NET-ZERO-ENERGY RESIDENCE :: SEATTLE, WA Architecture 632: High-Performance Buildings; Ball State University; Fall 2015; Christopher Padgett

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1 The project investigated high-performance building design strategies that led to a net-zero energy, single-family residence. Extensive research into passive systems paired with parametric analysis tools provided insight to guide thoughtful design strategies. The residence started from a basic, conceptual stage then progressed throughout the semester. The residence floor area is roughly 1,500 SF and is located in Seattle, WA. The house will be built on a floating platform that is anchored over Lake Washington. The main strategy for placing the house on a floating platform is to have the structure move with the water level. Sea level rise caused by melting ice caps could affect the Seattle area. In addition, the floating house will take advantage of the site by producing on-site renewable energy through a pico-hydro system. Additionally, recycling water through a filtration system could provide an ample amount of potable water. N ROOF/FLOOR :: R = 34 The upper, sloped roof will have solar collectors to heat water and the trusses extend out to create a shading area on the upper deck. Also, clerestory windows will be included to increase ventilation and allow light to penetrate deep into the residence. The upper deck will allow for views and entertainment. The residence will utilize high performance construction assemblies to minimize energy use and increase effeciency. The walls, roof, and floor are designed to achieve a high R-value to reduce energy requirements to maintain indoor comfort levels. The walls will utilize a double-stud system with cellulose insulation and 24 O.C. stud spacing to increase the thermal resistance. The roof will consist of I-joists with a dual insulation system of cellulose and foam. Due to the residence floating on water, the floor will mimic the construction assembly of the roof to increase thermal properties. The doors and windows are ENERGY STAR Qualified Northern Zone grade. The walls, roof, and floor will utilize a high thermal mass to provide a high R-value with minimal thermal bridging. The assemblies include cellulose insulation due to its durability, moisture permeability, anti-mold growth, and decreased flame spread. Cellulose Insulation = R-3.7/inch UPPER DECK BATHROOM PANTRY BEDROOM LIVING ROOM PATIO DINING ROOM FIRST LEVEL FLOOR PLAN SECOND LEVEL FLOOR PLAN SCALE: 1/16 = 1 SCALE: 1/16 = 1 WALL :: R = 36 ABOVE: ThermaStar by Pella 10 Series Wood Double Pane Annealed New Construction Single Hung Window LEFT: Pella 450 Series in Clear Glass White Wood Sliding Patio Door WINDOWS :: U = 0.3 SHGC = 0.3

2 Climate Consultant was utilized to study specific climate and design strategies for Seattle, WA. The area is in climate zone 4 and is considered oceanic or temperate marine, with cool, wet winters and warm, relatively dry summers. The building heat loss was reduced through a well-insulated enclosure system. The walls will utilize a double-wall system with cellulose insulation and 24 O.C. stud spacing to increase thermal resistance. The walls will have an R-value of (36). The roof and floor will be constructed with I-joists that includes a dual insulation system of cellulose and foam. The foam insulation will act as a water barrier to protect the cellulose from mold-growth. The roof and floor will have an R-value of (52), illustrated on the previous page. The triple-pane, double-hung windows will be Pella NaturalSun Low-E IG with a U-factor of (0.27) and SHGC of (0.43). The triple-pane, sliding patio doors will be Pella NaturalSun Low-E IG with a U-factor of (0.29) and SHGC of (0.45). A water-source heat pump will provide efficient heating on the few days heating may be required. The building heat gain was mitigated through a cross-ventilation system with double-hung and clerestory windows. The air will flow from low to high to push warmer air outdoors. Also, a water-source heat pump will provide efficient cooling on the few days cooling may be required. The building lighting loads was reduced through thoughtful placement of windows, especially in active daytime areas. Clerestory windows were placed to bring daylight into the kitchen and dining room. Sliding patio doors were placed in the master bedroom and living room. Also, fwindows were placed throughout to increase daylight penetration. The double-hung windows will have a VLT of (52). The sliding patio doors will have a VLT of (51). Plug loads were reduced through the enclosure system. The high thermal resistance of the walls, roof and floor will maintain indoor temperatures as outdoor temperatures fluctuate. Less energy will be required to heat or cool the indoor environment for thermal comfort. The placement of windows in active daytime areas will reduce the need for electrical lighting. During the winter, a stone-faced fireplace will provide surface mass to store winter daytime solar gain. Also, the fireplace will provide a central heat source. Finally, the upper, sloped roof will have solar collectors to heat water. The production of on-site energy will come from a pico-hydro system that uses that natural flow of water to produce electrical power. The water turbine converts the flow and pressure of water to mechanical energy. The turbine turns a generator, which is then connected to electrical loads. The pico-hydro system could produce 5 kw to 100 kw of electricity. Balance Point Temperature calculation: Ubldg = Uwall + Uroof + Uglzg + Ugrnd +Uvent = = Q IHG = Qpeople + Qlight + Q equip = = 7.81 DTocc = Q IHG Ubldg = = 19.7 Thermostat = 70 Tbalance = Tthermostat - DTocc = = 50.3 The balance point temperature for the residence was calculated to find the base temperature to then calculate heating degree days to anticipate annual energy demand to heat the building. The design produces a balance point temperature of (50) degrees. Balance Point Temperature Diagram

