FEDERAL ENERGY MANAGEMENT PROGRAM

Internet: www.eren.doe.gov/femp

Technology

Installation

Review

A case study on

energy-efficient

technologies

Prepared by the

New Technology

Demonstration

Program

identify impacts on occupant comfort. The controller

was developed by Digi-Log as a tool for reducing

energy consumption and lowering operating costs in

the lodging industry.

The primary functions of the controller are to 1) monitor the power supply of the HVAC unit (protect it from

high or low voltages), 2) respond to room temperature

extremes and/or an alarming smoke detector (by generating a phone call followed by an alarm code), and

3) enable remote programming and control of various

dial-up commands and functions. If a power interruption or brownout occurs, a programmable timer

delays power transmission to the unit after site power

is restored to prevent damage to the unit. Power to a

unit can be terminated indefinitely via dial up access

to the controller. If Temperature Control Mode is

selected, an air-conditioning unit would be powered

off if the room temperature was within the high and

low temperature setpoint limits. If the room temperature was not within these limits, the controller would

allow the HVAC to turn on to prevent damage to the

room. The room controller also can detect a smoke

alarm beeping. The controller will dial and beep if a

smoke detector is alarming or if the temperature in the

room is very hot or cold.

Background

In 1998, the commercial sector in the United States

consumed 32% of the total electrical energy, which

equated to 15.4 quads of energy during that year, and

by 2020, this figure is estimated to

increase to 18.2 quads (DOE/BTS

2000). HVAC accounts for 31.8%

of the total energy consumed in

the commercial sector. Packaged

HVAC systems make up 82% of

the HVAC equipment being utilized in the sector. The lodging

industry is 9% of the sector, and

its HVAC usage accounts for

30.8% of the total energy used by

the lodging industry. Phillips

Electronics’ laboratory tests of

Digi-Log controllers in an environment simulation room indicate

that energy savings ranging from

50 to 80% are possible during

unoccupied periods. A one-year

field evaluation of the controller

Demonstration and Evaluation of HVAC Controller

for Lodging Facilities

Field evaluation of hotel/motel through-the-wall HVAC systems supervisory controller

Introduction

This Technology Installation Review (TIR) presents

the demonstration test results of the Digi-Log

supervisory HVAC (heating, ventilation, and airconditioning) controller installed in a hotel/motel

setting. Described are the technology, installation

requirements, technology demonstration and performance, and energy-saving features. The demonstration was conducted by the Oak Ridge National

Laboratory (ORNL) and sponsored by the U.S.

Department of Energy’s Federal Energy Management Program (FEMP) under its New Technology

Demonstration Program.

Several potential energy-savings devices are available

for through-the-wall HVAC systems but independent

test data quantifying their savings are sparse. This

field evaluation and demonstration study quantifies

the potential energy savings and assesses the impacts

on occupants and staff of using a Digi-Log supervisory HVAC controller in lodging facilities. The supervisory controller operates according to the occupancy

status of each room in a hotel or motel.

The Digi-Log controller is a plug-in device installed

between a wall outlet and the room HVAC unit. Preliminary tests conducted by Phillips Electronics in

laboratory-simulated environmental conditions suggest that energy savings ranging from 50% to 80% are

possible in unoccupied lodging rooms employing

the controller (Fisher 1999). The field study objective

was to quantify and verify these estimates and to

DOE/EE-0273

Digi-Log controller (left), ORNL monitoring-DAS device (right)

No portion of this publication may be altered in

any form without prior

written consent from

the U.S. Department of

Energy, Office of Energy

Efficiency and Renewable

Energy, and the authoring national laboratory.

Office of Energy

Efficiency and

Renewable

Energy
2

After installation, Digi-Log Technologies

Inc. made several software and hardware

modifications to their units during the oneyear test period. Data downloads from the

24 ORNL-monitored rooms were conducted nightly and automatically using an

on-board, dial-out modem inside the monitoring device. The field study test at the

Music Road Hotel ended October 31, 2001.

