Santa Fe Senior Village - Submetering & Operational Economics

San Diego, CA

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National Community Renaissance (National CORE), a developer/builder of affordable housing, based in Southern California, use IESVE software to address operational economics in their projects, using submetering within IESVE to identify how much and where their buildings use energy.

Key Facts

  • Project Type: Housing for the formerly homeless
  • No. of Units: 54 (51 studios, 2 one-bedrooms, 1 two-bedroom manager's unit)
  • Energy Features: All-electric, max-fit PV system (possibly ZNE depending on budget)
  • Primary Funding Source: Low Income Housing Tax Credits
  • Schedule: Construction starting January, 2023. Completion June, 2024

Ed Mazria and the team at Architecture 2030 were the first to point out that "Architects Pollute" (Metropolis, October, 2006) and soon after the American Institute of Architects recognized the responsibility resting on the shoulders of the profession to help solve the Climate Crisis.  The industry is making progress, and many design teams routinely rise to the challenge.  At the same time energy codes in many countries and U.S. States (like California) continue to evolve and push design teams towards higher energy efficiency and wider deployment of on-site renewables.

There is a generational challenge to architects to unlock their inner engineering skills, identify the opportunities offered within the boundaries of energy codes, and to identify new styles and typologies that celebrate both sustainability and design.   Even so, while the worsening impacts of Climate Change hit our news feeds each day, slow motion change and business as usual tendencies are the norm.   A different approach and an alternative perspective is needed in conversations with clients, one centered on economics and more specifically operational economics.  Questions to consider include: What are the long-term economic consequences of design decisions?  How do you measure?  What do you share?  How important is renewable energy?  Who pays for what?

All of these conversations are important for National Community Renaissance (National CORE), a Developer/Builder of affordable housing, based in Southern California but with footprint reaching to other regions and other States (currently Texas and Florida).   For them, first cost is important - their budgets are fixed - but equally important are the long-term operational costs for the buildings they are designing, developing, and building.

To address these challenges, National CORE build, test, and measure their assumptions in IESVE Software.  They use key features, in particular the ability to create sub-meters to isolate how much energy goes where, how much renewable energy their buildings can accommodate, and most critically, where the renewable energy gets allocated.  They prioritize getting common area electricity to zero first, then distribute excess energy to residential units, many times achieving Zero Net Energy.

Previous IESVE Case Studies have demonstrated National CORE's approach to conceptual energy analysis and right-sizing HVAC analysis.  The next step in their process is to identify how much and where the building will use energy. This data can then be used to identify how much it will cost to operate the building, with the approach also making it possible to determine the impact of onsite renewables.

Working within IESVE, as the building envelope is optimized and the HVAC zones are created and HVAC sizing is completed, National CORE focus on performance analytics in the VistaPro Application to determine energy use and operational costs. To achieve this, they have adopted the following workflow, which was recently applied to one of their current projects, Santa Fe Senior Village, a 54-unit complex located in San Diego, CA:

  1. For most of their projects, residents pay their own utility costs, so it's important for National CORE to identify common area energy use, so they can hit common area ZNE first.  For National CORE, ZNE is easily within grasp with large scale rooftop PV for buildings three stories and less.  When buildings hit four stories or taller (as many of theirs do), ZNE is harder to achieve (their four-story buildings offset approximately 60% of total energy with rooftop solar). Within Apache, they begin by defining electrical sub-meters for specific building uses isolating common area (i.e. common area lighting, common area HVAC, elevators, washers and electric dryers, common area plug loads, ventilation fans) from residential uses (residential HVAC, lighting, plug loads, cooking loads). As National CORE builds "all-electric" buildings, they do not have other fuel sources. However, it is possible the define other fuel sources (like natural gas) within the software too.
  2. Once the meters have been defined, an annual simulation is performed with APACHE. When testing different assumptions, National CORE are careful to give the APACHE simulation a unique descriptor, so they can study the impact of each design strategy within the VistaPro Application. 
  3. The VistaPro Application provides advanced analysis and insight into building specific data (energy, heating and cooling loads, ventilation analysis, etc). Once the APACHE analysis is complete, National CORE proceed to the VistaPro Application to find their simulation file. From here, they are able to view the energy breakdown and meters, identifying the electricity loads they would like to isolate and selecting the reporting method most appropriate to their analysis (table format, bar charts, line graphs). 
  4. IESVE has introduced robust utility tariff tools which help determine the costs to operate the building. Therefore, the next step for National CORE is to open up the "Tariff Tool" within the VistaPro Application to identify the utility company that will service the building. As National CORE has a large existing portfolio of operating projects, they can use similar buildings in the same utility service area to identify the probable utility schedule. They use the "Import Rates" button to open up a dialogue box to select the relevant utility, being sure to match the name of the utility as it shows on the "Utility List" button (which hyperlinks to a website with all U.S. utilities).
  5. Next, they "Select" and “Import” the appropriate utility rate. Santa Fe Senior Housing is a multi-family building, so it will use residential utility rates. Similar projects in San Diego Gas and Electric territory use the TOU-DR1 rate schedule, which was selected here.
  6. The final step is to run the calculation. IESVE uses the actual rates for the building to identify the cost to operate the building. When the analysis is complete, the "Annual Energy Costs" tab is selected to identify the total operating cost. For this, a 54-unit special needs project, National CORE were able to anticipate the annual energy cost (based on current rate schedules) to operate their building. The VistaPro Application allows a fully-costed APACHE-Post-Processed (.APP) to be visualized, including the seasonal cumulative Time-Of-Use charges and the total hourly electricity costs. 

Energy analytics, especially for affordable, multi-family housing, is a multi-step process, beginning with conceptual energy analysis, continuing into the HVAC system sizing analysis, then landing in analysis of costs to operate. For National CORE, cost analysis is the most critical step and is their starting point for conversations with the design team. For Santa Fe Senior Village (and other projects) they can use the analysis outputs from IESVE to drive discussions around what they can do to get their operating costs down, or how much PV they can land on the building and the site to minimize long-term operating costs. As a next step, they can run other iterations to improve energy performance and optimize renewable energy deployment. 

“The path to cost-contained, high performance affordable housing requires precision and, whenever possible, modeling efficiencies. NCORE relies on IESVE to help pin down critical analysis, providing detailed reports, paving the way for us towards zero net energy and carbon neutral projects. 

Santa Fe Senior Housing is an example of how we can achieve a high-performance, climate-conscious and affordable building design within a limited budget, now showing how we can get into and fine tune operational economics to unlock long-term savings. The less it costs to operate, the more we can invest in high performance energy systems up-front. 

National Community Renaissance continues to lead the affordable housing industry, telling the real-world story, showing what is possible in affordable housing. When it comes to high performance, zero net energy, and carbon neutral projects: If we can do this, everyone can.”

Tim Kohut, AIA, Director of Sustainable Design at National Community Renaissance

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