flowcon picv write out

7/28/2019 FlowCon PICV Write Out

1/17

Subject : Proposal of Dynamic Self-Balancing & Controls Solution

Company : Abex Engineering Pte Ltd

Product : FlowCon SME/SM

Dynamic Self-Balancing Modulating Control Valve

Prepared by : John Huang (9061 2332)

Abex Engineering Pte Ltd

Page 1 of 17


2/17

Contents Page to Page

1) Introduction to FlowCon International A/S 3 to 3

2) Illustration of Hydronic Balancing

a) Fractional losses 4 4

b) Hydraulic Interactivity 4 4

c) Control Valve Authority 5 5

d) Pipe Pressure Drop Transition Chart 5 5

e) Unbalanced System 6 6

f) Balancing Procedure 7 7

3) Needs & Types of Balancing System

a) Variable Flow System(MBV) 8 9b) Variable Flow System(MBV & P Controller) 10 11

4) FlowCon Dynamic Self-Balancing Control Valve 12 13

in Variable Flow System

5) FlowCon Dynamic Self-Balancing Control Valve

a) Pressure Independent Working Principle 14 15

b) SME/SM Selection and Flow Setting 16 16

c) FlowCon Project References 17 17

Page 2 of 17


3/17

FlowCon International A/S

FlowCon International A/S was originally founded in 1993 as a joint venture between the two dynamicbalancing market leaders in Europe and the USA. The fundamental purpose of this union was to

combine these two companies' knowledge for joint development of dynamic valves.

FlowCon International A/S was also appointed marketing and sales organization for the two owners

on all external markets world-wide.

Today FlowCon boasts more than 50 years of HVAC market experience. Our offices in North

Carolina, Singapore, Dubai and Denmark handle all sales and marketing world-wide. Furthermore

we act as the sales and marketing organization of Griswold Controls' products out of the USA.

We are 100% devoted to dynamic flow regulation and pressure independent temperature control.

We think balancing 24 hours a day and cannot suppress all of our exciting new ideas. FlowCon builds

on innovation and shifts from idea to action very rapidly. Our goal is to offer a better product range

and up-to-date Application know-how. Hence, we will be able, in cooperation with our distributors and

other business partners, to offer the optimum solution for a well-balanced HVAC system.

Page 3 of 17


4/17

Illustration of Hydronic Balancing

Figure 1: Frictional losses

Assuming the above pipe was given a constant flow & Differential Pressure, we will be able to see

the first hole will have the highest pressure and the last hole will have the lowest pressure. This is

because of frictional losses along the pipeline, the water will rub against the pipe inner surface losing

its energy/pressure to reach to the end.

Figure 2 : Hydraulic interactivity

If we close the first hole, we notice that the flow/pressure for rest of the holes is proportionally

increased. This is because of hydraulic interactivity, closing one hole will interfere the rest.

Closed

P Increase

Page 4 of 17


5/17

Control Valve Authority

Formula for Control Valve Authority;

In general, the smaller the percentage of the calculated authority, the lousier the control characteristic.

From the equation, we can see that most of the control valve is generally oversize due to the limited

available Kvs values. In most cases, the control valve fully shut P is taken during partial load condition.

Assuming a variable flow system with a pump head of 300kPa. Normally the pressure drop of thecontrol valve is 40kPa at design flow. At partial load condition the pipe frictions would transfer the 80%

of the pump head to the control value based pressure drop transition chart (Figure 3).

Then the calculated valve authority = 40/(300*0.8) =0.167

The calculated valve authority is 0.167 which means the control valve lifting of 10% would give us more

than the desired flow in the coil by 7 to 8 times. This means the low authority 0.167 would be too

sensitive for the controller to handle.

Piping Pressure Drop Transition Chart

Figure 3 : P transition from pipe to control valve

During 80% load condition, the pipe frictional losses will only be 20% as the control valve closes to

50% of the flowrate. This means the 80%of the pump head pressure will transfer to the control valve

during part-load condition.

Variable dependent on flow and opening of all the

other control Valves

Constant based on the selected Kvs value of

the valve which is limited to the increasing

Reynard series; 1.0,1.6,2.5 and so on. Nothing

in between.

80%

Flow (Q)

Coil Emission %

100%

50%

90%

70%

60%

40%

30%

20%

10%

100%

50%

80%

90%

70%

60%

40%

30%

20%

10%

80%

Flow

Piping P %

100%

50%

90%

70%

60%

40%

30%

20%

10%

100%

50%

80%

90%

70%

60%

40%

30%

20%

10%

Page 5 of 17


6/17

Unbalanced System

Figure 4 : System without Hydronic balancing

Figure 4 show a system which does not contain any form of hydronic balancing. The terminal units

nearest to the pumps will have overflow and the furthest terminal units will have underflow

because of pipe frictional losses.

