Machinery Flashcards by Herbert Acosta

What is Renewable Energy Engineering?

A discipline that deals with the production of energy from renewable or sustainable sources including wind, solar, hydro, biomass, geothermal, and ocean energy.

Renewable energy sources are critical for sustainable development and reducing reliance on fossil fuels.

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Define Bioenergy Engineering.

A branch of science focused on the conversion of biomass, including wastes, into useful fuel and other products through various processes.

Biomass can potentially replace fossil fuels due to its energy density.

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List the renewable energy sources highlighted in agriculture and fishery.

Biomass
Solar
Wind
Hydro

These sources can be converted into thermal, mechanical, or electrical power.

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What is one major benefit of renewable energy?

It is environment-friendly and reduces greenhouse gas emissions.

Renewable energy contributes to mitigating climate change.

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What is the Renewable Energy Act?

Republic Act 9513, enacted on July 28, 2008, promotes the development, utilization, and commercialization of renewable energy sources.

This law aims to enhance energy security and sustainability.

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What is the purpose of the Biofuel Act?

To promote the development and usage of biofuels in the Philippines to reduce dependence on imported fuels while protecting public health and the environment.

The Biofuel Act was enacted on January 12, 2007.

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True or False: Renewable energy sources are depleting.

False.

Renewable energy sources are naturally available and cannot be depleted.

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What are the two types of heating values of fuel?

Higher Heating Value (HHV)
Lower Heating Value (LHV)

HHV accounts for the heat from condensing water vapor, while LHV does not.

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Fill in the blank: A __________ is a facility that produces electrical and/or mechanical energy as well as useful thermal energy.

Co-Generation System.

Co-generation systems are efficient as they utilize the heat produced during electricity generation.

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What is a Hybrid System?

A power generation facility that uses two or more technologies utilizing both conventional and renewable fuel sources.

Hybrid systems can enhance energy efficiency and reliability.

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What does the Feed-In Tariff (FIT) support?

It supports the development of renewable energy sources by providing a guaranteed price for producers.

FIT encourages investment in renewable energy technologies.

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Define Distributed Generation System.

Small generation entities directly supplying electricity to the distribution grid, not exceeding 100kW in capacity.

Distributed generation enhances energy resilience and local energy production.

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List the characteristics of Biomass energy.

Produces thermal, mechanical, and electrical energy
Moderately location specific
Medium investment cost
Moderate maintenance requirement
Medium operating cost

Biomass energy is derived from organic materials and is versatile in applications.

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What is the primary power produced by Solar Thermal energy?

Thermal power.

Solar thermal systems capture and utilize the sun’s heat for various applications.

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What principle does a Wind Turbine operate on?

It converts the kinetic energy of wind into electricity.

Wind turbines can vary in design, with horizontal and vertical axes being common.

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Fill in the blank: __________ is energy from flowing water captured through turbines.

Hydro energy.

Hydro energy is one of the most widely used renewable energy sources worldwide.

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What is the significance of the Agriculture and Fisheries Mechanization Law?

It aims to improve the agriculture and fisheries sector through mechanization.

This law covers research, development, and promotion of agricultural machinery.

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What is the function of devices like rotating wheels and pumps?

To rotate producing rotary or reciprocating motion to produce power

Devices include transmission drives and spiral pipes.

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What is the act regulating the practice of agricultural engineering in the Philippines?

Republic Act No. 8559

Other relevant acts include Republic Act No. 9513 and Republic Act No. 8749.

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What is a renewable energy facility?

A facility for the production of electricity and/or thermal energy.

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Which of the following is not considered biomass?

Coal

Biomass includes rice husk, wood, and sugar bagasse.

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What is a co-generation system?

A facility that produces electrical and/or mechanical energy and useful thermal energy.

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Which of the following is a renewable energy source?

All of the above

Includes biomass, solar, wind, hydro, geothermal, and ocean.

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Which of the following is a non-renewable fuel?

All of the above

Includes crude oil, natural gas, and coal.

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What is net metering?

A system appropriate for distributed generation with a two-way connection to the grid.

What is a Power Application Facility?

A renewable energy system or facility that produces electricity.

What does the term 'grid' refer to?

High voltage backbone system of interconnected transmission lines.

What is a Non-Power Application Facility?

A renewable energy system or facility that produces mechanical energy or thermal energy not used for electricity generation.

What is a co-generation system?

A facility that utilizes two or more types of technologies, both conventional and renewable.

