本文選題：相變蓄熱 + 冷凝熱回收　； 參考：《天津商業(yè)大學》2014年碩士論文

【摘要】：能源與環(huán)境問題隨著經(jīng)濟的迅速發(fā)展和社會的進步日益突出，因此利用新的節(jié)能技術(shù)來提高能源利用率，降低常規(guī)能源消耗是能源實現(xiàn)可持續(xù)發(fā)展的重要措施。由于相變蓄熱材料儲能密度高、安全、經(jīng)濟且性能穩(wěn)定，可以解決能源供應(yīng)在時間與空間上不匹配的問題，對提高能源利用率有很高的研究意義和廣闊的應(yīng)用前景。熱泵技術(shù)的節(jié)能和環(huán)保特點在諸多領(lǐng)域得到廣泛應(yīng)用，在制取生活熱水方面的應(yīng)用也在逐漸收到重視。而當下的熱泵熱水器存在水箱占用建筑空間大，系統(tǒng)運行不平穩(wěn)等缺點，為了改善這些缺點本文將相變蓄熱技術(shù)與熱泵技術(shù)相結(jié)合，研究相變蓄熱式空氣源熱泵冷凝熱回收，優(yōu)化系統(tǒng)運行性能并提高冷凝廢熱利用率。 本文所做的研究工作是以相變蓄熱式熱泵空調(diào)冷凝熱回收系統(tǒng)為對象，結(jié)合相變蓄熱技術(shù)對常規(guī)空氣源熱泵空調(diào)系統(tǒng)進行性能實驗和模擬研究。文中冷凝熱回收系統(tǒng)性能研究均是針對部分冷凝熱回收模式展開的，通過實驗測試與數(shù)值計算的研究方法來對該冷凝熱回收系統(tǒng)的換熱特性進行深入研究，主要研究工作如下： 1、對相變傳熱過程進行熱工特性分析，得出相變蓄熱技術(shù)的特點，以及相變蓄熱箱的傳熱系數(shù)計算式。采用差示掃描量熱法（DSC）對相變材料熱物性參數(shù)進行測定，實驗結(jié)果顯示材料熔點為59℃，凝固點為54.3℃，相變潛熱值為187kJ/kg，從而為后期系統(tǒng)性能的計算提供了理論依據(jù)。 2、對相變蓄熱熱泵空調(diào)系統(tǒng)開展蓄熱特性實驗研究。實驗采用模擬室內(nèi)外環(huán)境工況的方法，對系統(tǒng)進行冷凝熱回收實驗。結(jié)果表明系統(tǒng)平均綜合能效系數(shù)COPt為3.35，平均冷凝熱回收率為20%。同無冷凝熱回收熱泵空調(diào)系統(tǒng)制冷模式下的實驗結(jié)果相比，系統(tǒng)平均綜合能效系數(shù)由原來的2.4提高了約39.6%。從系統(tǒng)性能角度來看，將相變蓄熱技術(shù)與傳統(tǒng)熱泵空調(diào)系統(tǒng)結(jié)合可以提高空調(diào)系統(tǒng)的綜合性能。另外，相變材料在蓄熱箱內(nèi)的熔化情況表明，系統(tǒng)運行至10h，蓄熱箱內(nèi)的石蠟仍存在部分固態(tài)未融化。 3、對相變蓄熱箱內(nèi)石蠟的放熱特性開展實驗研究，通過改變蓄熱箱冷水進口水溫和水流量來對箱內(nèi)石蠟的放熱過程進行了實驗測試。結(jié)果表明，增加水流量或者提高冷水進口水溫可以縮短熱水加熱時間，增大水流量不改變冷水進水溫度，熱水出水時間可以縮短約1.6h；提高冷水進口水溫水不改變水流量，獲取熱水時間縮短約3.3h。同時研究結(jié)果表明，在1h之內(nèi)熱水溫升不大，約為2~3℃，可見換熱效率很低。 4、對相變蓄熱箱內(nèi)換熱過程建立了物理和數(shù)學模型，模擬計算有無自然對流現(xiàn)象的石蠟溫度變化，并將考慮自然對流的計算結(jié)果與實驗進行了比較。結(jié)果表明，模擬計算與實驗結(jié)果近似相同，，誤差在0.3%～7%之內(nèi)，模擬計算有效。在石蠟蓄熱過程中，箱內(nèi)石蠟溫度分層現(xiàn)象較重，最大溫差達到32℃，可見蓄熱箱換熱效果并不理想，系統(tǒng)性能仍需進一步提高。
[Abstract]:Energy and environmental problems with the rapid development of economy and social progress have become increasingly prominent, therefore the use of new technologies to improve energy efficiency, reduce the consumption of conventional energy sources is an important measure to realize the sustainable development of energy. As the phase change material of high energy storage density, safety, economy and stable performance, can solve the energy supply does not match in time and space of the problem, the significance of the research is to improve the energy utilization rate is high and wide application prospect. The characteristics of energy saving and environmental protection heat pump technology has been widely used in many fields, the application in preparation of hot water has also gradually received attention. While the heat pump water heater of the present building space occupied by water tank large system, unstable operation and other shortcomings, in order to improve the shortcomings of the phase-change heat storage technology and heat pump technology combined with the research of phase change thermal storage type air source heat pump cold The condensing heat recovery is used to optimize the operating performance of the system and improve the utilization rate of condensing waste heat.
The work of this paper is to phase change condensing heat recovery heat pump air conditioning system as the object, combined with the phase change technology and simulation experiments of the conventional air source heat pump air conditioning system. In this paper, the performance of the system is on a part of the condensing heat recovery of condensing heat recovery mode, by using the method of test and numerical experiments the calculation of the heat transfer characteristics of the condensing heat recovery system of in-depth study, the main research work is as follows:
