Aluminum Metal Advancements in Sustainability

Can the idea of sustainability be determined by metrics?  The answer is “Of course”, as any type of improvement can be measured. We understand it is far more efficient to recycle aluminum than it is to produce it the first time, which we call this value embodied energy.  However, since refining represents a significant proportion of manufactured costs there becomes a premium on recycling used aluminum.  Not only are the savings in energy, they are also in emissions of GHG’s.

Novelis reports.

“Recycling aluminum produces 95 percent fewer greenhouse gas (GHG) emissions and requires 95 percent less energy than primary aluminum production, enabling Novelis to achieve lower GHG emissions despite increasing global production capacity.” (1)

Novelis also reports improvements in Energy Intensity and Water Intensity metrics.

Significant gains were also made in fiscal 2016 as it relates to water and energy intensity. Novelis achieved a 22 percent reduction in water intensity and a 24 percent reduction in energy intensity for the 2007-2009 baseline.  (1)

Novelis Core Business

Novelis produces close to 20 percent of the world’s rolled aluminum products and we are strategically located on the four continents where aluminum demand is the greatest: North America, South America, Europe and Asia. Our dedication, innovation and leadership have made us the number one producer of rolled aluminum in Europe and South America, and the number two producer in North America and Asia. We also are the world’s largest recycler of used beverage cans, which comprise a critical input to our operations. Quite simply, recycling is a core element of our manufacturing process.  (2)

Figure 1:  Novelis Opens World’s Largest Aluminium Recycling Facility (3)

Novelis has officially opened the “world’s largest” aluminium recycling centre located adjacent to the company’s rolling mill in Nachterstedt, Germany and costing over £155m.

The recycling centre will process up to 400,000 metric tons of aluminium scrap annually, turning it back into high-value aluminium ingots to feed the company’s European manufacturing network.

“The Nachterstedt Recycling Centre is a significant step toward our goal to be the world’s low-carbon aluminium sheet producer, shifting our business model from a traditional linear approach to an increasingly closed-loop model,” said Phil Martens, president and chief executive officer of Novelis.  (3)

References:

(1) http://www.prnewswire.com/news-releases/novelis-reports-significant-gains-in-sustainability-300379847.html

(2) http://novelis.com/about-us/assets-and-capabilities/

(3) http://www.ciwm-journal.co.uk/novelis-opens-worlds-largest-aluminium-recycling-facility/

Related Posts:

Embodied Energy https://duanetilden.com/2014/12/10/embodied-energy-a-measure-of-sustainability-in-buildings-construction/

Energy Efficiency  https://duanetilden.com/2016/06/19/measuring-and-monitoring-energy-efficiency/

 

Aluminum, a Quantum Leap in Renewable Energy Storage

The future for the metal aluminum has never looked better, for the great investment it represents as a multi-faceted energy efficiency lending material, electrical energy storage medium (battery), and for the advancement of renewable energy sources.  These are spectacular claims, and yet in 1855 aluminum was so scarce it sold for about 1200 $/Kg (1) until metallurgists Hall & Heroult invented the modern smelting process over 100 years ago (2).

Image result for aluminum electrolysis

Figure 1.  Schematic of Hall Heroult Aluminum Reduction Cell (3)

 

Aluminum is an energy intensive production process.  High temperatures are required to melt aluminum to the molten state.  Carbon electrodes are used to melt an alchemical mixture of alumina with molten cryolite, a naturally occurring mineral.  The cryolite acts as an electrolyte to the carbon anode and cathodes.  Alumina (Al2O3) also known as aluminum oxide or Bauxite is fed into the cell and dissolved into the cryolite, over-voltages reduce the Al2O3 into molten aluminum which pools at the bottom of the cell and is tapped out for further refining.

Aluminum Smelting Process as a Battery

The smelting of Aluminum is a reversible electrolytic reaction, and with modifications to current plant design it is possible to convert the process to provide energy storage which can  be tapped and supplied to the electrical grid when required.  According to the research the biggest challenge to this conversion process is to maintain heat balances of the pots when discharging energy to prevent freeze-up of the cells.  Trimet Aluminum has overcome this problem by incorporating shell heat-exchange technology to the sides of the cell to maintain operating temperatures.  Trial runs with this technology have been positive where plans are to push the technology to +/- 25% energy input/output.  If this technology is applied to all 3 Trimet plants in Germany, it is claimed that up to 7700 MWh of electrical storage is possible (4).

