The Ad-Hoc Passive House. Paul W Panish

Transcription

1 The Ad-Hoc Passive House Paul W Panish

2 Beaton Residence, Shrewsbury MA Architect Builder/Owner Passive House Consultants Mark Yanowitz Verdeco Designs, LLC Matthew Beaton Beaton Construction, LLC Paul W Panish DEAP Energy Group, LLC

3 Synopsis Project Sequence Ramifications of accelerated planning and on-the-fly design Building Characteristics Performance (May September 2011) Issues to be confronted

4 Initial Design Concept Deep Porch Overhang, Shading to South Self Shading 'L' Building Shape Glazing Balance Full Basement partial living space Central Mass Wall Thermal Bridge

5 Revised Design Proposal Retained high ceilings on first floor. Mass wall in basement removed. Reduced number of doors. Adjusted glazing balance, reduced number of glazed units on non-southerly exposures. Rear porch modified to all-season enclosed design with chunk-wood stove (not within thermal envelope, usable as convective heating source)

6 Comparative Demand Initial Design Final Design Specific Space Heat Demand: 5.55 kbtu/(ft²yr) Pressurization Test Result: 0.6 ACH Specific Primary Energy Demand (DHW, Heating, Cooling, Auxiliary and Household Electricity): Specific Primary Energy Demand (DHW, Heating and Auxiliary Electricity): kbtu/(ft²yr) kbtu/(ft²yr) Specific Primary Energy Demand Energy Conservation by Solar Electricity: 0 kbtu/(ft²yr) Heating Load: 4 BTU/(ft 2 hr) Frequency of Overheating: 37 % Specific Useful Cooling Energy Demand: kbtu/(ft²yr) Cooling Load: 2 BTU/(ft 2 hr)

7 Footing Support and Insulation Detail

8 Construction Details Envelope IP (R-Value) Basement Foundation Walls 51.8 Slab Floor 41.3 First Floor Framed Walls 65.7 Second Floor Framed Walls 58.2 Ceiling (main) (*80) Glazing IP (U) SHGC North, East, West, AGC Comfort E2 Triple-2 Argon S.S South AGC Comfort E2 Triple-1 Argon S.S South Doors Thermotech 322 Gain Ventilation IP (CFM) Recoupaerator 200 DX, 82.5% Effective 139 HSPF Heating and Cooling System Zone IV (V) SEER Mitsubishi MXZ-3A30NA, 2 Heads, Non-Ducted 10 (7.5) 16

9 Summer Solstice

10 Monitoring System Electrical Powerhouse Dynamics emonitor 24 Circuits, Insufficient to cover entire electrical panel Homeowner installed (cost saving measure) Plan to monitor most heavily used circuits Environmental Onset Hobo Data Loggers Temperature/Humidity Only 6 Interior locations on all floors plus ambient exterior conditions

11 Temperature Room Temperature Variation Living Room Master Bedroom South Bedroom Basement Master Bath Feb 18-Mar 7-Apr 27-Apr 17-May 6-Jun 26-Jun 16-Jul 5-Aug 25-Aug 14-Sep

12 RH % ASHRAE Comfort Zone Living Room Comfort Zone April - August Temp/RH Clo 1.0 Clo Temp

13 Temperature Watt Hours Cooling Demand vs Ambient Temp Ambient Temp Living Room Temp Heat Pump /18 4/7 4/27 5/17 6/6 6/26 7/16 8/5 8/25 9/14 10/4

14 kwh May September Projected vs Actual Consumption Percent of Projected Demand 5% 49% 14% Cooling DHW 46% Electricity (Aux+Plug) Percent of Actual Demand Projected vs Actual Consumption Cooling DHW Electricity (Aux+Plug) Projected Energy for Period Actual Consumption kwh 16% Cooling DHW 70% Electricity (Aux+Plug)

15 kwh Significant Loads by Month May June July August September DHW Heat Pump Dryer ERV Office LR/TV Sump Refrig Lights Non-Mon

16 Excess Consumption Evaluation ERV 72% Refrigeration 104% Clothes Drying 75% Lighting 560% (definite problem, but not a dominant load) Consumer Appliances/Entertainment Unmonitored Loads Comparable to Appliance/Entertainment Load

17 Entertainment/Consumer Appliance Loads Large Screen Plasma Television with DVR 600 Watts powered on (average 6 hours/day) 100 Watts idle (DVR, Network ) Other Plug Loads Office Equipment Misc. Household

18 Percent RH Unmonitored Loads Induction Cooktop and Oven (Aux. Energy) Freezer not accounted for in planning Transfer of Sump to Unmonitored Circuit Basement Dehumidifier Subjective need? Basement Humidity /26 4/17 6/6 7/26 9/14

19 Additional Internal Loads PHPP Internal Heat Gains (Electrical) are not linked to Heating and Cooling Consumption Sheets. Internal Load Comparison PHPP Default 2.1 W/sq.m. = 0.67 Btu/hr-sq.ft. = W/sq.ft. Total Int. Load Modeled = 621 Watts Continuous Actual Internal Loads 1061 Watts Continuous Over 5 COP of 4 = 396 additional kwh of cooling (out of 737 kwh total)

20 Solutions? Sump Pump Proposed high efficiency DC pump for low flow use, AC pump cut-in for high volume. Entertainment System Reconfigure for less run time? Destroy Plasma TV... Owner Education. Freezer Replace with more efficient unit. Owner Education. Dehumidifier Unnecessary for current conditions. Automate operation or allow for manual monitoring of conditions. Owner Education. Lighting Reduce use of area lighting. Owner Education.

21 Modeling Estimates Thomas Green from an interview with Martin Holladay, Green Building Advisor: At the Riverdale NetZero project in Edmonton Energy use for lights and appliances was more than predicted. These days, new homes have a lot of lights. Our models may not accurately account for modern lifestyles with modern electronics. Homeowners are not necessarily being as energy efficient as predicted.

22 Projected Energy Consumption Assuming no Changes Modified Yearly Estimates PHPP kwh/yr Current Actual % of Projected Projected Annual Consumption kwh/yr Cooling % 746 Heating % 1911 DHW % 2547 Electrical % 9169 Total Projected Annual Site Energy 14,373 Total Projected Annual Primary Source Energy 38,808 kwh/sq.ft.-yr kbtu/sq.ft-yr Normalized Primary Energy Values

23 Lessons for PH Planning Front-load design process Incremental decisions lead to over-design and additional cost. Work with design team to reduce area lighting, increase task lighting, and improve monitors that will be useful to, and used by occupants Site Considerations Test pit for ground water level for all basement installations. No basements where drain to air is unavailable without accounting for potential pumping loads. Shading from tree canopy during summer months is tricky, less than expected, and results in higher cooling loads. Check if external tools (Solar Pathfinder) are more accurate predictors. Monitoring Full coverage on electrical panel whenever possible (no need for massive electrical panels). No client installations.

24 Future Considerations Increased emphasis on Primary Energy vs Envelope Loads. Revisit PHPP default values for Electricity and Aux Energy Sheets. Consider renewable generation offsets for Primary Energy. Establish derate for time of generation vs time of use. Cold climate considerations, retain thermal bridging and comfort criteria. Re-evaluate relative priorities of other factors.