Radiant by Joe Fiedrich RADIANT AUTHORITY Hydronic HVAC Made Real with Radiant his is a 2017 test site installa- For what I’m calling in this article enough sq footage of panel output is as this one. It keeps the overall sys- tion performed in a wood frame a “hydronic HVAC system,” the best available, an additional fan coil unit is tem cost in check, while performing Thouse (including garage, work- place to locate the tubing panels is an option.) both functions. shop and upstairs apartment) located There are any number of consider- in Carlisle, MA. The system has been in ations to keep in mind in a combina- operation for the past two winters and the best place to locate the tubing tion heating/cooling hydronic system summers under New England weather such as this one. conditions (which, for those who don’t panels is typically the walls and ceilings. A small buffer storage tank is defi- know, are hot and humid in the warm nitely recommended for overall months, cold and snowy in the cool typically the walls and ceilings. For a As a rule of thumb, try to cover the smooth system operation. ones). typical installation, the entire ceiling entire ceiling with panels to deliver Additional super quiet flat panel heating/cooling units can be added where needed for additional output and fast recovery on both heating and cooling functions. If a domestic hot water system needs to be integrated, the buffer tank needs more storage capacity with tank sizes of 37 or 70 gal. and a built-in heat exchanger (in this case a Chiltrix VCT or HCT Series) for pota- ble water. Otherwise a separate water heater is recommended, which will Chiltrix dew point controller. simplify the whole system design. In case the buffer tank is supplying DHW, a mixing valve needs to be installed between the buffer tank and the HVAC manifolds. A functional tub- Radiant Heating and Cooling R+D Building, Carlisle Ma. ing grid system is essential for equal heating and cooling water distribution in the ceiling and or Chiltrix fan coil unit for heating, cooling and dehumidification walls. Panels must be the proper square footage of radiation; easy to install over joists and studs and this is the key for system efficiency in existing sheet rock as well as concrete conjunction with heat pumps. The and concrete blocks to receive small more radiant surface the better, since it diameter tubing. will guarantee the lowest heating water Tubing spacing should not exceed temps as well as the highest chilled wa- 4.5", and circuit length not to exceed ter temps possible. 150 feet for 5/16" diameter ID tubing. After tubing insertion and before Small diameter oxygen Barrier PEX sheet rock or plaster board installa- tubing with small tubing spacing tion, aluminum foil was attached to and short circuits is essential and re- the grid panels via spray adhesive. duces both the dew point and con- Chiltrix air-to-water heat pump chiller.t This promotes the cooling radiant densation. The first step was to perform a com- should be covered with tubing pan- effect downwards. Conducting heat- Tubing must tidally snap into panel putation of the heating and cooling els and, if necessary some additional ing radiation downwards is a good grooves for secure mounting. load for the space. This particular home wall spaces. BTU output per panel (10 alternative to floors as well, which To keep material cost down, man- had all-fiberglass insulation, with walls sq. ft.) at a water temperature of 100°F makes the ceiling the best location ifold balancing valves can be elimi- and ceiling R19, roof R32. is approximately 120 BTU/hr. (If not for a combination panel system such ➤ Turn to Hydronic, page 38 32 • SEPTEMBER 2020 ➤ www.contractormag.com Best Practices Hydronic HVAC Made Real with Radiant ➤ Continued from page 32 nated by piping the manifold supply and return in “reverse return” fashion back to the circulator. However purg- ing system air during the initial fill be- comes a little more challenging. The supply and return between the Heat Pump Chiller can also be piped with PEX Barrier tubing. Copper or alu- minum PEX rigid pipe is an option. To prevent surface condensation, ad- ditional measures must be taken in geo- graphical areas of high humidity con- ditions, with RH of 60% and higher. In this application the heat pump chiller was equipped with an additional dew point controller to ramp up the water temperature during