2020‐08‐19
1
Large Passive House Building HVAC The New England Experience
Mike Woolsey, Certified Passive House Designer Member iPHA, ASHRAE Voting Member ASHRAE SPC 227P Passive Building Business Development Manager Swegon
[email protected] +1 612 685 6519
Course credit: 1.0 PDH; 1.0 PHI CEU
2 Integrating HVAC into Large Passive House Building Design
2
1 2020‐08‐19
Learning Objectives
1. Understand the benefits of energy recovery ventilators in general, with special focus on their benefits to the Passive House project. 2. Understand the properties of energy recovery ventilators that are most valuable on Passive House projects. 3. Understand the limits of energy recovery ventilators when applied on Passive House projects. 4. Understand the integration of energy recovery ventilators in the Passive House design, with case studies.
3 Integrating HVAC into Large Passive House Building Design
3
Passive House Characteristics
4
2 2020‐08‐19
DRAMATIC ENERGY SAVINGS
Approx90% Up to75% reduction in heating & cooling reduction in total energy usage.
Introduction to Passive House www.naphnetwork.org
5
FROM EXPERIMENT TO POLICY
1st Modern Passive House: 1990
Introduction to Passive House www.naphnetwork.org
6
3 2020‐08‐19
BOLD IMPLEMENTATION
BRUSSELS, 2015: All buildings, private, public, new and retrofitted mandated Passive House performance.
EUROPE, 2020: Nearly zero-energy buildings.
Introduction to Passive House www.naphnetwork.org
7
COMPLEX BUILDINGS IN VARIED CLIMATES
Introduction to Passive House www.naphnetwork.org
8
4 2020‐08‐19
PASSIVE HOUSE CHARACTERISTICS
Airtight High Performance Openings Climate‐specific Insulation
Continuous Ventilation With Heat Recovery
No Thermal Bridges
9 Integrating HVAC into Large Passive House Building Design
9
PHI PERFORMANCE REQUIREMENTS Design Criteria – energy saving features
Criteria Alternate Criteria AIRTIGHTNESS
Infiltration / Exfiltration n50 (n0.2) ACH ≤ 0.6
HEATING
Annual Heating Demand kBtu/ft2•yr ≤ 4.75
Peak Heat Load Btu/ft2•hr ≤ 3.17
COOLING ≤ 4.75 Cooling kBtu/ft2•yr + climate specific dehumidification allowance
Cooling Load Btu/ft2•hr
THERMAL BRIDGING
Ψ Btu/(hr•ft•˚F) <0.006
10 Integrating HVAC into Large Passive House Building Design
10
5 2020‐08‐19
PHI PERFORMANCE REQUIREMENTS Design Goals – comfort and energy consumption
Criteria COMFORT
Indoor Temperature °F < 75 most of the year (90%)
Energy Demand Goals
Renewable Primary Energy Demand (PER) kWh/ft2•yr 5.6
RESULTS: Actual energy performance 40-80% less EUI than average new build.*
Sources: • Frappé-Sénéclauze,Tom-Pierre et. al. Accelerating Market Transformation for High-Performance Building • iPHA Fact Sheet 2019-02. Heating Energy Consumption: expectations confirmed in practice, International Passive House Association, https://news.passiv.net/archive/DGvow‐aeM/_mcmHyFPT/pKN8V60HUJ
11 Integrating HVAC into Large Passive House Building Design
11
12 Integrating HVAC into Large Passive House Building Design
12
6 2020‐08‐19
Question 1
• Name 2 of 5 Passive Building characteristics
13
13
Passive House HVAC
14
7 2020‐08‐19
AIRTIGHT CONSTRUCTION Saves Energy and Requires Continuous Ventilation
Airtight layer • saves energy by reducing infiltration of unconditioned air, and reducing exfiltration of conditioned air • improves comfort by reducing draftiness and keeping fine airborne particles outside • traps moisture and contaminants by preventing exfiltration Continuous ventilation • Replaces moist and contaminated air with conditioned outside air
