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定形相变贮能式地板辐射采暖系统的实验研究 总被引:8,自引:2,他引:8
作者在北京采暖季节对相变贮能式地板辐射采暖系统进行了实验研究。该系统采用厚度为2cm,熔点和潜热分别为21.6℃和37J/g的定形相变材料。作为比较,也对普通地板采暖系统进行了对比实验研究,发现:相变贮能式地板辐射采暖系统在实验期间基本上每天开启8~10h,在维持室内温度高于对比试验的情形下,运行费用低于对比试验中的普通地板采暖系统。此外,由于相变材料具有较好的贮热能力,电加热系统的启停造成的室内温度波动较小,变化平缓;试验房间内各壁面温度较高,且波动很小,从而提高了室内的平均辐射温度,这也是地板辐射采暖舒适和节能的原因之一。 相似文献
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太阳能地板辐射采暖系统的实验与数值模拟分析 总被引:1,自引:0,他引:1
介绍了上海交通大学太阳能实验室的太阳能地板辐射采暖系统的实验情况,通过实验对该系统在连续循环运行模式下对室内热环境所产生的影响进行了研究,并与非采暖房间进行了比较。同时对整个采暖系统建立了数学模型,通过数值计算得到地板表面温度及室内空气温度动态变化,模拟结果与实验基本吻合。 相似文献
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低温地板辐射采暖系统中辐射板布置方式的优化 总被引:2,自引:0,他引:2
低温地板辐射采暖系统作为一种既节能又舒适的新型采暖方式,国内外对其节能性和节能能力进行了相当多的研究,但对如何进行低温地板辐射采暖系统优化设计的研究很少,本文基于热网模型.利用数值模拟,在等舒适度情况下对不同的辐射板的布置方式(周边布置和中心布置)和辐射板铺设位置的情况下的能耗进行分析,并进一步对如何优化辐射板铺设位置进行了探讨,从而可为低温热水地板辐射采暖系统的优化设计提供参考。 相似文献
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为了提高空气源热泵地板辐射采暖系统的供暖效率,将导热能力极强的热管用于空气源热泵地板辐射采暖系统并对其进行了优化实验。该实验是在热管管间距为15 cm时,对50 cm x 50 cm x 40 cm的房间模型的地板进行加热,分别测试了热源温度为40、45和50℃时,混凝土板块的温度和房间模型的温度,并研究了混凝土板块和房间模型的供暖效果。经过比较分析,得出随着热源温度的升高,供暖效果提高,且热源温度为45℃和50℃能达到相似的效果。在实际应用中,对于该系统,选择合适的热源温度尤为重要。 相似文献
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基于计算机仿真的低温地板辐射采暖系统的节能性分析 总被引:2,自引:2,他引:0
介绍了基于空间热网模型的采暖系统的计算机仿真程序,并运用该程序对低温地板辐射采暖和对流采暖两种系统进行计算机仿真,通过对一个采暖日内两种采暖方式下房间的采暖负荷、室内平均空气温度和维护结构内表面温度的动态分析和比较,证明了在维持房间相同热舒适度的情况下,低温地板辐射采暖系统的采暖负荷比对流采暖系统的采暖负荷小,具有节能性。 相似文献
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Yushi Liu Kunyang Yu Mingjun Xie Shuang Lu Yingzi Yang Hui Wang Hanxi Jia 《国际能源研究杂志》2020,44(7):5791-5805
This work presents a novel eutectic hydrate salt/self-curing acrylic resin form-stable phase change materials (PCMs) composite (EHS/SCR) with favorable form-stable performances for heat energy storage. Further, to improve the surface stability, latent heat and thermal conductivity of the EHS/SCR particles, graphene oxide (GO) used as cladding materials is incorporated onto the surface of the EHS/SCR particles to prepare the GO modified EHS/SCR phase change composite (EGO). The obtained results indicate that the GO-targeted absorption model has achieved the enhancements in stability and thermal properties of EHS/SCR while making use of GO in an efficient and economical way. To be specific, with the introduction of GO of only 1.07 wt%, the thermal conductivity of 0.508 W/m·K is achieved, the value shows a significant rise of 128.6% compared with the EHS/SCR of 0.222 W/m·K. Additionally, the maximum latent heat of EGO-6 is up to 90.4 J/g, which exhibits a 3.19-fold increase compared against that of the uncoated EHS/SCR. Moreover, the prepared EGO composite PCM remain a good thermal cycling reliability after 300 thermal cycles. This work provides a novel opportunity to improve the performance of form-stable PCM composites with an intelligent manufacture-oriented pattern. 相似文献
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Fatty acid/poly(methyl methacrylate) (PMMA) blends as form-stable phase change materials for latent heat thermal energy storage 总被引:6,自引:0,他引:6
Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA), and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the most drawback which limits the utility area of them in thermal energy storage. The use of fatty acids as form-stable PCM will increase their feasibilities in practical LHTES applications due to reduced cost of the energy storage system. In this regard, a series of fatty acid/poly(methyl methacrylate) (PMMA) blends, SA/PMMA, PA/PMMA, MA/PMMA, and LA/PMMA were prepared as new kinds of form-stable PCMs by encapsulation of fatty acids into PMMA which acts as supporting material. The blends were prepared at different mass fractions of fatty acids (50, 60, 70, 80, and 90% w/w) to reach maximum encapsulation ratio. All blends were subjected to leakage test by heating the blends over the melting temperature of the PCM. The blends that do not allow leakage of melted PCM were identified as form-stable PCMs. The form-stable fatty acid/PMMA (80/20 wt.%) blends were characterized using optic microscopy (OM), viscosimetry, and Fourier transform infrared (FT-IR) spectroscopy methods, and the results showed that the PMMA was compatible with the fatty acids. In addition, thermal characteristics such as melting and freezing temperatures and latent heats of the form-stable PCMs were measured by using differential scanning calorimetry (DSC) technique and indicated that they had good thermal properties. On the basis of all results, it was concluded that form-stable fatty acid/PMMA blends had important potential for some practical LHTES applications such as under floor space heating of buildings and passive solar space heating of buildings by using wallboard, plasterboard or floor impregnated with a form-stable PCM due to their satisfying thermal properties, easily preparing in desired dimensions, direct usability without needing an add encapsulation and eliminating the thermal resistance caused by shell and thus reducing cost of LHTES system. 相似文献
