Agriculture—Things That Are Grown

Author(s):  
Peter Rez

Timber has the lowest embodied energy of any of the construction materials. Paper production from trees requires much more energy. There is some energy saving in recycling, as recycled paper substitutes for pulp derived from wood chips. Growing crops for food also requires energy. The energy required for plants to grow comes from the sun, but there are additional energy inputs from fertiliser and farm machinery to speed up the growth process and vastly improve crop yields. If grains are used as animal feed, then the energy inputs are much larger than the dietary energy output—the larger the animal and the longer it is fattened up before slaughter, the more inefficient the process. The use of crops to make fuel for electrical power generation or for processing into liquid fuels is horribly inefficient. The problem is simple—the plants do not grow fast enough!

2021 ◽  
Vol 2069 (1) ◽  
pp. 012194
Author(s):  
Jane Raamets ◽  
Laura Lokko ◽  
Aime Ruus ◽  
Targo Kalamees ◽  
Karin Muoni

Abstract At present buildings contribute a third of total greenhouse gas emissions. There is a need for sustainable solutions and natural materials, which offer low-embodied energy and their low impact has a promising potential as construction alternatives. Hempcrete is a lightweight insulation material, which provides natural, airtight, and vapor-permeable insulation. Straw panels are also natural construction materials and they consist of extruded wheat straw and are surrounded with recycled paper on all sides. There are some risks, which can be associated with the use of such materials - infestation, biological degradation, presence of moisture, and structural degradation. The aim of the study is to determine the critical moisture level and mould resistance of hempcrete and straw panels. The results of this study are valuable to both scientists and structural engineers.


Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 667
Author(s):  
Francesco Montemurro ◽  
Alessandro Persiani ◽  
Mariangela Diacono

Sustainability of agricultural practices is one of the most important issues in organic agriculture and its assessment is crucial. To this aim, evaluating the balance between the energy inputs and outputs in crop rotations could be a valuable tool. Therefore, we compared different management strategies in a four-year organic cropping system, by estimating the energy balance of crop production. Two different living mulches with no-till (B1) and green manure (B2) were compared with a cropping system without cover crop (B3), performing both energy analysis and energy balance. Energy parameters were also evaluated. The energy input of fertilizers and water was more than 55% of the total energy required by the cropping systems, suggesting that these agronomic practices should be tailored by farmers to decrease total energy inputs. The potential energy output was significantly higher in the B1 than the B2 and B3 cropping systems (20% and 54%, respectively). Results indicated that B1 and B2 could enhance the energy outputs without negatively affecting the energy consumption, since these cropping systems also showed higher energy efficiency. The introduction of the cover crop as living mulch combined with no-till could be a powerful tool to enhance systems sustainability, without compromising the crop yields.


2021 ◽  
Vol 896 ◽  
pp. 13-20
Author(s):  
Xiao Yu Wen

As an important factor to measure environmental comfort, humidity control is very important. However, previous dehumidification methods have many defects, such as condensation and adsorbents, which often require a lot of energy. The growing requirements of an indoor environment can stem from the development of living levels and technology. Humidity, as an important factor to measure environmental comfort, affects living and production, and indoor humidity control is an indispensable part of modern architecture. However, there are many defects in the previous dehumidification methods, such as condensation dehumidification, which often requires a lot of energy. Traditional adsorbents (such as zeolite silica and activated alumina) have problems with fragile structures or high regeneration temperatures. In this paper, an indoor dehumidification device based on the porous metal-organic framework {MOF-801, Zr6O4(OH)4(Fumarate)6}, can realize the indoor dehumidification process only by using a small amount of solar energy (1 kilowatt per square meter). The device is expected to remove 0.2113 kg/h of moisture per square meter MOF-801, only needs a few additional energy inputs.