Photo courtesy of Rockwool
15 Integrating HVAC into Large Passive House Building Design
15
AIRTIGHT CONSTRUCTION Energy savings example
700,000 Example 600,000 Building dimensions 100ft x 50ft x 50ft ASHRAE 90.1 3 500,000 Energy Standard Occupied volume 230,000ft (Btuh) for Buildings Envelope area 25,000ft2 loss
400,000 (2016) International Temperature, indoors 68°F heat 300,000 Energy Temperature, outdoors 10°F Conservation 200,000 Code (2016) Resulting 100,000 Passive House 0 0 2000 4000 6000 8000 10000 12000 Allowable envelope leakage (CFM)
Maximum tested Resulting infiltration Heating required due envelope leakage / exfiltration (CFM) to leakage (Btuh) Passive House 0.6 ACH 2,300 144,072 baseline IECC 0.25 CFM/ft2 6,250 391,500 +171% ASHRAE 90.1 0.4 CFM/ft2 10,000 626,400 +334%
16
8 2020‐08‐19
CLIMATE-SPECIFIC INSULATION Saves energy and maximizes benefits of energy recovery
Climate‐specific insulation • Saves energy by reducing heat flows into/out of the building • Improves comfort by keeping surface temperatures warmer in winter, cooler in summer • Reduces heating/cooling equipment size • Improves resiliance
Energy Recovery Ventilation • Saves energy by capturing heat, returning heat to building, rejecting heat in summer • Minimizes need for additional Photo courtesy of Rockwool heating and cooling • Reduces need for and size of 17 Integrating HVAC into Large Passive House Building Design central and terminal heating
17
Energy Recovery Air Handlers
18
9 2020‐08‐19
ENERGY RECOVERY AIR HANDLER Rotary Wheel Type HRV
EXHAUST AIR RETURN AIR
OUTDOOR AIR SUPPLY AIR
19 Integrating HVAC into Large Passive House Building Design
19
HEAT RECOVERY VENTILATOR (HRV) ROTARY WHEEL
20 Integrating HVAC into Large Passive House Building Design
20
10 2020‐08‐19
HEAT RECOVERY VENTILATOR (HRV) Plate type - Large
OUTDOOR AIR RETURN AIR
EXHAUST AIR SUPPLY AIR
21 Integrating HVAC into Large Passive House Building Design
21
ENERGY RECOVERY VENTILATOR (ERV) Winter Operation
• Continuous ventilation • Recovers sensible heat Exhaust Air Fan • Recovers latent heat Rotary Heat Exchanger 85% Sensible, 83% latent
Return Air Filter, MERV 13
13°F Exhaust Air (EA) Return Air (RA) 70°F 92% RH 30% RH
3°F Outside Air (OA) Supply Air (SA) 60°F 79% RH 36% RH
Outside Air Filter, MERV 13 Supply Air Fan
Outside Inside
22 Integrating HVAC into Large Passive House Building Design
22
11 2020‐08‐19
ENERGY RECOVERY VENTILATOR (ERV) Summer Operation
• Continuous ventilation • Recovers sensible heat Exhaust Air Fan • Recovers latent heat Rotary Heat Exchanger 85% Sensible, 79% latent
Return Air Filter, MERV 13
88°F Exhaust Air (EA) Return Air (RA) 75°F 41% RH 52% RH
90°F Outside Air (OA) Supply Air (SA) 77°F 39% RH 50% RH
Outside Air Filter, MERV 13 Supply Air Fan
Outside Inside
23 Integrating HVAC into Large Passive House Building Design
23
PHI-certified Air Handling Units with Heat Recovery
24
12 2020‐08‐19
PHI Certification of recovery ventilators
25
25
PHI Certification Criteria
26
26
13 2020‐08‐19
PHI Certification Criteria
27
27
PHI Certification Waste heat heat recovery effectiveness term
AHRI ASHRAE PHI PHIUS HVI
𝑷𝒆𝒍 𝒄𝒇𝒎 𝑿𝒐𝒂 𝑿𝒔𝒂 𝑿𝒐𝒂 𝑿𝒔𝒂 𝑻𝒓𝒂 𝑻𝒆𝒂 𝒄𝒑 𝜺 𝒔𝒂 𝜺 𝜺 𝑚̇ 𝑻 𝑻 𝒄𝒇𝒎𝒎𝒊𝒏 𝑿𝒐𝒂 𝑿𝒓𝒂 𝑿𝒐𝒂 𝑿𝒓𝒂 𝒓𝒂 𝒐𝒂
No minimum No minimum 75% minimum 83%-94% minimum No minimum effectiveness effectiveness effectiveness1 effectiveness2 effectiveness
1. www.passivehouse.com
2. http://www.phius.org/documents/PHIUS%20HRV%20ERV%20certification%20program%20v0.8.pdf
