Conference Agenda

Climate change is increasing the frequency and severity of heat wave events; however, thousands of existing stucco box or “dingbat” apartment buildings in Los Angeles do not provide passive cooling, and instead oftentimes exacerbate an occupant’s exposure to extreme heat. Given that air conditioning is both costly and vulnerable to power outages during extreme heat events, this study set out to determine whether passive cooling retrofit measures could provide safe temperatures during a heat wave event, without the use of mechanical cooling, when applied to a typical apartment building in Los Angeles. In this study, a typical dingbat apartment building was digitally modeled, and indoor air temperatures were measured over a simulated one-week heat wave event. A matrix of passive cooling mitigation measures was then applied to the apartment building, and the change in indoor air temperatures was compared against the baseline apartment building. The analysis showed that the combined use of phase change materials, window ventilation, insulation, and exterior shading (CP-10), reduced the peak indoor temperature of the apartment building by 13.4℃ (24.1℉). Additionally, the quantity of hours above a dry bulb temperature of 35℃ (95℉), measured to be 69% of the of the total heatwave hours in the baseline condition, and 6% of total heatwave hours in the (CP-10) combination condition. The results suggest that indoor temperatures can be reduced enough to consider passive cooling retrofit strategies in place of mechanical solutions for older apartment buildings in Los Angeles.

Heat recovery heat pumps, also known as heat recovery chillers, offer a promising approach to improving central plant efficiency by leveraging waste heat, but their operation requires careful control to optimize efficiency. The heat recovery heat pump system retrofitted to a plant to provide the main source heating hot water, often by leveraging a cooling load on the chilled water loop as a heat source. This requires integration with existing equipment systems and prioritization of equipment stages based on efficiency or other management goals. This unique characteristic presents an interesting equipment control problem, as concurrent, balanced loads are needed for stable equipment operation.

This paper presents an open-source Modelica toolkit for designing and analyzing plant equipment and their control sequences for various heat recovery chiller configurations in a central plant. The toolkit allows users to evaluate and compare control schema for their specific plant configurations and building loads.

A case study of a large commercial building in South San Francisco, California USA is used to co-develop and test the Modelica toolkit. Preliminary results are shared in this conference paper to demonstrate the capabilities of the toolkit. The project engineers determined that additional heat sources and sinks were necessary to balance the building loads to allow the heat pump to operate during more heating hours. This leads to more complicated controls sequences for the equipment, which can be tested in the Modelica toolkit before being implemented. This allows engineers to determine which sequences are best suited to achieve their project goals.

Plug loads are not regulated by most energy codes but they account for a significant portion of a building’s energy use. Whole-building energy models often use assumptions for plug load equipment density and operational schedules, but the basis for these assumptions is often outdated and does not reflect the significant improvements in equipment efficiency or the evolution of modern usage patterns.

This paper presents the analysis methodology for developing new values for plug load density and operational schedules based on current data sources and analyzes the energy consumption and code-compliance impacts of these updates. While the analysis was focused on California’s energy code, the methodology is not location-specific and could be applied to other jurisdictions.

Courthouses differ markedly from standard commercial buildings yet are not represented in the DOE Commercial Reference Building set. This work develops a scalable framework coupling parametric EnergyPlus modeling with life-cycle cost analysis (LCCA) to identify climate-specific, cost-effective retrofit and design strategies for the Judicial Council of California (JCC) courthouse portfolio. Starting from the Oak Ridge courthouse prototype, the team adapted models to California vintages and system typologies, automated simulation across 16 climate zones using the eppy Python library, and integrated cost parameters consistent with California Trial Court Facilities Standards. The workflow reveals how measure interactions and regional variation govern cost-optimized packages and portfolio-level EUI targets. The method is replicable for other public building portfolios, bridging detailed simulation with statewide capital-planning decisions.

This paper compares modeled and measured performance of a high-efficiency all-electric retrofit and addition to a single-family house in Los Angeles, California. Electricity consumption was measured over one year at the circuit level to compare performance for measures of annual consumption, load profile (with emphasis on summer peak demand and base load) and individual end uses. Measured performance was 25% lower on an annual basis and 28% lower during peak demand compared to the design result from energy code compliance software. Measured base load was found to be 58% lower. Analysis of individual energy end use categories identified significant positive and negative discrepancies in modeled/measured energy and provides insight into driving factors. Lessons learned are discussed to both improve knowledge of real-world performance of electrification retrofit efforts as well as to inform future compliance-based and performance-based modeling practices and assumptions.