WHAT IS THE DIGI- · DIGI-RTU ADDRESS ALL PNNL1 FOUR AREAS OF ROOFTOP UNITS ADVANCED CONTROLS 4640...
Transcript of WHAT IS THE DIGI- · DIGI-RTU ADDRESS ALL PNNL1 FOUR AREAS OF ROOFTOP UNITS ADVANCED CONTROLS 4640...
WHAT IS THE DIGI-RTU™
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
The Digi-RTU is a Heating, Ventilation, and Air
Conditioning (HVAC) rooftop unit control kit that
is both a demand management and energy usage
device. It is designed to improve the energy
efficiency and demand requirements of a rooftop
unit as well as solve the humidity, common
noise, and frequent on/off issues of a rooftop
unit through modulating the capacity of a rooftop
unit to match the cooling or heating space
requirements.
DIGI-RTU
PERFORMANCE RECOGNITION
American Public Power Association’s
2011 DEED Energy Innovator Award.
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
DIGI-RTU ADDRESS ALL PNNL1 FOUR AREAS
OF ROOFTOP UNITS ADVANCED CONTROLS
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
- Integrates air-side economizers
- Controls supply fan speed
- Controls compressor capacity
- Manages Demand-Controlled Ventilation, CO2
- Demand Response signal enabled
- Fault Detection via existing BAS, IP thermostat or utilizing Digi-SFT
1Department of Energy's Pacific Northwest National Laboratory http://www.pnnl.gov/main/publications/external/technical_reports/PNNL-20955.pdf
Addresses ALL Four PNNL Recommendations for Advanced Controls of Rooftop Units
HOW THE DIGI-RTU WORKS
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
By intercepting heating
and cooling calls, the
Digi-RTU’s patented
technology manages the
compressor and fan
speeds to match the
space requirements.
As a result space
temperature and humidity
are best managed. DIGI-RTU KIT
MAIN APPLICATIONS
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
– Package rooftop units, water and air
source heat-pumps, split units
– HVAC rooftop units between 3 to 30-ton
– Up to four cooling stages
– Up to two heating stages
– Scroll & reciprocating compressors
– Existing space thermostat and BMS
DIGI-RTU ADVANCED CONTROLS FUNCTION
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
Modulating mechanical HVAC equipment to better match space
operating requirements is the accepted industry standard
Modulating fan and compressor is the energy efficiency strategy for all
climate zones
Cool and hot/dry climates … increased free cooling
Cool and wet climates … humidity and moisture control
Economizer Integration
Integration and management of the existing economizer
Extends existing economizer range by 30%
Fan Speed Control
ON mode - average fan savings are greater than 85%
AUTO mode - average fan savings are 70 – 80%
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
Demand Controlled Ventilation, CO2
CO2 sensor into the return air duct integrated with the
economizer satisfies ASHRAE 62.1 and CA Title 24 air quality
requirements
Fault Detection
Digi-SFT provides fault detection diagnostics and notification
or
Digi-RTU communicates with the existing BAS or IP enabled t-
stat for diagnostics and notification
Demand Response
The Digi-RTU is subordinate to the existing T-stat or BAS
system responding to all space /building cooling and heating
requirements
The load-limit factor for the rooftop unit is sent through the
BAS to the Digi-RTU, and can range from 50-100%
DIGI-RTU ADVANCED CONTROLS FUNCTION
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
DIGI-RTU ADVANCED CONTROLS FUNCTION
Existing Building EE Strategies, Platform & Equipment
Communicates with existing BAS platforms and existing installed
thermostats; programmable, IP etc.
