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1. Discuss the present energy situation in Gandaki Province and explore the potential role of the provincial government in addressing and resolving energy-related difficulties.
Ans:->Gandaki Province is one of the three provinces in Nepal with the highest potential for hydropower generation. However, the province is currently facing a number of energy-related challenges, including:
- Low electrification rate: According to the Nepal Electricity Authority (NEA), only 92.79% of households in Gandaki Province are electrified. This is significantly lower than the national electrification rate of 98.5%.
- High transmission and distribution losses: The NEA estimates that it loses about 8.72% of the electricity it generates in Gandaki Province due to transmission and distribution losses. This is a significant amount of energy that could be used to meet the needs of the province's residents and businesses.
- Dependence on imported electricity: Gandaki Province imports about 20% of the electricity it consumes from India. This dependence on imported electricity makes the province vulnerable to supply disruptions and price volatility.
The provincial government of Gandaki has a number of potential roles to play in addressing and resolving these energy-related challenges. These roles include:
- Investing in new hydropower projects: The provincial government can invest in new hydropower projects to increase the province's generation capacity and reduce its dependence on imported electricity.
- Improving the transmission and distribution network: The provincial government can improve the transmission and distribution network to reduce electricity losses and make it easier for people to access electricity.
- Providing financial assistance to households and businesses: The provincial government can provide financial assistance to households and businesses to help them pay for the cost of electricity.
- Promoting energy efficiency: The provincial government can promote energy efficiency measures to reduce the amount of electricity that people and businesses consume.
By taking these steps, the provincial government of Gandaki can help to improve the province's energy situation and make it easier for people to access affordable and reliable electricity.
In addition to the above, the provincial government can also play a role in:
- Developing policies and regulations to promote the development of renewable energy sources.
- Providing technical assistance to local communities to develop and manage their own micro hydropower projects.
- Raising awareness of energy conservation and efficiency measures.
By taking these steps, the provincial government can help to make Gandaki Province a more sustainable and energy-secure region.
b. What engineering approaches can be employed to enhance building energy efficiency and achieve effective reductions in energy consumption?
Ans: Enhancing building energy efficiency is crucial for reducing energy consumption and minimizing the environmental impact of buildings. Various engineering approaches can be employed to achieve effective reductions in energy consumption in buildings. Here are some key approaches:
1. **Building Envelope Improvements:**
- **Insulation:** Proper insulation in walls, roofs, and floors helps regulate indoor temperatures, reducing the need for heating and cooling.
- **Windows and Glazing:** Installing high-performance windows with low-emissivity coatings and multiple panes can improve thermal insulation while allowing natural light.
- **Air Sealing:** Preventing air leaks through the building envelope enhances energy efficiency by reducing heating and cooling losses.
2. **HVAC (Heating, Ventilation, and Air Conditioning) Upgrades:**
- **High-Efficiency HVAC Systems:** Installing energy-efficient heating and cooling systems, such as heat pumps or variable refrigerant flow (VRF) systems, can significantly reduce energy consumption.
- **Zoning and Controls:** Implementing zoning systems and smart controls enables better temperature regulation in different areas of the building.
- **Regular Maintenance:** Proper maintenance of HVAC systems ensures they operate at peak efficiency.
3. **Energy-Efficient Lighting:**
- **LED Lighting:** Replacing traditional incandescent or fluorescent lights with LED lighting reduces energy consumption and extends bulb lifetimes.
- **Occupancy Sensors:** Installing sensors that detect occupancy and adjust lighting accordingly can avoid unnecessary energy usage.
4. **Renewable Energy Integration:**
- **Solar Panels:** Installing photovoltaic (PV) solar panels on rooftops can generate clean electricity to supplement the building's energy needs.
- **Wind Turbines:** In suitable locations, wind turbines can be employed to harness wind energy for electricity generation.
