danny parker sf lecture presentation
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Zero Net Energy at Homewalking the Talk
Danny Parker
May 2012
2
My House: Cocoa Beach, FL• 1500 ft2 with pool built in 1958• CBS construction: totally
uninsulated• Standard home of this type uses
about 20,000 kWh/yr• Millions like these in FL• Started retrofits after moving
in: 1989– R19 ceiling insulation– Removed carpet for tile floor– Dropped pool pump to 4 hrs/day– Sealed ducts following summer
3
Pools are big!• Second largest end-use in
homes that have them (4000 kWh/yr)
• Ready design solutions– Larger piping/low friction filters– Two-speed pumps
• Potential to cut by 70%• Solar pumping cuts peak
energy end-use ETAEngineering.com
4
CFLs, ventilation, WH Fan, Washer, Dishwasher…it goes on
5
Solar control low-e windows, wall insulation, mini-split heat pump …
6
Real-time Feedback & Monitoring
7
4.1 kW of PV : January 2009• Produced 6,542 kWh over year• Produced 99% of power used • Added 800 Watts in Nov.• Used 155 total therms • New plan: insulate walls,
replace windows• Install ductless SEER 26 mini-
split HP and ditch AC & ducts• Close to zero net
8
Not everything was helpful- (energy wise)
9
Done
10
How much did it cost?• Natural Replacement so
incremental only– White metal roof: $4000– Sealed ducts/insulation: $400– PV pumped pool: $3600– Ventilation fans: $500– Whole House fan: $300– CFLs everywhere: $400– Solar hot water: $2000– TED/Isole: $500
• PV: $30K less $9K tax credit & (possibly) $16K state rebate
• Total: ~$32 K over 20 yrs• Saves ~$2600/yr vs. avg use
Wanted Anyway: Tile floors, gas cooking, Flat screen TV, new dishwasher, new washer,
new AC, new refrigerator
11
Why stop there?• New Chevy Volt• Gasoline since late
September: 0.7 gallons• Electricity: 6.0 kWh/day• 25-30 miles a day; no gas• Saves $2.50 a day• Gas: $0.14/mi• Electric: $0.04/mi
Look Mom, no Utility Bill…• No bill! FPL paid me• Even with the car• Avg. Floridian spends
$2,000 a yr. on utilities and $1,500 on fuel for the primary car. $300/month
• I spend that money on coffee shops, movies and local restaurants….
14
Jobs Now? New Jobs?
15
Contentment…your own personal zero energy Life of Riley
Mini-split Heat Pumps for Retrofit Cooling Applications
Danny ParkerSouthface Institute
May 20121
Overview• How they work• Technology• Potpourri of data on
cooling• Room temperature
variation• What we know; what
we don’t (e.g., zoning)
3
How do they work?• Outdoor unit connected to indoor unit by
direct refrigeration line (no duct losses)• Mini-split: Zoned control of space• Multi-splits: Up to four units can be placed
inside• Multi-splits are generally less efficient, but
can reduce the number of outdoor units
Mini-Split Technology• Not new! Millions in use
in Asia/Europe• Small size; ideally suited
to low-e homes• Inverter controlled DC
compressor speeds• Higher efficiency• Variable speed blower• Electronic expansion vs.
TXV; hi-tech defrost 4,000 – 24,000 Btu/hr
Very High Efficiency Inverter Controlled Heat Pumps
Usage Profile 1 Total 7-day Usage~ 7 kWh!
NEEA Ductless Heat Pump Study in the PNW: Ecotope
NEEA’s NW Ductless Heat Pump Project www.nwductless.com
LW4
Slide 6
LW4 I edited to give credit to NEEA and include websitelwigington, 10/23/2011
Total 7-day usage ~ 26 kWh!
LW25
Slide 7
LW25 Danny - this is the same site - two different weekslwigington, 10/23/2011
SMUD Experience• Good
savings• But some
reliabilityproblems
• Some aestheticissues 0
200
400
600
800
1000
1200
1400
1600
May, 2011 June, 2011 July, 2011
kWhEstimated JeanElectricity vs. Actual ElectricityUse
Estimated Pre RetrofitElectiricty Use
Estimated RetrofitElectiricty Use
Actual Electiricty Use
Actual Kwh is 38% < estimated existing,but20% > than predicted
LW24
Slide 8
LW24 Proof reader recommends eliminating word "but" in 2nd bullet - I defer to you.lwigington, 10/23/2011
Ward Lutz Experience• Fujitsu 9RLS• 575 ft2 bungalow• Built in 1950• Western Ohio• Now super-insulated• Used 2-3 kWh per
day for cooling with temps above 90º F
Most cooling loads from internal sources
LW5
Slide 9
LW5FYI - You may want to indicate that is one of frst homes to meet the THC, and now, with addition of PV is net zero, He met THC priorto adding DHP or PV.