28
28
14 2020‐08‐19
PHI Certification Air handling unit electrical efficiency
Specific electrical power Pel SI ≤0.45 Wh/m3 IP ≤0.765 W/CFM
Electrical power (W) measured during thermodynamic testing, sum of: ①supply fan ④ ②exhaust fan ② ③energy recovery wheel motor ④control devices
③ ①
29
29
PHI Certification Air handling unit electrical efficiency – example of energy benefits
Selection PHI-certified AHU AHRI-certified AHU Airflow (CFM) 3450 3450 Size 35 20 Specific electrical power (W/CFM) 0.62 1.03 (+66%)
30
30
15 2020‐08‐19
PHI Certification Air handling unit leakage
Leakage <3%
Exhaust/Supply Cross-contamination
31
31
PHI Certification Air handling unit comfort
Supply Air ≥61.7°F temperature When Outside Air = 14°F temperature
Exhaust Air (EA) Return Air (RA) 14°F Outside Air (OA) Supply Air (SA) 61.7°F
Outside Inside
32
32
16 2020‐08‐19
PHI Certification Air handling unit airflow range
Supply Air flow range 315 to 5300 CFM When tested at External pressure 0.9 to 1.5 inWC
Exhaust Air (EA) Return Air (RA) Outside Air (OA) Supply Air (SA)
Outside Inside
33
33
PHI Certification Automatic controls to Avoid Excess Negative Pressurization
CAUSES: ERV1 • uneven filter loading • opening doors/windows • wind pressure • temperature differences
COMPLICATIONS: Air entering via infiltration is unconditioned: • leads to unpredictable comfort • eventually consumes HVAC energy
PHI-required REMEDY: self-balancing controls
34
17 2020‐08‐19
PHI Certification Automatic controls to Avoid Excess Positive Pressurization
CAUSES: • uneven filter loading ERV1 • opening doors/windows • wind pressure • temperature differences
COMPLICATIONS: Conditioned forced out of building • Wastes air handler energy • May force moisture into building material • more difficult to maintain comfort
PHI-required REMEDY: self-balancing controls
35
Question 2
• Name 2 of 5 criteria for achieving PHI certification for ERV
36
36
18 2020‐08‐19
Integrating HVAC into Passive Buildings
37
PASSIVE HOUSE ERV CERTIFICATION REDUCED ANNUAL ENERGY CONSUMPTION
ERV selected Annual Energy lowest PHI- VALUE of Consumption first cost certified PHI-certification (kWh) ERV (kWh) Fans (3450 CFM) 10,396 6,235 41% less fan Recovery Wheel 146 146 No change Cooling 7,419 7,128 4% less cooling
Heating 23,790 24,402 3% more (reheat) School and Gym Passive House Certified Energy Recovery Air Handlers Moisture control 1,268 997 21% less moisture control TOTAL 43,020 38,908 9.6% less Total Energy use
38 Integrating HVAC into Large Passive House Building Design
38
19 2020‐08‐19
HVAC INTEGRATION Reference Standards
Standard Informs UL/ULc Addresses North American requirements for overall life safety ISO 9001 Manufacturer quality assurance ISO 14001 Environmental quality assurance, basis of Product Declarations used for LEED certification, self-declarations for WELL certification ASHRAE 189 Minimum requirements for high-performance green buildings. ASHRAE 90.1 Minimum whole-building energy performance requirements, non-residental ASHRAE 90.2 Minimum whole-building energy performance requirements, residental ASHRAE 62.1 Minimum ventilation rates and other measures to provide indoor air quality ASHRAE 62.2 Minimum ventilation rates and other measures to provide indoor air quality
*Passive House certification is not a substitute for UL/ETL safety listing in North America. UL/ETL may be required on Passive House projects. Check with your local code authority.