5. **Building Automation and Control Systems:**
- **Building Management Systems (BMS):** Using centralized control systems helps monitor and manage lighting, HVAC, and other systems for optimal energy use.
- **Smart Thermostats:** These devices learn occupants' preferences and adjust heating and cooling accordingly, reducing energy waste.
6. **Energy-Efficient Appliances and Equipment:**
- **Energy Star-rated Appliances:** Choosing energy-efficient appliances, such as refrigerators, washing machines, and dishwashers, can lower electricity consumption.
- **Efficient Office Equipment:** Using computers, printers, and other office equipment with low energy consumption reduces overall building energy use.
7. **Passive Design Strategies:**
- **Daylighting:** Maximizing natural light through well-designed windows reduces the need for artificial lighting.
- **Natural Ventilation:** Incorporating operable windows and ventilation systems allows for fresh air circulation without relying solely on mechanical systems.
- **Solar Orientation:** Proper building orientation takes advantage of sunlight for heating in winter and minimizes heat gain in summer.
8. **Heat Recovery Systems:**
- **Heat Exchangers:** Implementing heat recovery systems captures waste heat from processes or exhaust air to preheat incoming air or water.
9. **Green Roofs and Cool Roofs:**
- **Green Roofs:** Planting vegetation on rooftops can provide insulation, absorb rainwater, and reduce the heat island effect.
- **Cool Roofs:** Reflective roofing materials or coatings reflect sunlight and absorb less heat, helping to maintain cooler indoor temperatures.
10. **Energy Audits and Monitoring:**
- Regular energy audits identify areas of inefficiency and provide recommendations for improvements.
- Installing energy monitoring systems allows real-time tracking of energy use, enabling prompt action if consumption exceeds expectations.
Implementing these engineering approaches in building design, construction, and retrofitting can lead to significant energy savings and contribute to sustainable and environmentally responsible practices.
2) a. Derive the equation for compressor and throttling device with the help of steady energy equation by stating all their assumptions.
Ans:
b.
3) a. What are the main components of a flat-plate collectors, explain the function of each.
Ans:
b. ) Calculate the annual energy output of the PV power plant which consist of 35 modules located at site having average daily global radiation of 4.3 kwh/m2 and average ambient temperature is 35⁰C. The specification of a PV module under the standard testing conditions are :
4) a. In the context of biomass gasification, what engineering strategies can be employed to optimize the syngas composition and improve its suitability for diverse energy applications?
Ans : Biomass gasification is a process that converts biomass feedstock (such as wood, agricultural residues, and organic waste) into a mixture of gases known as syngas (synthetic gas), which mainly consists of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and other trace components. Optimizing the syngas composition is crucial to make it suitable for various energy applications. Here are some engineering strategies that can be employed to achieve this:
1. **Biomass Selection and Preparation:**
- Choose appropriate biomass feedstock based on its composition and energy content.
- Properly size and preprocess the biomass to achieve consistent feedstock quality, size, and moisture content.
2. **Gasification Technology Selection:**
- Different gasification technologies, such as fixed-bed, fluidized-bed, and entrained-flow gasifiers, have varying effects on syngas composition. Choose a technology that aligns with the desired syngas composition.
3. **Controlled Gasification Conditions:**
- Adjust gasification temperature, pressure, and residence time to influence the syngas composition.
- Higher temperatures tend to favor hydrogen production, while lower temperatures may lead to higher tar formation.
4. **Air-to-Fuel Ratio Control:**
- Vary the air-to-fuel (or oxygen-to-fuel) ratio to achieve the desired balance between oxidation and reduction reactions.
- Adjusting this ratio can influence the ratios of CO to CO2 and H2 to CH4 in the syngas.
5. **Tar Removal and Cleanup:**
- Implement tar removal techniques such as scrubbing, filtration, and catalytic conversion to reduce the tar content in the syngas.
- Lower tar content improves the syngas quality for various applications and prevents equipment fouling.
