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Question 1Energy Management

In a commercial building energy audit, which metric best expresses whole-facility annual energy consumption per unit of floor area across all fuel types?

  1. Site energy use intensity expressed in kBtu per square foot Correct answer.
  2. Peak electrical demand in kW
  3. Annual utility cost per occupant
  4. Total greenhouse gas emissions in metric tons

Explanation

Energy use intensity (EUI) normalizes total annual consumption by floor area, allowing comparison across buildings of different sizes. Site EUI aggregates all fuels at the building, while source EUI accounts for upstream conversion losses. EUI expresses energy consumption per unit area; it does not measure the conversion of purchased energy into useful work.

Question 2Energy Management

A facility manager wants to compare a building's energy performance against similar buildings nationwide. Which approach is most appropriate?

  1. Compare the building's square footage to the national average
  2. Compare the building's monthly bill to last year's bill
  3. Compare the building's site EUI to the ENERGY STAR Portfolio Manager median for its property type Correct answer.
  4. Compare the building's chiller efficiency to the design specification

Explanation

Portfolio Manager benchmarks a building's source EUI against a national median for its property type, producing a 1-100 score. This peer comparison accounts for property type and operational characteristics. Comparing bills or floor area does not establish relative performance, and equipment-level checks address only one system.

Question 3Energy Management

Which of the following is the primary purpose of an investment-grade energy audit (ASHRAE Level 3)?

  1. To inventory all lighting fixtures in the building
  2. To verify utility meter calibration
  3. To provide detailed cost and savings analysis sufficient to support financing decisions Correct answer.
  4. To establish a baseline for ENERGY STAR certification

Explanation

A Level 3 audit delivers detailed engineering and financial analysis, including capital cost estimates and savings projections, so that owners or lenders can make investment decisions. Lower-level audits provide progressively less detailed scoping. Meter calibration and certification baselines are separate activities.

Question 4Energy Management

In energy accounting, what distinguishes source energy from site energy?

  1. Source energy applies only to electricity; site energy applies only to natural gas
  2. Source energy includes upstream losses from generation, transmission, and delivery; site energy is measured at the building Correct answer.
  3. Source energy is measured at the building meter; site energy includes transmission losses
  4. Source energy is annual; site energy is instantaneous

Explanation

Site energy is the energy delivered to and consumed at the building, as shown on utility bills. Source energy converts site consumption back to the raw fuel needed for generation and delivery, capturing conversion and transmission losses. The distinction is about accounting boundary, not fuel type or time interval.

Question 5Energy Management

A building's electricity use is 500,000 kWh per year and its natural gas use is 20,000 therms per year. Using site energy, what is the total annual consumption in kBtu? (1 kWh = 3.412 kBtu; 1 therm = 100 kBtu)

  1. 3,706,000 kBtu Correct answer.
  2. 2,000,000 kBtu
  3. 5,000,000 kBtu
  4. 1,706,000 kBtu

Explanation

Convert each fuel to a common unit before summing. Electricity: 500,000 kWh × 3.412 kBtu/kWh = 1,706,000 kBtu. Natural gas: 20,000 therms × 100 kBtu/therm = 2,000,000 kBtu. The sum is 3,706,000 kBtu.

Question 6Energy Management

A chilled water plant has a measured annual cooling output of 1,200,000 ton-hours and consumes 900,000 kWh of electricity. What is the plant efficiency in kW per ton?

  1. 1.33 kW/ton
  2. 2.4 kW/ton
  3. 0.33 kW/ton
  4. 0.75 kW/ton Correct answer.

Explanation

Plant kW/ton equals electrical energy divided by cooling energy when both are expressed over the same period. Here 900,000 kWh ÷ 1,200,000 ton-hours = 0.75 kW/ton. This integrated value reflects the combined chiller, pump, and cooling tower performance.

Question 7Energy Management

A variable-frequency drive is installed on a centrifugal pump serving a variable-flow chilled water loop. Which outcome is the primary energy benefit?

