This work presents ALCHEMIA for the augmented integration of commercial process simulation software with LCA software.

Adsorption chillers often employ the refrigerant water despite its two challenges: (1) The temperature limitation due to its freezing point and (2) the need to evaporate at low pressure for typical cool temperatures in cooling applications. These challenges can be addressed individually: Anti-freezing agents help to overcome challenge (1), while capillary-assisted thin-film evaporation can mitigate the static pressure issue associated with challenge (2). However, the combination of both measures remains to be explored. Hence, this study investigates the heat transfer during evaporation of water as primary refrigerant, ethanol as anti-freezing agent, and their mixtures on finned tubes exploiting capillary action. The results show that capillary-assisted thin-film evaporation can also be exploited for ethanol and water-ethanol mixtures. Ethanol can achieve overall heat transfer coefficient U comparable to water, while U-values of water-ethanol mixtures decreased up to 51%. The most likely reason for the heat transfer deterioration are mass transfer resistances due to increased viscosity of water-ethanol mixtures. These results provide insights into the heat transfer of alternative refrigerants to expand the cooling temperature of adsorption chillers.

Carbon capture, utilization, and storage is crucial for climate change mitigation. As carbon dioxide (CO2) source and sink locations typically do not coincide, efficient CO2 transport solutions are essential. Since installing transport infrastructure requires substantial investments, researchers and decision-makers need to know the long-term evolution of the resulting environmental impacts, and the implications for a gigatonnescale deployment of CO2 transport. Here, we quantify the environmental impacts of CO2 transport modes in Europe up to 2100 via prospective life cycle assessment. Our results confirm that dense phase pipelines result in the lowest environmental impacts for both on-and offshore CO2 transport today and in the future, despite substantial improvements in truck, train, barge, and ship transport towards 2100. Even for a gigatonne-scale CO2 pipeline transport network in Europe, all 16 studied environmental impact categories are expected to be less than 0.075% of Europe's share of the safe operating space based on population. After pipelines, trains and electric trucks impact the climate the least. However, batch-wise onshore transport can exacerbate freshwater ecotoxicity, particulate matter formation, and metal/mineral depletion. Switching from batch-wise to dense phase pipeline transport can pay back the required carbon investment within less than three years. Our analysis, thus, identifies environmentally preferable CO2 transport modes that are robust for future deployment towards gigatonne-scale carbon capture, utilization, and storage supply chains.

Carbon capture, transport, and storage (CCTS) enables the decarbonization of industrial emitters. CCTS is regarded as crucial in reaching net-zero emission targets but currently stands far behind the required scale. CCTS deployment for point sources may be accelerated by CCTS chains relying on currently available technology, called pioneering supply chains. In particular, transporting CO2 in standard containers can be implemented without new transport infrastructure. Pioneering CCTS chains must not cause more emissions than they store to successfully avoid CO2 emissions. Using life cycle assessment, we show that pioneering CCTS chains emit less CO2 than they store permanently, demonstrating that CCTS can already today avoid 50 to 70% of point source GHG emissions. This evidence proves robust against uncertainties based on the scarce operational experience in CCTS. Our environmental assessment shows that increasing the capture rate above the assumed 90% is a main lever to increase emissions avoidance of the CCTS chains above 80%. Capturing and transporting the CO2 causes large shares of the chain’s global warming impact as they rely on fossil fuels. Reducing GHG emission intensity of energy supply and switching to pipeline-based transport can reduce global warming and other environmental impacts compared to pioneering CCTS chains. Our analysis shows that pioneering chains can accelerate infrastructure scale-up while successfully storing CO2 from point sources.

