Natural Ventilation. Course PTP6055 AIA Provider J877 9/18/2013

Transcription

1 Natural Ventilation Course PTP6055 AIA Provider J877 Price Industries is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non- AIA members are available upon request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA or any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation 1

2 COPYRIGHT MATERIALS This presentation is protected by US and International copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. Price Industries, Inc., Learning Objectives At the end of this presentation, you should understand: How can natural ventilation be applied to a variety of building designs Can a naturally ventilated environment be comfortable What are the ventilation strategies associated with natural ventilation What is a hybrid natural ventilation system 2

3 Introduction to Breathing Buildings Price & Breathing Buildings - History BP fund research project through Cambridge & MIT focused on low energy buildings Unique low energy ventilation system developed. Patent filed in UK First building with NV technology completed Engaged as ventilation & energy consultants for over 50 high-profile clients and projects NV installed in over 90 buildings spanning education, performance, retail and commercial ASDA adopts BB NV strategy and technology in Retail Stores BB project receives UK s first and only BREEAM outstanding healthcare building award BB partnership with Price Industries to access North American markets Why Naturally Ventilate? Potential energy savings Potential lower costs (capital, maintenance, energy) Occupant connection with outside Many more 3

4 Electricity End Uses in Large Office Buildings in California Source: CEUS, 2002, n = 249 Why not Naturally Ventilate? [Potential] Barriers occupant comfort concerns design team confidence cost codes / local authorities acoustics / sound fire / life safety adjacency / security controls potential energy increase? air quality / OSHA Standards integration with HVAC systems architecture control of internal loads climate control of solar loads product availability availability of design tools and guidance lack of occupant education / when to open etc 4

5 Supplied Ventilation Rate (CFM) 9/18/2013 Natural Ventilation Location Suitability Climate will have an impact on operable hours throughout the year F is the ideal exterior temperature range Natural Ventilation LEED Opportunity for Ventilation Rates Guaranteed Flow Rate Occupied Hours for Year 30% increase from 62.1 ASHRAE ventilation rate

6 Perceived Temp (F) 9/18/2013 Natural Ventilation ASHRAE Adaptive Comfort 90 Adaptive Comfort Assessment for Year for Open Offices 85 Upper 80% Acceptability Limit Lower 80% Acceptability Limit Weighted Mean Outdoor Temp (F) Natural Ventilation Design Considerations Indoor Air Quality Floor/wall space Thermal mass Building construction material Glazing area Climate Occupancy profile 6

7 North American Installs Ventilation Strategies Single sided Windows Cross-ventilation Wind driven Mixing ventilation Exchange flow Displacement ventilation Buoyancy driven 7

8 Height 9/18/2013 Buoyancy Driven Ventilation Hot air driven out at top Interior air Exterior air Cold air driven in at base Pressure Courtesy: CPP Wind Engineering Consultants Wind Driven / Cross Flow Ventilation Courtesy: CPP Wind Engineering Consultants 8

9 Height Height Buoyancy head 9/18/2013 Displacement Through Open Window Hot air driven out at top Neutral point no flow in absence of wind Interior air Cold air driven in at base Pressure Exterior air Inside (warm) Outside (cold) Open window Limited penetration depth and buoyancy head Displacement Through Stacks Hot air driven out at top Neutral point no flow (in absence of wind) Interior air Exterior air Cold air driven in at base Pressure 9

10 Height 9/18/2013 Displacement Through Stacks Hot air driven out at top Inflow Interior air Exterior air Cold air driven in at base Pressure Natural Ventilation Opportunity (ºC) 10

11 Natural Ventilation Opportunity Options NV Year round or Hybrid Heating + NV if limited number of hours Mechanical ventilation with heat recovery if significant portion of the year spent here Low-energy fan assistance to eliminate cold draughts using internal gains Low-energy fan assistance to eliminate cold draughts using internal gains Optimal NV temperature range NATURAL VENTILATION HYBRID Optimal NV temperature range Nightcooling or comfort cooling can be interlinked; NV at minimum rate, based on CO 2 Radiant cooling and mechanical ventilation at minimum rate, based on CO 2 External Temperature: 32º F 60º F 76º F 11

12 Previous Cold Weather Strategies Traditional approach is to pre-heat the incoming air. Heat balance for occupied buildings shows building already has sufficient heat to maintain desired temp (until T ext < ~7 C (45 F) Complaints when air introduced to occupants below ~ 16 C (~60 F) Cold Weather Strategies Heat Source Occupants Lighting IT Solar Fabric loss TOTAL Gain 32 x 65 = 2 kw 70 x 15 = 1 kw 0.5 kw 0.5 kw -1 kw 3 kw Q = ρ. C p. V. T => T = 59degF Cold Air Needs Preheating to 60 o F T classroom = Internal gains + Preheat= 88 o F Overheat in winter > Increase ventilation rate > Increased preheating > Increase Energy Usage! 12

13 Previous Cold Weather Strategies With conventional strategies, energy is wasted in preheating the incoming air, and preheating higher volumes of fresh air than are necessary to maintain Indoor Air Quality. Energy Consumption of a typical classroom in a similar climate to Portland, Oregon Heating Fans Conventional Natural Ventilation MVHR with bypass all year Winter MVHR with summertime natural ventilation and fan boost e-stack Mixing ventilation ventilation Natural Ventilation PRODUCTS & APPLICATIONS 13

14 Fundamentals of NV Technology Challenges Draft in cool seasons proximity to openings Stale air in cold seasons openings closed Increased CO 2 levels Secure night cooling Compounding preheat energy Fundamentals of NV Technology Air flow Strategies Winter mixing mode allows for an increase in hours when NV is appropriate 14

