Efficiencies of use of the metabolisable energy from feeds based on barley or sugar beet feed in immature sheep

1989 ◽  
Vol 1989 ◽  
pp. 60-60 ◽  
Author(s):  
G.C. Emmans ◽  
M.R. Cropper ◽  
W.S. Dingwall ◽  
H. Brown ◽  
J D Oldham ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Energy Systems ◽  
Quantitative Relationship ◽  
Energy System ◽  
Single Dimension ◽  
Energy Retention ◽  
Gross Energy ◽  
Metabolisable Energy

The ARC (1980) energy system sees growth in the single dimension of energy retention (ER) which increases, with diminishing marginal efficiency, as ME intake increases. The quantitative relationship between ME intake and ER is predicted from q, the proportion of the gross energy which is metabolisable. An experiment on growing sheep on controlled feeding of different feeds was carried out to provide data suitable for testing ARC (1980) and other energy systems.Scottish Blackface wether sheep in single pens, entered the experiment at 25 kg liveweight (LW), when 11 were slaughtered. The remainder were allocated to 3 x 3 x 3 treatments with an intended 4 replicates per treatment. The factors were (i) feeds: feeds B, U and M shown in Table 1, (ii) levels of feeding. L, M and H where H was 936 g/d at 25 kg and was increased by 52 g/d each week, L was half H and M half-way between L and H, (iii) slaughter point, after 9 or 18 weeks, or at 40 kg liveweight.

An additive and linear general energy scale

1984 ◽  
Vol 1984 ◽  
pp. 70-70
Author(s):  
G.C. Emmans
Keyword(s):  
Heat Production ◽  
Energy Scale ◽  
Positive Energy ◽  
General Energy ◽  
Heat Increment ◽  
Energy Retention ◽  
Gross Energy ◽  
Metabolisable Energy ◽  
General Method ◽  
Fasting Heat Production

Armsby (1903) coined the term metabolisable energy, ME, for the gross energy of a diet less the energy in the faeces, urine and methane apparently produced from it. He stated an animal's requirement for ME as the sum of its fasting heat production, FHP, its positive energy retention, ER, and the heat increment, HI. In this paper a general method for predicting HI is proposed and tested.

Validation of the UK metabolisable energy system and other energy systems

2000 ◽  
Vol 2000 ◽  
pp. 95-95
Author(s):  
T. Yan ◽  
R. E. Agnew
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Energy Systems ◽  
Energy System ◽  
Net Energy ◽  
Calorimetric Data ◽  
Lactating Dairy Cows ◽  
The World ◽  
Metabolisable Energy ◽  
The Uk

The UK metabolisable energy (ME) system for dairy cattle and net energy (NE) systems presently used in Europe and America were developed over 30 years ago. Recent studies have however indicated that these systems could under-predict the ME (MEm) or NE (NEm) requirement for maintenance for current dairy cows (e.g., Yan et al., 1997). The objective of the present study was to validate these systems using calorimetric data produced with lactating dairy cows and published around the world since 1976.

scholarly journals Dynamic Modelling of LNG Powered Combined Energy Systems in Port Areas

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3640
Author(s):  
Davide Borelli ◽  
Francesco Devia ◽  
Corrado Schenone ◽  
Federico Silenzi ◽  
Luca A. Tagliafico
Keyword(s):  
Energy Savings ◽  
Ghg Emissions ◽  
Dynamic Modelling ◽  
Energy Systems ◽  
Energy System ◽  
Primary Energy ◽  
Time Behavior ◽  
Vapor Compression Refrigeration Cycle ◽  
Integrated Energy System ◽  
Energy Share

