Tunable Low-Pressure Water Adsorption in Stable Multivariate Metal-Organic Frameworks for Boosting Water-Based Ultralow-Temperature-Driven Refrigeration.

The green water-based adsorption refrigeration is considered as a promising strategy to realize near-zero-carbon cooling applications. Although many metal-organic frameworks (MOFs) have been developed as water adsorbents, their cooling performance are commonly limited by the insufficient water uptakes below P/P0 = 0.2. Herein, the development of multivariate MOFs (MTV-MOFs) is reported to highly modulate and boost the low-pressure water uptake for improving coefficient of performance (COP) for refrigeration. Through ligand exchange in the pristine MIL-125-NH2 , a series of MTV-MOFs with bare nitrogen sites are designed and synthesized. The resulting MIL-125-NH2 /MD-5% exhibits the significantly improved water uptake of 0.39 g g-1 at 298 K and P/P0 = 0.2, which is three times higher than MIL-125-NH2 (0.12 g g-1 ) and comparable to some benchmark materials including KMF-1 (0.4 g g-1 ) and MIP-200 (0.36 g g-1 ). Combined with its low-temperature regeneration, fast sorption kinetics and high stability, MIL-125-NH2 /MD-5% achieves one of the highest COP values (0.8) and working capacities (0.24 g g-1 ) for refrig-2 under an ultralow-driven temperature of 65 °C, which are higher than some best-performing MOFs such as MIP-200 (0.74 and 0.11 g g-1 ) and KMF-2 (0.62 and 0.16 g g-1 ), making it among the best adsorbents for efficient ultralow-temperature-driven refrigeration.

Immobilization of Lewis Basic Nitrogen Sites into a Chemically Stable Metal-Organic Framework for Benchmark Water-Sorption-Driven Heat Allocations.

Developing efficient and stable water adsorbents for adsorption-driven heat transfer technology still remains a challenge due to the lack of efficient strategies to enhance low-pressure water uptakes. The authors herein demonstrate that the immobilization of Lewis basic nitrogen sites into metal-organic frameworks (MOFs) can improve water uptake and target benchmark coefficient of performances (COPs) for cooling and heating. They present the water sorption properties of a chemically stable MOF (termed as Zr-adip), designed by incorporating hydrophilic nitrogen sites into the adsorbent MIP-200. Zr-adip exhibits S-shaped sorption isotherms with an extremely high water uptake of 0.43 g g-1  at 303 K and P/P0  = 0.25, higher than MIP-200 (0.39 g g-1 ), KMF-1 (0.39 g g-1 ) and MOF-303 (0.38 g g-1 ). Theoretical calculations reveal that the incorporated N sites can serve as secondary adsorption sites to moderately interact with water, providing more binding sites to strengthen the water binding affinity. Zr-adip achieves exceptionally high COPs of 0.79 (cooling) and 1.75 (heating) with a low driving temperature of 70 °C, outperforming MIP-200 (0.78 and 1.53) and KMF-1 (0.75 and 1.74). Combined with its ultrahigh stability, excellent cycling performance, and easy regeneration, Zr-adip represents one of the best water adsorbents for adsorption-driven cooling and heating.

Data of the design of solar assisted district cooling systems.

The collected datasets are relevant and related to Optimization of Design and Operation of Solar Assisted District Cooling Systems [1] paper. Part of the data is collected on the main and common components of the system. That includes solar collectors unit price ($/m2), type, and efficiency; absorption chiller capacity (kW), type, initial cost ($), and COP; the hot/chilled water thermal energy storage tank type, initial cost ($) and capacity (kWh); and auxiliary boiler initial cost ($), capacity (kW), type and efficiency. The other part of the data is collected on hourly cooling demand over the year for the state of Qatar (kW), hourly global solar irradiance over the year for the state of Qatar (W/m2) and variable cost of producing and storing chilled and hot water ($/kWh, $/kW). The data are collected from different resources such as government websites, commercial websites, government sectors, journals and real-life case studies. The value of this data comes from that most of the data required to conduct such research in this area are available in one resource. Also, some of the data such as the annual hourly cooling demand and global solar radiation are not available online. Moreover, the collected data are already filtered and the units are consistent and ready to be used. Finally, the data considered to be crucial and the core of such research are available in this paper.

In Silico Screening of Metal-Organic Frameworks for Adsorption-Driven Heat Pumps and Chillers.