Adsorption heat transformers (AdHTs) have recently been proposed to decarbonize industrial heat supply by upgrading low-temperature waste heat to higher temperatures. An AdHT’s performance strongly depends on equilibrium and kinetic properties of the selected working pair, component and cycle designs, operating temperatures, volume flow rates, and phase times. Exploring this multi-dimensional design space requires a validated full-scale dynamic AdHT model. Due to the lack of such a model, the optimal design and achievable performance of AdHTs are unknown. Here, we address this gap in two steps: First, we developed, calibrated, and validated a dynamic AdHT model for our one-bed prototype, which uses silica gel 123 & water. The model accurately predicted thermal efficiency and power density, with average deviations below 8.1% from measurements. Second, we successively optimized the process design for heat upgrading from 90 to 110 °C and releasing condensation heat at 25 °C. Improvements in the component designs increased the maximal thermal efficiency by 117 % to 0.35 J(th)J(th)−1 (43 % of the maximal Carnot efficiency) and the maximal power density by 79 % to 304 Wkg−1. Vapor mass recovery increased thermal efficiency the most. Combined heat and vapor mass recovery increased power density the most. The resulting AdHT also achieved an electrical efficiency of up to 40 J(th)J(el)−1. Thus, an AdHT can compete with a high-temperature heat pump from a thermodynamic perspective, encouraging further research into AdHTs.

Adsorption chillers are a promising technology to ease the burden on renewable electricity demand by using waste heat as driving energy. Their performance depends on the adsorbent's kinetics, the chosen refrigerant, the design of the adsorber, and the selected temperatures. Thus, quantifying an adsorption chillers' performance usually requires expensive experiments at full scale. Here, we efficiently characterize a broad set of working pairs for a wide range of conditions using a two-step approach: First, we conducted Large-Temperature-Jump and equilibrium experiments to extract kinetic and equilibrium parameters of water, ethanol, and methanol with a set of currently discussed adsorbents. Second, we inserted the parameters into a dynamic Modelica model to evaluate the working pairs' performance in full-scale two-bed adsorption chillers. For chilling above 0 degrees C, water remains the benchmark refrigerant with the highest volumetric power and efficiency with the silica gels SG123 and Siogel. Ethanol and methanol working pairs offer higher mass transfer coefficients, but could not offset the benefits of water. Coatings of the MOFs aluminum fumarate and CAU-10-H provided exceptionally high heat transfer coefficients, but were too thin to compete. For chilling below 0 degrees C, ethanol and methanol were on par. ZIF-8 was competitive with the activated carbon CarboTech A35. Overall, CarboTech A35/methanol showed broad applicability, performing comparably to SG123/water above 0 degrees C while still providing reasonable performance below 0 degrees C.

Adsorption chillers are a promising technology for sustainable cooling. The performance of adsorption chillers is highly influenced by the selection of the refrigerant. Still, systematic selection of refrigerants is challenging because evaluating adsorption properties requires significant experimental or simulation efforts. Thus, refrigerant design options are often limited.Here, we propose a systematic refrigerant design method for adsorption chillers assessing refrigerants based on their process performance. Our method quantifies adsorption isotherms by 1-dimensional classical density functional theory (DFT) based on the PC-SAFT equation of state. The method is used to screen over 1800 refrigerants based on their coefficient of performance (COP). We identify refrigerants with higher COPs than commonly used refrigerants and highlight the advantage of a process-based objective function over material-based heuristic selection criteria. Finally, we advance from screening to computer-aided molecular design of the refrigerant, leveraging the efficiency of the DFT model to explore the molecular design space systematically.

Adsorption is at the heart of many processes from gas separation to cooling. The design of adsorption-based processes requires equilibrium adsorption properties. However, data for adsorption equilibria are limited, and therefore, a model is desirable that uses as little data as possible for its parametrization, while allowing for data interpolation or even extrapolation. This work presents a physics-based model for adsorption isotherms and other equilibrium adsorption properties. The model is based on one-dimensional classical density functional theory (1D-DFT) and the perturbed-chain statistical associating fluid theory (PC-SAFT). The physical processes inside the pores are considered in a thermodynamically consistent approach that is computationally efficient. Once parametrized with a single isotherm, the model is able to extrapolate to other temperatures and outperforms the extrapolation capabilities of state-of-the-art models, such as the empirical isotherm models from Langmuir or Toth. Furthermore, standard combining rules can be used to transfer parameters adjusted to an adsorbent/fluid pair to other fluids. These features are demonstrated for the adsorption of N2, CH4, and CO2 in metal-organic frameworks. Thereby, the presented model can calculate temperature-dependent isotherms for various fluids by using data limited to a single isotherm as input.