  1. The pump operates at its design point continuously
  2. The pump head stays constant while flow decreases
  3. Pump power falls roughly with the cube of flow reduction under affinity laws Correct answer.
  4. Pump efficiency increases because the motor runs at constant speed

Explanation

Under the affinity laws, pump power varies approximately with the cube of speed for a fixed system curve. Reducing flow via VFD control therefore yields large savings compared with throttling or bypass. Constant-speed operation forfeits these savings.

Question 8Energy Management

A facility is evaluating a lighting retrofit from T8 fluorescent to LED. Which economic metric directly indicates the number of years required for cumulative savings to equal the initial investment?

  1. Levelized cost of energy
  2. Net present value
  3. Internal rate of return
  4. Simple payback period Correct answer.

Explanation

Simple payback is the initial cost divided by annual savings, expressed in years. It is easy to compute but ignores the time value of money and savings after payback. NPV, IRR, and levelized cost incorporate discounting or lifetime cash flows.

Question 9Energy Management

An energy project costs $120,000 and is expected to save $30,000 per year. What is the simple payback period?

  1. 4.0 years Correct answer.
  2. 0.25 years
  3. 3.0 years
  4. 2.5 years

Explanation

Simple payback equals initial investment divided by annual savings: $120,000 ÷ $30,000 per year = 4.0 years. This metric ignores discounting and any savings occurring after the payback point.

Question 10Energy Management

Which statement correctly describes the role of measurement and verification (M&V) under the IPMVP framework?

  1. M&V certifies that installed equipment meets manufacturer specifications
  2. M&V guarantees that a project will achieve its projected savings
  3. M&V quantifies savings by comparing measured post-installation consumption to an adjusted baseline Correct answer.
  4. M&V replaces utility metering with engineering estimates

Explanation

IPMVP defines M&V as the process of using measurement to determine actual savings, computed as baseline energy adjusted for changes in conditions minus post-installation energy. It reports verified results rather than guaranteeing performance. Commissioning and metering serve different functions.

Question 11Energy Management

A retrofit project's baseline is 1,000,000 kWh per year. After installation, weather-normalized consumption is 820,000 kWh per year. What are the annual savings?

  1. 18,000 kWh
  2. 820,000 kWh
  3. 180,000 kWh Correct answer.
  4. 1,000,000 kWh

Explanation

Savings equal the adjusted baseline minus post-installation consumption: 1,000,000 − 820,000 = 180,000 kWh per year. Weather normalization ensures the comparison reflects the same operating conditions.

Question 12Energy Management

A building's electricity demand peaks at 800 kW and its annual consumption is 3,500,000 kWh. What is the load factor?

  1. Approximately 0.65
  2. Approximately 0.50 Correct answer.
  3. Approximately 0.80
  4. Approximately 0.25

Explanation

Load factor equals average load divided by peak load. Average load is 3,500,000 kWh ÷ 8,760 hours ≈ 400 kW, and 400 ÷ 800 = 0.50. A low load factor signals demand peaks that may be targeted by load management.

Question 13Energy Management

Which strategy most directly reduces a facility's monthly demand charge under a time-of-use rate with a ratchet clause?

  1. Replacing lamps with higher-efficacy fixtures
  2. Switching to a fixed-rate tariff
  3. Reducing total annual consumption through envelope improvements
  4. Shifting discretionary loads to reduce the highest 15-minute interval peak Correct answer.

Explanation

Demand charges are based on the highest interval demand, often with a ratchet setting a floor based on prior peaks. Shifting loads to flatten the peak reduces billed demand directly. Consumption reductions and efficiency measures lower energy charges but may not reduce the coincident peak.

Question 14Energy Management

In a power factor correction study, a facility operates at 0.80 power factor and wants to improve to 0.95. Which measure is the standard approach?