The Power Controller Unit was developed

by Digi-Log Technologies Inc. as a tool

for reducing energy consumption and protecting the HVAC units in low and high

voltage situations, therefore lowering

operating costs in the lodging industry.

The primary functions of the Power

Control Unit are to 1) monitor the power

supply of the HVAC unit (protect it from

high or low voltages), 2) respond to room

temperature extremes and/or an alarming

smoke detector (by generating a phone

call followed by an alarm code), and 3)

enable remote programming and control of

various dial-up commands and functions.

was initiated in September 2000 at the

Music Road Hotel in Pigeon Forge,

Tennessee. A total of 163 controllers were

installed in suites and single rooms, and 24

of these locations were monitored. Data

downloads were conducted nightly and

automatically using an on-board, dial-out

modem inside the monitoring-DAS device.

The Music Road Hotel was the first test

site for the controller. A second test is

under way at Silver Surf Gulf Beach

Resort in Bradenton Beach, Florida,

which allows evaluation of the controller

in a more severe cooling-demand climate.

This TIR describes results of a field evaluation of the performance of a Digi-Log

supervisory HVAC controller. During the

test period, the HVAC energy consumption in the uncontrolled rooms averaged

2632.2 kWh monthly while in the controlled rooms it averaged 1684.6 kWh.

This equates to the uncontrolled rooms’

HVAC consuming an average of 947.6

kWh (56.3%) more energy than the units

in the controlled rooms monthly. Due to

intermittent inoperability of the controllers

and other energy loads (controllers controlled approximately 50% of the hotel’s

conditioned space), comparison analysis

of the energy cost over a three-year period

for the entire hotel does not reveal any discrete savings during the test period over

prior years.

Installation and Technology

Description

Digi-Log Technologies Inc. and ORNL installed Digi-Log Power Controller Units

and ORNL Monitoring units in Music

Road Hotel at Pigeon Forge, Tennessee, in

September 2000. A total of 163 Power

Control Units, one per room, and 24 ORNL

Monitoring Units were installed. Of the

24 monitored rooms, 12 reference rooms

were not equipped with Power Controller

Units. Since the hotel had various room

configurations (whirlpool tub, fireplace,

kitchenette, etc., see Figure 2), rooms with

controllers and reference rooms were

matched based on size and orientation.

FEDERAL ENERGY MANAGEMENT PROGRAM

Figure 2. Test Site (Pigeon Forge, Tennessee).
3

Setting, Room Heat Pump Enable), all

rooms are programmed. The front desk

clerk can now enter the Check In or Out

Status by choosing the Check In or Out

button on the Room Heat Pump Enable

menu as hotel guest checks in or out, as

shown in Figure 5.

If the temperature control mode is “on”

and the “unoccupied” mode is selected,

the HVAC unit will be powered off if the

FEDERAL ENERGY MANAGEMENT PROGRAM

A communication link via telephone

(computer modem or touchtone phone

keypad) is established between each

Power Controller Unit and the front desk,

using the in room phone line and a phone

line splitter. When a PC is used, Digi-Log

Technologies Inc. software and Host Interface Unit are required. A desktop PC is

located at the hotel front desk as shown in

Figure 3. When the software is activated a

dialog box appears that allows the user to

enter a password that determines the managers or the front desk clerks entry level.

This level permits programming and/or

modification of the Power Controller’s

parameters and dial-up commands (Setup Room Controller, shown in Figure 4).

After the manager has entered and completed Set-up (filling in the Room Check

In or Out, Room Parameters, and Modem

Figure 4. Digi-Log controller interfacing software initialization menu and

password menu.

Figure 3. Front desk computer at front desk, installed Digi-Log unit, uncovered Digi-Log unit.

room temperature is within the unoccupied high and low programmed temperature limits. If the room temperature is

above or below these limits, the Power

Controller Unit will allow the HVAC unit

to be activated to satisfy the temperature

limit setpoints.

If the Temperature Control Mode is “on”

and the “occupied” mode is selected, the

HVAC unit will be powered off if the room

temperature is within the occupied high

and low programmed temperature limits.