Ward did not think he would need AC, but house summer interior temps were higher than pre-retrofit (even with low baseload). He added DHP this past winter for heating and summertime cooling and dehumidification.
One of issues is trapping internal gains - other is that he is no longer ground coupled - he isolated the crawl space from the house -
Link to case study is inserted in notes below - I need to add recent data.
lwigington, 10/23/2011
O’Neill House• No compromise Passive
House in Sonoma, California• 2,400 ft2: super insulated;
super tight (0.38 ACH @ 50Pa)
• Mitsubishi Mr. Slim mini-split HP
• Low-energy cooling• But little cooling in Sonoma
(est. use 225 kWh/yr)
Data: Jeremy Fisher and Brennan Less, Energy Performance of Buildings Group, LBNL
LW6
LW7
Slide 10
LW6 ONeill is spelled with 2 lls
They refer to their project as Passive House, not PassivHaus on project websites
I added ACH 50 - feel free to delete if you think it adds too much clutter - super tight means many different things to different people
I added reference to LBNL under temp graph and on next 2 slideslwigington, 10/23/2011
LW7Recommend last bullet change to( est. use 225 kWh/yr.) (i changed - LW)Proof reader recommends eliminating word "but" from last bullet - I defer to you.lwigington, 10/23/2011
O’Neill House (monitored kWh)
Jeremy Fisher and Brennan Less, Energy Performance of Buildings Group, LBNL
Summer Operation: Comfort
O’Neill Passive House: June 17 -22, 2011
Jeremy Fisher and Brennan Less, Energy Performance of Buildings Group, LBNL
13
My House: Cocoa Beach, FL• Built in 1958• 1,500 ft2 with pool• CBS construction: totally
uninsulated• Typical energy use for this
housing type ~20,000 kWh/yr• Millions like these in Florida• Started retrofits after moving
in: 1989– R19 ceiling insulation– Removed carpet for tile floor– Dropped pool pump to 4 hrs/day– Sealed ducts following summer
LW10
LW11
Slide 13
LW10 CBS is very common term to FL - but may not be known to folks where CBS is not common. recommend spelling outlwigington, 10/23/2011
LW11 Is 20,000 kWh.yr total household energy or just electricity? ClarifyDoes standard home of this type use about 20,000 kWh.yr? I changed wording - Make sure my change is OKlwigington, 10/23/2011
14
Scads of Retrofits• Solar hot water with
tankless gas backup• PV DC pumped pool• White metal roof• Sun pipe interior lighting• Low energy refrigerator
15
CFLs, Ventilation, WH Fan, Washer, Dishwasher…It Goes On
Long-term Electricity Consumption• Utility records
since 1989• Big drop with early
conservationmeasures
• Steady for a decade although adding 50% floor area & two more people!
• Zero in 2011
Utility & Retrofit History for Parker FamilyCocoa Beach, 1989 - 2011
Year: 1989 - 2011
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Mon
thly
kW
h
-400
-200
0
200
400
600
800
1000
1200
1400
1600
1800 Monthly Electricity Consumption 12-month moving average
R19Ceiling& tilefloor
SealDucts WHFan
& new Frig
WhiteRoof
PV PoolPump
NewAC
EnergyFeedback
4.1 kWPV
Remodel
SolarDHW& Gas
CFLs
Flat Screen& DVR
* *Sarah Wade
FPL Average Use: 17,207 kWh/yr or 1,434 kWh/month
+500 ft2
Zero Electricity Objective
Add2nd Frig
ES CeilingFans ES Dish-
washer& WHF
ESWasher
Add0.8 kWPV
HiEffWindowsWall Ins.& Minisplit
ES KitchenFridg
AddFreezer
RemoveFreezer
Very High Efficiency Mini-split• SEER 26 mini split• Heat Pump
– HSPF= 12.0
• 9,000 Btu/hr output• Abandon duct system
Very High Efficiency Mini-split• Operate for space heating
rather than natural gas • Outdoor unit on west side of
house• Very quiet operation• Only 196 kWh for space
heat for all of 2010-2011• Mini-split power was about
the same as blower power on gas furnace!