2015 ◽  
Vol 49 (3) ◽  
pp. 1936-1945 ◽  
Author(s):  
Manish K. Dixit ◽  
Charles H. Culp ◽  
Jose L. Fernandez-Solis

Author(s):  
George Rocha ◽  
Simon Reynolds ◽  
Theresa Brown

Solar Turbines Incorporated has combined proven technology and product experience to develop the new Taurus 65 gas turbine for industrial power generation applications. The single-shaft engine is designed to produce 6.3 megawatts of electrical power with a 33% thermal efficiency at ISO operating conditions. Selection of the final engine operating cycle was based on extensive aerodynamic-cycle studies to achieve optimum output performance with increased exhaust heat capacity for combined heat and power installations. The basic engine configuration features an enhanced version of the robust Centaur®50 air compressor coupled to a newly designed three-stage turbine similar to the Taurus 70 turbine design. Advanced cooling technology and materials are used in the dry, lean-premix annular combustor, consistent with Solar’s proven SoLoNOx™ combustion technology, capable of reducing pollutant emissions while operating on standard natural gas or diesel liquid fuels. Like the Titan™ 130 and Taurus 70 products, a traditional design philosophy has been applied in development of the Taurus 65 gas turbine by utilizing existing components, common technology and product experience to minimize risk, lower cost and maximize durability. A comprehensive factory test plan and extended field evaluation program was used to validate the design integrity and demonstrate product durability prior to full market introduction.


Author(s):  
Atiq U. Zaman ◽  
Juliet Arnott ◽  
Kate Mclntyre ◽  
Jonathon Hannon

This study analyses the case study of a deconstruction project called the ‘Whole House Reuse’ (WHR) which aimed, firstly, to harvest materials from a residential house, secondly, to produce new products using the recovered materials, and thirdly, to organize exhibition for the local public to promote awareness on resource conservation and sustainable deconstruction practices. The study applies characterization of recovered materials through deconstruction. In addition to the material recovery, the study assesses the embodied energy saving and greenhouse gas emission abatement of the deconstruction project. Around twelve tonnes of various construction materials were harvested through a systematic deconstruction approach, most which would otherwise be disposed to landfill in the traditional demolition approach. The study estimates that the recovered materials could potentially save around 502,158MJ of embodied energy and prevent carbon emission of around 27,029kg (CO2e). Deconstruction could eventually contribute to New Zealand’s national emission reduction targets. In addition, the project successfully engages local communities and designers to produce 400 new products using the recovered materials and exhibited to the local people. The study concludes that there is a huge prospect in regard to resource recovery, emission reduction, employment and small business opportunities using deconstruction of the old house. The socio-cultural importance of the WHR project is definitely immense; however, the greater benefits of such projects are often ignored and remain unreported to wider audiences as most of the external and environmental costs have not been considered in the traditional linear economy. It is acknowledged that under a favourable market condition and with appropriate support from local communities and authorities, deconstruction could contribute significantly to resource conservation and environmental protection despite its requirement of labour intensive efforts.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Deepak Bansal ◽  
V. K. Minocha ◽  
Arvinder Kaur ◽  
Vaidehi A. Dakwale ◽  
R. V. Ralegaonkar

Embodied energy and cost of construction of any building depends upon the consumption of resources, more specifically construction materials. In housing clusters, the spaces provided for horizontal and vertical circulation of occupants such as corridors and contribute in the built-up area of individual unit without any increase in the usable/carpet area. Thus, an efficient architectural planning of common circulation spaces plays a major role in lowering the built-up-to-carpet area ratio of individual housing unit in clusters. This may, thus, result in lesser embodied energy and maximum area availability for occupant usage. In the present study, 30 clusters of Indian affordable housing units (IAHUs) of similar typology and different architectural designs are analyzed. The built-up and carpet area of each IAHU are estimated, and the ratio of the built-up to carpet area is calculated. Detailed estimates of construction materials for each IAHU is prepared, and cost of construction and embodied energy is calculated. The calculations of embodied energy and construction cost are done for major construction materials, viz., cement, steel, bricks, sand, and coarse aggregate and compared with different built-up-to-carpet area ratio. The study of IAHUs concludes that a variation of 1.30 to 1.62 in the built-up area-to-carpet area ratio results in variation in construction cost (INR 13,425.00 to 20,138.00 per m2 carpet area) and embodied energy (4–6.5 GJ per m2 carpet area). Analysis suggests that the IAHU with a lower built-up-to-carpet area ratio exhibits reduction in the cost of construction and embodied energy simultaneously. Thus, an efficient architectural design plays a major role in improving the sustainability of IAHUs and built-up-to-carpet area ratio is an important indicator of sustainability.


