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工业企业、公用事业等许多领域内,多种设备、设施需要保温。然而由于当今保温技术的水平所限,得不到无限大热阻的保温材料,热量总是要散失的。过度的热量散失一般都要导致严重的后果。例如管内输送的石油,因热量的散失,温度降低,粘度增加。在输量一定的情况下,粘度越大摩阻越大。因此因保温护层破损、裂纹等因素造成保温失效时,直接影响是热能的散失,间接 相似文献
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通过对胜利油田桩西联合站进行实地调研,把握原油处理和污水处理的主要工艺流程、设备性能及效率、供能设施及燃料消耗、来液及外排流体性质。通过能量结构分析寻找关键耗能环节和系统的用能薄弱环节,确定出系统最大的节能潜力在于减少罐体热量散失和污水携带的能量损失。针对桩西联合站的实际生产状况,提出在不影响生产的前提下利用岩棉对罐体进行保温减少热量散失的节能措施,经计算保温后罐体的热量散失仅为原来的1/3。针对油田污水直接回注地层大量热能浪费的问题,论证了利用吸收式热泵技术进行污水余热回收的可行性,回收的能量可以用于站内生活用能,也可以直接用于集输系统供热,若用热泵代替加热炉供热,则可减少将近1/2的天然气消耗量,并且极大地降低了加热炉的烟气排放,对减轻大气污染具有积极作用。 相似文献
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分体太阳能热水系统的保温效果好,热量损失小,集热效率高。在运行过程中,如果长时间停止使用热水,会导致储水箱水温过高。集热器长期在高温状态下工作,可能造成一些非金属部件损坏。另外,水的温度高,易形成水垢,不利于系统的运行。如果储水箱为封闭式承压水 相似文献
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为了更大程度利用现有集中空调水冷冷水机组,提出在过渡季节或温度较高的冬季采用冷却塔辅助供热的方案,并对叉流填料塔辅助供热系统性能进行实验测试。实验结果表明:提高空气流量有助于提高塔内进出口水温差进而提高系统换热量;提高水流量能提高系统换热量,但换热温差降低。将进回水温差和进口空气湿球温度与进口水温的差的比值定义为填料的温升效率,发现其随空气流量和水流量的变化而变化,但与进口水温无关。在进水流量为0.11kg/s,进口空气流量为0.19kg/s时,填料的温升效率为47.7%,从实验的角度分析了填料塔辅助供热的可行性。 相似文献
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以长春某数据机房电力室为基础,通过对房间余热量、送排风量及湿式水膜耗水量的计算,提出针对这种高发热量、低散失量的环境采取的空调方案,为数据机房这种特殊要求的空间提供了解决的办法。 相似文献
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答:目前我国农村量大面广的195和190型单缸柴油机均采用蒸发式水箱的冷却方式。这两种机型有一个与机体直接相连的水箱,冷却水最高温度允许达100℃,并自行蒸发。由于没有水泵、风扇和附属管路,因而结构简单。但在柴油机工作中,水箱不允许长时间处于缺水状态,以免机体过热而使机件膨胀、润滑条件变差,这样容易发生烧尼拉缸而引发大事故。而若水温过低,则会由冷却水散失热量过多而降低柴油机的动力性与经济性。为此,对这种冷却系统应特别注意以下几点:a.起动前,应先给水箱加注热水,以预热机体;起动后,先低速空转一会,待水温升… 相似文献
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针对大型渡槽施工期间常见裂缝问题,采用三维有限元仿真分析软件,以南水北调某大型渡槽为例,对混凝土浇筑全过程进行了模拟,分析了一期水管冷却效果,并对水管冷却的通水温度进行敏感性分析.计算结果表明,水管冷却具有良好的导热降温作用,不同的通水温度对混凝土温度降幅基本一致,在确保降温效果的同时可适当提高通水温度以降低水管附近混凝土的拉应力,同样能有效防止施工早期和后期其他部位出现温度裂缝,可供类似工程在施工期的温控措施借鉴. 相似文献
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对一台家用空气源热泵热水器进行冬季性能测试,研究室外空气温度、水箱温度不同时机组性能变化。基于测试数据分析影响机组性能的敏感因素,依据所得天津地区实测数据分析其冬季平均能效。结果表明:COP 最低为1.30,具有节能效果;保证用水舒适度及机组运行稳定的情况下,45 ℃为水箱最佳设定温度;室外空气温度偏移较水箱平均温度偏移对系统性能更敏感;测试工况下热泵机组单独工作和启动电辅加热时全冬季的平均能效相差甚微,若用户设定机组在日最高温度时段开启加热,能获得更好的节能效果。 相似文献
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An unsteady state theoretical model has been developed to predict the humidity ratio and temperature of the air - water capour mixture in greenhouses. Predicted values are verified by measurements. The relative contribution of condensation heat loss to the total heat loss during cold winter operation is investigated. 相似文献
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It is proposed to use an artficial lake, thermally insulated in the upper part only, to be filled during the spring, summer and autumn with hot water at 98°C, as a big storage of heat. Both the lake and the solar collectors should be placed in the mountains in order to exploit the low cost of the land and the higher solar radiation. An aqueduct with a low cost thermal insulation and with a negligible temperature drop even with 100 km length, can heat a city with more than 1 million people. In order to extract the maximum heat from the water, the aqueduct first feeds usual heaters then, in cascade, radiating panels and finally warm air conditioners equipped with a heat pump so that the discharged water is at 5°C. Convenient solar collectors to be placed in the mountains and for large production of hot water are the ones with concentration by fixed cylindrical mirrors. The design of the relevant moving tubular boiler is presented. The estimated cost per person is half of the cost required by a conventional heating system. 相似文献
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Lianying Zhang Min Zhou Chunfang Yang Yuefei Li Zhibo Fu Juanfang Wang Liwen Jin 《国际能源研究杂志》2020,44(12):9399-9413
Using high-temperature heat pump technology to recover waste heat of circulating cooling water in a steel plant for central heating system not can only reduce the temperature of circulating cooling water to meet the needs of smelting process but also can save energy and protect environment as well as bring great economic benefits to steel plant that can sell heat to the heat users. The energy consumption equation of heat pump central heating system was established based on the energy consumption of heat pump, energy consumption of water pump, and heat loss. The optimal inlet water temperature, inlet flow rate, and the number of operating heat pump modules at different outdoor temperatures were calculated by genetic algorithm. The superiority and operating control strategy of heat pump central heating system were discussed. The results show that with the increase of outdoor temperature, the optimal inlet flow rate and the number of operating heat pump module decrease. However, the inlet water temperature almost does not change. It is more suitable for the heat pump central heating system to change the inlet flow and the number of operating heat pump modules. The operating control strategy equation was established by linear fitting, which provides guidance for the engineering application of heat pump central heating system. 相似文献
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随着环境的变化,热泵热水机将出现冬季结霜,夏季出现低压压力过高的现象。文章对风冷热泵热水机组在运行时压力、温度变化情况进行分析,对机组制热量偏离设计要求的原因进行了分析,并给出三种合理的方法,最后得出最佳的方案。结合实验结果证明了经过改进后稳定性得到改善。 相似文献