Retro-Commissioning Final Report 8/17/2012€¦ · Retro-commissioning (RCx) is a systematic, documented process that identifies operational and maintenance improvements in existing

Retro-Commissioning Final Report

8/17/2012

Located at:

Presented to:

Sponsored by:

Project # 0391001

Submitted By:

Final Retro-commissioning Report Disclaimer

Disclaimer

Part of the intent of the Retro-commissioning Report is to identify recommended retro-commissioning

measures related to energy savings, O&M, comfort and indoor air quality for the customer’s

consideration. While the energy savings associated with the findings in this report have been reviewed

for technical accuracy and are believed to be reasonably accurate, the actual results may vary. As a result,

and/or Hammel, Green and Abrahamson, Inc. (HGA) are not liable if estimated energy

savings or economics are not realized. All energy savings and opinions of cost in the report are

“ballpark” and for informational purposes, and are not to be construed as a design document or as

guarantees.

The shall independently evaluate any advice or suggestions provided in this report. In

no event will and/or HGA be liable for the failure of the customer to achieve a specified

amount of energy or demand savings, the operation of the customer’s facilities, or any incidental or

consequential damages of any kind in connection with this report or the installation of evaluated

measures.

Final Retro-commissioning Report Contents

Contents

Section Page

EXECUTIVE SUMMARY ......................................................................................................................................... I

SECTION 1 PROJECT CONTACTS ............................................................................................................. 1-1

SECTION 2 INTRODUCTION ....................................................................................................................... 2-1

SECTION 3 PROJECT OPPORTUNITIES SUMMARY ............................................................................ 3-1

SECTION 4 FACILITY DESCRIPTION ....................................................................................................... 4-1

4.1 GENERAL FACILITY INFORMATION ............................................................................................................... 4-1 4.2 ENERGY SYSTEMS ........................................................................................................................................ 4-3 4.3 ENERGY USE AND COSTS ............................................................................................................................. 4-9 4.4 BUILDING DOCUMENTATION ...................................................................................................................... 4-13 4.5 BUILDING EQUIPMENT ................................................................................................................................ 4-14

SECTION 5 INVESTIGATION RESULTS ................................................................................................... 5-1

5.1 INVESTIGATION ACTIVITIES .......................................................................................................................... 5-1 5.2 AIR HANDLING UNITS .................................................................................................................................. 5-1 5.3 CHILLED WATER SYSTEM ............................................................................................................................ 5-6 5.4 VAV SYSTEM .............................................................................................................................................. 5-8 5.5 SNOW MELT ................................................................................................................................................. 5-9 5.6 DOMESTIC HOT WATER ............................................................................................................................... 5-10 5.7 LIGHTING ................................................................................................................................................... 5-10 5.8 MASTER LIST ............................................................................................................................................. 5-11

SECTION 6 APPENDICES ............................................................................................................................. 6-1

APPENDIX A: DETAILED FIM CALCULATIONS ....................................................................................................... 6-1

Final Retro-commissioning Report Executive Summary

i

Executive Summary

The is located at 2

. The 187,000 square foot building has four stories, and it was completed in 1994.

The building includes 27 classrooms varying in size from a 16-seat conference room to a 387-seat

auditorium. Each classroom is equipped with technology including projectors and audio systems. The

building also houses one of the largest information technology centers on campus.

The goal of this retro-commissioning study is to identify energy and operational savings, meet current

building requirements, while improving or maintaining occupant comfort and indoor air quality. The

study focuses on the existing HVAC equipment and the Building Automation System (BAS) but also

touches on envelope and lighting system. It identifies issues and opportunities to make the entire

facility run more efficiently.

The facility was evaluated in heating and in cooling mode. It was found that

has significant potential for reducing energy consumption and a resulting overall short return

on investment. The measures that result in the largest energy savings include modifications to the

control sequences for the fan powered reheat boxes and building scheduling modifications.

A summary of the savings and implementation cost for the calculated measures is shown in Table 1.

Please note that the energy savings associated with each measure can in most cases not be added as

most measures will impact the energy savings associated with another measure.

http://en.wikipedia.org/wiki/Conference_room

http://en.wikipedia.org/wiki/Auditorium

http://en.wikipedia.org/wiki/Video_projector

http://en.wikipedia.org/wiki/Information_technology

Final Retro-commissioning Report Facility Description

- 2012ii

Table 1: Summary of Calculated Measures

FIM

No.

Recommended

Improvement

Opinion of

Implemen-

tation Cost

Annual

Energy

Cost

Savings

(End User

Cost)

Simple

Payback

(years)

(End User

Cost)

Annual

Energy Cost

Savings

(Mid-American

Cost)**

Simple

Payback

(years)

(Mid-American

Cost)

1

Modify AHU

schedules in

summer to 6a-6p,

7 days/week.

$100 $37,141 0.1 $8,031 0.1

2

Implement AHU

duct static

pressure reset

$4,000 $5,409 0.7 $2,884 1.4

3

AHU-1 Demand

Control

Ventilation &

Occupancy Sensor

Control

$12,000 $2,348 5.1 $1,141 10.5

4

Add variable

frequency drive to

CW P-6 / CW

Leaky Valves

$4,465 $15,743 0.3 $2,428 1.8

5

Modify fan

powered VAV

box sequence

$19,500 $97,800 0.2 $32,383 0.6

6 Modify snow melt

control $1,000 $20,758 0.1 $10,359 0.1

7

Domestic Hot

Water Recirc

Pump Control

$1,000 $321 3.1 $161 6.2

8 Artwork Lighting $1,100 $314 3.5 $168 6.6

Total* $43,165 $179,834 0.24 $57,555 0.75

* The individual energy savings cannot be added as many of the measures will impact the energy savings

associated with the other measures. The energy savings in this table are added together as a total to

illustrate the order of magnitude of the energy savings and simple payback.

** Mid-American Cost Savings is calculated using $0.0427/kW-hr and $6/MMBtu for steam with 80%

efficiency conversion.

Final Retro-commissioning Report Project Contacts

- 20121-1

Section 1 Project Contacts

Table 2: Roles, responsibilities and contact information for RCx participants

Name Role Organization Contact Information

mailto:[email protected]





2012 1-2

Name Role Organization Contact Information





Final Retro-commissioning Report Introduction

2012 2-1

Section 2 Introduction

Retro-commissioning (RCx) is a systematic, documented process that identifies operational and

maintenance improvements in existing buildings and brings the buildings up to the design intentions of

its current usage.

RCx typically focuses on energy-using equipment such as mechanical equipment, lighting and related

controls, and usually optimizes existing system performance, rather than relying on major equipment

replacement, typically resulting in improved indoor air quality and comfort, reduced amount of O&M,

as well as added control, energy, and resource efficiency.

RCx includes a study of past utility bills, interviews with facility personnel, a review of the controls

system, and auditing the entire building, in heating and in cooling modes. Then, diagnostic monitoring

and functional tests of building systems are executed and analyzed. Building systems are retested and

re-monitored to fine-tune improvements. This process helps find and repair operational problems.

Final Retro-commissioning Report Project Opportunities Summary

2012 3-1

Section 3 Project Opportunities Summary

Numerous action items related to the operation and maintenance of the

were discovered during the RCx investigation phase. Some of these measures are directly related to

optimizing energy efficiency, while others are meant to ensure the building systems meet the

requirements for climate control and occupant comfort.

There is substantial opportunity for utility costs to be reduced with a modest initial investment. For the

purposes of this report, savings are calculated based on two utility rate structures as detailed in Table 3:

Utility Pricing. Table 4, below, summarizes the energy efficiency measures.

Table 3: Utility Pricing

Pricing End User Pricing

Electric $0.0427/kW-hr $0.0801/kW-hr

Chilled Water 0.9 kW-hr/ton $24.35/MMBtu

Steam $6/MMBtu $15.04/MMBtu

Final Retro-commissioning Report Project Opportunities Summary

2012 3-1

Table 4: Master List of Calculated Energy Saving Measures

FIM

No.

Recommended

Improvement

Electric

Savings

(kWh)

Chilled

Water

Savings

(MMBtu)

Steam

Savings

(MMBtu)

Opinion of

Implemen-

tation Cost

Annual

Energy

Cost

Savings

(End User

Cost)

Simple

Payback

(years)

(End User

Cost)

Chilled

Water

Savings

(kWh)

Annual

Energy Cost

Savings

(Mid-American

Cost)**

Simple

Payback

(years)

(Mid-American

Cost)

1

Modify AHU

schedules in

summer to 6a-6p,

7 days/week.

60,392 1,192 218 $100 $37,141 0.1 89,400 $8,031 0.1

2

Implement AHU

duct static

pressure reset

67,534 - - $4,000 $5,409 0.7 - $2,884 1.4

3

AHU-1 Demand

Control

Ventilation &

Occupancy Sensor

Control

7,800 5.7 106 $12,000 $2,348 5.1 428 $1,141 10.5

4

Add variable

frequency drive to

CW P-6 / CW

Leaky Valves

11,101 610 - $4,465 $15,743 0.3 45,750 $2,428 1.8

5

Modify fan

powered VAV

box sequence

204,093 1,894 2,347 $19,500 $97,800 0.2 142,050 $32,383 0.6

6 Modify snow melt

control 2,849 - 1365 $1,000 $20,758 0.1 - $10,359 0.1


2012 3-2

FIM

No.

