Big Buildings: Lessons from NY and Vancouver

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© Steven W

inter Associates, Inc. 2017

Big Buildings: Lessons from NY and Vancouver

© Steven

Winter Associates, Inc. 2017


© Steven W


New York High Rise PH Projects

Cornell Tech Tower: 26 Stories, 352 Units


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211 W 29th: 25 Stories, 55 Units


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511 E 86th Street: 27 Stories, 139 units


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425 Grand Concourse: 28 Stories, 277+ Units


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Sendero Verde: 3 Buildings33 Story Tower, 600 units total


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Boston High Rise Project

Winthrop Square55 Story Tower17 Stories Office - PH33 Stories ResRetail at Base

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VENTILATION (WITH MONTE)Big Buildings – Lessons from New York and Vancouver


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Central vs. Local ERV’s1 2

Individual ERV Central ERV

Penetrations

Façade‐ 2 penetrations/apartment

‐ separation exhaust/supply 10' NYC Mech Code‐ exhaust 2' from apt window, 4' neighbor

Rooftop only

Metering Resident Meter (ERV) Owner Meter (ERV)

Pros ‐ Arch ‐ No slab penetrations ‐ No horizontal ducts

Cons‐ Arch‐ 10' façade separation‐ Ceiling height issues‐ Ductwork, Aesthetics

‐ Floor space reduction‐ Large slab penetrations

‐ Rated shafts

Pros‐ MEP‐ Continuous, boost flow achievable

‐ PH certified units available‐ Continuous, boost flow achievable

Cons ‐ MEP‐ Variable flow rates achievable, complexity of controls‐ Rooftop ERV compliance with PH testing would be

beneficial, currently unknown

PH Compliance/Testing Precedent for unitized ERV to provide flow rates No precedent for central balanced system w/ HR in US

Operations‐ In‐unit maintenance, ‐ Filter change 3x/yr

‐ Rooftop maintenance

First Cost similar


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HRV’s & ERV’s

120 Watts

220 Watts


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Whole-House Ventilation


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Implications of Unitized vsCentral


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Static Pressure and Fan Power


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ERV Testing & Balancing

• Image from Eco-Village• Riser diagram for Cornell• Static pressure issues and fan power


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Central ERV’s

• If central in multi-family, – recommend constant volume to reduce

complexity of controls– Must balance code and PH requirements– Special consideration from both parties

may be necessary


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Central Exhaust SystemsRoof Fans

• Vertical shaft• Horizontal take-offs• Sidewall or ceiling

grilles at each floor

All or Nothing• Continuous

Venting• Intermittent


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Delivery System Leakage Implications of exhaust system leakage not as well understood by contractors

Leakage at sheetrock

connections Leakage at shaft/sheet metal connections


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What actually happens…

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

9

8

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r of B

uild

ing

Exhaust CFM at Each Floor of a 9-story Building

BathroomVentilationKitchenVentilation30 CFM = SWA Recommended

Ventilation Rate

Over-ventilation (energy waste)

Under-ventilation (Potential indoor air quality problems)

Balancing and IAQ

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Ducts Engineered/Installed for Precise Flow


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0 10 20 30 40 50 60 70 80 90 100

9

8

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Floo

r of B

uild

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Exhaust CFM by Floor: Before and After Retrofit

F-line Kitchen Pre-retrofitF-line Kitchen Post-retrofit

35 CFM = SWA Recommended Ventilation

pre-retrofit: register closed


pre-retrofit: register clogged


Note: Post Retrofit measurements were only made on ODD floors.

Reduce System Leakage

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DOMESTIC HOT WATER AND DISTRIBUTION

Big Buildings – Lessons from New York and Vancouver


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DHW Percent of Whole Building Energy Demand (site)

Cooling and Dehumidifcatio

n14%

Heating12%

Lighting and Appliances

37%

DHW37%


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DHW Generation

Cooling and Dehumidifcation

14%

Heating12%

Lighting and Appliances

37%DHW ‐ Generation

27%

DHW ‐Distribution and

Losses10%

DHW37%


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Multi-Family DHW OptionsEnergy Type DHW Option Pros Cons

Fossil FuelsCondensing Boiler

Conventional technology Fossil fuel use

CHP“Free” hot water heating Typically only sized

for 70% of demand

All Electric

ResistanceLow upfront cost; readily available

Very inefficient

Tankless ResistanceModest upfront cost; no standby losses; compact

Very inefficient

Solar ThermalLow operating cost Not enough roof

space in MF buildings

Unitized Heat Pump Water Heaters

Very efficient Very difficult to fit in units; Cools space

Split Heat Pump Waters Heaters

Very efficient Not readily available options in U.S.