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The aim of this research is to prepare of a novel form-stable composite phase change material (PCM) for the latent heat thermal energy storage (LHTES) in buildings, passive solar space heating or functional fluid by entrapping of SA into PMMA cell through ultraviolet curing dispersion polymerization. The composite PCM was characterized using scanning electron microscope (SEM) and Fourier transformation infrared (FT-IR) analysis technique. The results show that the form-stable microencapsulated PCM with core/shell structure was formed and the maximum encapsulated proportion of SA in the composite was 51.8 wt.% without melted PCM seepage from the composite. In the shape stabilized microencapsulated PCM, the polymer acts as supporting material to form the microcapsule cell preventing the leakage of PCM from the composite and the SA acts as a PCM encapsulated in the cell of PMMA resin. The oxygen atom of carbonyl group of skeleton is interacted with the hydrogen atom of hydroxyl group of SA. Thermal properties, thermal reliability and heat storage/release performance of the composite PCM were determined by differential scanning calorimetry (DSC), FT-IR and thermal cycling test analysis. The melting and freezing temperatures and the latent heats of the composite PCM were measured as 60.4 °C, 50.6 °C and 92.1 J/g, 95.9 J/g, respectively. The results of DSC, FT-IR and thermal cycling test are all show that the thermal reliability of the composite PCM has an imperceptible change. This conclusion indicates that the composite has a good thermal and chemical stability. 相似文献
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The halogen-free flame retardant form-stable phase change materials (PCM) based on paraffin/high density polyethylene (HDPE) composites were prepared by using twin-screw extruder technique. The structures and properties of the form-stable PCM composites based on intumescent flame retardant system with expandable graphite (EG) and different synergistic additives, such as ammonium polyphosphate (APP) and zinc borate (ZB) were characterized by scanning electronic microscope (SEM), thermogravimetric analyses (TGA), dynamic Fourier-transform infrared (FTIR) spectra, differential scanning calorimeter (DSC) and Cone calorimeter test. The TGA results showed that the halogen-free flame retardant form-stable PCM composites produced a larger amount of charred residue at 700 °C, although the onset of weight loss of the halogen-free flame retardant form-stable PCM composites occurred at a lower temperature due to the thermal decomposition of flame retardant. The DSC measurements indicated that the additives of flame retardant had little effect on the thermal energy storage property, and the temperatures of phase change peaks and the latent heat of the paraffin showed better occurrence during the freezing process. The dynamic FTIR monitoring results revealed that the breakdowns of main chains (HDPE and paraffin) and formations of various residues increased with increasing thermo-oxidation temperature. It was also found from the Cone calorimeter tests that the peak of heat release rate (PHRR) decreased significantly. Both the decrease of the PHRR and the structure of charred residue after combustion indicated that there was a synergistic effect between the EG and APP, contributing to the improved flammability of the halogen-free flame retardant form-stable PCM composites. 相似文献
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Capric-myristic acid/vermiculite composite as form-stable phase change material for thermal energy storage 总被引:2,自引:0,他引:2
Ali Karaipekli 《Solar Energy》2009,83(3):323-332
