Hopefully so you don’t end up with something like this! Basic components of a water-water & combo geothermal heat pump system. Tips on proper installation of a hydronic geothermal system Limitations of a hydronic geothermal system Some design considerations of the system Piping options for the load side Control options for the hydronic system Design water temp won’t heat space. ◦ Insulation generally is the culprit Heat pump is locking out on HP. ◦ Waterflow, Waterflow, Waterflow! ◦ To much load side antifreeze? ◦ Controls, Controls, Controls! High bill complaints. ◦ Low loop temps, could be a multitude of reasons! ◦ Running system at max 120F temps all season. Design of the system must meet the expectations of the customer, and it is your job to install and verify your system will do the job! What will be my design max water temp? What will be my design min water temp? Will I have a supplemental or backup system? ◦ If so, how will it be piped and controlled? What is the heat distribution system? ◦ High mass floors - concrete ◦ Low mass floors – staple up ◦ Radiation – high or low temp Am I doing chilled water for cooling? Do I have areas that need antifreeze? Who is doing the insulation? What is it? What type of floor coverings do I have? Doing an accurate load calculation is priority number 1 including radiant design! This will dictate your supply water temp and flow rates of the system. Knowing the building materials, insulation values, floor coverings, etc. is critical. Jobsite verification of building materials and insulation practices (pictures, pictures) This all goes into a successful installation and a happy customer with low energy costs! Concrete slab with R-5 edge and horizontal. Concrete slab with R-10 edge and horizontal. Radiant floor tube spacing at 9” o.c. min. Do not mix more than 25% glycol antifreeze on load side of heat pump (preferably 0%) Flow rate through each radiant floor loop to be between .50gpm and .75gpm Pipe sizing is critical; flow = BTU’s Variable Speed pumps & zone valves! Insulation values, floor coverings, flow rates, tube sizes, etc. all factor in to calculating system design! • Energy obtained from or rejected to a ground-coupled source (closed-loop) • Utilized to make domestic hot water • Utilized for hot water hydronic systems • Utilized for chilled water hydronic systems • Optional desuperheaters • Energy obtained from or rejected to a groundcoupled source (closedloop) • Utilized for hydronic heating applications (no chilled water ) • Utilized to heat or cool air in forced air applications • Packaged system • Optional Desuperheater Source Side W2W Unit Load Side We are going to focus on the Load Side of the System! ALL heat pump hydronic systems require a buffer tank (well almost ALL). ◦ ◦ “Decouples” floor pumping and unit flow requirements. Usually 1 gallon per 1,000 Btuh In most cases, controls are the most difficult part of the installation. ◦ Know what you’re getting into! Design systems for max. water temps of 120F or less for compressor life and efficiency! V = T x (Qhp – Qload)/Delta T x 500 V = Volume T = Desired minimum run time (minutes) Qhp = HP Capacity Qload = Heat flow to load when HP is on Delta T = Differential set point (10F) Example = 5 x (52,000 - 0)/10 x 500 = 52 The capacity of the heat pump and depending on the control strategy will determine the amount of storage needed. Hot tank – single set point ◦ Usually 10 gallons/ton or 1gal/1000btu’s Demand controlled – single set point ◦ Usually 6 gallons/ton or 1gal/1500btu’s Combo units buffer should be smaller! Example = 5-ton (52MBH + hot tank) ◦ 5-tons x 10gal/ton = 50gal or 52,000btu/1000= 52gal Both Source Side and Load Side Coaxial heat exchangers are typically identical ◦ ◦ Pressure drop ratings are the same Flow rates on the load side should be roughly the same as the source side 2.5-3 gpm per ton Connection size doesn’t always mean pipe size (unit or pump flange) Hydronic radiant systems depend on supplemental heat source: ◦ No supplemental heat – up size loop ◦ Direct supplemental heat – same as W/A ◦ Indirect supplemental heat – up size loop Combo unit systems: ◦ 100% radiant – size as you normally would depending on supplemental heat source ◦ Some radiant & some F/A – up size