Trimet Aluminum SE, Germany’s largest producer of the metal, is experimenting with using vast pools of molten aluminum as virtual batteries. The company is turning aluminum oxide into aluminum by way of electrolysis in a chemical process that uses an electric current to separate the aluminum from oxygen. The negative and positive electrodes, in combination with the liquid metal that settles at the bottom of the tank and the oxygen above, form an enormous battery.

By controlling the rate of electrolysis, Trimet has been able to experiment with both electricity consumption and storage.  By slowing down the electrolysis process, the plant is able to adjust its energy consumption up and down by roughly 25 percent.  This allows the plant to store power from the grid when energy is cheap and abundant and resell power when demand is high and supply is scarce. (5)

Related image

Figure 2. TRIMET Aluminium SE Hamburg with emission control technology (6)

 

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Figure 3.  Rio Tinto Alcan inaugurates new AP60 aluminum smelter in Quebec (7)

Aluminum as a Material and it’s Energy Efficiency Properties

Aluminum and it’s alloys generally have high strength-to-weight ratio’s and are often specified in the aircraft industry where weight reduction is critical.  A plane made of steel would require more energy to fly,  as the metal is heavier for a given strength.  For marine vessels, an aluminum hull structure, built to the same standards, weighs roughly 35% to 45% less than the same hull in steel (8). Weight reduction directly converts to energy savings as more energy would be required to propel the aircraft.

Other modes of transportation, including automobiles, trucking, and rail transport may similarly also benefit from being constructed of lighter materials, such as aluminum.  Indeed this would continue the long-standing trend of weight reduction in the design of vehicles.  The recent emergence of electric vehicles (EV’s) have required weight reduction to offset the high weight of batteries which are necessary for their operations.  The weight reduction translates into longer range and better handling.

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Figure 4.  Tesla Model S (9)

 

In the 1960s, aluminium was used in the niche market for cog railways. Then, in the 1980s, aluminium emerged as the metal of choice for suburban transportation and high-speed trains, which benefited from lower running costs and improved acceleration. In 1996, the TGV Duplex train was introduced, combining the concept of high speed with that of optimal capacity, transporting 40% more passengers while weighing 12% less than the single deck version, all thanks to its aluminium structure.

Today, aluminium metros and trams operate in many countries. Canada’s LRC, France’s TGV Duplex trains and Japan’s Hikari Rail Star, the newest version of the Shinkansen Bullet train, all utilize large amounts of aluminium.  (10)

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Figure 5.   Image of Japanese Bullet Train  (11)

Aluminum For Renewable Energy

One of the biggest criticisms against renewable technologies, such as solar and wind has been that they are intermittent, and not always available when demand demand for energy is high.  Even in traditional grid type fossil fuel plants it has been necessary to operate “peaker plants” which provide energy during peak times and seasons.

In California, recent technological breakthroughs in battery technology have been seen as a means of providing storage options to replace power plants for peak operation. However, there remains skepticism that battery solutions will be able to provide the necessary storage capacity needed during these times (12).  The aluminum smelter as an energy provider during these high demand times may be the optimum solution needed in a new age renewables economy.

The EnPot technology has the potential to make the aluminium smelting industry not only more competitive, but also more responsive to the wider community and environment around it, especially as nations try to increase the percentage of power generated from renewable sources.

The flexibility EnPot offers smelter operators can allow the aluminium industry to be part of the solution of accommodating increased intermittency.  (13)

References:

(1)  http://www.aluminum-production.com/aluminum_history.html

(2)  http://www.aluminum-production.com/Basic_functioning.html

(3)  http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532000000300008

(4)  The ‘Virtual Battery‘ – Operating an Aluminium Smelter with Flexible Energy Input.  https://energiapotior.squarespace.com/s/Enpot-Trimet-LightMetals2016.pdf

(5)  http://www.metalsproclimate.com/metals-pro-climate/best-practice/reduction-of-pfc-process-emissions

(6) http://www.sauder.ubc.ca/Faculty/Research_Centres/Centre_for_Social_Innovation_and_Impact_Investing/Programs/Clean_Capital/Clean_Capital_News_Archive_2014/Aluminum_smelters_could_act_as_enormous_batteries