Variation in Room-to-Room Temperatures• Used HOBO loggers
to evaluatetemperature variation
• Note wide temperature spread during heating season
• Even without space conditioning, lots of variation
• Impact of closing off rooms
Summer Operation: Power
Contrast Mini-split with Central System
--- Condenser--- Air Handler---Mini-split
LW13
Slide 20
LW13 I used text box to increase readability of keylwigington, 10/23/2011
Summer Operation: Comfort
Contrast Mini-split with Central System
--Thermostat Temp--Thermostat RH--Living Room Temp--Living Rooms RH--Tile Temp
LW14
Slide 21
LW14 I inserted text box to increase readability of keylwigington, 10/23/2011
Energy Reduction from Using Mini-split• Cooling energy July 3-9
with Central System:– 20.7 kWh/day (3.5 kWh/AHU)
– Interior temp: 79.1º F– Ambient: 82.0º F (75.8-91.5 )
• Cooling energy July 10-16 with Mini-split:– 8.9 kWh/day– Interior temp: 79.3º F– Ambient: 82.3º F (73.8 – 93.6)
• 57% savings, even though hotter in post period
www.infomonitors.com/dpr
----Condenser----Air Handler----Mini-split
LW
Slide 22
LW16 I Used text box to make key bigger -
lwigington, 10/23/2011
Summer Operation: Power
Contrast Mini-split with Central System
----Condenser----Air Handler----Mini-split
LW
Slide 23
LW17 I inserted text box to make color key biggerlwigington, 10/23/2011
Contrast Mini-split with Central System
Mini-split with Central Fan
How to Equalize Room Temperatures? • Multiple mini-split heads• Circulation fans
(Panasonic Whisper Green ceiling insert fans)
• Use existing air handler to circulate air• Consider low energy
AHU motor (Concept 3)• Small customized
interior ducts, as Dave Robinson will show…
Cost• Mini-splits: $2,500 - $4,000
installed per unit• $1,000 + for multiple heads• Multi-split with multiple heads
tend to be ~20% less efficient• Cost often reflects efficiency• Cost for one mini-split per
bedroom is similar to central system
• May be less if duct system does not exist, however
• How many are really needed?
LW19
Slide 27
LW19 I would change" 3,500" to $4,000 - $4,000 is very common - $2500 is pretty exceptionally low.lwigington, 10/23/2011
State of Knowledge• What we know…
– Best efficiency mini-splits can cut cooling needs by 30%-70%
– Hi-SEER with quiet operation– No duct leakage, conduction
• And what we don’t…– What are zoning savings?
• 1985 GRI study showed zoned heat savings of 31% in 25 PA homes
– What are room temperature distribtions compared w/central?
– Peak load of multiple systems? Single distributed?
Can a single mini-splitprovide efficient cooling option for hottest days?
LW21
Slide 28
LW21 Maybe add something about disribution needs could differr if goal is reduction of latent vs sensible loadlwigington, 10/23/2011
Conclusions: Mini-split Hi-efficiencyAdvantages:
– Millions in use worldwide!– Very quiet operation– Efficiency > SEER 20– Fractional ton sizes– No duct losses (leakage/
conduction) = 20% reduction– Zoning = 20% less energy– Good RH control– Easy to retrofit (no ducts)– Good retrofit for window
units & central systems
LW23
Slide 29
LW23 I think it is important to add that they work very well on partial load - efficiency goes up
Also that they could also substantilly reduce heating vost/ loads too with either expensive fuel or inefficient system
lwigington, 10/23/2011
Conclusions (cont.)• Distribution is important
– One mini-split per bedroom?– Really needed? One per floor?– Distributed single systems?– Enhanced by good
insulation/windows
• Disadvantages:– Expense similar to central– Condensate for each head– Some don’t like appearance of
indoor & multiple outdoor units)– U.S. AC trade may discourage
LW22
Slide 30
LW22 Under disadvantages maybe add something about ratings not reflecting true performance.lwigington, 10/23/2011