Metal-organic frameworks (MOFs) can be beneficial for heat transformation applications due to their potentially high water uptake and tunable working temperature levels. Although the hydrothermal stability has been assessed in some cases in terms of maximum water uptake and structural changes (XRD), there is no data on the impact of hydrothermal stress tests on sorption dynamics. However, to maintain the designed heating or cooling power in the application, the hydrothermal stability in terms of both water uptake and sorption dynamics is decisive. To close this gap, we present a novel method and experimental data for the comprehensive evaluation of hydrothermal stability for three different MOFs and the commercially available zeotype TiAPSO. The hydrothermal stress test includes around 70,000 temperature swing cycles on aluminium sheets with a binder-based coating of different adsorbents. Adsorption dynamics are determined before and after the hydrothermal stress test using effective thermal resistances and the characteristic temperature difference. Our results show degradation in terms of a decrease in uptake around 5-10% after hydrothermal stress test for all samples. Under temperature boundary conditions relevant for the application, MIL-160(Al) shows even a drastic uptake reduction of around 35-45%. Except for CAU-10-H, none of the adsorbents show a degradation in terms of increased heat and mass transfer resistance. In case of CAU-10-H, the overall effective heat and mass transfer resistance increases by around 30-40% after the hydrothermal stress test. These results indicate that the hydrothermal stability of MOFs must be assessed in terms of both, uptake and sorption dynamics, to ensure stable long-term performance in real-world devices.

Adsorption chillers can avoid two types of greenhouse gas emissions from conventional cooling technologies: energy‐related emissions by utilizing waste heat and refrigerant leakage‐related emissions by employing the natural refrigerant water. However, water restricts the minimal cooling temperature to its freezing point. To overcome this limitation, herein, a boiling antifreeze in adsorption chillers is proposed. For this purpose, a databank of over 12 000 molecules for suitable antifreezes is screened and ethanol is derived as the best candidate. Employing ethanol as antifreeze, the experimental feasibility in a lab‐scale adsorption chiller is demonstrated: ethanol can prevent freezing at a cooling temperature of –5 °C and, thus, extend the operating range of the adsorption chiller. Thereby, the favorable properties of water can be partially retained. Furthermore, water–ethanol mixtures to pure water at a cooling temperature of 10 °C are compared: maximal coefficient of performance (COP) and specific cooling power (SCP) decrease by 45% and 42%, respectively, when 14 mol% ethanol is used instead of pure water. Herein, the influence of ethanol on the adsorbed mass and heat transfer during evaporation are crucial. In summary, boiling antifreezes can extend the operating range of water‐based adsorption chillers below 0 °C.

Large amounts of waste heat, below 120 °C, are released globally by industry. To convert this low‐temperature waste heat to power, thermally regenerative flow batteries (TRFBs) have recently been studied. Most analyses focus on either the discharging or the regeneration phase. However, both phases have to be considered to holistically assess the performance of the flow battery. Therefore, a dynamic, open‐access, full‐cycle model of a Cu–NH3 TRFB is developed in Modelica and validated with data from the literature. Based on the validated model, a trade‐off between power density and efficiency is shown that depends only on the discharging strategy of the flow battery. For a sensible heat source with an inlet temperature of 120 °C and heat transfer at a thermodynamic mean temperature of about 90 °C, the power density reaches 38 W m−2 over a complete cycle, and the efficiency reaches 20% of Carnot efficiency. In a benchmarking study, the power production of the flow battery is shown to already achieve 34% of a fully optimized organic Rankine cycle. Thus, TRFBs require further optimization to become a competitive technology for power production and energy storage from low‐temperature waste heat.