39 Integrating HVAC into Large Passive House Building Design
39
HVAC INTEGRATION
PHI ERV protocol
PHI certification tool
Passive House Planning Package (PHPP) • Complies with ASHRAE Standard 140‐2017 ‐‐ Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs (ANSI Approved)
Kindergarten Passive House Certified Energy Recovery Air Handlers 40 Integrating HVAC into Large Passive House Building Design
40
20 2020‐08‐19
ERV INTEGRATION Air Flowrates
• Specify Supply Air flowrates meeting minimum applicable requirements of: • ASHRAE 62.1 (non‐residential) • ASHRAE 62.2 (residential) • local code • Passive House • Consider airflow modes for enhanced energy savings and comfort
Exhaust Air (EA) Return Air (RA) Outside Air (OA) Supply Air (SA)
Outside Inside 41 Integrating HVAC into Large Passive House Building Design
41
ERV INTEGRATION PROVIDE OCCUPANCY CONTROL
• Maximize energy savings by equipping building with unoccupied and free‐cooling mode capabilities • Maximize comfort by equipping building with Boost mode capabilities
Exhaust Air (EA) Return Air (RA) Outside Air (OA) Supply Air (SA)
Outside Inside 42 Integrating HVAC into Large Passive House Building Design
42
21 2020‐08‐19
ERV INTEGRATION Centralized or Decentralized?
Centralized Decentralized First cost, total Varies - Requires project team review ERV Fewer more costly units More less costly units Duct Less More MEP connections Less More
43
ERV INTEGRATION Centralized or Decentralized?
OPERATION Centralized Decentralized Proximity Remote Near occupants Duct length Long, consuming more fan energy Short, consuming less fan energy Sound attenuation Benefits from duct network More critical, possibly additive MEP connections few many
44
22 2020‐08‐19
ERV INTEGRATION Centralized or Decentralized Ventilation?
Centralized Decentralized Zone Control shared individual Zone Metering difficult simpler Maintenance Least Most Impact of TFA Concentrated distributed
45
ERV INTEGRATION Centralized Ventilation
ERV1
PENETRATIONS ERV1 Outside Air 1 Exhaust Air 1 Total 2
46 Integrating HVAC into Large Passive House Building Design
46
23 2020‐08‐19
ERV INTEGRATION Decentralized Ventilation, Partial
ERV1 ERV2
PENETRATIONS ERV1 ERV2 Total Outside Air 1 1 2 Exhaust Air 1 1 2 Total 2 2 4
47 Integrating HVAC into Large Passive House Building Design
47
ERV INTEGRATION Decentralized Ventilation, maximum
ERV1 ERV2
ERV3 ERV4
PENETRATIONS ERV1‐6
ERV5 ERV6 Outside Air 6 Exhaust Air 6 Total 12
48 Integrating HVAC into Large Passive House Building Design
48
24 2020‐08‐19
ERV INTEGRATION DESIGN LOW PRESSURE DUCT SYSTEMS
• Target ~1.25 IN WC ESP max, including accessories • Target 400 to 600 FPM duct velocity
𝑃𝑡 𝑃𝑣 𝑃𝑠 Where: Pt = Total Pressure resulting from duct design = total pressure required of ERV Pv = Velocity Pressure = relates to the velocity of air in the duct Ps = Static Pressure, accounts for losses due to duct accessories selected, duct leaks, thermal gravity effects
49 Integrating HVAC into Large Passive House Building Design
