
and solidifying processes of paraffin. The simulation results show that the motion of the hot liquid paraffin plays an important
role in increasing the heat transfer between paraffin and top surface of solar collector. The shape profile of the pure paraffin
solid-liquid interface is determined by the synergistic relationship between its temperature and velocity field. Though aluminum
foams impregnated with paraffin will limit motion of the hot liquid paraffin, the heat transfer ability is greatly improved.
The distributions of the temperature in the paraffin with aluminum foams are more homogeneous compared with that of the paraffin
without aluminum foams. Thus, use of aluminum foams infused with paraffin improves heat transfer and enhances paraffin’s melting
and solidifying rates. 相似文献
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This paper describes the numeric model developed to simulate heat transfer in phase change materials (PCM) plunged in water tank storage. This model, based on the enthalpy approach, takes into account the conduction and the convection into PCM as well as at the interface between PCM and water of the storage. Furthermore, hysterisis and subcooling are also included. This model has been implemented in an existing TRNSYS type of water tank storage. It allows the simulation of a water storage tank filled with PCM modules made of different materials and different shapes such as cylinders, plates or spheres bed. Comparisons between measurements and simulations has been undertake to evaluate the potential of this model. 相似文献
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The exact 2-D transient solution of a slab with an embedded array of parallel circular pipes for heating/cooling is developed.
The boundary and initial conditions are: constant temperature at the pipe surface, upper slab surface subjected to convection
heat transfer, thermal insulation at the slab bottom, and constant initial temperature. The analytical solution of the transient
bi-dimensional problem is obtained together with the fluid temperature. A calculation example is analysed at the end of the
paper to enlighten practical issues appearing in the computation of the analytical solution. 相似文献