Industrial energy efficiency can be increased by recovering waste heat, mainly available below 100 °C. This low‐temperature waste heat can drive adsorption heat transformers (AdHTs) to upgrade waste heat to industrially relevant temperatures above 100 °C. Flexible process integration can be achieved by decoupling adsorptive and heat transfer fluid in closed‐loop cycles. However, the experimental feasibility of closed‐loop AdHTs has not been shown yet. Hence, this work studies an experimental one‐bed setup of an AdHT based on a closed‐loop cycle using silica gel 123 and water as the working pair. Experimental feasibility is demonstrated for heat transformation from 90 to 110 °C with waste heat released at 25 °C. The highest coefficient of performance (COP) is 0.183 J J−1 (23% of the maximum Carnot efficiency), and the highest specific heating power (SHP) is 168 W kg−1. A systematic variation of the operating conditions shows that efficiency COP and power density SHP strongly depend on the operating temperatures, volume flows, and phase times. Furthermore, avoiding condensation inside the adsorber casing and heat losses are identified to be crucial for the design of AdHTs. In summary, AdHTs based on a closed‐loop cycle show a promising performance to recover low‐temperature waste heat.

Download This Paper Open PDF in Browser Add Paper to My Library Share: Permalink Using these links will ensure access to this page indefinitely Copy URL Environmental impact of pioneering carbon capture, transport and storage chains 8 Pages Posted: 15 Nov 2022 See all articles by Johannes BurgerJohannes BurgerInstitute of Energy and Process Engineering, ETH ZurichJulian NöhlInstitute of Energy and Process Engineering, ETH ZurichJan SeilerInstitute of Energy and Process Engineering, ETH ZurichPaolo GabrielliETH Zurich - Institute of Energy and Process EngineeringGiovanni SansaviniETH Zurich - Institute of Energy and Process EngineeringAndré BardowETH Zürich Date Written: August 26, 2022 Abstract The transition to net-zero emissions requires large amounts of carbon dioxide to be captured and stored permanently in geological storage. To initiate the large-scale deployment of CO2 capture, transport, and storage (CCTS) value chains, immediate deployment of infrastructure is required. The environmental impacts of a value chain relying on ready-to-use technologies instead of optimal ones with long lead times, such as pipelines, is so far unclear. We assess the environmental impacts through the life cycle assessment of an exemplary CCTS value chain from Switzerland to Norway that only uses immediately available technologies. Even though the system relies on suboptimal technologies and is not optimized for a low climate impact, it shows the capability to effectively sequester CO2 without emitting more during its life cycle than is stored. Contrary to previous studies, the ready-to-use transport modes cause a significant share (56.3 %) of the total global warming impact (GWI) of the value chain. More than 73 % of the total GWI stems from the use of fossil fuels during the operation phase of the value chain. Keywords: CCTS, CCS, Life cycle assessment, Pioneering CCTS value chains, CCTS supply chains Suggested Citation: Suggested Citation Burger, Johannes and Nöhl, Julian and Seiler, Jan and Gabrielli, Paolo and Sansavini, Giovanni and Bardow, André, Environmental impact of pioneering carbon capture, transport and storage chains (August 26, 2022). Available at SSRN: https://ssrn.com/abstract=4276719 Johannes Burger Institute of Energy and Process Engineering, ETH Zurich ( email ) ZurichSwitzerland Julian Nöhl Institute of Energy and Process Engineering, ETH Zurich Zürichbergstrasse 188092 Zurich, CH-1015Switzerland Jan Seiler Institute of Energy and Process Engineering, ETH Zurich Zürichbergstrasse 188092 Zurich, CH-1015Switzerland Paolo Gabrielli ETH Zurich - Institute of Energy and Process Engineering ( email ) Leonhardstrasse 21Zurich, Zurich 8092Switzerland Giovanni Sansavini ETH Zurich - Institute of Energy and Process Engineering ( email ) Sonneggstrasse 3ZURICH, 8092Switzerland André Bardow (Contact Author) ETH Zürich Energy and Process Systems EngineeringETHZürich, Zürich 8092Switzerland Download This Paper Open PDF in Browser Do you have a job opening that you would like to promote on SSRN? Place Job Opening Paper statistics Downloads 2 Abstract Views 3 PlumX Metrics Related eJournals 16th Greenhouse Gas Control Technologies Conference 2022 (GHGT-16) Follow 16th Greenhouse Gas Control Technologies Conference 2022 (GHGT-16) Subscribe to this free journal for more curated articles on this topic FOLLOWERS 36 PAPERS 0 Feedback Feedback to SSRN Feedback (required) Email (required) Submit If you need immediate assistance, call 877-SSRNHelp (877 777 6435) in the United States, or +1 212 448 2500 outside of the United States, 8:30AM to 6:00PM U.S. Eastern, Monday - Friday. Submit a Paper Section 508 Text Only Pages SSRN Quick Links SSRN Solutions Research Paper Series Conference Papers Partners in Publishing Jobs & Announcements Newsletter Sign Up SSRN Rankings Top Papers Top Authors Top Organizations About SSRN SSRN Objectives Network Directors Presidential Letter Announcements Contact us FAQs Copyright Terms and Conditions Privacy Policy We use cookies to help provide and enhance our service and tailor content. To learn more, visit Cookie Settings. This page was processed by aws-apollo-4dc in 0.398 seconds