6. **Catalytic Conversion:**
- Employ catalysts to enhance certain reactions within the gasifier, such as tar cracking and water-gas shift reactions.
- Catalysts can improve the yield of desired syngas components.
7. **Gas Cooling and Cleaning:**
- Rapidly cool the syngas after gasification to prevent undesirable reactions and condensation.
- Use cyclones, scrubbers, and filters to remove particulates and impurities from the syngas.
8. **Gas Composition Monitoring and Control:**
- Implement real-time monitoring and control systems to maintain consistent and desired syngas composition.
- Automated systems can adjust parameters based on variations in feedstock, temperature, or other factors.
9. **Syngas Utilization Technology:**
- Select appropriate utilization technologies such as internal combustion engines, gas turbines, fuel cells, and chemical synthesis processes based on the syngas composition and energy application.
10. **Feedstock Blending:**
- Blend different biomass feedstocks to achieve a more consistent and desirable syngas composition.
- Blending can help balance the limitations and advantages of various feedstocks.
11. **Syngas Conditioning:**
- Tailor the syngas composition for specific applications through conditioning processes like CO2 removal, shift reactions, and gas separation techniques.
b.
5 a. What are the primary factors that influence the origin and formation of winds in different regionsof the Earth?"
Ans : Winds are the result of air movement from areas of high pressure to areas of low pressure in the Earth's atmosphere. The primary factors that influence the origin and formation of winds in different regions of the Earth include:
1. **Pressure Gradients:** The difference in air pressure between two locations is the driving force behind wind. Air naturally moves from high-pressure areas to low-pressure areas, creating wind. The steeper the pressure gradient, the stronger the wind will be.
2. **Coriolis Effect:** The rotation of the Earth causes moving air to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This phenomenon is known as the Coriolis effect. It influences the direction of wind flow and contributes to the formation of global wind patterns.
3. **Temperature Differences:** Temperature variations across the Earth's surface create pressure differences due to the different densities of warm and cold air. Warm air rises, creating a low-pressure area, while cool air sinks, creating a high-pressure area. These temperature-driven pressure differences influence wind circulation.
4. **Global Circulation Patterns:**
- **Hadley Cells:** At the equator, warm air rises due to intense solar heating. This creates a low-pressure area, and air moves poleward in the upper atmosphere. As it cools, it sinks at around 30 degrees latitude in both hemispheres, creating high-pressure subtropical zones.
- **Ferrel Cells and Polar Cells:** These cells are intermediate and polar circulation cells that interact with the Hadley cells to create the overall pattern of global circulation. They contribute to the formation of prevailing wind belts.
5. **Monsoons:** Monsoons are seasonal wind patterns influenced by temperature differences between land and ocean. During the summer, the land heats up more quickly than the ocean, creating a low-pressure area that draws moist air from the ocean, causing rainy seasons. In the winter, the process reverses.
6. **Ocean Currents:** Ocean currents can influence wind patterns by affecting temperature and moisture levels over large areas. Warm ocean currents can transfer heat to the atmosphere, affecting pressure and wind systems.
7. **Topography:** Mountains, valleys, and other geographical features can influence local wind patterns. For example, wind can be channeled through mountain passes, creating localized patterns such as the "katabatic" winds that flow down slopes.
8. **Seasonal Changes:** The tilt of the Earth's axis causes the changing seasons, which in turn affect temperature differences and pressure systems. This leads to shifts in wind patterns, particularly in mid-latitudes.
9. **Land-Sea Contrasts:** Land heats and cools faster than water. This creates temperature differences that lead to onshore and offshore breezes, as well as daytime and nighttime wind shifts.
10. **Local Effects:** Urban areas can create their own microclimates and wind patterns due to changes in surface properties like asphalt, buildings, and vegetation.
11. **Weather Systems:** The movement and interaction of weather systems, such as low-pressure cyclones and high-pressure anticyclones, can influence wind patterns and their directions.