Zero Net Energy Homes for the Southeast
Key Takeaway Points: New & Existing
FLORIDA SOLAR ENERGY CENTERA Research Institute of the University of Central Florida
Danny ParkerSouthface Institute, May 2012
Success in a NutshellCut total electrical loads to 25 kWh/day
Tall order, but that’s successThink less house, more efficiency: McMansions: Just say No.Existing: Insulate what you can; optimize at time of replacement
Analyze utility bills to isolate heating/cooling costsAdd 5 kW PV system with inverterUnderstand that the cost effectiveness of everything follows from the cost effectiveness of PV systemEffective solar water heating system: tankless gas auxiliarySolar control measures to reduce coolingWell insulated building to reduce heating loads; use fully condensing gas for auxiliaryEfficient appliances: refrigerators, dishwashers, washers, TVsReal time Energy feedback to guide success
Floors for ZEH
Tile floors are best in hot climates; free cooling, half a ton in early summer
Use throw rugs for comfortSeasonal adjustments
Use R-5 perimeter insulationCrawlspaces: R-19 floor insulationExisting Homes: consider tile or wood in cooling climates when re-flooring
Walls for ZEH
Variety of solutionsMinimum R-11 insulationInspectedAdvanced framing/insulated headers
Existing: Spider® system for framePerformance IR inspection in winter/summer peak
R5 to R6 exterior sheathing is importantConsider for existing if re-siding
Choose light pastel paint color in hot climates
Windows for ZEH
High performance solar control windowsNon-metal framesSHGC <0.31U-factor < 0.35 Btu/hr/sqft-F.
Choose above at time of window replacements; otherwise not cost effectiveAttempt to orient more to south; fewer to the west– particularly in hot locationsGlass to floor area ratio 15% or lessMinimum 2 ft overhangs on south; 3 ft is better
Ceilings for ZEH
R-38 insulation; R-49 in cold climatesAdvanced framing
Add to above levels for existingInspected for consistency
Consider IR camera for existingUse insulated recess cansDucts buried in insulation if in atticInsulate over garage in hot climates
Roof for ZEH
Hot climates:Prefer light colored tiles or cool metalRadiant barrier underneathLight colored metal is a good choice
Existing: Make appropriate choices at time of re-roof; otherwise not cost effectiveIf insulated roof deck then consider at least R-30 with light colored tile
Well sealedConsider that roof pitch strongly influences performance
Duct System
Strongly prefer ducts in conditioned space under insulated ceiling
10% influence on heating& coolingContained in false ceiling
Otherwise:Buried in deep ceiling insulationUnder sealed attic with roof deck insulationDuctless heat pumps: great for new and existing
Ducts should be well-sealed and testedPrefer round duct to flex duct= lower friction and fan power
Cooling System
Consider NightBreeze system or other whole house fan or economizer system in mild dry climate (e.g. San Jose)Consider sizing for adequate moisture removal in humid climatesAuxiliary AC should have minimum SEER 15Consider advanced systems: SEER 19+ and HDAC systemsConsider ductless mini-splits for existing; solves two problems; very high performance
Heating System
Fully condensing gas furnace (92%+)Or utilize tankless gas heater with hydronic loopGeothermal ground loop system may not provide expected performance!
Beware pump powerMini-split heat pumps are very efficient, eliminate duct losses and provide zoning
Refrigerator
Most efficient refrigerator of the size and type you can findExisting: Measure your refrigerator energy use over a day long period. If it uses more than 3 kWh/day, replace it with the aboveTop freezer types are most efficientResist 2nd frig and separate freezer
If you have a 2nd refrigerator; measure it. If it uses more than 3 kWh/day, recycle it.