Recommended

Improvement

Electric

Savings

(kWh)

Chilled

Water

Savings

(MMBtu)

Steam

Savings

(MMBtu)

Opinion of

Implemen-

tation Cost

Annual

Energy

Cost

Savings

(End User

Cost)

Simple

Payback

(years)

(End User

Cost)

Chilled

Water

Savings

(kWh)

Annual

Energy Cost

Savings

(Mid-American

Cost)**

Simple

Payback

(years)

(Mid-American

Cost)

7

Domestic Hot

Water Recirc

Pump Control

406 - 19 $1,000 $321 3.1 - $161 6.2

8 Artwork Lighting 3,924 - - $1,100 $314 3.5 - $168 6.6

Total* 358,099 3,702 4,055 $43,165 $179,834 0.24 277,628 $57,555 0.75

* The individual energy savings cannot be added as many of the measures will impact the energy savings associated with the other measures. The

energy savings in this table are added together as a total to illustrate the order of magnitude of the energy savings and simple payback.

** Mid-American Cost Savings is calculated using $0.0427/kW-hr and $6/MMBtu for steam with 80% efficiency conversion.

Detailed lists of all RCx findings can be found in Section 5.8. They are divided into two categories; the first category contains issues that have

low implementation costs and are generally related to operational and equipment sequence modifications. The second category deals with

additional measures that were not calculated.


2012 4-1

Section 4 Facility Description

4.1 GENERAL FACILITY INFORMATION

The P houses the at the in

. Completed in 1994, it is an 187,000-square-foot (17,400 m2) postmodern facility that

houses the .

The building embodies the style of the Pentacrest structures with its use of aggregate stone and is a

modern twist on the turn-of-the century buildings found at the heart of campus. Its style is also

reminiscent of financial institutions such as the New York Stock Exchange and its use of a "money-

green" paint scheme reinforces its financial focus.

includes 27 classrooms varying in size from a 16-seat conference room to a

387-seat auditorium. Each classroom is equipped with technology including projectors and audio

systems. The building houses one of the largest information technology centers on campus, as well as

offices, the , which serves breakfast, lunch and

dinner. The open atrium spaces, study corners and outdoor patio provide places for students to study or

relax. The building also includes a below grade parking garage. An illustration of the facility’s plan is

provided in Figure 1.

The facility is closed on holidays, and normally operates under the schedule detailed in Table 5.

Table 5: Hours (except library)

Monday - Thursday 6:30 am - 11 pm

Friday 6:30 am - 9 pm

Saturday 7:30 am - 6 pm

Sunday 7:30 am - 11 pm

Table 6: Hours

Monday - Thursday 8 am - Midnight

Friday 8 am - 7 pm

Saturday Noon - 5 pm

Sunday Noon - Midnight

http://en.wikipedia.org/wiki/Tippie_College_of_Business

http://en.wikipedia.org/wiki/University_of_Iowa

http://en.wikipedia.org/wiki/Iowa_City,_Iowa

http://en.wikipedia.org/wiki/Postmodern_architecture

http://en.wikipedia.org/wiki/Pentacrest

http://en.wikipedia.org/wiki/Construction_aggregate

http://en.wikipedia.org/wiki/New_York_Stock_Exchange

http://en.wikipedia.org/wiki/Conference_room

http://en.wikipedia.org/wiki/Auditorium

http://en.wikipedia.org/wiki/Video_projector

http://en.wikipedia.org/wiki/Information_technology

http://en.wikipedia.org/wiki/Atrium_(architecture)

http://en.wikipedia.org/wiki/Patio


2012 4-2

Figure 1:


2012 4-3

4.2 ENERGY SYSTEMS

4.2.1 Building Automation Systems

The central HVAC equipment in the building is controlled by a Johnson Controls Extended

Architecture Building Automation System (BAS). This includes the following:

• Air handling units: AHU-1 through AHU-5

• Fan coil units

• Chilled water distribution

• Hot water converters

• Hot water pumps

• VAV boxes with full DDC devices

• Snow melt systems

• Generator room

• Smoke damper

4.2.2 Facility Heating, Cooling, and Ventilation

Air Handling Units

has five (5) air-handling units (AHUs). AHU-1 is a single-zone constant

volume unit that serves the . AHU-2 through AHU-5 are variable air volume

units that provide ventilation and conditioning to the rest of the building. Table 7 provides details for

each of the AHUs. The discharge air temperature for AHU-2 through AHU-5 is currently maintained

at 55°F. The static pressure setpoints are not reset on any of these units. Spaces served by AHU-2

through AHU-5 have variable air volume fan-powered boxes. Boxes in perimeter areas have hot water

reheat coils, while some of those in interior zones lack reheat. Spaces that need year round cooling

such as computer labs and server rooms are also served by fan coil units.


2012 4-4

Table 7: Air Handling Units List

HVAC System

AHU Service Area SF HP SF

VFD RF HP RF VFD CFM

Minimum

OA Schedule

Design

CW

Flow

(gpm)

Design

CW

∆T (F)

Heating

Coil

AHU-1 Buchanan Auditorium

(NW Ground Floor) 15 5 11,000 7a-10p 71 15 Steam

AHU-2 NW 1st,2nd and 3rdFloors 75 √ 30 √ 50,000 10,000 5a-10p 286 14.6 None

AHU-3 North Center 1st,2nd,3rd

and 4th Floors 75 √ 30 √ 50,000 10,000

5a-11p (M-F)

7a-10p

(Wknd)

286 14.3 None

AHU-4 South Center 1st,2nd,3rd

and 4th Floors 75 √ 30 √ 50,000 10,000

5a-11p (M-F)

7a-10p

(Wknd)

286 14.3 None

AHU-5 South 1st,2nd and 3rd

Floors 75 √ 30 √ 50,000 10,000

5a-10p (M-F)

7a-10p

(Wknd)

286 14.3 None


2012 4-5

Heating System

Heating hot water is provided by two (2) steam to hot water heat exchangers. Steam is provided by the

campus steam plant. Heating hot water is circulated by a pair of lead-lag 15-horsepower pumps (P-1

and P-1a) with VFDs. The heating hot water supply temp is reset from 135°F to 180°F as shown in

Table 5.

Table 8: Hot Water Temperature Reset Schedule

When Outdoor Air Temp is: Hot Water Supply Temp is:

20°F 180°F

65°F 135°F

Chilled Water system

Chilled water is supplied to the building by the campus chilled water plant. Pumps P-2 and P-2a are

the main chilled water pumps for the building. These 40-horsepower pumps with operate in lead-lag

during the cooling season. P-2 has a VFD and P-2a is a constant volume pump. During the heating

season, the chilled water coils on the AHUs are drained and the pump P-6, a 3-horsepower constant

volume pump, is used to supply the fan coil units with chilled water.

Parking Garage Ventilation

Ventilation for the parking garage is provided by an exhaust fan that is controlled by a carbon

monoxide sensor. No heating is provided to the garage space. The entrance/exit ramp is equipped with

a glycol snowmelt system.

The heating, cooling, and ventilation systems have electrically actuated direct digital controls, and are

scheduled and operated by a networked building automation system.

Snowmelt System

Five main entrance areas and the entrance/exit ramp for the parking garage are equipped with a glycol

snow and ice melt system. The glycol loop is heated by a 20 gpm hot water to glycol heat exchanger.

The loop supply temperature is linearly reset from 140°F to 105°F based on outdoor air temperature as

shown in Table 9. A control valve on the heating hot water side of the heat exchanger is modulated to

control the loop supply temperature.


2012 4-6

Table 9: Snowmelt System Temperature Reset Schedule

When Outdoor Air Temp is: Snowmelt Loop Supply

Temp is:

45°F 140°F

0°F 105°F

The glycol is circulated by a pair of lead-lag 10-horsepower pumps with VFDs. According to the

controls drawings, the VFD modulates to maintain a constant differential pressure in the loop.

However, the controls drawings indicate that there are no control valves in the glycol side of the loop.

Trend data confirms that the pumps do not modulate.

Domestic Hot Water Heating

Domestic hot water is provided by a small A.O Smith 40 gallon water heater. The unit has an integral

steam coil. The unit also has recirculation pump that runs 24/7.

Variable Air Volume Boxes

The VAV terminal units at are electronic with full DDC devices and

control. There are 237 fan-powered VAV reheat terminals to provide zone thermal adjustments.

Boxes in perimeter areas have hot water reheat coils, while some of those in interior zones lack reheat.

The University installed new occupancy sensors in most of the spaces during the winter of 2011-2012.

