CVEN 5020 BUILDING ENERGY AUDITS FALL 2007
University of Colorado at Boulder 1
Homework No. 6
Due October 25, 2007
Problem No. 1:
(a) Using a power quality meter and the valuable help of Larson Lab Manager (Mr. Veronica),
measure the electrical characteristics of the following equipment located in the Larson Laboratory:
1. Fan motor for the air handling unit.
2. Pump motor for the chilled water system.
3. Electrical heater in one of the full zones.
Measure the basic characteristics of each piece of equipment including power (kW), voltage,
current, power factor, and total harmonic distortion (THD).
(b) Based on the results, assess the operating conditions of the equipment. In particular, determine
if capacitors are needed to improve the power factor of the motors and estimate the total harmonic
current of each piece of equipment.
Problem No. 2:
After a physical survey of the HVAC Larson Laboratory, provide a brief description of the HVAC
systems that heat and cool the various zones. In particular, describe HVAC controls and heating
and cooling sources.
Problem No. 3:
Consider a 100,000 sqft two story building in Denver. A 80,000 cfm air handling unit services the
building. The building is occupied 50 hrs per week. The fuel cost is 7.00 per 106 Btu's (MMBtu)
and electricity cost is $0.08 per kWh.
Determine the energy and cost savings for the following ECOs
(a) Reset Hot Deck Temperature: 2oF in summer and 3oF in winter. Assume 50% of airflow is in
hot deck.
(b) Reset Cold Deck Temperature: 2.0 Btu/lb of enthalpy. Assume 50% of airflow is in cold deck.
(c) Reduced Minimum Outdoor Air: from 25% to the minimum required. Assume two options for
estimating the minimum ventilation requirements
(i) Ventilation rate of 20 cfm/person and 400 people in the building, and
(ii) Indoor CO2 level should not exceed 700 ppm relative to outdoor CO2 level. Each
person of 400 people generates 0.0106 cfm of CO2.
Assume that the average indoor temperature is 70oF.
(d) Low Leakage Dampers: reduce damper leakage from 10% to 1%.