Turn off moisture control
Water Heating
Solar Water HeatingUse Integrated Collector storage system if no freeze dangerBetter performance from open loop active system
40 sqft collectorDC solar powered pump for simple operation
Tankless gas backup (~77% efficiency)Elevated so hot water migrates to tankless gasReduces auxiliary and scaling rates
Electric: Heat Pump Water Heater (Air Tap for retrofit); COPs of 2-3; nearly as good as solar systemBeware of hot water recirculation systems without occupancy controls
Major appliancesPrefer gas appliances (reduces source energy)
Gas range with true venting range hoodGas dryer (supplemented by clothesline)Gas auxiliary heating (min AFUE= 0.81)
If all electric, choose most efficient range, dryer and heat pumpExisting: Replace appliance with most efficient models at point of natural replacementHorizontal axis (front load) clothes washer
Cuts power by 30% for wash; reduces water useReduces dryer energy by 10-20%Run in afternoons with solar hot water
Energy Star DishwasherChoose highest efficiency model using Energy Guide labelShort insulated plumbing runs to water heaterRun in afternoon with solar hot water
Other AppliancesChoose LCD flat screen TV vs. plasma (40% reduction!)Design controllable circuitry to allow turning off all elements of home entertainment center other than DVRUse smart switch for entertainment centerProvide similar circuit to home office to allow dispatch of all computer and peripherals except CPU & wireless router (otherwise use Isole or equivalent)Induction cooking if electric; venting range hood
Photovoltaic System
At least 4 kW for modest sized homeWill produce about 16 kWh/day
5-6 kW for larger home or existing homeWill produce about 20 - 25 kWh/day
Evaluate annual load to avoid purchasing more PV than neededExercise care that there is not array shading by trees, or architectural features (chimneys etc.)Try to use true south orientation to maximize outputZero Electricity home must live within these budgetsProvide user display to assure proper functionWash array in early summer & late fall in dusty areas
Real Time Feedback
Use real-time electricity feedback for homePreferably have similar device to show real-time PV system outputMinimize home loads vs. PV system outputReminders & altering household behaviorMonitor performance as new appliances added, for cleaning array of dust etc.Collect utility records to obtain long-term performance
Successful Zero Net Energy Homes in the Southeast:
What’s New?
Danny Parker
Southface Institute, May 2012
Many new ZEH…• ORNL• NREL• Building America teams• Independent builders• This one in Wheatridge,
Colorado is true ZEH
New Vital Understanding of Cost Effectiveness for ZEH
• Cost effectiveness is different for ZEH home
• Defined by cost to produce one kWh/day
• Generally 1 kW of PV will produce about 4 kWh/day
• Cost: $6500/kWDC
• Cost 1 kWh/day= $1600• Efficiency measure is cost
effective that can reduce 1 kWh/day for less than $1600
Site shading for Renewable Features: Big Deal…
• Solar Water Heating• PV performance impact
Digitized Shading Evaluation
Cool Shingles• 25% reflectance• Plus color• GAF Timberline
Cool Series• $50-$100 more per
square
Poor Performance from GSHPs• Geothermal heat pump
performance• Two GSHP systems• Panama City: 1.5-ton
Closed loop system with 200’ vertical well
• Gainesville, 2-ton, open loop GSHP, 120 ft well
Closed loop GSHP: Specs• Florida Heat Pump
– GT018 - 1VTC
• 1.5 ton unit– Closed loop with
vertical injection well– ISO 13256 EER= 18.3
Btu/Wh, Capacity = 16,000 Btu/hr
– 1/6 hp Grundfos circulation pump (6.4 gpm)
Performance of Closed Loop GSHPPanama City ZEH Closed-loop 1.5-ton Geothermal Heat Pump
Performance: September 30th 2008
Hour of Day: September 30th 2008
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GSHP Total Power: 14.6 kWhLoop Circulation Pump: 2.2 kWhSupply air temp: 61.7 FInterior temp: 73.3 FReturn air temp: 73.4 F
dT
Panama City ZEH Closed-loop 1.5-ton Geothermal Heat PumpPerformance: September 30th 2008
(Tested air flow = 660 cfm)
Hour of Day: September 30th 2008
0 2 4 6 8 10 12 14 16 18 20 22 24
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105EER: 7.4 Btu/WhRuntime Fraction (0 - 1.0) Supply Temp: 61.7Interior Temp: 73.4 FReturn Temp: 74.3 FReturn fluid t: 89.2 FLeaving fluid t: 94.5 F
Air sidedT
EER =8.5 Btu/Wh @77 F return T
FluiddT
High Efficiency Motor Retrofit• Save 50% of blower
power• Converts to Variable
speed motor• Better humidity control
& more quiet
Newer, Bigger Televisions…• Now as many TVs as occupants
in average U.S. household• TVs on an average of 6 hrs/day• Owned for ten years• Growing electrical demand;
large HDTVs: 100 W to 600 W• Plasma is generally worse, but
lots of variation• Energy Star labels: Nov. 2008• FTC Energy Guide: 2011
Very High Efficiency Inverter Controlled Heat Pumps
New DC Ceiling Fan Motors
• New DC ceiling fan motors drop power use by 70%
• Several manufacturers:– Monte Carlo– Emerson
• Emerson Midway Eco is most efficient model– 24 Watts on high speed
Hot Water System Laboratory• Tankless gas systems save
approx. 22% measured vs. storage systems (COP = 0.73 vs. 0.57)
• Tankless electric saves 4% vs. standard storage tank
• Solar Water Heaters: (March 2009- Feb 2010); referenced to electric storage tank– ICS: 47% reduction in energy – Flat plate: differential control;
pumped: 78% reduction– Flat plate: PV pumped: 74%
reduction
Importance of Pipe Insulation• Non-solar systems: no
measureable change• Dramatic impact on solar systems
– Flat plate differential system: • COP increase to 5.54 to 8.30• Solar fraction to 84% to 89%
– PV pumped system: COP from 3.69 to 6.06
• Solar fraction to 76% to 85%– ICS system: COP from 1.86 to
2.12• Solar fraction to 51% to 58%
• ½” rubber closed cell foam insulation: R-2; recommend 1” insulation be used on solar circulation piping at a minimum
Typical Solar system: Flat PlateSurface area: 40 sqft
– Loss coefficient: 0.734 Btu/sqft-F
– Transmittance absorptance: 0.78
– Storage tank volume: 80 gallons
– Two tank system with natural gas
– Heat exchanger correction factor: 0.88
– 120 Watt pump
2 kW PV system….
