小型风冷热泵制冷剂充注量实验研究

以R22为工质,通过对风冷热泵冷热水机组制冷剂充注量实验测试研究,全面分析充注量对测试机组系统性能的影响及原因．针对充注量的影响作者提出了机组性能改进措施及方法,实现风冷热泵节能优化。     

YORK AWHC风冷热泵机组运行的两个问题

通过约克(YORK)风冷热泵机组实际运行中遇到的两个问题：制冷剂充注量及冷凝蒸发器冲垫故障，从理论上进行了分析，提出了解决方法。     

风冷热泵机组运行测试及分析

风冷热泵机组在我国被广泛用作空调系统的冷热源,尤其是在长江中下游地区.本文对在运行中风冷热泵机组进行测试,并对其性能进行了分析.要充分提高风冷热泵运行的效率,应注意空调系统与机组的匹配,注意机组自控设置等.     

改进风冷热泵冷热水机组除霜性能的实验研究

通过对一台风冷热泵冷热水机组除霜时使用热力膨胀阀和使用短管直接连通机组高低压侧的对比实验, 研究了不同节流装置对机组除霜性能的影响, 提出了改进风冷热泵冷热水机组除霜性能的一种方法。     

制冷剂充注量对冷藏车用制冷机组性能的影响

为了研究制冷剂充注量对冷藏车用制冷机组性能的影响,在数值模拟得到的制冷剂标准充注量的基础上,试验研究制冷剂充注量对压缩机吸/排气压力、吸/排气温度、蒸发器出口过热度、冷凝器出口过冷度及制冷能力的影响。研究表明,数值模拟方法得到的制冷剂标准充注量适用于实际制冷机组。     

R454B风冷涡旋式冷水(热泵)机组性能分析

对R410A和R454B在风冷涡旋式冷水(热泵)机组上进行性能对比测试，结果表明：在ASHARE额定工况下，R454B充注量约为R410A的83%;R454B制冷量较R410A低1.5%,制冷COP提高4.1%;R454B制热量较R410A低约1.6%～2.3%,制热COP高约3.1%～3.7%。另外，由于R454B排气温度较高，导致压缩机的运行范围略小于R410A。     

浅析水源热泵空调系统的调试

水源热泵空调系统的性能主要受水系统和制冷剂充注量的影响,通过调节循环水温度和流量以及制冷剂的压力可以使机组在最佳状态下运行,减少故障率,为设备生产企业节约售后服务费用。     

中小型风冷冷水机组的设计

所研究的机组主要应用于工业冷冻,也可作为中小型中央空调使用。详细介绍了风冷冷水机组各组成部分的选型计算,制冷剂的充注量相关内容。     

热泵机组制冷剂充注量补偿对化霜的改进

分析了热泵机组化霜效果差的主要原因是制冷剂充注量不足，计算了化霜时所需的充注量；提出使用制冷剂补偿器代替高压储液器，更能提高吸排气压力，缩短化霜时间，并通过试验证明效果明显。     

风冷热泵系统双流向膨胀阀应用研究

通过风冷热泵冷热水机组实验测试，研究双流膨胀阀在风冷热泵制冷系统中的应用，探索简化制冷系统，提高制冷系统运行可靠性与提高系统性能以及减少制冷系统耗材，降低机组成本的方法。     

家用热泵空调的系统模拟和实验研究

本文通过对家用热泵型空调的运行分析,针对热泵型空调自身特点,主要考虑制冷剂充灌量和蒸发器结霜对系统性能的影响,并建立系统模型。进行了模拟计算,并对蒸发器结霜做了动态计算,分析了蒸发器结霜和制冷制充灌量对系统性能的影响。计算结果与实验结果较吻合。     

外绕微通道冷凝器空气源热泵热水器仿真与优化

空气源热泵热水器比燃气或电热水器更为节能。本文提出了一种外绕微通道冷凝器,可以减少制冷剂充灌量、提高换热效率、降低成本、提高安全性。建立了热泵热水器的准稳态系统模型,制冷剂侧采用稳态模型,水箱和水侧采用动态模型。通过实验证明了该系统模型可以准确地预测时变的系统功耗、水温,以及系统时均COP。通过仿真分析,发现水箱隔热层可以缩短水的加热时间、并提高系统COP约9.2%。增大冷凝器也可提升系统COP,但几乎不改变水的加热时间。最后提出了微通道冷凝器的三流程优化设计方法。     

微通道换热器在热泵型空调机组中的应用

将微通道换热器应用到北美市场典型的分体式热泵型空调机组中,并对采用微通道换热器的机组和采用铜管翅片式换热器的原机组的性能进行试验对比。试验结果表明,室内室外机均采用微通道换热器后,机组能力提高4％,制冷季节能效比（SEER）与制热季节能效系数（HSPF）分别提高2％和1％,换热器质量减轻44％,制冷剂充注量减少51％。平均结霜时间与原机组相比延长5％,平均除霜时间比原机组延长4％。此外,通过优化设计,制冷剂的分布更加均匀。对室外机微通道用换热器进行耐腐蚀性测试和压力交变疲劳测试,结果表明微通道换热器具有良好的可靠性。     