Liquefied Natural Gas (LNG) is a crucial resource to reduce the environmental impact of fossil-fueled vehicles, especially with regards to maritime transport, where LNG is increasingly used for ship bunkering. The present paper gives insights on how the installation of LNG tanks inside harbors can be capitalized to increase the energy efficiency of port cities and reduce GHG emissions. To this purpose, a novel integrated energy system is introduced. The Boil Off Gas (BOG) from LNG tanks is exploited in a combined plant, where heat and power are produced by a regenerated gas turbine cycle; at the same time, cold exergy from LNG regasification contributes to an increase in the efficiency of a vapor compression refrigeration cycle. In the paper, the integrated energy system is simulated by means of dynamic modeling under daily variable working conditions. Results confirm that the model is stable and able to determine the time behavior of the integrated plant. Energy saving is evaluated, and daily trends of key thermophysical parameters are reported and discussed. The analysis of thermal recovering from the flue gases shows that it is possible to recover a large energy share from the turbine exhausts. Hence, the system can generate electricity for port cold ironing and, through a secondary brine loop, cold exergy for a refrigeration plant. Overall, the proposed solution allows primary energy savings up to 22% when compared with equivalent standard technologies with the same final user needs. The exploitation of an LNG regasification process through smart integration of energy systems and implementation of efficient energy grids can contribute to greener energy management in harbors.

scholarly journals Accessibility and Sustainability of Hybrid Energy Systems for a Cement Factory in Oman

2020 ◽  
Vol 13 (1) ◽  
pp. 93
Author(s):  
Wesam H. Beitelmal ◽  
Paul C. Okonkwo ◽  
Fadhil Al Housni ◽  
Wael Alruqi ◽  
Omar Alruwaythi
Keyword(s):  
Functional Limitations ◽  
Energy Systems ◽  
Energy System ◽  
Electricity Production ◽  
Diesel Generator ◽  
Hybrid Energy ◽  
Electric System ◽  
Cement Factory ◽  
Hybrid Energy Systems ◽  
Cost Of Energy

Diesel generators are being used as a source of electricity in different parts of the world. Because of the significant expense in diesels cost and the requirement for a greener domain, such electric generating systems appear not to be efficient and environmentally friendly and should be tended to. This paper explores the attainability of utilizing a sustainable power source based on a cross-breed electric system in the cement factory in Salalah, Oman. The HOMER software that breaks down the system setup was utilized to examine the application and functional limitations of each hybridized plan. The result showed that a renewable-energy (RE)-based system has a lower cost of energy (COE) and net present cost (NPC) compared to diesel generator-based hybrid electric and standalone systems. Although the two pure renewable hybrid energy systems considered in this study displayed evidence of no emissions, lower NPC and COE values are observed in the photovoltaic/battery (PV/B) hybrid energy system compared with photovoltaic/wind turbine/battery (PV/WT/B). The PV/WT/B and PV/B systems have higher electricity production and low NPC and COE values. Moreover, the PV/B has the highest return on investment (ROI) and internal rate of return (IRR), making the system the most economically viable and adjudged to be a better candidate for rural community electrification demands.

Developing an Integrated Energy System Interface for Electricity-Hydrogen Hybrid Nuclear Operations

2020 ◽  
Vol 64 (1) ◽  
pp. 92-96
Author(s):  
Thomas A. Ulrich ◽  
Roger Lew ◽  
Ronald L. Boring ◽  
Torrey Mortenson ◽  
Jooyoung Park ◽  
...  
Keyword(s):  
Human Factors ◽  
Electricity Markets ◽  
Nuclear Power ◽  
Power Plants ◽  
Energy Systems ◽  
Energy System ◽  
Human Factors Engineering ◽  
Engineering Project ◽  
Early Integration ◽  
Integrated Energy Systems

Nuclear power plants are looking towards integrated energy systems to address the challenges faced by increasing competition from renewable energy and cheap natural gas in wholesale electricity markets. Electricity-hydrogen hybrid operations is one potential technology being explored. As part of this investigation a human factors team was integrated into the overall engineering project to develop a human system interface (HSI) for a novel system to extract steam for a coupled hydrogen production process. This paper presents the process used to perform the nuclear specific human factors engineering required to develop the HSI for this novel and unprecedented system. Furthermore, the early integration of the human factors team and the meaningful improvements to the engineering of the system itself in addition to the successful development of the HSI for this particular application are described. Lastly, the HSI developed is presented to demonstrate the culmination of the process and disseminate a potential HSI design for electricity-hydrogen hybrid operations that may be useful for others exploring similar integrated energy systems concepts.