However, if the room temperature goes

below the low temperature limit or above

the high temperature limit the HVAC unit

will be powered on to maintain the temperature limits.
4

The winter or summer mode is automatically selected by the Power Controller’s

software and will change as outside temperatures dictate. However, at a guest’s

request the summer/winter mode can be

reversed or the temperature control mode

can be turned off giving the guest complete control of the HVAC unit.

In order for the Power Controller Unit to

function properly, the housekeeping staff

must make sure the HVAC unit is turned to

the “on” position as they leave the room. If

a power interruption or brownout occurs,

the Power Control Unit interrupts the

power supply to the HVAC unit. The HVAC

unit will not be reconnected until site power

has been restored and the programmable

time delay period has expired. This prevents

short cycling of the compressor and prevents restart load damage.

The Power Controller Unit will call a preprogrammed call-back number, generating

a dual-tone alarm code, if the temperature

in the room is more than 5 degrees above

or below the programmed high or low

temperature limits of the unoccupied

mode or if an in-room smoke detector is

alarming. The recipient of the call

acknowledges the alarm, causing the

alarm to cease. If the recipient hangs up the

phone without acknowledging the alarm,

the controller will immediately call back

and continue to generate the dual tone

alarm codes. After the alarm has been

acknowledged the alarm function will be

cleared allowing another alarm to occur.

ORNL Monitoring Method

and Device

The approach that ORNL took to carry out

the field evaluation study was as follows:

• Develop an instrumentation plan and

data acquisition (DAS) hardware.

• Identify test sites based on climate,

complex size and historical energy

consumption.

• Select rooms within complex for evaluation based on occupancy, exposure, orientation, and location within the complex

• Install controller and monitoring-DAS

devices (boxes beneath HVAC unit

shown in Figures 1 and 3),

• Monitor room conditions and HVAC

performance for one year.

• Use survey tools to determine impact

on occupants and hotel staff.

• Analyze system performance and publish findings.

In conjunction with Pace Scientific,

ORNL developed a monitor-DAS packaged device that was compatible with the

controller. It records 1) electrical current

to the HVAC unit, 2) room temperature,

3) room humidity, and 4) occupancy

status/wattage to the HVAC unit. A Pace

Scientific data logger was included in

the packaged device, which must be

preprogrammed using Pace’s software

prior to field installation. Data must be

entered into two menus—one to program

the device and the other to program the

host computer, as shown in Figure 6.

Data in spreadsheet format were downloaded from the 24 ORNL-monitored

rooms nightly and automatically using an

on-board, dial-out modem inside the

monitoring-DAS device. The device

facilitates collection of performance data

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Figure 5.Check-in or out, room parameters, modem settings, and executing (heat pump enable) menus.
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FEDERAL ENERGY MANAGEMENT PROGRAM

on the HVAC controller and is shown in

Figure 7. Spreadsheet utilities were used

to reduce and analyze data.

Energy-Saving Features and

Benefits

The supervisory controller operates

according to the occupancy status of each

hotel/motel room. The controller is a

plug-in device installed between a wall

outlet and the room HVAC unit. The

controller saves energy by allowing the

room temperature to float more than is

permitted by the room thermostat during

unoccupied periods and prevents the

room from overheating and overcooling

during occupancy.

Federal Sector Potential and

Technology Application

Since the primary functions of the room

controller are to: monitor power supplied

to an in-space HVAC unit, verify that no

power interruption or brownout occurs,

and enable supervisory control of the

HVAC system, the unit can be used on any

brand through-the-wall HVAC system. If

a power interruption or brownout occurs,

power to the unit is interrupted for a programmable amount of time after site

power is restored to prevent damage to the

unit. Power to a unit can be terminated

indefinitely via dial-up access to the

controller. If the room temperature is not

within the set limits (i.e., 55°F and 85°F),

the controller will allow the HVAC to

Figure 6. ORNL logger setup for monitoring-DAS device and host computer (right).

Figure 7. ORNL monitoring-DAS device.
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FEDERAL ENERGY MANAGEMENT PROGRAM

operate to prevent damage to the room.

