scholarly journals The potential of coffee stems  gasification to provide bioenergy for coffee farms: a case study in the Colombian coffee sector

2019 ◽  
Vol 10 (4) ◽  
pp. 1137-1152 ◽  
Author(s):  
Samira Garcia-Freites ◽  
Andrew Welfle ◽  
Amanda Lea-Langton ◽  
Paul Gilbert ◽  
Patricia Thornley
Keyword(s):  
Rural Areas ◽  
Internal Combustion Engines ◽  
Smallholder Farmers ◽  
Thermochemical Conversion ◽  
Small Scale ◽  
Low Grade ◽  
Coffee Production ◽  
Coffee Sector ◽  
Low Grade Heat

AbstractThe coffee industry constitutes an important part of the global economy. Developing countries produce over 90% of world coffee production, generating incomes for around 25 million smallholder farmers. The scale of this industry poses a challenge with the generation of residues along with the coffee cultivation and processing chain. Coffee stems, obtained after pruning of coffee trees, are one of those abundant and untapped resources in the coffee supply chain. Their high lignocellulosic content, the low calorific value ranging between 17.5 and 18 MJ kg−1 and the low ash content make them a suitable solid fuel for thermochemical conversion, such as gasification. This research evaluates the feasibility of using these residues in small-scale downdraft gasifiers coupled to internal combustion engines for power and low-grade heat generation, using process modelling and the Colombian coffee sector as a case study. The producer gas properties (5.6 MJ Nm−3) and the gasifier’s performance characteristics suggest that this gas could be utilized for power generation. A cogeneration system efficiency of 45.6% could be attainable when the system’s low-grade heat is recovered for external applications, like in the coffee drying stage. An analysis of the energy demand and coffee stems availability within the Colombian coffee sector shows that the biomass production level in medium- to large-scale coffee farms is well matched to their energy demands, offering particularly attractive opportunities to deploy this bioenergy system. This work assesses the feasibility of providing coffee stem–sourced low-carbon energy for global coffee production at relevant operating scales in rural areas.

scholarly journals Small Scale Power Generation using Low Grade Heat from Solar Pond

2012 ◽  
Vol 49 ◽  
pp. 50-56 ◽  
Author(s):  
Baljit Singh ◽  
J. Gomes ◽  
Lippong Tan ◽  
Abhijit Date ◽  
A. Akbarzadeh
Keyword(s):  
Power Generation ◽  
Small Scale ◽  
Low Grade ◽  
Solar Pond ◽  
Low Grade Heat

Complex Energy Networks Optimization: Part II — Software Application to a Case Study

2020 ◽  
Author(s):  
M. A. Ancona ◽  
M. Bianchi ◽  
L. Branchini ◽  
A. De Pascale ◽  
F. Melino ◽  
...  
Keyword(s):  
Energy Production ◽  
Internal Combustion Engines ◽  
Energy Systems ◽  
Distribution Networks ◽  
Optimal Scheduling ◽  
Small Scale ◽  
Complex Energy ◽  
Energy Networks ◽  
Energy Network

Abstract In order to increase the exploitation of the renewable energy sources, the diffusion of the distributed generation systems is grown, leading to an increase in the complexity of the electrical, thermal, cooling and fuel energy distribution networks. With the main purpose of improving the overall energy conversion efficiency and reducing the greenhouse gas emissions associated to fossil fuel based production systems, the design and the management of these complex energy grids play a key role. In this context, an in-house developed software, called COMBO, presented and validated in the Part I of this study, has been applied to a case study in order to define the optimal scheduling of each generation system connected to a complex energy network. The software is based on a non-heuristic technique which considers all the possible combination of solutions, elaborating the optimal scheduling for each energy system by minimizing an objective function based on the evaluation of the total energy production cost and energy systems environmental impact. In particular, the software COMBO is applied to a case study represented by an existing small-scale complex energy network, with the main objective of optimizing the energy production mix and the complex energy networks yearly operation depending on the energy demand of the users. The electrical, thermal and cooling needs of the users are satisfied with a centralized energy production, by means of internal combustion engines, natural gas boilers, heat pumps, compression and absorption chillers. The optimal energy systems operation evaluated by the software COMBO will be compared to a Reference Case, representative of the current energy systems set-up, in order to highlight the environmental and economic benefits achievable with the proposed strategy.

scholarly journals The contribution of small-scale rural irrigation schemes towards food security of smallholder farmers in Zimbabwe

