Ventilation Design Considerations for Passive House Multifamily Residential Buildings
Hugh Crowther Vice President, Engineering [email protected]
October 24, 2017
1 Ventilation Design Considerations for Passive House Multifamily Residential Buildings AGENDA
1 Ventilation Unit Primer 2 Centralized vs. Decentralized Ventilation Design 3 Winter Humidity Issues 4 Energy Impact - Sensible vs. Enthalpy Energy Recovery 5 Summary 6 Questions
2 Ventilation Design Considerations for Passive House Multifamily Residential Buildings PART 1 VENTILATION UNIT PRIMER
Integrating Swegon GOLD DOAS units with Mitsubishi VRF
3 Ventilation Design Considerations for Passive House Multifamily Residential Buildings ENERGY RECOVERY VENTILATION UNITS
Sensible Energy Recovery Total (Enthalpy) Energy Recovery > Recover heat but not humidity > Recover heat and humidity > Raise temperature in winter but not increase humidity ratio > Raise temperature and humidity in winter, cool and dehumidify in summer > Plate, wheel, heat pipe, run around loops Enthalpy plate enthalpy wheel > Sometimes called Heat Recovery Ventilators (HRVs) > > Sometimes called Energy Recovery Ventilators (ERVs)
4 Ventilation Design Considerations for Passive House Multifamily Residential Buildings CENTRALIZED VENTILATION UNIT EXAMPLES
5 Ventilation Design Considerations for Passive House Multifamily Residential Buildings DECENTRALIZED VENTILATION UNIT – WALL MOUNTED
6 Ventilation Design Considerations for Passive House Multifamily Residential Buildings DECENTRALIZED VENTILATION UNITS – CLOSET/CEILING MOUNTED
7 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – PLATE TYPE
8 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
9 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
10 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
11 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
12 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
13 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
14 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
15 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
16 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
17 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VENTILATION UNIT – WHEEL TYPE
Exhaust
Extract Outside
Supply
Extract Exhaust Outside Supply
18 Ventilation Design Considerations for Passive House Multifamily Residential Buildings DEFINITION OF EFFICIENCY (EFFECTIVENESS ETC.)
풄풇풎풔풂(푿풐풂 − 푿풔풂) 푿풓풂 − 푿풆풂 + 푷풆풍/풎 · 풄풑 (푿풐풂 − 푿풔풂) 휺 = 휺 = 휺 = 풄풇풎풎풊풏(푿풐풂 − 푿풓풂) (푿풓풂 − 푿풐풂) (푿풐풂 − 푿풓풂)
19 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SENSIBLE ENERGY VENTILATION UNIT (HRV) WINTER OPERATION
Exhaust Air Fan Heat Exchanger Return Air Filter
23°F Exhaust Air (EA) Return Air (RA) 72°F 15°F Outside Air (OA) Supply Air (SA) 65°F
Outside Air Filter Supply Air Fan
Outdoors Indoors
20 Ventilation Design Considerations for Passive House Multifamily Residential Buildings TOTAL ENERGY VENTILATION UNIT (ERV) WINTER OPERATION
Exhaust Air Fan Heat & Moisture Return Air Filter Exchanger
23°F, 81% RH Exhaust Air (EA) Return Air (RA) 72°F, 31% RH 15°F, 82% RH Outside Air (OA) Supply Air (SA) 65°F, 36% RH
Outside Air Filter Supply Air Fan
Outdoors Indoors
PHI Certification values: Certified values, no PHI requirements: > 84% heat recovery efficiency (min 75% required) > 84% moisture recovery efficiency > 0.32 W/CFM (max 0.765 required)
21 Ventilation Design Considerations for Passive House Multifamily Residential Buildings TOTAL ENERGY VENTILATION UNIT (ERV) SUMMER OPERATION
Exhaust Air Fan Heat & Moisture Return Air Filter Exchanger
86°F, 43% RH Exhaust Air (EA) Return Air (RA) 75°F, 43% RH 88°F, 48% RH Outside Air (OA) Supply Air (SA) 77°F, 50% RH
Outside Air Filter Supply Air Fan
Outdoors Indoors
PHI Certification values: Certified values, no PHI requirements: > None (min 75% required) > 84% heat recovery (rejection) efficiency > 0.32 W/CFM (max 0.765 required) > 66% moisture recovery
22 Ventilation Design Considerations for Passive House Multifamily Residential Buildings PART 2 CENTRALIZED VS. DECENTRALIZED VENTILATION DESIGN
Integrating Swegon GOLD DOAS units with Mitsubishi VRF
