danny parker sf lecture presentation

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 …

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Real-time Feedback & Monitoring

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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

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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


--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 -


Summer Operation: Power


----Condenser----Air Handler----Mini-split

LW

Slide 23

LW17 I inserted text box to make color key biggerlwigington, 10/23/2011


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

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

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

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


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

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

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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.


• 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


Lab Home Floor Plan

32’0”

48’ 0”

Interior wallsnot present incurrent testconfiguration


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


Scheduled Internal Gains


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.


Ceiling Infiltration Sites

Ceiling side port Attic side port


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


January Temperature Data


Average Day During Tests


January Heating Data


Average Day Heating Energy


Heating Energy Characterization

Outliers due to buildingthermal capacitance


But . . . It’s Still the Humidity!


January Indoor RH Histogram


Why Leaky is Dryer


Estimated Infiltration Rates(Moisture storage and condensation not included)


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.


Window Condensation

Condensation on all windowsof tight building

No condensation onwindows of leaky building


Window Condensation

Much less condensation on screened portion


Window Condensation


Tight Home Glass Door Conditions

Water on floor fromdoor condensation

Mold on drywall atbottom of door


Tight Home WindowMold


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?


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.


February Drybulb Temperatures


February Heating Energy


February Indoor Relative Humidities


February Indoor RH Histogram


February Dewpoint Temperatures

Leaky home tracksoutdoor dewpointduring this period


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.


Questions?


Extra Slides


Just Before the Cold Snap!


Null Tests – No HVAC

danny parker sf lecture presentation

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