水循环式热泵干燥装置的分析

热泵干燥装置具有节约能源、环境友好、可低温干燥等特点。水循环式热泵干燥装置是指热泵和干燥部分通过水循环耦合而成的热泵干燥装置,与热泵和干燥部分直接耦合相比,具有不向环境排放热量、机组调控性好、对干燥过程的匹配性好、成本低等优势,是一种较适宜于中小型热泵干燥装置的结构型式。     

余热回收式热泵干燥装置的设计与分析

为提高热泵干燥装置的节能效率,设计并研制了能够对干燥室排出的高温气体进行余热回收的热泵干燥装置,并对其进行了性能测试。采用可编程控制器对热风的温度、湿度和风速进行调节,并可对干燥室排出的废热进行回收利用。利用该热泵干燥装置对香菇进行的干燥实验表明:该热泵出风口温度可达65℃,干燥室内温度分布均匀;与电加热干燥装置相比,该装置的干燥时间可缩短5~7 h,每度电的处理量提高了2.3倍,并且提高了干燥品质。     

高温热泵在木材加工行业中的应用

分析了国内外木材加工行业中高温热泵的研究与应用现状,提出了采用高温热泵回收单板干燥尾气的方案,认为当前要重视高温热泵工质及相应热泵系统的研制,发展高温热泵与太阳能和常规蒸汽干燥的联合干燥技术,使高温热泵干燥装置标准化和规范化,保证机械的产品质量与稳定性,扩大高温热泵干燥机在我国的使用范围。     

热泵干燥技术的发展及其应用的前景

1　引言热泵技术是世界上70年代末80年代初发展起来的一项高新技术。作为工业热泵技术在我国的发展也有十多年的历史了。而热泵干燥技术是以它独特的干燥原理及其高效能被人们所重视。特别是在家具、木材加工行业中的应用,优点十分显著,因此,我国早在80年代中期木材加工业就引进了德国、意大利、荷兰等热泵木材干燥装置。热泵干燥装置的市场占有比例在逐年提高,在木材干燥领域中已占到第二位。热泵技术在其它工业领域应用,随着国民经济的经济发展,也会越来越受到大家的欢迎。2　热泵干燥技术的特点热泵技术应用于干燥领域有着十分明显的优势…     

热泵干燥装置的节能研究

对热泵干燥装置混合工质进行优选,建立典型热泵干燥装置结构数学模型,研究提出目标函数并开发出适合热泵干燥结构的程序算法。     

热泵干燥系统优化的理论分析

用当量温度法对热泵干燥的最佳工况进行了详细的分析计算,提出热泵干燥装置最佳蒸发温度概念,它对热泵干燥装置的节能运行具有指导意义,比较了不同制冷工质的干燥效果,研究了回热循环的节能原理。     

热泵粮食种子干燥装置研制

谷物种子的干燥处理一种是自然通风干燥．摊晒法：另一件是人工烘干处理．即热风干燥法。这里介绍一种与常现热风干燥不同的热泵除湿干燥法．它的优点主要是保证谷种的干燥质量和节约能源。本文取材于1994年1月热泵粮食种子干燥装置研制的鉴定文件．它总结了该装置研制、设计的过程和主要技术参数。     

红枣超声波-热泵协同干燥动力学试验研究

为了进一步研究超声波对红枣热泵干燥过程的作用规律,本文以闭式热泵干燥系统为基础增加超声波装置建立超声波-热泵联合干燥系统,在不同温度、超声波频率、功率条件下对新鲜红枣进行超声波-热泵联合干燥试验研究。结果表明,超声波-热泵联合干燥可以加快红枣干燥速率,超声波功率的增大和频率的升高对红枣的干燥具有显著的促进效果。     

太阳能-空气源热泵联合干燥系统设计及干燥枸杞的实验研究

为缩短枸杞干燥时间,提高干制枸杞的质量,减少能源消耗,本文提出了一种新型太阳能–空气源热泵联合干燥系统。该系统主要由太阳能集热器和空气源热泵机组等设备组成,可以实现太阳能单独干燥、热泵单独干燥和太阳能–空气源热泵联合干燥三种工作模式。本文根据枸杞的干燥特性,分段设定最佳的干燥温度,进行了热泵单独运行和太阳能–热泵联合运行两种工作模式下干燥枸杞的对比实验。结果表明,干燥50 kg枸杞,太阳能–热泵联合运行比热泵单独运行节省了2.9 kW?h电能,若同时除去系统本身的耗能,节省的电能占热泵单独运行耗电量的29.5%。同时,与太阳能单独干燥相比,太阳能–热泵联合干燥具有较高的除湿能耗比,两者最大差值为0.71 kg/(kW?h)。本文提出的太阳能–热泵联合干燥系统具有提高干燥产品的品质、缩短干燥时间和节约干燥成本等优点,适宜推广。     

空气回热闭式热泵干燥系统实验研究

空气闭式热泵干燥装置和加装空气回热器的空气闭式热泵干燥装置的对比试验表明，后者比前者除湿能耗比ＳＰＣ在某些工况下降低达２０％。对两者的循环作了理论分析。     

Performance assessment of contact heat pump drying

A comparative analysis is presented of a novel plate‐type isothermal heat pump dryer and a conventional adiabatic heat pump dryer. The energy performance and drying capacity of each dryer type is investigated subject to operational constraints on the maximum acceptable relative humidity and temperature of air passing over the product. The analysis demonstrates that for applicable products, a significant opportunity exists for improving the energy efficiency of heat pump drying, by a factor of 2–3 times compared with current adiabatic heat pump dryers. The moisture extraction rate is also increased in the contact heat pump dryer, by a similar factor. However, these improvements are shown to be sensitive both to the impact of product thickness on heat transfer and to the relative humidity constraint. Copyright © 2010 John Wiley & Sons, Ltd.     

