共查询到20条相似文献,搜索用时 156 毫秒
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在线源理论的基础上建立了土壤源热泵系统的模拟模型,该模型可以用于土壤源热泵系统的全年运行模拟,预测土壤源热泵系统的能耗情况;对于土壤源热泵系统的经济性评估,提出了地下换热器换热成本的概念,并导出了地下换热器换热成本的通用计算方法。本文中的模型可以对土壤源热泵系统的设计方案进行经济性评估,以便设计人员选取经济性较好的方案。 相似文献
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一种直热式冷暖空调热水三用机的研究 总被引:5,自引:0,他引:5
介绍了一种由四个分立循环构成的冷暖空调热水三用机的系统流程和工作原理,首次公开了一种热泵用的直热储热两用型热水换热器的基本结构,工作原理,用实验和数值模拟方法,研究了这种新型换热器在零出水量作储热式换热器和在有不同出水量以及定温出水时的换热性能,并比较了同传热面积的浸泡式盘管换热器的性能.研究表明,带导流套筒的新换热器与市场上的家用热泵热水器的浸泡式盘管换热器相比,在连续供热水时,换热能力高1倍多,在零流量静态加热时,换热能力高10%以上. 相似文献
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基于地源热泵地埋管换热器钻孔内准三维传热模型和钻孔外有限长线热源模型,采用温度叠加原理,编写地下换热系统计算程序,通过引入管群横截面水力半径的概念,研究了管群不同布置形式对地埋管换热器换热效果的影响。研究结果表明:在匀强交变脉冲热流作用下,当向地下吸热放热平衡时,管群的布置形式对地埋管换热器换热影响不显著;当吸热放热不平衡时,管群的布置形式对地埋管换热器换热影响较大,水力半径小的布置换热效果较好;并推出即使地埋管换热器向地下土壤吸热放热不平衡,只要不平衡率不高,通过设计合理的管群布置形式,单独的地源热泵空调系统依然可以长期正常运行。 相似文献
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分析了混合式地源热泵的控制方法和控制参数。通过试验对比了在相同运行方式下冷却塔与地埋管串、并联时混合式地源热泵的运行结果,得出了基于系统综合效率与热平衡条件下的南京地区较合理的混合式地源热泵连接与运行方式。 相似文献
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Mohammed Awwad Ali Al-Dabbas 《Journal of Mechanical Science and Technology》2011,25(8):2013-2023
Geothermal energy in Jordan is a low-emission and renewable source that could provide households and commercial buildings
with heating and cooling. Access to this ‘free’ energy may be available just a few feet underground. Thus, the objectives
of this research are designing a ground heat exchanger that utilizes geothermal energy in heating to exchange the primary
geothermal fluid with a secondary clean fluid, determining the feasibility of designing a ground heat exchanger system to
pump geothermal energy under the weather conditions of the Ma’en area in Jordan and calculating the amount of energy saved.
The design procedure involves applying energy and momentum equations around the geothermal fluid circuit. The FLUENT software
program is used to calculate the ground heat exchanger parameters and the amount of energy saved. Finally, the feasibility
study shows that the Geoexchange systems represent a savings to homeowners of around 70% in the heating mode, and up to 50%
in the cooling mode compared to conventional fossil fuel systems. 相似文献
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Hakan Demir Ahmet Koyun Ş. Özgür Atayılmaz Özden Ağra Ahmet Selim Dalkılıç 《Journal of Mechanical Science and Technology》2013,27(8):2497-2506
Heat transfer from finned pipes buried in the soil has been investigated using experimental, analytical and numerical techniques. The experimental setup consists of a ground source heat pump system and two separate ground heat exchangers. Constant surface temperature approach based on Carslaw and Jaeger’s theory study was used for calculating the heat transfer from the pipes analytically. The problem was modeled and solved using a CFD program numerically. Effects of the fin number, fin length and simulation time on the heat transfer rate have been investigated and compared with bare tube. A modified analytical formula was also proposed for finned pipes in this study. 相似文献
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Mohammad Hossein Jahangir Seyed Amirodin Sadrnejad 《Journal of Mechanical Science and Technology》2012,26(11):3661-3672
After a spacious research and consideration on various approaches of thermal coupled formulations in porous media, a new mathematical form of coupled heat, moisture, and air transfer in unsaturated soil is proposed upon taking the effect of combined volumetric moisture content and temperature gradients and air pressure changes. In this matter, in the convective flows through the unsaturated heated soil, the effects of sensible and latent heat of vapor are also composed with the water and dry air fluxes. Thus in this aspect, some new material parameters are defined for the derived equations, which are related to thermodynamic specifications of soil and the soil-water characteristic curve. After that, the application of the model is presented with a numerical example of a ground heat exchanger which is buried in the earth vertically. It could be considered as an interior heating source which operates in extracting saved energy from the earth or emitting heat to the ground. Then, by using some thermal graphs, the influence of the different operating ratio is investigated which are compared with the full operating mode at all times. Meanwhile, the mode1 is verified by comparing its results against those established by other researchers. By the results, it was found that the volumetric water content and specific heat capacity are the main factors could be effective to generate directly the thermal and isothermal diffusivities and conductivities in terms of the thermodynamic properties. 相似文献
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地源热泵U型管换热器夏季工况试验分析 总被引:1,自引:1,他引:0
U型管换热器设计是土壤源热泵系统应用的关键,埋管深度、管内流速、土壤初始温度、运行模式等都是影响其性能的主要因素,利用上海地区所建设的不同埋深U型换热器(60m,90m)土壤源热泵试验装置,进行了夏季工况试验,测得热泵运行前土壤初始温度分布;测试了热泵机组间歇和连续运行时换热器的换热情况;还针对不同埋管内冷却水流速,测得到了单位孔深换热量,结果表明增加冷却水流速并不能一味地提高其每延米换热量,埋管内冷却水流速存在一个最佳值。 相似文献