The controller will dial and beep if a

smoke detector is alarming or if the temperature in the room exceeds programmed

set limits. The power interruption/brownout, HVAC controls, and smoke detector

notification can be used in any Federal

building that has in-space through-the wall

HVAC systems.

Cost and Installation

The HVAC controller is a plug-in device

installed between a wall outlet and the

room HVAC unit. The unit cost for the

power controller is $299, and the installation cost varies depending on the property.

Generally, the installation cost is between

$10 and $25 and is determined after a site

inspection. Currently, a desktop computer

that is located at the hotel front desk (seen

in Figure 2) is required, but software can

be incorporated into the hotel computer in

future applications.

Technology Performance

and Demonstration

Test Rooms Analysis

The yearly occupancy and energy use for

the hotel rooms with Digi-Log controllers

(controlled) and rooms without controllers

(uncontrolled) was determined from data

acquired by ORNL monitoring-DAS

devices. Data illustrated in Figure 7a

show that rooms equipped with controllers were occupied roughly the same

number of days as those without controllers except during December 2000 and

February through April 2001. The HVAC

energy consumption in the controlled rooms

is consistently less than that in the uncontrolled rooms. The uncontrolled rooms

HVAC energy consumption averaged

2632.2 kWh monthly while the controlled

rooms HVAC units averaged 1684.6 kWh,

which equates to the uncontrolled rooms

HVAC consuming an averaged of 947.6

kWh (56.3%) more energy than the units

in the controlled room monthly during the

test period. Figures 7b and 7c show the

averaged daily energy consumption per

HVAC unit monthly for the controlled and

uncontrolled rooms during occupancy

(temperature limits: 69°F minimumsummer, 76°F maximum-winter) and

vacancy (temperature limits: 83°F maximum-summer, 50°F minimum-winter).

When controlled rooms are occupied, the

daily averaged energy consumption per

HVAC unit ranges from 3.5 to 10.6 kWh/

day, averaging 6.7 kWh/day, as shown in

Figure 7b. Whereas during occupancy for

the uncontrolled rooms, the energy use

ranges from 5.5 to 14 kWh/day, averaging

8.8 kWh/day. On average, each HVAC

unit in the uncontrolled rooms consumed

Figure 7a. Energy consumption and occupancy of controlled and uncontrolled rooms.

Figure 7b. Averaged daily energy consumption per room (HVAC unit) during occupancy of rooms.

Figure 7c. Averaged daily energy consumption per room (HVAC unit) during vacancy

of rooms.
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FEDERAL ENERGY MANAGEMENT PROGRAM

32.1% more energy than those in the

controlled rooms during occupancy.

During vacancy, the uncontrolled rooms

HVAC units averaged daily energy use

per unit ranges from 3.5 to 13.6 kWh/day,

averaging 8.3 kWh/day as shown in

Figure 7c. When the controlled rooms

are vacant, the HVAC unit’s energy

consumption ranges from 2.7 to 10.2 kWh/

day, averaging 5.8 kWh/day. Each HVAC

unit in the controlled rooms consumed

43.1% less energy than the HVAC units in

the uncontrolled rooms when the hotel

room is unoccupied. During the test

period, there were not any significant comfort differences between the controlled and

uncontrolled rooms, indicating that the

controller did not compromise comfort.

Figures 8 through 15 reveal the comfort

conditions in both sets of rooms during the

winter (December 2000–February 2001)

and summer (June–August 2001) seasons.

During the winter season, the temperature

in the uncontrolled rooms falls primarily

within a 30°F band (50°F to 80°F) with the

relative humidity (RH) falling largely

between 25 and 70% (see Figures 8 and 9).

During the same season, as shown in Figures 10 and 11, the controlled rooms average temperature and RH ranged between

50°F–75°F and 30–70%, indicating that

there were any significant comfort differences between the controlled and uncontrolled rooms. During the summer season,

the monitoring-DAS devices were inoperative for about 4 weeks; therefore, the data

for this period are not shown in Figures 12

through 15. Analyzed data indicate that

uncontrolled room average temperature

and RH ranged primarily between 68°F–

80°F and 40–70%, while the controlled

room conditions ranged mainly between

69°F–80°F and 45–70%. The results show

that comfort conditions were very similar,

indicating that using the controller did not

compromise comfort.

