Radiant Energy Systems

Located in Bethesda, Md., the Seymour Krieger House is listed on the National Register of Historic Places, and was designed in the 1950s by internationally renowned modernist architect Marcel Breuer.

The house currently is owned by an architect, and he wanted to restore the mechanical system while keeping the architectural integrity of the structure intact. Originally heated by a radiant floor heating system, the original boiler was still in place and operational, but the wrought iron radiant piping has corroded and was leaking in multiple locations.

“We discussed multiple alternatives,” says Dan Foley, Foley Mechanical, Inc. “But in the end, the owner decided to go back with radiant floor heat.

The bluestone floor tiles were painstakingly numbered and removed.  The concrete overpour, along with the original wrought iron radiant tubing, was removed.

New REHAU PEX radiant tubing system was installed, and a new concrete slab was poured.  The flagstones were carefully placed back in exactly their original positions.

 

 

The entire mechanical system was updated by installing a new Triangle Tube Prestige boiler, HTP DHW tank, Viessmann solar heat and DHW system, Grundfos ALPHA pump, Caleffi hydro-separator, REHAU radiant tubing and manifold, and new Carrier high-efficiency AC system.

 

To allow for multiple zones, Foley and his team re-piped and re-controlled the radiant system.  The Viessmann solar system will contribute to space heat when the DHW load is satisfied.

 

“The clients were a joy to work for and appreciated the hard work done by my crew on this difficult and challenging project,” says Foley.

Wichita, Kan. — Viega announces its partnership with the Center for the Built Environment (CBE) at University of California, Berkeley. The association will enable CBE and Viega to work together in educating the industry on new and more efficient technologies for commercial integrated hydronics systems.

CBE is a place where industry leaders and internationally recognized researchers cooperate to produce substantial, holistic and far-sighted research on buildings.

Fred Bauman, P.E., a prominent scientist at CBE, is leading a research program on advanced integrated systems with a focus on radiant slab cooling, also known as thermally activated building systems (TABS). CBE recently accepted a $3 million grant over the next three years on radiant slab systems to research methods for optimizing radiant systems for energy efficiency and comfort. Research provides more performance data that allows for guidelines for design and controls.

Viega and CBE are collaborating to develop training sessions and use the research for innovative product advancements and design guidelines.

“We are honored to be associated with CBE,” said Mark Parent, director of product management, Viega. “There is a lack of industry knowledge when it comes to radiant heating and cooling. Our hope is to help educate the industry on newer and more efficient technologies when designing commercial integrated hydronics systems.”

Viega provides versatile radiant heating and cooling systems in the industry. Suitable for residential, commercial or industrial applications, Viega ProRadiant^™ heating and cooling solutions include ViegaPEX^™ Barrier tubing, Viega FostaPEX^® tubing, Viega PEX Press fittings, manifolds, controls, mixing stations, sensors, mats, panels, tracks and plates.

CBE’s mission is to improve the environmental quality and energy efficiency of buildings by providing timely, unbiased information on building technologies, design and operation techniques.

 

The first installment of the Hydronics CSI was won by Nathan White, Whites Plumbing & Heating, Kenai, AK. His well-thought, concise answer earned him a Lochinvar Jacket. Congratulations to Nathan. Please stay tuned for more Hydronics CSI opportunities.

The Flaw:

Nathan White’s response:

First  let’s use a Knight Mod con boiler for this application where we can take advantage of the low return water temp, modulation , outdoor rest features for a high efficiency package. But since it is a solution boiler here’s what needs changed. 1) need closely spaced tees (the ones in the picture are incorrect as you need min 10 pipe dia of straight pipe from each branch and a maximum of 4 pipe dia between the branches) or use my personal favorite a Caleffi Sep4 hydro separator to hydraulically decouple the two circulators, eliminate air, dirt and magnetic particles. 2)The solution boiler with its copper fin construction needs a Low temperature bypass valve in constant low temperature application. This valve would be placed before the suction side of the boiler pump which need to have a(3) integral check or a check valve on the discharge side of it. (4) if not using the Caleffi Sep4 then you will need a Y strainer as well on the return side of the boiler to protect the heat exchanger. (5) The air separator could be removed from the system if a Caleffi Sep4 was used. (6) A system sensor also needs to be hooked up when the solution is ran in a low temp application with the LBV. (7) lets put some valve in this design Paul for the poor guy that has to service it in the future doesn’t have to drain the world to replace a pump. So iso valves on both sides of each pump and ball valves with purge drains on the other lines as a bare minimum to make for easy filling and purging of the system. (8) The boiler pressure relief valve needs to be turned down toward the floor.

The Correction:

The Answer:

1) The closely spaced tee’s separating the boiler loop from the secondary loop do not isolate the differential pressure from the boiler pump. In short, the boiler pump was in series with the zone pump.

2) The boiler is a non-condensing boiler and the (typical) low-return water temperatures from the radiant floor heat would cause the boiler to condense. Sustained flue gas condensation would over-time cause the heat-exchanger in the boiler to fail and the vent could degrade and allow CO to fill the structure. The LTV (Low Temp Valve) will ensure the water temperature entering the boiler will be 140°F or higher.

3) The boiler will produce temperatures above that of low temperature radiant floor heat requirements. The use of a 3rd party mixing valve to provide outdoor reset will allow the proper mixing. (One of several methods of OD reset mixing)

Natick, Mass is located just 15 miles west of Boston. Settled in 1651, the old town’s history is vividly displayed through its infrastructure and architecture.

After 134 years, the Bacon Free Library is still just that — a red brick beacon to education and exploration. Not far away, the Eliot Church of Natick was founded as a church and meetinghouse in 1651, where native Praying Indians and white settlers would come together in worship.

The Station tree, a 500-year-old, black oak, was respectfully left standing over the centuries, marking the boundary between Natick and Needham, MA. The age of the town — and its regard for all things antiquated — can be seen in almost every element. Even its heating elements.

 

“Most of the homes in Natick are hydronic museums,” said Derek Nord. “Steam of every variety is still used, and is still comfortable. But when the old steam boilers fail, most homeowners look to hot water as a replacement.”

Nord is a one-man boiler band. His laser-like focus on all things hydronic, paired with meticulous attention to detail, have kept him busy since starting Nord Plumbing & Heating in 2010.

Collaboration

“I love boilers,” he continued. “Hydronics and plumbing are all that I do. I know some really great guys if I encounter a job that needs AC or ductwork.” And those guys often return the favor when they need a boiler mastermind. According to Nord, he’s friends with a number of other tradesmen in town. They collaborate on projects if need be – even to the point of handing their calls off to each other when they’re on vacation.

With real estate at a premium around Boston, many homeowners in Natick improve and add onto existing homes instead of relocating. A recent remodel of Nord’s own 75-year-old Cape Colonial required the kind of collaboration Nord is used to.

The 1,400-square-foot home used steam heat and lacked any sort of air conditioning when he and his wife purchased it. The downstairs was gutted, and the existing porch was closed in to create a master bedroom, adding about 300 square feet.

Nord not only did his own mechanical work, but also opted to do the framing for the project himself. After carefully considering what it was he wanted to accomplish, Nord had the heating system mapped out, and called a friend for help with the AC.

“Given the lack of space, we decided against a regular ducted system,” said Nord. “We didn’t like the idea of evaporators hanging on the walls, so we chose a SpacePak high-velocity AC system over mini-splits.”

Small, but not simple

The job resembles Nord’s company and capabilities well; small, but by no means simple.

One of the complaints about the original system was that it was hard to control during the wild temperature swings that New England can experience. Nord wanted to make sure they were curbing expense while also optimizing comfort.