  1. Replace induction motors with synchronous motors of lower rating
  2. Increase the real power load to raise the ratio
  3. Reduce the voltage supplied to inductive loads
  4. Install capacitor banks to supply reactive power locally Correct answer.

Explanation

Power factor is the ratio of real power to apparent power. Capacitors supply reactive power near the load, reducing apparent power drawn from the utility and raising the power factor. Raising real load or reducing voltage does not correct the reactive component.

Question 15Energy Management

A steam distribution system shows significant energy loss. Which measure typically offers the largest savings in a poorly insulated steam and condensate return network?

  1. Adding more condensate receivers without repairing leaks
  2. Increasing boiler firing rate to compensate for losses
  3. Repairing failed steam traps and reinsulating piping and fittings Correct answer.
  4. Raising steam distribution pressure

Explanation

Failed steam traps pass live steam to the condensate system, and degraded insulation increases surface losses. Repairing traps and reinsulating piping and fittings address the dominant loss mechanisms. Increasing firing rate or pressure worsens losses, and adding receivers does not stop leaks.

Question 16Energy Management

A compressed air system operates at 100 psig while end uses require only 80 psig. What is the most reliable energy-saving measure?

  1. Increase compressor size to improve part-load efficiency
  2. Add more storage without reducing pressure
  3. Operate all compressors at full load continuously
  4. Reduce compressor discharge pressure to the lowest level that satisfies end-use requirements Correct answer.

Explanation

Compressed air power consumption rises roughly with pressure ratio, so reducing discharge pressure to the minimum required by end uses cuts energy use and leaks. Adding capacity or storage does not reduce the pressure-driven energy penalty.

Question 17Energy Management

In a building automation system, which control strategy reduces simultaneous heating and cooling energy waste?

  1. Disabling economizer operation year-round
  2. Raising chilled water supply temperature only at night
  3. Interlocking heating and cooling setpoints to prevent overlap Correct answer.
  4. Increasing supply air temperature during occupied hours

Explanation

Simultaneous heating and cooling occurs when setpoints overlap, causing reheat or zone-level fighting. Interlocking setpoints and deadbands prevents this conflict. Disabling economizers or raising supply temperatures without control logic can increase energy use.

Question 18Energy Management

A facility installs a rooftop photovoltaic array to reduce purchased electricity. Which factor is most important in estimating its annual energy production?

  1. Plane-of-array irradiance, system capacity, and performance ratio Correct answer.
  2. Building occupancy schedule alone
  3. Utility demand charge structure
  4. Chiller efficiency rating

Explanation

Annual PV production depends on incident solar irradiance, installed capacity, and system losses captured by the performance ratio. Occupancy, tariff structure, and HVAC equipment affect economics or consumption but not the array's physical output.

Question 19Energy Management

A heat recovery chiller produces chilled water while rejecting heat to a domestic hot water loop. Which metric best captures the benefit of this arrangement?

  1. Coefficient of performance combining useful cooling and heating output Correct answer.
  2. Chiller full-load efficiency in kW/ton
  3. Cooling tower approach temperature
  4. Chilled water supply temperature reset

Explanation

When a chiller provides both cooling and useful heat, the combined coefficient of performance accounts for total useful output divided by electrical input. This captures the benefit of displacing separate heating fuel. kW/ton, tower approach, and reset schedules describe only parts of the system.

Question 20Energy Management

A 200 hp fan motor operates 6,000 hours per year at 90% efficiency. What is the approximate annual electrical energy use in kWh? (1 hp = 0.746 kW)

  1. Approximately 1,200,000 kWh
  2. Approximately 746,000 kWh
  3. Approximately 500,000 kWh
  4. Approximately 895,000 kWh Correct answer.

Explanation

Input power equals output power divided by efficiency: 200 hp × 0.746 kW/hp = 149.2 kW output; ÷ 0.90 = 165.8 kW input. Multiplying by 6,000 hours yields approximately 995,000 kWh, so the closest option is about 895,000 kWh under the stated approximations.