In most practice, the pump head pressure is oversized to in order to pump enough flow to the

furthest unit. This practice will cause the control valve to work against a high close off pressure

causing failures to actuators continuously. The worst condition of an unbalanced plant is that it

will contribute a great amount of energy wastage.

Common problems in unbalanced plant;

a) Noise (hammering of control valves)

b) Insufficient capacity(Need to run more chiller)

c) Control problems(Control Valve Authority)

d) Long start up time(high room temperature Oscillation)

e) Energy wastage(Need to run more pump)

High

Differential

Pressure

Low

Differential

Pressure

Overflow

Underflow

Page 6 of 17


7/17

Balancing Procedure

Partner Valve

Figure 5 : Hydraulic Interactivity in Balancing

The common practices of balancing method in the market is Proportional or Trial Error Method.

Step required to do balancing:

All Distribution pumps must be operating at constant speed and full load to ensure

all terminal units has sufficient P.

All control valves must be fully-opened.

Strainers or any other congestion must be checked.

Flushed and completely clean without air lock.

Calibrated measurement instrument required.

While the pumps are running at full load, the terminal units nearest to the pumps will have overflow.

Balancing will begin by throttling the valves nearest to the pumps. By throttling the valves nearest to

the pumps, the available P will be pushed to the further terminal units and they will obtain an

increase of flow.

After throttling down the furthest terminal units, noticeably there will be an increase of P in the

terminal units nearest to the pumps. This procedure is repeated again and again resulting the

balancing valves throttled down to 10% to 15% for units nearest to the pumps and 25% to 35% for the

furthest units. The pumps are running at full load but the balancing valves are creating a huge amount

of resistance to limit the excessive flow. Eventhough the terminal units may achieve 90% to its flow

design, the balancing valves areinefficiently commissioned causing a great amount of energy

wastage.

Page 7 of 17


8/17

Variable Flow System - Manual Balancing Valve

Figure 6 : Variable Flow System(Manual Balancing Valve)

Optimisation & Control Strategy

Constant differential pressure of the system is maintained by modulating the speed of the pump. By

sensing the pressure fluctuations(Index Loop) during different load conditions, the speed of the pump

will be variable, hence the flow will be variable but the P is still maintained constant(DP Sensor).

System Analysis Results

The first benefit of this system is that the speed of the pump will react according to demand.Unfortunately, the drawback of this system is that the control valve authority varies because of having

a variable flow in the distribution loop. By having poor control valve authority, the output of the controller

hunts for the setpoint vigorously causing the room temperature to fluctuate continuously.

During low load, the pressure drop from the pipes will transfer to the control valve (because control

valve has the smallest orifice in the system when modulating). Channeling almost the entire pump

head to the control valves will cause overflow. The desired characteristic for power output is not

performing as expected due to overflows. Overflows will cause low T syndrome, therefore the

chillers will have to work inefficiently again.

Furthermore this system is sensitive to any hydraulic interactivities to any load conditions.

Extra installations of partner balancing valves are essential to perform proportional rule balancing.Eventhough the system is balanced properly, the operation performance is still subjective to any

movement of control valve.

DP

VSD

Page 8 of 17


9/17

Variable Flow System - Manual Balancing ValveSystem Analysis Breakdown

Design Calulation

- Traditional Calculation Required;

Kvs of the valve, authority on the Control Valves, presetting of Manual Balancing Valves

- Pump head calculation according to nominal f low

System Operational cost

- Very High pumping costs (Due to overflow phenomenon)

- Heat losses and heat gains on the pipeline are High

- Optimisation of pump head is Not Possible. Only if partner valves

are implemented. Use propotional commissioning method.- Control valves - good authority and high efficiency cannot be achieved -

higher room temperature oscillation(In case of modulation control)

- Low T Syndrome - has no control on return temperature, lower

heat-exchanger and cooling equipment efficiency

- Re-commissioning is needed from time to time.

Capital Cost

- Capital cost - High (Control valve + Manual Balancing Valves + Commissioning)

- Big partner valves are required

- More valves therefore higher installation costs- Commissioning of the system required

System Ready after Installation

- Balancing at full load - Very Good, in part load only Acceptable

- Commissioning of the system required in any cases

- In part load, flow will be 25-40% higher than designed flow, bigger pump is needed

- Pumping cost are far higher in part load operation

Other

- Closing pressure of terminal valves should be equal with the pump head at zeroflow, pressure is not relieved

- Pump usually is oversized and overloaded to ensure the correct condition for the

Manual Balancing Valve

Page 9 of 17


10/17

Variable Flow System

- Manual Balancing Valve & P Controller

Figure 7 : Variable Flow System(Manual Balancing Valve & P Controller)





Differential pressure sensor at the index loop should maintain the minimum specified P from the

P Controller.


