Advantages of Designing High Performance Energy Recovery Into Building Infrastructure: Maximize Energy Savings!

Rudolf Zaengerle, Konvekta USA Inc.

High-Performance Energy Recovery Fundamentals:

High-performance runaround energy recovery systems with advanced control software are operating at efficiencies of net 70-90 percent (based on annual energy consumption for heating and cooling). It's critical that high-performance systems operate at optimum performance under varying operating parameters. With several variable input parameters, controlling and optimizing a system requires a numerical-simulation-based controller that allows variable amounts of heat transfer fluid to be circulated throughout the system. Multi-functional systems, with additional energy preservation measures, add yet another level of complexity to the controller function.

Maximizing Energy Savings throughout the Building Infrastructure:

Heating and cooling energy input in the outside air is typically the largest energy consumer in a lab building.

However, with VAV and high performance energy recovery, other energy consumers become more and more important and need be addressed, in particular in view of net-zero energy building goals. There are many different ways to integrate some of the additional energy consumers with the traditional outside/exhaust air energy recovery system with remarkable energy savings results. We will focus on the following options in detail:

  • Generate process cooling water in winter
  • Re-use steam condensate
  • Make condensing boilers actually condensing
  • Eliminate cooling towers (at least in winter)
  • Preheat domestic hot water

Buildings with these integrations will be discussed and actual energy savings are documented.

Learning Objectives

  • Name 4 pre-requisits for high-performance energy recovery.
  • What are 2 elements to 'multi-functional' energy recovery systems?
  • Identify 3 significant energy consumers in a building other than outside air conditioning and distribution.
  • Name 3 building infrastructure energy consumers that can benefit and be integrated in outside/exhaust air energy recovery.


Rudolf Zaengerle is the President of Konvekta's North American operation. He holds a Master of Mechanical Engineering degree and a PhD in Business Administration, both from the Swiss Federal Institute of Technology, Zurich. He has also studied at Harvard Business School. He was an Assistant Professor at the Swiss Federal Institute of Technology's Energy Sustainability & Urban Planning Institute before he relocated to the USA to manage Swiss technology businesses in North America.


Note: I2SL did not edit or revise abstract or biography text. Abstracts and biographies are displayed as submitted by the author(s).