1. HVAC & WATER Application note
Imola – June,

2. HVAC & WATER
HVAC
Heating, Ventilation and Air-Conditioning (HVAC) is all about efficiency:
Room temperatures need to be maintained at optimum levels to achieve the best occupant confort.
It is essential to consider how hit targets in reducing costs and carbon dioxide (CO2) levels.

3. HVAC & WATER
WATER - PUMP
An operating pump will normally consume more power than the hydraulic circuit requires and it is usually positioned in unconfortable site:
It is essential to consider how achieve targets in reducing power consumption, costs and CO2 levels.
Maintenance time and costs need to be reduced in order to avoid long plant standstill.
Pumps are used in many applications. They are commonly used for water supply, water treatment and pressure boosting in buildings, also for cooling water and general service water industry.
E.g.:
- Fire fighting
Irrigation
Pumping from shallow boreholes (using an ejector)
Small pumps can be used for fountains or swimming pools
In Italia**
Le pompe e i ventilatori sotto i 90 kW sono oltre 2 milioni di cui oggi solo l’8% regolati da inverter
Gli inverter sono tecnicamente ed economicamente applicabili ad almeno un ulteriore 52%
** Studi Save “ VSDs for Electric Motor system” e “ Improving the penetraetion of EEM and Drives”

4. Most of the time they have excess capacity
HVAC & WATER - Why VFD flow control?
HVAC & WATER systems are designed to operate under the most extreme conditions and, HVAC typically, in the “worst case” situations that the system will encounter
Most of the time they have excess capacity

5. Problems of traditional flow control
HVAC & WATER - Why VFD flow control?
Problems of traditional flow control
Low system efficiency
Difficult in regulation
Electromechanical stress
Noise due to mechanical resonance
High starting current
Big supply cable section or cable number
Maintenance cost and time

6. HVAC & WATER - Why VFD flow control?
Reducing the capacity of the systems when full capacity is not required provides significant energy savings without sacrificing system performance
VFD Flow control

7. Secondary Hot/Chilled Water Pumps
HVAC & WATER
Return Fan
Supply Fan
Primary cold/Chilled
Water Pumps
Condensor
Water Pump
Cooling Tower Fans
Secondary Hot/Chilled Water Pumps
The variable torque applications shown here can provide significant energy savings when they are controlled by adjustable frequency drives.

8. Pump Curve Operating Point System Curve HVAC & WATER - Characteristic
Details of the way that drives are interfaced with the building’s HVAC system have a major impact on the amount of energy that can be saved. In some cases, the simple relocation of a sensor or the changing of a setpoint can be critical to achieving maximum energy savings. This portion of the presentation considers factors that are critical to maximizing energy savings. While this example deals specifically with a pumping system, the same concepts apply to fan systems.
The Pump Curve determines the relationship between the flow and pressure that the pump can produce. The Control Curve determines the same relationship for the controlled system. Where these two curves intersect determines the pressure and flow that will result.
Q is proportional to the pump rotational speed
H is proportional to the square speed
Power is proportional to the cubic speed

9. P Power  Flow x Pressure WASTED Power New Power required Pressure
HVAC & WATER - Traditional throttling flow control P
New Power
required
WASTED Power
Pressure
drop
Power 
Flow x
Pressure
Power
to load
It helps to be able to visualize the amount of power that is associated with any particular combination of pressure and flow. Since power is proportional to the product of pressure and flow, the area of the rectangle that is formed between the axes of the pressure-flow graph and the operating point represents the power that is associated with the flow.
It should be noted here that this describes the power associated with the flow from the pump. It does not take into account the inefficiency of the pump, the motor, or any other portion of the system. While consideration of these inefficiencies will be important for a precise analysis of the total power requirements of the system, these do not need to be considered for this discussion.
Since the system will seldom need to operate at its full design flow, it is important to consider how to reduce the flow to the level that will be required under less severe conditions.
The traditional method of reducing the flow from a pump is to close a throttling valve. This increases the pressure that the pump needs to produce. The operating point is said to “ride up” the Pump Curve.
An examination of this situation shows that the power associated with this flow, as shown by the area of the purple rectangle, has decreased. However, only the bottom portion of this rectangle represents the flow and pressure delivered to the load. The rest of the rectangle represents power that is lost through the pressure drop across the partially-closed valve.

