Questions and Answers of Mechanical And Electrical Systems In Architecture Engineering And Construction

What is a wind energy conversion system?
How does elevation of a wind turbine affect turbine output?
Describe the following wind systems:a. Stand alone off gridb. Grid connected
What is Betz’s limit?
Selecting the best-suited HVAC system depends on factors such as: cost and availability of the energy source; appliance or system efficiency; cost to purchase, install, and maintain the appliance or
A photovoltaic (PV) system is being considered for a building with a load of 8 kW. The PV system will be approximately 16% efficient. Approximate the PV array size (in ft2) required to meet this load
A PV system is being considered for a building with a load of 10 kW. The PV system will be approximately 14% efficient. Approximate the PV array size (in ft2) required to meet this load at the
A PV system is being considered for a building with a load of 8 kW. The PV system will be approximately 16% efficient. Approximate the PV array size (in ft2) required to meet this load at the
A PV system is being considered for a building with a load of 6 kW. The PV system will be approximately 18% efficient. Approximate the PV array size (in ft2) required to meet this load at the
The known mean wind velocity is 13.2 mph at a site at a height of 33 ft (about 10 m). Approximate the wind velocity at a height of 100 ft (about 30 m) for the following sites:a. Site located in
The known mean wind velocity is 15.3 mph at a site at a height of 33 ft (about 10 m). Approximate the wind velocity at a height of 100 ft (about 30 m) for the following sites:a. Site located in
Approximate the theoretical power in wind moving at a speed of 7 m/s with an air temperature of 4°C striking a wind turbine with the following rotor sizes at a site at sea level:a. 2 mb. 4 mc. 6 md.
Approximate the theoretical power in wind moving at a speed of 14 mph with an air temperature of 40°F striking wind turbine with the following rotor sizes at a site at sea level:a. 10 ftb. 15 ftc.
Approximate the theoretical power in the wind at a site at sea level with an air temperature of 50°F striking a wind turbine with a 15 ft rotor size at the following wind velocities:a. 10 mphb. 15
A horizontal axis wind turbine has a rotor diameter of 24 ft. The turbine coefficient of performance is 0.37, generator efficiency is 0.78, and gearbox transmission efficiency is 0.94. Air is at a
A horizontal axis wind turbine has a rotor diameter of 24 ft. The turbine coefficient of performance is 0.37, generator efficiency is 0.80, and gearbox transmission efficiency is 0.94. Air is at a
Selecting the best-suited HVAC system depends on factors such as: cost and availability of the energy source; appliance or system efficiency; cost to purchase, install, and maintain the appliance or
With respect to a rainwater harvesting system, explain first-flush washing.
Describe a rainwater collection/harvesting systems.
Explain the components of a run-of-the-river hydropower system.
What is a hydropower system?
Describe the types of ventilation equipment.
Describe humidification and why is it needed in buildings.
Describe dehumidification and why is it needed in buildings.
Describe heat recovery ventilation.
Describe how cogeneration can be used in an HVAC system.
Describe district heating and district cooling.
The cooling load of a residence at summer design conditions is 46 800 Btu/hr. From the performance specifications for high-efficiency residential central air conditioners provided in Table 6.8,
In a commercial building, the heating load at winter design conditions is 211 400 Btu/hr (with pick-up allowance) and the cooling load at summer design conditions is 232 800 Btu/hr. From the
A school district is considering heating systems for a high school anticipated to have an annual heating load of 6200 MMBtu/year. Compute the annual cost of heating the building with these systems:a.
A school district is considering heating systems for a high school anticipated to have an annual heating load of 7200 GJ/year. Compute the annual cost of heating the building with these systems:a. A
Describe the following air distribution components:a. Ductworkb. Duct insulationc. Damperd. Diffuserse. Grillesf. Fansg. Coils
What is an air-handling unit? Describe its chief components. Where is it used?
What is the difference between a roof-mounted airhandling unit (AHU) and an rooftop unit (RTU)?
Describe the purpose of a fan filter unit (FFU) and where it may be used.
