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Types of power production Hydro: ● Reservoir ● Potential energy to electrical ● Control gate ● Water flows to powerhouse ● Travels through penstock ● Turbine and generator ● The rotating wheel with a row of curved blades is called a runner ● the water rushing in enters a large circular tube that surrounds the runner. This tube is called the scroll case ● Wicket gates are a series of interconnected openings that operate in unison to control the flow of the water from the scroll case into the runner ● The water’s pressure and speed cause the runner to turn

Wind: ● 40 acres of wind space

● Wind turbines sit high atop towers, hundreds of feet above the ground so the wind can reach them without being blocked by obstacles such as trees, hills, or buildings. ● The process begins when the rotor blades turn in the wind and transfer the wind power to the rotor hub ● The low speed shaft connects the rotor hub to the gearbox, which sits between the low speed shaft and the high speed shaft ● Gears inside the box increase the shaft speeds so that the high speed shaft turns much faster than the low speed shaft. ● The high speed shaft turns an electromagnet within the electrical generator, which converts the mechanical energy into electrical energy. ● transformer where the voltage is increased. ● Many wind turbines have a computer control system that makes adjustments when the wind changes speed or direction. ● The system uses an anemometer to measure wind speed. The system starts the wind turbine when the wind reaches 8mph. ● If the wind blows too hard, the controller engages a brake to stop the rotor blades from turning to prevent damage ● wind vane connected to the control system detects changes in wind direction. The control system then signals motors in the yaw drive to keep the rotor facing into the wind. Normally the turbine will rotate only a few degrees at a time as the wind changes its direction.

Combustion Turbine ● generating electricity begins when filtered outside air is pulled into a compressor.

● The air is forced through the compression chamber by a series of rotating and stationary blades. As the air travels through the compressor, it's pressure and temperature increase as it's forced into a smaller and smaller space. ● The high pressure air from the compressor is directed to fuel injectors that release fuel into the air. Within the cans, a flame ignites the mixture resulting in hot gases that expand into the turbine area. ● The hot high pressure gases then blast through the turbine, spinning a series of turbine blades connected to a long shaft. As the shaft turns, it provides mechanical energy to turn the blades of the compressor, and also rotates an electromagnet within the electrical generator. ● The rotating electromagnet within the generator creates an electrical charge. The electrical charge creates an electrical current that travels through tubular aluminum conductors to a step up transformer outside the plant where it's voltage is increased. ● After the hot gases turn the combustion turbine blades, the gases exit from the turbine as exhaust. However, the gases are still hot and the heat can be recycled through a heat recovery steam generator. ● The hot gases boil the water in the tubes, turning the water into steam. As the water turns to steam, it's pressure increases. ● This high pressure steam is piped to a steam powered turbine as the steam rushes through the turbine, it turns blades attached to a long shaft connected to a generator. ● As the turbine turns the shaft it causes large electromagnets to rotate within the generator, creating an electrical current that is sent to a step up transformer. ● Steam then leaves the steam turbine and passes through a condenser. The steam is turned back into water as it is cooled by a separate water supply, known as circulating water, flowing through the condenser tubes. ● The condensed steam is returned to the heat recovery steam generator where it is again turned into high pressure steam. ● The circulating water is piped to a cooling tower to lower its temperature and is then returned to the condenser to be used again.

Scales: ● By viewing this problem across different scales, different stakeholder groups, and different aspects of the problem, different potential solutions arise.

● As engineers, we tend to be adept at developing technical solutions, but equally important, we need to recognize and appreciate that the best solution for a given problem and context might not be a technical one. ● We need to fully understand the problem, which means viewing it across all relevant scales. 1. Use a decision making process to guide solution-finding 2. Thinking at different scales can lead to a good solution. ● Scale: One size does NOT fit all ● How do potential solutions play out at different spatial scales? ● Increasing solutions → Building site, local, regional, national, global. Also time scales should be considered

Differences between engineers and scientists in terms of decision making ● Engineers: Focus on clients, contracts Applying scientific knowledge Focus on economics Designs ion ● Scientists: Gaining knowledge Less focused on economics Research Impact of engineer’s role in decision making ● Technically feasible ● Ethical ● Legal

