Region IX Chapter 77

February Member Meeting: Advantages of Primary/Secondary Plumbing Design for Integrating Solar and Hydronic Heating in Residential and Small Commercial Systems

  • 16 Feb 2016
  • 11:30 AM - 1:00 PM
  • University Arena "The PIT" aka Wise Pies, 1414 University Blvd SE


Advantages of Primary/Secondary Plumbing Design for Integrating Solar and Hydronic Heating in Residential and Small Commercial Systems 

Bristol L. Stickney, BSME
SolarLogic, LLC, Santa Fe, NM

Joint meeting with AEE

Register at:

$20.00 ASHRAE Members
$25.00 Guests
$20.00 NMAEE Member
$0.00 NMAEE Meal Deal Membership

Sudexco will provide food services for the event. There is no need to pre-order you meal.


Solar heat connects most easily with hydronic heating systems because solar thermal panels provide hot fluid at temperatures that are compatible with common heat loads. However, in order to make the best use of the solar heat when it is available and minimize parasitic heat loss and pump (electric) power, a heating system design must treat all heat sources, loads and storage components as an integrated system. 

In a conventional system, a plumbing design based on primary and secondary loops allows heat to be transferred from the fuel-fired heat source to any load connected to the primary loop. This concept can be successfully extended to two primary loops connected through a heat exchanger for a system utilizing both solar and backup heat sources. The advantages are numerous, but can be summarized as the ability to move heat from any place in the system to any other place at any time. Even components that alternately function as both heat loads and heat sources can be easily controlled in this configuration.

This ‘dual primary loop’ concept has been used as a template in recent years to standardize the design and installation of complex solar/hydronic heating systems with good results.  Well over 100 systems in New Mexico and dozens in other states have been installed in recent years using this configuration. Design details taken from these systems will be presented, utilizing solar thermal panels, heat pumps, boilers, wood stoves and waste heat sources and delivering heat to radiant floors, DHW tanks, pools, baseboard radiators and fan coils. Performance data from remote monitoring and continuous automatic logging is also available to view. Existing installations range from small residences of 1000 – 3000 square feet up to small commercial sized buildings up to 25,000 square feet.

About the Speaker 

Bristol L. Stickney, BSME
SolarLogic, LLC, Santa Fe, NM

Mr. Bristol Stickney is the Chief Technical Officer of SolarLogic LLC in Santa Fe, NM. With over 35 years of experience in solar heating, Bristol Stickney is a well-known authority on solar hydronic heating systems.

Bristol worked with the New Mexico Solar Energy Association for over a decade as Staff Engineer, Director of Research, Associate Director, Treasurer and Vice Chairman of the Board. During his tenure at NMSEA, he developed unique control system concepts that simplify the design of solar heating systems while simultaneously optimized their effectiveness.  These innovations subsequently led to well over 100 of his designs implemented and installed by Cedar Mountain Solar in New Mexico.  It is Mr. Stickney’s knowledge, expertise and experience that have provided the theoretical and practical bases for SolarLogic’s SLASH-D and SLIC products. These streamline the standardized design and control of complex solar heating in buildings.

Prior to his work with Cedar Mountain Solar, Bristol was Chief Engineer of Coyne Solar Manufacturing Company for 5 years, where he designed and oversaw assembly of batch solar water heaters, many of which are still in use.  Bristol also worked as a Research Associate with Amory Lovins at the E-source office of the Rocky Mountain Institute.

Bristol Stickney has a B.S. in Mechanical Engineering from the University of Maine at Orono.  Bristol holds half a dozen patents in solar/hydronic heating and a patent on a DC hydronic heating control, called the “SETH System,” that reduces the electrical demand of a hydronic heating system by up to 80%.

Bristol currently writes a monthly column on “The 6 Principles of Good Solar Hydronic Heating System Design” which is published in national magazines such as Plumbing and Hydronic Contractor and Plumbing Engineer.  He also has had articles appearing in Solar Pro, Home Power, Radiant Living, and the ASHRAE Journal. 


Last revised: 08.23.2018
by: Stacey Chan

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