(7)  http://www.canadianmetalworking.com/2014/01/rio-tinto-alcan-inaugurates-new-ap60-aluminum-smelter-in-quebec/

(8)  http://www.kastenmarine.com/alumVSsteel.htm

(9)  http://www.greencarreports.com/news/1077672_2012-tesla-model-s-is-aluminum-its-secret-weapon

(10)  http://transport.world-aluminium.org/en/modes/trainssubways.html

(11)  http://www.aluminiumleader.com/focus/aluminium_carriages_help_provide_high_speed_rail_service/

(12)  http://www.bloomberg.com/news/articles/2015-12-22/batteries-gaining-favor-over-gas-peaker-plants-in-california

(13)  http://www.energiapotior.com/the-virtual-battery

Transitioning Oil & Gas Wells to Renewable Geothermal Energy

Infinity Turbine 2016 ROT IT50

Figure 1:  Radial Outflow Turbine Generator – Organic Rankine Cycle – ORC Turbine (1)

Existing oil and gas wells offer access to untapped sources of heat which can be converted to electricity or used for other energy intensive purposes.  This includes many abandoned wells, which can be reactivated as power sources.  These wells, in many cases “stranded assets” have been drilled, explored, and have roads built for access.  This makes re-utilization of existing infrastructure cost-effective while minimizing harm to the environment associated with exploration.

In a recently published article in Alberta Oil, an oil & gas industry magazine they point out many of the benefits of converting existing and abandoned wells to geothermal energy.

A recent Continental Resources-University of North Dakota project in the Williston Basin is producing 250 kW of power from two water source wells. The units fit into two shipping containers, and costs US$250,000. This type of micro-generation is prospective in Alberta, and a handful of areas also have potential for multi-MW baseload power production.

In addition to producing power, we can use heat for farming, greenhouses, pasteurization, vegetable drying, brewing and curing engineered hardwood. Imagine what Alberta’s famously innovative farmers and landowners would accomplish if they were given the option to use heat produced from old wells on their properties. Northern communities, where a great many oil and gas wells are drilled nearby, can perhaps reap the most benefits of all. Geothermal can reduce reliance on diesel fuel, and provide food security via wellhead-sourced, geothermally heated, local greenhouse produce. (2)

Water can be recirculated by pumps to extract heat from the earth, and through heat exchangers be used as a source of energy for various forms of machines designed to convert low grade waste heat into electricity.  The Stirling Cycle engine is one such mechanical device which can be operated with low grade heat.  However recent developments in the Organic Rankine Cycle (ORC) engine seem to hold the greatest promise for conversion of heat to electricity in these installations.

In a “boom or bust” industry subject to the cycles of supply and demand coupling a new source of renewable energy to resource extraction makes sense on many fronts.  It could be an economic stimulus not only to the province of Alberta, but throughout the world where oil and gas infrastructure exists, offering new jobs and alternative local power sources readily available.

References:

(1)  http://www.infinityturbine.com/

(2)  http://www.albertaoilmagazine.com/2016/10/geothermal-industry-wants-abandoned-wells/

Related Blog Posts:

  1. https://duanetilden.com/2016/01/14/alberta-energy-production-and-a-renewable-future/
  2. https://duanetilden.com/2014/12/21/renewable-geothermal-power-with-oil-and-gas-coproduction-technology-may-be-feasible/
  3. https://duanetilden.com/2015/07/25/a-new-era-for-geothermal-energy-in-alberta/
  4. https://duanetilden.com/2015/07/27/oil-well-waste-water-used-to-generate-geothermal-power/
  5. https://duanetilden.com/2013/10/29/supercritical-co2-refines-cogeneration-for-industry/

Thermoelectric Materials: Converting Heat to Electricity

When we think of using electricity one of the prevalent uses is to provide a heat source.  We see this in our everyday lives as ranges and ovens, microwaves, kettles, hot water tanks, baseboard heaters, as well as other applications.  So how about reversing the process and capturing heat and directly converting to electricity, is this possible?  As it happens there is a classification of materials which have a property called a thermoelectric effect.

Boosting energy efficiency is an important element of the transition to a sustainable energy system. There are big savings to be made. For example, less than half the energy content of diesel is actually used to power a diesel truck. The rest is lost, mostly in the form of heat. Many industrial processes also deal with the problem of excessive .