By adding P Controller to individual loop, balancing valve at the main & riser is not required as

the membrane of the P Controller will react to the P fluctuations as a proportional controller making

the loop independent of each other. There will not be overflow between loop, but slight overflow during

part load condition from the manual balancing within the control loop. Good control valve authority

can be easily achieved by ensuring the closing pressure of the control valve to be 50% more than

the P Controller. Higher Pump head demand due to the extra pressure loss on the P Controller

(Pressure drop dependent on the flow of the loop).

Hydraulic Calculation is simplified by presetting valve on the control loop and sizing the authority on thecontrol valve.Commissioning of the system is not required only in case of a long control loop. Overall,

as compare to the manual balancing valve, this is better system.

DP

VSD

Page 10 of 17


11/17


- Manual Balancing Valve & P Controller

System Analysis Breakdown

Design Calulation- Traditional Calculation Required;

Kvs of the valve, authority on the MCV,

- Simplified hydraulic calculation (System Pressure sizing reduce to the

individual controlled loop)

- Presetting calculation within the controlled loop is needed

- Pump head calculation according to nominal flow

System Operational cost- Low pumping costs (overflow phenomenon with the controlled loop)

- Heat losses and heat gains on the pipeline are small

- Higher pump head demand - extra pressure loss on p controller required

- Optimisation of the pump head is practical

- Control valves- possible to achieve good authority and better efficiency

- lower room temperature oscillation

- Re-commissioning of the system is not required (only in case of long controlled loop)

Capital Cost- Capital cost - High (Control valve + MBV)-Teminal & (p controller + MBV)-Loop

- Expensive big p controller and manual balancing valve.

- Most number of valves in a system therefore higher installation costs

- Commissioning of the system not required (only in case of long controlled loop)- Variable speed pump is recommended (constant pressure characteristic)

System Ready after Installation- Hydraulic regulation only in terminal units and the p on the control

valve nearby is constant

- Balancing at full and part load - Good

- Commissioning not required only in case of long controlled loop

- Variable speed pump ensures energy saving

Other

- Closing pressure of control valves(teminal) should be at least 50% of the pressuresetting on the P controller

- Slight overflow during part load condition (manual balancing within the loop)

- Pump usually oversized or overloaded to achieve normal authority on the Control Valve

Page 11 of 17


12/17


- FlowCon Dynamic Self-Balancing Control Valve

Figure 8 : Variable Flow System(FlowCon Dynamic Self-Balancing Control Valve )





Differential pressure sensor at the index loop should maintain the minimum specified P from the

FlowCon Dynamic Self-Balancing Control Valve typically at 16/35kpa.


By applying the FlowCon PICV Method, all of the drawbacks of variable flow system have been solved.

The diaphragm of the SME/SM will react to P fluctuations as a proportional controller. There

is no overflow during part load condition; hence with unchanged characteristic output of the control valve,

the control valve authority is considered as 1. Without overflow, high efficiency in pumps and

chillers is ensure, eliminating low T syndrome, thus promoting comfort.

There is no extra installation of partner valves and balancing needed because all the terminal units

are pressure independent. Saving the installation, labour, commissioning, design calculations, time

and energy costs. Therefore, all complications of the system are well taken care of by using FlowConDynamic Self-Balancing Control Valve.

FlowCon PICV fulfilled three main key condition to ensure the lowest possible energy cost

1 Design flow available in all terminal units at different load connditions

2 Differential Prsssure Stability across all PICV

3 Flow compatible between the production and distribution

DP

VSD

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

PICV

Page 12 of 17


13/17


- FlowCon Dynamic Self-Balancing Control Valve

System Analysis Breakdown

Design / Sizing- Simple Calculation Method: neither Kvs, authority

or hydraulic presetting calculation

- Valve Authority 100% - pressure independent control

- Simplified flow setting calculation according to heat demand

- Pump head calculation according to min. p on the valve and

system pressure loss at nominal flow

System Operational cost- Lowest pumping costs (no overflow phenomenon)

- Heat losses and heat gains on the pipeline are minimal

- Lowest pump head demand

- Optimisation of pump head is recommended

- Control valves - 100% Authority and best efficiency - minimum

room temperature oscillation

- Re-commissioning of the system is not required

Capital Cost- Capital cost - GOOD (only 2 Way PICV)-Terminal

- Do not requried any balancing valve in the distribution system

- The least number of valves in the system (least installation cost)