Author(s):  
Moslem Sami ◽  
Habib Reyhani

This study evaluated the impacts of cotton farming on the climate changes in terms of energy and greenhouse gas (GHG) emission indices. Energy consumption pattern and sensitivity of energy inputs were evaluated and share of each input in GHG emissions was determined in the form of direct and indirect emissions for cotton farms in Golestan province of Iran. The total energy input and energy output were calculated to be 34,424.19 and 41,496.67 MJ/ha respectively. The share of fertilizers by 45.0 % of total energy inputs was the highest. This was followed by energies of fuel (18.4 %) and irrigation (17.9 %) respectively. Fertilizers and fuels were also the biggest producers of GHGs in the farms with shares of 61.95 and 24.32 % of total GHGs emission. Energy ratio, energy balance, energy intensity and energy productivity were found as 1.21, 7,072.48 MJ/ha, 9.79 MJ/kg and 0.10 kg/MJ, respectively. Results of sensitivity analysis indicated that the cotton production was more sensitive to energies of seed and human labour than other inputs and an additional use of 1 MJ of each of these inputs would lead to a change in the yield by −0.75 and 0.73 kg/ha, respectively. The results also showed, in the process of cotton farming 897.80 and 1177.67 kg CO2 – equivalent of direct and indirect GHG were emitted per hectare respectively.


1970 ◽  
Vol 37 (3) ◽  
pp. 481-491 ◽  
Author(s):  
F. J. Gordon ◽  
T. J. Forbes

SummaryEight lactating cows were used in a Latin square experiment, to study the associative effects of level of energy and protein intake on milk yield and composition. Four diets were used, supplying 80 and 120% of estimated energy requirements and 80 and 120% of estimated protein requirements. The level of energy intake significantly affected milk yield, milk energy output, percentage butterfat, ash and non-protein nitrogen. The level of protein intake only significantly affected milk energy output and the non-protein nitrogen content of the milk. Although only the interaction of the effects of energy and protein intake on the milk content of solidsnot-fat (SNF) and ash was significant, it was evident that the effect of each of these factors on milk yield or composition was related to the level of the other in the diet.Input-output relationships within each protein level were used to compute the response in milk energy output and bodyweight change to a change in energy intake. These showed a greater partitioning of additional energy toward milk energy output with the high than with the low protein level. Multiple regression analysis within each level of protein intake was used to partition energy intake between that used for maintenance, milk energy output and liveweight change. The results showed efficiencies of utilization of metabolizable energy for milk output of 63 and 50% on the high- and low-protein diets, respectively.Nitrogen balance data are presented.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Andrea Parisi Kern ◽  
Renata Postay ◽  
Eduardo Reuter Schneck ◽  
Mauricio Mancio ◽  
Marco Aurélio Stumpf González ◽  
...  

PurposeThe central motivation for this study was to examine alternatives against the apartment area reduction as a safe way to reduce construction costs, adopted by many construction companies. From the building economic compactness index concept, it was studied the cost and environmental impacts (material consumption, embodied energy – EE and CO2 emission).Design/methodology/approachThe research strategy takes advantage of a case study aiming to investigate the relation between design characteristics related to area (m²) and building economic compactness index (%) with cost (Research Stage 1) and with environmental impacts: (Research Stage 2). The study involved real data from social housing projects, chosen in terms in terms of very similar features like size, area and constructive method (constants), however, with dissimilar compactness (variable).FindingsThe lack of direct relation between area and cost signs the importance of including the cost of vertical plans considered in the economic compactness building. The higher the economic compactness index, the lower the cost, the lower the amount of material, EE and CO2 emission parameters. However, due to the wide range of EE and CO2 values available, the reduction in the amount of materials achieved by increasing building economic compactness index may not be reflected in EE and CO2 gains.Research limitations/implicationsAs the limitation of this study, it must be taken into account a limited number of case buildings and the fact that the analysis is dependent on the reliability and accuracy of the data provided by constructors and the available information of EE and CO2 emission. As well discussed in the literature, the consistent database is a great challenge for the construction sector.Originality/valueThere might be alternatives to higher areas with relatively low-cost increments since results from buildings with the same area present different cost estimative and suggest a strong relationship with the economic compactness index. The large variation of EE and CO2 emission data indicates that reductions obtained by compactness increase may be impaired if the construction materials are produced with high levels of EE and CO2 emission. Thus, there must be an integrated effort on the part of designers (design and material specification) and manufacturers (material production), since isolated solutions may not be enough.


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