The temperature in an unconditioned mechanical room is found to typically be around 23°C warmer than ambient air. If the air intake of an air compressor located in the mechanical room is routed through a nearby wall so that ambient air is fed directly to the air compressor's intake, what impact can be expected on the air compressor's energy requirement?

What is the definition of lamp life for a fluorescent lamp?

Using the natural gas combustion efficiency tables in your workbook, find the combustion efficiency (based on higher-heating value) of a natural-gas-fired boiler if the excess air level is measured at 31.9% and the stack temperature rise is 187.8°C.

Which of the following statements best describe Demand Control Ventilation (DVC) in Building Automation Systems?

A 50-kW induction motor (1,500 rpm synchronous speed) has a nameplate full-load rotational speed of 1,455 rpm. Field measurements show the actual rotational speed is 1,475 rpm. Using the slip method, calculate the partial load factor of the motor.

Exhaust gases from an industrial furnace flow through a heat-recovery steam generator, which generates medium-pressure steam. This steam is used in a steam turbine to generate shaft power driving a fan. Which type of combined heat and power (CHP) cycle does this process describe?

At the end of a performance contract, who owns the equipment installed by the project?

A gas-fired boiler is operating with 31.9% excess air. A feedwater economizer is used to reduce the stack temperature rise from 310°C to 160°C. Using the natural gas combustion efficiency tables in your workbook, find the energy savings from the economizer as a percentage of historical fuel consumption.

A 75-kW induction motor operates at 80% partial load and 88% efficiency. A new high-efficiency 75-kW motor can be installed that will operate at 95% efficiency (also at 80% partial load). What is the reduction in electric power demand?

Which is the best application for variable-speed drives?

What is a common cause of poor power quality?

Using the lumen method, calculate the number of luminaires (fixtures) required to light a room to 200 lux. Each luminaire has 2 fluorescent lamps, 3,000 lumens per lamp. The room is 20 meters by 30 meters. The total light loss factor (LLF) is 0.70 and the luminaire coefficient of utilization (CU) is 0.80.

Natural gas costs $4.80/GJ. How much does it cost to heat 500 liters of water from 18°C to 50°C using a natural gas water heater with an efficiency of 85%? [The efficiency and fuel price are both based on HHV. The specific heat of water (C) is 4.2 kJ/kg-°C.]

How can you tell if steam traps in a steam distribution system may NOT be working correctly?

If the initial design process includes group relamping, how can this reduce the number of lamps required to illuminate a space?

A 55-kW motor at full load is used to drive a pump that generates 50 meters of head while pumping water at a rate of 5,000 liters per minute. Calculate the pump efficiency.

A cooling tower is delivering water to a chilled-water plant. The cooling tower outlet temperature has a 6°C approach temperature to the ambient air, wet-bulb temperature. The outside air conditions are 20°C dry bulb, 60% relative humidity. Using the psychrometric chart, at what temperature can the cooling tower deliver water to the chilled-water plant?

What is the main reason for using instrumentation in energy audits?

What is the best type of heat exchanger to recover and transfer latent heat energy from one air stream to another?

Some international electric utilities use 'net metering" for customers with renewable energy equipment, such as photovoltaic power panels. Which of the following best describes net metering with regard to excess power generation and utility billing practices?

SELECT THE CORRECT ANSWER

Which problems can be caused by poor power quality?

How can commissioning reduce the life-cycle cost to owners and operators?

Which of the following is NOT a renewable-energy resource?

SELECT THE CORRECT ANSWER

What is the purpose of monitoring energy consumption?

SELECT THE CORRECT ANSWER

Which of the following is/are benefits of commissioning?

You can buy air compressor A for $15,000 or air compressor B for $6,000. Compressor A will cost $10,000 per year to operate. Compressor B will cost $11,500 per year to operate. If both air compressors have a 10-year life and your required return on investment is 12%, which air compressor has the lowest total life-cycle cost?

Which type of lighting control technique operates in "manual on" and "auto-off mode, and can be used in situations where there is brief occupancy that do not need lights on?

Electricity costs SO. 10 per kWh. if an electric water heater has an efficiency of 95*6. what is the equivalent price of natural gas per Gigajoule for a natural gas water heater? The natural gas water heater has an efficiency of 95*t based on lower-heating value.

[Natural gas has an energy content of 36.400 K|/m3 (higher-heating value) and 32-760 K/m3 (lower-heating value).]

SELECT THE CORRECT ANSWER

In a performance contract, which group has the greatest investment risk?

Which of the following steam turbines will likely not provide steam output at a useable temperature for industrial processes?

How does an enthalpy-based economizer control operate?

Which pump system listed below is most likely the best application for converting to variable-speed drive?

A 1OO-kW packaged engine-generate combined heat and power (CHP) system has the specifications listed below. The CHP equipment operates fully loaded for 8.000 h/yr. What isthe annual fuel cost for the ChP equipment?

CMP equipment specifications: Electrical output 100kw Electrical efficiency: 25% Thermal recovery efficiency: 50*6 Total CMP efficiency: 75%

Additional information: Fuel cost: S3.S0/GJ Electricity cost S0.06/kWh Previous water heating efficiency: 8046 Mot water usage: 75,700 liters/day (21 *C temperature rise)

[The question from the previous image, which was about calculating the annual cost of heat loss through a wall, but had a discrepancy between the calculated cost and the provided answer choices]

What term describes the difference between the control signal value and the set point?

A desk lamp is located inside a windowless office. The office is heated during the winter and cooled during the summer. When the lamp is switched on, how much of the energy consumed by the lamp becomes heat in the office space?

A new energy-efficient boiler costs $60,890 to buy and install. The new energy-efficient boiler will save $15,400 per year and last for 20 years. What is the internal rate of return (IRR) of the project?