太阳能—空气源复合热泵机组优化设计及性能研究
发布时间：2018-12-17 00:57
【摘要】：节能减排以及能源高效利用在当今能源资源短缺的时代受到极高的关注,建筑能耗中的空调能耗在整个能源消耗总量中所占比重较大,故需通过先进技术改进或系统优化等方式减小空调耗能。空气源热泵是以空气为低品热源,吸收空气中的热量或冷量以达到制热或制冷的目的高效节能换热设备。然而在我国北方寒冷地区,空气源热泵的使用受到限制,当冬季室外温度较低时,由于蒸发器受低温影响出现蒸发温度较低,压缩机排气温度过高,压缩比增大等问题而使热泵不能正常运行,但此时建筑内部的热负荷却随室外温度降低而增大,以至于空调采暖能耗增大。多能源综合利用是解决以上问题的有效办法,例如在空气源热泵的基础上加以太阳能、生物质能等辅助换热。本文采用一种新型太阳能-空气源双热源复合热泵,对室外换热器结构进行优化,迎风侧第一排换热管内走太阳能热水,对进入蒸发器的低温空气进行预热,提高蒸发器蒸发温度。文章针对某品牌60kw-V型空气源热泵进行优化改进,首先对室外机部分流路布置进行优化,然后对未加太阳能热水的室外换热器进行数值模型建立,选取一层翅片作为计算单元,模拟名义工况下每台风机风量以3000m3/h为步长,由9000m3/h增加至18000m3/h时对空气源热泵换热的影响。得出不同风机风量下,换热量随风量的增加而增加,后趋于稳定,室外温度较高时,可采取单一热源空气源热泵进行供热。另外风量越大,空气侧的压力损失越大。针对复合热泵的复合换热器建立数值模型,模拟室外温度分别在名义工况(7℃)、标准工况(0℃)以及以济南为例,冬季室外空调计算温度(-7.7℃)三种工况下,不同风机风量和太阳能热水温度时复合热泵的换热效果。太阳能热水以5℃为步长,由15℃增至30℃,风机风量设置同单独空气源热泵风量设置。结果表示:复合热泵的换热量与COP均高于未加热水时空气源热泵的换热情况,室外工况温度越低,复合热泵的优势越明显。模拟名义工况下,名义工况下的换热量最高出现在水温30℃时,为71.66kw,相比空气源热泵高出18.21%,但太阳能热水温度30℃时蒸发器出风温度高于7℃,空气被额外加热,换热量也随风机风量的增大出现减小的趋势,表明30℃的水温度偏高。标准工况下,热水温度25℃时蒸发器出风温度均高于0℃,室外空调计算温度下,水温20℃时的蒸发器出风温度接近于-7.7℃。Nu随风机风量和室外温度的降低而增大,最终认为热水温度在20℃以下时较为合适。不同风机风量对翅片空气侧压力损失影响较大,压降随速度指数增大,根据空气源热泵与复合热泵空气侧压降及阻力特性,结合对应换热量、COP等认为风量15000m3/h时较为合适,折合风速2.07m/s。由不同工况时的蒸发器出风温度变化趋势得出,室外温度更低时,可适当调低太阳能热水的进水温度。
[Abstract]:Energy saving and emission reduction and efficient use of energy are highly concerned in the era of energy shortage. The energy consumption of air conditioning in building energy consumption accounts for a large proportion of the total energy consumption. Therefore, it is necessary to reduce the energy consumption of air conditioning by advanced technology improvement or system optimization. Air source heat pump (AHP) is a kind of high efficiency energy saving heat exchange equipment which takes air as the low quality heat source and absorbs the heat or cooling capacity in the air to achieve the purpose of heating or cooling. However, in the cold area of northern China, the use of air-source heat pump is restricted. When the outdoor temperature is low in winter, the evaporation temperature is lower and the exhaust temperature of compressor is too high because the evaporator is affected by low temperature. The heat pump can not operate normally due to the increase of compression ratio, but the heat load inside the building increases with the decrease of outdoor temperature, so that the heating energy consumption of air conditioning increases. Multi-energy comprehensive utilization is an effective way to solve the above problems, such as solar energy, biomass energy and other auxiliary heat transfer on the basis of air-source heat pump. In this paper, a new type of solar-air heat pump with two heat sources is used to optimize the structure of outdoor heat exchangers. The first row of heat exchanger tubes on the upwind side walk solar hot water to preheat the low temperature air entering the evaporator. Raise evaporator evaporation temperature. In this paper, a brand of 60kw-V air source heat pump is optimized. Firstly, the flow path of outdoor unit is optimized, and then the numerical model of outdoor heat exchanger without solar hot water is established. A layer of fin is selected as the calculation unit to simulate the effect on the heat transfer of air-source heat pump when the wind volume of each typhoon is increased from 9000m3/h to 18000m3/h with 3000m3/h as step under nominal operating conditions. The results show that the heat transfer increases with the increase of air volume and then tends to be stable. When the outdoor temperature is high, a single heat source air source heat pump can be used for heat supply. In addition, the larger the air volume, the greater the pressure loss on the air side. The numerical model of composite heat exchanger is established. The outdoor temperature is simulated under nominal (7 鈩，
本文编号：2383354
[Abstract]:Energy saving and emission reduction and efficient use of energy are highly concerned in the era of energy shortage. The energy consumption of air conditioning in building energy consumption accounts for a large proportion of the total energy consumption. Therefore, it is necessary to reduce the energy consumption of air conditioning by advanced technology improvement or system optimization. Air source heat pump (AHP) is a kind of high efficiency energy saving heat exchange equipment which takes air as the low quality heat source and absorbs the heat or cooling capacity in the air to achieve the purpose of heating or cooling. However, in the cold area of northern China, the use of air-source heat pump is restricted. When the outdoor temperature is low in winter, the evaporation temperature is lower and the exhaust temperature of compressor is too high because the evaporator is affected by low temperature. The heat pump can not operate normally due to the increase of compression ratio, but the heat load inside the building increases with the decrease of outdoor temperature, so that the heating energy consumption of air conditioning increases. Multi-energy comprehensive utilization is an effective way to solve the above problems, such as solar energy, biomass energy and other auxiliary heat transfer on the basis of air-source heat pump. In this paper, a new type of solar-air heat pump with two heat sources is used to optimize the structure of outdoor heat exchangers. The first row of heat exchanger tubes on the upwind side walk solar hot water to preheat the low temperature air entering the evaporator. Raise evaporator evaporation temperature. In this paper, a brand of 60kw-V air source heat pump is optimized. Firstly, the flow path of outdoor unit is optimized, and then the numerical model of outdoor heat exchanger without solar hot water is established. A layer of fin is selected as the calculation unit to simulate the effect on the heat transfer of air-source heat pump when the wind volume of each typhoon is increased from 9000m3/h to 18000m3/h with 3000m3/h as step under nominal operating conditions. The results show that the heat transfer increases with the increase of air volume and then tends to be stable. When the outdoor temperature is high, a single heat source air source heat pump can be used for heat supply. In addition, the larger the air volume, the greater the pressure loss on the air side. The numerical model of composite heat exchanger is established. The outdoor temperature is simulated under nominal (7 鈩，
本文编号：2383354
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