Phase change materials (PCMs) can be incorporated with building materials to obtain novel form-stable composite PCM which has effective energy storage performance in latent heat thermal energy storage (LHTES) systems. In this study, capric acid (CA)-myristic acid (MA) eutectic mixture/vermiculite (VMT) composite was prepared as a novel form-stable PCM using vacuum impregnation method. The composite PCM was characterized using scanning electron microscope (SEM) and Fourier transformation infrared (FT-IR) analysis technique. Thermal properties and thermal reliability of the composite PCM were determined by differential scanning calorimetry (DSC) analysis. The CA-MA eutectic mixture could be retained by 20 wt% into pores of the VMT without melted PCM seepage from the composite and therefore, this mixture was described as form-stable composite PCM. Thermal cycling test showed that the form-stable composite PCM has good thermal reliability and chemical stability although it was subjected to 3000 melting/freezing cycling. Thermal conductivity of the form-stable CA-MA/VMT composite PCM was increased by about 85% by introducing 2 wt% expanded graphite (EG) into the composite. The increase in thermal conductivity was confirmed by comparison of the melting and freezing times of the CA-MA/VMT composite with that of CA-MA/VMT/EG composite. The form-stable PCM including EG can be used as energy absorbing building material such as lightweight aggregate for plaster, concrete compounds, fire stop mortar, and component of interior fill for wallboards or hollow bricks because of its good thermal properties, thermal and chemical reliability and thermal conductivity. 相似文献
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Preparation and characterization of flame retardant form-stable phase change materials composed by EPDM,paraffin and nano magnesium hydroxide 总被引:2,自引:0,他引:2
Paraffin, one of the important thermal energy storage materials, possesses various desirable characteristics (e.g. high heat of fusion, variable phase change temperature, self-nucleating, no phase segregation and low cost), but has low thermal stability and is flammable. In the current study, form-stable phase change materials (PCMs) based on EPDM (supported material), paraffin (dispersed phase change material), nano structured magnesium hydroxide (nano-MH) and red phosphorus (RP) with various compositions were prepared. The self-synthesized nano-MH has a kind of lamellar structure with good dispersal as characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The constructional morphology, thermal stability, latent heat and flame retardant properties of as-prepared form-stable PCM blends were evaluated by using a scanning electron microscope (SEM), thermogravimetric analysis (TGA), a differential scanning calorimeter (DSC) and limited oxygen index (LOI) tester, respectively. The SEM and DSC results show that addition of nano-MH and RP has no apparent negative effect on EPDM/paraffin three dimensional netted structures and latent heat. The TGA curves indicate that inducing the nano-MH into the form-stable PCM blends leads to the reinforcement of thermal stability, increasing the amount of char residuals at 700 °C thereby improving the flame retarding performance. 相似文献
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Thermal performance of PCM thermal storage unit for a roof integrated solar heating system 总被引:2,自引:0,他引:2
The thermal performance of a phase change thermal storage unit is analysed and discussed. The storage unit is a component of a roof integrated solar heating system being developed for space heating of a home. The unit consists of several layers of phase change material (PCM) slabs with a melting temperature of 29 °C. Warm air delivered by a roof integrated collector is passed through the spaces between the PCM layers to charge the storage unit. The stored heat is utilised to heat ambient air before being admitted to a living space. The study is based on both experimental results and a theoretical two dimensional mathematical model of the PCM employed to analyse the transient thermal behaviour of the storage unit during the charge and discharge periods. The analysis takes into account the effects of sensible heat which exists when the initial temperature of the PCM is well below or above the melting point during melting or freezing. The significance of natural convection occurring inside the PCM on the heat transfer rate during melting which was previously suspected as the cause of faster melting process in one of the experiments is discussed. The results are compared with a previous analysis based on a one dimensional model which neglected the effect of sensible heat. A comparison with experimental results for a specific geometry is also made. 相似文献
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为分析相变蓄热装置在充热和放热过程中的热性能,设计并搭建一套相变蓄热供热装置中试实验系统,研究主要运行参数对相变蓄热装置热性能的影响;在此基础上,结合项目案例,对相变蓄热供热系统经济性进行分析。结果表明:相变材料(Phase Change Material, PCM)凝固过程中的传热主要受相变介质内部导热控制;而在其熔化过程中自然对流对传热起重要控制作用;蓄热装置充热速率快于放热速率。提高传热流体流量有助于增强PCM中的热传递,缩短充/放热时间,但蓄热装置内PCM温度分布均匀性有所降低;为降低系统能耗,提高储放热效率,优先选用小流量进行充/放热。该相变蓄热供热项目的动态投资回收期为3.55年,具有良好的经济性。研究结果可对相变蓄热供热系统的设计及应用推广提供参考依据。 相似文献