ME, ECE, BE Capstone Design Programs To Predict To Design To Perform R806: Unvented Roof Assembly John Bryan, Cameron Burchak, Justin David, Joseph Henderson, David Miller Sponsors: Mr. Bobby Byrd of RoyOMartin Advisors: Dr. Charalampopoulos, Mr. Gillio P.E. Project Objectives 1) Design a cost effective hybrid unvented roof assembly • efficiently utilizes an under decking radiant barrier • Uses under-sheathing open cell spray foam 2) Address the moisture that gets trapped in the attic. Testing Test 2 identical 8’X8’ scale model Unvented homes Phase I Phase II Correctly sized vs oversized Correctly sized vs Enthalpy Wheel Testing apparatus •Humidistat, Thermocouples, Moisture Meter, Watt meter Background R806 is the residential code on how to properly build and insulate the roof deck of a home Reflective Insulation This is a model of baffle system that has a reflective material attached to it in order create a reflective air gap with an R-value of 9.5. Engineering Specifications • Constraints of R806.5 • Roof deck R-value of at least 38 • Less than 16% moisture content in wood • Utilizes Open Cell Spray Foam and Reflective Insulation Moisture Extraction method for Retrofit Homes New Construction Houses • Designing for new construction the moisture issue can be addressed by proper sizing of the HVAC equipment using a tedious method called Manual J. Timeline and Budget Safety House Conditions Space Attic RH (%) 50 35 Temp (⁰F) 75 5-10 Design Conditions City : Baton Rouge, Louisiana Summer Winter 92⁰F db 77⁰F wb 30⁰F db 1. The desiccant wheel absorbs moisture from the attic airstream. 2. This moisture is released from the wheel into the return air stream 3. Moisture condenses at the evaporator coil. Mechanical Electrical Bio/Chemical Hazard • Motors • Fans • Shock • Fire • VOCs • Wood Rot Engineering Control • Safety Guards • Wire Coating • Secure Connections • Sealed electrical boxes • Control Infiltration • Moisture Removal Behavioral Control • Warning Signs • Warning signs • Smoke detectors N/A Vented • Typically common design • Does not include attic in thermal space • Attic can reach temperatures of 130⁰F • Great Temp difference between attic and space • Moisture is vented out of attic Unvented • Put into Practice in 2006 • Includes Attic in Thermal space • Attic is only 5-10⁰F warmer than set point of space • Duct work is in semi- conditioned space • Moisture gets trapped in attic http://www.buildingscience.com/documents/insights/bsi-074-duct-dynasty Results 40 60 80 100 120 140 160 180 7 9 11 13 15 17 19 21 23 Temperature (F) Time (hrs) Roof Deck Temp Distribution Roof Deck Air Space Insulation Attic Temp Outside Temp 4/2/15 Peak Values Sensor Location f F Outside Temp 87.8 Roof Deck 123.8 Air Space 161.6 Insulation 82.4 Attic Space 75.2 Time: 1:30 PM Building Material, 32% Misc, 16% Spray Foam, 10% Air Conditioner, 10% Remainder, 24% Budget $10,000 Electrical Testing Apparatas Category Amount Building Material $ 3,241.14 Misc. $ 1,615.15 Electrical $ 250.81 Testing Apparatus $ 553.07 Spray Foam $ 1,000.00 Air Conditioner $ 977.51 Remainder $ 2,362 TOTAL $ 7,637 1/3/15 1/30/15 2/30/15 3/21/15 4/15/15 4/22/15 40 45 50 55 60 65 70 75 80 0 100 200 300 400 500 600 700 800 900 1000 Humidity [%] Time [min] Proper Sized System Humidity Attic Space 40 45 50 55 60 65 70 75 80 0 50 100 150 200 250 300 Humidity [%] Time [min] Desiccant Wheel System Attic Space