Microgrid Viability for Small-Scale Cooling, Heating, and Power

2006 ◽  
Vol 129 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Lubomir A. Ribarov ◽  
David S. Liscinsky
Keyword(s):  
Net Present Value ◽  
Dimensional Space ◽  
Geographical Location ◽  
Geographic Location ◽  
Electric Heating ◽  
Public Utility ◽  
Environmental Benefits ◽  
Cooling Power ◽  
Small Scale ◽  
Chp System

Cooling, heating, and power (CHP) energy systems provide higher fuel efficiency than conventional systems, resulting in reduced fuel consumption, reduced emissions, and other environmental benefits. Until recently the focus of CHP system development has been primarily on medium-scale commercial applications in a limited number of market segments where clear value propositions lead to short term payback. Small-scale integrated CHP systems that show promise of achieving economic viability through significant improvements in fuel utilization have received increased attention lately. In this paper the economic potential is quantified for small-scale (microgrid) integrated CHP systems suitable for groups of buildings with aggregate electric loads in the 15-120kW range. Technologies are evaluated for community building groups (CBGs) consisting of aggregation of pure residential entities and combined residential and light commercial entities. Emphasis is on determination of the minimum load size (i.e., the smallest electric and thermal load for a given CBG that is supplied with electric, heating, cooling power from a CHP) for which a microgrid CHP system is both technically and economically viable. In this paper, the operation of the CHP system is parallel with the public utility grid at all times, i.e., the grid is interconnected. Evaluations of CHP technology options using simulation studies in a “three-dimensional” space (CHP technology option, CBG load aggregation, and geographical location in the USA) were evaluated based on comparisons of net present value (NPV). The simulations indicated that as electric load increases, the viability of the CHP system (independent of the system’s size) becomes more favorable. Exceeding a system runtime (utilization) of 70% was shown to pass the break-even line in the NPV analysis. Finally, geographic location was found to have a relatively weak effect on the reported trends. These results suggest that microgrid CHP systems have the potential to be economically viable with relative independence of geographic location if adequately sized to match the specific load requirements.

Microgrid Viability for Small-Scale Cooling, Heating, and Power

2005 ◽  
Author(s):  
Lubomir A. Ribarov ◽  
David S. Liscinsky
Keyword(s):  
Net Present Value ◽  
Dimensional Space ◽  
Geographical Location ◽  
Geographic Location ◽  
Public Utility ◽  
Environmental Benefits ◽  
Cooling Power ◽  
Small Scale ◽  
Micro Grid ◽  
Chp System

Cooling, Heating, and Power (CHP) energy systems provide higher fuel efficiency than conventional systems, resulting in reduced emissions and other environmental benefits. Until recently the focus of CHP system development has been primarily on medium-scale commercial applications in a limited number of market segments where clear value propositions lead to short term payback. Small-scale integrated CHP systems that show promise of achieving economic viability through significant improvements in fuel utilization have received increased attention lately. In this paper the economic potential is quantified for small-scale (micro-grid) integrated CHP systems suitable for groups of buildings with aggregate electric loads in the 15 kW–120 kW range. Technologies are evaluated for community building groups (CBGs) consisting of aggregation of pure residential entities and combined residential and light commercial entities. Emphasis is on determination of the minimum load size (i.e. the smallest electric and thermal load for a given CBG that is supplied with electric, heating, cooling power from a CHP) for which a micro-grid CHP system is both technically and economically viable. In this paper, the operation of the CHP system is parallel with the public utility grid at all times, i.e. the grid is interconnected. Evaluations of CHP technology options using simulation studies in a “three-dimensional” space (CHP technology option, CBG load aggregation, and geographical location in the USA) were evaluated based on comparisons of net present value (NPV). The simulations indicated that as electric load increases, the viability of the CHP system (independent of the system’s size) becomes more favorable. Exceeding a system runtime (utilization) of 70% was shown to pass the break-even line in the NPV analysis. Finally, geographic location was found to have a relatively weak effect on the reported trends. These results suggest that micro grid CHP systems have the potential to be economically viable with relative independence of geographic location if adequately sized to match the load requirements.