OR
Discuss the feasibility of implementing small and micro-hydropower projects in remote areas of Nepal and the engineering strategies to overcome logistical and technical challenges.
Ans : Implementing small and micro-hydropower projects in remote areas of Nepal can have significant benefits, including providing clean and reliable electricity to communities that are often far from the main power grid. However, there are both logistical and technical challenges that need to be addressed to make these projects feasible and successful. Here's a discussion of the feasibility and potential engineering strategies to overcome challenges:
**Feasibility:**
1. **Resource Availability:** Nepal is rich in water resources due to its hilly and mountainous terrain, making it well-suited for small hydropower projects.
2. **Energy Demand:** Many remote areas lack access to electricity, creating a demand for decentralized power sources like small hydropower.
3. **Local Benefits:** Hydropower projects can stimulate local economies, create jobs, and improve living standards in remote communities.
**Logistical Challenges:**
1. **Inaccessible Locations:** Remote areas often lack proper road infrastructure, making transportation of equipment and materials challenging.
2. **Limited Skilled Labor:** Finding skilled workers in remote areas might be difficult, requiring training and capacity building.
3. **Permitting and Regulatory Issues:** Remote areas might have less developed regulatory frameworks and longer permit processes.
**Engineering Strategies:**
1. **Site Selection:** Choose suitable sites for hydropower projects based on water availability, topography, and accessibility. Conduct thorough feasibility studies and site assessments to ensure the project's viability.
2. **Design Adaptation:** Opt for run-of-the-river designs that minimize the need for large dams and reservoirs, reducing environmental impact and infrastructure requirements.
3. **Modular Approaches:** Consider modular designs that allow for incremental capacity expansion. This can help in managing project complexity and initial costs.
4. **Local Workforce Development:** Train local residents in construction, operation, and maintenance of the hydropower system. This not only empowers the community but also ensures long-term sustainability.
5. **Transportation Solutions:** Develop innovative transportation methods, such as using helicopters, cable cars, or mules to transport equipment and materials to remote sites.
6. **Remote Sensing and Communication:** Use remote sensing technology for site assessment and monitoring. Establish efficient communication networks to manage operations and maintenance remotely.
7. **Prefabrication and Standardization:** Prefabricate components off-site to minimize on-site construction time and reduce the need for extensive tooling and skilled labor.
8. **Collaboration and Local Partnerships:** Collaborate with local communities, government agencies, and non-governmental organizations to ensure community involvement, access to resources, and proper land-use management.
9. **Off-Grid Solutions:** Implement microgrid systems that combine hydropower with energy storage (batteries) to provide consistent power even during low water flow periods.
10. **Environmental Considerations:** Conduct thorough environmental impact assessments and implement mitigation measures to minimize disruption to local ecosystems and water bodies.
11. **Capacity Building:** Work with local institutions and organizations to provide training in project management, technical skills, and business development related to hydropower.
Implementing small and micro-hydropower projects in remote areas of Nepal requires a holistic approach that considers local needs, environmental sustainability, and the specific challenges of the region. By addressing logistical and technical challenges through innovative engineering strategies, these projects can have a positive impact on the lives of people in remote communities while promoting sustainable development.
b.What is the required diameter (in meters) of the wind turbine rotor needed to generate a combinedelectrical power of 1000 kW from seven wind turbines operating at an efficiency of 51%? Thewind speed at hub height is a constant 25 Km/hr, and the surrounding air's average temperatureand pressure are 18°C and 2.02 bar, respectively.
6 a.What is cross ventilation and how can it be achieved in buildings? Give examples.
Ans:**Cross Ventilation** is a natural ventilation strategy used in buildings to promote the flow of fresh air through indoor spaces by creating pressure differences between openings on opposite sides of the building. It relies on wind and temperature differences to drive air movement, helping to maintain comfortable indoor conditions and improve indoor air quality. Cross ventilation is especially effective in climates where wind patterns are consistent and temperatures vary between day and night.
