1. Variable Frequency Drive (VFD)
HEATING, COOLING & WATER HEATING PRODUCTS
Variable Frequency Drive (VFD)

2. VFD – Product Offering
VFD units are identified by the letter “H” in the sixth character of the Model number (i.e. RKNL-H090CR15E).
VFD units drive package are identified with R,S or T in 11th character of Model number (i.e. RKNL-H090CR15E).
The 7 ½ through 25 ton models are two stage cooling with Variable Frequency Drive (VFD) and Clear Control.
7 ½ and 10 ton
15 to 25 ton

3. VFD – Competitive Landscape
ASHRAE and California Title 24
Each standard requires a minimum of two stage cooling operation above 110,000 btu.
Each standard requires a minimum of a two speed supply fan above 110,000 btu.
Best way to accomplish multi speed supply fan on 3 phase RTU is with VFD.
Rheem’s VFD will meet other major competitors:
Lennox MSAV (Multi-stage air volume)
Carrier SAV (Staged air volume)
Trane’s Multi-Speed Indoor Fan System

10. VFD – How It Works Clear Control VFD VFD located in control box
Mode
Compressor 1
Compressor 2
Fan
High Cool
Cool
High
Low Cool
Off
Low
Fan Only
High Heat
N/A
Low Heat
Clear Control
VFD located in control box
VFD operates at low speed on 1st stage cool and fan only.
Clear Control on all VFD models.
VFD

11. ( ) VFD – How it Works Low spd. power = High spd. Power or
Fan Laws
Power goes down eight times faster than air flow.
10 and 20 ton example, see graph.
Low spd. power = High spd. Power or 3
( )
Low spd. cfm
High spd. cfm

12. Points of Interest – Supply Fan VFD
Ventilation (fresh air) savings
Ventilation is required in commercial buildings.
Current RTU supply fresh air at a constant high speed
Wasteful; uses a lot of energy
VFD saves up to 85% over standard constant speed RTU’s by operating constant fan at 50% of high speed airflow.
Part Load Savings
Commercial buildings are designed for full load.
Full load only needed 10% to 30%.
70% to 90% of operation is on 1st stage cooling
VFD technology increases IEER by up to 51%.
Improved Comfort
Current RTU operates supply fan at 100% on 1st stage cooling.
VFD RTU operates supply fan at 50% on 1st stage cooling.
VFD technology removes twice as much moisture!

13. Commercial Prestige RTU– Sales Message
Replacement:
Today’s rooftop units are more than 30% more efficient than a rooftop that was installed 15 years ago. By replacing an old rooftop with Rheem’s Prestige Series™ rooftop, the building owner can save significantly on annual cooling cost.

14. Commercial Prestige RTU – Sales Message
New Construction:
When constructing a new building, purchasing a Package unit that has a higher efficiency rating then Minimum required – offers a quick payback on initial investment.

15. HEATING, COOLING & WATER HEATING PRODUCTS
HumidiDry™

16. HumidiDry
HumidiDry is Rheem’s exclusive dehumidification package unit solution.
HumidiDry controls temperature and humidity independently.
HumidiDry removes humidity from the conditioned space after cooling requirements have been met.
HumidiDry reduces the latent heat in the occupied space when there is no sensible load without overcooling or overheating the space.

17. HumidiDry – Product Offering
HumidiDry units are identified by the letter “G” in the sixth character of the Model number.
The 3 through 5 ton models are single stage cooling.
The 7 ½ through 25 ton models are two stage cooling and include a Variable Frequency Drive (VFD).
3 to 5 ton
7 ½ and 10 ton
15 to 25 ton

18. HumidiDry – Competitive Landscape
Allows participation in the hot gas reheat market
Includes schools, restaurants, health clubs, grocery stores, retail, institutional and many other commercial applications.
HumidiDry will meet or surpass other major competitors:
Lennox Humiditrol® hot gas reheat
Carrier MoistureMiser™ hot gas reheat
York MAGNADRY™ hot gas reheat
Trane hot gas reheat
Currently competitors do not have VFD standard.

19. HumidiDry – Sales Message
Comfort and Indoor Air Quality
Controls Temperature and Humidity Independently
Delivers dry neutral air, no overcooling or overheating
Help meet ASHRAE , ASHRAE 62.1 and Title 24

20. Sales Message-HumidiDry
Rheem’s exclusive Variable Frequency Drive (VFD)
Industry 1st
Standard on 7 ½ tons and up
Low speed in reheat mode, 1st
stage cooling and continuous fan
Meets AHRAE and
California Title 24
Saves energy
Improves performance (IEER)
Increases comfort (more latent removal)

29. HumidiDry - Technical
Indoor Relative Humidity Sensor
Required for reheat operation
Not included with the unit
RHC-ZNS4 room relative humidity sensor (used in thermostat application)
RHC-ZNS5 room temperature and relative humidity sensor (used in BAS application)
Available from Prostock Parts

30. HumidiDry – How It Works
Mode
Compressor 1
Compressor 2
Fan
Notes
High Cool
Cool
High
Operates with (Y2) call, Ignores (H1/H2)
High Reheat
Reheat
Operates with (Y1 & H2)
Low Reheat
Off
Low
Operates with (H1 only) or (H2 only)
Low Cool
Operates with (Y1) or (Y1 & H1), Factory set point
Notes Definitions: Y1
Single stage cooling operation Y2
Two stage cooling operation H1
Space is above humidity set point by more than 2% and less than or equal to 5%. H2
Space is above humidity set point by more than 5%.

31. HumidiDry – How It Works

32. Sequence of Operation
Rheem_Reheat VFD\start.html

33. Questions?
Thank You