49
ERV INTEGRATION DESIGN LOW PRESSURE DUCT SYSTEMS
• Consider large ducts to make most of available air handler pressure • Consider cascading (directed) airflow using transfer grilles instead of ducts where possible
50 Integrating HVAC into Large Passive House Building Design
50
25 2020‐08‐19
ERV INTEGRATION location
Indoor installation Outdoor installation • No thermal bridge risk • Thermal bridge risk • Insulate outside and exhaust air ducts • Insulate supply and return air ducts • Consumes valuable Total Floor Area • Maximizes Total Floor Area
51 Integrating HVAC into Large Passive House Building Design
51
Question 3
• Name the airflow mode common in Passive House buildings, used to provide additional occupant comfort
52
52
26 2020‐08‐19
Passive Building HVAC in New England
Reference Projects with PHI-certified ERU
53
NEW ENGLAND REFERENCE 1 Wheaton College Dormitory • 45,000 ft2 • Continuous Ventilation: • ERU‐1, 2520 CFM • ERU‐2, 1250 CFM • ERU‐3, 1800 CFM • Heat Recovery Effectiveness (PHI) • ERU‐1, 82% (86% with balanced flow) • ERU‐2, 78% (86.5% with balanced flow) • ERU‐3, 81% (86.5% with balanced flow) AHA Consulting Engineers • ERU Electrical Efficiency • ERU‐1, 0.52 W/CFM • ERU‐2, 0.50 W/CFM • ERU‐3, 0.53 W/CFM • Post‐Heating: VRF 54 Integrating HVAC into Large Passive House Building Design • Post‐Cooling: chilled water
54
27 2020‐08‐19
NEW ENGLAND REFERENCE 1 Wheaton College Dormitory
55
NEW ENGLAND REFERENCE 2 Williams College Dormitory • 17,000 ft2 • Continuous Ventilation: (1) ERV, 2340 CFM • Heat Recovery Effectiveness (PHI) • 81% (86.5% with balanced flow) • 7degF design day: 58degF SA • ERV Electrical Efficiency • 0.57 W/CFM • Post‐Heating: Heat Pump + EDH • Post‐Cooling: Heat Pump
Vanderweil Engineers
56 Integrating HVAC into Large Passive House Building Design
56
28 2020‐08‐19
NEW ENGLAND REFERENCE 2 Williams College Dormitory
57
NEW ENGLAND REFERENCE 3 Meriden Commons • Mixed use • Continuous Ventilation: (1) ERU, 4710 CFM • Heat Recovery Effectiveness (PHI) • 86.5% • ERV Electrical Efficiency • 0.7 W/CFM
McHugh Engineering
58 Integrating HVAC into Large Passive House Building Design
58
29 2020‐08‐19
NEW ENGLAND REFERENCE 3 Meriden Commons
59
Question 4
• Name 2 ERV performance measure to schedule on Passive House projects
60
60
30 2020‐08‐19
Benefits of applying PHI-certified air handling unit 1. Reduce energy consumption! 2. Third-party verification of superior energy efficiency and resilience 3. Simplifies energy balance modelling 4. Avoids costly and unpredictable in-situ ERV testing and documentation 5. Avoid derating penalties at final project submission 6. Accepted by Passive House certifying bodies
61 Integrating HVAC into Large Passive House Building Design
61
Resources to take away
Learn more!
62 Integrating HVAC into Large Passive House Building Design
62
31 2020‐08‐19
This concludes the Continuing Education Systems and PHI Course.
Mike Woolsey [email protected] swegon.com +1 612 685 6519 (mobile/sms)
63
64
32