● Economically feasible ● All these aspects come together to form sustainability. One needs to recognize the impact of one's personal values ● To inform decision makers: Provide fair and accurate evaluation of the technical information recognize uncertainties and biases ● To advocate: ensure an appropriate process of decision making ● To act with integrity: Behave in an ethical and professional manner ● Main take away: engineers need to be objective thinkers and decision makers, while recognizing their own personal values. Weighted Decision Matrix The key point is that for an engineering decision, we need an objective and systematic method to make and justify our decisions. Well have to balance tradeoffs, and be able to communicate our reasoning to stakeholders. The scores are based on stakeholder satisfaction ● A weighted decision matrix: a tool that uses a matrix. ● The evaluation criteria from the target specifications are on the left and the different options for the design concepts and different choices are listed on the top. ● We also need a column for the criteria weights, as in how important one criteria is compared to the rest. ● In our cardboard chair criteria, all of our criteria was weighted the same, so 10 criteria/100 points = 10% weight each. ● Sensitivity of results: the effect of weights. ● If we change the %weight of the criteria, the scores change but the results are the same. ● This is a desirable result, because it shows that even if stakeholder needs are adjusted a bit, our decision of choosing optimal solution is unaffected. Target specifications: criteria + requirements Strengths:

● Allows options to be quantified. ● Subjective opinions can be made objective. ● Decisions documented and can be described/defended. ● Sensitivity studies can be performed

Limitations: ● ● ●

never better than chosen criteria and assigned weights. The WDM assumes criteria are independent. Biases affect weights and scores.

Prototypes ● Reduce risk+cost+resources during design process ● Types of Prototype models: ○ Focused (a part of the whole) or Comprehensive (general look at whole final product) ○ Physical model or Virtual Ex. Chair building process ● ● ● ●

C-sketch- comprehensive and virtual Mini cardboard chairs- comprehensive and physical CAD design on chair joints- focused and virtual Testing joints with cardboard-Focused physical testing

Sustainability: ● Being able to support the human world of people, society, culture, and the economy while protecting and preserving the natural world right now, and more importantly, to be able to continue to do this indefinitely. ● Sustainability is being able to meet the needs of the present without compromising the future.

● Sustainability: the capacity of human society to continue indefinitely within the earth's natural cycles. ● Bearable= no economy ● Equitable= no environment ● Viable= no society

Our real goal is to find solutions that support all 3 dimensions simultaneously. 1. Avoid removing materials from the earth at a rate faster than they are naturally replenished. 2. Avoid making things and releasing substances at a rate faster than they naturally break down. 3. Avoid degrading ecosystems at a rate faster than they can naturally regrow. 4. And, as a society, move towards happiness, well-being, and meeting the needs of all people.

Stages of a Design Process ● ● ● ● ● ●

Stage 0: Identify the problem (identify stakeholders + needs) Stage 1: Study + clarify problem (understand + refine) Stage 2: Generate potential solutions (great quantity of solutions) Stage 3: Identify most promising solution Stage 4: Develop +test solution Stage 5: Implement solution

*ITERATION: Continually revisit previous stages during the process

Stage 3 Steps

● ● ●

Screening: identify and eliminate solutions that don’t meet the requirements Ranking: sort remaining criteria highest to lowest performance Scoring: remaining ideas are analyzed + studied, then quantified by perfomance

Causal loop diagrams: ● ● ● ●

●

a tool used to describe and understand complex systems (nodes + links) (+) for Directly proportional (-) for Inversely proportional What makes systems complex? Factors: 1. not strictly governed by physical laws 2. Human interaction 3. Feedback loops Examples of complex systems 1. Traffic networks 2. Climate 3. Nature

1. Deterministic system: has math to back it up (quantitative) 2. Complex system: (qualitative)

Delay: shown by a “ ll ”, means that it takes time (there is a delay from one node to the other) Reinforcing loop. ● Labeled with an “R” values will keep increasing exponentially(+) ● Labeled with an “B” values will keep decreasing exponentially (-)

System thinking A perspective and a set of tools for viewing complex systems to identify patterns, structures, and interactions between components

Verification and Validation ● ●

Validation: Do the evaluation criteria meet the stakeholders needs Verification: If the needs of the stakeholders are actually fulfilled

Audience What does your audience... 1. ...already know, need to know, and not know about your topic? 2. ...think about your topic? 3. … hope to get out of your presentation? Purpose: ● describes your goals and reasons in delivering the presentation. ● Identify your purpose: why is this information important? a. Inform. To describe, review, instruct, explain, demonstrate… b. Persuade. To convince, influence, recommend, change, justify… Context: ● this refers to everything surrounding your presentation. ● Identify your context: 1. What led to you developing the presentation? 2. What is the setting of the presentation? 3. What other factors related to time, tools, and space are relevant?

Delivering technical presentations ● ● ● ● ●

Delivery Gestures Professionalism Attire Language

What increases energy output of hydroelectric dam? ● Does cause increase: ○ Increase elevation of reservoir from the turbine: More GPE -> Mechanical energy -> electrical energy ● Does not increase ○ Increase size of reservoir: Same rate of flow through the turbine independent of the size of the reservoir. ○ Increased # turbines & penstocks: Challenges of mining engineering ● Cost of extraction can increase when the minerals are very deep into the ground ● The limited supply of certain minerals in the earth ● Extracting the minerals in an environmentally sustainable way...