The proposed design calls for these sensors to turn off lighting and allow the space temperature to

float ±3ºF when the space is vacant (vs. ±1ºF when occupied). Part of the funding for the project came

from Federal money and the project was completed in April of 2012.

Supplemental and Perimeter Heating

A limited number of hot water unit heaters are located in entrance areas to provide supplemental heat.

There are no unit or fin tube heaters located in the office or classroom areas.

There are also approximately 10 unit heaters located above the drop ceiling in the parking garage.

These heaters are used to provide floor heating in the winter months to avoid cold floors in the interior

spaces above the garage.


- 20124-7

4.2.3 Chilled Water System

Cooling for the building is provided by chilled water from the campus chilled water plant.

has a dedicated chilled water interface and chilled water meter. The supply

temperature from the chilled water loop is typically between 42 and 43°F.

The building ∆T (difference between loop return temperature and building supply temperature) is a

function of outdoor air temperature. The ∆T ranges between 2°F in the winter months and 25°F in the

summer months.

Figure 2: Chilled Water Performance, 2010-11

Chilled water is used for all the air handlers as well as a limited number of fan coil units used for

server room cooling.


- 20124-8

4.2.4 Steam System

Steam from the campus steam plant is used for air handler steam heating coils and in the steam

convertors to heat water for the hydronic hot water system. The hot water temperature is

automatically reset based on outside air temperature.

has dedicated steam meter which was replaced in April of 2007.

4.2.5 Electrical

Power is fed to local distribution panels from two 1,500 kVA, oil-filled transformers. Two high

voltage switches and two 480 volt isolation switches isolate the transformers. Standard conductors

feed modern 3,000 amp, double-ended switchgear through an interior feed selector. The switchgear

powers three 1,200 amp vertical bus ducts. TPower is distributed to various electrical closets at

480/277 volts.

4.2.6 Lighting

The interior lighting at is quite varied in design and effect. The lighting

scheme has a unified design theme and dramatic appearance.

According to facilities personnel, the building stocks twenty-four (24) different types of lamps. Many

areas of the building were originally designed with occupancy sensors. It appears that many of these

sensors no longer work. The University is currently pursuing a project to install new occupancy

sensors in each space. The proposed design calls for these sensors to turn off lighting and allow the

space temperature to float when the space is vacant. Part of the funding for the project is from Federal

money and the project was completed in the Spring of 2012.

3.2.5 Other Loads

Room C220J is a server room with 16 servers. There are also computers in offices, classrooms, the

computer lab and email checking stations.


- 20124-9

4.3 ENERGY USE AND COSTS

marginal cost of electricity from is $0.0427 per kWh.

Steam for the building is supplied by the campus’s coal and biomass plant, and chilled water is

supplied by the campus chilled water plan. For the purposes of this report, savings are calculated

based on end user utility rates of $0.0801 per kWh for electricity, $24.35 per MMBtu of chilled water,

and $15.04 per MMBtu of steam.

4.3.1 Electricity Use and Costs

Figure 3 illustrates the monthly electricity consumption at over the past

five fiscal years. Electricity consumption varies between 150 and 329 MWh per month and shows no

significant seasonal variation. The relative consistency of electricity consumption seasonal is due to

the building being supplied with district chilled water. The average monthly (and annual) electricity

consumption has remained fairly constant since fiscal year 2006/2007. It appears that the billing

cycles were standardized in fiscal year 10-11, as the monthly variations have been greatly reduced.

Due to the reduced activity in the building in the summer, there is likely a potential to reduce electric

energy consumption during the summer months by shutting off lighting, equipment and fans.

Figure 3: Electricity Use Profile –


- 20124-10

4.3.2 Steam Use and Costs

Figure 4 illustrates the monthly steam consumption at over the past five

fiscal years. Steam consumption reflects a strong seasonal variation peaking in December and January

and at a minimum in the summer months. The average maximum monthly steam consumption in the

past 2 years is approximately 1,800 MMBtu/month, while the summer monthly minimum has

fluctuated between 140 and 500 MMBtu. Steam consumption at

increased dramatically in the winter months beginning in the winter of 2009. This increase coincides

with the start-up of a snow melt system used at the building entrances and steps at the West side

auditorium entrance. It should also be noted that a new steam meter was installed on March 7th, 2007.

Summer steam consumption is used primarily for VAV box reheat coils via the steam convertors and a

small amount for domestic hot water.

Figure 4: Steam Consumption Profile –

4.3.3 Chilled Water Use and Costs

Figure 5 illustrates the monthly chilled water consumption at over the

past five fiscal years. Chilled water consumption reflects a strong seasonal variation, peaking in the

summer months as the building cooling and dehumidification demands increase, and dipping in the

winter months, when cooling needs are limited to server rooms. The chilled water consumption rate is

steady during the heating season (November through March), approximately 300 MMBtu per month.

A significant portion of the winter chilled water usage can be eliminated by fixing leaking cooling

valves as illustrated by the reduced chilled water consumption in FY12 December, January and

February after we manually valved off the valves that were observed to leak (March was an unusually


- 20124-11

warm month in 2012).

Figure 5: Chilled Water Consumption Profile –

4.3.4 Total Energy Use and Costs

Figure 6 illustrates the total yearly energy expenses for for the fiscal

year 2011.


- 20124-12

Figure 6: Energy Cost (electricity, chilled water and steam) –

Based on the 2011 fiscal year, is paying $3.11/ft2, which is higher than

would be anticipated for this type of building.

4.3.5 Energy Benchmarking

HGA could not enter into Portfolio Manager because higher educational

facilities and libraries are not among the building types currently supported by the program. However,

Portfolio Manager may add this and other building types in the future. HGA is available to advise and

assist with Portfolio Manager benchmarking if the tool expands its offerings to include higher

educational facilities and library buildings.

As a point of comparison, according to the 2003 Commercial Buildings Energy Consumption Survey

(CBECS) conducted by the U.S. Department of Energy’s Energy Information Administration, the

national average energy intensities by fuel type for K-12 educational buildings were 31.5 kBtu/square

foot for electricity and 48 kBtu/square foot for natural gas, for a total average intensity of 83.1

kBtu/square foot. ’s energy intensity is 154 kBtu/square foot, 1.8 times

the national average for K-12 educational facilities. However, the CBECs average for educational

buildings does not take into account the presence of IT server rooms, which elevate the energy load in

the facility. The also has an extended schedule when compared to K-12

educational facilities. During the school year, the building is in operation until 11p with the computer

lab open until 1:30a, which is approximately double the occupancy time of a typical K-12 school.


- 20124-13

4.4 BUILDING DOCUMENTATION

The Facilities Department posted documentation pertaining to

on-line on SharePoint. The documentation includes the following:

• Mechanical Drawings

• Electrical Drawings

• AHUs Locations and Zones Served

• Hawks Energy Team Reports

• No systems manual is available for at this time.


- 20124-14

4.5 BUILDING EQUIPMENT

Table 10: Air Handling Units List

HVAC System

AHU Service Area Location SF

HP

SF

VFD

RF

HP

RF

VFD CFM

Min

OA

(cfm)

Schedule

Design

CW

Flow

(gpm)

Design

CW

∆T (F)

Heating

Coil

AHU-1

Buchanan

Auditorium

(NW Ground

Floor)

W14 15 5 11,000 7a-10p 71 15 Steam

AHU-2 NW 1st,2nd and

3rdFloors W406A 75 √ 30 √ 50,000 2,000 5a-10p 286 14.6 None

AHU-3

North Center

1st,2nd,3rd and

4th Floors

W406A 75 √ 30 √ 50,000 2,200

5a-11p (M-F)

7a-10p

(Wknd)

286 14.3 None

AHU-4

South Center

1st,2nd,3rd and

4th Floors

S406C 75 √ 30 √ 50,000 2,200

5a-11p (M-F)

7a-10p

(Wknd)

286 14.3 None

AHU-5 South 1st,2nd

and 3rd Floors S406C 75 √ 30 √ 50,000 2,200

5a-10p (M-F)

7a-10p

(Wknd)

286 14.3 None


- 20124-15

Table 11: Exhaust Fans

Exhaust Fans

Exhaust Service Area CFM HP Location SP (w.c.)

EF-1 See Plans 2,725 2 In Line 1.5

EF-2 See Plans 3,125 3 In Line 1.5

EF-3 Ground “B” 700 1/6 Wall 24” SQ .25

EF-4 A,B,C,D See Plans 18,000 2 Wall .25

EF-5 Ground “C” 1,150 1/2 In Line SQ .5

EF-6 See Plans 2,000 1/2 Wall .5


- 20124-16

4.5.1 Heat Exchanger Schedule

has three shell and tube heat exchangers that produce hot water from the

steam from the campus steam plant.

Heat exchangers HX-1 and HX-1A are located in ground floor mechanical room. They serve the

building’s main hot water loop (associated pumps are P-1 and P-1A). HX-2 is a water to water heat

exchanger that serves the slab snow melting system. The shell flow rate of HX-2 is 17.5 gpm at 1.9 psi

pressure drop based on 40% propylene glycol, entering water temperature 80F and leaving water

temperature 110F.

