•A new combined sensible-latent heat thermal energy storage configuration is proposed.•Comparative thermal and economic analyses are presented for three different types of thermal energy storage ...configurations.•Thermocline performance of single storage tank is numerically investigated.•A comprehensive cost model is formulated to evaluate the economic feasibility.•A structured thermocline energy storage system has no concerns of thermal ratcheting.
In the current work a new thermocline combined sensible-latent heat thermal energy storage configuration is proposed as an alternative to the currently used thermal storage systems; containing solid rod structures of cheap naturally occurring material with phase change material capsules impregnated between the rods. An energy balance method coupled with an enthalpy based technique are used to develop a comprehensive transient numerical model. The numerical simulations are performed to compare the performance and the cost of the three types of thermal energy storage systems. The three thermal energy storage systems are; sensible rod structure, encapsulated phase change material and combined sensible-latent heat. The influence of different evaluation indexes on economic feasibility and the performance of thermal energy storage such as capital cost, capacity cost per kWh, axial temperature distribution, pumping work, thermocline degradation, effective discharging time and effective discharging efficiency; are analyzed. The results show that effective discharging efficiency and capacity costs for encapsulated phase change material, combined sensible-latent heat, sensible rod structure are 95%, 87%, 76% and $42/kWh, $37/kWh, $35/kWh, respectively. Moreover, the hybrid configuration exhibits a storage capacity of 78.5 kWh/m3, which is 26% higher than sensible rod structure and 22% lower than encapsulated phase change material configuration. The results of the comparative study indicate that the combined sensible-latent heat TES system seems to be a more viable option among the considered configurations due to its optimized performance and comparatively low cost. Also due to the reasons that thermal ratcheting of the storage tank is avoided and it provides stable fluid outlet temperature.
Only when the power goes off and food spoils do we truly appreciate how much we rely on refrigerators and freezers. In Refrigeration Nation, Jonathan Rees explores the innovative methods and gadgets ...that Americans have invented to keep perishable food cold—from cutting river and lake ice and shipping it to consumers for use in their iceboxes to the development of electrically powered equipment that ushered in a new age of convenience and health.
As much a history of successful business practices as a history of technology, this book illustrates how refrigeration has changed the everyday lives of Americans and why it remains so important today. Beginning with the natural ice industry in 1806, Rees considers a variety of factors that drove the industry, including the point and product of consumption, issues of transportation, and technological advances. Rees also shows that how we obtain and preserve perishable food is related to our changing relationship with the natural world. He compares how people have used the cold chain in America to other countries, offering insight into more than just what we eat. Refrigeration Nation helps explain one small part of who we are as a people.
Summary Cholesteryl ester storage disease (CESD) is caused by deficient lysosomal acid lipase (LAL) activity, predominantly resulting in cholesteryl ester (CE) accumulation, particularly in the ...liver, spleen, and macrophages throughout the body. The disease is characterized by microvesicular steatosis leading to liver failure, accelerated atherosclerosis and premature demise. Although CESD is rare, it is likely that many patients are unrecognized or misdiagnosed. Here, the findings in 135 CESD patients described in the literature are reviewed. Diagnoses were based on liver biopsies, LAL deficiency and/or LAL gene ( LIPA ) mutations. Hepatomegaly was present in 99.3% of patients; 74% also had splenomegaly. When reported, most patients had elevated serum total cholesterol, LDL-cholesterol, triglycerides, and transaminases (AST, ALT, or both), while HDL-cholesterol was decreased. All 112 liver biopsied patients had the characteristic pathology, which is progressive, and includes microvesicular steatosis, which leads to fibrosis, micronodular cirrhosis, and ultimately to liver failure. Pathognomonic birefringent CE crystals or their remnant clefts were observed in hepatic cells. Extrahepatic manifestations included portal hypertension, esophageal varices, and accelerated atherosclerosis. Liver failure in 17 reported patients resulted in liver transplantation and/or death. Genotyping identified 31 LIPA mutations in 55 patients; 61% of mutations were the common exon 8 splice-junction mutation (E8SJM−1G>A ), for which 18 patients were homozygous. Genotype/phenotype correlations were limited; however, E8SJM−1G>A homozygotes typically had early-onset, slowly progressive disease. Supportive treatment included cholestyramine, statins, and, ultimately, liver transplantation. Recombinant LAL replacement was shown to be effective in animal models, and recently, a phase I/II clinical trial demonstrated its safety and indicated its potential metabolic efficacy.