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Unitized Heat Pump Water Heaters


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HPWHs inApartments


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Other Options• Mayekawa Commercial

A/W HP– Can operate down to 14F– Back-up will be needed in

cold climates– Potential to use ERV exhaust

air to improve efficiency– Large: not good for buildings

w/ fewer than 100 units


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New ProductsSanden Outdoor packaged HPWH

•CO2 refrigerant•Extremely high pressure systems

•Water is pumped out to unit – freeze protection necessary


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Future Options• Split HPWHs available in Europe &

Asia• Condenser outside• Soon in US…?

WH


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DHW and PER

• Gas boilers hurt PER • Not enough roof space for sufficient

solar


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Central Gas DHW


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Central HP Electric DHW


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DHW Distribution (Site)

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DHW – Recirculation• Typical design in

large MF buildings– recirculation for MF– Individual Pipe runs

from recirc. lines to taps < 20 ft.

• Design– One vertical riser per

plumbing cluster

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Inefficient DHW Recirculation©

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Efficient DHW Recirculation©

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Recirc. Pipe Length

Pipe Heat Loss

Internal Heat Gains

Cooling Demand

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Efficient DHW Design• Reduce # of risers

– Cluster plumbing locations when feasible

• Insulation– Code minimums

• Reduce diameter of pips

• Reduce branch lengths

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DHW - Recirculation©

StevenW

inter Associates, Inc. 2017Source: SWA PH Modeled Data

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Recirculation and PE Demand

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Pipe Diameter and Pipe Insulation Effect


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Non-storage DWHR systems• Non-storage systems usually have a copper

heat exchanger that replaces a vertical section of a main waste drain.

T =104°F

T =95°F

T =50°F

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DWHR on SWA PH Projects1. Project 1 (Hybrid version) / 68 units, 4 floor, TFA =71070 ft2 / DSS model T‐DW3 (55% efficiency)

Without drain recovery With drain recovery % improvementPE/PER (KBTU/ft2∙yr) 46.39 44.01 1.6

DHW generation PE/PER value (KBTU/ft2∙yr)

16.5 14.1 10

1. Project 2/ 144 units, 22 floors, TFA = 96046 / DSS model T‐DW3 (55% efficiency)PE/PER (KBTU/ft2∙yr) 37.54 35.95 2.9


16.5 14 14.3

1. Project 3/ 305 units, 12 floors, TFA = 85070 / DSS model T‐DW3 (55% efficiency)PE/PER (KBTU/ft2∙yr) 36.74 35.16 3.6


15.4 12.9 11.7

DSS model T‐DW3 (55% efficiency)

Mean improvement (KBTU/ft2∙yr)

Mean % improvement

PE/PER 1.85 2.5DHW generation PE/PER value 2.5 12


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Modeling IssuesDHW Drain Waste

PHPP

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OVERHEATING, COOLING, AND ELECTRICAL LOADS

Big Buildings – Lessons from New York and Vancouver

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Heat Gains – Typical PH –COMBINE w/ next

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Solar Heat Gains

Internal Heat Gains

Single family• Shorter cooling season• Longer heating season• Window SHGC between

0.35 - 0.55

MF & Commercial• Longer cooling season• Shorter heating season• Relatively lower window

SHGC required

~30%

~70%

Solar Heat Gains

Internal Heat Gains

~30%

~70%

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Internal Gains• More internal gains/ft2 –

people, appliances– Magnified over larger

building area• ↑ Primary energy demand• ↑ Cooling energy demand • ↓ Heating energy demand

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Internal Gains - Multi-family

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Internal Gains - Multi-family• Corridor lighting

– Long, thin layout and jogs can yield high LPD

– Generally on 24/7• Common areas

– Laundry rooms– Fitness rooms– Mail & package rooms– Lobby– Additional loads

• Elevators– Very little actual data

• DHW– 24 hr. recirculation

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MF vs. SF – Modeling Data©

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Modeling Case Study Building Source: SWA PH Modeled Data

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MF vs. SF – Modeling Data©

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Modeling Case Study Building Source: SWA PH Modeled Data

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Core Design Differences• Multifamily (Building A)

– Occupancy 700+ people– Location NYC– Exterior walls R-20– Foundation walls R-10– Roof R-30– Double Pane Window

• U-0.25 Btu/hr.ft2.F • SHGC-0.27

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• Single Family (Building E)– Occupancy 3-4 people– Location Ithaca– Exterior walls R-50– Foundation walls R-20

(typically)– Roof R-90– Triple Pane Window

• U-0.16 Btu/hr.ft2.F• SHGC-0.60

Modeling: Internal GainsPHPP

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Energy Use Breakdown


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IHG Breakdown 23 Story MFTFA:# of Apts:# of Occupants:


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Effect of CA lighting on PE


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Cooling Example


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Cooling Example

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CASE STUDIESBig Buildings – Lessons from New York and Vancouver

Big Buildings: Lessons from NY and Vancouver

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