Evaluation of energy efficiency standards for residential clothes dryers in the USA

This article describes the analysis of monetary and energy savings attributable to various energy efficiency levels considered as potential US federal standards for residential clothes dryers. The analysis examined benefits to both consumers and the nation as a whole. Benefits to consumers were evaluated based on the life-cycle cost of affected appliances and the payback period associated with increased first costs. Benefits to the nation incorporate both energy and financial savings associated with each potential efficiency standard. The analysis incorporated the most current information on field use of clothes dryers, which shows that dryer usage and the moisture in clothes are less than previously thought. The analysis found that high-efficiency heat pump clothes dryers would be cost-effective for nearly one fifth of US households. However, for both electric standard and gas clothes dryers, standards that improve efficiency by 5 % appear to be the highest levels that have a positive net present value of consumer benefit.     

Review of solar assisted heat pump drying systems for agricultural and marine products

Combining solar energy and heat pump technology is a very attractive concept. It is able to eliminate some difficulties and disadvantages of using solar dryer systems or solely using heat pump drying separately. Solar assisted heat pump drying systems have been studied and applied since the last decades in order to increase the quality of products where low temperature and well-controlled drying conditions are needed. This paper reviewed studies on the advances in solar heat pump drying systems. Results and observation from the studies of solar assisted heat pump dryer systems indicated that for heat sensitive materials; improved quality control, reduced energy consumption, high coefficient of performance and high thermal efficiency of the dryer were achieved. The way forward and future directions in R&D in this field are further research regarding theoretical and experimental analysis as well as for the replacement of conventional solar dryer or heat pump dryer with solar assisted heat pump drying systems and solar assisted chemical and ground source heat pump dryers which should present energy efficient applications of the technologies.     

Experimental studies of low-temperature drying by dehumidification. Part 2—Experimental

Experiments are described in which several different types of cycles and dryers are compared, and it is shown that the best performance, in terms of both drying time and energy saving, is achieved by a recirculating cycle with a hybrid dryer with a heat pump dehumidifier and supplementary resistance heating.     

Re‐circulating heat pump assisted continuous bed drying and energy analysis

Specialty crops such as ginseng, herbs and echinacea need to be dried at low temperatures (30–35°C) for product quality optimization. A drying system that is both energy efficient and preserves product quality is desired. A re‐circulating heat pump continuous bed dryer system was designed, constructed and field‐tested for this purpose. The heat pump dryer system was experimentally evaluated using several potential herbal and medicinal crops such as alfalfa, catnip, wormwood, red clover, portulaca, dandelion and ginseng. These crops were dried either in chopped, sliced or whole form, depending on the part of the plant (aerial or root). The specific moisture extraction rates (SMER) obtained for various crops were in the range of 0.06–0.61 kg kWh^?1. It took 5 days and 190 kWh of energy to reduce the average moisture content of ginseng roots below 10% (wb), while commercial dryers currently in use would take on an average 14 days and 244 kWh of energy at comparable loading rates. The re‐circulating nature of the heat pump dryer made it 22% more energy efficient and resulted in 65% reduced drying time compared to conventional dryers incorporating electric coil heaters. Copyright © 2005 John Wiley & Sons, Ltd.     

Review of solar dryers for agricultural and marine products

Drying for agricultural and marine products are one of the most attractive and cost-effective application of solar energy. Numerous types of solar dryers have been designed and developed in various parts of the world, yielding varying degrees of technical performance. Basically, there are four types of solar dryers; (1) direct solar dryers, (2) indirect solar dryers, (3) mixed-mode dryers and (4) hybrid solar dryers. This paper is a review of these types of solar dryers with aspect to the product being dried, technical and economical aspects. The technical directions in the development of solar-assisted drying systems for agricultural produce are compact collector design, high efficiency, integrated storage, and long-life drying system. Air-based solar collectors are not the only available systems. Water-based collectors can also be used whereby water to air heat exchanger can be used. The hot air for drying of agricultural produce can be forced to flow in the water to air heat exchanger. The hot water tank acts as heat storage of the solar drying system.     

燃气机热泵的热力学分析

燃气机热泵是以燃气机作为动力来驱动的压缩式热泵。对燃气机热泵的热力学第一定律、Yong分析和能级平衡理论分析结果表明：其一次能源利用率可达1.76，Yong效率为0.291，能级平衡系数为0.394。与电动热泵等其他供热装置相比，燃气机热泵有着较高的热力学完善性，是一项高效节能技术。由于能级平衡理论分析考虑了Wu的作用，而热泵供暖时其性能系数的提高主要是利用了环境热量，所以建议采用能级平衡理论来分析评价热泵的性能。     

The contact factor for dryer performance and design

We describe an approach using the contact factor (CF) as the dryer performance and design parameter. The CF is calculated using known drying variables with a view to minimizing the drying costs. An algorithm to obtain the ‘economic’ CF for drying is presented. Besides being a design parameter of single‐stage dryers, the CF is a useful parameter in determining the schedule of cascade dryers in multi‐stage drying. We demonstrate the dryer component selection process using a set of design charts for heat pump dryers. Copyright © 1999 John Wiley & Sons, Ltd.