•A nonuniform Y-shaped fin is designed to improve the melting phase change.•Compared with original fin tube, complete melting time for Y-shaped tube is reduced by 21.5%.•The bottom melting time for ...all the cases take more than 50% of the total melting time.•Melting rate and temperature uniformity in PCM are improved by lower fin enhancement.
This study provides an alternative solution to the improvement on solid–liquid phase change by designing a Y-shaped fin in a nonuniform pattern along the gravity direction. A numerical model is established and validated through the present measurement and data in literature. Six cases with different Y-shaped fins and locations are designed and compared to the original straight fin case. Thermal assessments on the melting fraction, temperature field, velocity distribution, and uniformity for melting are made. Results demonstrate that the nonuniform melting features caused by the local natural convection are significantly eliminated by the novel nonuniform fin structure. The time required for melting the lower PCM is found to occupy more than 50% of the completely melting time. The accurate local heat transfer enhancement measures (bottom enhancement) are conducive to markedly reduce the full melting time by 21.5%, compared to the uniform fin pattern. Upon using finned thermal storage tank for a mobilized thermal storage truck (bare tube tank), the initial investment increases by 44.9% but the profit increases by 393.6% and the payback period reduces by 69.2%. The use of fin tube in heat storage tank can quickly obtain higher returns based on a small increase in initial investment. This work provides new insights into the understandings of the transient phase change process and the strategies for guiding the design for thermal energy storage tank.
Hydrogen is currently assessed as a future clean fuel in a hydrogen economy. However, one key problem with implementing a full‐scale hydrogen economy is hydrogen storage (as hydrogen is highly ...compressible and volatile). One solution for this problem is hydrogen geo‐storage, where compressed hydrogen is injected into geological formations, and the hydrogen can be withdrawn again at any time. However, there is a serious lack of data for realistic geologic conditions, including for hydrogen‐rock wettability, which is proven to determine injectivities, withdrawal rates, storage capacities, and containment security. We thus measured this parameter at various geo‐storage conditions. For a realistic storage scenario in a deep sandstone aquifer, we found that the rock (quartz) was weakly water‐wet or intermediate‐wet. Increasing pressure, temperature, and organic surface concentration increased hydrogen wettability. This study, thus, provides fundamental data and aids in the industrial‐scale implementation of a future hydrogen economy.
Plain Language Summary
Hydrogen is currently assessed as a future clean fuel in a hydrogen economy. However, one key problem with implementing a hydrogen economy is hydrogen storage (as hydrogen is highly compressible and volatile). One solution for this problem is hydrogen geo‐storage, where compressed hydrogen is injected into geological formations; the hydrogen can be withdrawn again at any time. However, there is a serious lack of data from realistic geologic conditions, including hydrogen‐rock wettability, which is a key parameter in this process. We thus, conducted experiments and demonstrate that sandstone is weakly water‐wet to intermediate‐wet. This study, thus, provides fundamental data and aids in the industrial‐scale implementation of a future hydrogen economy.
