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Pinnacle Homes T-Mass Wall Performance and Rate Structure Analysis. ConSol. Introduction. T-Mass Wall Performance and Peak Impact Rate Structure Analysis Next Steps. Center for Energy Research. Pinnacle. HOMES. Participants and Partners. BIRA Team Pinnacle Homes
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Pinnacle HomesT-Mass Wall Performance and Rate Structure Analysis ConSol
Introduction • T-Mass Wall Performance and Peak Impact • Rate Structure Analysis • Next Steps
Center for Energy Research Pinnacle HOMES Participants and Partners • BIRA Team • Pinnacle Homes • University of Nevada at Las Vegas • Paragon Consulting
The Vinings-- Pinnacle HomesLas Vegas, NV • A highly energy efficient “T-Mass” insulated concrete exterior wall system developed by the Dow Corporation and developed by Precast Technologies. • -A CopperSun solar water heating system looped into the heating system minimizing natural gas consumption for hot water heating. • -A Noritz “tankless” hot water heater. • -Approximately 400 square feet of roof-mounted photovoltaic panels rated at 5.28KW manufactured by GE Energy to generate electricity during low usage periods. Electricity will be fed back onto Nevada Power's grid, helping offset energy use. • -A 19 SEER water-cooled air conditioning condensing unit manufactured by Freus. • -Energy efficient vinyl framed windows with Low “E” glass. • -PolarPly reflective roof sheeting. • -Energy Star rated light fixtures with highly efficient fluorescent bulbs. • -Energy Star rated GE appliances.
Construction Baseline house (left) and ZEH house (right) during construction Erection of T-Mass walls
T-Mass Wall • Syrofoam with connectors made of glass and vinyl ester polymer with low thermal conductivity • 2 inches of syrofoam extruded polystyrene and polyiosocyanurate rigid board insulation • Rated at R-value of 5 hr-ft2-F/BTU per inch • Cross section of T-Mass Wall • Density of 130 lb/ft3; specific heat of 0.22 Btu/lboF • Conductivity of 1.04 Btu/hr-ft2-F per inch • Outer wall is 2” of concrete; Inner wall is 4” of concrete
Simulated Average Wall Loads • Both walls are rated at R-12 • Average reduction in wall load of approximately 40% • Stick frame would require an overall R-18 for the same performance (with R-30-35 rated insulation)
Simulated Total Peak Loads • 10% reduction between T-Mass and Normal Walls • 0.5 Ton smaller HVAC unit • Peak Load shift to 5 or 6 PM vs. 3 or 4 PM • Stable indoor ambient temperature
Real Usage Data: ZEH vs. Baseline T-mass walls reduces total power use and shifts the peak cooling load to later when electricity costs are reduced
Monthly Average Daily Temperature Range • Average interior temperature fluctuations of north and west walls: October 2005 to February 2006 • ZEH wall vary by 1-2 degrees • Normal walls vary from 3 – 7.45 degrees
Simulated Peak vs. Non-Peak kWh UseJuly - August • 75° set point • ZEH shifts load to off-peak hours • ZEH uses 14.5% less energy overall
Energy Rate Comparison • TOU rate results in higher monthly costs • ZEH offsets peak, but not enough to overcome cost of the TOU structure
Annual Cooling Energy Use Comparison • TOU rates are lower in the winter months • Impact over the entire year are more significant • With the same cooling systems, a 10% reduction due to walls alone
Annual Cooling Energy Cost • TOU costs more for either home on an annual basis • ZEH costs is $1 more per year • On a cooling schedule (e.g., programmable thermostat), the ZEH home would have a greater savings • If Nevada Power discontinued TOU fee of $1.30/month, costs would be less for the entire year (even with the AC running unscheduled)
Next Steps • On-going analysis of wall performance • Analysis of contribution of foundation slab and ground coupling (e.g., impact of perimeter insulation) • Comparison of performance to Borrego Springs, CA
Conclusions and Next Steps • T-Mass walls reduced total power use and shift peak loads • Properly managed energy conservation (e.g., setback thermostats) can multiply the rate structure impact • TOU rate can be made an effective energy conservation tool when combined with an aggressive consumer program including setback thermostats and reduced program fees