High Performing Buildings - Spring 2008 - (Page 54) Adding exercise or renewable energy increases results. However, having a personal trainer, or a monitoring and visualization solution, to watch the progress, track results, motivate by showing the progress, refocus efforts when slipping, say what to do next, and say if things are being done right provides the greatest results in the shortest period of time and allows for continuous improvement. All three components helped achieve the net zero electric building. Model Comparisons The building’s electric and gas consumption as well as Btu/ft2 are monitored and recorded. These readings Ferreira constructed 31 Tannery with standard materials and readily available resources. PROJECT COST Total Building Cost $6 million Individual Component Costs (already included in total above) Photovoltaic System Walkways Solar Thermal System Radiant Flooring Additional High-Efficiency HVAC and Controls Systems $1,700,000 $22,000 $15,000 $160,000 $700,000 The total payback for adding solar electric, solar thermal, additional highefficiency systems, and monitoring is approximately five to seven years. This factors in the cost of electricity saved, cost of gas saved, renewable energy credits earned, state rebates and federal tax credits. are compared to DOE 2.1 models for the project, developed prior to construction when the best fit of energy efficiency and renewable energy systems was determined. Energy modeling evaluated the design’s energy efficiency and projected energy requirements. Comparing actual recorded data to DOE models for high-efficiency systems and renewable energy reveals that Ferreira’s natural gas consumption has been reduced by 13% and electric consumption by more than 100%. The performance of 31 Tannery is measured against two energy models: a typical preengineered model or base building and a high performance design model. The base building is constructed using standard techniques and outfitted with conventional energy systems. A high performance design model uses state-of-the-art renewable and energy conservation systems and methods. When compared to the base building, 31 Tannery’s gas consumption was reduced by 77% and electric consumption by 104%. The calculations factor in the use of renewable energy and energy conservation. Grid-Tied Photovoltaics Attached to 31 Tannery’s standing seam metal roof are 1,276 solar photovoltaic panels. Being new construction, rooftop penetrations and systems, such as the rooftop unit (RTU) and shop ventilation system, were kept to the north side of the building to maximize performance of the rooftop solar photovoltaic array. The solar electric system produces on average 500 kWh per day in the winter and 1,300 kWh per day in the summer. On a cloudy or overcast day, the combined inverter output typically measures 30–40 kW ac. On a sunny day, design conditions of 200 kW ac have been reached. 54 HIGH PERFORMING BUILDINGS Spring 2008
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