Table 12: PBB Heat Exchanger Schedule

PBB Heat Exchanger

Humid-

ifier

Service

Area

Tube Side Shell

Model Number

GPM EWT LWT PD lb/hr Pressure

HX-1 HWS 500 150 180 2’ 7353 10 psig B&G SU165-2

HX-1A HWS 500 150 180 2’ 7353 10 psig B&G SU165-2

HX-2 GWS 20 120 150 1’ CHX-636-2S

4.5.2 Direct Steam Humidification

The steam humidifier schedule for AHU-1, 2, 3, 4 and 5 at is as follows:

Table 13: PBB Steam Humidifier Schedule

PBB Steam Humidifiers

Humid-

ifier

Service

Area

Outdoor

CFM kW

#/hr Cap.

Required

Manu-

facturer Model Number

H-1 AHU-1 30 85.2 Dri-Steam VPC-101010 Single

Tube

H-2 AHU-2 2,000 42 121 Dri-Steam VPC-141414




Due to recurring maintenance issues and the high cost of operating the electric humidifiers, they are no

longer in use. HGA recommends that the humidifiers remain out of service, as there are no requirements,


- 20124-17

such as local codes or ASHRAE standards that require such a facility to be humidified to maintain

occupant comfort or functional needs.


- 20124-18

4.5.3 Pumps and Valves

Table 14: Pumps

Pumps

Pump Service Type GPM HP RPM

Feet

of

Head

P-1 Hot Water Supply B&G 1510 4E 500 15 1750 75

P-1A Hot Water Supply B&G 1510 4E 500 15 1750 75

P-2Chilled Water

Supply B&G 1510 8x10x101/2 1200 40 1750 80

P-2AChilled Water

Supply B&G 1510 8x10x101/2 1200 40 1750 80

P-3 Condensate Pump Roth 90S Duplex - 35

gallon rec. 40 2 1750 69

P-4 Domestic Hot water B&G PD385 15 1/2 1750 30

P-5 Sump Aurora 511 20 1/3 1800 20

P-6Chilled Water

Supply B&G 1510 1Y4BC 70 3 1800 80

P-7 Fire Aurora 6-481-18B 1500 125 1770 231

P-8 Fire Aurora JP-231-5 5 1.5 231

P-9 Sump Aurora 522 Duplex 80 1 25

P-10 Sump Flyght M3102-212

Grinder 60 5 60

P-11 Snow Melt B&G 1535 353T 17.5 3 65

P-12 Snow Melt Viking FH456M 3 1 1800 50

Final Retro-commissioning Report Investigation Results

- 2012

5-1

Section 5 Investigation Results

5.1 INVESTIGATION ACTIVITIES

This section presents the recommendations for repairs and modifications to optimize the building

performance based on HGA’s observations.

5.2 AIR HANDLING UNITS

5.2.1 AHU-2, 3, 4, 5 – Schedule Modifications

AHU-2 through 5 are the main air handlers for the building and serve all areas except the ground floor

auditorium space. Currently, these AHU’s run on the following schedules:

AHU Tag Weekdays Weekends

AHU-2 5a-10p 5a-10p

AHU-3 5a-11p 7a-10p

AHU-4 5a-11p 7a-10p

AHU-5 5a-10p 7a-10p

These schedules fairly closely match the building schedule, except in the summer months when the

building is open from 6:30a-6p and 7:30a-6p on the weekends. Therefore, it is recommended that

AHU-2 through 5 operation schedules are modified in the summer months from approximately June 1

through August 31. The new summer schedule would be from approximately 6a-6p. The energy

savings for this measure includes air handler fan savings, air handler chilled water savings, fan

powered box fan savings and fan powered box reheat savings. Based on the proposed schedule, the

total savings and opinion of cost for this measure would be as follows:

Annual

Electricity

Savings (kWh)

Annual Chilled

Water (MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

60,392 1192 218 $100

Additional savings opportunities exist for AHU schedule modifications. Because the building has fan

powered boxes with reheat coils throughout the building except in core spaces, in the winter months it


- 2012

5-2

is feasible to keep the AHU’s off until the building has significant occupancy at approximately 7a.

The fan powered boxes could provide the heat for the warm-up period from 5a-7a. At 7a the AHU’s

would turn on to provide the ventilation air for the building.

It should also be noted that in the summer of 2012 there are M.B.A night classes occurring in the

building outside of the published building hours. It is recommended that the various University

departments better coordinate building use in the summer months so that not all the buildings are

being used at extreme part load. Better coordinating building usage would allow more buildings to be

shut down during the summer, resulting in significant energy savings.


- 20125-3

5.2.2 AHU-2, 3, 4, 5 – Reset Duct Static Pressure Setpoint

AHU-2 through 5 are variable air volume air handlers with variable speed drives on both the supply

and return fans. The supply fan speed is controlled to maintain a constant duct static pressure when

the unit is on. For AHU-3, 4 and 5 this pressure is maintained at 1.2”. AHU-2 is maintained at 2.2”.

Because the majority of the boxes served by the AHU’s have fan powered box, the discharge air static

pressure setpoint typically can be set lower than a traditional VAV system.

To further evaluate the feasibility of a discharge air static pressure reset, the box damper positions

were evaluated on 5/3/2012 when there was a relative high cooling load on the building. The graph

below illustrates the damper positions of all the building boxes.

Figure 7: VAV Box Damper Positions

The majority of the damper positions are between 15%-35% open. There were some boxes that were

100% open but some of these boxes were not communicating with the BAS system, resulting in false

readings. If all the boxes are working properly, it is likely that the discharge static pressure setpoint

can be significantly reduced using reset schedule based on damper position. It is expected that the

range of reset would be from 0.5”-1.0”. However, most of the run hours would be at the lower end of

this range. The current setpoint for the majority of the air handlers is 1.25”. The new average duct

static setpoint would be expected to be .7”. Based on the proposed measure, the total savings and

opinion of cost for this measure would be as follows:


- 20125-4

Annual

Electricity

Savings (kWh)

Annual Chilled

Water (MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

67,534 - - $4,000


- 2012

5-5

5.2.3 AHU-1 – Implement Demand Control Ventilation and Occupancy Control

AHU-1 serves the basement auditorium and is used as a large lecture hall. The unit typically runs

from 7a-10p during the school year. This unit is a constant volume unit with fixed speed supply and

return fans. When the unit is operating, the outside air dampers are set at a fixed position unless the

unit is economizing. The minimum outside air damper position is based on auditorium peak

occupancy. However, the space is rarely at full occupancy and is therefore, over-ventilated much of

the time when the unit is running.

To implement demand control ventilation, a CO2 sensor would be located in the space. The outside air

damper minimum position would be reset based on the space CO2 levels in a manner consistent with

those outlined in ASHRAE standard 62. Typically, CO2 levels are maintained at levels no higher than

1,100ppm.

In addition to the demand control ventilation, it is recommended to turn off AHU-1 when the

auditorium is vacant, but the unit is scheduled to be on. This would be accomplished by installing

occupancy sensors in the auditorium. When the room is vacant for over 15 minutes, the air handler

would turn off. If the room was occupied for over 5 minutes, the AHU would turn back on. Some fine

tuning of the sensor delays and control scheme would be required to avoid excessive cycling of the air

handler and avoid occupant complaints.

For the purposes of the calculation, the following assumptions were made:

- The minimum outside air quantity is 35% of the unit total supply cfm

- The demand control ventilation would result in an average outside air quantity of 15% of design

- The occupancy sensor would results in the AHU running only 80% of the scheduled time

- The unit would be economizing when the outside air is between 70°F and 30°F, and therefore no

savings from the demand control ventilation would be achieved

- AHU-1 is scheduled to run during the school year from 7a-10p

- Return air is 70°F and discharge air is 55°F in cooling and 65°F in heating

Annual

Electricity

Savings (kWh)

Annual Chilled

Water (MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

7,680 5.7 106 $12,000


- 2012

5-6

5.3 CHILLED WATER SYSTEM

There are two identical 40 HP chilled water pumps that serve the chilled water loop at

, P-2 and P-2A. They work on a lead/lag configuration. P-2 is on variable frequency

drive and maintains a constant differential pressure of 12 psi during the cooling season, per sequence

of operation. P-2A is the constant volume back up pump. Additionally, there is a smaller 3-HP

chilled water pump, P-6, that serves PBB during the winter months, when the building cooling load is

reduced to the fan coils serving the IT rooms.

Table 15: Chilled Water Pumps Characteristics

Pump Service Type GPM HP RPM

Feet

of

Head

P-2 Chilled Water

Supply B&G 1510 8x10x101/2 1200 40 1750 80

P-2A Chilled Water

Supply B&G 1510 8x10x101/2 1200 40 1750 80

P-6 Chilled Water

Supply (Winter) B&G 1510 1Y4BC 70 3 1800 80

5.3.1 Chilled Water Pump P-6 VFD Installation

Chilled water pump P-6 is used in the winter and at times of low cooling requirements to provide chilled

water to primarily to the fan coil units serving the server rooms. This pump is a constant volume pump.

