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
Variable Capacity Heat Pump RTF Sub-Committee
February 22, 2012
Mira Vowles, P.E., CEM Emerging Technology Project Manager
BPA Energy Efficiency
Slide 1
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
Meeting Agenda
1. VC HP Sub-Committee Overview (Mira)
2. EPRI Lab Testing Results (Ron)
3. Request for PNW VRF project info (Mira)
If we have time:
– Discuss M&V best practice & standard protocol
Slide 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
VRF System Definition
Variable refrigerant flow (VRF) systems, either heat-pump
or heat-recovery styles, providing heating and airconditioning, and typically consisting of:
1. Outdoor unit(s) with inverter driven compressor(s) and
condenser fan providing improved part-load and lowambient performance,
2. Multiple indoor units with multi-speed fans, electronic
expansion devices, integrated zone temperature
controllers and no electric resistance heating capacity,
3. Refrigerant piping between the outdoor and indoor units,
5. Ventilation provided by either natural ventilation or a
dedicated outside air system (DOAS).
Slide 3
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
Office Building Definition
 A building used primarily for office functions, including
desk-work, reading and light equipment (computer,
copier, printer, telephone, etc.) use.
 Office occupancies are further defined by
 overall occupant densities between 50 and 300
square feet per person,
 overall lighting power densities up to 1 watt per
square foot, and
 overall equipment plug loads up to 1.5 watts per
square foot.
Slide 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
Building Simulation Program Issues
 Due to the complexity of VRF systems (both VRF HR
and VRF HP), building simulation programs are needed
to estimate site-specific savings;
 How can the accuracy of the building simulation
programs be verified?
 What are the important metrics?
 Monthly energy use and average monthly
temperature
 Other?
 Can building simulation programs provide these
important metrics for verification purposes?
Slide 5
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
VRF System M&V Best Practice?
– Meter baseline and VRF system electricity use for
representative period, project to annual savings
– Use calibrated Building Simulation model to predict
annual savings and monthly electricity use
– Verify savings by comparing actual monthly electricity
use to predicted monthly electricity use
Slide 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
VRF System M&V Standard Protocol?
– Use whole building regression analysis spreadsheet with
representative period pre- and post- monthly electricity
billing data and hourly average OSA temperature,
– if savings are temperature dependant, over 15% of
whole building electricity use and there are no other
significant changes to electricity use, the whole building
regression analysis spreadsheet can provide an 80-20
confidence interval for savings
Slide 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
Small Office Monthly Electricity Use and Savings
30,000
20,000
Monthly Savings (kWh)
15,000
Proposed (kWh)
10,000
Adj Baseline (kWh)
5,000
No
v
p
Se
l
Ju
ay
M
ar
M
n
0
Ja
(kWh)
25,000
Based on Energy Solutions EnergyPro model
Slide 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
Percent Monthly Electricity Savings
33% 32%
35%
(%)
33%
31% 31%
27%
30%
25%
30% 31% 32%
28%
25%
21%
20%
15%
10%
5%
0%
Jan Feb Mar
Apr
May Jun
Jul
Aug Sep Oct
Nov Dec
Based on Energy Solutions EnergyPro model
Slide 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
Use Whole Building Analysis for VRF ROB
Electricity Savings M&V?
– Energy Solutions EnergyPro model predicts monthly
electricity savings ranging between 21 and 33%
– For the Small Office (7,200 SF) the monthly electricity
savings ranging between 1,900 and 2,200 kWh
Next Step: use whole building regression analysis
spreadsheet, using EnergyPro model predicted monthly
electricity use and Seattle hourly average OSA
temperature
Slide 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
Send PNW VRF project info to Mira at
mkvowles@bpa.gov
– Project Name
– Location
– New or Retrofit?
– Other changes affecting electricity use?
– Building Type
– Baseline HVAC
– VRF Type (HP or HR)
– VRF System Size (tons)
– Baseline HVAC System Cost
– VRF System Cost ($)
– Date of VRF Cx?
Slide 11
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 Meeting: 3/28/12 at 9 am
Potential Topics:
– Compile list of PNW VRF installations & brainstorm how
to “mine” for useful information
– Develop M&V best practice and standard protocol
– Develop research plan to verify model accuracy
– Compare actual RTU annual fan kWh/SF to models
– Develop VRF savings estimates (IEER plus fan?)
– NEEA RTU Replacement Discussion
Slide 12