Membrane-based absorption heat pumps (MAHP) operate based on the working principle of the absorption refrigeration system (ARS), which could be used to recover and transform low-temperature waste heat into useable heat sources with higher temperatures. This work focuses on the performance study of a counter-flow parallel-plate membrane-based absorption heat pump (PMAHP) to recover low-temperature waste heat from used cooling water at 40 °C. It consists of refrigerant (water) and absorbent (LiCl solution) streams flowing in neighboring channels formed by hydrophobic microporous membranes with air gaps sandwiched in between these channels. Air-gap design is incorporated to minimize the sensible heat loss through conduction between the two streams. Water vapor molecules travel from the water stream to the solution stream through the membrane and air gaps. As the water molecules are absorbed by the solution, they condense to release the latent heat of absorption and dilution. The recovered heat can be used subsequently for fluid heating or air-conditioning purposes. A three-dimensional, steady-state model based on the finite element method is used to study the conjugate heat and mass transfer mechanisms. Model validation results agree with experimental data with a general discrepancy of within 10%. Parametric studies on the performance of the PMAHP are carried out. Scaling analysis is applied to study the effects of geometrical parameters on the heat and mass transfer dimensionless parameters, fluid flow behavior, heat, and mass transport within the PMAHP. The optimal air gap width is determined to achieve maximum solution temperature lift, which shows an improvement of 99.6% compared to the base case. The findings of this study provide an insight regarding the potential aspects to be focused on for further enhancement in the PMAHP heat and mass transfer performance.

膜吸收式热泵 (MAHP) 基于吸收式制冷系统 (ARS) 的工作原理运行，可用于回收低温废热并将其转化为可用的高温热源。这项工作的重点是逆流平行板膜基吸收式热泵 (PMAHP) 的性能研究，用于从 40 °C 的使用过的冷却水中回收低温废热。它由在相邻通道中流动的制冷剂（水）和吸收剂（氯化锂溶液）流组成，这些通道由疏水性微孔膜形成，这些通道之间夹有气隙。结合气隙设计，通过两股气流之间的传导最大限度地减少显热损失。水蒸气分子从水流穿过膜和气隙到达溶液流。当水分子被溶液吸收时，它们会凝结以释放吸收和稀释的潜热。回收的热量随后可用于流体加热或空调目的。基于有限元方法的三维稳态模型用于研究共轭传热和传质机制。模型验证结果与实验数据一致，一般误差在 10% 以内。对 PMAHP 的性能进行了参数研究。缩放分析用于研究几何参数对 PMAHP 内的传热和传质无量纲参数、流体流动行为、热量和传质的影响。确定最佳气隙宽度以实现最大溶液温度提升，与基本情况相比提高了 99.6%。这项研究的结果提供了关于进一步提高 PMAHP 传热和传质性能的潜在方面的见解。