scholarly journals Dynamic Stability Enhancement of a Hybrid Renewable Energy System in Stand-Alone Applications

Computation ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 14
Author(s):  
Ezzeddine Touti ◽  
Hossem Zayed ◽  
Remus Pusca ◽  
Raphael Romary
Keyword(s):  
Renewable Energy ◽  
Energy Systems ◽  
Experimental Tests ◽  
Energy System ◽  
Induction Generator ◽  
Technical Solution ◽  
Hybrid Energy ◽  
Wind Speeds ◽  
Hybrid Renewable Energy System ◽  
Stability Enhancement

Renewable energy systems have been extensively developed and they are attractive to become widespread in the future because they can deliver energy at a competitive price and generally do not cause environmental pollution. However, stand-alone energy systems may not be practical for satisfying the electric load demands, especially in places having unsteady wind speeds with high unpredictability. Hybrid energy systems seem to be a more economically feasible alternative to satisfy the energy demands of several isolated clients worldwide. The combination of these systems makes it possible to guarantee the power stability, efficiency, and reliability. The aim of this paper is to present a comprehensive analysis and to propose a technical solution to integrate a self-excited induction generator in a low power multisource system. Therefore, to avoid the voltage collapsing and the machine demagnetization, the various parameters have to be identified. This procedure allows for the limitation of a safe operating area where the best stability of the machine can be obtained. Hence, the load variation interval is determined. An improvement of the induction generator stability will be analyzed. Simulation results will be validated through experimental tests.

scholarly journals A Method for Optimizing and Spatially Distributing Heating Systems by Coupling an Urban Energy Simulation Platform and an Energy System Model

Resources ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 52
Author(s):  
Annette Steingrube ◽  
Keyu Bao ◽  
Stefan Wieland ◽  
Andrés Lalama ◽  
Pithon M. Kabiro ◽  
...  
Keyword(s):  
District Heating ◽  
Energy Systems ◽  
Energy System ◽  
Heat Pumps ◽  
Energy Simulation ◽  
Heating Systems ◽  
Optimal Amount ◽  
Urban City ◽  
Urban Energy ◽  
Building Level

District heating is seen as an important concept to decarbonize heating systems and meet climate mitigation goals. However, the decision related to where central heating is most viable is dependent on many different aspects, like heating densities or current heating structures. An urban energy simulation platform based on 3D building objects can improve the accuracy of energy demand calculation on building level, but lacks a system perspective. Energy system models help to find economically optimal solutions for entire energy systems, including the optimal amount of centrally supplied heat, but do not usually provide information on building level. Coupling both methods through a novel heating grid disaggregation algorithm, we propose a framework that does three things simultaneously: optimize energy systems that can comprise all demand sectors as well as sector coupling, assess the role of centralized heating in such optimized energy systems, and determine the layouts of supplying district heating grids with a spatial resolution on the street level. The algorithm is tested on two case studies; one, an urban city quarter, and the other, a rural town. In the urban city quarter, district heating is economically feasible in all scenarios. Using heat pumps in addition to CHPs increases the optimal amount of centrally supplied heat. In the rural quarter, central heat pumps guarantee the feasibility of district heating, while standalone CHPs are more expensive than decentral heating technologies.

scholarly journals Calculation and Analysis of the Interval Power Flow for Distributed Energy System Based on Affine Algorithm

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 600
Author(s):  
Bin Ouyang ◽  
Lu Qu ◽  
Qiyang Liu ◽  
Baoye Tian ◽  
Zhichang Yuan ◽  
...  
Keyword(s):  
Power Flow ◽  
Load Condition ◽  
Energy Systems ◽  
Energy System ◽  
Optimal Operation ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Distributed Energy ◽  
Low Load ◽  
Distributed Energy System