scholarly journals Assessment of Environmental Impact and Economic Viability of Domestic Biogas Plant Technology in Bangladesh

2021 ◽  
Vol 14 (5) ◽  
pp. 44
Author(s):  
Suraya Akter ◽  
Humayun Kabir ◽  
Shamima Akhter ◽  
Md. Mehedi Hasan
Keyword(s):  
Net Present Value ◽  
Economic Benefits ◽  
Economic Feasibility ◽  
Environmental Benefits ◽  
Economic Viability ◽  
Small Scale ◽  
Cost Ratio ◽  
Cow Dung ◽  
Liquefied Petroleum Gas ◽  
Biogas Technology

The study investigated the distinct environmental impacts and economic viability of domestic biogas technology in the countryside of Bangladesh. The study was carried out by a survey through personal interviews with biogas users. Seventy households were selected purposively and interviews were conducted through semi-structured questionnaires. The study mainly highlighted the potential reduction of greenhouse gas (GHG) emission and economic benefits of biogas utilization which were evaluated considering the substitution of traditional biomass fuels, by saving Liquefied Petroleum Gas (LPG) and cost of chemical fertilizer, and carbon trading. The economic benefits are addressed using some well-known economic indicators like Net Present Value (NPV), Payback Period (PBP), and Benefit-Cost Ratio (BCR). The results of the study revealed that a small-scale household anaerobic cow dung biogas digester not only exhibited the potential to cut carbon emissions on average by about 7.8 tons of CO2 equivalents yearly, but it also demonstrated the economic feasibility of doing so as the value of NPV and BCR was positive. This study recommends that the government approach, awareness program, and continuous and proper performing of the biogas technology are needed to intensify the multiples environmental benefits of the technology.

scholarly journals SPEAR (Solar Pyrolysis Energy Access Reactor): Theoretical Design and Evaluation of a Small-Scale Low-Cost Pyrolysis Unit for Implementation in Rural Communities

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2189
Author(s):  
Cesare Caputo ◽  
Ondřej Mašek
Keyword(s):  
Waste Management ◽  
Rural Areas ◽  
Net Present Value ◽  
Agricultural Waste ◽  
Tracking Error ◽  
Sub Saharan Africa ◽  
Small Scale ◽  
Energy Access ◽  
Efficient System ◽  
Pyrolysis Unit

Energy access and waste management are two of the most pressing developmental and environmental issues on a global level to help mitigate the accelerating impacts of climate change. They are particularly relevant in Sub–Saharan Africa where electrification rates are significantly below global averages and rural areas are lacking a formal waste management sector. This paper explores the potential of integrating solar energy into a biomass pyrolysis unit as a potentially synergetic solution to both issues. The full design of a slow pyrolysis batch reactor targeted at biochar production, following a strict cost minimization approach, is presented in light of the relevant considerations. SPEAR is powered using a Cassegrain optics parabolic dish system, integrated into the reactor via a manual tracking system and optically optimized with a Monte-Carlo ray tracing methodology. The design approach employed has led to the development an overall cost efficient system, with the potential to achieve optical efficiencies up 72% under a 1.5° tracking error. The outputs of the system are biochar and electricity, to be used for soil amendment and energy access purposes, respectively. There is potential to pyrolyze a number of agricultural waste streams for the region, producing at least 5 kg of biochar per unit per day depending on the feedstock employed. Financial assessment of SPEAR yields a positive Net Present Value (NPV) in nearly all scenarios evaluated and a reasonable competitiveness with small scale solar for electrification objectives. Finally, SPEAR presents important positive social and environmental externalities and should be feasibly implementable in the region in the near term.

scholarly journals Simulating Agroforestry Adoption in Rural Indonesia: The Potential of Trees on Farms for Livelihoods and Environment

