AEE Certified Energy Manager (CEM) study guide
AEE Certified Energy Manager (CEM) · Work through your exam, one topic at a time.
The Certified Energy Manager (CEM®) is a professional credential awarded by the Association of Energy Engineers to individuals who can demonstrate broad, practical knowledge of energy management. It is aimed at engineers, facility and plant managers, energy consultants, commissioning and sustainability staff, and others accountable for reducing energy use and cost in commercial, institutional, and industrial facilities. The AEE Certified Energy Manager (CEM) study guide has 10 sections and about 3,034 words.
01Codes and Standards
Codes questions test scope, not memorized numbers. ASHRAE Standard 90.1 governs energy efficiency in commercial buildings and residential buildings more than three stories above grade.
303 words, about 2 min02Electrical Power Systems and Motors
Real power (kW) does work, apparent power (kVA) loads conductors and transformers, and reactive power (kVAR) is the gap between them: kW = kVA x PF. Three-phase real power = 1.732 x V(line-line) x I x PF.
319 words, about 2 min03Maintenance and Commissioning
Reactive (run-to-failure) maintenance is cheap to administer and expensive in downtime; preventive maintenance is calendar-based; predictive (condition-based) maintenance uses vibration analysis, oil analysis, infrared thermography, and ultrasonic leak detection to intervene just before failure. Reliability-centered maintenance prioritizes tasks by failure consequence using FMEA and MTBF data.
265 words, about 1 min04Energy Audits and Instrumentation
ASHRAE Standard 211 defines the levels the exam expects. Level 1 is a walk-through: utility bill analysis, rough benchmarking, a list of low-cost opportunities, and no rigorous savings calculations.
302 words, about 2 min05CHP Systems and Renewable Energy
Combined heat and power recovers waste heat from on-site generation. Prime movers include reciprocating engines (strong electrical efficiency plus recoverable jacket and exhaust heat), gas turbines and microturbines (high-temperature exhaust usable for steam or absorption cooling), fuel cells (high electrical efficiency, low emissions), and back-pressure steam turbines.
315 words, about 2 min06HVAC Systems
COP = EER / 3.412, and 1 kW/ton equals COP 3.517 and EER 12.0. EER is a full-load rating, SEER is seasonal for small unitary equipment, and IEER or IPLV captures part-load behavior, which is the honest number for a chiller running most hours at 30 to 60% load.
304 words, about 2 min07Building Automation and Control Systems
Field DDC controllers run local sequences; supervisory controllers handle scheduling, trending, and alarms. Protocols include BACnet, Modbus, and LonWorks, with gateways translating between them.
295 words, about 1 min08Thermal Energy Storage Systems
Thermal energy storage decouples production from demand. Chilled water storage uses sensible heat: 1 ton-hour = 12,000 Btu, and with a 10 F usable delta-T one cubic foot of water holds about 624 Btu, so plan roughly 19 cubic feet per ton-hour plus unusable stratified volume.
325 words, about 2 min09Lighting Systems
Lumens measure light output, efficacy is lumens per watt, illuminance is foot-candles (1 fc = 10.76 lux), and lighting power density is W/ft2. Codes regulate LPD, not illuminance, and LPD must be computed from fixture input watts, meaning lamp watts plus ballast or driver losses, not lamp watts alone.
298 words, about 1 min10Energy Savings Performance Contracting and Measurement and Verification
Measurement and verification rests on a transparent, adjusted baseline. IPMVP defines four options: A (retrofit isolation with key parameters measured, others stipulated), B (retrofit isolation with all parameters measured), C (whole-building metering), and D (calibrated simulation).
308 words, about 2 min