Upgrading Waste Heat from 90 to 110 °C: The Potential of Adsorption Heat Transformation. Issue 1 (9th November 2020)

• Record Type: Journal Article
• Authors: Engelpracht, Mirko; Gibelhaus, Andrej; Seiler, Jan; Graf, Stefan; Nasruddin, Nasruddin; Bardow, André
• Is Part Of: Energy technology. Volume 9:Issue 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-09
• Subjects: adsorber-bed designs -- control optimization -- heat transformation -- low-grade heat utilization -- thermal heat upgrade; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.202000643
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract : Low‐grade heat is abundantly available below 100 °C, whereas industry mainly needs heat above 100 °C. Thus, the industry cannot directly utilize low‐grade heat to save primary energy and emissions. Low‐grade heat can be utilized by adsorption heat transformers (AdHTs); however, closed AdHTs to upgrade heat above 100 °C are only investigated by idealized steady‐state analyses, which indicate the maximal theoretical performance. For evaluating the performance achievable in practice, this work studies a closed AdHT in a one‐bed configuration using dynamic simulation. For the working pair AQSOA‐Z02/H2 O, the performance is optimized via the design of the adsorber heat exchanger and the control of the AdHT cycle. When heat is upgraded from 90 to 110 °C, releasing waste heat at 35 °C, the maximum exergetic coefficient of performance (COPexergetic ) is 0.64, and the maximum specific heating power (SHP) is 590 W kg −1 . The maximum SHP can increase by 35% when releasing waste heat at 25 °C. Both performance indicators strongly depend on design, control, and the available temperature of the waste heat. Overall, AdHTs with optimized design and control are promising to utilize low‐grade waste heat. Abstract : Herein, the potential of adsorption heat transformers (AdHTs) to upgrade abundantly available low‐temperature waste heat above 100 °C is estimated. An AdHT with optimized design and control can recover up to 64% of the exergy input and offers competitive power densities. Thus, this model‐based study demonstrates the promising performance of AdHTs for exploiting waste heat around 100 °C.