high performance or hype performance? some real world data · 2011. 4. 23. · actual building...

High Performance or Hype Performance? Some Real World Data

Marc Rosenbaum, P.E. South Mountain Company West Tisbury, MA

© Marc Rosenbaum, 2011

Welcome

NESEA is a Registered Provider with e American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certi"cates of Completion for non-AIA members are available on request. is program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to speci"c materials, methods, and services will be addressed at the conclusion of this presentation. © Marc Rosenbaum, 2011

is presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited.

© Marc Rosenbaum 2011

Copyright Materials


Learning Objectives

•  Participants will learn how well models conform with actual building performance

•  Participants will learn the value of sub-metering in diagnosing excessive energy usage

•  Participants will learn about how minisplit heat pumps and one ground source heat pump perform

•  Participants will learn how occupant behavior affects energy consumption

•  Participants will have some fun © Marc Rosenbaum, 2011

Before…

Bindley Residence A Net Zero Deep Energy Retro"t on Squam Lake NH


Aer… Garland Mills Timber Frames © Marc Rosenbaum, 2011

e owner was inspired by a session on Zero Net Energy Homes at Building Energy and wanted her renovation to be ZNE. However, Squam Lake is on the north side…and a steep hillside with trees is on the south, with Route 3 beyond. So the envelope is extraordinary, to compensate.

is is a second home with intermittent occupancy. When occupied it can be occupied by large groups. e "rst year the house was kept at comfort temperature to get data.

Sub-metering has enabled study of energy consumption by end use. © Marc Rosenbaum, 2011

Location Holderness, NH – Squam Lake Area ~3,500 ft2 includes conditioned basement Occupancy Intermittent; vacation home Foundation R42 walls, R20 slab Walls R52 Roof/ceiling R73 Windows R5+ Blower door results 330 CFM50 Mechanical system W-W GSHP, closed loop vertical; SDHW Metering Utility; PV; GSHP; DHW !


Strategies include: • Existing sheathing air barrier sealed with peel-and-stick tape. • Eaves cut off for AB continuity • Urethane foam stress skin panels on roof and walls - forms new overhang for the roof • Four inches of rigid foam over the existing slab, then Warmboard • Basement (mostly "nished) studded out, seven inches of closed cell spray foam • Walls and roof framing have additional closed cell spray foam • ermotech windows and doors, triple glazed with two low-e layers • Blower door results – 4,000 CFM50 reduced to 330 CFM50 • Renewaire EV130 ERV • WaterFurnace water-water ground source heat pump (GSHP), vertical closed loop ground connection, radiant %oor heat • 80 sf solar DHW system, designed so collectors heat the 80 gallon electric tank "rst then the 120 gallon preheat tank • 7.5 kW solar electric system • Meters on GSHP, DHW back-up, and PV output © Marc Rosenbaum, 2011

Collectors heat primary tank "rst, then solar tank © Marc Rosenbaum, 2011

• Meters are on the PV inverter output, the heat pump system input, and the DHW back-up input, as well as the utility meter. ere is also a water meter on the incoming water to the DHW system.

• Meters are read by the owner at varying intervals. © Marc Rosenbaum, 2011

is is a homemade spreadsheet that performs a monthly energy balance

Energy Model


Observations: • • Data is from 12/6/08 through 12/9/09 • • Intermittent occupancy • • Water meter mounted near ceiling facing upwards L

Energy Model Bindley House Data

Energy in kWh Model Actual Heating 2,766 2,360 Cooling --- --- DHW 1,127 626 Ventilation Included in other Included in other Lights/plug/other 3,600 2,497 Energy totals 7,493 5,483 DHW water, gallons !


•  • GSHP has been working very reliably and efficiently. Modest temperature li between closed loops at about 40F and heat storage tank at 95F, coupled with attentive design to minimize pumping power, have yielded a system that appears to be operating above a COP of 3.

•  • Back-up heating of the DHW tank was using more energy than expected – this was tracked to incorrect wiring of the electric elements in the primary tank and an excessive setpoint. Once corrected, this energy dropped to close to zero. Several months later, it jumped up again – this was tracked to a freeze rupture in one of the collectors. © Marc Rosenbaum, 2011

e Prototype Classroom and 1989 Wing A Deep Energy Retro"t at the Plain"eld, NH School


•  Prototype Classroom occupied Fall 2009

•  1989 Wing occupied Fall 2010

•  Windows are quad-glazed Serious Windows

•  Minisplits are Mitsubishi Hyperheat, rated to -13F

Location Plainfield, NH Area ~8,000 ft2 Occupancy K-8 Public School Foundation R15 slab edge Walls R45 Roof/ceiling R40 Windows R5+ Blower door results None Mechanical system Cold climate minisplit heat pump; ERVs Metering Heat pump; ERV; lights !


e Prototype Classroom integrates a Deep Energy Retro"t with distributed HVAC. It includes: •  Skirt the slab-on-grade with 3 inches foam insulation •  New quad-glazed Serious windows •  New or repaired sheathing used as the air barrier •  6-1/2 inches of added exterior rigid foam and new wood cladding •  Room-by-room HVAC - a residential energy recovery ventilator and a minisplit heat pump

e Prototype Classroom Fix


Gym

1972 building

1989 Addition

Prototype Classroom

Floor Plan


3” PerformGuard

3” Polyiso beneath 3-1/2” Nudura EPS panels with integral 1x nailers

SPF at eave

Windows in TimberStrand extension bucks


Indoor heat pump unit

Perforated fabric duct


• Renewaire EV200 energy recovery ventilator • 175-180 CFM as installed - 10 CFM/person • 151 Wattd • 85% effectiveness (measured at -3F outdoor air temperature and 70F indoor air temperature) • Demand controlled via CO2 • No tempering coil


Heat pump kWh

ERV kWh, elapsed time, run time

Indoor and outdoor temperature Relative Humidity

CO2

Also on-off for lights and ERV

Measuring...