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/H2O, 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.

Capillary-assisted thin-film evaporation is a promising approach to overcome the heat transfer challenges associated with sub-atmospheric evaporation of water in refrigeration applications. Consequently, thin-film evaporation is currently studied in several labs. However, so far it has been unclear whether results from different labs can be compared. In this work, we therefore investigate - for the first time - the impact of experimental setups and procedures on sub-atmospheric capillary-assisted thin-film evaporation of the refrigerant water and deduce methodological recommendations for improving reliability and comparability of measurement results. We present results of evaporation from finned copper tubes with decreasing filling levels from two different experimental setups: At higher driving force, the resulting dynamics of logarithmic mean temperature differences, heat flows and overall heat transfer coefficients determined in both setups are generally in good agreement but absolute values show deviations of up to 24%. For lower driving forces, the results are identical within uncertainty of measurement. We conclude that the impact of experimental setup is important when comparing absolute values from different setups, but obtaining comparable results is generally possible. Furthermore, we compare experiments with continuously decreasing versus constant filling levels and show that both procedures yield the same results within measurement uncertainty. With decreasing filling level, however, overall heat transfer coefficients are systematically 5-10% higher. Thus, experiments with continuously decreasing filling level are well-suited for a fast analysis of all filling levels in a single experiment.

Efficient evaporation of water at low temperatures is challenging due to its low saturation pressure. As a consequence, the preferred evaporation by nucleate boiling can only be achieved at the cost of high superheats. However, low superheats can still lead to efficient evaporation by thin-film evaporation. In this work, we experimentally characterize the heat transfer for thin-film evaporation on coated copper tubes, which use capillary action to create a thin film on their surface. The overall heat transfer through the tubes is determined at all filling levels for evaporator inlet temperatures of 10, 15 and 20 degrees C with varied driving force. Our experiments reveal that poor coatings suffer from dry-out at high driving forces whereas tubes with good coatings remain fully wetted even at high driving force. Furthermore, we show the impact of surface properties on thin-film evaporation: high porosity, surface extension and roughness promote the creation of a thin film on the tube. Thereby, the heat transfer UA-value is increased up to a factor of 10.

The control strategy strongly influences the performance of adsorption chillers: efficiency and power density depend on phase times for adsorption and desorption. The optimal phase times depend on system characteristics, inlet conditions, and user's preferences regarding the trade-off between efficiency and power density. In principle, these optimal phase times can be determined during operation using nonlinear model predictive control (NMPC), but implementation is complex and, therefore, still missing. In this paper, we propose and implement a NMPC strategy at an adsorption-chiller test stand and experimentally evaluate the performance. The NMPC strategy combines a nonlinear process model, state estimation, phase time optimisation, and prediction of future inlet conditions. The NMPC is experimentally tested for two scenarios: (1) a step in desorption inlet temperature and (2) a typical solar-cooling application. Comparison with a typical state-based control shows that NMPC can increase the specific cooling power by 31.1%.