Post on 12-Jan-2016
BPA RTU Winter OperationPresented to:
RTUGAugust 2010
Presented by:Kathryn Hile, The Cadmus Group
Howard Reichmuth, New Buildings Institute
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Winter Analysis Overview
Improvements to analysis template
Downloading and organizing data
Fan operation – schedules
Gas pack operation
Heat pump operation
Winter economizing (or cooling)
Additional opportunities
Lessons learned
2
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Winter Sample
45 serviced RTUs
– 32 at 3 sites in Puget Sound area
– 13 at 3 sites in Tri-Cities area
4 baseline RTUs in Tri-Cities: serviced spring 2010
3
RTU Type Number of Units Subtractions Units Analyzed
All Electric 1 1
Gas Pack 34 5 29
Heat Pump 10 0 10
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Analysis Template Improvements
All winter data in one spreadsheet (at hour level) Much smaller analysis files Automation with SAS and VBA Time series dynamic graph Both SA min and SA max plotted in time series
4
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
5
Downloading and Cleaning Data HOBOlink
Excel
Visual Basic
SAS
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Data Preparation Process
Download zip file from HOBOlink with data from all HOBOs
Organize by HOBO Create one file for each HOBO, based on power,
one sheet for each two-week period Import to SAS with keys for CT size, WattNode
scale factor, fan low and fan high
6
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Data Preparation
Calculate hourly and daily minimums, maximums, totals and averages
Export to Excel Only full 24 hour days used to create energy
signature View data in hourly compressor map, dynamic
time series and energy signature
7
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Data Collection Issues
Some (not many) sensors failed last winter, and four sites required troubleshooting to fix– Splitters– AC adapter – battery failure
Downloaded data– One site: two units had nonsensical data– One site: three sensors just disappeared from
HOBOlink – result of the AT&T upgrades last fall?
8
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Calculating Percent Outside Air
9
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Winter Operation
Schedules – fan ON or AUTO
Fan kW, duty, base load
Typical signatures
10
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Fan Mode = ON Winter numbers similar to pilot data
11
Winter Data Summer Pilot Post-Servicing DataRTU Fan kW Fan Duty Base Load Fan kW Fan Duty Base Load
RTU6 0.69 91% 15.11 0.65 88% 13.68 HP15 0.65 100% 15.66 0.63 100% 15.06 HP17 1.40 100% 33.51 1.48 87% 30.96 GP5 0.96 99% 22.90 0.87 96% 20.13 GP6 2.69 99% 63.73 2.63 99% 62.53
AC10 0.89 100% 21.38 0.92 100% 22.19 AC6 2.66 38% 24.13 2.94 25% 17.42
RTU1 1.49 99% 35.28 1.46 93% 32.82 RTU3 0.93 100% 22.35 0.91 94% 20.35 RTU6 1.73 40% 16.43 1.73 35% 14.43
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Fan Mode = AUTO Small sample Fan kW very close; fan duty and base load differed
12
Winter Data Summer Pilot Post-Servicing DataRTU Fan kW Fan Duty Base Load Fan kW Fan Duty Base Load
RTU5 1.84 76% 33.48 2.12 85% 43.40
RTU3 2.06 5% 2.68 2.01 28% 13.50
HP2 0.60 8% 1.20 0.69 100% 16.45
GP7 1.28 26% 7.86 1.29 61% 18.71
GP8 1.35 2% 0.76 1.23 14% 4.07
AC9 1.22 5% 1.46 1.22 100% 29.31
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Signatures
24 of 32 energy signatures were as expected 8 needed more investigation to understand
performance
13
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Typical Signature 1
14
0 10 20 30 40 50 60 70 80 90 100 1100
10
20
30
40
50
60
70
80
90
Energy Signature
Average Daily Outside Air Temperature (F)
To
tal
Da
ily
En
erg
y (
kW
h)
Operates same set schedule each day
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Compressor Map
Same RTU as previous slide
15
10 20 30 40 50 60 70 800
0.5
1
1.5
2
2.5
3
3.5
4
RTU Hourly Avg kWh and Max kW
RTU2_Hourly_kWh_Graph RTU2_Max_Hourly_kW_Graph
Average Hourly Outside Air Temperature (F)
Ho
url
y k
Wh
an
d M
ax
kW
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Time Series
16
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Typical Signature 2
17
0 10 20 30 40 50 60 70 80 90 100 1100
20
40
60
80
100
120
Energy Signature
Average Daily Outside Air Temperature (F)
To
tal
Da
ily
En
erg
y (
kW
h)
Operates slightly longer at lower temperatures
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Compressor Map Same RTU, compressor map
18
0 10 20 30 40 50 60 70 80 90 1000
1
2
3
4
5
6
7
RTU Hourly Avg kWh and Max kW
RTU2_Hourly_kWh_Graph RTU2_Max_Hourly_kW_Graph
Average Hourly Outside Air Temperature (F)
Ho
url
y kW
an
d k
Wh
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Typical Signature 3
19
0 10 20 30 40 50 60 70 80 90 100 1100
20
40
60
80
100
120
140Energy Signature
