1. Radiant Floor Systems Coupled with Geothermal Heat Pumps By Brian Urlaub, Enertech Global

2. Hopefully so you don’t end up with something like this!
Why are you here?
Hopefully so you don’t end up with something like this!

7. What are we going to cover?
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

8. What have the problems been?
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!

9. Questions to ask yourself?
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?

10. Proper design starts with Loads!
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!

11. Insulation, Insulation, & Insulation

13. Floor Coverings & Design

14. Concrete slab with R-5 edge and horizontal.

15. Concrete slab with R-10 edge and horizontal.

17. Staple up tubing with no underneath insulation and carpet for floor covering.

18. Staple up tubing with R-10 underneath insulation and carpet for floor covering.

19. Staple up tubing w/ HE plates, with R-19 underneath insulation, and low R-value carpet & pad for floor covering.

20. Other Recommendations
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!

21. Water-to-Water Heat Pumps
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
Who do you see as fitting in these three categories? 21

22. Combination Heat Pump (Triple Function)
Energy obtained from or rejected to a ground-coupled source (closed-loop)
Utilized for hydronic heating applications (no chilled water )
Utilized to heat or cool air in forced air applications
Packaged system
Optional Desuperheater
Who do you see as fitting in these three categories? 22

23. Typical Water-Water System
Source Side
W2W Unit
Load Side
We are going to focus on the Load Side of the System!

24. Load-side “Guidelines”
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!

25. Buffer Tank Sizing 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, )/10 x 500 = 52

26. Buffer Tank Sizing
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

27. Load-side “Guidelines”
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)

28. Loop Field Sizing “Guidelines”
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!

29. GSHP Max Load Side Temp
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!

31. Design the GSHP system to utilize the lowest water temps possible for proper space heating and highest system efficiency! Things to consider: - Tube spacing/sizing - Flow rates - Insulation - Floor coverings

32. Outdoor reset controls
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.

33. Glycol on Load Side
Water quality is also very important!!!

34. Affects of Antifreeze in System

35. Pipe sizing guidelines
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
3.7
2"
24-45
2-1/2"
45-72
3"
72-130
5.7
Notes: Use with hot water and chilled water closed piping systems Based on schedule 40 BI or Copper pipe

36. Heating only Hydronic Systems
Water-Water Unit Applications
Pressurized piping systems
Controls
Combo Unit Applications

37. Components of a Water-Water System
Water-Water Heat Pump
Buffer Tank (Pressurized or HSS)
Load Side Pump
Controls (Aquastat)
Air Pad
Flow Center
Pressurized
Non-Pressurized
Hose kit

38. Additional Components of System
Tubing
Fasteners
Manifolds
Fittings
Zone pumps/Zone Valves
Flanges (w/ pumps)
Hydronic Accessories
Air Eliminator
Expansion Tank
Controls
Zone Control
Pump Relay
Thermostats

39. Heat Only – W2W Unit & HSS Tubing Manifolds PT Ports Aqua-stat
Load Side Pump
Zone Pumps
GW Unit
Buffer Tank

40. Heat Only – W2W Unit W2W Unit Aqua-stat Tubing Zone Pumps
Load Side Pump
Flow Center
Buffer Tank
Manifolds

41. Heat Only – W2W Unit

42. 24V AQUASTAT WITH N/O DRY CONTACTS THAT WILL CLOSE ON FALL IN TEMP!
Sensor in tank
T T2
HEATING ONLY CONTROLS!

44. Heat Only – W2W Unit w/ HSS

46. Heat Only – 2stg W2W Unit W2W Unit Aqua-stat Load Side Pump
Buffer Tank
Flow Center

47. Heat Only – 2stg W2W Unit

48. Heat Only – 2stg W2W Unit

49. Components of a Packaged Combo System
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

50. Additional Components of System
Tubing
Fasteners
Manifolds
Fittings
Zone pumps/Zone Valves
Flanges (w/ pumps)
Hydronic Accessories
Air Eliminator
Expansion Tank
Controls
Zone Control
Pump Relay
Thermostats

51. Heating Only - Combo Unit
GT Unit
Aqua-stat
PT Ports
Load Side Pump
Buffer Tank

52. Heating Only - Combo Unit

54. On Demand Control Strategy!

55. Hot/Chilled Water Hydronic Systems
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

57. Chilled Water vs. DX Cooling
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

58. Sensible vs. Total Cooling

59. Heating & Cooling Hydronic Systems

60. Basic 2 Aqua-stat Wiring setup

61. Heating & Cooling Hydronic Systems

62. HBX ECO-1000 Wiring Diagram

63. HBX ECO-1000 Wiring Diagram (2stg)

64. Htg & Clg W2W unit w/ HSS

65. Htg & Clg W2W unit w/ HSS

67. Geo-Tech (Don Schuster)

68. Do It Yourself – Good Luck!

69. Back up Boilers 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

70. W2W unit w/ Boiler - Supplemental

71. W2W unit w/ Boiler - High Temp

72. Other Applications Pool & spa heating Domestic water heating Snow melt
Process water chilling
Ice storage or Ice arena’s
Waste heat recovery
Simultaneously heating & cooling

73. So, the Keys to Success Are;
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.

74. Questions or Comments???
Thank You!!!