A computational screening of 2930 experimentally synthesized metal-organic frameworks (MOFs) is carried out to find the best-performing structures for adsorption-driven cooling (AC) applications with methanol and ethanol as working fluids. The screening methodology consists of four subsequent screening steps for each adsorbate. At the end of each step, the most promising MOFs for AC application are selected for further investigation. In the first step, the structures are selected on the basis of physical properties (pore limiting diameter). In each following step, points of the adsorption isotherms of the selected structures are calculated from Monte Carlo simulations in the grand-canonical ensemble. The most promising MOFs are selected on the basis of the working capacity of the structures and the location of the adsorption step (if present), which can be related to the applicable operational conditions in AC. Because of the possibility of reversible pore condensation (first-order phase transition), the mid-density scheme is used to efficiently and accurately determine the location of the adsorption step. At the end of the screening procedure, six MOFs with high deliverable working capacities (∼0.6 mL working fluid in 1 mL structure) and diverse adsorption step locations are selected for both adsorbates from the original 2930 structures. Because the highest experimentally measured deliverable working capacity to date for MOFs with methanol is ca. 0.45 mL mL-1, the selected six structures show the potential to improve the efficiency of ACs.

Scalable Green Synthesis and Full-Scale Test of the Metal-Organic Framework CAU-10-H for Use in Adsorption-Driven Chillers.

The demand for cooling devices has increased during the last years and this trend will continue. Adsorption-driven chillers (ADCs) using water as the working fluid and low temperature waste energy for regeneration are an environmentally friendly alternative to currently employed cooling devices and can concurrently help to dramatically decrease energy consumption. Due to the ideal water sorption behavior and proven lifetime stability of [Al(OH)(m-BDC)] ∙ x H2 O (m-BDC2- = 1,3-benzenedicarboxylate), also denoted CAU-10-H, a green very robust synthesis process under reflux, with high yields up to 95% is developed and scaled up to 12 kg-scale. Shaping of the adsorbent is demonstrated, which is important for an application. Thus monoliths and coatings of CAU-10-H are produced using a water-based binder. The composites are thoroughly characterized toward their mechanical stability and water sorption behavior. Finally a full-scale heat exchanger is coated and tested under ADC working conditions. Fast adsorption dynamic leads to a high power output and a good power density. A low regeneration temperature of only 70 °C is demonstrated, allowing the use of low temperature sources like waste heat and solar thermal collectors.

Instrumentation for analytical scale supercritical fluid chromatography.

Analytical scale supercritical fluid chromatography (SFC) is largely a sub-discipline of high performance liquid chromatography (HPLC), in that most of the hardware and software can be used for either technique. The aspects that separate the 2 techniques stem from the use of carbon dioxide (CO2) as the main component of the mobile phase in SFC. The high compressibility and low viscosity of CO2 mean that pumps, and autosamplers designed for HPLC either need to be modified or an alternate means of dealing with compressibility needs to be found. The inclusion of a back pressure regulator and a high pressure flow cell for any UV-Vis detector are also necessary. Details of the various approaches, problems and solutions are described. Characteristics, such as adiabatic vs. isothermal compressibility, thermal gradients, and refractive index issues are dealt with in detail.

Pré-resfriamento na redução de coliformes em carcaças de frango de corte / Immersion chilling in fecal coliforms count reduction on broiler carcasses

O objetivo deste trabalho foi comparar a análise individual (plano de duas classes) e a análise por lotes (plano de três classes), priorizado pelo plano amostragem oficial da ANVISA, na influência do pré-resfriamento de carcaças de frangos de corte na redução da contaminação por coliformes termotolerantes. Foram analisadas 240 carcaças de frangos de corte, sendo coletadas 120 amostras antes e 120 após a etapa de pré-resfriamento, para quantificação de coliformes termotolerantes pela técnica de contagem em placas. As médias das contagens obtidas das carcaças coletadas antes e após o pré-resfriamento foram diferentes, com uma redução média de 0,99log10 UFC g-1 de coliformes termotolerantes. Na interpretação dos resultados obtidos antes do pré-resfriamento pela análise individual, 16,7% (20/120) das carcaças foram classificadas como inaceitáveis, enquanto, pela análise por lotes, foram 37,5% (45/120). Houve associação entre a aceitabilidade dos lotes e a passagem pelo chiller com um valor de Odds Ratio de 35,48. Ficou demonstrada a importância da utilização do plano de análise por lotes e da etapa de pré-resfriamento no processo de produção, sendo decisivos para a aceitação dos lotes de carcaças de aves para comercialização pelos parâmetros vigentes na legislação nacional.

The objective of this study was to assess the influence of immersion chilling on broiler carcasses contamination by fecal coliforms counting in a poultry slaughterhouse under Federal Sanitary Inspection by individual and three class plan interpretation of the results. Two hundred and forty broiler carcasses, being collected 120 before and 120 after passage thought chillers, were analyzed for coliform counting by plate count technique. The averages of the counts obtained from all carcasses collected before and after immersion chilling were different, with an average reduction of 0.99log10 CFU g-1 of fecal coliforms. Regarding individual results (two class plan) before chilling, 16.7% (20/120) of the carcasses were classified as unacceptable, against 37.5% (45/120) regarding lots results (three class plan). There was a strong association between the acceptability of lots and immersion chilling with an Odds Ratio value of 35.48. It was demonstrated the importance of the official sampling plan and immersion chilling in the production process, being decisive for the acceptance of the chicken carcass lots by the national legislation standards.