1, thermodynamic analysis on the characteristics of phase change heat transfer process, the characteristics of phase change thermal storage technology, and the calculation of phase change thermal storage box. The heat transfer coefficient by differential scanning calorimetry (DSC) of the phase change material thermophysical parameters were measured, experimental results show that the melting point of 59 DEG C, the freezing point is 54.3 DEG C, phase transition the latent heat value is 187kJ/kg, which provides a theoretical basis for the calculation of the late performance of the system.
2, the phase change heat pump air conditioning system to carry out experimental research on the characteristics of the regenerative method. Experiments using simulated indoor environment condition, for condensing heat recovery experiments on the system. The results show that the system average comprehensive energy efficiency coefficient of COPt was 3.35, compared to the average condensation heat recovery rate of 20%. with non condensing heat recovery heat pump air conditioning system under the mode of experiment the average comprehensive energy efficiency coefficient increased from 2.4 about 39.6%. from the performance point of view, the phase change heat storage technology with the traditional combination of heat pump air conditioning system can improve the comprehensive performance of air conditioning system. In addition, shows that the melting of phase change material in the heat storage tank and system operation to 10h, the heat storage tank is still a part of solid paraffin not melt.
3, to carry out the experimental study on heat transfer characteristics of phase change heat storage tank of paraffin, by changing the heat storage tank water inlet water temperature and flow of box paraffin exothermic process was tested. The results showed that the water flow rate increase or improve the cold water inlet water temperature hot water can shorten the heating time, increase the flow of water without changing the inlet temperature of cold water, hot water the time can be shortened about 1.6h; improve the cold water inlet water temperature does not change the water flow, reduce about 3.3h. the results also show that the access time within 1h hot water, hot water temperature is about 2~3 degrees, can see the heat transfer efficiency is very low.
4, the phase change heat transfer process inside a physical and mathematical model, the temperature change has no paraffin simulation of natural convection, and will consider the results of natural convection are compared with experiments. The results show that the simulation and experimental results are approximately the same, the error in the range from 0.3% to 7%, effective simulation in the process of paraffin storage box, paraffin temperature stratification is heavy, the maximum temperature reached 32 degrees, the visible heat storage tank heat transfer effect is not ideal, still need to further improve the system performance.

【學位授予單位】：天津商業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU831

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