Trial / Demo
IES recently joined forces with experts from Mazzetti and Arup for an exclusive webinar, exploring the challenges and opportunities involved in decarbonizing healthcare facilities, and how they are navigating these with the help of IESVE software.
In our latest blog, we delve into some of the questions raised during the Q&A portion of the session, and share some additional resources for those looking to dive deeper into this topic.
During dynamic simulation IESVE applies schedules to all internal loads. The user needs to define schedules and/or diversity factors to properly model the cooling and energy impacts of an MRI. When running room load sizing you should make sure that this gain is saturated to ensure that the local cooling load is captured in the peak.
In cases like this you need to double down on your research to find points of truth to allow you to bracket your unknowns. The NREL (now NLR) has produced documents supporting the modelling work that went into developing the ASHRAE Advanced Energy Design Guides for Healthcare which are a great resource.
Appendix A of ASHRAE 90.1 or the ASHRAE Construction Wizard in IESVE are great places to get estimated performance of building envelope systems based on assumed construction build-up. Once you’ve identified the range of performance that systems are likely to have you can bracket your results by running worst-case and best-case scenarios to better understand the range of unknown performance to give you more confidence in how much your results depend on these inputs. With existing buildings there is also often the opportunity to work with historical utility data to confirm if your modelling assumptions and methods are of the correct order of magnitude.
IESVE currently only allows the simulation of a single heat recovery chiller, however there are ways to work around this for larger plants. Chillers can be simulated as cooling only, water-source, central plant heat pumps to allow them to be connected to a common heat transfer loop for heat recovery. Alternatively, a custom chiller curve can be developed for the heat recovery chiller using the spreadsheet available for free in the IES Content Store to capture the performance of multiple heat recovery chillers in a single component.
This can be done via ApacheHVAC controls and schedules. Ventilation requirements can be set based on CFM, CFM/ft2, ACH, etc.
Healthcare facilities pose many design challenges due to their large facility size, complex systems, stringent health and safety standards, and the need to maintain 24/7 operations, amongst many others. However, these challenges also present some unique opportunities. Their large size can offer economies of scale, while 24/7 operations often yield shorter paybacks for capital investment. You can explore these challenges and opportunities in more detail in our Decarbonizing Healthcare guide.
As part of the session, Mazzetti and Arup shared key insights and lessons learned from UCSF Health’s Helen Diller Hospital, where the project team used IESVE to evaluate an all-electric central plant design. You can check out the full case study here, with further questions from the session answered below.
This project does not include a formal performance guarantee for Scope 1 emissions or energy savings. However, it adheres to the ASHRAE 90.1 2010 energy compliance pathway as well as LEED v4, with some credits aligned to v4.1. These standards helped to guide the design towards its efficiency and sustainability goals.
The team leveraged IESVE’s advanced capabilities to guide key design decisions, using detailed load analysis, HVAC modelling and parametric simulations to test multiple scenarios. Python scripting integrated real-world operational data for accurate assumptions, while CFD modelling validated the performance of the displacement ventilation system. This ensured decarbonization goals were met while staying within budget and reducing operational costs.
Customized load profiles were derived based on monitored data from the existing building in operation, helping to increase the accuracy of the calculations.
The displacement ventilation (DV) system is delivered through ductwork instead of a plenum. Therefore, any temperature gain in the supply path should be minimal. Even so, the project team conservatively assumed a 2°F temperature rise.
The design delivers 35% annual site energy savings, 23% energy cost savings, and 33% GHG reductions compared to the baseline. The local grid emission factors used for the analysis were 206.5 kg/MWh for electricity and 181.2 kg/MWh for natural gas.
It was determined that full electrification was not the right fit at this time, given the campus-wide central plant electrification effort already underway. As a result, the project elected to pursue a hybrid strategy, which proved to be the most cost-effective approach.
The campus has the overall renewable energy purchasing program, but there was no available roof or site area as part of this particular project for renewable energy deployment.
The design incorporated an electric sterilizer instead of a traditional natural gas (NG) based sterilizer.
This was a design-build project, with the contractor involved early to align design and construction goals. The DV system is a good example of how the energy model supported the decision to keep it in the project, rather than value-engineer it out.
Download your free copy of IES’s Decarbonizing Healthcare guide, catch the webinar on-demand or explore our webpage to find out more.