Achieving cross ventilation involves strategic placement of openings (windows, doors, vents) to allow air to enter from one side of the building and exit from the opposite side. Here are some methods to achieve cross ventilation in buildings:
1. **Window Placement:** Position windows on opposite sides of a room or building to create a direct pathway for air to flow through. Ideally, windows should be aligned along the prevailing wind direction.
2. **Building Orientation:** Align the longer sides of the building with the prevailing wind direction to maximize the potential for cross ventilation.
3. **Size and Location:** Design windows and openings to be larger on the windward side (where the wind is coming from) and smaller on the leeward side (opposite to the wind direction). This helps create pressure differences that drive air movement.
4. **Interior Layout:** Plan the interior layout to allow for unobstructed air movement between openings. Avoid placing furniture or objects that could block the airflow.
5. **Stack Effect:** Utilize the stack effect, which occurs due to temperature differences between indoor and outdoor air. Warm air rises and escapes through high openings, drawing in cooler air from lower openings.
6. **Atriums and Courtyards:** Design central courtyards or atriums with openings on opposite sides. This creates a natural airflow pathway through the building's core.
7. **Operable Vents and Louvers:** Install adjustable vents, louvers, or dampers that can be opened or closed to control air intake and exhaust. These are particularly useful for regulating airflow in different weather conditions.
8. **Wind Scoops:** Wind scoops or wind-catchers are architectural features designed to catch and direct prevailing winds into a building. They can enhance cross ventilation, especially in hot and arid regions.
Examples of Cross Ventilation in Buildings:
1. **Traditional Vernacular Architecture:** Many traditional buildings in hot and humid climates, such as the windcatchers of Iran or the "venturi effect" towers in Rajasthan, India, employ cross ventilation techniques to cool indoor spaces.
2. **Modern Residential Buildings:** Houses and apartments with windows on opposing sides can achieve cross ventilation by opening windows to create airflow paths.
3. **Educational Institutions:** Schools and universities often incorporate cross ventilation strategies to maintain fresh indoor air and comfort for occupants.
4. **Commercial Buildings:** Offices and commercial spaces use well-placed windows and openings to facilitate natural air movement and reduce reliance on mechanical ventilation.
5. **Hospitals and Healthcare Facilities:** Maintaining good indoor air quality is crucial in healthcare settings. Cross ventilation can help prevent the buildup of pollutants and improve patient comfort.
Cross ventilation is a sustainable and energy-efficient way to enhance indoor air quality and thermal comfort without relying heavily on mechanical ventilation systems. Its success relies on careful design, taking into account local climate conditions, wind patterns, and building layout.
OR
What do you mean by thermal comfort based on ASHRAE standard? Clarify the factors that signify thermal comfort?
Ans :Thermal comfort, as defined by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), refers to the condition of mind that expresses satisfaction with the thermal environment. In simpler terms, it's when individuals feel comfortable and content with the temperature and other environmental factors surrounding them. ASHRAE provides standards and guidelines to help define and achieve thermal comfort in various indoor environments.
Factors that Signify Thermal Comfort (Based on ASHRAE Standard 55-2020):
ASHRAE Standard 55 defines six primary factors that contribute to thermal comfort:
1. **Air Temperature:** This is the most obvious factor. A comfortable air temperature is one that does not feel too hot or too cold for the majority of people in a given space.
2. **Radiant Temperature:** Radiant temperature is the average temperature of all surfaces that emit heat energy toward a person's body. This includes walls, floors, ceilings, and other objects. Perceived comfort can be affected by the warmth or coolness of these surfaces.
3. **Air Velocity:** The movement of air affects how our body perceives temperature. Even in a warm environment, a gentle breeze can make us feel cooler by enhancing the evaporative cooling effect of our skin.
4. **Relative Humidity:** Humidity levels influence how our bodies regulate temperature through sweating. High humidity can hinder the body's ability to cool itself, while low humidity can lead to discomfort and dryness.