Average Daily Outside Air Temperature (F)
To
tal
Da
ily
En
erg
y (
kW
h)
Two signatures – Monday – Saturday, and Sunday Unit may have reached setback temperatures when average daily
temperatures below 40
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Gas Pack Findings
Fan power calculated this winter was close to metered pilot data in almost all cases
Fan duty was close to metered pilot data in units with fan scheduled ON
Fan duty and base load were difficult to predict from summer metered data when fan ran in AUTO mode
20
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Winter Heat Pump Operation
Heat pumps were trickier Smaller sample, all at a notorious site Units served either offices or fabrication
(manufacturing) spaces Four units did not have economizers
21
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Heat Pump Typical Operation Energy increases as temperatures decrease Steeper slope than for cooling
22
0 10 20 30 40 50 60 70 80 90 1000
10
20
30
40
50
60
70
80
90
Energy Signature
Average Daily Outside Air Temperatures (F)
To
tal D
aily
En
erg
y (
kW
h)
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Heat Pump Compressor Map Same unit as previous slide
23
0 20 40 60 80 1000
5
10
15
20
25
RTU Hourly Avg kWh and Max kW
HP15_Hourly_kWh_Graph HP15_Max_Hourly_kW_Graph
Average Hourly Temperature (F)
Ho
url
y E
ne
rgy
(k
Wh
)
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Heat Pump Time Series
24
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Heat Pump Findings
Typical heat pumps will have a second sloped line
Need summer data (spring was not warm enough) to connect winter and summer usage
Will use that to calculate and predict total annual energy use, not just cooling and fan
25
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Winter Economizing Some units modulate dampers to take advantage of free cooling. SA min and SA max track OAT Three speed fan?
26
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Heating to Economizing Fan operates at different power when heating or
economizing
27
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Atypical Performance
Balance point below the range of monitored temperatures
Cooling at low temperatures Units serving the same space Two units with bad data
28
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Low Balance Point
29
0 10 20 30 40 50 60 70 80 90 100 1100
20
40
60
80
100
120
140
160Energy Signature
Average Daily Outside Air Temperature (F)
To
tal D
aiy
En
erg
y (
kW
h)
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Cooling at Low Temperatures
Mechanical cooling at 25 degrees
30
0 10 20 30 40 50 60 700
2
4
6
8
10
12
RTU Hourly Avg kWh and Max kW
GP6 Hourly kWh GP6 Hourly Max kW
Average Outside Air Temperature (F)
Ho
url
y kW
h a
nd
kW
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Cooling at Low Temperatures
31
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Heating a.m., Cooling p.m. Two different max kW, at 3.5 kW, cooling (SA min
at 55) and heating 4.5 kW (SA max at 90)
32
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Someone’s Been in my RTU…
33
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
…Twice!
34
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Economizer Findings
Cooling at temperatures below 40 degrees. Why? Controls? Or dampers didn’t modulate because broken? Bad sensor? Comments? Significant savings opportunity?
Cooling in the 50-60 degree F. Could economizer changeover temperature be increased for additional savings?
Winter is a good (better than summer?) candidate for economizer savings
35
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Preliminary Annual Signature
Winter:– Standard, flat gas pack– Standard, sloped – but could we just take an average
and keep slope at 0?– Gas pack with two occupancy schedules– Heat pump – is this signature messier than it would be
during summer cooling? TBD.
Atypical.
36
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Ex: AC w/Elect Resistance Heating
37
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
AC Compressor Map
38
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
AC Time Series
39
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Next Steps in Research
Draft annualized savings methodology with separate characterizations of annual operation for summer and winter
Data block interval analysis Recommendations regarding fan schedule persistence Additional persistence analysis Measure life implications from the data Updated M&V protocol recommendations
40
B O N N E V I L L E P O W E R A D M I N I S T R A T I O N
Web-Enabled Thermostats
Test the web-enabled thermostat as an M&V tool as a substitute for data-loggers– Data-friendliness?– How complete is it?– What does it look like?
Use the current analysis protocol and modify it for these data
41