During the first visit in November of 2011, it was found that the system differential pressure was 2-3

times the setpoint maintained by the main chilled water pump VFD’s in the summer operation mode.

With such a high differential pressure the chilled water valves on AHU-3 and AHU-4 did not close

completely and allowed (or increased the amount of) chilled water leaking through the valve when it was

commanded close. In order to reduce the system differential pressure, the throttling valve after P-6 was

closed almost all the way to match the differential setpoint in the summer mode of operation. After

throttling the pump, the leakage on 2 valves was eliminated. The graph below illustrates the chilled

water savings by eliminating the valve leakage.


- 20125-7

Figure 8: Chilled Water Savings from Pump Throttling

HGA recommends that a VFD is installed on this pump to reduce the pump speed to maintain the

differential pressure setpoint that is used on P-2 in the normal summer mode. All required differential

pressure sensors are already installed which reduces the project cost.

The energy and cost savings associated with adding the VFD to P-6 and eliminating the chilled water

valve leakage is estimated to be:

Annual

Electricity

Savings (kWh)

Annual Chilled

Water Savings

(MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

11,101 610 - $4,465


- 2012

5-8

5.4 VAV SYSTEM

HGA reviewed each variable air volume box at on the BAS system. The

following is a summary of potential issues discovered.

5.4.1 Modify Fan Powered Box Sequence of Operation

Prior to retrocommissioning the VAV boxes, U of I completed an energy efficiency project which

installed occupancy sensors throughout the spaces. The occupancy sensors control the room lights and

are also tied into the majority of the zone fan-powered VAV box. The newly implemented fan-powered

box sequence functioned the same way as without the occupancy sensor with the following

modifications:

• The boxes are now scheduled independently of the AHU serving it. Box schedules may be

reduced from the AHU schedule.

• When the rooms served by the box are unoccupied, the box will continue to run but the

temperature deadband is increased from ±1°F to ±3°F.

While the sequence implemented at PBB for the occupancy sensor controlled fan-powered boxes saves

some energy, there are additional sequence modifications that can be implemented to significantly

increase the energy savings from the occupancy sensor installation. Specifically, the follow changes are

recommended:

• The fan is allowed to go off when the room is vacant and the temperature setpoints are

maintained.

• The supply damper is closed when the room is vacant and the zone temperature is below cooling

setpoint temperature (i.e. either neutral or heating).

Energy savings calculations were performed for this measure using trend data from the BAS. The

savings from implementing this measure include AHU fan savings, AHU chilled water savings, fan

powered box fan savings and fan powered box reheat savings. There would also be improvements in

occupant comfort in the core areas that do not have reheat coils, as the spaces would be overcooled when

the rooms are vacant, as is currently occurring. The total savings and opinion of cost for this measure is

estimated to be:

Annual

Electricity

Savings (kWh)

Annual Chilled

Water Savings

(MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

204,093 1,894 2,347 $19,500

The implementation cost assumes that the existing VAV controllers can be used to implement the

proposed control strategy. The costs would be significantly higher if new VAV controllers were

required. U of I controls staff are currently investigating the feasibility of implementing this new control

strategy.


- 2012

5-9

5.4.2 Temperature Setpoints

HGA observed that some spaces had a very narrow deadband of just 1 degree (±0.5°F) Fahrenheit

between heating and cooling temperature setpoints, rather than the 4 degree deadband recommended by

AHSRAE. There seems to be no specific reason for this reduced value, as there are no know critical

spaces at . Spaces with a one degree deadband included rooms W7, W13,

C202 SW, C207East, C207 West, C220 SW, C220A Middle N, and C220D Middle S.

HGA recommends increasing deadband to 5°F. This range could be seasonally adjusted, for example

using 70°F and 75°F setpoints in winter and 68°F and73°F in the summer.

Finally, there is a wide variation in space temperatures and setpoints, ranging from 67°F through 75°F,

even in non-critical spaces.

HGA recommends evaluating the reason for this wide range of temperature setpoints as well as sensor

accuracy in order to maintain a more uniform temperature throughout the building. This would reduce

the amount of spaces where one terminal unit is heating while another is cooling.

5.5 SNOW MELT

5.5.1 Modify Snow Melt Control

An extensive snow melt system was installed throughout the building exterior in the summer of 2009. In

the past, the snow melt was scheduled to run when the outside air temperature was less than 40°F.

However, of all the hours the snow melt system is active, less than 20% of this time does the heating

provide any function. While snow melt sensors can be installed, it is recommended that the system be

controlled manual using a timer programmed into the BAS. A possible procedure could be that when

there is a forecast for snow accumulation in the next 36 hours, an assigned department from the facilities

staff, landscape services or energy management office would start the snow melt system. The system

would for example run for 48 hours and then turn off. Some timer adjustment may be necessary based on

the time it takes to heat the concrete slab.

The energy savings associated with this measure was calculated based on the average building steam use

prior to the snow melt installation compared to before the installation, normalized for weather. The snow

melt system is estimated to cost over $26,000/yr to operate when the system runs if the outside air is

below 40°F. If the system is operated manually, it is estimated that the annual operation cost is

approximately $6,000/yr. The table below summarizes the energy savings and opinion of cost for this

measure:

Annual

Electricity

Savings (kWh)

Annual Chilled

Water Savings

(MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

2,849 - 1,365 $1,000


- 2012

5-10

5.6 DOMESTIC HOT WATER

5.6.1 Schedule DHW Recirculation Pump

The current domestic water recirculation pump runs 24/7. It is recommended that the pump is scheduled

either through a stand-alone time clock or tied into the building automation system. The implementation

of this measure will not only save pump energy, but will also save the steam that is used to reheat the

recirculating hot water.

The table below summarizes the energy savings and opinion of cost for this measure:

Annual

Electricity

Savings (kWh)

Annual Chilled

Water Savings

(MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

406 - 19.2 $1,000

5.7 LIGHTING

5.7.1 Artwork Spotlight Lamp Replacement

There are 14 50W halogen bulbs used throughout the building to accent artwork. It is recommended that

the bulbs are replaced with LED lamps with equivalent light output. The LED bulbs, while more

expensive, will have approximately 10x longer life and use approximately 15% of the energy compared

to the halogen lamps.

The table below summarizes the energy savings and opinion of cost for this measure:

Annual

Electricity

Savings (kWh)

Annual Chilled

Water Savings

(MMBtu)

Annual Steam

Savings

(MMBtu)

Implementation

Costs ($)

3,924 - - $1,100


Pappajohn Business Bldg. RCx - 2012 5-11

5.8 MASTER LIST

5.8.1 Low Cost Measures

Table 16: Master List – Low Cost Measures

FIM

No.

Recommended

Improvement

Electric

Savings

(kWh)

Chilled

Water

Savings

(MMBtu)

Steam

Savings

(MMBtu)

Opinion of

Implemen-

tation Cost

Annual

Energy

Cost

Savings

(End User

Cost)

Simple

Payback

(years)

(End User

Cost)

Chilled

Water

Savings

(kWh)

Annual

Energy Cost

Savings

(Mid-American

Cost)**

Simple

Payback

(years)

(Mid-American

Cost)

1

Modify AHU

schedules in

summer to 6a-6p,

7 days/week.

60,392 1,192 218 $100 $37,141 0.1 89,400 $8,031 0.1

2

Implement AHU

duct static

pressure reset

67,534 - - $4,000 $5,409 0.7 - $2,884 1.4

3

AHU-1 Demand

Control

Ventilation &

Occupancy Sensor

Control

7,800 5.7 106 $12,000 $2,348 5.1 428 $1,141 10.5


- 2012

5-12

FIM

No.

Recommended

Improvement

Electric

Savings

(kWh)

Chilled

Water

Savings

(MMBtu)

Steam

Savings

(MMBtu)

Opinion of

Implemen-

tation Cost

Annual

Energy

Cost

Savings

(End User

Cost)

Simple

Payback

(years)

(End User

Cost)

Chilled

Water

Savings

(kWh)

Annual

Energy Cost

Savings

(Mid-American

Cost)**

Simple

Payback

(years)

(Mid-American

Cost)

4

Add variable

frequency drive to

CW P-6 / CW

Leaky Valves

11,101 610 - $4,465 $15,743 0.3 45,750 $2,428 1.8

5

Modify fan

powered VAV

box sequence

204,093 1,894 2,347 $19,500 $97,800 0.2 142,050 $32,383 0.6

6 Modify snow melt

control 2,849 - 1365 $1,000 $20,758 0.1 - $10,359 0.1

7

Domestic Hot

Water Recirc

Pump Control

406 - 19 $1,000 $321 3.1 - $161 6.2

8 Artwork Lighting 3,924 - - $1,100 $314 3.5 - $168 6.6

Total* 358,099 3,702 4,055 $43,165 $179,834 0.24 277,628 $57,555 0.75


- 2012

5-- 13 -

5.8.2 Capital Investment Measures

There were no capital investment measures that were recommended for the . Significant energy savings can be

achieved through low cost measures documented in the low cost measure master list above.

