Fluke 43B Case Studies

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Application Note

Energy savings

make the case for

an HVAC upgrade

Profile: Mike Klingler, Service Mgr.,

Farber Corporation

Tools: Fluke 1735 Three-Phase

Power Logger and Fluke 975

AirMeter™ test tool

Measurements: Energy consumption,

air quality

From the Fluke Digital Library @ www.fluke.com/library

Business needs: An older six-story building requires

cooling even in winter. To condition the air, a 200-ton

refrigeration unit operates year round, consuming major

amounts of energy. The client wants to reduce HVAC

energy usage without increasing the temperature.

Solution: Service contractor Farber Corp. measures

energy usage and air quality. Tests show that installing

a heat exchanger and shutting down a 200-ton chiller

during winter months will save the building owner $9,954

in annual energy costs.

Tools used: The Fluke 1735 Power Logger measures

energy consumed by the chiller. The Fluke 975 AirMeter

tester measures indoor air quality before and after the

installation to verify system performance.

Field

Applications

Case

Study

2 Fluke Corporation Energy savings make the case for an HVAC upgrade

Klingler had a plan in mind,

but didn’t want to guess how

much energy the big chiller

was consuming. The return on

investment (ROI) for his system

optimization program would

hinge on energy savings.

The law building uses hot

water heating and chilled

water cooling, with a dual-duct

system for air distribution. Hot

and cold air travel to termi-

nal units (also called mixing

boxes) which mix flows to

the required supply tempera-

ture. Water chilled to 45 °F

is pumped to the air handler,

where it cools supply air. In

the process, excess building

heat is transferred to the water,

warming it to about 55 °F. That

warmer water then returns to

the chiller, where it is cooled

back down to 45 °F and

pumped back through the loop.

In the original configuration,

the chiller used the refrigera-

tion cycle to transfer the waste

heat to another water loop on

the condenser side. Condenser

water at about 85 °F was then

pumped through rooftop cooling

towers that rejected the heat

into the outside air.

Taking the guesswork out

“What if I figure another way to

cool the system?” Klingler asked

himself. There was plenty of

cold air available outside during

the Columbus winter, where

temperatures average 33.5 °F in

December, 28.3 °F in January,

32 °F in February and 42 °F in

March. Klingler figured he could

bypass the chiller entirely.

We can use the water from

the cooling towers on the roof,

he reasoned, to cool the chilled

water. Instead of running the

chiller, why not use the cooling

towers to cool the condenser

side water down to 45 °F, and

simply pump it through a plate

and frame heat exchanger to

extract waste heat from the

chilled water loop? Instead of

Cool it: There must be a

better way

It was a familiar challenge for

Mike Klingler, service manager

for Farber Corporation, an

HVAC/R contractor in Columbus,

Ohio: Prove to a customer that

investment in a major HVAC

system upgrade would pay for

itself in energy savings, without

compromising occupant comfort

or indoor air quality (IAQ).

“I work in all kinds of build-

ings,” says Klingler, “and I

am often asked to reduce the

energy costs of the HVAC

systems.” The subject this time

was an older six-story build-

ing that once housed an insur-

ance company, but now serves

students at a Columbus-area

law school.

Working on a project to

replace two outdoor cooling

towers and install variable-

frequency drives in the build-

ing’s HVAC system, Klingler

noticed that one of the facility’s

two big 200-ton capacity chill-

ers was kept running to supply

cold water for the system, even

in winter.

“A lot of buildings we can

cool with outside air,” Klingler

says. “When we get down to

50-52 °F and below, we can

just draw that outside air in

and use it for free cooling. But

because of the setup of the law

school building, they had to run

one of the chillers even when it

was 20-25 °F outside. Because

of the duct distribution system

we couldn’t rely on outside air

in certain areas of the building.”

As a result, one chiller kept

running to supply water chilled

to 45 °F to the air handling

units and keep the building’s

occupied spaces comfortable.

The big motors powering the

device were consuming a lot

of energy and money—power

and cost the school could save

if Klingler could find a better

way to cool. Of course the

solution would have to deliver

acceptable indoor air quality.

the chiller’s powerful compres-

sor motors, the system would

run with just a small pump. The

cost of the upgrade would be

significant, but Klingler felt he

could prove it financially with

accurate data on the potential

energy savings. (see illustration)

Finding the ideal balance

between building energy

consumption and indoor air

quality requires a careful

balance of multiple factors. “One

of the areas we look to are

ventilation rates for the build-

ing,” Klingler said. “Decreasing

ventilation rates may reduce

overall energy consumption

and reduce operating costs, but

at the same time we have to

maintain good indoor air quality

standards too. There’s usually a

very tight ventilation standard

that the service provider has

to control in order to reduce

energy costs and maintain

quality indoor air conditions.

Considering the dynamic

changes in a building and a

functioning HVAC system, in

many cases, it’s not real easy.”

3 Fluke Corporation Energy savings make the case for an HVAC upgrade

But Klingler was well

equipped to find the balance

point. He could measure

multiple IAQ factors before the

upgrade, then check afterward

to ensure air quality was not

compromised, using the Fluke

975 AirMeter™ test tool. And he

didn’t have to estimate energy

consumption, or guess. He

logged actual kWh consumption

at the chiller over multiple 12-

hour cycles, using a beta test

version of the new Fluke 1735

Power Logger.

“I’m saying okay, I have to

run that 100-horsepower motor

in the winter time,” Klingler

said. “What’s the real kWh?

Then I can go back to the

owner and say, here’s how

much is it costing us to run

that chiller. The Fluke 1735

will measure and monitor over

time and tell me the real power

consumption of that equipment.

