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Hospital Energy Audit |
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US Air Force Academy
Base Hospital Energy AuditC
 Purpose:
To identify and recommend energy conservation opportunities (ECOs) with a positive economic payback.
Description of Facility:
Full Service Hospital, 150,000 SF
- Surgical
- Outpatient Clinics
- Labor & Delivery
- Laboratory
- Emergency Clinic
- Pharmacy
- ICU/Patient Wards
- Food Service
- Nuclear Medicine
Facility Energy Usage:
 Energy Usage
(MBtu)
Combined ECO Savings
Energy Cost: $215,000
Energy Reduction 50-60%
Simple Payback 2.6 years
 Baseline EUI: 295 kBtu/SF/year
DoD Average: 209 kbtu/SF/year
Energy Conservation Opportunties:
The energy audit identified and recommended 16 ECOs with positive economic payback. The following is a summary of those ECOs:
- Automated Controls
Preheat Coil
Scheduled Start/Stop
Hot/Cold Deck Reset
Room Temperature Setback
- Central Plant
Water Side Economizer
Variable Frequency Drives
Premium Efficiency Motors
Chilled Water Temperature Reset
- HVAC Systems
Reduce Outside Air
Recirculate Air
Reduce Air Supply
Constant Volume AHUs to VAV
- Lighting Systems
T-8 Lamps, Electronic Ballasts
Compact Fluorescent Lamps
Occupancy Sensors
Daylighting Sensors
The following tables present a profile of the ECO evaluations:
| Automated Controls |
| ECO |
Problem |
Energy Wasted |
| Preheat Coil
Control |
Simultaneous
heating and cooling of air through AHUs.
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Energy was being
used to first preheat outside air to 70°F, then cooled down to 50°F.
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Scheduled
Start/Stop
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AHUs operate 24 hours/day. Most areas unoccupied at night. Only ER,
ICU, ORs required air flow during unoccupied periods.
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Fan,
coil energy was being used unnecessarily to provide comfortable space conditions during
unoccupied periods.
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| Hot Deck/Cold Deck
Reset |
Multizone temperatures reset according to fixed outside air temperature.
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Air was being
excessively heated and cooled. Multizone AHUs were not being controlled to meet needs of
the worst-case zone.
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| Central Plants |
| ECO |
Problem |
Energy Wasted |
| Waterside
Economizer |
Existing flat-plate heat exchanger was not being utilized. Chiller was operating
throughout year.
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Chiller was
providing chilled water at 0.6 kW/ton. Cooling tower was capable of meeting winter loads
at 0.2 kW/ton.
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| Variable Frequency
Drives |
Chilled water pumps were operating at constant speed. Three-way control valves
were used.
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Chilled water was
bypassing coils at part-load. Pump motors were operating at full electrical load during
part thermal load periods.
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| Premium Efficiency
Motors |
Standard efficiency motors were being utilized on some fans and pumps.
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Standard
efficiency motors are typically 3-8% less efficient than premium efficiency motors.
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| HVAC Systems |
| ECO |
Problem |
Energy Wasted |
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Reduce
Outside Air:
AHU SF-4
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AHU SF-4, 100% outside air unit, was being operated at constant volume rate 24
hours per day.
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Medical Standards
allow OR AHUs to operate at reduce air volumes during unoccupied periods.
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Reduce
Outside Air:
AHU SF-6
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AHU SF-6, 100% outside air unit, was being operated at constant volume rate 24
hours per day. Approximately 70% of areas served are unoccupied at night and on weekends.
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Air was being
delivered to zones on four floors at all times. Only one floor required conditioned air 24
hours/day. Other three floors were unoccupied at nights and on weekends.
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Recirculate
Air to
AHU SF-6
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AHU SF-6, 100% outside air unit, was being operated at constant volume rate 24
hours per day. Exhaust fan EF-3 exhausts air from space into mechanical room.
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AHU SF-6 serves
offices, ICU, and patient wards. These areas do not require 100% outside air. Less energy
is needed to properly condition return air than is required for outside air.
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