What is a conventional energy source?

An energy source that is commonly used, like crude oil.

Fill in the blank: 1 Joule is equivalent to _______.

1 N-m

What is the feed-in tariff rate for solar power?

P9.68 per kW-hr ## Footnote Other rates include P8.53 per kW-hr, P5.80 per kW-hr, and P6.63 per kW-hr.

What type of air is used directly in the combustion of fuel?

Primary air

What is the feed-in tariff for biomass power?

P9.68 per kW-hr ## Footnote Other rates include P8.53 per kW-hr, P5.80 per kW-hr, and P6.63 per kW-hr.

What type of air is used to further burn the gases derived during combustion?

Secondary air

What percentage of total energy demanded by a single household in the Philippines is from biomass?

32% ## Footnote This statistic highlights the reliance on biomass as a significant energy source for cooking.

What is a biomass stove?

A solid-biomass-burning device producing heat for domestic cooking ## Footnote It uses fuel wood and charcoal.

Define 'Improved Stove'.

A solid-biomass-fuel burning system used for varied applications such as cooking and heating.

What does 'Biomass Fuel' refer to?

Solid biomass in raw or processed form, including fuelwood and agri-residues.

What is combustion?

The process through which fuel and air chemically interact at elevated temperatures.

What is heat transfer?

The process by which heat generated from combustion is transferred to a heat-absorbing surface.

What does fluid flow refer to?

The movement of fluids like air and gas through a medium under pressure.

What is meant by 'Material Science' in the context of stove construction?

Selection and utilization of materials for durability, cost, safety, and heat loss considerations.

What is the temperature range for frying?

Between 200° and 300°C.

What characterizes a Multi-Function Stove?

Can be used for several applications such as broiling, steaming, and grilling.

What is a Mono Function stove?

A stove that can be used for one purpose only.

What materials can a Metal Stove be made from?

Surplus steel material or prefabricated by casting metal.

What is a Fixed Stove?

A large, heavy stove with several burners and one fire box.

What does 'Granular Agri-waste Stove' use as fuel?

Husks, pods, and shells.

Fill in the blank: The heating value of Rice Husk is _______.

13.24-13.36 MJ/kg.

What is the efficiency range of an Improved Wood Stove?

11 – 30%.

What is the primary function of a damper in a stove?

To control the flow passage of air supply.

What factors influence combustion?

* Fuel * Air * Heat.

True or False: A higher heating value of fuel results in more power from the stove.

True.

What is the recommended excess air ratio for complete combustion?

1.5 to 2.0.

What is the effect of moisture content on fuel combustion?

Dry biomass burns better than wet biomass.

What is the recommended gap for baffles in stove design?

Between 35 to 70 mm.

What is the purpose of a chimney in a stove?

To discharge flue gases and create suction of air for combustion.

Fill in the blank: The firebox must be large enough to accommodate the amount and type of _______.

fuel.

What is the design of the front damper in a stove intended for?

To focus air at the base of the fire.

What is the purpose of the back damper in a stove?

To control air flow by reducing the draft from the chimney.

Where should baffles be placed in relation to pots in a stove?

Under all pots, not over the firebox.

What is the recommended gap for baffles to maintain adequate draft?

Between 35 to 70 mm.

What is the average suggested velocity for a chimney?

Ranges from 0.4 to 1 liter per second.

How far should a chimney extend above the highest point of the roof?

75 cm.

What is the formula for design power (Pd) in a stove?

Pd = 0.70 (Pc + Pv).

What does Pc represent in the design power formula?

Fuel power, kcal/hr.

What does Pv represent in the design power formula?

Volatile power, kcal/hr.

Convert 1 kW to kcal/hr.

1 kW = 0.860 kCal/hr.

What is the formula for average power output (Pave)?

Pave = SFC x HFV / Tb.

In the average power output formula, what does SFC stand for?

Summation of fuel charges, kg.

What is the net calorific value of rice hull?

3000 kcal/kg.

What is the formula for maximum power (Pmax) in cooking?

Pmax = Mf x Cf x (Tf – Ti) / (tc x 3s).

What does Mf represent in the maximum power formula?

Mass of food, kg.

What does Cf represent in the maximum power formula?

Specific heat of food, kCal/kg-°C.

What is the formula for the area of the fuel bed (Afb)?

Afb = Pd / Dp.

What does Dp represent in the fuel bed area formula?

Power density, kW/m2.

What is the formula for volumetric air flow rate (V)?