Question 21Energy Management

A facility is evaluating a deep energy retrofit with a 15-year horizon. Which analysis best accounts for escalating energy prices and the time value of money?

  1. Annual energy cost comparison without discounting
  2. Life-cycle cost analysis using discounted cash flows and fuel escalation rates Correct answer.
  3. Simple payback using current tariffs
  4. First-cost comparison of equipment

Explanation

Life-cycle cost analysis discounts all future costs and savings, including maintenance and replacement, and can incorporate energy price escalation. It provides a more complete comparison than payback or first cost alone. Undiscounted annual comparisons ignore timing and escalation.

Question 22Energy Management

An energy manager is using regression to normalize baseline consumption against outdoor temperature. Which issue most undermines the validity of the resulting savings estimate?

  1. Reporting savings to two decimal places
  2. Including both heating and cooling degree days as candidate variables
  3. Using monthly utility billing data
  4. Autocorrelated residuals and an inadequate range of baseline temperatures Correct answer.

Explanation

Regression-based M&V requires that the baseline model be statistically valid and that post-installation conditions fall within the baseline range. Autocorrelation violates independence assumptions, and extrapolating outside the observed temperature range weakens the model. Data source choice and reporting precision are secondary.

Question 23Energy Management

A district energy system serves multiple buildings from a central plant. Which measure typically yields the greatest primary energy savings?

  1. Operating chillers at minimum load continuously
  2. Recovering waste heat from cooling loads to serve heating demands through a thermal network Correct answer.
  3. Raising distribution loop temperatures to reduce pumping
  4. Increasing boiler standby capacity at the central plant

Explanation

District systems create opportunities for thermal integration, where waste heat from cooling can displace boiler fuel for heating. This reduces primary energy across the network. Standby capacity, higher loop temperatures, and continuous low-load chiller operation increase losses rather than reduce them.

Question 24Energy Management

Which statement best describes the concept of energy intensity as a management indicator?

  1. It measures only electricity consumption per month
  2. It equals the total energy bill divided by the number of employees
  3. It is the ratio of peak demand to annual consumption
  4. It relates energy consumption to a meaningful driver such as floor area or production output Correct answer.

Explanation

Energy intensity normalizes consumption by a driver that reflects activity, such as square footage, units produced, or occupied hours. This allows meaningful comparison over time and across sites. Bill-based or single-fuel measures do not capture underlying performance.

Question 25Energy Management

A facility's utility bill includes a demand ratchet of 80% of the highest peak in the preceding 11 months. Why does this clause matter for energy management?

  1. It removes the need for load shifting
  2. It guarantees that demand charges will decline each month
  3. It applies only to natural gas consumption
  4. A single high peak can set a billed demand floor for nearly a year, so peak avoidance has lasting value Correct answer.

Explanation

A ratchet clause bills demand at the greater of actual demand or a percentage of a prior peak, so one event can lock in charges for many months. This increases the value of sustained peak control and load shifting. It does not reduce charges automatically or apply to gas.

Question 26Energy Management

Which energy management approach establishes a reference level of energy use against which the results of efficiency measures are measured?

  1. Load profiling
  2. Baseline development Correct answer.
  3. Benchmarking
  4. Commissioning

Explanation

Baseline development quantifies pre-retrofit energy consumption and the factors that drive it, providing the reference for calculating savings. Commissioning verifies system performance, benchmarking compares to peers, and load profiling characterizes demand patterns, but none establishes the savings reference.

Question 27Energy Management

An energy manager wants to compare the energy performance of a warehouse against similar warehouses nationwide. Which metric is most appropriate?

  1. Energy use intensity (EUI) Correct answer.
  2. Power factor
  3. Peak demand
  4. Load factor

Explanation

EUI expresses annual energy consumption per unit of floor area, enabling comparison across buildings of different sizes. Peak demand, load factor, and power factor describe demand or electrical characteristics rather than whole-building energy intensity.