23 Ventilation Design Considerations for Passive House Multifamily Residential Buildings CENTRALIZED VENTILATION DESIGN, (3) FLOORS, (1) ERV, (2) SHAFTS, (6) LONG DUCT RUNS
Exhaust Air Return Air Outside Air Supply Air
Occupied Space
Occupied Space
PENETRATIONS ERV1 Outside Air 1 Exhaust Air 1 Total 2 Occupied Space
24 Ventilation Design Considerations for Passive House Multifamily Residential Buildings DECENTRALIZED VENTILATION DESIGN (3) FLOORS, (1) ERV/ZONE, (0) SHAFTS, SHORT DUCTS
ERV 1 ERV 2
Occupied Space Occupied Space
ERV 3 ERV 4
Occupied Space Occupied Space
ERV 5 ERV 6 PENETRATIONS ERV1-6 Outside Air 6 Occupied Space Occupied Space Exhaust Air 6 Total 12
25 Ventilation Design Considerations for Passive House Multifamily Residential Buildings ENERGY RECOVERY VENTILATION UNITS
Centralized Decentralized > Maintenance in control of building owner > Operating cost and maintenance is in tenants control > Far fewer envelope penetrations (pressure testing) > No common area duct runs > Generally more efficient (Fans, energy recovery device) DOAS units > Minimal fire damper issues > Equipment noise away from tenants – easier to attenuate > No Common mechanical room requirement – space savings > Doesn’t use up apartment space > Cost advantage - depends > Cost advantage - depends
26 Ventilation Design Considerations for Passive House Multifamily Residential Buildings PART 3 WINTER HUMIDITY ISSUES
Integrating Swegon GOLD DOAS units with Mitsubishi VRF
27 Ventilation Design Considerations for Passive House Multifamily Residential Buildings WINTER HUMIDITY ISSUE
High humidity within apartment in cold weather creates uncomfortable indoor climate can cause condensation to form damage building, mold
28 Ventilation Design Considerations for Passive House Multifamily Residential Buildings CONDENSATION FORMATION
> The colder it gets, the easier humidity will form > The higher the humidity level, the easier humidity will form > Both at the same time is a bad thing > Better glass helps (inside temperature is higher and stays above dew point longer)
29 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SCENARIO 1 – HIGH DENSITY APARTMENT > ASHRAE Std 90.1 and Passive House construction > Sensible (HRV) and Enthalpy (ERV) energy recovery > Decentralized and centralized ventilation
30 Ventilation Design Considerations for Passive House Multifamily Residential Buildings HIGH DENSITY APARTMENT
31 Ventilation Design Considerations for Passive House Multifamily Residential Buildings HIGH DENSITY APARTMENT
> 952 ft² > 3 bedroom, 2 bathroom > Design Occupancy = 4 > Laundry in common area > Ventilation rate = 85 cfm > Std 90.1 Infiltration = 72 cfm > PH Infiltration = 20 cfm
32 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SCENARIO 2 – LOW DENSITY APARTMENT > ASHRAE Std 90.1 and Passive House construction > Sensible (HRV) and Enthalpy (ERV) energy recovery > Decentralized and centralized ventilation
33 Ventilation Design Considerations for Passive House Multifamily Residential Buildings LOW DENSITY APARTMENT
34 Ventilation Design Considerations for Passive House Multifamily Residential Buildings LOW DENSITY APARTMENT
> 853 ft² > 2 bedroom, 2 bathroom > Design Occupancy = 4 > Laundry in apartment > Ventilation rate = 85 cfm > Std 90.1 Infiltration = 141 cfm > PH Infiltration = 39 cfm
35 Ventilation Design Considerations for Passive House Multifamily Residential Buildings ESTIMATING HUMIDITY LOADS
36 Ventilation Design Considerations for Passive House Multifamily Residential Buildings ESTIMATING HUMIDITY LOADS*
Source Pints Grains
5 Minute Shower 0.5 3650
Indoor drying of cloths 4-6 per load 29225-43840 per load
5-7 house plants 1/day 7300/day
Washing Dishes (Dinner, family of 4) 0.7 5100
Cooking (Dinner, Family of 4) 1.2 8770 (1.5 with gas cooktop) (10950 with gas cooktop)
Respiration/Perspiration 0.4/hr 3040/hr
Evaporation, New Construction Materials 10+/day 73000+/day
1 Cord Green Firewood, stoed indoors for 6 mo 400-800 2.9M-5.8M
*Minnesota Extension Service, University of Minnesota
37 Ventilation Design Considerations for Passive House Multifamily Residential Buildings HUMIDITY SOURCE ASSUMPTIONS
High Density High Density High Density 8770 gr/h 59.1 gr/lb 7300 gr/h Low Density Low Density Low Density 8770 gr/h 52.7 gr/lb 3650 gr/h