5.8.3 Other Measures

Other measures include improvements that were considered for the low cost improvements master list, but not included for one of the following

reasons:

- Insufficient information was available to calculate the potential savings and the savings were not considered significant.

- Calculations were performed but the savings was small and the paybacks periods were over 10 years. For these measure, the

recommendation in the table below is listed as “Review at later date”.

Table 17: Other Measures

FIM

No.

Equipment or

System ID Description of Finding Recommended Improvement Recommendation

9 VAV Boxes Boxes serving common areas have

different temperature set points

Software interlock temperature set points for

common areas to avoid simultaneous heating and

cooling

Implement

10 VAV Boxes

Boxes without occupancy sensors

serving typically unoccupied spaces

are not controlled efficiently.

Spaces would include mechanical

rooms, janitor closets, etc…

Modify programming so that these boxes are

allowed to go to a minimum cfm of 0 and have the

fan go off when the temperature set points are

satisfied. Also, the temperature set points can be

relaxed for these spaces, such as 68°F for heating

and 76°F for cooling during the scheduled

occupancy times.

Implement


- 2012

5-- 14 -

FIM

No.

Equipment or


11 VAV Boxes

Minimum flow on VAV boxes is

40%, which is likely higher than that

required by ASHRAE std 62.1.

Recalculate required minimum flow rates based

on room occupancy. This will reduce the amount

of cooling cfm required and also reduce the

amount of reheat occurring to maintain the

temperature set points. AHU outside air

requirements can also be recalculated at this time.

Implement

12 Steam Traps

Steam trap survey was recently

performed on the Pappajohn steam

traps.

Continue to perform steam trap survey at a

regular interval, such as every 3-5 years. Completed

13 Utility Room

Lighting

T12 fluorescent lamps are used in

the mechanical rooms.

Replace T12 lamps and ballasts with T8

equivalents.

Review at later

date

14 Atrium

Lighting

Atrium areas are lit with eight 250W

metal halide fixtures.

Replace metal halide fixture with LED

replacement.

Review at later

date

15 Parking

Lighting

Parking garage is lit with 124, 100W

high pressure sodium lamps.

Replace high pressure sodium lamps with LED

equivalent. Note: This lighting is the

responsibility of Transportation and Housing

Department, and not UE&M. However, it is still

mentioned here as a potential improvement that

would be undertaken by Transportation and

Housing.

Review at later

date

16 Classroom

Lighting

Classrooms use dimmable

incandescent lights

Replace with dimmable LED lamps with

equivalent output

Review at later

date


- 20125-- 15 -

FIM

No.

Equipment or


17 Steam Piping Steam pipe valves in ground floor

mechanical room are not insulated

Insulate steam pipe valves and all other piping

accessories with removable blankets Implement

18 AHU-2

On AHU-2, the abandoned

humidifier penetrations at the air

handler discharge in the mechanical

room are leaking discharge air.

Seal all unused penetrations on AHU-2 and the

other air handlers. Implement

19 AHU’s AHU’s start early to bring spaces to

temperature

Implement optimum start on AHU’s for cooling

only.

Review at later

date

20 Garage Unit

Heaters

Unit heaters located above the drop

ceiling in the garage are not on DDC

control

Install DDC controls on the 10 unit heaters in

order to more effectively control the space

temperature and avoid heating the space during

unoccupied times.

Review at later

date

Final Retro-commissioning Report Appendices

- 20126-1

Section 6 Appendices

APPENDIX A: DETAILED FIM CALCULATIONS

Note: A CD has been included with the excel spreadsheet calculations and all the associated weather

data. The information presented in this appendix is a summary of the calculation.


- 2012

6-2

FIM #1: AHU Scheduling

Current

AHU ScheduleAHU Schedule-

Fall/Spring Semester

AHU Schedule -

Summer

AHU-2 5a-10p/ 7 days No change5a-6p M-F

7a-5p Wknd

AHU-35a-11p/ M-F

7a-10p (Wknd)No change

5a-6p M-F

7a-5p Wknd

AHU-45a-11p/ M-F


5a-6p M-F

7a-5p Wknd

AHU-55a-10p/ M-F


5a-6p M-F

7a-5p Wknd

Proposed

Note: To simplify the calculation, it w as assummed that all AHU

schedules are shutoff at 6p, rather than 10p in the summer.


- 2012

6-3

Savings AHU-2 AHU-3 AHU-4 AHU-5 FP VAV's Total/Avg Comments

CFM of Supply Air 28,174 28,174 28,174 28,174

112,695

Per Trend Data from

5/6-5/9 w hen ON

and per Query of

BAS 4/19-4/25

CFM of Outside Air 9,297 9,297 9,297 9,29737,189

OA based on design

values

CFM of Return Air 18,876 18,876 18,876 18,876

AHU SF Motor Size (hp) 75 75 75 75300 Nameplate hp

AHU SF Motor Eff iciency 94.1% 94.1% 94.1% 94.1%94%

AHU RF Motor Size (hp) 30 30 30 30 120

AHU RF Motor Eff iciency 91.0% 91.0% 91.0% 91.0% 91%

AHU Motor Load Factor 30% 30% 30% 30% 30%

Hrs/Wk OA is Supplied: 28.0 28.0 28.0 28.0

28

4 hrs less run

time/day in summer,

7 days/w eek

Wks/Yr OA is Supplied: 12 12 12 1212

summer schedule is

12 w eeks long

Heating Balance Point (F): 55 55 55 55 55

TMY3 Night Heating Degree Hours: 0 0 0 00

No heating coil in

AHU

AHU on chilled w ater plant loop? Yes Yes Yes Yes N/A

AHU Discharge Air Temp: 55 55 55 55 55

Conversion Factor 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000

Chilled Water Used for Outside Air

Sensible Cooling (MMBtu/yr)75 75 75 75

See TMY3 Data Tab

for calculation

Chilled Water Used for Outside Air

Latent Cooling (MMBtu/yr)78 78 78 78

Chilled Water Used for Return Air

Sensible Only (MMBtu/yr)145 145 145 145

75°F Return air

based on BAS data,

unless economizing

Total Chilled Water Used

(MMBtu/yr)298 298 298 298 1,192

Ignore additional

cooling due to fan

energy

Average Chilled Water Rate $24.35 $24.35 $24.35 $24.35 $24.35

Chilled Water Cost (MMBtu based) $7,258 $7,258 $7,258 $7,258 $29,033

Schedule Reduction of AHUs 2, 3, 4, 5 on Summer Nights

Scheduling of AHUs

Currently AHU-2 through 5 run until 10p year round. This calculation estimates the savings of turning off the AHU's at 6p on summer weekdays and weekends, which better corresponds to the building schedule. This calculation includes savings from the following: AHU fan savings, AHU chilled water savings, fan powered box fan savings

and fan powered box reheat savings. Assume that AHUs do not need to kick on to meet setpoint temperature for at least the first 4 hours.


- 2012

6-4

Electrical AHU Fan Consumption

(kWh/yr)8,472 8,472 8,472 8,472

33,890

Average Electrical Rate ($/kWh) $0.080 $0.080 $0.080 $0.080 $0.080

Electrical Cost at the Fan $679 $679 $679 $679 $2,715

Number of FPVAV Boxes 264

Average FPVAV Motor (HP) 0.267

Fan Speed Setting Average

(Hi/Med/Low )0.75

Total FPVAV Motor HP 52.9

Total FPVAV Motor kW 39.4

Average FPVAV Motor Eff iciency 50%

FPVAV Fan Electrical Consumption

(kW/hr)26,502

FPVAV Fan Electrical Cost $2,123

Airf low reduction for spaces in heating

mode due to overcooling of air at Low

Occupancy (cfm)

40,000

Per Query of BAS

4/19-4/25

Defined as any zone

in low er half of

heating/cooling

setpoints is either

just in heating or w ill

be heating.

Temperature difference betw een

discharge air and neutral air (°F)15

Steam reheat savings (MMBtu) 218

Steam reheat cost savings

($/yr)MMBtu)$3,266

Total Annual Energy Cost $7,937 $7,937 $7,937 $7,937 $5,389 $37,136

Project cost Estimate $25 $25 $25 $25 $100

Incentive $0

Simple Payback 0.0 0.0 0.0 0.0 0.0


- 20126-5

FIM #2: AHU-2 through AHU-5 Duct Static Pressure Reset

Reduce Static Pressure for AHU-2, AHU-3, AHU-4 & AHU-5notes

AHU-2 through AHU-5

Supply fan motor power (HP) 300

Motor load factor 60.0%

Supply fan motor efficiency 95.0%

VFD efficiency 95.0%

VFD credit 0.5

Reduction of energy used compared to constant

volume system, based on IEEE study

Operating schedule (hrs/day) 17

Operating schedule (days/yr) 356

Current electricity consumption (kWh/yr) 450,229

Percent reduction from static pressure reset 15%

low end estimate based on ASHRAE and California

PIER studies

Electricity Savings (kWh/yr) 67,534

Electricty Saving from Fans (kWh) 67,534

Additional Steam for Heating (MMBtu/yr) -115

not clear why there would be additional steam,

AHU discharge 55°F regardless

Chilled Water Savings (MMBtu/yr) 115

Average electric consumption per ton (kWh/ton-hr) 0.90

Assume chillers have similar COP to campus

chilled water system.