5. **Clothing Insulation:** The type and amount of clothing worn impact how the body interacts with the environment. People dressed in heavy clothing may feel warm even in a relatively cool room, while those in light clothing may feel comfortable at a higher temperature.
6. **Metabolic Rate:** This factor considers the level of physical activity a person is engaged in. More active individuals generate more heat and may feel comfortable at slightly lower temperatures.
ASHRAE Standard 55 also recognizes additional variables that can influence thermal comfort:
- **Personal Factors:** These include factors such as age, gender, individual metabolic rates, and personal preferences. What's comfortable for one person may not be comfortable for another.
- **Adaptive Comfort:** This concept suggests that people can adapt to a wider range of thermal conditions over time if given some level of control. For example, someone may find a lower temperature comfortable if they have access to warmer clothing.
- **Local Discomfort:** Certain localized conditions, such as drafts or radiant heat from nearby equipment, can affect thermal comfort even when the overall room conditions are acceptable.
It's important to note that achieving universal thermal comfort for all occupants can be challenging due to individual differences and preferences. However, by considering the factors outlined by ASHRAE and designing indoor environments that allow some level of personal control, designers and facility managers can create spaces where the majority of occupants feel comfortable.
b. Moist air exists at 60°C dry-bulb temperature, 30°C thermodynamic wet-bulb temperature, and101.325 kPa pressure. Determine the humidity ratio, enthalpy, dew-point temperature, relativehumidity, and specific volume.
7) Write short notes: (Answer any two)
a) Green Hydrogen:
Green hydrogen refers to hydrogen gas produced through a process called electrolysis, where water is split into hydrogen and oxygen using electricity. The electricity used in this process is generated from renewable sources such as solar, wind, or hydropower, making the production process emissions-free. Green hydrogen is considered a clean and sustainable energy carrier as it can be used in various applications, including industrial processes, transportation, and energy storage. It holds great potential for reducing carbon emissions and supporting the transition to a low-carbon energy system.
b) Indicators of Global Climate Change:
Global climate change is driven by various indicators that demonstrate shifts in Earth's climate patterns. Some key indicators include:
- **Temperature Rise:** Rising average global temperatures over time, leading to shifts in climate zones and weather patterns.
- **Sea Level Rise:** Increasing sea levels due to the melting of glaciers and thermal expansion of seawater.
- **Extreme Weather Events:** More frequent and intense events like hurricanes, heatwaves, and heavy rainfall due to changing climate conditions.
- **Glacial Retreat:** Decrease in the size of glaciers worldwide due to warming temperatures.
- **Ocean Acidification:** Increasing acidity of oceans due to higher carbon dioxide levels in the atmosphere.
- **Arctic Sea Ice Decline:** Reduction in Arctic sea ice extent and thickness due to warmer temperatures.
- **Species Migration:** Species shifting their habitats to cooler areas in response to changing temperatures.
- **Coral Bleaching:** Discoloration of coral reefs due to stress from higher sea temperatures.
c) Mechanical Energy Storage System:
Mechanical energy storage systems store energy in the form of mechanical potential or kinetic energy, which can be later converted back into electricity when needed. Examples include:
- **Pumped Hydro Storage:** Water is pumped uphill during periods of low demand and released downhill through turbines to generate electricity during peak demand.
- **Flywheels:** Rotating mechanical devices that store energy in the form of rotational kinetic energy. The energy can be released by decelerating the flywheel.
- **Compressed Air Energy Storage (CAES):** Air is compressed and stored in underground caverns or tanks. The compressed air is then released and expanded through turbines to generate electricity.
- **Gravitational Energy Storage:** Objects are lifted to a higher position using excess energy and lowered to release stored energy when needed.
These mechanical energy storage systems contribute to grid stability, enabling the integration of renewable energy sources by storing excess energy and supplying it during periods of high demand or low renewable output.
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