10. VFD avoids the pressure drop by controlling the speed of the pump
HVAC & WATER - VFD flow control
Cooling
Coil
Primary
Chilled Water
Pump
Secondary
Chill Water
Differential
Pressure
Sensor
Chilled
Water
Pump Drive
Chiller
Air
Duct
An adjustable frequency drive avoids this large pressure drop by controlling the speed of the pump. While there are a number of different ways of accomplishing this, the simplest and most common is to measure the differential pressure across the most distant significant load. A setpoint controller is used to adjust the speed of the drive to maintain the required system differential pressure. The concept here is that, if the required pressure is maintained here, sufficient pressure will be available throughout the system.
As the valves in the system are closed due to a reduced demand for flow, the pressure in the system will tend to increase. The differential pressure sensor will indicate this and the setpoint controller will slow down the drive to maintain the desired pressure.
The opposite happens when the demand increases.
VFD avoids the pressure drop
by controlling the speed
of the pump

11. P «Throttle control» Power required «VFD c.» Power required
HVAC & WATER - VFD flow control
«Throttle
control» Power
required
«VFD c.» Power
required
Instead of following the Pump Curve for a fixed speed, the operation of the system follows the Control Curve. As the required flow decreases, both the pressure and the flow decrease. As a result, the reduction in power is significant.
If the setpoint pressure was zero, the pressure would be proportional to the square of the flow. As a result, since power is proportional to pressure times flow, the power would be proportional to flow cubed. This is the familiar centrifugal fan or pump affinity law. When projecting the energy savings possible by using an adjustable frequency drive, it is important to remember that this only applies when the setpoint pressure for the Control Curve is zero. It is also important to remember to consider the efficiencies of the various devices in the system. P

12. Proportional Integral Derivative function (PID)
HVAC & WATER - VFD flow control
Proportional Integral Derivative function (PID)
The sum of these three actions is used to adjust the process via a control element such as the position of a control valve or the power supply of a heating element.
PID controllers attempts to correct the error between a measured process variable and a desired set-point by calculation and then outputting a corrective action that can adjust the process accordingly.

13. HVAC & WATER - VFD flow control
The target value or Set-point has to be set by user. This could be the desired pressure, flow, temperature, vacuum, etc.
E.g.: this reference is the measure of how much fluid is required to be sent to the wastewater pipeline.
Feedback value
Set point
Motor & Pump
VSD
Transducer
Pump outlet
Controller
Detector
Feedback value
Controlled Variable
Actuating Signal
Motor freq.
Comparator Σ
System
Set point
0-10VDC or 4-20mA signal

14. High degree of protection against dust and water sprays
HVAC & WATER - VFD flow control
The standard «ready-to-install» IP54 SINUS PENTA solution is particularly suited to HVAC & WATER applications:
High degree of protection against dust and water sprays
Ability to mount without additional enclosures and ventilation
PID functions for automatic control
Built-in EMC filter
Onboard communications allows control and monitoring

15. Extensive I/O with internal comparator functions
HVAC & WATER - VFD flow control
The standard «ready-to-install» IP54 SINUS PENTA solution is particularly suited to HVAC & WATER applications:
Extensive I/O with internal comparator functions
Fire Mode function for extended operation in critical periods
Speed Search function to start on a rotating load
Real Time Clock (RTC) function to adjust confort to demands that change over the week
Multipump function
Robustness and reliability

16. HVAC - SINUS PENTA advantages
AIR HANDLER
Reduce energy costs and CO2 emissions Variable torque load characteristics use less energy as speed is reduced
Reduce supply demand Drives reduce motor starting current up to 10 times
Reduce noise in buildings Airflow noise decreases by eliminating starts/stops and optimising flow rates
Reduce shock and vibration Drive avoids running at speed near system resonant frequency and provides controlled acceleration
Increased life of motor belts Drives provide low torque starts reducing stress on belts, pulleys and keys

17. WATER CONDENSER CHILLER
HVAC - SINUS PENTA advantages
WATER CONDENSER CHILLER
Reduce energy consumption Provide improved efficiency and reduce energy requirements
Reduce CO2 emissions Due to the energy savings
Provide continuous operation Restart a spinning motor after momentary power loss

18. Reduce CO2 emissions Due to the reduce energy consumption
HVAC - SINUS PENTA advantages
COOLING TOWER FAN
Energy savings and reduce energy costs Motor use less energy as speed is reduced
Reduce CO2 emissions Due to the reduce energy consumption
Reduce maintenance requirements and reduce operating costs Robust constructions and energy efficient

19. Wide power range for different pump sizes
WATER - SINUS PENTA advantages
PUMP
Reduce energy costs and CO2 emissions Variable torque load characteristics use less energy as speed is reduced
Reduce demand charges Drives reduce motor starting current up to 10 times
Control of pressure of flow using PID The drive can optimize the pressure flow, and its linearity variations, with a single pressure transducer
Wide power range for different pump sizes
Network communications Support all major protocols
Prevention of water hammer, pipe stress, valve, pump seals and cavitation Extends the life of the entire system

