Effect of Pasteurization and Retort Processing on Spectral Characteristics,Morphological, Thermal,Physico‐Mechanical,Barrier and Optical Properties of Nylon‐Based Food Packaging Materials

The effect of pasteurization and retort processing on spectral, morphological, thermal, physico‐mechanical, barrier and optical properties of three different packaging materials viz., PP/N6/PP, PET/N6/cPP and SiO_x‐PET/N6/cPP were studied. These packaging materials were packed with distilled water, which acted as a food simulant. Subsequently, these pouches were subjected to different thermal processing conditions such as pasteurization and retort processing. Both the processing techniques found to have retained the mechanical properties of all packaging materials. Water vapour transmission rate (WVTR) and oxygen transmission rate (OTR) of nylon‐based combinations were increased after processing. Gloss found to decrease invariably irrespective of the material and increases with the severity of the treatment. XRD diffractogram shows changes in crystal structure as a result of thermal processing, and SEM analysis shows the crystal fragmentation. Absorption of water by the amide group of nylon 6 was observed, which could be a reason for the increase in OTR and WVTR. Copyright © 2014 John Wiley & Sons, Ltd.     

Theoretical analysis of energy-saving performance and economics of CO2 and NH3 heat pumps with simultaneous cooling and heating applications in food processing

Food processing has significant simultaneous requirements of cooling, warm water and hot water. In order to reduce energy consumption and greenhouse gases emission, one type of NH₃ heat pump and two types of transcritical CO₂ heat pumps are proposed. These natural refrigerant heat pumps can supply not only cooling, but also warm water and hot water simultaneously. The characteristics and performance of the heat pumps are analyzed and simulated. Annual primary energy saving and annual operation cost saving are predicted for California, Wisconsin, New York, and Florida. Research results show that the maximum possible value of annual primary energy-saving rates using the CO₂ heat pumps ranges from 56% to 65%, and using the NH₃ heat pump is approximately 44%; the maximum possible value of annual operation cost saving rates using the CO₂ heat pumps ranges from 50% to 66%, and using the NH₃ heat pump is from 20% to 47%.     

重庆市某科研教学楼冰蓄冷空调系统设计与分析

对重庆市某科研教学楼进行冰蓄冷空调系统的设计与分析,并与该科研教学楼现在实际运行的常规空调系统进行经济性比较,分析了初投资、运行费用及投资回收期。和常规空调系统相比,冰蓄冷空调系统多投资约97万元,年运行费节省约16.1万元/a,投资回收期为6a;减少装机容量约40.86%;减少配电量约38.58%。该楼采用商业用电政策比采用居民用电政策节约更多的运行费用（居民用电与商业用电峰谷电价比均为3：1,峰谷电价差分别为0.54元/kWh,0.82元/kWh）,并使投资回收期减少一年。     

A fuzzy logic-controlled thermal process for simultaneous pasteurization and cooking of soft-boiled eggs

A fuzzy logic-based design of control for a unique thermal process in the food industry is presented. Products of the thermal process are pasteurized soft-boiled eggs. The function of temperature vs. time is unique in its shape and in its required precision, since the constraints of pasteurization and cooking of soft-boiled eggs are technically contradictory. Both processes can coexist only in a quite narrow temperature range, which is a nonlinear function of egg processing time. Precision in temperature control is essential. The thermal process is implemented in an apparatus that presents a novelty on the market of industrial kitchen appliances.A precondition for the present work was simulation of thermal energy propagation in hens' eggs of different sizes and ages. A function of temperature vs. time for the media in which eggs are immersed was defined. The function is piecewise linear in time, with horizontal and near vertical sections and abrupt transitions between them.The process is patented and the quality of pasteurization is certified by the corresponding institutes. The result is pasteurized soft-boiled eggs for consumption in hospitals, schools and hotels. The presented fuzzy control implementation of the thermal process meets the requirements, and thus the implication is that the design and implementation of temperature control based on fuzzy logic is suitable for processes where precision is required.     

Promise and potential of air-to-air energy recovery systems

This paper describes and discusses the principles, advantages, and disadvantages of several types of air-to-air energy recovery devices including the open and closed runaround systems, the heat pipe exchanger, the thermal wheel, and the plate exchanger. Emphasis is placed on the potential energy savings in heating and cooling equipment and fuel costs by recovering energy from exhaust air before it is thrown away. Results indicate annual energy savings up to 23% with even larger savings in the size of the heating and cooling equipment. As expected, greatest savings occur when large amounts of outside air are required for ventilation.     