loop Hydronic systems will need more loop based on the mass of the system vs. heating air! Ground Source Heat Pumps using R-410a refrigerant typically can only achieve a maximum load side temperature of 120F ELT. This prohibits the use of this technology with other forms or hydronic heating such as radiators and/or sometimes baseboard radiation. ◦ There are new low temp baseboard radiators available that will heat at lower than 120F! With the COP of the HP going up as the load water design temp goes down, outdoor reset makes sense as a recommended control strategy. Outdoor reset control will vary the design load temperature based on outdoor temperature. The colder the outside temp, the warmer the load temp. This maximizes the COP of the system. The Effect of Glycol on Microbial Activity % of samples found with > 1000 CFU/mL Probability of Contamination 100% 80% 60% 40% 20% 0% 0% to 10% 10% to 20% 20% to 25% above 25% Concentration of Glycol (vol%) Water quality is also very important!!! Pipe size Flow (gpm) Max P.D. (FT/100 FT) Max. Vel (FPS) 1/2" 0-2 5.0 2.2 3/4" 2-4 4.4 2.4 1" 4-8 4.8 3.0 11/4" 8-15 4.0 3.3 11/2" 15-24 4.0 3.7 2" 24-45 4.0 4.4 2-1/2" 45-72 4.0 5.0 3" 72-130 4.0 5.7 •Notes: Use with hot water and chilled water closed piping systems Based on schedule 40 BI or Copper pipe • Water-Water Unit Applications • Pressurized piping systems • Controls • Combo Unit Applications • Pressurized piping systems • Controls Water-Water Heat Pump ◦ Buffer Tank (Pressurized or HSS) ◦ Load Side Pump ◦ Controls (Aquastat) ◦ Air Pad ◦ Flow Center Pressurized Non-Pressurized Hose kit Tubing ◦ Fasteners ◦ Manifolds ◦ Fittings Zone pumps/Zone Valves ◦ Flanges (w/ pumps) Hydronic Accessories ◦ Air Eliminator ◦ Expansion Tank Controls ◦ Zone Control ◦ Pump Relay ◦ Thermostats Tubing Manifolds PT Ports Aqua-stat Load Side Pump Zone Pumps GW Unit Buffer Tank W2W Unit Aqua-stat Tubing Zone Pumps Load Side Pump Flow Center Buffer Tank Manifolds Sensor in tank 115F T1 24V AQUASTAT WITH N/O DRY CONTACTS THAT WILL CLOSE ON FALL IN TEMP! T2 HEATING ONLY CONTROLS! W2W Unit Aqua-stat Load Side Pump Buffer Tank Flow Center Combo Heat Pump ◦ ◦ ◦ ◦ ◦ ◦ ◦ Thermostat (Forced Air) Electric auxiliary heater (Optional) Air Pad Buffer Tank (Pressurized or HSS) Load Side Pump Aquastat (hydronic control) Flow Center Pressurized Non-Pressurized Hose kit Tubing ◦ Fasteners ◦ Manifolds ◦ Fittings Zone pumps/Zone Valves ◦ Flanges (w/ pumps) Hydronic Accessories ◦ Air Eliminator ◦ Expansion Tank Controls ◦ Zone Control ◦ Pump Relay ◦ Thermostats GT Unit Aqua-stat PT Ports Load Side Pump Buffer Tank On Demand Control Strategy! • Water-Water Unit Applications • Pressurized piping systems • HSS non-pressurized piping systems • Controls (heating & cooling) • • • • • HSS System (on demand) HBX Controls (either or, plus Outdoor Reset) Geo-Tech (Don Schuster) (Set point) Terra-Therm Hydronic Controller (Set point) Do it yourself (who knows) • Controls (Heating only) • • • • • • HSS HBX Tekmar Johnson Controls Honeywell Ranco W2W units have lower EER’s than Water-Air heat pumps Be careful of sensible cooling capacities of the air handler or water coils – do not size strictly based on tonnage All piping with chilled water needs to be insulated including pumps Buffer tank must be insulated and have an air seal to prevent condensation Advantage – one unit vs. two units HBX ECO-1000 Wiring Diagram (2stg) What is the boiler’s primary function: ◦ Back up source only ◦ Supplemental heat – same output temp ◦ Increase supply temp to provide additional btu’s to high load areas ◦ What source of energy is the backup boiler Gas Electric Wood Pool & spa heating Domestic water heating Snow melt Process water chilling Ice storage or Ice arena’s Waste heat recovery Simultaneously heating & cooling Design the system properly, not using Btu’s per sqft, but rather good design practices. Insulation is a huge factor along with thermal breaks, if you aren’t doing it, verify it is done right! Select the proper control strategy for the application, buy off the shelf vs. build your own so anyone can service and troubleshoot! Size your piping and pumps for proper flow. Select your piping strategy for the application as well as the supplemental heat source. Thank You!!!