Integrates with the original equipment HVAC controller
Mounts inside the HVAC rooftop unit
Compressor Optimization
Conforms to original equipment manufacturer recommendations
for speed reduction down to 45Hz
Programmed logic provides soft start & stop of the compressor
Extended compressor life and lowered lifecycle costs
Compressor modulation savings are double fan power savings
for a significant portion of the United States climate zones
Peak Demand savings of 4 – 5kW for an average 10-ton rooftop
BENEFITS OF USING A DIGI-RTU OPTIMIZER
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
For Utility Companies: – Lowers peak demand up to 65%
– Reduces kWh usage up to 65%
– Decreases carbon emissions
– Scalable, 3-hour install time
For Building Owners and Tenants: – Reduces electricity consumption and costs
– Better maintains space humidity and temperature which decreases comfort complaints
– Reduces compressor on/off cycling up to 75%, and reduces maintenance cost
– Reduces HVAC equipment noise in occupied space
OMAHA, NE
DIGI-RTU CASE STUDY –
PHARMACEUTICAL DISTRIBUTION CENTER
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
70% kW
decrease
-20
0
20
40
60
80
100
0
10
20
30
40
50
60
70
80
90
100
9/18 10/18 11/17 12/17 1/16 2/15 3/17 4/16 5/16
OA
T (
F)
Po
we
r (k
W)
Date
Without Digi-RTU With Digi-RTU OAT
Measured Power Consumption and Ambient Temperature
Pre - blue
Post - red
Ambient temperature
5-minute intervals
DIGI-RTU CASE STUDY –
PHARMACEUTICAL DISTRIBUTION CENTER
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
85% kWh
decrease
Pre blue
Post red
5-minute intervals 0
10
20
30
40
50
60
70
80
90
100
30 40 50 60 70 80 90
Po
wer
(kW
)
OAT
Without Digi-RTU With Digi-RTU
Comparison of Measured Power Consumption with and without Digi-RTU
SAN DIEGO
DIGI-RTU CASE STUDY – OFFICE SPACE
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
February - March 2014
43% kW decrease
Measured RTU Power for One Minute Interval
Pre blue line Post green line Ambient temperature red line
DIGI-RTU CASE STUDY – OFFICE SPACE
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
February - March 2014
71% kWh
decrease
Pre blue line Post green line
Daily Electrical Energy Consumption; Pre (blue ) and Post (red ) vs. Ambient Temperature
SAN ANTONIO TX
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
SEPTEMBER – OCTOBER 2012
BIG BOX RETAIL
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
Two weeks with
and two weeks
without
29.5% kW
decrease
0
10
20
30
40
50
60
70
80
90
100
0
1
2
3
4
5
6
7
8
8/2
78
/28
8/2
98
/30
8/3
19
/19
/29
/39
/49
/59
/69
/79
/89
/99
/10
9/1
19
/12
9/1
39
/14
9/1
59
/16
9/1
79
/18
9/1
99
/20
9/2
19
/22
9/2
39
/24
9/2
59
/26
9/2
79
/28
9/2
99
/30
10
/11
0/2
10
/31
0/4
10
/51
0/6
10
/7
OA
T, D
eg
F
kW
Before
After
AVG-OAT
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
kWh
9/23/12 (OAT = 78 F; weekend; after install)
9/26/12 (OAT = 80 F; weekday; after install)
9/9/12 (OAT =79 F; weenkend; before install)
9/11/12 (OAT = 79 F; weekday; before install)
DIGI-RTU INSTALL ASHRAE #2
BIG BOX RETAIL
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
Two days with and
two days without
74% kWh
reduction
VERMONT
BURLINGTON ELECTRIC – STUDY Office Building
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
kWh
Metered Savings = 65%
W/O Digi-RTU
With Digi-RTU
65% kWh reduction
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
- Equipment sub-metered
- Two weeks pre
- Two weeks post
- IPMVP
0
20
40
60
80
100
4-Aug 9-Aug 14-Aug 19-Aug 24-Aug 29-Aug 3-Sep 8-Sep
Avg
. O
AT
Date
Without Optimizer With Optimizer
EFFICIENCY VERMONT - STUDY Distribution Center
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
kWh
Metered Savings = 68%
W/O Digi-RTU
With Digi-RTU
68% kWh reduction
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
- Equipment sub-metered
- Two weeks pre
- Two weeks post
- IPMVP
0
10
20
30
40
50
60
70
80
20
-Se
p
22
-Se
p
24
-Se
p
26
-Se
p
28
-Se
p
30
-Se
p
2-O
ct
4-O
ct
6-O
ct
8-O
ct
10
-Oct
12
-Oct
14
-Oct
16
-Oct
18
-Oct
Avg
. O
AT
Without Optimizer With Optimizer
DIGI-RTU CONCLUSIONS
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
Digi-RTU is able to:
– Reduce peak demand up to 65%
– Reduce consumption up to 65%
– Improve room humidity management
– Improve room temperature management
– Reduce compressor cycling
– Reduce maintenance costs
– Reduce equipment noise
4640 South 59th Street | Omaha, NE 68117 402.502.2340 | bes-tech.net
Bes-Tech, Inc. 4640 S 59th Street Omaha, NE 68117
402.502.2340
BES-TECH.NET