high humidity lev- els. In addition, we installed a Honey- well dehumidifier to keep the air at RH of 50% or lower. However, the CXI fan coil units we used can also be used as dehumidifiers. We never observed any ceiling sur- Upstairs plastered Blueboard Heating/Cooling Ceiling. (Inset) Radiant ceiling grid by Hydronics Mfg. Thermal images of the radiant cooled Get your own face condensation or wet equipment ceiling. (such as metal tubing, circulators or manifolds) even the extreme. Surface temps of the plasterboard was under outside conditions of 90% RH. 65°F, maintaining 72°F room temperature. In reverse Humidistat # H6062 A 1000 subscription today Under extreme outdoor temperatures of below for the heating mode we never observed water tem- • Circulators: Grundfos UPS 15-58FC3-speed per minus 20°F our supply water temperature never ex- peratures above 90°F. manifold ceeded 90°F. And at plus 95°F outdoor temperature These low water temperatures are essential for the • Distribution Manifolds: 1” Stainless Steel Plumbing, piping, mechanical, hydronic heating and fire Chilled water temp. of 48°F with a return of 57°F was heat pump’s efficiency, especially at outdoor condi- • Zone control: circulators controlled by Honey- tions under 32°F. A small, wall hung, electric boiler well thermostats. sprinkler contractors turn to Contractor Magazine for how-to can be piped in series with the heat pump. • Tubing suppliers: Uponor and Viega. HydroData Multimeter® Necessarily high and low operating water tempera- • Tubing distribution system: 5/16” PEX Tub- features, insight, industry exclusive reports and the latest tures are possible due to the large unobstructed ceil- ing with Oxygen Barrier 0-250 PSI Gage & Differential Pressures ing surface areas providing us with an ideal square • Tubing mounting grid system: Hydronics news, products, and technologies. Associated High Side & Low Side Pressures -67 to 260 °F Temperature foot area which allow water temps. almost approach- Mfg. UNI-Panels for Ceilings and Walls, ½”X32”X48” ing room temperature set points. with tubing spacing of 4.5” on center and snap in 100 Reading Memory with Sequential Recall grooves for secure tubing mounting. English & Metric, Auto-Read The typical Delta T between heating supply and Contractor’s mission is to help plumbing, hydronic and mechanical return is 10°F, and chilled water temp. return and • Antifreeze solution: 10-20% of heating sys- supply 10°F under design conditions. tem-rated polypropylene glycol. contracting business owners and managers run better businesses and help Zone control can easily be achieved by either circu- • Heating/Cooling transfer sheeting: 6 mil lator or manifold zone valves. aluminum foil them maintain, repair and install plumbing, heating, specialty piping and For additional information please check www.Hy- Equipment List dronicsmfg.com. For more info please email jfiedrich@ fire protection systems for residential and commercial, industrial and • Heating/cooling source: Chiltrix Air to Water hydronicsMFG.com. Hydronics Manufacturing is a Heat Pump Chiller CX34 : 3 Tons heating and 2 Tons supplier of the Uponor QuikTrak panel and the Viega institutional buildings throughout North America. Cooling Climate Panel system. Chiltrix (www.Chiltrix.com) • Control system: Chiltrix Psychrologix (check was the supplier of the heat pump chiller equipment out www.chiltrix.com for control sequence), Honey- for this project. well Humidistat and Thermostats SIGN UP TODAY AT: AvailableAvailable inin PrintPrint & DigitalDigital FormatsFormats • (Optional) High efficiency chiller fan coil Joe Fiedrich is a former hydronic heating columnist for Shortridge Instruments, Inc. units: CXI 120, 12,000 BTU cooling and 10,000 CONTRACTOR. He was the president of Stadler Corp., BTU heating which is now part of Viega North America, and he is the ContractorMag.com/NewSub 7855 E. Redfeld Road Scottsdale, AZ 85260 • Buffer Tank: 19 Gallon Stainless Steel by Chil- inventor of the Viega Climate Panel and Uponor Quik 480-991-6744 Fax: 480-443-1267 trix Trak. He is now President/CEO of Hydronics Manufac- www.shortridge.com • De-humidifier: Honeywell model # DR 65 with turing Inc. For information circle 218 38 • SEPTEMBER 2020 ➤ www.contractormag.com Available in print and digital formats. 2006CO_Shortridge_337577-0620.indd 1 5/6/20 12:34 PM 2007CO_House_NewSub.indd 1 6/11/20 9:41 AM.