Hotel Analysis

All hotel rooms were equipped with supervisory controllers (163 rooms, one per

room, excluding 12 ORNL-uncontrolled

rooms) for the duration of the test period.

The total energy impact on the hotel was

Figure 8. Room space temperature

for 12 uncontrolled rooms during

the winter season.

Figure 9. Room space relative humidity for 12 uncontrolled rooms during

the winter season.

Uncontroll ed Hotel Rooms Environme nta l Condi tion (December 2000 - February 2001)

0

10

20

30

40

50

60

70

80

90

100

11/25 11/30 12/5 12/10 12/15 12/20 12/25 12/30 1/4 1/9 1/14 1/19 1/24 1/29 2/3 2/8 2/13 2/18 2/23 2/28 3/5

Date

Temperature ( o F) 

Rm401 Rm602 Rm608 Rm609 Rm413 Rm416

Rm619 Rm620 Rm623 Rm624 Rm627 Rm628

Uncontrolled Hotel Rooms Environmental Conditions (December 2000 — February 2001)

Uncontroll ed Hotel Rooms Environme ntal Condi tion (Decembe r 2000 - February 2001)

0

10

20

30

40

50

60

70

80

90

11/25 11/30 12/5 12/10 12/15 12/20 12/25 12/30 1/4 1/9 1/14 1/19 1/24 1/29 2/3 2/8 2/13 2/18 2/23 2/28 3/5

Date

Relative Humidity (%)

Rm401 Rm602 Rm608 Rm609 Rm413 Rm416

Rm619 Rm620 Rm623 Rm624 Rm628 Rm627

Uncontrolled Hotel Rooms Environmental Conditions (December 2000 — February 2001)
8

Figure 12. Room space temperature for 12 uncontrolled rooms during the summer season.

Uncontroll ed Hotel RoomsEnvironme na l Conditions (June - August 2001)

0

10

20

30

40

50

60

70

80

90

100

5/24 5/29 6/3 6/8 6/13 6/18 6/23 6/28 7/3 7/8 7/13 7/18 7/23 7/28 8/2 8/7 8/12 8/17 8/22 8/27 9/1 9/6

Date

Temperature ( oF) 

Rm401 Rm602 Rm608 Rm609 Rm413 Rm416

Rm619 Rm620 Rm623 Rm624 Rm627 Rm628

Uncontrolled Hotel Rooms Environmental Conditions (June — August 2001)

Figure 11. Room space relative humidity for 12 controlled rooms during the winter season.

Controll ed Hotel Rooms Environmenta l Condition (December 2000 - Fe brua ry 2001)

0

10

20

30

40

50

60

70

80

11/25 11/30 12/5 12/10 12/15 12/20 12/25 12/30 1/4 1/9 1/14 1/19 1/24 1/29 2/3 2/8 2/13 2/18 2/23 2/28 3/5

Date

Relative Humidity (%)

Rm501 Rm502 Rm508 Rm509 Rm513 Rm516

Rm519 Rm520 Rm524 Rm727 Rm528

Controlled Hotel Rooms Environmental Conditions (December 2000 — February 2001)

Figure 10. Room space temperature for 12 controlled rooms during the winter season.

Controlle d Hotel Rooms Environme nta l Condition (December 2000 - February 2001)

0

10

20

30

40

50

60

70

80

90

100

11/25 11/30 12/5 12/10 12/15 12/20 12/25 12/30 1/4 1/9 1/14 1/19 1/24 1/29 2/3 2/8 2/13 2/18 2/23 2/28 3/5

Date

Temperature ( oF)

Rm501 Rm502 Rm508 Rm509 Rm513 Rm516

Rm519 Rm520 Rm523 Rm524 R727 Rm528

Controlled Hotel Rooms Environmental Conditions (December 2000 — February 2001)
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FEDERAL ENERGY MANAGEMENT PROGRAM

Figure 15. Room space relatively humidity for 12 controlled rooms during the summer season.