Modeling evaluation of a direct-expansion solar-assisted heat pump water heater using R410A

A direct-expansion solar-assisted heat pump (DX-SAHP) system by using R410A as refrigerant is described, which can supply domestic hot water during the whole year. Based on the distributed parameter and homogeneous flow models of collector/evaporator and condenser, the lumped parameter models of compressor and electronic expansion valve, and the refrigerant charge model, a numerical model is developed to estimate the thermal performance of the system. Given the structure parameters, meteorological parameters, initial and final water temperatures, for a fixed superheat degree, the effects of the refrigerant charge quantity on the performance parameters of the system are analyzed, such as compressor power, heat gain of collector, heating time, collector efficiency and system COP. Furthermore, for a fixed refrigerant charge quantity, the effects of various parameters, including solar radiation, ambient temperature, compressor speed and initial water temperature, have been simulated and analyzed on the thermal performance of the system.     

带有高压贮液器的热泵系统不同充灌量下的实验研究

高压贮液器是制冷、空调、热泵系统中的常用部件，但其对系统性能的影响在相关系统性能分析时却常被忽视。通过实验讨论了在充灌量过少、适量、过量的情况下，高压贮液器对系统工况和性能的影响与制约，并给出了充灌量过少、适量、过量的简易判别标准。     

Propane heat pump with low refrigerant charge: design and laboratory tests

Independently of the choice of refrigerant, environmental and or safety issues can be minimised by reducing the amount of refrigerant charge per heat pump or refrigeration system. In the investigation reported here, a laboratory test rig was built, simulating a water-to-water heat pump with a heating capacity of 5 kW. The system was designed to minimize the charge of refrigerant mainly by use of mini-channel aluminium heat exchangers. It was shown that the system could be run with 200 g of propane at typical Swedish operating conditions without reduction of the COP compared to a traditional design. Additional charge reduction is possible by selecting proper compressor lubrication oils or by using a compressor with less lubrication oil.     

Performance of an air to air heat pump in a temperate climate

The performance of a commercial air-air heat pump installed in an occupied house in New Zealand is reported. The data cover operation both before and after the heat pump was extensively modified to improve the efficiency and reliability. The consequences of the non-optimal refrigerant charge and capillary in the original unit are illustrated and the advantages of installing a suction accumulator, crank-case heater and other improvements described. The results also show the sensitivity of the operating time to changes in the heating capacity and the difficulty in sizing a heat pump for normal residential use.     

Effects of refrigerant charge amount on the performance of a transcritical CO2 heat pump

A typical transcritical CO₂ system shows lower performance than conventional air conditioners in cooling mode operation. In addition, the CO₂ system shows a large variation of the performance according to refrigerant charge whereas the conventional systems do not show large variation. In this study, the performance of the CO₂ heat pump was measured and analyzed by varying the refrigerant charge amount at standard cooling condition. In addition, the performance sensitivity of the CO₂ system as a function of refrigerant charge was compared to those for the R22, R410A, and R407C systems. The cooling COP of the CO₂ system was reduced more significantly at undercharged conditions than at overcharged conditions as the deviation from the optimal charge increased. The expansion loss was the dominant factor affecting system performance at undercharged conditions, while the gascooler loss became the major parameter at overcharged conditions. Among the systems investigated and compared in this study, the CO₂ system showed the most reduction in performance at undercharged conditions.     

Performance comparison between a single-stage and a cascade multi-functional heat pump for both air heating and hot water supply

Multi heat pumps have been widely used in buildings due to their higher energy efficiency. Recently, demands for multi-functional heat pumps, which can provide heating, cooling, and water heating in a building, have been increased. In this study, a cascade multi-functional heat pump, combining a multi heat pump using R410A for air heating with a water heating unit using R134a for hot water supply, was investigated experimentally. The performance of the cascade multi-functional heat pump was measured by varying the refrigerant charge amount, EEV opening, water flow rate, and water inlet temperature. Test results were compared with those of a single-stage multi-functional heat pump using R410A for air and water heating. The cascade multi-functional heat pump adopting the water heating unit showed more stable air and water heating operations and higher water outlet temperatures than the single-stage multi-functional heat pump.     

非共沸混合工质自复叠热泵相积存实验研究

混合工质循环浓度是影响自复叠热泵循环性能的主要因素之一,而相积存导致工质循环浓度偏离充灌浓度,造成热泵性能变化.实验结果表明热泵中存在明显的相积存,最大可达充灌总量的50%以上;加热水温度对相积存的影响很大,每升高10℃,积存量减少10%～21%;工质充灌浓度一定时,积存量随充灌量的增大而增加,工质充灌量增加10%,其积存比例增加1%左右.相积存导致工质循环浓度高于充灌浓度1.6%～37%,由于工质积存量随加热水温度的升高不断降低,循环工质浓度受相积存的影响也不断减小而逐渐接近充灌浓度.