Describe the purpose of a makeup air unit (MAU) and where it may be used.
Describe the function of the following types of ducts:a. Supply airb. Outdoor airc. Return aird. Mixed air
Describe the types of multiblade dampers.
Describe the purpose of installing smoke and fire dampers.
How are duct joints sealed?
Why are filters needed in an air distribution system?
Identify materials that can serve as a semipermeable VDR.
What is the difference between a nonpermeable VDR and a semipermeable VDR?
Why does bitumen-impregnated kraft paper work effectively as a VDR?
How can moisture problems associated with water intrusion be reduced?
How can moisture problems associated with vapor diffusion be reduced?
How can moisture problems associated with airborne water vapor infiltration be reduced?
A 64 000 ft2 warehouse is designed to store electronic equipment in a big box retail store. Determine the minimum outdoor air (ventilation) rate for this space, in cfm.
For the conditions in the previous exercise, describe a good strategy for use of a VDR.Data from previous Exercise A building has indoor air conditions of 70°F dry bulbtemperature and 40% relative
A 7000 m2 warehouse is designed to store electronic equipment in a big box retail store. Determine the minimum outdoor air (ventilation) rate for this space, in liters per second.
A restaurant has an 800 ft2 cocktail lounge and a 3800 ft2 dining room, which are served by a single rooftop HVAC unit. Determine the outdoor (ventilation) air requirements for this unit based upon
A restaurant has a 90 m2 cocktail lounge and a 420 m2 dining room, which are served by a single rooftop HVAC unit. Determine the outdoor (ventilation) air requirements for this unit based on the
A building has indoor air conditions of 70°F dry bulb temperature and 40% relative humidity. Determine the direction of water vapor flow under the following outdoor air conditions that represent a
A building has indoor air conditions of 70°F dry bulb temperature and 50% relative humidity. Determine the direction of water vapor flow under the following outdoor air conditions that represent a
For the conditions in the previous exercise, describe a good strategy for use of a VDR.Data From Previous Exercise:A building has indoor air conditions of 70°F dry bulb temperature and 50% relative
A building has indoor air conditions of 70°F dry bulb temperature and 40% relative humidity. Determine the direction of water vapor flow under the following outdoor air conditions that represent a
What is a building air barrier, and where and why is it used in a construction assembly?
Describe the airtight drywall alternative to a VDR.
What is an ice dam and how can it be prevented?
Describe a dynamic buffer zone (DBZ) ventilation system.
For single-family dwellings in Denver, Colorado, the International Energy Conservation Code (IECC) offers the following minimum R-value ranges for the construction assemblies shown (depending on
For multifamily dwellings in Denver, Colorado, the IECC requires the following minimum R-values for the construction assemblies shown. Convert these R-values to the metric equivalent thermal
For a three-story, 100 000 ft2 office building in Denver, Colorado, the IECC requires the following minimum R-values for the construction assemblies. Convert these R-values to the metric equivalent
For single-family dwellings in Denver, Colorado, the IECC requires window assemblies to have minimum U-factors in the range of 0.35 to 0.45 Btu/hr · °F · ft2. Convert these U-factors to:a. The
For multifamily dwellings in Denver, Colorado, the IECC requires window assemblies to have a minimum U-factor of 0.45 Btu/hr · °F · ft2. Convert this U-factor to:a. The thermal resistance
For a three-story, 100 000 ft2 office building in Denver, Colorado, the (IECC) requires window assemblies to have a minimum U-factor of 0.70 Btu/hr · °F · ft2 (for IECC climate zone 5). Convert
A conference room is designed with seating for 20 occupants. Determine the minimum outdoor air (ventilation) rate for this space, in cfm. A classroom is designed with seating for 32 occupants.
An auditorium-like lecture room is designed with seating for 300 occupants. Determine the minimum outdoor air (ventilation) rate for this space, in cfm, based on:a. International Mechanical Codeb.
The transmission heat load is computed by the equation, UA(ΔT). Describe each term in this equation.
With respect to a heating load, what is a pick-up allowance?
