温湿度独立控制空调系统的应用

温湿度独立控制系统具有避免常规空调系统中冷源能源品位的损失、满足不同热湿比变化的要求及处理设备均为干工况运行等优点。干式风机盘管加新风空调系统虽值得推广,但在运行中存在一些问题。叙述了温湿度独立控制空调系统的特点及应用,指出,利用全热交换器预处理新风是解决干式风机盘管空调系统运行困难和降低新风机组能耗的有效手段。     

石墨烯铝箔复合材在板翅式热交换器中应用研究

板翅式热交换器是减少新风负荷的主要热回收装置,其芯体主要材料是铝箔,但铝箔存在着热回收效率较低的问题。石墨烯具有很好的热学性,对铝材表面修饰能提高其传热系数,导热性能远远优于其他填料。石墨烯铝箔复合材料替代铝箔作为板翅式热交换器芯体,能使板翅式热交换器的显热换热效率提高10%～14%。     

芯体机能材料对静止式全热交换器性能的影响

静止式全热交换器的关键构件是换热芯体,换热芯体中的机能材料要求其具有良好的传热、透湿性能,一般采用经过特殊处理的纸材或膜结构,这些材料的性能又是全热交换器实现热湿交换的关键。从理论上分析了机能材料交换膜厚度和质扩散系数对静止式全热交换器性能的影响,对国内外开发的15种芯体机能材料进行了性能试验,并对其中的6种材料制成的芯体所具有的热湿交换性能和有效换气率进行了测试对比。结果表明,交换膜的厚度和材料的透湿性对芯体潜热效率的影响显著,而材料的透气度将直接影响到芯体的有效换气率。     

保证室内空气品质的置换通风的节能研究

介绍了置换通风的原理及其能够改善室内空气品质的原因,运用送风量及送风温度的公式,对置换通风及混合通风进行了计算比较。通过具体工程实例的计算表明:置换通风其送风量比混合通风的送风量减少16.7%,节约能耗41%,新风节能2.46W,是一种能改善室内空气品质的节能方法。     

空调新风问题的探讨

本文对新风量的大小与空气品质的关系,新风送风方式与空气品质的关系进行了探讨,指出一味增大新风量并不能达到显著改善室内空气品质的效果,应结合新风的送风方式,并指出置换通风是一种较好的新风送风方式。     

空气源热泵新风机组节能防冻研究

本文讨论了寒冷地区新风机组冬季被冻坏的原因及传统解决方法的问题,提出了空气热泵新风机组节能防冻新方法,即利用热泵冷凝器回收排风废热以加热引入室内新风。新系统的运行经验表明,各种温度随时间的变化趋于稳定,热泵的平均COP=3．7—4．6,节约电能达52％～84％,解决了防冻问题并改善了室内空气质量。     

空调列车增加新风量全热交换器的运行性能研究

通过仿真计算的方法,分析比较了列车空调机组增加新风量时全热交换器的运行性能。结果表明：直接增加新风量不可行,应用全热交换器后空调机组的出风温度满足要求,并且节能效果明显。     

以PM2.5设计浓度计算净化风量的方法研究

净化风量是新风系统设计的重要指标,本文对现阶段常用的净化风量计算方法进行综述,通过小学教室新风系统具体案例比较了各种计算方法,并根据JGJ/T461-2019《公共建筑室内空气质量控制设计标准》,提出了以PM_(2.5)设计浓度计算净化风量的具体方法,为教室内净化风量的合理确定提供计算依据。     