 

In the basement, Nord tore apart and removed the old 80,000 BTU steam boiler. Much to his surprise the unit was undersized. He hung several pieces of diamond plate aluminum and a 95 percent efficient, 105 MBH Burnham Alpine condensing boiler on a nearby wall, to be joined shortly by a number of other hi-tech, high efficiency products.

The boiler would eventually supply heat to four zones; upstairs fin-tube baseboard, downstairs radiant in-floor tubing, European-style panel radiation in the master bedroom and a 60-gallon indirect tank for DHW. Directly under the Alpine, Nord used a low-loss header, or hydro separator, to create a secondary loop from which all connected load draws. This allows for numerous zones to pull from the boiler at different flow rates simultaneously. It also adds a little extra water volume to the system.

“Controlled by the boiler’s outdoor reset, hi-temp water is supplied to a secondary loop,” explained Nord. “Via injection pumping, the hi-temp loop feeds fin-tube radiation upstairs, a single, six-foot long, three-panel Runtal panel in the well-insulated master addition, and the water heater.”

The primary loop uses a three-speed Taco 00R circulator, while each zone operates off its own Grundfos circulator. There is an extra circulator and set of closely-spaced tees installed but capped off for future use in the basement.

 

The secondary loop also supplies hi-temp water to a Viega hydronic mixing block, which selects a supply temperature for the five in-floor radiant loops based on its own ODR sensor. Very often, this runs between 100 – 115°F.

Careful selection

“Any time you’re putting together an intricate system like this, regardless of size, you really need to select components based on their individual performance as well as their ability to mesh well with each other,” said Nord. “Overall system performance can be tricky to perfect, but it’s a beautiful thing!”

Nord says he selected the Alpine boiler based on a number of factors, the first of which is that he simply doesn’t get any callbacks when he installs them. He initially switched to the Alpine because he wanted a stainless steel heat exchanger instead of aluminum. Since then, he’s found that the broad size range – from 80 to 399 MBH – means that the unit fits just about application he’s come across.

“The Alpine is very easy to install, and readily available through The Portland Group,” said Nord. “I use it on most of my hot water jobs.”

With the exception of the master bedroom, the downstairs is heated by Uponor 5/16 PEX in Quik Trak subfloor paneling under quarter-sawn oak flooring.

Last winter, Nord saw a roughly 40 percent savings on energy, despite the added living space and much improved comfort. “It’s not unheard-of for one of these oil-to-Alpine jobs to save upwards of 75 percent,” said Nord. “A few years ago I had a family tell me they were spending $800 per month on oil during the coldest part of the season. After the retrofit the following year, they were spending roughly $200 to $250 for gas each month.

Space at a premium

The job progressed slowly but deliberately. When the walls were torn out, they installed supply lines to the upstairs radiators and roughed in the high-velocity AC. Radiant tubing went down at a different time, and the bedroom panel radiator was installed late in the game.

“One of the biggest challenges was running supply and return lines through the basement,” said Nord. “The old, load-bearing posts and beams in the basement were tough to work around.”

But it’s Nord’s ability to work hydronic magic in historic homes that makes him a real asset to his community, whether that includes optimizing antiquated systems or installing cutting edge equipment in turn-of-the-century structures.

Date started: August, 2012

Date Finished: May, 2014

Size of Project: 1,400 square-feet

Workers onsite: 2

Boiler — Burnham Alpine condensing boiler, 105k BTU input

Mixing Block — Viega

Panel radiator — Runtal

Fin-tube radiation — Slant/Fin

Pumps — Taco primary, Grundfos secondary

Relays — Taco

Manifolds — Uponor 5-loop EP radiant heat manifold

Piping — Uponor 5/16 PEX

Radiant panels– Uponor Quik Trak

Tools Used — Viega ProPress

Valves — Watts and Webstone ball valves

Separators — Taco vent on primary, Spirotherm on secondary loop

Air conditioning — SpacePak high-velocity system