Controll ed Hotel Rooms Environme nal Condi tions (June - August 2001)

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

10 0

5/24 5/29 6 /3 6 /8 6/13 6 /18 6 /23 6 /28 7/3 7/8 7 /13 7 /18 7/23 7/28 8/2 8/7 8/12 8/17 8/22 8/27 9 /1 9 /6

Date

Relative Humidity (%) 

Rm50 1 Rm50 2 Rm50 8 Rm509 Rm513 Rm516

Rm51 9 Rm52 0 Rm52 3 Rm524 Rm727 Rm528

Controlled Hotel Rooms Environmental Conditions (June — August 2001)

Uncontroll ed Hotel Rooms Environme na l Conditions (June - August 2001)

0

10

20

30

40

50

60

70

80

90

100

5/24 5/29 6/3 6/8 6/13 6/18 6/23 6/28 7/3 7/8 7/13 7/18 7/23 7/28 8/2 8/7 8/12 8/17 8/22 8/27 9/1 9/6

Date

Relative Humidity (%) 

Rm401 Rm602 Rm609 Rm413 Rm416 Rm619

Rm620 Rm623 Rm624 Rm627 Rm628

Figure 13. Room space relative humidity for 12 uncontrolled rooms during the summer season.

Uncontrolled Hotel Rooms Environmental Conditions (June — August 2001)

Figure 14. Room space temperature for 12 controlled rooms during the summer season.

Controlle d Hote l Rooms Environmenal Conditions (June - August 2001)

0

10

20

30

40

50

60

70

80

90

100

5/24 5/29 6/3 6/8 6/13 6/18 6/23 6/28 7/3 7/8 7/13 7/18 7/23 7/28 8/2 8/7 8/12 8/17 8/22 8/27 9/1 9/6

Date

Temperature ( o F) 

Rm501 Rm502 Rm508 Rm509 Rm513 Rm516

Rm519 Rm520 Rm523 Rm524 Rm727 Rm528

Controlled Hotel Rooms Environmental Conditions (June — August 2001)
10

Figure 17. Monthly Heating Degree Day for Knoxville (October 1998–2001).

Figure 18. Monthly Cooling Degree Day for Knoxville (October 1998–2001).

Figure 16. Monthly kWh Usage of the Hotel (October 1998–2001)—(furnished by

Hotel’s CFO, Alvin Adams).

FEDERAL ENERGY MANAGEMENT PROGRAM

evaluated by comparing the kW usage on

the electricity bills over the last three

years. During the test period (2000/2001),

the kW usage was lower for seven of the

12 months (January–February, May, and

July–October) than the previous year

(1999/2000) during the same interval, as

shown in Figure 16. For the test period,

the hotel consumed 30395 kW (1.5%) less

energy than it used the previous year (1999/

2000). During 1998/1999, the energy usage

was higher five of the 12 months than that

consumed during the test period (2000/

2001), with comparable usage for March

and May. The small energy consumption differences are partially attributable to

1) the higher number of heating degreedays (HDD), shown in Figure 17, during

November 2000 through January 2001

than for previous years, 2) having supervisory controllers managing around 50%

of the hotel conditioned space, and 3) the

total hotel energy usage not only accounts

for the HVAC energy but also for energy

use of lighting and other electrical accessories and appliances. Each room is outfitted with a microwave, television, and

refrigerator. The 1998/1999, 1999/2000,

and 2000/2001 cooling degree-days

(CDD), cited in Figure 18, are roughly

within 50 CDD of each other during the

core-cooling season (June–August) and

appear to have minor differentiating influence on the energy usage. Table 1 shows the

calculated energy cost per HDD and CDD.

The averaged energy $/HDD is less during

the October 2000–2001 test period than that

of the previous two years. But the averaged

energy $/CDD is higher during the test

period than that of the previous two years.

