Recent advances in adsorption heat transformation focusing on the development of adsorbent materials

Hastürk, Emrah; Ernst, Sebastian‐Johannes; Janiak, Christoph

doi:10.1016/j.coche.2018.12.011

Cited by 52 publications

(35 citation statements)

References 61 publications

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“…Suitable for AHP applications are, in particular, those porous materials which have a high water uptake (adsorption) in a narrow partial pressure range and which show little to no hysteresis. [77,89] A hysteresis will reduce the usable part of the loading and lead to loss of sensible heat. [78,79] The partial pressure at which water adsorption takes place can be adjusted by pore size and hydrophilicity.…”

Section: Theory Of Water Adsorptionmentioning

confidence: 99%

“…Expected lifetimes in real adsorption-driven heat pumps are over 100,000 ad-and desorption-cycles. [35,77] The 100,000 cycles correspond to an estimate of ten years of operation in a heat pump. [77] Cycling water sorption over thousands of cycles will be impossible without very high water stability.…”

Section: Stability Of Mofs For Water Sorptionmentioning

confidence: 99%

“…[35,77] The 100,000 cycles correspond to an estimate of ten years of operation in a heat pump. [77] Cycling water sorption over thousands of cycles will be impossible without very high water stability. The desired water stability depends on the metal and ligand building blocks.…”

Section: Stability Of Mofs For Water Sorptionmentioning

confidence: 99%

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Metal‐Organic Frameworks as Sorption Materials for Heat Transformation Processes

et al. 2020

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Cyclic physical adsorption and desorption processes on porous materials can be used for the conversion of heat in heat transformation processes, which is the working principle in adsorption heat pumps (AHPs). Environmentally benign water with its high enthalpy of evaporation is the working fluid of choice in AHPs. Metal‐organic frameworks, MOFs can adsorb large amounts of water or methanol, up to their own weight. MOFs could be alternative materials to silica gels, zeolites, or aluminum phosphates for low‐temperature heat transformations in AHPs.

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Section: Theory Of Water Adsorptionmentioning

confidence: 99%

Section: Stability Of Mofs For Water Sorptionmentioning

confidence: 99%

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Metal‐Organic Frameworks as Sorption Materials for Heat Transformation Processes

et al. 2020

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“…Concerning refrigerants, a lot of effort has been made towards the development of new adsorbent materials [31][32][33][34] and the study of their interactions with various refrigerants under a wide range of operating pressures. A good adsorbent must have [35,36] (i) a large adsorption uptake at a relatively low temperature, (ii) a lower specific heat capacity, (iii) an ability to desorb the refrigerant completely under desorption conditions, (iv) a high thermal conductivity, (v) less deterioration of adsorbent with time and (vi) a low cost. Some important adsorbents are activated carbons [37,38], silica gel [39,40], metal-organic frameworks [41,42] and composite adsorbents [43,44].…”

Section: Introductionmentioning

confidence: 99%

Steady-State Investigation of Carbon-Based Adsorbent–Adsorbate Pairs for Heat Transformation Application

et al. 2020

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In this study, the ideal adsorption cycle behavior of eight activated carbon and refrigerant pairs is evaluated. The selected pairs are KOH6-PR/ethanol, WPT-AC/ethanol, Maxsorb-III/methanol, Maxsorb-III/CO2, Maxsorb-III/n-butane, Maxsorb-III/R-134a, SAC-2/R32 and Maxsorb-III/R507a. The following cooling performance parameters are evaluated for all pairs: specific cooling energy (SCE), concentration difference (ΔW) and coefficient of performance (COP) of ideal adsorption cooling and refrigeration cycles. The evaporator temperatures for the applications of adsorption cooling and refrigeration are selected as 7 and −5 °C, respectively. It is found that the Maxsorb-III/methanol pair has shown the highest specific cooling energy and coefficient of performance in a wide range of desorption temperatures; i.e., for the adsorption cooling cycle it has SCE and COP of 639.83 kJ/kg and 0.803, respectively, with desorption temperatures of 80 °C. The KOH6-PR/ethanol and the WPT-AC/ethanol pairs also give good performances comparable to that of the Maxsorb-III/methanol pair. However, the SAC-2/R32 pair possesses a higher concentration difference than the Maxsorb-III/methanol, KOH6-PR/ethanol and WPT-AC/ethanol pairs but shows a lower performance. This is due to the lower isosteric heat of adsorption of SAC-2/R32 compared to these pairs. It is found that Maxsorb-III/methanol, KOH6-PR/ethanol and WPT-AC/ethanol are the most promising pairs for application in designing adsorption cooling and refrigeration systems.