High Density High Density 5100 gr/h 12160 gr/h Low Density Low Density 5100 gr/h 9120 gr/h
38 Ventilation Design Considerations for Passive House Multifamily Residential Buildings DEHUMIDIFICATION
> Air Infiltration > 0.18 cfm/ft2@ 0.2” wc (Std 90.1) > 0.05 cfm/ft2@ 0.2’wc (PH) > Permeation – ignored > Ventilation air > 85 cfm > Sensible Energy Recovery (dry air) > Total Energy Recovery (retain 80% of moisture)
39 Ventilation Design Considerations for Passive House Multifamily Residential Buildings Sensible (HRV) Energy Recovery
Dehumidification Result Humidity Infiltration Sensible New Hum New Rel. Gain Energy Ratio 72F Hum. at Recovery 72F SCENARIO 1 – HIGH DENSITY, Ventilation DECENTRALIZED VENTILATION gr/hr gr/hr gr/hr gr/lb % Std 90.1 33330 6240 7367 58 50.5 > HIGH DENSITY APARTMENT HAS high Construction internal humidity gain Passive House 33330 1733 7367 66 56.5 > Infiltration from Std 90.1 construction Construction helps dry out space > Tight PH building builds up humidity in Total (ERV) Energy Recovery space > Sensible recovery device recovers heat Dehumidification Result but air is dry – helps dry out space Humidity Infiltration Total Energy New Hum New Rel. > Total energy recovery device recoups Gain Recovery Ratio 72F Hum. at Ventilation 72F 80% of humidity – causes humidity to increase gr/hr gr/hr gr/hr gr/lb % Std 90.1 33330 6240 1473 69 59 Construction Passive House 33330 1733 1473 77 65.7 Construction
40 Ventilation Design Considerations for Passive House Multifamily Residential Buildings Sensible (HRV) Energy Recovery
Dehumidification Result Humidity Infiltration Sensible New Hum New Rel. Gain Energy Ratio 72F Hum. at Recovery 72F SCENARIO 1 – HIGH DENSITY, Ventilation CENTRALIZED VENTILATION gr/hr gr/hr gr/hr gr/lb % Std 90.1 33330 6240 7367 58 50.5 > High Density apartment has high internal Construction humidity gain Passive House 33330 1733 7367 66 56.5 > Infiltration from Std 90.1 construction Construction helps dry out space > Tight PH building builds up humidity in Total (ERV) Energy Recovery space > Centralized sensible energy device Dehumidification Result behaves the same as decentralized Humidity Infiltration Total Energy New Hum New Rel. > Diversity from being connected to Gain Recovery Ratio 72F Hum. at Ventilation 72F multiple apartments reduces increase in RH gr/hr gr/hr gr/hr gr/lb % Std 90.1 33330 6240 2947 66 56.5 Construction Passive House 33330 1733 2947 74 63.6 Construction
41 Ventilation Design Considerations for Passive House Multifamily Residential Buildings Sensible (HRV) Energy Recovery
Dehumidification Result Humidity Infiltration Sensible New Hum New Rel. Gain Energy Ratio 72F Hum. at Recovery 72F SCENARIO 2 – LOW DENSITY, Ventilation DECENTRALIZED VENTILATION gr/hr gr/hr gr/hr gr/lb % Std 90.1 26640 12230 7367 37 31.9 > Low density apartment has 80% Construction humidity gain for same volume Passive House 26640 3397 7367 55 47.2 > Infiltration from Std 90.1 construction Construction helps dry out space > Tight PH building builds up humidity in Total (ERV) Energy Recovery space > Sensible recovery device recovers heat Dehumidification Result but air is dry – helps dry out space Humidity Infiltration Total Energy New Hum New Rel. > Total energy recovery device recoups Gain Recovery Ratio 72F Hum. at Ventilation 72F 80% of humidity – but not to an unacceptable level gr/hr gr/hr gr/hr gr/lb % Std 90.1 26640 12230.4 7367 69 42 Construction Passive House 26640 3397 7367 66 56.5 Construction
42 Ventilation Design Considerations for Passive House Multifamily Residential Buildings Sensible (HRV) Energy Recovery
Dehumidification Result Humidity Infiltration Sensible New Hum New Rel. Gain Energy Ratio 72F Hum. at Recovery 72F SCENARIO 2 – LOW DENSITY, Ventilation CENTRALIZED VENTILATION gr/hr gr/hr gr/hr gr/lb % Std 90.1 26640 12230 7367 37 31.9 > Low density apartment has 80% Construction humidity gain for same volume Passive House 26640 3397 7367 55 47.2 > Infiltration from Std 90.1 construction Construction helps dry out space > Tight PH building builds up humidity in Total (ERV) Energy Recovery space > Centralized sensible energy device Dehumidification Result behaves the same as decentralized Humidity Infiltration Total Energy New Hum New Rel. > Diversity from being connected to Gain Recovery Ratio 72F Hum. at Ventilation 72F multiple apartments and lower humidity gain make total energy preferable gr/hr gr/hr gr/hr gr/lb % Std 90.1 26640 12230.4 7367 66 39.5 Construction Passive House 26640 3397 7367 63 53.9 Construction