V = 29.7 x A x h½ x (1 – Ta/Tfb)½.

What does Ta represent in the volumetric air flow rate formula?

Air temperature, °C.

What does Tfb represent in the volumetric air flow rate formula?

Fuel bed temperature, °C.

What is the formula for fuel bed height (Hfb)?

Hfb = Fc / (p x df x Afb).

What is the thermal efficiency of a stove with a specific draft of 1 cm per m depth?

Assumed to be 25%.

What does Hf represent in the flame height formula?

Flame height, mm.

What is the formula for cooking time (Tc)?

Tc = 550 x Mf^0.38.

What is the formula for fuel consumption rate (FCR)?

FCR = Wf / Ot.

What is the formula for power density (Dp)?

Dp = FCR / Ag.

What factors affect stove performance?

* Behavior of cook * Variety of cooking tasks * Variation of fuel.

What is the overall efficiency formula?

ηo = (m cp (Tf – Ti) + We Hfg) / (Wf x HVF) x 100.

What does We represent in the overall efficiency formula?

Weight of water evaporated, kg.

What is the heating value of fuel used in the cocopeat-pellet stove example?

4,750 kcal/kg.

Calculate the thermal efficiency (ξs) of a stove.

ξs = (Qt x 100) / Qf.

What is the formula for power input (Pi)?

Pi = 0.0012 kWt/kcal/hr x FCR x HVF.

What is the formula for power output (Po)?

Po = Pi x thermal efficiency.

What is the effect of cooking time on stove performance?

It influences the overall energy efficiency and fuel consumption.

True or False: The design power of a stove is influenced by the type of fuel used.

True.

What is the calorific value range of biomass fuel?

Less than 5,000 kcal/kg, 5,000 to 10,000 kcal/kg, 10,000 to 15,000 kcal/kg ## Footnote Biomass generally has lower calorific values compared to other fuels.

What is the thermal efficiency range of an open-fire stove?

3-11%, 11-20%, 20-30% ## Footnote Open-fire stoves are typically less efficient than modern cookstoves.

What type of device burns solid biomass fuel for domestic use?

Cookstove ## Footnote Cookstoves are specifically designed for household cooking and heating.

What is the thermal efficiency of a rice husk stove that boils 2 liters of water and evaporates 0.5 liters using 1.5 kg of fuel?

5.2%, 9.2%, 12.5% ## Footnote This calculation involves the heat of vaporization and the heating value of the fuel.

What is the term for the part of a stove where fuel combustion takes place?

Firebox ## Footnote The firebox is crucial for the efficiency and safety of the stove.

What is the recommended angle for the inclined metal grate in a step-grate-type stove?

45-60 degrees ## Footnote Proper angling aids in fuel combustion and heat transfer.

If a biomass stove has a thermal efficiency of 15% and uses wood with a heating value of 4,000 kcal/kg, what is the consumption of wood per hour?

1.6 kg per hour, 2.0 kg per hour, 2.4 kg per hour ## Footnote This calculation is important for understanding fuel efficiency in biomass stoves.

What indicates the amount of fuel converted into ash in a direct stove?

Burning efficiency ## Footnote Understanding burning efficiency helps in optimizing fuel usage.

What is solid carbonaceous material derived from living plant matter called?

Biomass fuel ## Footnote Biomass is a renewable energy source derived from organic materials.

What is the percentage of primary air requirement for combustion of fuel in cookstoves based on total air?

80%, 60%, 40% ## Footnote Adequate air supply is essential for efficient combustion.

How can the thermal efficiency of cookstoves be increased?

Increasing the amount of fuel, using more air for the fuel, insulating the stove ## Footnote Improving thermal efficiency reduces fuel consumption and emissions.

What is the purpose of providing a damper in an agriwaste-fired multiple-burner stove?

To control the flow of air ## Footnote Controlling air flow optimizes combustion and efficiency.

What is the heat energy content of coconut shell charcoal in BTU/lb?

14223 BTU/lb ## Footnote This value is crucial for calculating energy content in cooking applications.

How many kilo calories are there in 10 kilos of coconut shell charcoal with a heat energy content of 14223 BTU/lb?

78,852.3 Kcal, 68,852.3 Kcal, 87,852.3 Kcal ## Footnote Converting BTU to kcal is important for understanding energy use.

What are fuel blocks produced through simple compaction of biomass called?

Densified briquettes ## Footnote These briquettes provide a convenient and efficient fuel source.