转轮除湿复合式空调系统的探讨

转轮除湿复合式空调系统利用转轮除湿处理新风用于承担室内湿负荷,室内显热冷负荷和新风显热冷负荷由干冷设备承担,可有效地控制室内温度和湿度.复合式空调系统采用热回收装置可有效地节约新风冷负荷和提高除湿能力,当新风送风温度等于室内设计温度时,系统冷水采用高温冷水(18/21℃),可有效地提高制冷机组性能系数,节约制冷能耗42.83%.但转轮除湿再生能耗过高,复合式空调系统总能耗远大于传统空调系统,降低转轮除湿再生能耗是复合式空调系统应用的关键问题.     

氯化锂吸附除湿空调系统的实验研究

本文对以氯化锂为吸湿剂的吸附除湿空调系统进行了实验研究,实验结果表明该空调系统再生空气的最佳温度为90℃;空调工况下制冷系数COP在41～51%之间;如果再生空气温度低于80℃,则COP低于20%.并且还讨论了该空调系统各个操作参数之间的相互关系.本文取得的实验数据为吸附除湿空调系统的进一步完善提供了可靠依据.     

硅胶转轮除湿机的试制

应国内某些行业需要生产环境空气温度18～25℃、相对湿度2～5%、空气露点温度低于-40℃的低露点环境除湿设备的要求,锡山市西漳除湿设备厂在生产能处理低温低湿空气的氯化锂转轮除湿机的经验基础上,通过对硅胶吸湿剂物理性能和吸湿原理的理解,试制成硅胶吸湿纸,并对硅胶吸湿纸进行了动态和静态的小样试验,再对硅胶转轮除湿机的转芯结构尺寸、转速、除湿量、运行参数进行确定.对转芯增设了冷却区.硅胶转轮以设定的转速连续旋转,除湿,再生,冷却三区工作同时进行.采用冷冻除湿和硅胶吸附干燥除湿相结合的系统,将空气处理到含湿量＜0.4g/kg(( ))的需要值,空气露点温度达到-46℃.填补了我国不能生产低露点环境除湿设备的空白.     

转轮除湿空调系统及吸附剂再生特性研究进展

转轮除湿空调系统可实现温湿独立控制,与传统空调相比具有舒适、节能、环保等优点。本文阐述了转轮除湿空调系统及其吸附剂再生特性的研究进展,包括转轮除湿空调系统形式及其特性、转轮除湿性能和吸附剂再生方式及再生特性等内容。最后,指出了目前转轮除湿空调系统的研究不足,并对转轮除湿空调系统进一步研究方向提出了建议。     

温湿度独立控制系统特殊设备专利介绍

空调系统的任务是将室内的余热、余湿排出室外,并提供满足卫生要求的新风。目前,大型建筑空调系统通常采用冷却方法进行除湿,冷冻水的温度需要同时满足供冷与除湿的要求。如单独满足供冷需要,冷冻水温度只需16-18℃即可,而如需同时满足冷却及除湿则需要冷冻水温度5-7℃。这样本来可以采用高温冷源（16-18℃）带走的热量由于与除湿一起共用5-7℃的低温冷源进行处理,造成能量利用品位上的浪费。一些情况下,除湿后还需要对空气进行再热处理,更是加大了冷源浪费。     

一个可利用低品位热能的双级除湿冷却式空调系统

本文建立了一个可利用低品位热能的双级除湿冷却式空调系统及其数学模型，并用该模型模拟香港一办公楼作为新风系统的除湿冷却式空调系统。计算机模拟结果显示：双级系统所需的再生温度仅为５９．０℃，较单级系统低２４．２℃，这使得低品位热能的利用成为可能；双级除湿冷却式空调系统可提供湿度足够低的送风，以承担全部湿负荷，故该系统可以很好地与冷幅射天花板系统配合使用，从而实现显热与潜热的分别处理，提高温湿度的控制精度；而且由于机械制冷仅仅被用于消除显热，所以可以提高制冷系统的蒸发温度从而提高制冷系统的性能系数。     

液体除湿空调再生传质特性的实验研究

分析了液体除湿空调再生过程热质交换的耦合特性,并提出了提高再生过程热质交换性能的措施,在此基础建立了液体除湿空调系统,其中再生器采用逆流式填料塔,在填料塔设置中间加热器,利用排风进行再生。使用氯化锂作为除湿剂,实验分析了影响再生传质性能的主要因素以及提高再生性能措施的有效性,结果表明：再生溶液温度、流量以及空气流量对再生传质量的影响比较显著,为了保证一定的再生量,溶液温度一般不低于60℃;采用室内排风再生和再热器再热均增强了再生过程传质势,提高了再生量。     