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 385
Author(s):  
Beatrice Nöldeke ◽  
Etti Winter ◽  
Yves Laumonier ◽  
Trifosa Simamora
Keyword(s):  
Climate Change ◽  
Climate Change Scenario ◽  
Agroforestry System ◽  
Environmental Benefits ◽  
Small Scale ◽  
Change Scenario ◽  
Trees On Farms ◽  
Agroforestry Adoption ◽  
Mitigate Climate Change ◽  
Small Scale Farmers

In recent years, agroforestry has gained increasing attention as an option to simultaneously alleviate poverty, provide ecological benefits, and mitigate climate change. The present study simulates small-scale farmers’ agroforestry adoption decisions to investigate the consequences for livelihoods and the environment over time. To explore the interdependencies between agroforestry adoption, livelihoods, and the environment, an agent-based model adjusted to a case study area in rural Indonesia was implemented. Thereby, the model compares different scenarios, including a climate change scenario. The agroforestry system under investigation consists of an illipe (Shorea stenoptera) rubber (Hevea brasiliensis) mix, which are both locally valued tree species. The simulations reveal that farmers who adopt agroforestry diversify their livelihood portfolio while increasing income. Additionally, the model predicts environmental benefits: enhanced biodiversity and higher carbon sequestration in the landscape. The benefits of agroforestry for livelihoods and nature gain particular importance in the climate change scenario. The results therefore provide policy-makers and practitioners with insights into the dynamic economic and environmental advantages of promoting agroforestry.

Development of Rotary Engine Based Micro-DG/CHP System

2016 ◽  
Author(s):  
Richard L. Hack ◽  
Max R. Venaas ◽  
Vince G. McDonell ◽  
Tod M. Kaneko
Keyword(s):  
Distributed Generation ◽  
Power Output ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Rotary Engine ◽  
Chp System ◽  
Performance Results

Small scale Distributed Generation with waste heat recovery (<50 kW power output, micro-DG/CHP) is an expanding market supporting the widespread deployment of on-site generation to much larger numbers of facilities. The benefits of increased overall thermal efficiency, reduced pollutant emissions, and grid/microgrid support provided by DG/CHP can be maximized with greater quantities of smaller systems that better match the electric and thermal on-site loads. The 3-year CEC funded program to develop a natural gas fueled automotive based rotary engine for micro-DG/CHP, capitalizing upon the unique attributes engine configuration will be presented including initial performance results and plans for the balance of the program.

COMPARATIVE TECHNICAL AND ECONOMIC ESTIMATION OF THE SMALL-SCALE ON-FARM COMPOUND FEED PLANTS

2021 ◽  
pp. 59-65
Author(s):  
SERGEY V. BRAGINETS ◽  
Keyword(s):  
Net Present Value ◽  
Raw Materials ◽  
Farm Animals ◽  
Small Scale ◽  
Hammer Mill ◽  
Capital Investments ◽  
Agricultural Enterprises ◽  
Feed Production ◽  
Effi Ciency ◽  
On Farm

On-farm compound feed production from self-produced raw materials is favorable to agricultural enterprises under present-day conditions. The authors carried out a comparative technical and economic study of the conventional and modular small-scale on-farm compound feed plants with a capacity of 2 tons per hour, designed for agricultural enterprises with an average livestock population of 6…8 thousand pigs. The proposed modular plant consists of two modules – the operative storage of raw materials and the main module of grinding and mixing. Modules with installed equipment are delivered and placed on a light foundation, connected by transport equipment and with tanks for raw materials and fi nished products. The conventional factory is a technological line housed in a hangar and used for crushing, metering, and mixing raw materials. It consists of a separator, a hammer mill, weighing equipment, a mixer, containers for raw materials and fi nished products, transport, and aspiration equipment. The technical and economic analysis has shown that the erection and operation of the on-farm modular enterprise require 41% less capital investments than a traditional compound feed plant of the same capacity. The use of a small-scale modular plant will reduce operating costs by 23.8% (from 3094 to 2358 thousand rubles), increase the specifi c economic eff ect from the compound feed production by 1.6% (from 8.64 to 8.78 thousand rubles per ton) and return on margin by 4% (from 10.2 to 10.6%), reduce the payback period by 42% (from 0.8 to 0.46 years), and increase the net present value by 3% (from 66167 to 68216 thousand rubles), as compared to a conventional enterprise. The modular on-farm plants producing loose compound feed with a productivity of up to 3 tons per hour are profi table and economically sound as they can increase production effi ciency of compound feeds for farm animals.`

