The Resource Efficient Electrification (REE) method of building decarbonization incorporates strategic capital planning, an integrated design process, and an incremental, network-oriented approach to deliver building heating, cooling, and ventilation which:
requires limited or no combustion,
enables carbon neutrality,
is highly efficient at low design temperatures and during extreme weather,
is highly resilient, demand conscious, and energy grid-interactive,
reduces thermal waste by capturing as many on-site or nearby thermal flows as possible, and
incorporates realistic and flexible implementation strategies by optimizing and scheduling low carbon retrofits phase-in.
Overcoming the Barriers
Too often, building electrification is simplified as replacing the existing fossil fuel burning equipment with the same capacity of air source heat pumps. This one-to-one equipment swap mindset won't deliver decarbonization in tall buildings in dense urban environment for multiple reasons. First, the additional electrical equipment will require costly electrical upgrades not only at the building, but also at the grid level to support the increased capacity. This potentially could create a grid peak in winter time due to our cold climate environment at the same time as CLCPA is transitioning the New York grid to renewable generation. Building emissions would reduce as a result of the grid transitioning but not significantly due to the increased load. Finally, it is often not physically or economically feasible to do the replacement due to roof/mechanical room space constraint and high construction cost. In addition to replacing the heating equipment, the existing thermal distribution system (hot water baseboards, steam radiators, forced-air system, etc...) will most likely have to be upgraded to be compatible with output temperature of today's heat pump technology, adding to the overall project cost. Cold climate tall building decarbonization requires a whole-systems approach to overcome these challenges.
Why Go Electric
Efficient heat pumps reduce CO2 in tall buildings. Electric resistance and inefficient heat pump operation may not today.
Decarbonization Roadmap
The figure below illustrates a conceptual framework for accomplishing these objectives and overcoming the barriers described in a previous pages. Specific measures and sequencing will be highly bespoke for a given building, but engineers and their owner clients can use this bucketed framework to place actionable projects in context of an overarching decarbonization roadmap:
Actions
Review
Disaggregate time-of-use profiles to identify heat waste and recovery opportunities and to right-size equipment.
Reduce
Repair, upgrade and refresh envelopes.
Optimize controls.
Reconfigure
Eliminate or reduce inefficient steam and forced air distribution.
Create thermal networks and enable heat recovery.
Lower supply temperatures to ranges of optimal heat pump performance. • Segregate and cascade supply temperatures based on end-use.
Recover
Simultaneous heating & cooling in different zones of building • Eliminate “free cooling” economizer modes
Exhaust heat recovery; absorbent air cleaning
Building wastewater heat recovery
Municipal wastewater heat recovery
Steam condensate
Refrigeration heat rejection.
Other opportunistic heat recovery and heat networking.
Store
Store rejected heat from daytime cooling, for overnight heating.
Store generated heat— centrally, distributed, or in the building’s thermal inertia.
Deploy advanced urban geothermal and other district thermal networking solutions.