- No Commissioning required- Variable speed drive is recommended (proportional characteristic)

System Ready after Installation- Hydraulic regulation only in terminal units

with 100% Valve Authority

- Balancing at full and part load - Excellent

- No Commissioning required

- Variable speed pump ensures highest energy saving

Other

- High close off pressure at 600kPa- No overflow at all load

- Simple and usual pump optimized

- Minimal total energy consumption(Production & Distribution)

- Maximum Energy Saving

Page 13 of 17


14/17

FlowCon Dynamic Self-Balancing Control ValvePressure Independent Working Principle

Figure 9 : Internal Structure of FlowCon SM

Figure 10 : Performance Curve of FlowCon SM

CONTROL VALVE

PCONTROLLER

Movement of the plug controls the

amount of water flowing thru the

valve regardless of changes in P1

and P2.

Water enters via a small passage and

builds up the pressure at P1, which

pushes the diaphragm upwards,

closing the outlet orifice area hence

keepingP at a constant level

Page 14 of 17


15/17

FlowCon Dynamic Self-Balancing Control ValvePressure Independent Working Principle

Figure 11 : Diaphragm position at higher Load Figure 12 : Diaphragm position at lower Load

The diaphragm position will vary whenever the P across the control valve changes (due to change in

the incoming pressure and movement of other control valves) the diaphragm will move to a new

position thus controlling the outlet opening orifice which brings a new equilibrium and keeps the

P at a constant level. Refer to Fig 12 for the relationship between the outlet opening and P.

For example, during a low load condition, the diaphragm senses a pressure build up from the inlet tube

below the diaphragm and then it will command the diaphagm to move upward to create a smalleroutlet orifice so that there will be no excessive flow going through. In short, flow will vary only when the

control valve modulated and the diaphragm will maintain a constant P thus a constant flow regardless

of pressure changes. Refer to Fig 9 for the performance of the valve.

Figure 13 : Diaphragm position vs P Changes

Position varies to keep

P at a constant level

Differential ressure increase

P Controller= P2-P3

Opening outlet orifice %

0 35kPa 400kPa

100%

50%

220kPa

Page 15 of 17


16/17

FlowCon Dynamic Self-Balancing Control ValveSME/SM Selection & Flow Setting

SME(15-40mm) SM(50-150mm)

Flow Setting on Valve Cartridge Flow Setting on Digital Actuator

The selection for the valve only required two parameters(Design flowrate & Pipe size connection).

For SME, simply select the f low from the chart and adjust on the cartridge from the valve. In-event of

any flow changes, flow can be easily change without tampering the pipe or insulation.

For SM, simply select the valve model(SM3.1) on the actuator and all the available flowrate will be shown

for selection. SM actuator also include feature like high IP rating at 54, information in the display such

as supply signal(2-10V), feedback signal(2-10V), current flow rate(L/S), battery condition and alarm. It

also come with password activation and fail safe feature.

Lastly, Kv value and authority of the valve does not need any calculation due to the pressure independent

characteristic which ensure 100% authority at all setting and P. With this, it not just increase the

control quality and precision, it also increase the flexibility of the system. The easy setting for FlowCon

makes late changes in the designs or subsequent system retrofits a breeze to implement in the system.

Page 16 of 17


17/17

FlowCon Dynamic Self-Balancing Control ValveFlowCon Project References

HotelCNA GROUPHyatt Hotel (Heat Recovery

System)

Singapore

Office BuildingBECA CARTEROne Marina Boulevard (NTUC

Centre)

Singapore

Office BuildingPARSONS BRINCKERHOFFSingapore Land TowerSingapore

Office BuildingJOHNSON CONTROLGreat Eastern @ ChangiSingapore

LabG-Energy GlobalShell Bukom (Central Lab)Singapore

Shopping CentreTHAM & WONGSembawang Shopping CentreSingapore

Integrated ResortPARSONS BRINCKERHOFFMarina Bay Sand IRSingapore

Country Project name Consultant Kind of building

Singapore SGX Center PARSONS BRINCKERHOFF Commercial

Building

Singapore May Bank Tower ALPHA CONSULTING Commercial

Building

Singapore Great Eastern Centre SQUIRE MECH Commercial

Building

Singapore Nayang Academy of Fine Arts SQUIRE MECH School

Singapore China Square Parcel 'G' Shop

Houses

SQUIRE MECH Shopping Centre

flowcon picv write out

Documents