Next-generation ammonia adsorption heat pump cycles and technology 1=Energy 2=Energy Efficiency

减少与家庭供暖有关的二氧化碳排放。一项氨-水吸收技术已商业化，具有良好的GUE（气体利用效率，出热量/气体总热值为1.4），但资本成本高。一种氨碳吸附循环正在开发中，可将GUE降低到1.2，但资本成本可承受。有两种方法可以在不增加投资成本的情况下改善吸附循环。一种是发展碳氨技术，采用多种吸附剂提高热回收率，另一种是使用化学吸附剂，通常是嵌在石墨基体中的卤化物盐，用于再吸收循环。这两者都是华威大学的初步研究课题。研究方案将首先进行充分的分析和建模，以决定哪种活性炭或金属卤化物吸附剂具有更大的最终商业采用潜力。碳吸附剂当然可以达到1.4的GUE，但代价是一些额外的复杂性。金属盐路线的技术准备水平较低，但理论上可以在两盐循环中提供1.5的GUE，在三盐循环中提供2.0的GUE。这两种技术所面临的挑战有些不同。碳吸附剂已被很好地表征和理解。难点在于低热质量、传热传质好、成本低的碳氨吸附器的构建；这已经是多年努力的主题。采用先进热回收技术的多床床进一步增加了设计和模拟的复杂性。金属盐系统中的吸附剂非常不同，因为盐包含在导电（非吸附）石墨基体中，从而提高了导电性。再吸收循环也有较少组分的好处。然而，发生的化学反应更有问题，反应速率很难预测。在碳-氨机器中，活性炭总是处于化学平衡状态，并且操作受到传热限制，在金属盐-氨系统中，永远不会存在平衡状态，并且操作性能取决于尚不了解的反应速率动力学。在两种相互竞争的技术之间做出选择（预计在9月之前），研究将进入详细的设计和模拟阶段，在此阶段，使用华威大学已经建立的大温度跳变（LTJ）技术，在“单元”水平上评估拟议的吸附器设计。随着吸附器设计的验证，将开始建造概念验证机（3-10千瓦输出），并开始模拟控制策略。POC机器将首先在ThermExS实验室进行测试，该实验室是在EPSRC资金资助下专门建造的，旨在轻松评估新型热力学系统。它由四个计算机控制的热浴池，阀门和泵组件组成，作为热源和水槽，温度从-10到180摄氏度，功率从7到30千瓦。这种水平的测试，电加热，在实验室内足以证明所选的循环/吸附剂，并产生值得博士学位的新知识。然而，很有可能在这个时候，华威大学将有新的资助项目，使这项工作更进一步，也许在一个独立的系统中集成一个燃气燃烧器。

in reducing the CO2 emissions associated with domestic heating. One ammonia - water absorption technology is commercialised, with good GUE (Gas Utilisation Efficiency, heat out/gross calorific value of gas in of c. 1.4) but high capital cost. An ammonia - carbon adsorption cycle is under development, offering reduced GUE of 1.2 but affordable capital cost. Two possibilities exist to improve the adsorption cycle GUE without a major increase in capital cost. One is a development of the carbon ammonia technology employing either multiple adsorbers with improved heat recovery and the other using chemical adsorbents, generally halide salts embedded in a graphite matrix and used in resorption cycles. Both have been the subject of preliminary work at Warwick.The research programme will first undertake sufficient analysis and modelling to decide which of either the active carbon or metal halide adsorbent types has the greater potential for eventual commercial adoption. The carbon adsorbent can certainly achieve a GUE of 1.4 at the expense of some extra complexity. The metal salt route is lower Technology Readiness Level but in theory could offer a GUE of 1.5 in a two-salt cycle and 2.0 in a three-salt cycle.The challenges presented by the two technologies are somewhat different. The carbon adsorbent is well characterised and understood. The difficulties are in construction of a carbon ammonia adsorber with low thermal mass, good heat and mass transfer and low cost; this has already been the subject of many years' effort. A multiple bed with advanced heat recovery introduces further complexities in design and simulation. The adsorbers in a metal salt system are very different in that the salts are contained within a conductive (non-adsorbing) graphite matrix which improves conductivity. The resorption cycles also have the benefits of fewer components. However, the chemical reactions that take place are much more problematic with reaction rates very difficult to predict. Where the active carbon in the carbon-ammonia machines is always in chemical equilibrium and operation is heat transfer limited, within metal salt - ammonia systems there is never equilibrium and operational performance depends on the poorly understood reaction rate dynamics.Having made a choice between the two competing technologies (expected by Month 9) the research will enter a detailed design and simulation phase in which proposed adsorber designs are evaluated at 'unit-cell' level using the Large Temperature Jump (LTJ) technique already established at Warwick. With the validation of the adsorber design, construction of a proof of concept machine (3-10 kW output) will commence and simulation of control strategies begun. The POC machine will be tested first in the ThermExS laboratory, purpose-built under an EPSRC capital grant for the easy evaluation of novel thermodynamic systems. It consists of four computer-controlled thermal baths, valve and pump assemblies that act as heat sources and sinks from -10 to 180 C and powers from 7 to 30 kW.This level of testing, electrically heated and within the laboratory is sufficient to prove the chosen cycle/adsorbents and result in new knowledge worthy of a PhD. However, it is quite probable that by this time there will be newly funded projects at Warwick that will enable the work to go further, perhaps integrating with a gas burner in a stand-alone system.