Large- and small-scale vortical motions in a shear layer perturbed by tabs

1999 ◽  
Vol 382 ◽  
pp. 307-329 ◽  
Author(s):  
JUDITH K. FOSS ◽  
K. B. M. Q. ZAMAN
Keyword(s):  
Shear Layer ◽  
Pitch Angle ◽  
Large Scale ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Small Scale ◽  
Streamwise Vortices ◽  
Streamwise Vorticity ◽  
Cross Sectional ◽  
Scale Population

The large- and small-scale vortical motions produced by ‘delta tabs’ in a two-stream shear layer have been studied experimentally. An increase in mixing was observed when the base of the triangular shaped tab was affixed to the trailing edge of the splitter plate and the apex was pitched at some angle with respect to the flow axis. Such an arrangement produced a pair of counter-rotating streamwise vortices. Hot-wire measurements detailed the velocity, time-averaged vorticity (Ωx) and small-scale turbulence features in the three-dimensional space downstream of the tabs. The small-scale structures, whose scale corresponds to that of the peak in the dissipation spectrum, were identified and counted using the peak-valley-counting technique. The optimal pitch angle, θ, for a single tab and the optimal spanwise spacing, S, for a multiple tab array were identified. Since the goal was to increase mixing, the optimal tab configuration was determined from two properties of the flow field: (i) the large-scale motions with the maximum Ωx, and (ii) the largest number of small-scale motions in a given time period. The peak streamwise vorticity magnitude [mid ]Ωx−max[mid ] was found to have a unique relationship with the tab pitch angle. Furthermore, for all cases examined, the overall small-scale population was found to correlate directly with [mid ]Ωx−max[mid ]. Both quantities peaked at θ≈±45°. It is interesting to note that the peak magnitude of the corresponding circulation in the cross-sectional plane occurred for θ≈±90°. For an array of tabs, the two quantities also depended on the tab spacing. An array of contiguous tabs acted as a solid deflector producing the weakest streamwise vortices and the least small-scale population. For the measurement range covered, the optimal spacing was found to be S≈1.5 tab widths.

scholarly journals Optimal Ways of Unloading and Loading Operations under Arctic Conditions

2021 ◽  
Vol 9 (10) ◽  
pp. 1050
Author(s):  
Marat Eseev ◽  
Dmitry Makarov
Keyword(s):  
Mathematical Modeling ◽  
Geographical Location ◽  
Geographic Location ◽  
Economic Benefits ◽  
Transport Infrastructure ◽  
The Arctic ◽  
Cargo Delivery ◽  
Arctic Conditions ◽  
Loading And Unloading ◽  
The Right

Usually, loading and unloading of cargo ships takes place in ports that are equipped with the infrastructure necessary to carry out such operations. In the Arctic, often a helicopter is the only way to get the cargo to the right place. Finding the optimal geographic location for unloading a ship using helicopters is an important task. It is necessary to create a support system for making the right decisions in such situations. Mathematical modeling has been used to find the geographical location that ensures the most favorable and quickest delivery of cargo from a vessel to its destination, using a helicopter. A criterion has also been found in which the search for the optimum point is a more rational way of unloading the vessel compared to other discharge options. The maps of the economic benefits of loading and unloading operations in this model have been developed. Using the example of the developed model, it is shown that during the transportation of goods in Ob Bay, significant economic and temporary advantages can be obtained. The developed model can be extended to the case of cargo delivery not only in the Arctic conditions, but also where the transport infrastructure is insufficiently developed.