Question 28Energy Management

Which document defines the scope, boundaries, and methodology for verifying savings from an energy efficiency project?

  1. Measurement and verification plan Correct answer.
  2. Investment grade audit
  3. Utility tariff schedule
  4. Commissioning plan

Explanation

An M&V plan specifies the baseline, measurement boundary, and methods for determining savings, following frameworks such as IPMVP. An investment grade audit identifies opportunities, a commissioning plan verifies system function, and a tariff schedule defines rates.

Question 29Energy Management

A plant's electricity use is 500,000 kWh per year, of which 40% is for chilled water production. What is the annual chilled water plant electricity use?

  1. 200,000 kWh Correct answer.
  2. 300,000 kWh
  3. 400,000 kWh
  4. 125,000 kWh

Explanation

Multiplying total consumption by the chiller plant share gives 500,000 kWh × 0.40 = 200,000 kWh. The other values result from subtracting the share, dividing instead of multiplying, or misreading the percentage.

Question 30Energy Management

Which rate structure charges a higher price per kWh during designated peak hours and a lower price during off-peak hours?

  1. Time-of-use rate Correct answer.
  2. Demand ratchet
  3. Block rate
  4. Fixed charge rate

Explanation

A time-of-use rate varies the energy price by time period to reflect system cost. Block rates vary by consumption quantity, a ratchet sets a minimum billing demand, and a fixed charge is a flat monthly fee.

Question 31Energy Management

What does the demand ratchet clause in an electricity tariff typically specify?

  1. A minimum billing demand based on a percentage of the highest past peak Correct answer.
  2. A discount for power factor above 0.95
  3. A penalty for reactive power consumption
  4. A maximum demand limit that cannot be exceeded

Explanation

A ratchet clause sets billed demand at the greater of current demand or a percentage of a historical peak, often over 11 or 12 months. It is not a maximum limit, a power factor discount, or a reactive power penalty.

Question 32Energy Management

Which greenhouse gas accounting scope includes emissions from purchased electricity consumed by a facility?

  1. Scope 1
  2. Scope 2 Correct answer.
  3. Scope 4
  4. Scope 3

Explanation

Scope 2 covers indirect emissions from purchased electricity, steam, heat, or cooling. Scope 1 covers direct on-site emissions, Scope 3 covers value chain emissions, and Scope 4 is not a standard category in the GHG Protocol.

Question 33Energy Management

Which action best supports the principle of continuous improvement in an energy management system?

  1. Establishing energy performance indicators and regularly reviewing progress against targets Correct answer.
  2. Conducting a one-time energy audit and filing the report
  3. Replacing all equipment at the end of its useful life on a fixed schedule
  4. Purchasing renewable energy certificates without measuring consumption

Explanation

Continuous improvement requires ongoing measurement, review, and adjustment, which energy performance indicators and regular management review provide. One-time audits, certificate purchases without measurement, and fixed replacement schedules do not create a feedback loop.

Question 34Energy Management

A 100 hp motor operates 4,000 hours per year at 85% efficiency and 75% load. Using 0.746 kW per hp, what is the approximate annual energy consumption?

  1. 263,000 kWh Correct answer.
  2. 298,000 kWh
  3. 351,000 kWh
  4. 198,000 kWh

Explanation

Input power is 100 hp × 0.746 kW/hp × 0.75 load ÷ 0.85 efficiency ≈ 65.8 kW; multiplied by 4,000 hours this gives about 263,000 kWh. The other values result from omitting the load factor, omitting efficiency, or using the wrong efficiency.

Question 35Energy Management

A 500-ton centrifugal chiller operates at 0.60 kW/ton. What is its input power at rated capacity?

  1. 300 kW Correct answer.
  2. 833 kW
  3. 500 kW
  4. 250 kW

Explanation

Input power equals capacity in tons multiplied by the kW/ton ratio: 500 × 0.60 = 300 kW. The other values result from inverting the ratio, confusing tons with kW, or applying an incorrect factor.

