HVAC & WATER Application note Imola – June, 19 2013 - 01

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.

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”

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

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

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

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.

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

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.

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

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

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.

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

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

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

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

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

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

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

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

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.

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.

WATER - MULTIPUMP: Fixed Speed Slaves (FSS)

WATER - MULTIPUMP: Fixed Speed Slaves (FSS)

WATER - MULTIPUMP: Fixed Speed Slaves (FSS)

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.

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.

WATER - MULTIPUMP: Variable Speed Slaves (VSS)

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

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

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

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

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

HVAC & WATER: Fume Hood Fan Drive

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

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

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER: Examples

HVAC & WATER Thank you