15 Annual Hours Annual Hours 9/18/2013 Fundamentals of NV Technology Air flow Strategies 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 30% 29% San Francisco Heating Natural Ventilation 20% 62% 60% Portland Seattle LAX Burbank Fundamentals of NV Technology Air flow Strategies 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Heating Additional Free Hours Natural Ventilation 30% 29% 55% San Francisco 31% 20% 37% 62% 60% 35% 31% Portland Seattle LAX Burbank 15

16 Fundamentals of NV Technology Air flow Strategies San Francisco Portland Seattle Winter Mode (hrs / yr) Mid Season Mode (hrs / yr) Summer Mode (hrs / yr) NV Products Overview Rooftop Units Fan assisted Dampened openings Facade High level Low level Atrium Interior air exchangers Winter Mode Summer Mode 16

17 NV Products Roof Stack Unit with Divided Mixing Box Low power mixing box Flow divider Insulated low leakage damper with spring return actuator Penthouse Louver Flow Divider Low Leakage Damper Mixing Box NV Products Roof Stack Unit Low power mixing fans extend hours of operation Flow divider for exhaust Low leakage damper Cylindrical Flow Divider Insulated Shaft Opposed Modulating Damper Penthouse Louver Roof Curb Low Energy Mixing Fans 17

18 NV Products Facade Mounted Facade Mounted Roof Access Not Required Combined with operable opening Low power mixing fans Winter Mixing Mode Summer Exhaust Boost NV Products Facade Mixing Unit High Level Low power mixing fans Draft prevention in winter mode CO2 and temperature sensors 18

19 Fundamentals of NV Technology Atrium Strategy Air transfer via attenuators Low power fans - Summer Boost Room-to-Atrium - Winter Mixing - One unit air in - One unit air out Combined with high level openings in atrium Atrium as mixing chamber in winter NV Products Atrium Unit Low power mixing fans Draft prevention in winter mode CO2 and temperature sensors Remotely mounted central control panel Control signals for automated high/low level openings Optional integrated sound attenuation Grille and Fire Damper Low Energy Fan Egg crate Grille 19

20 NV Products Insulated Damper Unit Insulated low leakage damper Heavy duty grille construction Central control panel mounted remotely NO MIXING FAN NV Products Facade Unit Low Level Insulated low leakage damper Heavy duty grille construction Central control panel mounted remotely Optional sound attenuation 2 Drainable Louver Grille Modulating Damper Insulated Sleeve Sound Attenuator 20

21 Monkseaton High School The quality of air, and the improvement in the environment in a building with exceptional air and light quality has set new standards. - Paul Kelley, Monkseaton Principal Monkseaton High School Students, staff, and visitors all comment on the refreshing change from the institutional air they have always experienced in public buildings. - Paul Kelley, Monkseaton Principal 21

22 Natural Ventilation CASE STUDIES Case Studies Thomas Clarkson Academy ASDA Langley Mill, UK 36,000 ft 2 Supermarket Opened November

23 TCA Case Study The System TCA Case Study The System NV Deployed Throughout Stack units in common spaces Attenuator units in lower classrooms Stack Roof units in upper classrooms 23

24 TCA Case Study The System TCA Case Study The System 24

25 ASDA Langley Mill ASDA Case Study The System 12 Stack units w/ integrated control Relief in summer mode Integral fans provide boost mode Inlet in winter mode Gas heater provides additional heat, when required Exhaust through bakery, etc. 25

26 Temperature 9/18/2013 ASDA Case Study The System ASDA Case Study Results Exterior Average High-level Low-level Average Average CO /07/ :00 24/07/ :00 25/07/ :00 26/07/ :00 27/07/ :00 26

27 Energy HVAC and Refrigeration Savings 56,067 kwhr saving 46,452 kwhr saving Energy Total Energy Consumption Total energy load with NV is lower than other stores 12% lower than MV Store 1, saving 54k ($85k) and 338 tons CO 2 /yr 17% lower than MV Store 2, saving 62k ($97.5k) and 384 tons CO 2 /yr 27

28 Perceived Temp (F) 9/18/2013 Warm Weather Strategies Discussion on Thermal Comfort HYBRID SYSTEM Remodel from Overhead mixing to NV Building is located in Northern California Large Open Plan Office Penthouse Louver Flow Divider Low Leakage Damper Chilled Sail Mixing Box Warm Weather Strategies Roof Stack Unit - Only 90 Adaptive Comfort Assessment for Year Upper 80% Acceptability Limit Lower 80% Acceptability Limit Weighted Mean Outdoor Temp (F) 28

29 Perceived Temp (F) Temperature (F) 9/18/2013 Warm Weather Strategies Hybrid Solutions - Radiant Cooling & RS Unit 90 Adaptive Comfort Assessment for Year for Open Offices Upper 80% Acceptability Limit Lower 80% Acceptability Limit Weighted Mean Outdoor Temp (F) Warm Weather Strategies Hybrid Solutions- Radiant Cooling & RS Unit 70 Chilled Water Setpoint Compared with Dew Point DewPoint (F) CHWST Hours Chilled water set point = Dewpoint + Safety Factor (2 F) 29

30 Power (Btu/h) Robustness Efficiency 9/18/2013 Warm Weather Strategies Hybrid Solutions- Radiant Cooling & RS Unit Chilled Sail Cooling Capacity Warmest hours Hours Summary Single-sided simple opening windows (low occupancy) Low level and high level windows / louvres (utilises buoyancy head) Cross-flow, roof-mounted units (deeper plan spaces) Control strategy to regulate internal conditions, responds to internal / external temperatures and indoor air quality, night cooling Low energy fan assist (initiate flow, improve thermal comfort) Aims: Thermal comfort Indoor Air Quality Low Energy 30

31 Questions? 31