Problem: There is an imbalance between exhaust air and makeup air in the commercial kitchen, which leads to a negative pressure in the building. The hot and humid outdoor air is drawn into the building, resulting in condensate on supply registers and interior walls. The cigarette odor from the next-door casino is also drawn into the building.
Approach: The energy assessment team measured the airflow at exhaust fans and supply fans using pitot tubes and vane anemometers. The measurement shows the makeup air is only at 52% of the design value. A 2000 ft3/min dedicated outdoor air system (DOAS) is propoosed to meet the ventilation requirement while pressuring the building.
Result: The proposed DOAS shows energy savings of 7.3% to 9.3% compared with the existing system.
Air Conditioning System in a Manufacturing Facility
Problem: The existing air conditioning equipment can not keep up with the building thermal load in a manufacturing facility.
Approach: The energy assessment team measured the airflow rate through evaporators to check whether it is in the normal range of 350 to 450 ft3/min per 12,000 Btu/h.
Result: Airflow rates from five 10-ton units were checked, four of which had an airflow in a range of 3,800 to 5,000 ft3/min. One unit only had 2,300 ft3/min. It is recommended to check the fan motor and driving belt to correct the airflow rate.
Exhaust Air System in an Airplane Paint Hangar
Problem: Six 50-horsepower exhaust fans and four 75-horsepower supply fans are used in an airplane paint hangar. These oversized fans draw significant power when started simultaneously.
Approach: The energy assessment team examined the energy saving potential of installing variable frequency drive (VFD) on these fans for soft start and adjusting fan speeds.
Result: The proposed VFD installation shows annual savings of 687,649 kWh in electricity and $55,012 in utility expense.
Building Insulation in a Convenient Store
Problem: A convenient store located in an old single-story building has minimum insulation.
Approach: The energy assessment team examined the energy saving potential of adding building insulation and LED lighting retrofit.
Result: LED lighting retrofit will yield savings of 10,824 kWh in electricity and $1,318 in utility expense. Adding R13 insulation to exterior wall and R30 insulation to roof will save up to 5,541 kWh electricity and $444 utility expense. The combination of LED retrofit and addition insulation will lead to savings of 30,440 kWh in electricity and $2,890 in utility expense.
Lighting Retrofit in a Manufacturing Facility
Problem: A 165,000 ft2 manufacturing facility requests an energy saving evaluation of replacing fluorescent lights with LED lights.
Approach: The energy assessment team calculated the energy and monetary savings based on the proposed lighting retrofit plan.
Result: The proposed lighting retrofit can yield monthly savings of $354 in demand charge and $501 in energy charge, leading to an annual saving of $10,270
