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Brooklyn Cohousing, BBBD Slide 1
Brooklyn Cohousing Energy DesignDavid White, Right Environments
www.rightenvironments.comcollab. Marc Rosenbaumwww.energysmiths.com
Brooklyn Cohousing, BBBD Slide 2
Comparison of Heating Energy Demand
99
52
31
1550
10
20
30
40
50
60
70
80
90
100
New York Average* Solaire** New EnglandAverage***
228 East 3rd Passivhaus
Dem
and
(kbt
u/sf
yr)
All figures except Passive House assume 85% heating plant efficiency*From "Fuel Use in Multifamily Buildings;" HE Nov/Dec 1999, p 30.**Design prediction. Measured usage of natural gas from 2004-2007 (including absorption chiller) was 13% higher than predicted on average.***From EIA CBECS data set
Brooklyn Cohousing, BBBD Slide 3
Existing Wall R-24 (with 3” spray foam at mnfr claim R-6.9/inch)New Wall R-35New Roof R-60Slab R-26 (4” polyiso)Windows R-5 to R-6Curtain Wall R-4.2 (Kawneer 7550 Wall, LOF EA2 #3 #5, Argon)Heat Recovery 75%
Comparison of Climates
4875
5490
7665
341
453426
0
1000
2000
3000
4000
5000
6000
7000
8000
Stuttgart New York City Burlington
Win
tero
city
(HD
D65
)
0
100
200
300
400
500
600
700
800
Sola
r Rad
iatio
n (k
Btu
/sfy
r)
HDD65kBtu/sfyr
PH Performance Criteria
Brooklyn Cohousing, BBBD Slide 4
“Interior Insulation Retrofits of Load-Bearing Masonry Walls in Cold Climates” 2007-03-28 by John Straube and Chris Schumacher, Building Science Corporation, p11
Interior Insulation
Brooklyn Cohousing, BBBD Slide 5
spray foam issues – GWP, permeability, air tightness at details, using manufacturer’s
claimed R value for energy modeling (more conservative for peak load)
installation qualitySPF Issues
Brooklyn Cohousing, BBBD Slide 6
Harvey, “Net climatic impact of solid foam insulation produced with halocarbon and non-halocarbon
blowing agents,”Building and Environment 42, 2007.
SPF Issues
Brooklyn Cohousing, BBBD Slide 7
multizone PHPP method. allows development of peak loads for each apartment. common design attributes are easily changed.
Multi-Zone PHPP
Brooklyn Cohousing, BBBD Slide 8
ASHRAE 62.2 19 cfm supply NYC 2008 45 cfm exhaust Target ~25 cfm (.42 ach by PH calcs)-> transfer duct from kitchen to bathroom
Outdoor Air Flowrates
Brooklyn Cohousing, BBBD Slide 9
0°F ERV 65°F
125°F
Hot Water Duct Heater (From Gas Boiler)
Branch to Apartments
Winter
60 cfm / 1000 sf * (125-70) F * 1.08 = 3.6 btu/hrsf
Winter
Classic PH Heating System…
Brooklyn Cohousing, BBBD Slide 10
60 cfm / 1000 sf * (77 – 40) F * 1.08= 2.4 Btu/hrsf = 5,000 sf/ton
95°F ERV/DX Unit 40°F
40-70°F
Hot Water Duct Heater (From Solar)
Branch to Apartments
SummerSummer
…not selected
Brooklyn Cohousing, BBBD Slide 11
AHU
Ducted split unit
Brooklyn Cohousing, BBBD Slide 12Wall mounted split unit
Brooklyn Cohousing, BBBD Slide 13
Ducted split
From ERV
From ERV
Return
Return
backdraft damper
Backdraft damper
To rooms
To roomsDucted split
Outdoor air ducting
Brooklyn Cohousing, BBBD Slide 14
mechanical
ability to move heat from one side of building to the other with VRV systemalso important in terms of meeting building peak load…
mechanical sizing of VRV system for bldg peak load, not installed indoor unit capacity.
mechanical collective billing
Brooklyn Cohousing, BBBD Slide 15
Central ERV’s
+ Collectively managed, minimal maintenance with no need to enter apartments+ Lower cost?+ Minimal envelope penetrations- No user control - No response to cooking, bathroom use, occupant absence- May have very high fan power requirement
Alternative: decentralized H/ERV’s connected to shared supply/exhaust shafts
Centralized outdoor air
Brooklyn Cohousing, BBBD Slide 16
mechanical
solar fraction, panel size, etc. can meet PH without solar DHW, but americansuse a lot so in reality it matters a lot – about 4x the demand for heating!
Illustration: Tom Lane, “Solar Hot Water Systems; Lessons Learned 1977 to Today.”
Solar hot water system
Brooklyn Cohousing, BBBD Slide 17
Conclusions• PH is achievable in NYC – easily for new construction, more difficult with retrofit• Mass wall interior retrofit is very difficult and highly sensitive to climate• Important to be on the ball early: team coordination, costing, integrated efforts• PH sells itself: cost, IEQ, passive survivability, fuel security, quality assured performance, sustainability