Discussion and Conclusions

On average, each HVAC unit in the uncontrolled rooms consumed 32.1% more

energy than those in the controlled rooms

during occupancy. Each HVAC unit in the

controlled rooms consumed 43.1% less

energy than the HVAC units in the uncontrolled rooms when the hotel room is

unoccupied. The kW usage for the total

hotel was reduced by 1.5% over that of the

previous year. The rationale for dissimilar

energy reductions between the data results

for the 24 monitored rooms and that for the

entire hotel is that the controllers were

inoperative for several intervals of the test

period. Periods when controllers were not

functioning are delineated in Table 2.

Inoperability that incorporated all controllers was caused by power glitches, brownouts, and software/controller adjustment.

There was a direct relationship between

power interruptions and occupant complaints. Initially about 5 to 6% of the hotel

occupants complained after a power interruption. After modifying the software,

complaints were reduced to between 3 to

5%. Subsequent to making the first
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FEDERAL ENERGY MANAGEMENT PROGRAM

component change to the control board the

occupant complaints were reduced to

roughly 1%. Since the final circuit modification, there are no records of guest complaints. Random inoperability involving a

limited number of controllers was hotel

occupant, housekeeping, and/or maintenance

staff dependent. The controllers were

deactivated after room occupant complaints

about the HVAC system, thereby causing

inoperative intervals. The 12 monitored

controlled rooms device deactivations

were minimized, because the monitoringDAS units would not call in if they were

Table 1. $/HDD and $/CDD for Music Road Hotel (Knoxville, TN, climate data .

(1998 – 2001).

1998/1999 1999/2000 2000/2001

$/HDD $/CDD $/HDD $/CDD $/HDD $/CDD

Oct

Nov 16.49 23.45 16.70

Dec 14.97 13.38 10.46

Jan 11.78 10.87 12.11

Feb 15.14 17.79 14.14

Mar 14.17 21.16 13.85

Apr

May

Jun 34.62 33.65 45.19

Jul 28.91 30.98 27.98

Aug 27.31 30.77 28.33

Sep 56.11 51.47 64.42

Maximum 16.49 56.11 23.45 51.47 16.70 64.42

Minimum 11.78 27.31 10.87 30.77 10.46 27.98

Average 14.51 36.74 17.33 36.72 13.45 41.48

unplugged. Therefore, the status of the

controllers was checked daily. Also, the

controllers were inoperative when housekeeping or occupants turned the HVAC

unit off. The unit must be in the ‘on’

position to be supervised by the controller.

Manufacturers

Digi-Log Technologies, Inc.

600 Highway 61 East

Maynardville, Tennessee 37807

(888) 559-9498, (865) 599-5966

digilog@icx.net

Smart Systems International

3271 S. Highland Drive, #707

Las Vegas, NV 89109

(702) 734-0044, (800) 243-8762

fflower@smartsystemsintl.com

References

DOE/BTS 2000. BTS Core Databook

2000, “Commercial Sector Energy Data.”

U.S. Department of Energy (DOE), Office

of Building Technology, State, and Community Programs (BTS).

Fred A. Fisher. 1999. Environmental and

Product Design Study of Digi-Log Power

Controller #1. Philips Consumer Electronics Company, EMI/RFI/EMC Environmental Safety. Knoxville, TN. Table 2. Problems and inoperability of supervisory controller.

Date Problems, Complaints, and Modifications

Nov – Dec 2000 There were five to six complaints per month from occupants resulting from the staff’s unfamiliarity with operating the system.

& Jan 2001 Procedural problems occurred when front desk staff entered incorrect information (e.g., check out instead of check in, temperature

controller off rather than on). These problems were more prevalent during training of a new front desk member. There were fewer

complaints because there were few power interruptions.

Feb 2001 This was the first month that a brownout occurred; the HVAC units went off during the brownout and most came on when the proper

voltage returned. When there was a power outage of extremely short duration, approximately 5-6 percent of the units would not come

on when the power returned and maintenance unplug the controllers. The power was out three to four times (up to 30 minutes per

event) over a 12-hour period. No occupant complaints regarding the HVAC during the 12-hour period were received.