VRV多联机地源热泵系统的技术经济案例分析

VRV多联机地源热泵是由VRV多联机和地源热泵两种技术组合而成的一种新的节能技术.这里以上海某办公楼的VRV多联机地源热泵系统为研究对象,与其他三种常规空调系统进行比较,对VRV多联机地源热泵系统的经济性进行分析.利用BIN法对该办公楼各空调方案的能耗进行计算,并结合上海市的公共事业费率,通过对比分析各方案的一次能耗、初投资、运行费用、费用年值,得到VRV多联机地源热泵系统的经济性.     

啤酒罐装机储液缸内液位控制系统设计

目的为了提高产业中啤酒罐装的质量和效率,精准控制储液罐内液位。方法利用双容水箱建立实验数学模型,在PID串级控制和DMC控制等2种算法下仿真,并进行参数整定,对比分析仿真结果。应用OPC技术实现KingACT和组态王数据通信来设计监控界面。结果 DMC控制汲取PID的快速性和串级控制响应快的特点,使得整体具有响应快、稳定性好和超调量小的特性。监控界面可以实时形象地反映控制过程。结论该控制系统控制性能佳,鲁棒性强,且成本较低,可用来提高啤酒罐装机灌装效率。     

Biosorption of copper and lead ions by waste beer yeast

Locally available waste beer yeast, a byproduct of brewing industry, was found to be a low cost and promising adsorbent for adsorbing copper and lead ions from wastewater. In this work, biosorption of copper and lead ions on waste beer yeast was investigated in batch mode. The equilibrium adsorptive quantity was determined to be a function of the solution pH, contact time, beer yeast concentration, salt concentration and initial concentration of copper and lead ions. The experimental results were fitted well to the Langmuir and Freundlich model isotherms. According to the parameters of Langmuir isotherm, the maximum biosorption capacities of copper and lead ions onto beer yeast were 0.0228 and 0.0277 mmol g(-1) at 293 K, respectively. The negative values of the standard free energy change (DeltaG degrees ) indicate spontaneous nature of the process. Competitive biosorption of two metal ions was investigated in terms of sorption quantity. The amount of one metal ion adsorbed onto unit weight of biosorbent (q(e)) decreased with increasing the competing metal ion concentration. The binding capacity for lead is more than for copper. Ion exchange is probably one of the main mechanism during adsorptive process.     

Superheated steam drying of Brewer’s spent grain in a rotary drum

Relative to conventional air drying, superheated steam (SHS) drying provides a number of benefits such as increased efficiency, reduced risk of fire and explosion, sterilization, deodorization and faster drying rates. Brewer’s spent grain (BSG) is the by-product from beer brewing. It is a sticky material with a tendency to foul drying equipment. This paper evaluates the drying behaviour of BSG in a pilot-scale rotary SHS dryer. The evaluation is based on product moisture content, measurements of sticking and energy consumption.The results of an experimental design for three system parameters (steam temperature, steam velocity and feed rate) are presented for two processing levels. The critical parameters with the most significant effect on the moisture content are the feed rate and the inlet steam temperature. The sticking profile was found to vary exponentially along the drum length. A correlation between sticking and product moisture content was obtained and the operating conditions which minimize sticking were determined.An evaluation of the energy consumption showed that around 70% of the heater energy was used in drying. The remaining energy is lost due to surface losses and cold air ingress.This study has demonstrated that BSG can be dried successfully and efficiently with the proposed technology.     

Battery materials for low-cost electric transportation

This review considers key parameters for affordable Li-ion battery (LIB) – powered electric transportation, such as mineral abundance for active material synthesis, raw materials’ processing cost, cell performance characteristics, cell energy density, and the cost of cell manufacturing. We analyze the scarcity of cobalt (Co) and nickel (Ni) resources available for intercalation-type LIB cathode materials, estimate the demands for these metals by transportation and other industries and discuss risk factors for their price increase within the next two decades. We further contrast performance and estimated costs of LIBs based on intercalation materials, such as lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LFP) and other oxide-based cathodes and carbonaceous anodes, with those of LIBs based on conversion-type active materials, such as lithium sulfide (Li₂S) and lithium fluoride/iron (Fe) and copper (Cu)-based cathodes and silicon (Si)-based anodes. Our analyses of industry data suggest that in the long-term the LIB price will be dominated by cost of the cathode materials. In addition, the cost contributions of manufacturing, overhead and inactive materials will be reversely proportional to the cell energy density. As such, we expect that to-be developed energy-dense conversion-type LIBs should be able to reach the $30–40/kWh by around 2040–2050, while the intercalation-type LIBs will likely be 60% more expensive and sensitive to the Ni price variations. By analyzing the availability and costs of lithium (Li), sulfur (S), Si, fluorine (F), Fe and Cu we conclude that the lower cost, broader accessibility, much greater abundance, and improved health and safety aspects of employing conversion-type chemistries should warrant dedication of substantial efforts in their development. Furthermore, we predict that based on pure economics, the widespread introduction of zero carbon-emission transportation and sustainable energy sources is inevitable and independent on the winning LIB chemistry.     