That’s why many research teams are working to develop that can convert waste heat into energy. But it’s no easy task. To efficiently convert heat to electricity, the materials need to be good at conducting electricity, but at the same time poor at conducting heat. For many materials, that’s a contradiction in terms.

“One particular challenge is creating thermoelectric materials that are so stable that they work well at high temperatures,” says Anders Palmqvist, professor of materials chemistry, who is conducting research on thermoelectric materials. (1)

2dthermoelec.jpg

Image 1:  The enlarged illustration (in the circle) shows a 2D electron gas on the surface of a zinc oxide semiconductor. When exposed to a temperature difference, the 2D region exhibits a significantly higher thermoelectric performance compared to that of bulk zinc oxide. The bottom figure shows that the electronic density of states distribution is quantized for 2D and continuous for 3D materials. Credit: Shimizu et al. ©2016 PNAS

The thermoelectric effect is not as efficient as converting electricity to heat, which is generally 100% efficient.  However, with waste energy streams even a small conversion rate may return a significant flow of usable electricity which would normally go up a stack or out a tailpipe.

The large amount of waste heat produced by power plants and automobile engines can be converted into electricity due to the thermoelectric effect, a physics effect that converts temperature differences into electrical energy. Now in a new study, researchers have confirmed theoretical predictions that two-dimensional (2D) materials—those that are as thin as a single nanometer—exhibit a significantly higher thermoelectric effect than three-dimensional (3D) materials, which are typically used for these applications.

The study, which is published in a recent issue of the Proceedings of the National Academy of Sciences by Sunao Shimizu et al., could provide a way to improve the recycling of into useful energy.

Previous research has predicted that 2D materials should have better thermoelectric properties than 3D materials because the electrons in 2D materials are more tightly confined in a much smaller space. This confinement effect changes the way that the electrons can arrange themselves. In 3D materials, this arrangement (called the density of states distribution) is continuous, but in 2D materials, this distribution becomes quantized—only certain values are allowed. At certain densities, the quantization means that less energy is required to move electrons around, which in turn increases the efficiency with which the material can convert heat into . (2)

 

Related Articles:

References:

  1. http://phys.org/news/2016-06-track-electricity.html#jCp
  2. http://phys.org/news/2016-06-electricity-dimensions.html#jCp

Minimum Efficiency Standards for Electric Motors to Increase – DOE

DOE’s analyses estimate lifetime savings for electric motors purchased over the 30-year period that begins in the year of compliance with new and amended standards (2016-45) to be 7.0 quadrillion British thermal units (Btu). The annualized energy savings—0.23 quadrillion Btu—is equivalent to 1% of total U.S. industrial primary electricity consumption in 2013.

Source: www.eia.gov

>” Nearly half of the electricity consumed in the manufacturing sector is used for powering motors, such as for fans, pumps, conveyors, and compressors. About two thirds of this machine-drive consumption occurs in the bulk chemicals, food, petroleum and coal products, primary metals, and paper industries. For more than three decades the efficiency of new motors has been regulated by federal law. Beginning in mid-2016, an updated standard established this year by the U.S. Department of Energy (DOE) for electric motors will once again increase the minimum efficiency of new motors.

The updated electric motor standards apply the standards currently in place to a wider scope of electric motors, generating significant estimated energy savings. […]

Legislation has increased the federal minimum motor efficiencies requirements over the past two decades, covering motors both manufactured and imported for sale in the United States. The Energy Policy Act of 1992 (EPAct) set minimum efficiency levels for all motors up to 200 horsepower (hp) purchased after October 1997. The U.S. Energy Independence and Security Act (EISA) of 2007 updated the EPAct standards starting December 2010, including 201-500 hp motors. EISA assigns minimum, nominal, full-load efficiency ratings according to motor subtype and size. The Energy Policy and Conservation Act of 1975 also requires DOE to establish the most stringent standards that are both technologically feasible and economically justifiable, and to periodically update these standards as technology and economics evolve.

Motors typically fail every 5 to 15 years, depending on the size of the motor. When they fail they can either be replaced or repaired (rewound). When motors are rewound, their efficiencies typically diminish by a small amount. Large motors tend to be more efficient than small motors, and they tend to be used for more hours during the year. MotorMaster+ and MotorMaster+ International, distributed by the U.S. Department of Energy and developed by the Washington State University Cooperative Extension Energy Program in conjunction with the Bonneville Power Administration, are sources for cost and performance data on replacing and rewinding motors.