More efficient washing machines &…
• Cold water detergents greatly reduce energy for washing clothes
• Most of washing machine energy is for heating water
• And for removing water leftover from the spin cycle for the energy-gobbling dryer
• Want a high EF
Need: Better clothes dryers• Clothes dryers: 4% of U.S.
energy• More electricity than modern
refrigerators: ~800 kWh a year• 45 therms a year for gas• Crude devices
– 3.01 lb of clothes/kWh– 53% efficiency is typical
• Large potential efficiency gains– Heat pump source– Heat exchanger– Improved controls
0 Energy 800 kWh
45 therms
Bosch: Heat Pump Clothes Dryer• EcoLogixx WTW86560AU
Cuts energy use in half for electric clothes dryer
• Uses heat pump & heat exchanger
EnergyGauge USA V. 2.8
• Version 2.8 is released…• Faster, more powerful• Improved rendering of building
geometry, heat pumps, cool roofing.
• Simulation of photovoltaic systems
• Solar water heating systems (active & batch)
• Hourly output of energy-end use, thermal and humidity data
• New TMY3 weather data
Evaluation of ZEH Designs• Same home in Tampa…• Add 2 kW PV array south• PV System #2 is identical, but
faces west• Which better?• West better matches load
shape, but building is far too inefficient for PV!
• Make it more efficient!
BEopt• NREL• Building Energy
Optimization• Hourly
simulationengine
• Research Tool• Evaluates all
options for new buildings
• Not available to general public
TED 5000 is awesome….• The Energy Detective (TED)• $350; installs in minutes• Instantaneous feedback• True kW, can show both
house and solar output• Send signals over house
wiring; also internet gateway• Current data; monthly cost• Data available on Google
Power Meter and TEDFootprints
• Google Power Meter in limbohttp://www.theenergydetective.com
Real-time Feedback & Monitoring
Ideas about what makes a differenceAC
Refrigerator
Google Power Meter GoodiesWeek
Month
PV Display Devices….• Sunny Beam for SMA
inverters• Wireless, auto
downloads data to PC• Displays total power
today so far• Current output• Last 30 days• Total Annual kWh
Measure your way to success…
Open Loop Water Source GSHP• Energy use only
15.4 kWh/day– Unoccupied
• Specs called for ½ hp pump; 1 hp pump was installed
• 180 FOH, 1/3 hp could work
• Note that pump power is 60% of total system power
• Compressor/fans is only 40%!
Gainesville ZEH Open-loop 2-ton Geothermal Heat PumpPerformance: August 15th 2008
Hour of Day: August 15th 2008
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GSHP Total Power: 15.4 kWhWell Pump: 9.3 kWhCompressor & Fan: 6.1 kWhSupply air temp: 59.2 FInterior temp: 75.2 FReturn air temp: 75.2 F
dT
A Research Institute of the University of Central Florida
Winter Infiltration Resultsfrom the FRTF Laboratory
Building America Stakeholders MeetingAustin, TX
March 1 2, 2012
Philip Fairey, Danny Parker
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Project Objectives
Under side by side, in situcontrolled conditions:
• Measure effectivenessof various energyretrofit improvements
• Produce high qualityempirical data setuseful for home energysimulation verification.