具有调温除湿功能空调系统的实验研究

为综合考虑温度和湿度的需求,本文提出一种具有升温和调温除湿功能的房间空调系统,并根据本机组在空调和除湿模式下的系统运行性能,找到最佳的除湿模式和压缩机控制方案。结果表明,该机组可实现空调模式、升温除湿模式和调温除湿模式;调温除湿模式比升温除湿模式的出风温度低约7%,出风相对湿度低约27%;前者的除湿量约为后者的2.8倍,单位功率除湿量约为后者的2.6倍;当室外温度<18℃时,启用升温除湿模式,压缩机可采取变频调节方式;当18 ℃≤室外温度≤24 ℃时,启用调温除湿模式,压缩机可采用“容量调节+变频”方式。该系统可有效解决长江中下游地区的房间空调器除湿后送冷风的问题。     

浅谈术语“气体吸湿剂＂

“固体吸湿剂”、“液体吸湿剂”常作为吸湿剂中的两大类型被提及。固体吸湿剂利用吸附原理,对湿空气进行除湿;液体吸湿剂利用吸收原理,使空气达到除湿的效果。而压缩空气作为一种极为干燥的空气,我们称之为“气体吸湿剂”,此空气通过和湿空气混合,实现对湿空气稀释除湿的目的。同时经过压缩空气气体吸湿剂除湿后的空气可以与蒸发冷却技术相结合应用于空调中,大大提高蒸发冷却降温的效率。另外,在我国西北等干燥地区大气中存在着一种经过大自然除湿后的天然干燥空气一千空气,我们可充分利用这种气体吸湿剂,直接送入建筑物内消除室内的湿负荷,大大降低人工制冷除湿的能耗,同时充分利用“干空气能”,达到尽量采用蒸发冷却天然冷源降温的效果,从而实现建筑低能耗的目的。“气体吸湿剂”是一种新的吸湿剂概念,为此,本文对术语“气体吸湿剂”进行了初步的探讨。     

利用室内空气循环净化降低实验动物房新风量的节能效果

为保证实验动物房的室内污染物浓度处于较低水平,传统空调系统一般采用大风量的全新风系统,空调能耗巨大。针对控制污染物浓度所需新风量远高于控制其他参数所需新风量的情况,本文提出了可实现温度、湿度、污染物独立控制的新型空调系统,以达到降低新风量、减少空调能耗的目的。以笼盒式实验动物房为例,利用CFD软件模拟了该系统的净化效果并研究节能性,结果表明：当设置新风换气次数为8.53 h-1、循环换气次数为13 h-1、循环送风温度为19.4 ℃时,可满足室内温度、湿度、污染物浓度要求,保证小鼠正常生存;相比传统全新风系统,循环净化系统的新风量减少了57.4%,能耗降低了47.9%。     

Exergoeconomic performances of the desiccant-evaporative air-conditioning system at different regeneration and reference temperatures

This paper presented the exergoeconomic evaluation of the developed desiccant-evaporative air-conditioning system. The developed system was evaluated based on the steady-state conditions at different regeneration and reference temperatures. The exergoeconomic evaluation method was implemented to the system components and the whole system to evaluate the exergy efficiency, exergy destruction ratios, cost rates, relative cost differences and exergoeconomic factors. The regeneration and reference temperatures affected the exergy efficiencies, exergy destruction ratios, cost rates, relative cost differences and exergoeconomic factors. The desiccant wheel, heating coil and evaporative cooler had a high cost rate (investment cost, operation and maintenance cost, and exergy destruction cost). The exit air fan, outdoor air fan and evaporative cooler had a high relative cost difference. The exit air fan, outdoor air fan and secondary heat exchanger had a high exergoeconomic factor. Replacement of the desiccant wheel with a higher dehumidification performance could decrease the high cost rate. A higher efficiency evaporative cooler and heating coil were needed. Cheaper air fans (outdoor air fans and exit air fans) were needed.     

Effect of desiccant isotherm on the performance of desiccant wheel

Numerical simulation has been conducted for the desiccant wheel, which is the crucial component of a desiccant cooling system. As the key operating/design parameters, the rotation speed and the area ratio of regeneration to dehumidification have been examined for a range of regeneration temperature from 50 °C to 150 °C. Optimization of these parameters is conducted based on the wheel performance evaluated by means of Moisture Removal Capacity (MRC). Simulations are focused on the effect of desiccant isotherm on the optimal conditions of these operating/design parameters. Also the effects of the outdoor air temperature and humidity on the optimum design parameters are examined.     

Characterization of desiccant wheels with alternative materials at low regeneration temperatures

A number of new desiccant materials have been proposed which have the potential to improve the performance of desiccant wheels being regenerated at low temperature. Desiccant wheels containing two such desiccant materials (zeolite and superadsorbent polymer) were compared with a conventional silica gel desiccant wheel. The superadsorbent polymer desiccant wheel achieved greater dehumidification than the silica gel wheel when dehumidifying high relative humidity air with low temperature (50 °C) regeneration air. The temperature of dehumidified air exiting the polymer wheel was also lower. The zeolite desiccant wheel was generally less effective at dehumidifying air and had a higher pressure drop.     