Improving the efficiency of motor systems, rather than just improving the efficiency of individual motors, may hold greater potential for savings in machine-drive electricity consumption. Analysis from the U.S. Department of Energy shows that more than 70% of the total potential motor system energy savings is estimated to be available through system improvements by reducing system load requirements, reducing or controlling motor speed, matching component sizes to the load, upgrading component efficiency, implementing better maintenance practices, and downsizing the motor when possible.”<

 

See on Scoop.itGreen Energy Technologies & Development

Continuous Monitoring Solution Designed for Facility and Energy Management

Verisae and Ecova partner to combine technology and service across nearly 3,000 facilities for an innovative and smart operational approach …

 

image source: http://energymanagementsystems.org/faqs-on-developing-energy-management-systems/

Source: www.virtual-strategy.com

>” Verisae, a leading global provider of SaaS solutions that drive cost reductions in maintenance, energy, mobile workforces, and environmental management, and Ecova, a total energy and sustainability management company, are pleased to announce the success of their growing partnership to help multisite companies solve their toughest energy, operations, and maintenance challenges.

The continuous monitoring solution combines Verisae’s Software-as-a-Service (SaaS) technology platform with Ecova’s Operations Control Center (OCC) to empower data-driven decision making. The solution analyses operational data in real-time, and has the capability to look for issues and anomalies to predict equipment failure and automatically identify inefficiencies causing higher energy consumption.

Ecova’s fully-staffed 24/7/365 OCC investigates inbound service calls, alarms, telemetry data, and work orders to determine the source of energy, equipment, and system faults and, where possible, corrects issues remotely before they escalate into financial, operational, or comfort problems. Trouble tickets and inbound calls are captured and tracked in the Verisae platform to provide companies with visibility into any operational issues. Combining data analytics that flag potentially troubling conditions with a service that investigates and resolves issues increases operational efficiencies and improves energy savings.

“Companies are constantly challenged to cut costs while maintaining quality, performance, and comfort,” says Jerry Dolinsky, CEO of Verisae. “Our combined solution helps clients address these challenges so they can reduce costs and improve operational efficiencies without impacting value.”

[…] “<

See on Scoop.itGreen Energy Technologies & Development

The Ripple Effect of Energy Efficiency Investment

“The term “multiple benefits” has emerged to describe the additional value that emerges with any energy performance improvement. The benefits that occur onsite can be especially meaningful to manufacturing, commercial, and institutional facilities. Energy efficiency’s positive ripple effects include increased productivity and product quality, system reliability, and more. ”

 

Source: aceee.org

>” […]  Over the past few decades, researchers have documented numerous cases of energy efficiency improvements—almost always focusing exclusively on energy savings. Non-energy benefits are often recognized, but only in concept. ACEEE’s new report, Multiple Benefits of Business-Sector Energy Efficiency, summarizes what we know about the multiple benefits for the business sector. True quantification of these benefits remains elusive due to a lack of standard definitions, measurements, and documentation, but also in part because variations in business facility design and function ensures that a comprehensive list of potential energy efficiency measures is long, varied, and often unique to the facility.

To give some concrete examples of non-energy benefits at work: Optimizing the use of steam in a plywood manufacturing plant not only reduces the boiler’s natural gas consumption, it also improves the rate of throughput, thus increasing the plant’s daily product yield. A lighting retrofit reduces electricity consumption while also introducing lamps with a longer operating life, thus reducing the labor costs associated with replacing lighting. In many instances, monitoring energy use also provides insights into water or raw material usage, thereby revealing opportunities to optimize manufacturing inputs and eliminate production waste. By implementing energy efficiency, businesses can also boost their productivity. This additional value may make the difference in a business leader’s decision to pursue certain capital investment for their facility.

Meanwhile, energy resource planners at utilities and public utility commissions recognize the impact of large-facility energy demands on the cost and reliability of generation and transmission assets. By maximizing consumer efficiency, costs are reduced or offset throughout a utility system. So the ability to quantify the multiple benefits of investing in energy efficiency, if only in general terms, is an appealing prospect for resource planners eager to encourage greater participation in efficiency programs.