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Smart Mhembwe ◽  
Newman Chiunya ◽  
Ernest Dube
Keyword(s):  
Food Security ◽  
Rural Areas ◽  
Smallholder Farmers ◽  
Small Scale ◽  
Security Challenges ◽  
The Status ◽  
Midlands Province ◽  
Observation Method ◽  
Effective Use ◽  
Small Scale Irrigation

Smallholder farmers across Zimbabwe have been facing a problem of food insecurity because of climate-induced droughts and lack of effective use of irrigation schemes. Rainfall patterns in the country have become more unpredictable and inconsistent with the traditional farming seasons. Faced with such challenges, many smallholder farmers in Shurugwi district in the Midlands province of Zimbabwe adopted small-scale irrigation schemes to improve food security. The principal objectives of this study were to examine the status of the irrigation schemes in the district; analyse the need to rehabilitate small-scale irrigation schemes; assess the initiatives towards the revival of irrigation schemes; establish the benefits that can accrue to smallholder farmers from small-scale irrigation schemes and discuss challenges faced by smallholder farmers in the running of small-scale irrigation schemes in rural areas. This qualitative study employed literature and interviews to obtain data from 40 purposively selected participants. The direct observation method was used to compliment the interviews. The findings of the study were that small-scale rural irrigation schemes have the capacity to significantly transform the lives of rural farmers through earning increased reliable income from farming if institutional and capacity issues of the farmers are addressed. Furthermore, the study found that small-scale irrigation schemes can also be a panacea to food security challenges mainly faced by rural households. As such, the article concluded that irrigation schemes are fortress and antidote to the effects of climate change. The study calls for capacity promotion on technical skills for the farmers, the establishment of many new irrigation schemes and the rehabilitation of the existing small-scale irrigation schemes in the country as well as calling on the farmers to adopt climate-smart irrigation.

Thermo-economic optimization of small-scale Organic Rankine Cycle: A case study for low-grade industrial waste heat recovery

Energy ◽  
2020 ◽  
Vol 213 ◽  
pp. 118898
Author(s):  
Bernardo Peris ◽  
Joaquín Navarro-Esbrí ◽  
Carlos Mateu-Royo ◽  
Adrián Mota-Babiloni ◽  
Francisco Molés ◽  
...  
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Small Scale ◽  
Low Grade ◽  
Economic Optimization ◽  
Industrial Waste Heat

scholarly journals Heat Based Power Augmentation for Modular Pumped Hydro Storage in Smart Buildings Operation

2021 ◽  
Author(s):  
Yang Chen ◽  
Ahmad Abu-Heiba ◽  
Saiid Kassaee ◽  
Chenang Liu ◽  
Guodong Liu ◽  
...  
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Ground Level ◽  
Small Scale ◽  
Low Grade ◽  
Discharge Process ◽  
Gas Temperature ◽  
Oak Ridge ◽  
Storage Technology ◽  
Low Grade Heat

Abstract In the U.S., building sector is responsible for around 40% of total energy consumption and contributes about 40% of carbon emissions since 2012. Within the past several years, various optimization models and control strategies have been studied to improve buildings energy efficiency and reduce operational expenses under the constraints of satisfying occupants’ comfort requirements. However, the majority of these studies consider building electricity demand and thermal load being satisfied by unidirectional electricity flow from the power grid or on-site renewable energy generation to electrical and thermal home appliances. Opportunities for leveraging low grade heat for electricity have largely been overlooked due to impracticality at small scale. In 2016, a modular pumped hydro storage technology was invented in Oak Ridge National Laboratory, named Ground Level Integrated Diverse Energy Storage (GLIDES). In GLIDES, employing high efficiency hydraulic machinery instead of gas compressor/turbine, liquid is pumped to compress gas inside high-pressure vessel creating head on ground-level. This unique design eliminates the geographical limitation associated with existing state of the art energy storage technologies. It is easy to be scaled for building level, community level and grid level applications. Using this novel hydro-pneumatic storage technology, opportunities for leveraging low-grade heat in building can be economical. In this research, the potential of utilizing low-grade thermal energy to augment electricity generation of GLIDES is investigated. Since GLIDES relies on gas expansion in the discharge process and the gas temperature drops during this non-isothermal process, available thermal energy, e.g. from thermal storage, Combined Cooling, Heat and Power system (CCHP), can be utilized by GLIDES to counter the cooling effect of the expansion process and elevate the gas temperature and pressure and boost the roundtrip efficiency. Several groups of comparison experiments have been conducted and the experimental results show that a maximum 12.9% cost saving could be achieved with unlimited heat source for GLIDES, and a moderate 3.8% cost improvement can be expected when operated coordinately with CCHP and thermal energy storage in a smart building.

Sign in / Sign up

Export Citation Format

Share Document