Mar – May 2001 During this period there were approximately 12 to 15 power glitches that resulted in 2 to 10 of the controllers having to

be unplugged by maintenance when interruptions occurred. Attempting to correct the problem of the HVAC not coming back on

after a brownout, the software was changed and the microprocessors were replaced in the controllers. These changes were made four

times, and each time the percentage of failures dropped but there were still HVAC units not coming on after a short power glitch.

The majority of the occupant complaints were limited to the units not coming back on after power interruptions and/or units not

coming on at initial check-in to room. Both problems were a result of the microprocessor not resetting.

June 2001 A circuit component problem on the control board of the controllers was discovered. The controllers were removed floor by floor, in

order to take them to the shop to be repaired. All of the controllers were repaired and reinstalled by August 2001. This appeared to

resolve the microprocessor reset problem that occurred during very short power interruptions.

Sept – Nov 2001 During installation of controllers in another hotel test site, a different circuit component problem was discovered. It was detected

because of the site uncommon transformer-wiring configuration. The total voltage of the power supply is 240 V across the line,

209 V on one leg and 107 V on the other leg. Assuming that this circuit component problem was contributing to the microprocessorreset problem at Music Road Hotel, the site controllers were reworked again. Controllers were removed two floors at a time

reworked and reinstalled. The modification was done from September through November 2001.
Disclaimer

This report was sponsored by the United States Department of Energy, Office of Federal Energy Management

Programs. Neither the United States Government nor any agency or contractor thereof, nor any of their employees,

makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness,

or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe

privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, mark,

manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by

the United States Government or any agency or contractor thereof. The views and opinions of authors expressed

herein do not necessarily state or reflect those of the United States Government or any agency or contractor thereof.

For More Information

FEMP Help Desk

(800) 363-3732

International callers please use

(703) 287-8391

Web site: www.eren.doe.gov/femp

General Contacts

Ted Collins

New Technology Demonstration

 Program Manager

Federal Energy Management

 Program

U.S. Department of Energy

1000 Independence Ave., SW, EE-92

Washington, D.C. 20585

Phone: (202) 586-8017

Fax: (202) 586-3000

theodore.collins@ee.doe.gov

Steven A. Parker

Pacific Northwest National

 Laboratory

P.O. Box 999, MSIN: K5-08

Richland, WA 99352

Phone: (509) 375-6366

Fax: (509) 375-3614

steven.parker@pnl.gov

Technical Contact

Evelyn Baskin

Oak Ridge National Laboratory

P.O. Box 2008, Bldg. 3147

Oak Ridge, TN 37831-6070

Phone: (865) 574-2012

Fax: (865) 574-9329

baskine@ornl.gov

Produced for the U.S. Department

of Energy, Office of Energy

Efficiency and Renewable

Energy, by the Oak Ridge

National Laboratory

DOE/EE-0273

July 2002

FEDERAL ENERGY MANAGEMENT PROGRAM

Printed on recycled paper with soy-based inks.

About FEMP’s New Technology Demonstration Program

The Energy Policy Act of 1992, and subsequent

Executive Orders, mandate that energy consumption

in Federal buildings be reduced by 35% from 1985

levels by the year 2010. To achieve this goal, the U.S.

Department of Energy’s Federal Energy Management

Program (FEMP) is sponsoring a series of programs

to reduce energy consumption at Federal installations

nationwide. One of these programs, the New Technology Demonstration Program (NTDP), is tasked to

accelerate the introduction of energy-efficient and

renewable technologies into the Federal sector and to

improve the rate of technology transfer.

As part of this effort FEMP is sponsoring a series of

publications that are designed to disseminate information on new and emerging technologies. New

Technology Demonstration Program publications

comprise four separate series:

Federal Technology Alerts—longer summary

reports that provide details on energy-efficient, waterconserving, and renewable-energy technologies that

have been selected for further study for possible

implementation in the Federal sector.

Technology Installation Reviews—concise reports

describing a new technology and providing case study

results, typically from another demonstration program or pilot project.

Technology Focuses—brief information on new,

energy-efficient, environmentally friendly technologies of potential interest to the Federal sector.

Other Publications—the program also issues other

publications on energy saving technologies with

potential use in the Federal sector.