Key Points
Sandstone reservoirs are weakly water‐wet to intermediate‐wet at expected hydrogen storage depths
Hydrogen wettability increases with pressure and thus depth
Organic molecules on the sandstone surface strongly increase hydrogen wettability
Glycogen storage diseases (GSDs) type I (GSDI) and type III (GSDIII), the most frequent hepatic GSDs, are due to defects in glycogen metabolism, mainly in the liver. In addition to hypoglycemia and ...liver pathology, renal, myeloid, or muscle complications affect GSDI and GSDIII patients. Currently, patient management is based on dietary treatment preventing severe hypoglycemia and increasing the lifespan of patients. However, most of the patients develop long-term pathologies. In the past years, gene therapy for GSDI has generated proof of concept for hepatic GSDs. This resulted in a recent clinical trial of adeno-associated virus (AAV)-based gene replacement for GSDIa. However, the current limitations of AAV-mediated gene transfer still represent a challenge for successful gene therapy in GSDI and GSDIII. Indeed, transgene loss over time was observed in GSDI liver, possibly due to the degeneration of hepatocytes underlying the physiopathology of both GSDI and GSDIII and leading to hepatic tumor development. Moreover, multitissue targeting requires high vector doses to target nonpermissive tissues such as muscle and kidney. Interestingly, recent pharmacological interventions or dietary regimen aiming at the amelioration of the hepatocyte abnormalities before the administration of gene therapy demonstrated improved efficacy in GSDs. In this review, we describe the advances in gene therapy and the limitations to be overcome to achieve efficient and safe gene transfer in GSDs.
Implementation of the hydrogen economy for emission reduction will require storage facilities, and underground hydrogen storage (UHS) in porous media offers a readily available large‐scale option. ...Lack of studies on multiphase hydrogen flow in porous media is one of the several barriers for accurate predictions of UHS. This paper reports, for the first time, measurements of hysteresis in hydrogen‐water relative permeability in a sandstone core under shallow storage conditions. We use the steady state technique to measure primary drainage, imbibition and secondary drainage relative permeabilities, and extend laboratory measurements with numerical history matching and capillary pressure measurements to cover the whole mobile saturation range. We observe that gas and water relative permeabilities show strong hysteresis, and nitrogen as substitute for hydrogen in laboratory assessments should be used with care. Our results serve as calibrated input to field scale numerical modeling of hydrogen injection and withdrawal processes during porous media UHS.
Plain Language Summary
Hydrogen storage facilities will need a ramp‐up when the hydrogen share in the future energy mix increase. Large‐scale hydrogen storage can be implemented in empty hydrocarbon fields or ground water reservoirs. Hydrogen storage in such media involve complex interactions with native rocks and fluids, and injection and withdrawal are typically described by flow functions. Relative permeability is one of the key flow functions that describe how easily hydrogen can flow through porous media in the presence of other fluids. In underground storage, hydrogen is cyclically injected and withdrawn multiple times, and its relative permeability may differ between these two processes, described as hysteresis. In this paper, we investigate hydrogen relative permeability in the laboratory and match with results from numerical simulations. We find that hydrogen relative permeability is different for injection and withdrawal and is also different from that of nitrogen. Our results are directly applicable in computer simulators that predict hydrogen storage efficiency.
Key Points
Steady state measurements of hydrogen‐water relative permeability
Numerical history matching needed for extrapolation
Strong hysteresis observed between drainage and imbibition
Thermal energy storage combined with thermal cycles is an alternative option for storage in electrical power grids. Intermediate storage of electric energy as heat offers advantages such as free ...choice of site, small environmental footprint, life expectancies of 20–30 years and optional low-cost backup capacity. The key element in pumped thermal energy storage (PTES) concepts is the application of a left running thermal cycle to transform low temperature heat into high temperature heat, which is stored in the thermal storage during charging. PTES allows higher storage efficiencies than a direct electric heating of the thermal storage unit. The optional combination of electricity and heat during charging and discharging makes PTES a promising tool for the management of various types of energy in systems with high shares of renewable energy.