上海期货大厦变风量空调系统实际运行状况的初步分析

对上海期货大厦内变风量空调系统的实际运行状况,如室内空气品质,新风供给,吊顶回风、能耗等方面问题进行了初步分析。以期对今后VAV空调系统的应用有所借鉴。     

浅析空调全热式交换器新风系统的经济性

详细比较了全热式交换器新风系统与传统外接冷热源新风系统在初投资与运行费用上的区别。     

Investigation of prototype thermoelectric domestic-ventilator

Applications of thermoelectrics had been enlarged from conventional single refrigeration or generation to waste heat recovery with tough energy consumption of the world. With improvement of living standard more and more domestic air-conditioners are used in Chinese families now. Percentage of power consumption of domestic air-conditioner caused by heat load of fresh air supply increased after SARS, which could be prevented efficiently with sufficient fresh air supply, broke out in China in 2003. A novel prototype thermoelectric domestic-ventilator with heat recovery of exhaust of air-conditioned room had been made in Hunan University thermoelectric lab. A thermoelectric heat exchanger and a flat-fin cross flow heat exchanger were integrated in this ventilator. This ventilator was investigated and its cooling (and heating) performance were evaluated in terms of the coefficient of performance, cooling and heating powers, and being handled temperature difference of fresh air. The coefficient of performance of this ventilator was found to be over 2.5 in the whole experiment. The optimal working parameters of this ventilator were studied in this paper. The potential improvements in performances and market prospects were also discussed in this work.     

Research on a Refrigeration Dehumidification System with Membrane-Based Total Heat Recovery

An independent air dehumidification system is helpful to improve indoor air quality and decrease energy consumption by heating, ventilation, and air conditioning (HVAC). A refrigeration dehumidification system with membrane-based total heat recovery is the key equipment to realize this goal. The system comprises two subsystems: a membrane total heat recovery and a direct expansion refrigeration system. The total heat exchanger has a membrane core where the incoming fresh air exchanges moisture and temperature simultaneously with the exhaust air. In this manner, the total heat or enthalpy from the exhaust air is recovered. Then the fresh air flows through a cooling coil where it is dehumidified below the dewpoint. Finally, the cold and dry air is supplied to indoors. A prototype of practical application is designed and fabricated. Experiments are conducted under variable operating conditions in the psychrometric calorimeter chamber. The effects of varying operating conditions like temperature and air humidity on the air dehumidification rate, cooling power, coefficient of performance, and compressor power are evaluated with indoor exhaust air dry bulb 27°C, wet bulb 19°C, and fresh air flow rate 200 m³/h. In comparison with a conventional refrigeration dehumidification system, the coefficient of performance and air dehumidification rate of the prototype are 2.3 times and 3 times higher, respectively. The performance of the prototype is rather robust under a hot and humid environment.     

湿式空气热量回收过程的场协同分析

在介绍湿式空气热量回收装置和场协同含义的基础上,对湿式空气热量回收过程中影响换热性能的各个因素进行了场协同分析。结果表明,在湿式空气热量回收装置中,排风及新风的风速以及换热芯体的板间距、板宽、板高等因素都会对换热效果产生不同程度的影响。研究结果对于湿式空气热量回收装置的优化设计具有一定的参考价值。     

Performance simulation of a low‐swirl burner for a Stirling engine

A new type of gas burner for Stirling engine that can recover adequate heat from exhaust gas was designed based on the plate heat exchanger and low‐swirl combustion technology, which consists of three components: a cyclone, a burner, and a circular plate heat exchanger. The circular plate heat exchanger tightly wound around the combustion chamber plays a high efficiency of heat recovery role. In consideration of the radial symmetry of the burner, a three‐dimensional numerical simulation was carried out by Ansys15. The velocity distribution, temperature distribution, and pressure distribution of the combustion gas were presented respectively. Strong backflow that came from the exhaust gas around the root of the flame in the combustion chamber and a vortex below the inlet of the exhaust gas channel were found, which were beneficial for the combustion and improving the uniformity of temperature distribution. Combustion behaviors of the burner under standard operating conditions were obtained, the highest temperature was about 2200 K in burner and the exhaust gas entered the plate heat exchanger at the temperature of 1375 K and exited at 464 K, with the waste heat recovery efficiency over 65.8%. And, the air‐fuel ratio and combustion power had negligible effect on the waste heat recovery efficiency.     