Electricity Savings for Chilled Water (kWh/yr) 8,643

Opinion of Cost Notes

Functional Testing $5,000

Programming $3,000

Improvements in critical zone not included in this estimate

Total ($) $8,000

Incentive Calculation Notes

Total Electric Savings (kWh) 76,178

Electric Rate ($/kWh) $0.04270

Potential Annual Cost Savings ($) $3,253

Steam Savings (MMBtu) -115

Opinion of Project Cost ($) $8,000

Efficiency Partners Incentive ($) $4,747


- 2012

6-6

FIM #3: Demand Control Ventilation

For the purposes of the calculation, the following assumptions were made:

- The minimum outside air quantity is 35% of the unit total supply cfm

- The demand control ventilation would result in an average outside air quantity of 15% of design

- The occupancy sensor would results in the AHU running only 80% of the scheduled time

- The unit would be economizing when the outside air is between 70°F and 30°F, and therefore no

savings from the demand control ventilation would be achieved

- AHU-1 is scheduled to run during the school year from 7a-10p

- Return air is 70°F and discharge air is 55°F in cooling and 65°F in heating

725450 CEDAR RAPIDS MUNICIPAL AP

Removed summer break, one month for winter break, thanksgiving, weekends, 10p-7a

Supply cfm 11000

assummed design oa cfm 3850

demand control oa cfm avg 1650

supply fan and return fan kW 16 Total Total

5.72 106

Date (MM/DD/YYYY) Time (HH:MM) Day Hour Dry-bulb (F)

Cooling

delta T

Demand

Control

Sensible

Cooling

Heating

CFM

reduction

Heating

Savings

(Btu) kW-hr Savings

1/20/1999 7:00 4 7 19.4 0 0 2717 133807 7680

1/20/1999 8:00 4 8 19.4 0 0 2717 133807

1/20/1999 9:00 4 9 21.2 0 0 2816 133208

1/20/1999 10:00 4 10 23 0 0 2915 132224

1/20/1999 11:00 4 11 24.8 0 0 3014 130856

1/20/1999 12:00 4 12 24.8 0 0 3014 130856

1/20/1999 13:00 4 13 26.6 0 0 3113 129102

1/20/1999 14:00 4 14 28.4 0 0 3212 126964

1/20/1999 15:00 4 15 28.4 0 0 3212 126964

1/20/1999 16:00 4 16 28.4 0 0 3212 126964

1/20/1999 17:00 4 17 28.4 0 0 3212 126964

Demand Control Savings

See excel spreadsheet for continued data.


- 2012

6-7

FIM #4: Chilled Water VFD and Leaky Valves

notes

Pump Totals CWP-6

Motor Power (HP) 5 5

Motor Efficiency -- 89.5%

Weeks per year operating -- 30

Energy use with throttling valve (current) (kWh/year) 15,456

From HiSAVE VFD Energy Savings

Estimator 15,456

Energy use with VFD (kWh/year) 4,355

From HiSAVE VFD Energy Savings

Estimator 4,355

Savings (kWh/year) 11,101 11,101

Opinion of Cost Totals

VFD Installed cost (labor and materials) $3,465 RS Means 2007 Electrical Cost Data $3,465

Install cost per differential pressure sensor $0 RS Means 2008 Mechanical Cost Data $0

Tap for sensor $0 RS Means 2008 Mechanical Cost Data $0

Additional piping for sensor $0 RS Means 2008 Mechanical Cost Data $0

Engineering design $1,000 $1,000

Number of 3-way valves to replace 0 tbd

3-way valve conversion cost per valve (parts and labor) $0 tbd

Valve converstion total $0

Programming cost $300.00 Assumption: $300 per loop

Total $4,465

Add VFDs to CW Pumps and HW Pumps

CW Pumps

Valve leakage calculation: Chilled Water Billed Use per Month MMBTU

FY 03 FY 04 FY 05 FY 06 FY 07 FY 08 FY 09 FY 10 FY 11 4-yr avg FY 12 savings

June 1,295 713 905 1,069 902 1,201 1,070 1,197 1,057 964

July 1,858 1,790 1,094 1,233 1,386 1,140 1,186 1,189 1,202 1,373

August 1,669 1,324 956 1,148 1,229 1,318 1,316 1,118 1,230 1,126

September 1,422 940 1,022 938 705 1,025 860 991 879 780

October 494 546 519 569 503 609 661 465 654 504

November 453 287 349 387 332 353 410 441 436 370

December 272 710 324 335 330 329 342 405 375 363 223 140

January 180 166 187 324 285 426 267 334 370 349 105 244

February 223 165 167 225 244 359 282 367 195 301 75 226

March 384 292 249 283 456 431 406 246 273 499

April 912 420 547 563 427 529 448 648 321 -

May 713 735 596 661 792 668 1,034 770 640 -

FY Total 9,875 8,088 6,915 7,735 7,591 8,388 8,282 8,171 7,632 6,019 610

CDD 1253 995 771 1365 1154 1165 931 752 1025

Rate 11.6206$ 12.3760$ 14.1403$ 15.6673$ 18.3073$ 20.2583$ 20.3555$ 22.0007$ 24.3518$ 14849

Annual Cost 114,753$ 100,097$ 97,780$ 121,187$ 138,971$ 169,927$ 168,584$ 179,768$ 132,912$

Annual Eff iciency 838 635 73 70 485 1,066 1,180 (293)


- 2012

6-8

FIM #5: Modified Fan Powered VAV Sequences

Additional data used for this calculation is in the excel spreadsheet.

Savings for Alternate Sequence of Occupancy Sensor Controlled Fan-Powered VAV boxesNotes

Number of Spaces suitable for Occupancy Sensors 195 Total FPVAV boxes with Occ Sensor from BAS

Average FPVAV Motor (HP) 0.267 Weighted average based on boxes installed

Fan Speed Setting Average (Hi/Med/Low)0.75

Low=.5 Rated Power, Med=.75 Rated Power,

High = Full Power

Total FPVAV Motor HP 39

Average FPVAV Motor Efficiency 50%

Conversion Factor (kW/HP) 0.746

Current Fan Runtime (hr/day) 14 Average from BAS Trend

Days/Year 355 Building is shut down on holidays

Est. Current FPVAV Fan Consumption (kWh/year) 289,556

Percent of time during occupied mode that space is neutral & vacant 30% Per Query of BAS 4/19-4/25

FPVAV Fan Savings (kWh) 86,867

Design Supply Airflow to FPVAV Boxes (cfm) 200,000 Total based on schedules

Design Min Outside Airflow (cfm) 66,000 Total based on schedules and design temps

Total Design AHU Fan HP 420 AHUs 2-5, Supply+Returns

Annual Average Operating Speed 56% Per Trend Data from 5/6-5/9 when ON

Average AHU Fan Operating HP 72.5

Average Airflow to FPVAV Boxes (cfm) 112,695

Per Trend Data from 5/6-5/9 when ON and per

Query of BAS 4/19-4/25

Reduction of Airflow when FPVAV Boxes are scheduled occupied, in

neutral or heating mode, & vacant (cfm) 26,675 Per Query of BAS 4/19-4/25

Avg Airflow to FPVAV Boxes when Zones are occupied, neutral, &

vacant (cfm) 86,020

Reduction in VFD Efficiency, Motor Efficiency, and Fan Mechanical

Efficiencies from average operating speed. 80%

Average AHU Fan Operating HP with Zones occupied, neutral, & vacant

(HP) 41.8

Conversion Factor (kW/HP) 0.746

Hours/Day 14

Days/Year 365

Est. Current AHU Fan Consumption (kWh/year) 276,458

AHU Fan Savings (kWh) 117,227


- 2012

6-9

Hours OA>70°F and High Occupancy 748 High Occupancy defined as weekdays 7am-5pm

Hours OA>70°F and Low Occupancy 681

Low Occupancy defined as weekdays 5pm-11pm

and weekends 7am-11pm

High Occupancy Airflow Reduction (cfm) 14,000 Per Query of BAS 4/19-4/25

Low Occupancy Airflow Reduction (cfm) 50,000 Per Query of BAS 4/19-4/25

Economizer savings, 55°F<OAT<70°F (MMBtu) 450

Return Air Temperature when OA>70°F (°F) 75 Per Query of BAS

Discharge Air Temperature (°F) 55

Specific Heat & Conversion Factor (Btu-min/ft 3̂-hr-°F) 1.08

Chilled Water Energy Savings (MMBtu) 1,412.07

Average electric consumption per ton (kWh/ton-hr) 0.90 From Seamens RCx Report

Electricity Savings for Chilled Water due to reduction in airflow

(kWh/yr) 105,906

Total Occupied Hours when fans are on 5,840

Hours when OA>55°F 3,947

Percent of Fan Savings resulting in additional cooling savings 68%

Chilled Water Savings due to FPVAV boxes turned off when vacant

(MMBTU) 200

Chilled Water Savings due to AHU Fan cfm reduction when vacant

(MMBTU) 270

Electricity Savings for Chilled Water due to reduced fan energy

(kWh/yr) 35,298

Airflow reduction for space in heating mode due to overcooling of air at

Low Occupancy (cfm) 40,000

Per Query of BAS 4/19-4/25

Defined as any zone in lower half of

heating/cooling setpoints is either just in heating

or will be heating.

