Hydronic Engineering Italian Style

By Bob “Hot Rod” Rohr

I recently returned from a trip to the northern portion of Italy. We visited Brescia, Italy, a town known for its marble quarries and production as well as small arms manufacturing. Over the course of 3 days I had a chance to meet and chat with a great group of wholesalers, contractors, designers and engineers -- and visit a couple jobsites. Rex Gillespie of Caleffi North America and Roy Collver, a manufacturer’s rep from Calgary, Alberta, joined me as Sergio Casarino of Caleffi showed us around the facility.

I had the pleasure of meeting ingeniere (engineer) Mario Doninelli. Mario designs hydronic and solar assisted mechanical systems around the northern Italian Lake Country area.

Mario has the “large” warm, outgoing personality of Dan Holohan, the engineering and “imagineering” skills of John Sigenthaler and the knowingness of Gil Carlson. He also has the unique ability to present material at a contractor’s level of understanding, like Siggy does so well. If you can imagine all that rolled into one person you would know Mario. Also include a hairdo not unlike the early Beatles.

Early on, I assumed the language barrier would limit our exchange of information and ideas. My Italian is poor at best and Mario’s English nearly the same. 

However, as soon as Mario rolled out some of his impeccably drawn hydronic plans the communication exchange started to flow much more smoothly. Lines and hydronic symbols are a universal language among hydronicians. Boilers, heat exchangers and Grundfos pump model numbers began to make the systems come alive in my head.

The highlight of the trip was two jobsite visits. We were met by a few engineers from the photo-voltaic (PV) and control side. These fellows were the installing contractors, wholesaler, and manufacturers associated with the projects.

Both projects we visited included an active thermal solar component. The first apartment complex, about 2 years old, had roof mounted solar panels supplying both domestic hot water (SDHW) and contributing to the hydronic heating load. Unical Modulex modulating boilers, which look suspiciously similar to the Aerco we see in the U.S., were installed as backup to the solar. 

The various buildings that we had a chance to visit were all engineered to access solar as the DHW generator, then as a hydronic load source. A collection of motorized 3 way valves switch the solar to the various loads, storage tanks, and if needed, to a pair of outdoor hydronic unit heaters for load shedding. The control package was built by Siemens.

The designers and installers have one obstacle common with their U.S. counterparts: The apparent lack of coordination between the architect and the mechanical engineers. For instance, some creative exposed piping was installed in the underground parking area to connect the mechanical room to the solar array two stories up. However, I applaud the architects on these projects for designing large, well lighted space for all the mechanical equipment. The mechanical rooms were completely finished with windows and skylights and white painted walls. Space was not an issue in these mechanical rooms.

Mario works closely with AFIS the second largest plumbing and HVAC supplier in Northern Italy. He maintains a small office in the main branch of AFIS also located in Brescia.

Mario consults and writes for hydronic manufacturer Caleffi. Mario is the main man behind the numbers and designs seen in the Italian Idraulica magazine, published by Caleffi since 1991, and the U.S. version, Idronics. He collaborates with John Sigenthaler in bringing this great publication to the U.S. by way of Caleffi.

Mario proudly showed us a much worn copy of a design manual he authored years ago. Unbelievably similar to the early works of Gil Carlson in regards to primary secondary concepts, designs and formulas. Mario is the brains behind the hydro separators we see being widely accepted for use in today’s modern hydronic applications. He’s also responsible for the design and calculations for the Caleffi HydroLink and HydroSeparators.

The most interesting project we visited is a sustainable energy project being built to showcase active thermal solar and PV energy systems, as a part of the sustainable housing in Europe (SHE) grant.

An array of 48 panels supply DHW and radiant floor heat to the project. Concrete tunnels provide mechanical chases between the buildings. Uponor Ecoflex carries hot cold and hydronic supply to the various units. Caleffi satellite hydronic modules units provide a means to meter the hot, cold and hydronic flows to each apartment.

This project had a pair of Viessmann Vitocrossal 300 condensing boilers as back up to the solar. A Siemens control system was being used also. 10 KW of PV panels with grid tied inverters are also planned for the project.

I did not see as much installed solar, thermal or PV as we drove across the Italian countryside. I recall seeing much more in Germany when I visited the ISH show this spring. I have a feeling Italy will be implementing more as energy costs and availability drives alternate energy options. The pilot on my Delta flight announced that gasoline was about $6.11 per gallon as we landed in Milan!

I’d put Mario Doninelli on the top of my list as the ingeinere to design practical, cutting edge hydronic and or solar designs, were I to build in Italy. Which I would love to do. Or anywhere else his skills may reach.

Salute! Mario.