Heat pipe heat exchanger for heat recovery in air conditioning

The heat pipe heat exchangers are used in heat recovery applications to cool the incoming fresh air in air conditioning applications. Two streams of fresh and return air have been connected with heat pipe heat exchanger to investigate the thermal performance and effectiveness of heat recovery system. Ratios of mass flow rate between return and fresh air of 1, 1.5 and 2.3 have been adapted to validate the heat transfer and the temperature change of fresh air. Fresh air inlet temperature of 32–40 °C has been controlled, while the inlet return air temperature is kept constant at about 26 °C. The results showed that the temperature changes of fresh and return air are increased with the increase of inlet temperature of fresh air. The effectiveness and heat transfer for both evaporator and condenser sections are also increased to about 48%, when the inlet fresh air temperature is increased to 40 °C. The effect of mass flow rate ratio on effectiveness is positive for evaporator side and negative for condenser side. The enthalpy ratio between the heat recovery and conventional air mixing is increased to about 85% with increasing fresh air inlet temperature. The optimum effectiveness of heat pipe heat exchanger is estimated and compared with the present experimental data. The results showed that the effectiveness is close to the optimum effectiveness at fresh air inlet temperature near the fluid operating temperature of heat pipes.     

温室空气-土壤换热系统的数值模拟

该文用FLUENT5.4软件对空气－土壤换热器（SHESS）进行三维动态模拟计算。研究了换热器进出口温度随时间的变化、温度和压力在换热器中的分布。,要用双排管布置，可以保证所有管内的流量均匀分布；采用压头150Pa的排风扇可以保证管内空气流速在最佳范围之内。空气－土壤换热器在华南地区冬季气温回暖期间对温室有明显的降温效果。     

Compact potential of exhaust heat exchangers for engine waste heat recovery using metal foams

To improve the practicability of the waste heat recovery system for internal combustion engines, the compact potential of exhaust heat exchangers using metal foams is investigated. In the present study, the performance of compact exhaust heat exchangers is compared with that of a conventional shell and tube heat exchanger in a real test bench. Both heat transfer and pressure drop performance are considered when assessing the performance of heat exchangers because these two factors normally show a trade‐off relationship when designing exhaust heat exchangers. Compared with the conventional heat exchanger, the compact heat exchanger can achieve a similar pressure drop, and at the same time the heat transfer is increased by 30%, whereas the volume and the weight are each reduced by 2/3. The performance of compact heat exchangers with six types of Ni metal foams is also investigated under different mass flow rates and thicknesses of the porous layer. Results show that the optimum compact heat exchanger enhances the comprehensive performance 1.9 times compared with original one. This study shows that metal foams have great potential in realizing a compact exhaust heat exchanger for engine waste heat recovery.     

脉动热管用于空调排风余冷回收的试验研究

设计加工1台脉动热管式换热器,用于夏季工况空调排风的余冷回收。通过实验,分析了风速、新排风温差等因素对余冷回收效率的影响,以及两侧压力损失随风速的变化情况。结果表明,余冷回收效率随新风、排风温差增大而升高,随风速的增大而降低。该换热器具有一定的优势,但还需进一步改进结构,以提高其效率。     

地铁站台系统的热环境及废热回收

本文对哈尔滨地铁站台环境温度变化、热负荷产生的原因进行了分析预测,分析得出列车运行和新风负荷所占比例最大。选择地铁站台空气调节计算参数后,计算了地铁站台的逐时热负荷,定量描述吸气、排气和站台壁面温度变化,其结果显示：站台排气温度和站台壁面温度逐年上升。地铁可回收废热量的计算结果可为废热回收系统提供依据。     

Improving heat recovery using retrofitted heat pump in air handling unit with energy wheel

The world is facing a challenge to reduce energy use to meet the environmental goals set for the future. One factor that has a great impact on the energy performance of buildings is the ventilation losses. To handle these losses, heat recovery systems with rotating heat exchanger are often implemented. These systems have been shown to recover about 60–70% of the energy in the exhaust air on an annual basis.After a heat recovery system is installed it is hard to improve the efficiency of the installed recovery system with an acceptable economic payback period. In the present paper one way to improve the energy performance of a building with this type of heat recovery system by the use of a heat pump is investigated by simulations in TrnSys.The heat pump system is arranged so that the evaporator is connected to a heat exchanger mounted in the exhaust airstream after the energy wheel, and the condenser of the heat pump is mounted so that the temperature of return water from the heating coil is increased.The simulations show that there is a possibility to increase the heat recovery rate of the air handling unit in a significant way by retrofitting a heat pump to the system.