Combined Material and Process Development for Efficient Adsorption Heat Pumps

用于加热和冷却目的的常规热泵的运行使用的是高级电能。热驱动吸附热泵利用太阳能热发电，地热发电或工业废热是一个有趣的选择。吸附热泵的特点是固体吸附剂的加载和再生之间的循环变化，以及三个温度水平之间的运行。高热效率的条件是：1)所使用的吸附剂必须具有高的吸附容量和相对于整个过程的快速吸附动力学。材料应具有较高的内表面（微孔），并通过足够数量和排列的输送孔（宏观孔）具有良好的可达性。2)为保证吸附剂的快速加热和冷却，吸附剂的导热性应高，以实现快速和完全的温度变化。3)吸附剂（和山梨酸盐）定期加热和冷却。整个过程的一个目标是尽量减少热电荷损失。除了2)中提到的问题之外，这可以通过最小化吸附剂的热容量和减少惰性质量或在模拟吸附剂和热载体的逆流中使用多个模块进行过程控制来实现，从而导致存储热量的内部回收。4)使吸附剂和相变区（冷凝器/蒸发器）之间山梨酸流动的传递阻力最小化。可以单独优化上述每个需求，但不能同时优化所有属性。例如，一方面可以通过添加导电材料来实现吸附剂的高导热性，另一方面降低了吸附容量。单一材料性能的影响还取决于所青睐的整体工艺：具有高内部热回收的工艺（模拟逆流工艺）的效率对惰性质量的敏感性低于简单的两床工艺。到目前为止，材料和工艺开发是相互独立进行的。材料开发的目标主要是在任务1)和2)上，而工艺技术开发(3)和4)通常基于给定的和不受影响的材料的假设。由于所描述的依赖性，可以假设这种方法不会导致材料和工艺的共同优化。在提交的项目建议书中，这两项开发应协同作用，以确定材料和工艺的理想组合，并举例推导出材料和工艺技术组合设计的方法。

Exergetically high-grade electrical energy is used for the operation of conventional heat pumps for heating and cooling purpose. Thermally driven adsorption heat pumps using solar thermal power, geothermal power or industrial waste heat are an interesting alternative. Characteristic for adsorption heat pumps is the cyclic change between loading and regeneration of the solid adsorbent, and the operation between three temperature levels. Conditions for a high thermal efficiency are: 1) The adsorbent used has to have a high adsorption capacity and - relative to the whole process - fast sorption kinetics. The material should have a high inner surface (micro pores) and good accessibility through an adequate number and arrangement of transport pores (macro pores). 2) To ensure fast heating and cooling of the adsorbent the thermal conductivity of the adsorbent should be high for a fast and complete temperature change. 3) The adsorbent (and the sorbate) are heated up and cooled down periodically. One goal of the overall process is to minimize such heat charge losses. This can be achieved - in addition to the issues mentioned in 2) - by minimizing the heat capacity of the adsorbent and reduction of inert masses or a process control with multiple modules in a simulated countercurrent flow of adsorbent and heat carrier which leads to an internal recovery of stored heat. 4) Minimization of transfer resistances of the sorbate flow between adsorbent and phase change zone (condenser/evaporator). It is possible to optimize each of the aforementioned requirements taken in isolation, but not all properties simultaneously. For example, on the one hand a high thermal conductivity of the adsorbent can be achieved through the addition of conductive materials which reduces the adsorption capacity on the other hand. The influence of single material properties also depends on the favored overall process: the efficiency of a process with high internal heat recovery (simulated countercurrent process) is less sensitive against inert masses than a simple two-bed process. Material and process development is carried out independently of each other so far. Goals of material development are mainly at tasks 1) and 2) while the process technology development (3) and 4)) usually acts on the assumption of given and not influenceable materials. As a result of the described dependencies it can be assumed that this approach does not result in a common optimum of material and process. In the submitted project proposal both developments shall be brought in synergy to identify an ideal combination of material and process and exemplarily derive a methodology of combined material and process technology design.