Plain"eld School District voted 188-57 on March 6th, 2010 for a $275K bond to extend this to the rest of the 1989 addition – this work was performed Summer 2010


12 inch SIPs on %at roof plus tapered insulation


Structural upgrade © Marc Rosenbaum, 2011

Prototype Classroom Energy in kWh Model Actual Heating 757 Cooling Included in heating DHW --- Ventilation 184 Lights/plug/other 901 Energy totals 1,842 DHW water, gallons --- !•  is is based on data collected from January 8th through June 18th 2010 •  Heating and cooling energy use for the 8,000 2 wing from start of school in

Fall 2010 through January 28th, 2011 has been 4,393 kWh, during a period of 4,334 HDD65. Extrapolating to 7,800 HDD65 yields a predicted heating/cooling energy of about 7,900 kWh, or about 1 kWh/2/year.

•  It’s likely that total energy use in this wing will be less than 2.5 kWh/2/year •  A guesstimate of heat pump COP is 2 – 2-1/2. © Marc Rosenbaum, 2011

Margo Jones Architect

Bement School Residence Hall


Location Deerfield, MA Area 11,000 ft2 Occupancy 20 student dormitory and four faculty apartments Foundation R19 slab Walls R37 Roof/ceiling R60 Windows R4 Blower door results 1,490 CFM50 Mechanical system Minisplit VRF heat pumps; ERVs; SDHW; PV Metering Utility; PV; HP; DHW; DHW water; apartments !•  Four Mitsubishi 3 ton (most efficient) VRF air to

air heat pumps with 11 zones - 9 ducted units, 1 wall mount, and 1 %oor mount

•  ree energy recovery ventilators – one for each two faculty apartments and a 450 CFM unit for the dorm spaces

•  240 2 drainback solar thermal hot water system •  8.6 kW solar electric system


Envelope


Mechanicals


Meters


•  Forty 215W Sanyo solar electric panels and a Solectria inverter

•  Six Heliodyne Gobi solar thermal panels in a drainback con"guration with two Vaughn 120 gallon storage tanks


Energy Model


• is is extrapolated to a full year from 49 weeks of data. • I didn’t envision more than incidental cooling but a drawback to minisplit heat pumps is the ability to cool. e total energy into the heat pumps is measured but the split between heating and cooling is eyeballed from the data. Weekly heat pump energy for cooling exceeded weekly energy for heating! Using “dehumidi"cation mode” increased energy use.

• e solar hot water system has not yet operated properly, increasing energy use by thousands of kWh annually

• A guesstimate from early data is that the COP is in the 2-1/2 – 2-3/4 range.

Energy in kWh Model Actual Heating 11,267 12,442 Cooling None (duh) 10,231 DHW 7,002 13,281 Ventilation fans 6,700 (estimate) 6,700 (estimate) Lights/plug/other 17,300 21,655 Energy totals 42,269 64,309 DHW water, gallons 280 gpd 193 gpd !


• Eight affordable homes designed to be ZNE possible • 5.04 kW Sunpower solar electric panels • Single zone Daikin minisplit heat pump, wall unit in living room • Enerjoy electric radiant panels in each bedroom • Fantech 704 single speed HRV runs continuously, ~45 CFM • Marathon electric water heater • PVs are located on the roof to allow additional PV or solar DHW © Marc Rosenbaum, 2011

Envelope


Mechanicals


•  Meters are read monthly

•  HRV wattage at ~35W is too low to reliably read with these meters

•  Noticed a malfunctioning PV system (beware of 2-1/2 year olds…)

•  Currently have Hobo dataloggers measuring temperature and RH in all four of the three bedroom houses

•  Interesting to see variation in usage between houses

•  Having water meters on the DHW inlet and also kWh meter on the water heater allows calculation of energy used per gallon of DHW

•  e variation in how occupants use the single zone point source heat pump and the distributed electric radiant panels is interesting


is model predicts 5.9 kW needed for ZNE performance

Energy Model


•  Aer nine months, the total usage ranges from 4,539 kWh to 8,758 kWh

•  I predict two households will achieve ZNE and use less energy than the model, the rest will use more

Energy in kWh Model Actual Heating 1,451 Cooling --- DHW 2,673 Ventilation Included in other Lights/plug/other 2,700 Energy totals 6,824 DHW water, gallons 36 gpd !


Energy usage to heat water is about 0.20 kWh/gallon, with about a 75F rise – about a 0.90 EF


Marc Rosenbaum, P.E. South Mountain Company West Tisbury, MA

Thank You


high performance or hype performance? some real world data · 2011. 4. 23. · actual building...

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