Air infiltration rates (i.e., air change per hour) vary considerably. Describe typical infiltration rates in new and older buildings.
How is the outside design temperature determined?
When are the following winter design conditions used?a. 99.6% dry bulb temperatureb. 99.0% dry bulb temperature
Find the outside design temperature for the geographical location at which you reside.
Describe the degree-day, and how it will affect the amount of fuel used per year.
How does seasonal efficiency of the heating system affect heating costs?
List some of the ways in which the heat loss of a building can be controlled.
Why is limiting of window area important in keeping the heat loss low?
Describe three methods used to estimate energy consumption.
Calculate the number of simple degree-days in a day if the high temperature were 40°F and the low temperature were 0°F.a. For a base temperature of 65°F.b. For a base temperature of 60°F.c. For a
Calculate the number of simple degree-days in a day if the high temperature were 10°C and the low temperature were 0°C.a. For a base temperature of 18°C.b. For a base temperature of 15°C.c. For a
Calculate the number of simple degree-days in a day if the high temperature were 70°F and the low temperature were 50°F.a. For a base temperature of 65°F.b. For a base temperature of 60°F.c. For
Calculate the number of degree-days in a 30-day month if every day had an average daily temperature of 30°F.a. For a base temperature of 65°F.b. For a base temperature of 60°F.c. For a base
Calculate the number of degree-days in a 30-day month if every day had an average daily temperature of 10°C.a. For a base temperature of 18°C.b. For a base temperature of 15°C.c. For a base
A building has a 9 ft deep basement (foundation) wall that is 160 ft long. The wall has no windows. On average, 8 ft of the wall is below grade (underground). Assume an outside air temperature of
A building has a 2.4 m deep basement (foundation) wall that is 100 m long. The wall has no windows. On average, 2.1 m of the wall is below grade (underground). Assume the outside air temperature is -
A commercial building is built on a slab on grade foundation that is a 120 ft by 48 ft rectangular shape. Assume the outside design temperature is 5°F. Determine the rate of heat loss through the
A commercial building is built on a slab on grade foundation that is a 40 m by 18 m rectangular shape. Assume the outside design temperature is 15°C. Determine the rate of heat loss through the
Calculate the rate of infiltration heat loss of a room with a 380 ft2 floor area and 10 ft high ceilings. Use an inside temperature of 72°F, an outside ambient temperature of -5°F. Assume the heat
Calculate the rate of infiltration heat loss of a room with a 42 m2 floor area and 4 m high ceilings. Use an inside temperature of 21°C and an outside ambient temperature of -15°C. Assume the heat
A college lecture auditorium is designed for an occupancy of 300 persons. The ASHRAE Standard calls for a minimum outside airflow rate for classrooms of 15 cfm per person. The target inside design
A college lecture auditorium is designed for an occupancy of 300 persons. The ASHRAE Standard calls for a minimum outside airflow rate for classrooms of 2 L/s per person. The target inside design
A building has a heat loss of 100 MBtu/hr at design conditions at the geographical location where you reside.Calculate fuel consumed over the heating season at the geographical location where you
For the office building in the preceding table, compute the following for 2006:a. Monthly natural gas consumption based on Btu/ft2 of floor area.b. Annual natural gas consumption based on Btu/ft2 of
A building has a heat loss of 100 MJ/hr at design conditions at the geographical location where you reside. Calculate fuel consumed over the heating season at the geographical location where you
For the office building in the preceding table, compute the following for 2007:a. Monthly natural gas consumption based on Btu/ft2 of floor area.b. Annual natural gas consumption based on Btu/ft2 of
Calculate the heat loss for the residence in Appendix D on a room-by-room basis. Assume the residence will be built at the geographical location where you reside.Residence in Appendix D 988 FRONT
Calculate the heat loss for a top-floor apartment and an apartment that is below the top floor, using the apartment building in Appendix A. Assume the apartment will be built at the geographical
Describe the factors that must be considered when determining heat gain in buildings.
Define sensible and latent heat.

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