Airflow reduction for space in heating mode due to overcooling of air at

High Occupancy (cfm) 6,000

Defined as any zone in lower half of

heating/cooling setpoints is either just in heating

or will be heating.

Hours at Low Occupancy 3,230

Hours at High Occupancy 2,610

Temperature difference between discharge air and neutral air (°F) 15

Steam reheat savings at Low Occupancy (MMBtu) 2,093

Steam reheat savings at High Occupancy (MMBtu) 254

Total steam savings due to eliminate reheat for spaces that are

vacant (MMBtu) 2,347

Opinion of Cost Notes

Occupancy Sensors Tie-In Programming Cost $19,500.00 Assumed $100 per VAV

Total $19,500

Incentive Calculation Notes

Total Electric Savings (kWh/year) 345,297

Electric Rate $0.08000

Potential Annual Electrical Cost Savings $27,624

Electric Savings Eligible for Incentive (kWh/year) 345,297

Electric Rate $0.04270

Eligible Annual Electrical Cost Savings $14,744

Steam Savings (MMBtu) 2,347

Steam Rate $15.01

Potential Annual Steam Cost Savings $35,228

Opinion of Project Cost $19,500

Project Cost eligible for incentive $5,753

Efficiency Partners Incentive $0

Prescriptive Incentive NA

Project Cost after EP Incentive $19,500

Project Cost after Prescriptive Incentive NA $20 per OS, but must control >400 watts

Simple Payback before incentive (years) 1.3

Simple Payback with EP incentive (years) 1.3

Simple Payback with Prescriptive Incentive (years) NA


- 2012

6-10

FIM #6: Snow Melt Control Modification

Steam Savings from Alternate Snow Melt Control

Summary

Currently the snow melt system runs when the outside air is less than 40°F.

SEG proposes that the energy control center take control of the snow melt control, with input from the facilities staff.

It is proposed that the snow melt be turned on when the forecast predicts at least 1" of snow accumulation.

This calculation evaluated only the west side auditorium snow melt, there is another small snow melt system at the garage entrance that was not evaluated as part of this calculation

Calculation methodology

Steam consumption at increased dramatically in the winter months beginning in the winter of 2009.

This increase coincides with the start-up of a snow melt system used at the building entrances and steps at the West side auditorium entrance.

The difference in steam use before and after the implementation of the snow melt system normalized for weather is used to determine savings.

Steam Savings Calculation

hdd MMBtu hdd MMBtu hdd MMBtu hdd MMBtu hdd MMBtu hdd MMBtu

November 671 537 749 918 1088 633

December 771 773 1,650 1,764 2019 1,362

January 878 951 1,705 2,057 2358 1,606

February 964 887 995 1,576 1665 1,221

Total HDD 4373 3,284 4831 3,148 4779 5,099 4651 6,315 4693 7130 3806 4822

MMBtu/hdd 0.75 0.65 1.07 1.36 1.52 1.27

2007-2010 avg hdd 4496

normalized steam use 3,377 2,930 4,797 6,105 6,831 5,697

average steam use before snow melt (MMBtu) 3,701

avg. steam use after snow melt (MMBtu) 6,211

avg. yearly steam consumption from

snow melt system (MMBtu) 1,757

Steam Cost ($/MMBtu) $15

avg. yearly steam cost from snow melt

system ($/yr) $26,422

June 2011-May

2012

FY 11 FY 12

Before snow melt After snow melt

June 2006-May 2007

June 2007-May

2008

June 2008-May

2009

June 2009-May

2010

June 2010-May

2011

FY 07 FY 08 FY 09 FY 10


- 2012

6-11

Now need determine the reduction in runtime due to manual control and subtract this cost from the current control method cost.

Assume that snow melt must be started 48 hours before snow event and be run for 12 hours afterwards.

Assume staff can shovel when accumulation is less than 1"

Assume that each snow event is at least 48 hours from precedding snow event

from http://www.ncdc.noaa.gov/ussc/USSCAppController#PERIOD

Historical # of Days with snow greater than:

Trace >.1" >1"

November 1.9 1.3 0.7

December 3.2 3.9 2.3

January 3.7 4.6 2.6

February 3.1 3.5 2.2

Total Days with snow 11.9 13.3 7.8

Actual snow melt run time 23.4 days

# of days in Nov-Feb 121

# of days that outside temp was <40°F 105 days

Amount of time snow melt runs with

new control/

amount of time snow melt ran with old

control 22%

Steam Consumption (MMBtu) 392

Steam Savings (MMBtu) 1,365

Snow Melt Cost (new control) $5,888

Snow Melt savings relative to old control $20,533


- 2012

6-12

FIM #7: Domestic Hot Water Recirculation Pump Control

EXISTING Example

Feet of Pipe 200 1,200 estimated based on building size and hw fixture location

Diameter of Pipe, inches 1.5 0.75

Heat loss rate 25.2 8.0

Motor Hp 0.250 0.264 197 W pump

Motor Eff 66.0% 66.0%

Motor Load Factor 0.65 0.65

Pump Operating hrs/yr 8,760 8,706

% yr loses from pipes

help to heat the facility:25% 25%

Water heater Eff iciency 65.0% 80.0%

Conversion Factor 100,000 100,000

Conversion Factor 0.746 0.746

Avg heat loss th/yr 509 784

Average therm Rate $0.950 $1.504 This is equivalent to $15.04/MMBtu

kW 0.18 0.19

kWh/yr 1,577 1,654

Average kWh Rate $0.080 $0.043

Annual Energy Cost $610 $1,250

PROPOSED

Proposed hrs/yr 3,500 6,570 Assumme pump can be turned off 6 hours/day, 365 days/yr

Avg heat loss th/yr 203 592

kW 0.18 0.19

kWh/yr 630 1,248

Annual Energy Cost $243 $944

SAVINGSth/yr 306 192

kW 0.00 0.00

kWh/yr 947 406

Annual Cost Savings $366 $306

Project cost Estimate $375 $1,000

Incentive $0 $0

Simple Payback 1.0 3.3

Red triangles in the upper right corner means there is a comment explaining the cell.

These spreadsheets are meant as a rough est imate of energy use and savings potent ial. FOE nor its contractors can guarantee the results calculated by this tool.

For a reasonableness check, contact a Preferred Ally or your FOE Energy Advisor.

Circulation Pump Timer

Yellow cells indicate that information from your facility is required for calculations.

Service water heating systems often have pumps that circulate hot water through a facility to make sure hot water is quickly available at taps. Often these pumps run 24 hours a day 7days a week regardless of the operational status of the facility. Pumping hot water through the facility can lead to significant heat loss. By

installing a low cost timer, the pump can be turned off during facility unoccupied hours.


- 2012

6-13

FIM #16: Replace Classroom Incandescent Lights with LED’s

EXISTING Example Classroom

lighting

Lighting Type Incand Incand

Location Office Classroom

Number of Fixtures 6 86

Lamps per Fixture 2 1

Fixture Wattage 120 150

LF - Load Factor 0.95 0.95

Annual Operating Hours 1,350 1,000 light are on occ sensor so usage is not high


kW 0.68 12.26

kWh/Yr Use 918 12,260

Average kWh Rate $0.088 $0.043


PROPOSEDLighting Type CFL LED

Number of Fixtures 6 86

Lamps per Fixture 2 1

Fixture Wattage 30 30


kW 0.17 2.45

kWh/Yr Use 230 2,450


SAVINGSkW 0.51 9.81

kWh/Yr Use 688 9,810


Project cost Estimate $48 $7,500

Incentive $0

Simple Payback 0.8 17.9

Red triangles in the upper right corner means there is a comment explaining the cell.

These spreadsheets are meant as a rough est imate of energy use and savings potent ial. FOE nor its contractors can guarantee the results calculated by this tool.

For a reasonableness check, contact a Preferred Ally or your FOE Energy Advisor.

Yellow cells indicate that information from your facility is required for calculations.

Replace Classroom Incandescent with LED's

Appendices

Documents

Retro-Commissioning Final Report 8/17/2012€¦ · Retro-commissioning (RCx) is a systematic, documented process that identifies operational and maintenance improvements in existing