04/20/23 1

Unlocking the Secrets of HVAC

Nash-Rocky Mount Public Schools

04/20/23 2

Overcoming Obstacles and Barriers

• Have you heard this before ?

– We need to run the school all night to heat the building!

– The energy program will cause us to have additional complaints or problems!

– Its always been that way! Just ask Bubba!!• Maybe it’s time for a change!

04/20/23 3

Understanding HVAC

• Where do you start?– Your biggest user?, or highest KBTU per sq.ft.

rating in Portfolio Manager? Look at 50% to 75%.– Improve the comfort level for energy savings.

• Who can help? – ANYONE! -- Energy Consultants, Engineers,

mechanics, directors, teaching staff, vendors.• Are you a detective?

– Did you ask all of the simple or right questions ?

Understanding Your Current Energy Use

• Benchmarking through ENERGY STAR’s (EPA’s) Portfolio Manager allows you to:

– Compare one building against a national sample of similar buildings

– Compare all of your buildings of a similar type to each other

– Set priorities for use of limited staff time and/or investment capital

Portfolio Manager• Benchmark the energy use of all of your buildings –

receive an energy use intensity (EUI) and K-12 schools and office buildings can receive energy performance ratings on a 1-100 scale

• Track changes in energy use over time in single buildings, groups of buildings, or entire portfolios

• Track cost savings and CO2 emissions• Apply for the ENERGY STAR• Track water usage

Understanding Your Current Energy Use

http://www.energystar.gov/benchmark

OfficesK-12 Schools

HotelsSupermarkets

Hospitals

Retail Stores

Others include: Warehouse, Residence Halls, Courthouses, Medical Offices,

Financial Centers/Banks, and Wastewater Treatment Plants

Ratable Spaces in Ratable Spaces in Portfolio ManagerPortfolio Manager

ENERGY STAR for Buildings• ENERGY STAR qualified buildings use 35 percent

less energy than average buildings. • Nearly 5,500 buildings, including more than 1,100

K-12 schools, have earned the ENERGY STAR for energy efficiency.

Red Oak Middle Nashville Elem

04/20/23 8

Areas to look for savings

• Mechanical

– AHU’s

–Central Plant

–Heat Pumps

• DDC Software Logic

04/20/23 9

All the Pieces

• Do You have the missing piece of the puzzle?

• You must have equipment working correctly, time clocks working, and DDC Sequence of Operation correct.

Reports

PM

Data Loggers

?Filters

Energy Projects

Boilers

ChillersHeat

Pumps

04/20/23 10

HVAC Terms

• DDC – Direct Digital Control System– Lead/Lag, RH, CWS, HWS, OAT, Outdoor Temp

Resets, OSS Blocks, CSP, HSP SPC Temp

• Mechanical– AHU, Primary/Secondary Loop, Mixing Valve, Split

System, SEER, PM’s, Central Plant

04/20/23 11

Findings using Data Logging as a Tool

04/20/23 12

Mechanical

• AHU’s

– How often do units have PM’s performed?

• Filters, Belts, motors/pulleys, coils cleaned, valves, actuators, and circuit setters.

• Have you checked the H/W C/W Strainers, and are they clean?

04/20/23 13

Mechanical

• Central Plant– How often do Boilers, Chillers, Cooling Towers,

Heat Exchangers, and Pumps have PM’s performed and cleaned?

• Heat Pumps – How often do units have PM’s performed? – Filters, Belts, motors/pulleys, coils cleaned,

refrigerant checked

04/20/23 14

DDC Systems

• How long has it been since it was installed?– If over two or three years consider re-commissioning

the system.– Have you updated system logic to the best energy

efficient strategies?– The NC Energy Office will help pay for DDC Tune-

ups.

04/20/23 15

DDC Systems

• Problem 1 – The zone temps do not look the same as occupied / unoccupied times. – Johnson Control’s N-30, check your date, clock, and

UTC offset. For Eastern Standard Time it should be 300.

• Problem 2 – The building seems to start up too early.– Siebe / Barber Colman Network 8000, check your

site time and OSS block maximum start time.

04/20/23 16

DDC Systems

• Problem 3 – The zone temps are reported too cold during the day in the winter mode, but ok when mechanic arrives. (Is it the teacher ?)– Siebe / Barber Colman Network 8000, check your

default time and default set-point values. They should be slightly higher on cool or slightly lower on heat.

04/20/23 17

DDC Systems

• Logic– Do water source Heat Pumps start before system loop

is at operating temps?– Do you have more than one schedule for your site, and

if so, do you stage their start time?– Do you use Optimum Start/Stop and if so what is the

maximum start/stop allowed?– Do you have OA Temperature Resets to control

Building loop Temperature? (30-60 180-140)

04/20/23 18

Results using Data Logging as a Tool

04/20/23 19

Reporting as a Tool

Energy Use Graph - Monthly and Annual Trend for Nash Rocky MountSchools

Electricity Fossil Fuels Annual Trend

MB

TU

09/2003 thru 12/2007

0

5,000

10,000

15,000

20,000

25,000

09/03 12/03 03/04 06/04 09/04 12/04 03/05 06/05 09/05 12/05 03/06 06/06 09/06 12/06 03/07 06/07 09/07 12/07

04/20/23 20

Results of NRMPS Energy Program

• First Four Years– KHW Saved ---------------- 26,142,085– Cost Avoidance Savings -- $4,372,979

• The check that you don’t write

– Hard Dollars ------------------ $258,649• Money in the bank

– Billing errors found ---------- $180,655• Monitoring of your bills

04/20/23 21

Environmental Impact

The avoided emissions of 18,602 metric tons of Carbon Dioxide or:

Greenhouse emissions from 3407 automobilesCO2 emissions from 2,111,518 gals of gas consumedCO2 emissions from the electricity use of 2464 homes

for one yearCarbon sequestered annually by 4,228 acres of pine

forest

04/20/23 22

• Our program was started on 9/1/04.– By 12/31/06 we had 13 ENERGY STAR labeled

buildings.– By 11/15/07 we have 18 additional Energy Stars.– By 10/24/08 we have 20 additional Energy Stars.– This will bring our total to 51 awards at 22 different

sites.

ENERGY STAR Ratings

04/20/23 23

Summary

• Do you have an energy program?

• How is your HVAC maintained?

• Is your DDC system out of site, out of mind?

• Who monitors utility bills, usage, reporting, and troubleshooting?

04/20/23 24

Where to Get More Information

• www.educonenergy.com

• www.energystar.gov

• www.energync.net

• www.advancedenergy.org

• www.southface.org