2. Natural Gas boilers: 20th century marvel

Workshop Date:


Generation redesigned: Increase plant efficiency and rethink heat generation. Discussion topics will include condensing boilers, heat recovery chillers, heat pumps, CO2 water heating, strategies to optimize the plant operation, solar thermal hot water, and waste to energy.



Panel Discussion 5x3
(3 minute presentations on various technologies)

  • - Heat recovery chillers – Jim Crabb
  • - Electrical system design and additional loads - Walt Vernon
  • - Geothermal heat pumps - Mark Stavig 
  • - Solar Thermal systems – Dr. Monika Weiss, ErgSol 
  • - Thermal storage – Reyad Sawafta, Phase Change Solutions 

Interactive breakout sessions

Regroup summary

Continued discussion on Decarb Community

Upcoming Workshops



  • Identify logic and methodology of plant design, looking at a 30-40 year equipment lifespan
  • Answer the question: How might we avoid locking in carbon-producing technologies like natural gas-fired boilers?
  • Learn intricacies of more efficient and alternatives to natural gas boilers. Examples: solar thermal, heat pumps, heat recovery chillers
  • Identify opportunities to ensure low/no-carbon technologies might be used for these long term investments
  • Explore utility implications (overall natural gas utilities, electric utilities - impact on utility providers and rate structures) and incentives for switching strategies.


Current State

  • Traditional central plant design in the US has always relied on natural gas-fired boilers to generate hot water or steam. We can't decarbonize if we burn fossil fuels. 
  • There's already a great deal of heat in our buildings - all the energy we put into lights, equipment, plug loads, etc. is heat that we are just throwing away - via cooling towers or economizers. This heat is available to be stored and reused.


  • Many designers are beginning to explore alternative, non-fossil fuel heat generation methods.
  • Heat pumps, heat recovery chillers, geothermal heat pumps, and solar thermal systems can all be effective methods of carbon-free heat generation.
  • Some states, such as Washington, are now requiring heat recovery chillers in all-new hospital construction.
  • Geothermal heat pumps use the ground as thermal storage on a seasonal scale.
  • Solar thermal systems collect 4 times the energy of photovoltaics, making better use of available roof area than PV.
  • Thermal storage with customizable phase change materials can be used to extend the range of renewable energy.

Call to Action

  • Eliminating combustion may require a range of technologies and new system design. Join the conversation to help us all navigate the barriers, such as perceptions of added maintenance, first cost, and messaging.
  • The design community needs to bring new ideas to the team and to the clients building new hospitals.
  • Many of the solutions for eliminating combustion are easily applied to new buildings, but much more challenging to integrate into existing hospitals. How can we help existing hospitals reduce their dependence on carbon?