Unfortunately, our research shows that this quantification rarely happens, even though the multiple benefits are frequently evident. A number of studies offer measurement methodologies, anticipating the availability of proper data. When these methodologies are employed with limited samples, we see how proper accounting of non-energy benefits dramatically improves the investment performance of energy efficiency improvements—for example, improving payback times by 50% or better. Samples may provide impressive results, but the data remains too shallow to confidently infer the value to come for any single project type implemented in a specific industrial configuration. Developing such metrics will require more data.  […]”<

 

See on Scoop.itGreen & Sustainable News

Commercial ORC Used for Waste Heat Recovery on Industrial Electric Arc Furnace

Turboden, a group company of Mitsubishi Heavy Industries, has implemented the first ORC-based heat recovery plant on an Electric Arc Furnace (EAF) in the world

Source: www.pennenergy.com

>” […] The heat recovery system was started up on December 2013. It is connected to the off-gas treatment system of the melting electric furnace. The recovered energy reduces net power consumption, allowing significant CO2 reduction.

In addition to electricity production, the remaining portion of the steam is fed into the Riesa Municipal steam supply system and used in a nearby tire factory production process.

Turboden designs, develops and implements generation plants, allowing reduction of industrial energy consumption and emissions containment through heat recovery from unexploited residual heat streams and exhaust gases in production processes and power plants.

This technology is best applied in energy-intensive industries such as glass, cement, aluminum, iron & steel, where production processes typically generate exhaust gases above 250°C.

These new plants not only provide advantages in terms of environmental sustainability, emissions reduction, increased industrial process efficiency and improved business performance, but they also represent opportunities for increased competitiveness.”<

See on Scoop.itGreen Energy Technologies & Development

Organic Rankine Cycle (ORC) Heat Recovery Technology For Ships

The company has developed a marine Organic Rankine Cycle (ORC) system for waste heat recovery and power generation that could reduce fuel consumption by up to 10%.

Source: www.motorship.com

“> […] Enertime’s ORC system produces between 500kW and 1MW of electrical power depending on the available amount of heat. The unit is based on a tailor-made axial turbine and is specifically designed to work in the marine environment. The development work has involved shipyards, shipowners and a classification society, says Mr David.

“Compared to a steam power cycle, ORC systems need very low maintenance, display good part-load efficiency, high availability and can be operated without permanent monitoring,” he said. “Daily operation and maintenance can be carried out without specific qualification.”

The ORC system can work with any kind of heat source. The unit can recover heat from a number of different sources singly or in combination including low-temperature jacket cooling from engines, steam or thermal oil systems and pressurised hot water. Exhaust gas from engines or auxiliaries is the main available heat on board ships, and it can be collected through an exhaust gas heat exchanger and brought to the ORC unit using steam, pressurised water or thermal oil. […]

The ORC layout is flexible and the unit can also be installed as a retrofit where it is possible to adapt the layout of the machinery to specific constraints by splitting it on different levels, for example.

“This kind of system would be very interesting for bulk carriers, small to medium size oil tankers, ferry boats, small container ships… with payback time between two to five years,” […]”<

 

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BEMS for Smaller Buildings $6 Billion Growth from 2014 to 2022

The market for building energy management systems (BEMS) for small and medium-sized commercial buildings is expanding as building owners and managers demand more energy savings and easier ways to manage energy use in their facilities, notes Navigant Research.

Source: www.achrnews.com

>” […]“Lower expenditures on energy management in the small and medium-sized building market, along with the lower penetration of advanced controls and building management systems, has limited the penetration of BEMS in this sector,” said Noah Goldstein, research director with Navigant Research. “Given the increasing importance of energy savings, however, BEMS are poised to be a tool that enables savings in both cost and carbon emissions in small and medium buildings.”

The most rapid growth in the BEMS market for smaller buildings, according to the report, is expected to occur in Europe and Asia Pacific, where new construction and regulation are promoting the installation of BEMS equipment and in turn creating demand for associated services and software. In the North American market, BEMS sales are expected to be concentrated in software, driven by utility and regulatory initiatives that promote energy efficiency and building energy reporting. […]”<

 

See on Scoop.itGreen Building Operations – Systems & Controls, Maintenance & Commissioning