Use of compound desiccant to develop high performance desiccant cooling system

The paper is aimed to develop a high performance rotary solid desiccant cooling system using a novel compound desiccant wheel (DW). The unique feature of the desiccant wheel is that it can work well under a lower regeneration temperature and have a higher dehumidification capacity due to the contribution of the new compound desiccant materials. Experimental results indicate that the novel desiccant wheel under practical operation can remove more moisture from the process air by about 20–40% over the desiccant wheel employing regular silica gel. A mathematical model that is used to predict the system performance has been validated with the test results. By integrating the desiccant wheel with evaporative cooling, heat recovery and heating for regeneration sections, a solid desiccant cooling system can be formed. Simulation results show that because of the use of the new compound desiccant, the desiccant cooling system can work under much lower regeneration temperature and have a relative high COP, thus low grade thermal energy resources, such as solar energy, waste heat, etc., can be efficiently utilized to drive such a cooling cycle.     

A hybrid solar air conditioner: Experimental investigation

The removal of moisture from the supply air using conventional air conditioners (A/C) represents a considerable portion of the air conditioning load in hot and humid regions. Desiccant assisted A/Cs are used to address this issue. In this work, the performance of a hybrid A/C, which consists of a desiccant wheel, an enthalpy wheel, and a vapor compression cycle (VCC), is investigated experimentally. The effect of the process air stream's temperature and humidity, and the effect of the ventilation rate on the hybrid A/C performance are investigated. The experimental results show that the hybrid A/C is more effective than the standalone VCC in maintaining the indoor conditions within the comfort zone. The simulation of the complete hybrid solar A/C that uses a concentrating photovoltaic/thermal collector shows that a system coefficient of performance higher than unity is possible.     

热泵型溶液除湿新风系统性能分析与优化

本文建立了热泵型溶液除湿(HPLD)新风系统数学模型,研究了新风温度、湿度对系统运行性能的影响。结果表明:新风温度升高1℃,系统COP平均下降率为0.9%;新风含湿量增加1 g/(kg干空气),系统COP平均下降率为3.6%,新风湿度增加导致HPLD系统COP大幅下降,系统新风湿度变化的适应性差。为扩大HPLD系统适应范围,提出了冷却除湿与HPLD组合式除湿系统,以组合式除湿系统COP为评价指标,得到组合系统级间新风参数最优状态:温度为21℃,含湿量为14.1 g/(kg干空气)。夏季典型工况下,组合式除湿系统COP为5.40,比单一HPLD系统COP提高87.5%。最后,根据HPLD系统设计参数制作了实验样机,并对模拟结果进行了验证。     

Effect of regeneration temperatures in the exergetic performances of the developed desiccant-evaporative air-conditioning system

The developed desiccant-evaporative air-conditioning system was evaluated using the exergetic method under controlled environmental conditions to determine the performances of the whole system and its components.Percentage contributions of exergy destruction of system components at different regeneration temperatures and reference temperatures were determined. Exergy destruction coefficient of different components at different regeneration and reference temperatures were presented. It was shown that exergetic performances varied with respect to the regeneration and reference temperatures. The exergetic performances based on thermal, electric, total exergy input, first definition and second definition efficiencies were shown.Based on the results, reference and regeneration temperatures affected the determination of the system performances and its components. It was shown that air-heating coil, air fans and desiccant wheel contributed to large percentage of exergy destruction. Hence, the mentioned components should be given attention for further improvement of the system performances.     

体育馆蒸发冷却空调系统的探讨

常见的体育馆蒸发冷却空调系统存在设备占用空间大、安装困难、室内温、湿度大的问题,本文提出用太阳能驱动除湿转轮加间接蒸发冷却(IEC),再加直接蒸发冷却(DEC)的空调系统来解决常用蒸发冷却空调系统送风温湿度高的问题;利用体育馆的排风作为辅助房间用商用中央空调的冷源,一方面解决体育馆大空间蒸发冷却系统的排风问题,提高室内的舒适度,另一方面,体育馆辅助房间空调的安装和控制问题得到很好解决,节能效果明显.     

Performance analysis of air cycle refrigerator integrated desiccant system for cooling and dehumidifying warehouse

In this paper, the performance of air cycle refrigerator integrated desiccant system used to cool and dehumidify warehouse is analyzed theoretically. Simulation analysis is carried out to calculate the system coefficient of performance, cooling effects and the humidity change under different values of pressure ratio, storage zone temperature inside dock and outdoor air conditions. Also, the effect of the air cycle and the rotor parameters on the system performance is evaluated. From the simulation result it is found that, the desiccant system has the ability to supply air to the dock area at very low humidity. The system coefficient of performance increases due to the exhaust heat recovery on the desiccant system, and this enhancement can be more than 100%. The coefficient of performance of the proposed system is greater than that of a conventional system under the same operating conditions.