一种制冷机组能效定量评价方法

在冷水机组比选过程中,通常会优先选择能效高、变工况性能好的产品,但冷水机组的性能对价格的影响,难以定量评价.通过对逐时负荷和气象参数的研究和变工况条件下COP值的计算,得出不同品牌机组年运行费用差异,并折算成价格因素,将机组性能量化,用此方法,可方便不同品牌的冷水机组间进行比选.     

Rigorous optimization of heat-integrated and Petlyuk column distillation configurations based on feed conditions

The steady-state design and rigorous simulation of conventional distillation configurations and several energy-integrated configurations has been studied for ternary mixture separation. The studied configurations are optimized rigorously based on total annual cost as the economic objective function. The energy-integrated distillation configurations are compared with conventional configurations to find the maximum achievable total annual cost savings. Changing feed conditions is considered as one of the optimization variables by investigating different states of feed conditions; feed at 15.5°C temperature, liquid at bubble point and vapor at dew point. The investigated configurations are conventional direct and indirect separation sequence, heat-integrated direct sequences, Petlyuk column, heat-integrated sloppy sequence, and double heat-integrated sloppy sequence. Optimization results indicate that saving in energy and total annual cost of the configurations is affected by the states of the feed conditions.     

Multiphysics design optimization model for structural walls incorporating phase-change materials

The development of energy-efficient building envelopes has been an ongoing effort in many countries owing to the pressing need to achieve energy independence. In this study numerical optimization techniques and finite element analysis provide the means to find a compromise point between adding phase-change materials (PCMs) to a concrete wall, the energy savings and the wall's structural capacity. The primary objective is to minimize the overall lifetime cost of a wall by understanding the implications of PCM layer thickness, material properties and position in the wall on the overall energy consumption. While it is difficult to manually configure a typical wall for the lowest total cost, the developed computational framework provides an automated tool for searching for the best design. The results show that successful designs can be obtained where material and energy costs can be minimized through a judicious combination of existing building materials with thermal energy storage materials.     

Optimisation of a desiccant cooling system design with indirect evaporative cooler

Solar desiccant-based air-conditioning has the potential to significantly reduce cost and/or greenhouse gas emissions associated with cooling of buildings. Parasitic energy consumption for the operation of supply fans has been identified as a major hindrance to achieving these savings. The cooling performance is governed by the trade-off between supplying larger flow-rates of cool air or lower flow-rates of cold air. The performance of a combined solid desiccant-indirect evaporative cooler system is analysed by solving the heat and mass transfer equations for both components simultaneously. Focus is placed on varying the desiccant wheel supply/regeneration and indirect cooler secondary/primary air-flow ratios. Results show that for an ambient reference condition, and 70 °C regeneration temperature, a supply/regeneration flow ratio of 0.67 and an indirect cooler secondary/primary flow ratio of 0.3 gives the best performance with COP_e > 20. The proposed cooling system thus has potential to achieve substantial energy and greenhouse gas emission savings.     

A Flexible Simulation Tool for Manufacturing-cell Design

We present a two-phase approach to design and analysis of manufacturing cells based on simulated experimentation and response surface methodology using a general manufacturing-cell simulation model. The first phase involves factor-screening simulation experiments to identify design and operational factors that have a significant effect on cell performance as measured by a comprehensive annual cost function. In the second phase of experimentation, we construct simulation (response surface) meta-models to describe the relationship between the significant cell design and operational factors (the controllable input parameters) and the resulting simulation-based estimate of expected annual cell cost (the output response). We use canonical and ridge analyses of the estimated response surface to estimate the levels of the quantitative input factors that minimize the cell's expected annual cost. We apply this methodology to an assembly cell for printed circuit boards. Compared to the current cell operating policy, the simulation metamodel-based estimate of the optimum operating policy is predicted to yield average annual savings of approximately $425 000, which is a 20% reduction in annual cost. In a companion paper, we detail the structure and operation of the manufacturing-cell simulation model.     

罐身补涂烘干机能效等级及测试方法研究

本文提出了罐头食品机械中的罐身补涂烘干机能效指标及其测试方法,对罐身补涂烘干机能效测试结果进行了分析,提出了罐身补涂烘干机能效等级划分的建议.     