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
• Two identical side by side 1536 ft2, concreteblock, slab on grade residences
• Single pane fenestration, evenly distributed
• No concrete block wall insulation
• R 19 ceiling insulation (current code minimum)
• SEER 13 w/strip heat HVAC systems
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Lab Home Floor Plan
32’0”
48’ 0”
Interior wallsnot present incurrent testconfiguration
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Occupancy Gains
• Automated (computer controlled) heat andmoisture gains scheduled by time of day
• Based on RESNET lighting, appliance andmiscellaneous energy usage amendment
• Imposed using BA benchmark hourly scheduleswith slight modifications
• Includes lighting and appliance gains andoccupant gains– Sensible gains 15.5 kWh/day
– Latent gains 12.1 lb H2O/day
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Scheduled Internal Gains
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Enclosure Air Leakage Set Up
• Both home enclosures air tightened to achieve2.5 ach50
• Air distribution systems in both homes tightenedto achieve 20 cfm25 (Qn=0.013)
• Leaky home configured with 4 controllable ceilingleakage sites providing ~70% of leakage areaneeded to achieve ~9 ach50
• Remaining 30% of leakage area in leaky homeachieved using metal shims at all windows.
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Ceiling Infiltration Sites
Ceiling side port Attic side port
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Enclosure Leakage Test Results
Leakage Parameter: Leaky Home Tight Home
cfm50 1926 520
ach50 9.17 2.48
C 182.3 36.0
n 0.603 0.683
R sq 0.99805 0.99983
ELA (in2) 118.9 26.3
SLA 0.000538 0.000119
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
January Temperature Data
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Average Day During Tests
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
January Heating Data
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Average Day Heating Energy
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Heating Energy Characterization
Outliers due to buildingthermal capacitance
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
But . . . It’s Still the Humidity!
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
January Indoor RH Histogram
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Why Leaky is Dryer
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Estimated Infiltration Rates(Moisture storage and condensation not included)
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
General Findings• Moisture control is a critical issue
– More than 70% of hours exceeded 70% RH in tight home– Only 8% of hours exceeded 70% RH in leaky home– Significant condensation on single pane windows and glassdoors in tight home led to local mold growth during tests
• Mild weather resulted in humidity control issues inboth lab homes– Outdoor dewpoint temperatures sometimes to high foreffective indoor RH control in leaky home
– Tight construction exacerbates mild weather humidityissues
– Enthalpy controlled ventilation systems should beevaluated in light of humidity control results.
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Window Condensation
Condensation on all windowsof tight building
No condensation onwindows of leaky building
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Window Condensation
Much less condensation on screened portion
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Window Condensation
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Tight Home Glass Door Conditions
Water on floor fromdoor condensation
Mold on drywall atbottom of door
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Tight Home WindowMold
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Some Caveats
• Lab homes have little moisture capacitance– No interior walls
– No carpeting and no furnishings
• Lab homes operation is atypical– No exterior door openings
– No kitchen or bathroom ventilation fan operation
• Could internal moisture generation schedulebe the largest source of humidity controlproblem?
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Immediate Follow up Tests
• Immediately following the January test period– Lab homes were dried out by eliminating internalmoisture generation and air conditioning as much aspossible
– Internal moisture generation was cut in half from12.10 lb/day to 6.05 lb/day
• On February 8th, the heating systems in both labhomes were reactivated
• Cold snap on February 11 14 allowed additionalmeasurements under the revised internalmoisture generation schedule.
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
February Drybulb Temperatures
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
February Heating Energy
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
February Indoor Relative Humidities
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
February Indoor RH Histogram
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
February Dewpoint Temperatures
Leaky home tracksoutdoor dewpointduring this period
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Re Test Implications
• Halving internal moisture generation results insignificant difference in percentage of hoursexceeding 70% RH
• Indoor RH during cold period is 25% greater intight home compared with leaky home
• On February 14th indoor dewpoint in leaky homeis virtually identical to outdoor dewpoint
• Additional outdoor ventilation air is needed tobetter control indoor humidity in tight homes.
A Research Institute of the University of Central Florida
Questions?
A Research Institute of the University of Central Florida
Extra Slides
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Just Before the Cold Snap!
FLORIDA SOLAR ENERGY CENTER — A Research Institute of the University of Central Florida
Null Tests – No HVAC
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