3 A comparative analysis was performed in HEED to explore various outcomes when design strategies were augmented for better results. Scheme 3 was used as a baseline and schemes 4 and 5 were manipulated for better performance. Scheme 3: -Window: Clear double pane low-e in insulated fiberglass/vinyl frame (U= 0.32; SHGC = 0.46; Tvis = 0.58) -Level of Insulation = Current code wood frame wall: cavity + continuous insulation (wall R13-R5 or R15+R4; ceiling R38; slab F0) -Fan Forced Ventilation: Large whole house fan (up to 30 air changes/hour): assume strong air velocity, smart thermostat controlled exhaust fan -Heating: Best available furnace, condensing furnace (97% AFUE, Annual Fuel Utilization Efficiency) -Cooling: Best available conditioner, split system (19.5 SEER, seasonal energy efficiency ratio) -Operable Shading: Overhangs* (default condition) are fixed all year, or there are no overhangs, also no interior shades or venetian blinds Scheme 4: -Window: Clear argon filled double pane low-e squared in insulated vinyl frame (U=0.3; SHGC = 0.25; Tvis = 0.52) -Level of Insulation: Insulation upgrade to 1.5 times current code R-values -Infiltration: HERS verified air sealed and quality insulation installation (QII): 1.5 SLA; 3.0 ACH50 -Fan Forced Ventilation: Ceiling fans- smart thermostat and occupant sensors (means only one fan running per occupant) -Heating: Electric furnace or baseboards (HSPF = 3.41, Heating System Performance Factor) -Cooling: No air conditioner (and no Heat Pump) -Operable Shading: Light translucent interior shades (25%) close to block sun any hour when indoor reached 3-degrees below comfort zone Scheme 5: -Level of Insulation: Super insulation to 2.0 times current code R-values -Infiltration: Passive house standard (tm) extremely tight air sealing requirement: 0.3 SLA; 0.6 ACH50 -Operable Shading: White opaque interior shades (0%) automated hourly for summer shading or retract to maximize solar gain -Hot Water System: Electrical only -PV System: 7 kw -ve: +ve: I/O I/O i/f: i: I/O p: I/Ou: I/Oo: I/O REVISION 2 DESIGN REVISION 1 DESIGN BASELINE DESIGN The BEopt (Building Energy Optimization) software was utilized to evaluate the building design with various energy and cost options. Design strategies were manipulated and evaluated for energy-savings toward a net-zero-energy residence. In addition, associated cost of each package could be given to further evaluate a cost-impact analysis. EPA has determined that source energy is the most equitable unit of evaluation. Source energy refers to the total amount of raw fuel that is required to operate the building. It provides a complete assessment of energy efficiency in a building by taking into account all energy. Baseline Revision 1 Revision Revision 1 Modifications: PV Tilt: Roof Pitch to Latitude +15 degrees Plug Loads: Average Use Appliances & Fixtures: Top Freezer - EF 17.6 to EF 17.6, 95% Usage Cooking Range - Electric to Electric, 80% Usage Dishwasher Rated kwh to 318 Rated kwh, 80% Usage Clothes Washer - Standard to Energy Star Clothes Dryer - Electric to Electric, 80% Usage Hot Water - Average Use to Half Use Revision 2 Modifications: Heating System: Air Source Heat Pump - SEER 22, 10 HSP Plug Loads: Average Use to Half Use 81.3