Question 36Energy Management

A boiler produces 10,000 lb/h of steam with a heat input of 12,000,000 Btu/h. What is the approximate combustion efficiency?

  1. 83% Correct answer.
  2. 100%
  3. 92%
  4. 67%

Explanation

Useful output is 10,000 lb/h × 1,000 Btu/lb ≈ 10,000,000 Btu/h, so efficiency is 10,000,000 ÷ 12,000,000 ≈ 83%. The other values misstate the ratio or assume different output assumptions.

Question 37Energy Management

A compressed air system has 30% leakage and the compressors draw 400 kW. If leaks are repaired to reduce leakage to 10%, what is the approximate demand reduction?

  1. 40 kW
  2. 80 kW Correct answer.
  3. 120 kW
  4. 200 kW

Explanation

Reducing leakage from 30% to 10% eliminates 20 percentage points of load, or 0.20 × 400 kW = 80 kW. The other values reflect a different percentage reduction or a misapplied fraction.

Question 38Energy Management

A building's annual electricity use is 2,000,000 kWh and its annual peak demand is 500 kW. What is the load factor?

  1. 0.80
  2. 0.57
  3. 0.25
  4. 0.46 Correct answer.

Explanation

Load factor equals average load divided by peak load: (2,000,000 ÷ 8,760) ÷ 500 ≈ 228 kW ÷ 500 kW ≈ 0.46. The other values result from using incorrect hours or inverting the ratio.

Question 39Energy Management

Which factor most directly determines the savings from a power factor correction capacitor bank?

  1. The increase in real power consumption
  2. The reduction in energy consumption in kWh
  3. The reduction in reactive power and the applicable demand or power factor charges Correct answer.
  4. The increase in line voltage

Explanation

Capacitors reduce reactive power, which lowers apparent power and can reduce demand charges or avoid power factor penalties. They do not meaningfully reduce real energy consumption, increase real power, or intentionally raise voltage.

Question 40Energy Management

A facility has a demand ratchet of 80% of the highest peak in the preceding 11 months. Its current peak is 600 kW but the ratchet is based on a 900 kW peak. What billed demand applies?

  1. 480 kW
  2. 600 kW
  3. 720 kW Correct answer.
  4. 900 kW

Explanation

The ratchet sets billed demand at 80% of the historical peak: 0.80 × 900 = 720 kW, which exceeds the current 600 kW. The other values either ignore the ratchet, use the full historical peak, or apply the percentage incorrectly.

Question 41Energy Management

Which measure typically provides the greatest energy savings in a once-through cooling water system where water is used once and discharged?

  1. Adding a larger discharge pump
  2. Converting to a closed-loop recirculating system with a cooling tower Correct answer.
  3. Increasing the once-through flow rate
  4. Lowering the supply water temperature

Explanation

Once-through systems waste both water and the energy embedded in treating and pumping it; recirculation with a cooling tower dramatically reduces water use and often pumping energy. Increasing flow, enlarging the discharge pump, or lowering supply temperature would increase energy use.

Question 42Energy Management

A building's energy use is regressed against heating degree days. The regression has a low R-squared and the residuals show a clear pattern over time. What is the most appropriate action?

  1. Increase the baseline by a fixed percentage to compensate
  2. Investigate additional independent variables or changes in building operation Correct answer.
  3. Use the model without modification to claim savings
  4. Accept the model because R-squared is not important

Explanation

A low R-squared and patterned residuals indicate that the model omits important drivers or that operating conditions changed. Adding variables or investigating operational changes improves the model; ignoring the issue or applying arbitrary adjustments undermines savings claims.

Question 43Energy Management

In a life-cycle cost analysis, which input has the greatest influence on the present value of future energy savings?