CHEST (Compressed Heat Energy STorage) is a specific PTES variant based on Rankine cycles using either water or organic media as the working fluid in combination with latent heat storage units. This paper focuses on the application of CHEST for the management of heat and electricity. Different options for the implementation of CHEST will be presented, for these variants, characteristic values such as operating parameters and power ratio are given and the required components described. The focus is on the technological possibility of using pumped thermal energy storage as a sector-coupling technology for heat and electricity through low temperature heat integration. In addition, new findings of an in-depth numerical simulation of a fully heat-integrated, subcritical PTES using butene as the working fluid are presented.
•A low-temperature Compressed CO2 Energy Storage system was proposed in this paper.•Conventional and advanced exergy analyses on the system were conducted.•The two methods showed that compressor ...should be firstly improved.•Advanced exergy analysis revealed that HEX3 had a higher priority than other HEXs.•The exergy efficiency difference between real and unavoidable conditions was 21.4%.
Compressed Carbon dioxide Energy Storage (CCES) system is a novel energy storage technology, which provides a new method to solve the unstable problem of renewable energy. Since the CCES system using low-temperature thermal energy storage can avoid the technical difficulties from high-temperature thermal energy storage, the low-temperature Compressed Carbon dioxide Energy Storage (LT-CCES) system has more obvious application feasibility compared with the high-temperature energy storage system. As the research on energy conversion, transfer, and loss in CCES system under low-temperature heat storage is still missing, while it is important to understand the energy losses for the further optimization of this kind of system, in this paper, the conventional exergy analysis and advanced exergy analysis were utilized to analyze the thermodynamic characteristics of a LT-CCES system consisting of CO2 Brayton cycle, low-temperature thermal energy storage and cold energy storage, whose thermal energy storage temperature is below 200 °C. As the advanced exergy analysis takes into account the correlation between system components as well as the technical limitations of each component, exergy destruction can be split into more detailed parts (i.e., avoidable exergy destruction, unavoidable exergy destruction, endogenous exergy destruction, and exogenous exergy destruction), which makes the results of the advanced exergy analysis different from those of conventional exergy analysis. The results showed that, advanced exergy analysis pointed out that HEX3 should be given priority as endogenous avoidable exergy destruction in HEX3 was the largest, while the results from the conventional exergy analysis showed that HEX1 should be given priority. For all the components, the two methods indicated that the compressor should be given the highest priority for improvement, followed by the turbine. Besides, as the total exergy efficiency of the system was 55.3% under the real condition and the total exergy efficiency was 76.7% under the unavoidable condition, there was still room for improvement of the system. In brief, based on the advanced exergy analysis method, the real component that should be paid attention can be determined, which gives the designers a more profound understanding of exergy destruction in the LT-CCES system.
Electricity storage (ES) has the potential of offering several energy system benefits but different technologies also offer different services which can be traded on different markets. In this study, ...a combined assessment methodology is proposed, enabling a benchmark comparison of stationary electricity storage technologies for different time and system scales, considering their technical, economic and environmental performance.
The results show that for short time scale (0.01 h), battery stands out with an advantage in terms of levelised costs, while Advanced Adiabatic (AA-) and Isothermal (I-) Compressed Air Energy Storage (CAES) have relatively low life cycle Greenhouse Gas (GHG) emissions. For the medium time scale (4.5 h), I-CAES shows the best performance for small scale systems, while for large scale systems, Pumped Hydro Storage (PHS) and AA-CAES show best performance. In our long time scale (seasonal) scenario, Power-to-gas-to-power (P2G2P) has lower levelised costs due to low or avoided investment for storage of gas, but higher GHG emissions than other technologies. If existing reservoirs can be utilized for PHS, it can be economically competitive to P2G2P for seasonal storage. However, storage capacity required for seasonal storage should also be taken into account, for which P2G2P has more flexibility.
•Stationary electricity storage assessment combining techno-economic and life cycle assessment.•Current and future performance variations, type and price of electricity stored were considered.•Performances of storages were investigated under different time- and system-scales.•Storage technologies perform quite differently based on applications and the electricity stored.•Recommendations were made in terms of preference of technologies for different applications.
PDF