4 Pico-Hydro System + The renewable energy system for the project will consist of a pico- hydro system that utilizes the water flow rate of Lake Washington. The analysis tool called RETSreen is a clean energy management software provided by Natural Resources Canada. The analysis tool provides system performance data for a wide range of renewable energy systems including a hydro turbine configuration. Due to the complexity of the software, I uploaded a case study that analyzes a 4.0 kw micro-hydro system for a residence and changed the climate data location to Seattle/Tacoma. The system generates power by the energy systems and design stream ngine and stores it in batteries as direct current (DC). Power is supplied by the batteries, which store energy during periods of low consumption for use in periods where consumption exceeds the generation rate. Appliances can be used that operate directly from the batteries through an inverter, converting DC to AC power. The turbine supplies up to 1.5 kw for battery charging. However, energy production could be increased to 3 to 4 kw by employing 2 or 3 jets. Mechanical Room Inverter + Battery + Tech. Hydro Power Category: Large Hydro Power >30 MW Small Hydro Power <30 MW but >1 MW Mini Hydro Power <1 MW but >100 kw Summary Resource Assessment + Hydro Turbine The case study proposes that the homeowner s electricity requirements average roughly 5 kwh per day. The peak load is roughly 3 kw. The case study water flow exceeeds 1.6 ft3/second through the year. The purchase of the micro-hydro turbine, an alternator, and a Thompson and Howe load controller would total around $7,500. Micro Hydro Power <100 kw but >10 kw Pico Hydro Power <10 kw

5 DESIGN PROGRESSION SUMMARY: Initial Design Strategies: - Wall: Double-wall system with cellulose insulation (R-value 36); 24 O.C. stud spacing - Roof/Floor: I-joists with a dual insulation system of cellulose and foam (R-value 52); 24 O.C. - Windows: Triple-pane, double-hung (U-factor 0.27; SHGC 0.43; VLT 52) - Patio Doors: Triple-pane (U-factor 0.29; SHGC 0.45; VLT 51) - Passive Cooling: Cross-ventilation system pushing warmer air from low to high then outdoors - Passive Heating: Surface mass to store winter daytime solar gain and a central heat source - Mechanical System: Water-source heat pump - On-Site Energy Production: Pico-hydro (water turbine) system; solar collectors -Orientation: Maximize winter sun exposure by facing glass area south -Plug-Loads: Organize floorplan so sun penetrates daytime use spaces and reduces electrical lighting Further Design Strategies from HEED Analysis: - Level of Insulation: Super insulation to 2.0 times current code R-values - Infiltration: Passive house standard (tm) extremely tight air sealing requirement: 0.3 SLA; 0.6 ACH50 - Operable Shading: White opaque interior shades (0%) automated hourly for shading or solar gain - Fan-Forced Ventilation: Ceiling fans with smart thermostat and occupant sensors - Hot Water System: Electrical only - On-Site Energy Production: 7 kw NET-ZERO ENERGY Further Design Strategies from BEopt Analysis: - PV Tilt: Roof pitch to Latitude +15 degrees (substitution for pico-hydro system) - Plug Loads: Average Use - Appliance & Fixtures: Top Freezer - EF 17.6 to EF 17.6, 95% Usage Cooking Range - Electric to Electric, 80% Usage Dishwasher Rated kwh to 318 Rated kwh, 80% Usage Clothes Washer - Standard to Energy Star Clothes Dryer - Electric to Electric, 80% Usage Hot Water - Average Use to Half Use - Heating System: Air Source Heat Pump - SEER 22, 10 HSP - Plug Loads: Average Use to Half Use The residence consumes 4,488 kwh of electricity annually. The PV system generates 8,788 kwh of electricity annually. Therefore, the residence is not only net-zero but could be regenerative if the on-site energy production system is tied into the utility grid. Additionally, the site net carbon dioxided produced is -6,394 pounds annually. Therefore, the residence is also carbon neutral.