43 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SUMMARY
Scenario Density Ventilation Std. Sensible vs. Total New Rel. Hum. At 72F (%)
90.1 Sensible 50.5
Total 59 1 HIGH DECENTRALIZED PH Sensible 56.5
Total 65.7
90.1 Sensible 50.5 Total 56.5 1 HIGH CENTRALIZED PH Sensible 56.5 Total 63.6 90.1 Sensible 31.9 Total 42 2 LOW DECENTRALIZED PH Sensible 47.2 Total 56.5 90.1 Sensible 31.9 Total 39.5 2 LOW CENTRALIZED PH Sensible 47.2 Total 53.9
44 Ventilation Design Considerations for Passive House Multifamily Residential Buildings WINTER HUMIDITY SUMMARY
Passive House Decentralized Total Centralized Ventilation construction is tight Energy Recovery units can help Ventilation has risk Ultra low leakage rates can The diversity from cause humidity to build up Humidity recovery causes connecting to multiple in apartments especially humidity to build up to apartments can reduce high density apartments unacceptable levels. humidity build up and It may not be an issue in allow additional savings low density apartments from total energy recovery
45 Ventilation Design Considerations for Passive House Multifamily Residential Buildings PART 4 ENERGY IMPACT – SENSIBLE VS. ENTHALPY ENERGY RECOVERY
Integrating Swegon GOLD DOAS units with Mitsubishi VRF
46 Ventilation Design Considerations for Passive House Multifamily Residential Buildings ENERGY MODELLING > DOAS unit energy modelling program > Compare two systems side by side > Enthalpy Wheel vs. sensible wheel > Scenario 1 – No cooling, hot water heating > Scenario 2 - VRF DX cooling w/ HGRH and heat pump heating
47 Ventilation Design Considerations for Passive House Multifamily Residential Buildings MODEL SETUP
48 Ventilation Design Considerations for Passive House Multifamily Residential Buildings MODEL SETUP
49 Ventilation Design Considerations for Passive House Multifamily Residential Buildings WHEEL FROST CONTROL
Total recovery much greater than sensible due to lower frost point Wheel speed vs. energy transfer not linear Almost twice winter energy recovery Must slow wheel down to a few rpm to get capacity reduction
50 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SCENARIO 1- NO COOLING
51 Ventilation Design Considerations for Passive House Multifamily Residential Buildings Scenario 2 - VRF Heating and Cooling
52 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VRF – Ventilation Unit Integrated Controls
53 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VRF Electronic Expansion Devices
54 Ventilation Design Considerations for Passive House Multifamily Residential Buildings VRF – Hot Gas Reheat Solution
55 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SCENARIO 2 - VRF COOLING AND HEATING
56 Ventilation Design Considerations for Passive House Multifamily Residential Buildings PART 5 SUMMARY
57 Ventilation Design Considerations for Passive House Multifamily Residential Buildings SUMMARY
Centralized vs. decentralized Passive House construction Total Energy recovery ventilation depends on the and high humidity in winter saves energy and reduces application should be considered operating cost
The are many parameters Be careful with high density Total energy recovers including technical and cost apartments and decentralized 5-15% more sensible that impact this decision. total energy recovery. energy in winter plus Being able to seal the building Centralized total energy maintain indoor humidity. for a pressure test should not recovery should be okay, Low It dehumidifies in summer. be overlooked especially on density apartments should be It reduces size of air tall buildings okay but check! conditioning by 25%
58 Ventilation Design Considerations for Passive House Multifamily Residential Buildings Questions?
59 Ventilation Design Considerations for Passive House Multifamily Residential Buildings