Due to the coupling of different energy systems, optimization of different energy complementarities, and the realization of the highest overall energy utilization rate and environmental friendliness of the energy system, distributed energy system has become an important way to build a clean and low-carbon energy system. However, the complex topological structure of the system and too many coupling devices bring more uncertain factors to the system which the calculation of the interval power flow of distributed energy system becomes the key problem to be solved urgently. Affine power flow calculation is considered as an important solution to solve uncertain steady power flow problems. In this paper, the distributed energy system coupled with cold, heat, and electricity is taken as the research object, the influence of different uncertain factors such as photovoltaic and wind power output is comprehensively considered, and affine algorithm is adopted to calculate the system power flow of the distributed energy system under high and low load conditions. The results show that the system has larger operating space, more stable bus voltage and more flexible pipeline flow under low load condition than under high load condition. The calculation results of the interval power flow of distributed energy systems can provide theoretical basis and data support for the stability analysis and optimal operation of distributed energy systems.

scholarly journals Effect of the Foresight Horizon on Computation Time and Results Using a Regional Energy Systems Optimization Model

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 495
Author(s):  
Jessica Thomsen ◽  
Noha Saad Hussein ◽  
Arnold Dolderer ◽  
Christoph Kost
Keyword(s):  
Computation Time ◽  
Energy Systems ◽  
Energy System ◽  
Variable Cost ◽  
Optimization Approach ◽  
Or Efficiency ◽  
Electricity Grid ◽  
Regional Energy ◽  
Long Run ◽  
Regional Energy Systems

Due to the high complexity of detailed sector-coupling models, a perfect foresight optimization approach reaches complexity levels that either requires a reduction of covered time-steps or very long run-times. To mitigate these issues, a myopic approach with limited foresight can be used. This paper examines the influence of the foresight horizon on local energy systems using the model DISTRICT. DISTRICT is characterized by its intersectoral approach to a regionally bound energy system with a connection to the superior electricity grid level. It is shown that with the advantage of a significantly reduced run-time, a limited foresight yields fairly similar results when the input parameters show a stable development. With unexpected, shock-like events, limited foresight shows more realistic results since it cannot foresee the sudden parameter changes. In general, the limited foresight approach tends to invest into generation technologies with low variable cost and avoids investing into demand reduction or efficiency with high upfront costs as it cannot compute the benefits over the time span necessary for full cost recovery. These aspects should be considered when choosing the foresight horizon.

The estimation of the nutritive value of feeds as energy sources for ruminants and the derivation of feeding systems

1978 ◽  
Vol 90 (1) ◽  
pp. 47-68 ◽  
Author(s):  
K. L. Blaxter ◽  
A. W. Boyne
Keyword(s):  
Organic Matter ◽  
Nutritive Value ◽  
Metabolizable Energy ◽  
Crude Fibre ◽  
Mitscherlich Equation ◽  
Energy Retention ◽  
Gross Energy ◽  
Biological Concepts ◽  
Two Parameters ◽  
Feeding Systems

SUMMARYThe results of 80 calorimetric experiments with sheep and cattle, mostly conducted in Scotland, were analysed using a generalization of the Mitscherlich equation R = B(l–exp(–pG))–l, where R is daily energy retention and G daily gross energy intake, both scaled by dividing by the fasting metabolism. The relations between gross energy and metabolizable energy were also examined. Methods of fitting the Mitscherlich equation and the errors associated with it are presented.It is shown that the gross energy of the organic matter of feed can be estimated from proximate principles with an error of ±2·3% (coefficient of variation) and that provided different classes of feed are distinguished, the metabolizable energy of organic matter can be estimated from gross energy and crude fibre content with an error of ±6·9%. Parameters of the primary equation made with cattle agreed with those made with sheep and there was no evidence of non-proportionality of responses on substitution of feeds in mixtures.The efficiency of utilization of gross energy for maintenance and for body gain of energy was related to the metabolizability of gross energy and, in addition, to fibre or to protein content. Prediction equations are presented which describe these relationships.It is shown that the primary equation can be manipulated to express a number of biological concepts and that its two parameters B and p can be simply derived from estimates of the two efficiency terms for maintenance and production.The results are discussed in relation to the design of feeding systems for ruminant animals and to the derivation of optima in their feeding.

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