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“…">Working PairsThe appropriate selection of the working pair was reported in [9,10] as a crucial factor influencing the COP of adsorption chillers. Therefore, much reported research is related to adsorption working pairs and their properties [10]. The most popular pairs are microporous silica gel and water, zeolite and water (including alumino-silicate zeolites) [11,12], and Y-type zeolite with methanol or ethanol combinations [9,13].…”

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Experimental Study of Performance Improvement of 3-Bed and 2-Evaporator Adsorption Chiller by Control Optimization

et al. 2019

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The main challenge facing adsorption cooling technology is low Coefficient of Performance (COP), which becomes a key factor of the commercialization of this technology. This paper presents the results of modifications, aiming to increase COP, applied to the control software of a prototype three-bed two-evaporator adsorption chiller. Changes were mainly related to the sequence of the switching valves and had no influence on the hardware of the chiller. The sequence changes enabled the introduction of heat recovery and mass regeneration. Moreover, the precooling process was improved. The applied modifications not only resulted in significant improvement of the chiller's COP, but also improved the cooperation adsorption unit heating source, which is of great importance in case of district heating supply. The improvement was also observed concerning such operational aspects as noise and vibrations. In the authors' opinion, the presented modifications can be introduced to most exploited adsorption chillers and could potentially lead to similar improvements in performance.Energies 2019, 12, 3943 2 of 17 Methods of Improving COP of Adsorption ChillerThe issue of COP improvement of adsorption chillers is the subject of much research, which focuses on two main fields of study: Improvements via hardware modification and via software modification. Hardware modifications mainly consist of the proper selection of working pairs, the optimization of the adsorption beds [8], and the general system design. Software modifications reported in the literature optimize the switching time and cycle allocation. Some of the optimization methods, like the application of heat or mass recovery, usually require both hardware and software modifications. Working PairsThe appropriate selection of the working pair was reported in [9,10] as a crucial factor influencing the COP of adsorption chillers. Therefore, much reported research is related to adsorption working pairs and their properties [10]. The most popular pairs are microporous silica gel and water, zeolite and water (including alumino-silicate zeolites) [11,12], and Y-type zeolite with methanol or ethanol combinations [9,13]. Moreover, some novel adsorption working pairs are investigated, that is (silico) aluminophosphate-water, consolidated adsorbents such as LiBr-silica-ethanol or water, CaCl 2 -silica and water, and activated carbon with ethanol, methanol or water [9].Each adsorption working pair has unique properties that make it possible to obtain good performance in the conditions considered. For example, water-based pairs cannot be applied to achieve temperatures lower than 0 • C (due to water's freezing point). Some of the adsorbates, like methanol, are harmful, and its application would probably require additional safety procedures. An overview of working pairs was presented by [14]. Other important factors which must be considered are the expense and availability of the selected adsorption working pair.

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Recent advances in adsorption heat transformation focusing on the development of adsorbent materials

Cited by 52 publications

References 61 publications

Metal‐Organic Frameworks as Sorption Materials for Heat Transformation Processes

Metal‐Organic Frameworks as Sorption Materials for Heat Transformation Processes

Steady-State Investigation of Carbon-Based Adsorbent–Adsorbate Pairs for Heat Transformation Application

Experimental Study of Performance Improvement of 3-Bed and 2-Evaporator Adsorption Chiller by Control Optimization

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