Get Instant Access to CEM Practice Exam Questions [Q22-Q43]

NO.22 A compressed-air distribution system has one section that frequently has low pressure when demand for compressed air is high. How can you resolve the problem without increasing energy consumption?

NO.23 A controlled valve is full closed when it gets a signal of 4 mA. The valve is full open when it gets a signal of
20 mA. With a control signal of 8 mA, what is the valve position?

NO.24 Problems Caused by Harmonic Distortion
Which of the following problems is unlikely to be caused by harmonic distortion?
SELECT THE CORRECT ANSWER

NO.25 A 100-kW electrical load has a power factor of 75%. What capacitance, in KVAR, will improve the power factor to 95%?

NO.26 What type of heat exchanger is commonly built into AHU’s or large RTU’s, can be used to recover heat from exhaust air, and may cause cross-contamination between heat exchange fluids?
Select the Correct Answer

NO.27 Which of the following is NOT a typical benefit of performance contracting from the building owner’s perspective?

NO.28 When should commissioning be included in the design and construction of a facility?

NO.29 An air-conditioning unit delivers 10,000 kJ/h (thermal cooling). The equipment uses single-phase electrical power at 220-volt and 5.25 amps with a power factor of 100%. Calculate the coefficient of performance (COP).

NO.30 In a PID control system, what is the purpose of the Proportional Gain?

NO.31 An air-conditioning system at full load is rated at 70-kW (thermal cooling) and has a coefficient of performance (COP) of 4.1. What is the electrical load at full load?

NO.32 A 3 MW rated wind-powered turbine has a rotor diameter of 113 meters. What is the efficiency of the wind turbine at rated power if it is operating in wind power calculated at 8.6 MW? Assume an air density of 1.225 kg/m³.

NO.33 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.

NO.34 Which of the following is NOT a renewable-energy resource?
SELECT THE CORRECT ANSWER

NO.35 Which motor parameter is the most difficult to measure with precision?

NO.36 Which electric rate tariff would best cost justify a thermal energy storage (TES) system?

NO.37 Which of the following best describes a dead band in controls?

NO.38 Which of the following best describes a thermally-light building?

NO.39 A facility owner is considering installing a new chiller. The installed project cost will be $300,000. The annual savings from the energy-saving project will be $45,000 for the 20-year life of the chiller. If an energy- service company requires a minimum 20% return on investment (pre-tax), will the energy-service company agree to finance this project?

NO.40 An energy-saving project costs $540,000. The project will have maintenance costs of $25,000 per year. The energy savings from the project are $160,000 per year. The project has a life of 10 years with no salvage value. The minimum attractive rate of return (MARR) is 10%. Using end-of-year cash flows, calculate the net- present value (NPV) of the project.

NO.41 In general, which of the following is the least expensive and easiest way to finance an energy project?

NO.42 A facility has the thermal cooling load profile shown in the table below. The utility rate traffic has an no-peak time-of-use period that begins at 10:00 a.m ends at 7:00 p.m. What chiller capacity (output) is required for a load-leveling operating strategy?

[Question from the previous image, which was about chiller capacity for load leveling, but the table was missing]

NO.43 Which of the following is NOT included in commissioning documentation?