Energy savings and CO2 emission reduction by using geothermal heat pumps

The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5000 EJ/yr of technical potential; however, its utilization has been limited to areas with special geological conditions. Geothermal heat pumps (GHPs) are one of the fastest growing applications of renewable energy in the world with annual increases of 10% and much faster in China. Its main advantage is that it uses normal ground or groundwater temperatures (between about 5 and 30℃), which are available in all countries of the world and make geothermal more attractive and practicable. With high Coefficient of Performance (COP) up to 6, GHPs make efficiency of primary energy more than 240% with assumed a 40% of electricity generation efficiency, which means energy savings and CO2 emission reduction. In this paper geothermal and GHP technology is introduced and the energy savings and CO2 emission reduction by GHPs are analyzed.     

Energy savings combined with lignin extraction for production increase: case study at a eucalyptus mill in Portugal

In previous research by the authors, energy savings combined with lignin extraction as a means to debottleneck the recovery boiler were evaluated on a model mill. The study showed that this concept was a profitable alternative to recovery boiler upgrade. In the present paper the concept was taken one step further, and the potential for energy savings and possibilities for lignin extraction were evaluated at a real mill: a market pulp mill in Portugal. The energy-saving methods proved to be applicable also to the real mill and the steam-saving potential was 4.2 GJ/ADt or 33%. Lignin extraction trials with bench scale equipment showed that lignin extraction was fully viable at the studied mill. A full-scale lignin separation plant according to the LignoBoost concept, combined with energy savings, was simulated in a computer environment and compared to installation of a new recovery boiler. A new recovery boiler had an investment cost four times higher than the LignoBoost concept combined with energy savings, but the electricity production would be higher. The profitability for a production increase of 16% was calculated for both cases. Steam savings combined with LignoBoost were found to have better profitability unless the electricity price is very high.     

Optimal Selection of Hybrid Renewable Energy System Using Multi-Criteria Decision-Making Algorithms

Several models of multi-criteria decision-making (MCDM) have identified the optimal alternative electrical energy sources to supply certain load in an isolated region in Al-Minya City, Egypt. The load demand consists of water pumping system with a water desalination unit. Various options containing three different power sources: only DG, PV-B system, and hybrid PV-DG-B, two different sizes of reverse osmosis (RO) units; RO-250 and RO-500, two strategies of energy management; load following (LF) and cycle charging (CC), and two sizes of DG; 5 and 10 kW were taken into account. Eight attributes, including operating cost, renewable fraction, initial cost, the cost of energy, excess energy, unmet load, breakeven grid extension distance, and the amount of CO₂, were used during the evaluation process. To estimate these parameters, HOMER^® software was employed to perform both the simulation and optimization process. Four different weight estimation methods were considered; no priority of criteria, based on a pairwise comparisons matrix of the criteria, CRITIC-method, and entropy-based method. The main findings (output results) confirmed that the optimal option for the case study was hybrid PV-DG-B with the following specification: 5 kW DG, RO-500, and load following control strategy. Under this condition, the annual operating cost and initial costs were $ 5546 and $ 161022, respectively, whereas the cost of energy was 0.077 $/kWh. The excess energy and unmet loads were 40998 and 2371 kWh, respectively. The breakeven grid extension distance and the amount of CO₂ were 3.31 km and 5171 kg per year, respectively. Compared with DG only, the amount of CO₂ has been sharply reduced by 113939 kg per year.     

Silicon Migration from High‐barrier Coated Multilayer Polymeric Films to Selected Food Simulants after Microwave Processing Treatments

The use of microwave (MW) technology for in‐package food sterilization and pasteurization has the potential for widespread use in the food industry. Because the use of MW technology requires that food be processed inside its packaging, the interaction between food and its packaging during processing must be studied to ensure package integrity as well as consumer safety. In this study, two commercially available multilayer films developed for retort sterilization were evaluated for their suitability to MW processing. Film A was composed of oriented nylon//coated polyethylene terephthalate//cast polypropylene (CPP); film B consisted of oriented nylon//coated nylon//CPP with overall oxygen transmission rates <0.2 cc/m². day. Silicon (Si) was a major component in the coated polyethylene terephthalate layer and food‐contact CPP layer. This study evaluated the influence of MW processing on Si migration from films into selected food‐simulating liquids (FSLs; water and 3% acetic acid) using inductively coupled plasma‐mass spectroscopy, as compared with conventional thermal processing. This study also assessed migration of Si into FSL in terms of process temperature (70–123 °C) and time (18–34 min). A Fourier transform infrared spectrometer was used to evaluate the stability of the silicon–oxygen (Si–O) bonds in the metal‐oxide coated and food‐contact layer of the packaging film. Overall, there were no significant differences (p > 0.05) between the level of Si migration from films to FSL and the stability of Si–O–Si bonds during MW processing as compared with the conventional thermal processing. However, we found that the final processing temperature and time had a significant (p < 0.05) impact on Si migration into the FSL. Copyright © 2013 John Wiley & Sons, Ltd.