scholarly journals Goldilocks mixing in oceanic shear-induced turbulent overturns

2021 ◽  
Vol 928 ◽  
Author(s):  
A. Mashayek ◽  
C.P. Caulfield ◽  
M.H. Alford
Keyword(s):  
Ocean Circulation ◽  
Turbulent Mixing ◽  
Intermediate Phase ◽  
Turbulent Flux ◽  
Geographical Location ◽  
Small Scale ◽  
Supporting Evidence ◽  
Stratified Turbulence ◽  
Wide Range ◽  
Variable Flux

We present a new, simple and physically motivated parameterization, based on the ratio of Thorpe and Ozmidov scales, for the irreversible turbulent flux coefficient $\varGamma _{\mathcal {M}}= {\mathcal {M}}/\epsilon$ , i.e. the ratio of the irreversible rate ${\mathcal {M}}$ at which the background potential energy increases in a stratified flow due to macroscopic motions to the dissipation rate of turbulent kinetic energy $\epsilon$ . Our parameterization covers all three key phases (crucially, in time) of a shear-induced stratified turbulence life cycle: the initial, ‘hot’ growing phase, the intermediate energetically forced phase and the final ‘cold’ fossilization decaying phase. Covering all three phases allows us to highlight the importance of the intermediate one, to which we refer as the ‘Goldilocks’ phase due to its apparently optimal (and so neither too hot nor too cold, but just right) balance, in which energy transfer from background shear to the turbulent mixing is most efficient. The value of $\varGamma _{\mathcal {M}}$ is close to 1/3 during this phase, which we demonstrate appears to be related to an adjustment towards a critical or marginal Richardson number for sustained turbulence ${\sim }0.2\text {--}0.25$ . Importantly, although buoyancy effects are still significant at leading order for the turbulent dynamics during this intermediate phase, the marginal balance in the flow ensures that the turbulent mixing of the (density) scalar is nevertheless effectively ‘locked’ to the turbulent mixing of momentum. We present supporting evidence for our parameterization through comparison with six oceanographic datasets that span various turbulence generation regimes and a wide range of geographical location and depth. Using these observations, we highlight the significance of parameterizing an inherently variable flux coefficient for capturing the turbulent flux associated with rare energetic, yet fundamentally shear-driven (and so not strongly stratified) overturns that make a disproportionate contribution to the total mixing. We also highlight the importance of representation of young turbulent patches in the parameterization for connecting the small scale physics to larger scale applications of mixing such as ocean circulation and tracer budgets. Shear-induced turbulence is therefore central to irreversible mixing in the world's oceans, apparently even close to the seafloor, and it is critically important to appreciate the inherent time dependence and evolution of mixing events: history matters to mixing.

scholarly journals Elongated Gravity Sources as an Analytical Limit for Flat Galaxy Rotation Curves

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 346
Author(s):  
Felipe J. Llanes-Estrada
Keyword(s):  
Galactic Plane ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Small Scale ◽  
Scaling Exponent ◽  
Rotation Curves ◽  
Central Mass ◽  
Filamentary Structure ◽  
Analytical Limit ◽  
Galaxy Rotation Curves

The flattening of spiral-galaxy rotation curves is unnatural in view of the expectations from Kepler’s third law and a central mass. It is interesting, however, that the radius-independence velocity is what one expects in one less dimension. In our three-dimensional space, the rotation curve is natural if, outside the galaxy’s center, the gravitational potential corresponds to that of a very prolate ellipsoid, filament, string, or otherwise cylindrical structure perpendicular to the galactic plane. While there is observational evidence (and numerical simulations) for filamentary structure at large scales, this has not been discussed at scales commensurable with galactic sizes. If, nevertheless, the hypothesis is tentatively adopted, the scaling exponent of the baryonic Tully–Fisher relation due to accretion of visible matter by the halo comes out to reasonably be 4. At a minimum, this analytical limit would suggest that simulations yielding prolate haloes would provide a better overall fit to small-scale galaxy data.

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