20. WATER - MULTIPUMP application overview
Controls a multi-pump pumping system (up to 5 pumps)
One pump is the speed-controlled master and the other pumps are variable speed or fixed speed slaves
Multi-Master mode
Connection using I/O or Modbus
Automatic balancing of operating hours of all pump sets
Elimination of water hammer

21. WATER - MULTIPUMP: Fixed Speed Slaves (FSS)
The Master pump operates to ensure the system fine-tuning. The slave pumps are started up/stopped based on the criteria below:
Percentage of the working power required for the master pump (allowing optimum performance of the plant).
Maximum allowable adjusting error.
Maximum difference among the working time of each available pump.
The power ratio of the connected pumps must meet one of the following requirements:
All pumps must have the same power ratings.
The connected pumps can have different power ratings, provided that each pump with the greatest power rating is matched with lower-rated pumps that, if combined, have power ratings equal to or higher than the former pump.
The power rating of the master pump must be higher than/equal to the power rating of the lower-rated pump.

22. PENTA MULTIPUMP SOFTWARE
WATER - MULTIPUMP: Fixed Speed Slaves (FSS)
PENTA MULTIPUMP SOFTWARE
Soft-Starter ASAB
Basic diagram for a fixed-speed plant including 4 slave devices and 1 MP Penta drive controlling the system in analog mode.

23. WATER - MULTIPUMP: Fixed Speed Slaves (FSS)

24. WATER - MULTIPUMP: Fixed Speed Slaves (FSS)

25. WATER - MULTIPUMP: Fixed Speed Slaves (FSS)

26. WATER - MULTIPUMP: Variable Speed Slaves (VSS)
The slave pumps and the master pump are started/stopped based on the following criteria:
Percentage of the working power required for the master pump (allowing optimum performance of the plant).
Maximum allowable adjusting error.
Maximum difference among the working time of each available pump.
All the connected pumps must have the same power ratings.

27. PENTA MULTIPUMP SOFTWARE
WATER - MULTIPUMP: Variable Speed Slaves (VSS)
PENTA MULTIPUMP SOFTWARE
Modbus MASTER
MODBUS RTU
Modbus SLAVE
MULTIMASTER
FUNCTION
PENTA DRIVE
PENTA DRIVE
The diagram above shows a configuration for a variable-speed multipump system, serial communications and Multimaster function.

28. WATER - MULTIPUMP: Variable Speed Slaves (VSS)

29. HVAC & WATER: Variable Air Volume (VAV) Supply Fan
Heating
Coil
Cooling
Relief
Air Damper
Outside
Return
Pressure
Sensor
Supply Fan
Drive
Conditioned
Space

30. T HVAC & WATER: Supply Fan - Temperature Conditioned Space Supply Fan
Drive
Supply
Fan T

31. HVAC & WATER: Supply Fan - Smoke Extraction
Relief
Air Damper
Outside
Return
Smoke
Sensor
Supply Fan
Drive
Conditioned
Space
Close this
dampe r
Reverse
this fan

32. HVAC & WATER: Stairwell Pressurization
Fan
Drive Tp
Fire mode
function

33. HVAC & WATER: Parking Garage Ventilation FanCO
Sensor
Vent. Fan
Drive
Vent.
Fan
Smoke

34. HVAC & WATER: Fume Hood Fan
Drive

35. HVAC & WATER: Cooling Tower Fan
Temperature
Sensor
Cooling Tower
Fan Drive
Cooling
Tower Cells
Chiller
Condenser
Water
Pump

36. Flow Sensor Chiller Cooling Tower Strainer Condenser Water Pump Drive
HVAC & WATER: Condenser Water Pump
Flow Sensor
Cooling
Tower
Chiller
Condenser
Water
Pump
Drive
Strainer

37. HVAC & WATER: Examples

38. HVAC & WATER: Examples

39. HVAC & WATER: Examples

40. HVAC & WATER: Examples

41. HVAC & WATER: Examples

42. HVAC & WATER: Examples

43. HVAC & WATER: Examples

44. HVAC & WATER: Examples

45. HVAC & WATER: Examples

46. HVAC & WATER: Examples

47. HVAC & WATER: Examples

48. HVAC & WATER: Examples

49. HVAC & WATER: Examples

50. HVAC & WATER: Examples

51. HVAC & WATER: Examples

52. HVAC & WATER: Examples

53. HVAC & WATER: Examples

54. HVAC & WATER
Thank you