brooklyn cohousing energy design david white, right ... · brooklyn cohousing, bbbd slide 3...

Brooklyn Cohousing, BBBD Slide 1

Brooklyn Cohousing Energy DesignDavid White, Right Environments

www.rightenvironments.comcollab. Marc Rosenbaumwww.energysmiths.com


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


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


“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


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


Harvey, “Net climatic impact of solid foam insulation produced with halocarbon and non-halocarbon

blowing agents,”Building and Environment 42, 2007.

SPF Issues


multizone PHPP method. allows development of peak loads for each apartment. common design attributes are easily changed.

Multi-Zone PHPP


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


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…


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


AHU

Ducted split unit

Brooklyn Cohousing, BBBD Slide 12Wall mounted split unit


Ducted split

From ERV

From ERV

Return

Return

backdraft damper

Backdraft damper

To rooms

To roomsDucted split

Outdoor air ducting


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


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


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


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

brooklyn cohousing energy design david white, right ... · brooklyn cohousing, bbbd slide 3...

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