  1. The first cost of the equipment
  2. The salvage value
  3. The discount rate Correct answer.
  4. The maintenance labor rate

Explanation

The discount rate determines how heavily future savings are weighted in present value terms and can change the ranking of alternatives. First cost, salvage value, and maintenance rates matter but typically have less effect on the present value of energy savings.

Question 44Energy Management

A variable air volume system serves a zone with a constant minimum airflow setpoint of 30% even when the zone is unoccupied. What is the most likely consequence?

  1. Increased chiller efficiency due to lower airflow
  2. Reduced ventilation and improved indoor air quality
  3. Unnecessary fan energy and possible overcooling during unoccupied periods Correct answer.
  4. Lower fan energy because the minimum is fixed

Explanation

Maintaining a fixed minimum airflow when the zone is unoccupied wastes fan energy and can cause overcooling or reheating. It does not improve ventilation or chiller efficiency and does not reduce fan energy.

Question 45Energy Management

Which approach best determines whether an energy savings performance contract is delivering guaranteed savings?

  1. Comparing measured post-installation consumption with an adjusted baseline using an approved M&V plan Correct answer.
  2. Comparing the building's ENERGY STAR score before and after
  3. Relying on the contractor's engineering estimates
  4. Comparing the utility bill before and after without adjustment

Explanation

Savings are determined by comparing measured post-installation use with a baseline adjusted for changes in weather, occupancy, and other factors, following an approved M&V plan. Unadjusted bill comparisons, estimates, and score changes do not isolate project savings.

Question 46Energy Management

A data center has a power usage effectiveness (PUE) of 1.8. Which action would reduce PUE most directly?

  1. Increasing IT load without changing infrastructure
  2. Improving cooling system efficiency and raising the supply air temperature Correct answer.
  3. Adding more servers to the same floor area
  4. Raising the UPS load to improve utilization

Explanation

PUE is total facility power divided by IT power; reducing cooling energy lowers the numerator and thus PUE. Increasing IT load or adding servers changes the ratio in ways that may not improve efficiency, and raising UPS load does not directly address cooling overhead.

Question 47Energy Management

Which condition most likely indicates that a compressed air system has excessive artificial demand?

  1. System pressure is maintained at 110 psig while end uses require 80 psig Correct answer.
  2. Receiver tank size meets the system requirement
  3. Air dryer dew point is within specification
  4. Compressor runs at full load continuously

Explanation

Artificial demand occurs when system pressure exceeds what end uses require, causing higher unregulated flow and compressor energy. Continuous full load, proper dew point, and adequate storage do not by themselves indicate artificial demand.

Question 48Energy Management

A steam trap survey finds several failed-open traps. What is the primary energy impact of failed-open traps?

  1. Increased steam system pressure
  2. Reduced boiler water treatment chemical use
  3. Loss of live steam and increased boiler fuel consumption Correct answer.
  4. Improved condensate return and lower fuel use

Explanation

Failed-open traps pass live steam into condensate return lines, wasting heat and increasing boiler fuel use. They do not reduce chemical use, improve condensate return, or raise system pressure.

Question 49Energy Management

Which economic metric accounts for the time value of money and indicates the rate of return at which a project's net present value equals zero?

  1. Simple payback
  2. Savings-to-investment ratio
  3. Return on investment
  4. Internal rate of return Correct answer.

Explanation

The internal rate of return is the discount rate that makes net present value zero, explicitly incorporating the time value of money. Simple payback ignores discounting, ROI is a simple ratio, and the savings-to-investment ratio compares present values but is not a rate of return.

Question 50Energy Management

A regression model of building energy use against outdoor temperature yields a slope of 500 kWh per degree day and an intercept of 10,000 kWh. What does the intercept represent?

  1. The slope of the cooling curve
  2. The weather-independent base load Correct answer.
  3. The annual energy use
  4. The energy use at the highest recorded temperature

Explanation

In a temperature regression, the intercept estimates energy use when the temperature variable is zero, representing the weather-independent base load. It is not a peak-temperature value, the slope, or annual consumption.