Date of Award

2024

Document Type

Thesis (Master's)

Department or Program

Engineering Sciences

First Advisor

Alexis Abramson

Second Advisor

Roger French

Abstract

Climate change and rising electricity demand have driven the need for energy efficiency in buildings. Single-family residential buildings present opportunities for improvement, but current strategies for identifying savings are labor and capital-intensive. Developing a residential version of a virtual energy audit tool offers a cheaper, non-intrusive alternative. This study used 25 all-electric homes in Florida to refine algorithms from the previously developed EDIFES code, originally designed for commercial buildings. The analysis utilized one year of 15-minute electricity consumption, area, stories, and location. These markers include heating and cooling type, setpoint set back, HVAC load, pool pump load, refrigeration load, and effective R-value.

The heating and cooling type marker uses linear or segmented models based on daily consumption and outdoor temperatures. The type of heating and cooling systems were correctly identified in all but one building. The setpoint set back marker was used to estimate HVAC load with an 11% mean error, with 80% of cases having errors <20%. Pool pump markers, designed for constant-speed pumps, detected their presence with 100% accuracy. Validation with submeters showed a 4.2% average error in pump load prediction. The refrigeration load marker identified cyclical loads, mainly from the compressor, with a 15% error. Effective R-value was calculated using consumption and temperature data. If R-values were below ASHRAE 90.2 standards, improvements were simulated to quantify savings.

Using the results of these markers, savings were identified for each building. A 1°C shift in setpoints resulted in a 10% average annual reduction in consumption. Shortening pump schedules to only five hours/day or replacing pumps with variable-speed models resulted in an average predicted reduction of 7% and 23% respectively. For refrigerators, expected savings from cleaning condenser coils or similar are minimal due to the small size of the refrigeration load. Surprisingly, few buildings had low R-values, indicating a need for further refinement of assumed parameters. The largest and most cost-effective savings came from pool pump replacements and setpoint set backs. Replacing pumps requires a modest investment but offers significant savings. Setpoint set backs involve no capital cost and provide immediate savings.

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