It takes the guesswork out of

it. Before having the power

analyzer, you would have to

say well, it’s probably consum-

ing about this much power. But

you can set this tool up and

walk away, then come back

and get the information. You

can see what your real power

consumption is for any equip-

ment in your building, and then

equate that to real dollars.”

Proving in the payback

Klingler’s measurements with

the Fluke 1735 showed that the

big chiller averaged 790 kWh

of power consumption over a

12-hour period. He computed a

total power consumption over

the four cold-weather months

of 189,600 kWh. At a cost of

six cents per kWh, running that

chiller was costing the law

school $11,376 every winter.

Klingler figured his alternate

approach would cut that bill

by 87.5 percent, for an annual

energy saving of $9,954.

He estimated that installing

the heat exchanger, piping,

valves and controls would

cost $46,000. That meant the

payback period for the project

would be just 4.62 years. And

that estimate did not include

possible savings due to reduced

wear and tear on the chiller

unit.

While he’s waiting for a

response on his proposal for a

system upgrade, Klingler has

found lots of other uses for the

Fluke 1735 and the 975 AirMe-

ter. Beyond simply measuring

power consumption, the Fluke

Power Logger collects all kinds

of power quality information

that Klingler figures will help

him do his job. And the AirMe-

ter makes it a snap to calcu-

late percentage of outside air

required to meet standards.

Working on a one-floor

remodel in a ten-story office

building, Klingler had to calcu-

late the percentage of outside

air delivered to a newly laid

out conference room. “We go

to ASHRAE 62 and the local

building code, and they say 15

percent of the air delivered to

the space needs to be outside

air,” he said. “How do you know

that 15 percent is really outside

air? You have to go back to the

big air handler, take a reading

and say, how’s this air handler

set up right now? What’s the

percentage of outside air we’re

providing to the entire build-

ing?

“With the 975 AirMeter, the

service company can go right

into the air handler and take

those readings and it will tell

us, based on temperature or

carbon dioxide. It’s a very quick,

easy, labor-saving tool.”

On the power quality side,

the Power Logger measures

voltage on three phases and

current on three phases and

neutral. It records multiple

parameters that can help deter-

mine system load, including

voltage, current, frequency, real

power (kW), apparent power

(kVA), reactive power (kVAR),

power factor, and energy

(kWh). It can also perform

power quality measurements.

And the Fluke 1735 downloads

to a PC and comes with soft-

ware for creating reports.

Cooling

Tower

Heat Exchanger

Load

Basin

Heater

(Optional)

CWP CHWP

Evaporator

Comp.

Condenser

Figure 1. Proposed new system with heat exchanger.

4 Fluke Corporation Energy savings make the case for an HVAC upgrade

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Fluke. Keeping your world

up and running.®

A more savvy contractor

“The power logger makes it

real easy for the contractor or

engineering group to come in

and measure power consump-

tion on individual components

in a building, a plant or an

industrial facility,” Klingler

said. “When you start to look

at the individual components,

it allows you to think in terms

of control strategies: how can I

control this piece of equipment

to reduce energy consumption?

How much is it costing me and

what can I do for savings?”

Beyond such applications,

Klingler sees the Fluke 1735 as

a tool that can help him move

his business to a higher level.

“For a mechanical contractor

such as myself, you’re adding

service offerings through the

use of this product,” he said. “It

allows you to be a more savvy

contractor. It allows you to be

more advanced and offer the

additional services that I think

we should be providing to our

customers. You can export the

data to spreadsheets, which

you can use for presentations

to the building owners. That’s a

big feature when I sit down at

the table.”

In addition to measuring

power consumption, as Klingler

did at the law school, the Fluke

1735 measures and logs volt-

age, amps, frequencies, wave-

forms, harmonics and power

anomalies. “For maintenance

and servicing, it’s a trouble-

shooting tool,” Klingler said.

“You can see if you’re having a

problem with power, or when

you’re not sure what’s happen-

ing and you can’t see it with a

snapshot from your meter. You

can measure it, record it and

view it with this device.

“As a contractor, I would use

it as a diagnostic tool, and it

would be just as valuable to

me in that regard as it is as a

power consumption tool. I can

use it both ways.”

Tips for optimizing your HVAC system

1. Measure airflow

Use duct traverses to measure air pressure,

velocity and flow. If pressure is too high and/

or airflow too low, check dirty coils, fans and

filters that could be blocking the system.

2. Check ventilation

Many buildings are either under-ventilated

(bad IAQ) or over-ventilated (expensive).

Readjust to ASHRAE standards.

3. Add VFDs

Variable air volume systems use variable

frequency drives (VFDs) to more efficiently

regulate motors and pumps. An upfront

installation cost in exchange for long term

energy savings.

ASHRAE 55 and 61

Guidelines for creating comfortable,

affordable, indoor environments

ASHRAE Standard 55, “Thermal

Environmental Conditions for Human

Occupancy”, explains how to create an

indoor environment that satisfies 80

percent of a building’s occupants. You

do it with a combination six factors: air

temperature, radiant temperature, air

speed, humidity, metabolic rate, and

clothing insulation.

Similarly, ASHRAE Standard 62,

“Ventilation for Acceptable Indoor Air

Quality”, lists the minimum ventilation

rates and air quality parameters that are

acceptable to occupants. It also explains

how to use ventilation to control air

contaminants.

Combined, the two standards provide

a set of thresholds for you to compare

customer systems against. Optimize

toward ASHRAE and you’ll probably

improve both air comfort and energy

usage.