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Vornado: Case Study
- Insight from the energy model:
- The calibrated energy model revealed that while the renovations to the building will yield significant energy and carbon reductions, the energy consumption from tenant spaces must also be significantly reduced to further drive down the carbon intensity of the building (and reduce/eliminate exposure to LL97 through the 2030 compliance period).
- While every effort has been made to ensure that the model reflects the design team’s best understanding of the building design and future usage, the modeled energy consumption, energy cost and carbon emission estimates will likely vary from the actual energy, cost, and carbon of the building after construction due to variables such as weather, occupancy, building operation and maintenance, changes in energy rates, changes in carbon emission coefficients, and energy uses not covered by the current modeling scope.
- In the first iteration of the decarbonization strategy, the team approached the project with an all-or-nothing electrification mindset. We found that the strategies that achieve the deepest levels of decarbonization and fully eliminate district steam and co-gen waste heat as heating sources may not be practical or cost efficient enough to be implemented in such a complex existing building. So we went back to the drawing board.
- In the second iteration of the project, a more holistic strategy emphasizing the following core principles was developed:
- Re-use existing infrastructure (i.e., piping and ductwork) where possible
- Electrify heating loads affordably
- Reduce space requirements for electrification equipment/systems
- Use thermal storage to shift & smooth loads to promote grid flexibility
- Resource Efficient Electrification framework: With these guiding principles, the Vornado team developed a new strategy that follows the Resource Efficient Electrification framework, which JB&B refers to as "Reduce, Recycle, Electrify". Phasing, cost compression, and space compression were prioritized so that measures are more likely to be installed and scaled to other Vornado properties.
- Invest in a Calibrated Energy Model – In large and complex buildings, building owners should invest in a decarbonization study with a highly accurate calibrated energy model. Accuracy in the energy analysis really matters and not all energy models are created equal. A decarbonization model should represent the building very closely so that studied strategies and measures have realistic energy and carbon reduction projections.
- Just Because It’s Feasible Doesn’t Mean It’s Practical - Anything is possible in an energy model. Technical teams must be aware that building ownership teams care about more than just the energy and carbon results from the model. Strategies must be practical in a real-world sense and should aim to re-use existing infrastructure where possible, minimize disruption, use space efficiently, and compress costs as much as possible. Technical teams must be prepared to show building owners how a particular measure will be installed in a way that makes sense
- Don’t Expect 5–7 Year Paybacks on Decarbonization Measures - Deep decarbonization measures will likely have long paybacks. This is due to a combination of high upfront costs of electrification technology, electricity prices that are 5 to 6 times more expensive than natural gas, and an inability to capture the true value of decarbonization investments. Ownership teams will have to adjust their payback expectations when considering deep decarbonization measures.
- Technological Innovation Isn’t the Only Innovation - There is a lot of new and exciting technology out there that could someday revolutionize the way we electrify buildings, but in the meantime, there are innovative approaches to electrifying buildings today with technology that is currently available. Purposeful dispatch of thermal energy sources and optimization for scalability, practicality and affordability are innovative strategies in their own right.
- Condition Leaving Exhaust Air - Recycling waste heat from exhaust air streams isn't a new idea...but using the refrigeration cycle to extract and lift heat from exhaust air streams to serve heating loads is a new and innovative concept. Essentially by air conditioning the exhaust air, heat can be recovered and lifted to higher temperatures by a heat pump to offset heating loads. The reverse is also true in the summertime, where exhaust air can serve as a heat rejection medium for the chilled water production of cooling loads.
- Low Temperature Hot Water in Existing Chilled Water Coils - Low temperature hot water enables heat recovery and air source heat pumps to have a big impact but reconfiguring all comfort heating systems in existing buildings to be low temp is difficult and costly. A more practical approach is to do the following:
- Electrify high temp hot water systems (i.e., perimeter systems) with water-source heat pumps and condenser heat recovery. Existing distribution infrastructure can stay in place.
- Transition AHU steam or hot water coils to low temperature, which can be served by air-souce heat pumps. The cost and scope of coil replacements is much more manageable than replacing all heating systems with low temp hot water infrastructure. In some cases, existing chilled water coils can be used with the low temp hot water and becoming a modified change-over coil where coil replacement is no longer necessary.
- Operations team adoption: These ideas are new and complex. Existing operations team must be part of the design and implementation of these systems and training is of critical importance. A system that is designed to be low-carbon will not be successful if it is not operated per the design intent.
- Disruption and phasing: Some of the best decarbonization strategies are also some of the most disruptive. Additionally, phasing must be based upon a number of factors including the rate of grid decarbonization, leasing turnover cycles and capital planning cycles.