Transcript Slide 1

Introduction
Danfoss Training Module-2
******
Balancing Valves for Heating
and Cooling Systems
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Introduction
Hello and welcome to Danfoss training
module
‘Balancing Valves for Heating and Cooling
Systems.’
The purpose of this training module is to
examine the types of valves used to
balance hydronic systems, and how to
select the correct product for the
application they are to be used in.
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Introduction
This module takes around 20 minutes and
forms part of a
‘Continuous Professional Development’
training course.
Once 3 modules are complete you can
apply to Danfoss for
a certificate of your achievement.
Now let us begin….
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The History of the
Automatic Balancing Valve
The Danfoss Group is a global producer
of components and solutions for
Refrigeration & Air Conditioning, Heating &
Water, and Motion Controls.
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The History of
Danfoss Balancing Valve
1989
2003
2009
In 1989 Danfoss produced its first series of
MSV commissioning and ASV automatic
balancing valves.
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The History of
Danfoss Balancing Valve
1989
2003
2009
In 2003 Danfoss was the first major valve
manufacturer to introduce a combined
control and automatic balancing valve,
the AB-QM.
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The History of
Danfoss Balancing Valve
1989
2003
2009
The LENO MSV-O, unique commissioning
valve was launched by Danfoss in 2009.
By choosing Danfoss you have over 75
years of expertise behind you…
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What is a Balancing Valve?
A balancing valve is a device that controls
water flow and balances heat and cooling
distribution to different locations.
The purpose of the valve is to enable us to
supply the correct amount of heat and
cooling to each part of the building.
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What is a Balancing Valve?
Two types of balancing valves are used in
heating and cooling systems.
They are manual balancing valves, such
as commissioning sets,
and automatic balancing valves, such as
differential pressure control valves.
Danfoss have a full range of manual and
automatic balancing valves, and aim to
cover all applications.
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Why Balance a System?
Why do we need to balance our heating and cooling
systems?
A system without balancing is
in-efficient.
Let us look at an example of
why…
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Why Balance a System?
The system below has…
a boiler,
a 3-way control valve,
a controller,
and thermostatic radiator valves.
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However it has no balancing valves.
This results in the first radiator getting too much heat…
…and the last radiator not having enough heat.
16℃
23℃
18℃
25℃
Temperature required = 20℃
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Why Balance a System?
By putting a balancing valve on each of
our risers we can ensure they each get
the pressure and flow they require.
This means heat is correctly
distributed throughout the system.
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By getting the required amount of heat to each area of
the building, we ensure our users get the required
temperature in each of their radiators.
Improving user comfort and reducing energy usage
is the outcome of good balancing.
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How does a Balancing Valve work?
Let us look at the operation of
manual balancing valves.
These are commonly called
commissioning or double
regulating valves.
Commissioning works by
limiting the Kv value in the
balancing valves.
A Kv is a measure of an
orifice.
It is defined as the flow in
cubic metres per hour
(m3/h)…
that can pass through an
orifice at 1 Bar pressure.
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How does a Balancing Valve work?
By closing a commissioning
valve we reduce it’s Kv value
and thus the flow it can pass.
By setting all the individual
valves in the system, to deliver
the required Kv, we ensure each
area of the building gets its
correct flow.
By ensuring the correct flow to
each part of the system, we
ensure the correct temperature.
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Measuring on Commissioning Valves
To balance a system we need a method of
measuring and calculating the water flow.
We can therefore prove the correct
temperatures are being provided to all areas
of the building.
This measuring is carried out by a
commissioning engineer using a flow
measuring device.
Danfoss commissioning valves come with
measuring test points to enable orifice
measurement.
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Measuring on Commissioning Valves
The two types of commissioning valve
measuring points are fixed orifice and
variable orifice.
Danfoss MSV-O commissioning valves utilise a
separate Fixed Venturi orifice for flow
measurement.
This means the Kv of the measuring orifice
stays the same as the valve closes.
Danfoss MSV-BD variable orifice
commissioning valves differ from fixed orifice
valves as the Kv of the orifice drops as the
valve is closed.
Fixed Orifice
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Installation of Commissioning Valves
When using a variable orifice valve, the
commissioning engineer requires a Kv signal
chart to calculate flow from the measured
pressure.
Using an MSV-O Fixed Venturi orifice
commissioning valve makes commissioning
simpler than using a variable orifice valve
For this reason Danfoss recommend the use
of the MSV-O type valve where possible.
Fixed Orifice
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Measuring on Commissioning Valves
Traditional commissioning valves need to be
installed in a straight piece of pipe.
Then you would need to have a length of
straight pipe equal to 5 times the diameter of
the pipe before the valve (upstream).
After the valve (downstream) you'd need at
least 2 times the diameter of the pipe.
This is needed to guarantee the accuracy of
measuring the flow, which is otherwise
influenced by turbulence.
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Installation of Comissioning Valves
In Danfoss LENO valves, the flow direction is
not changed like in a traditional valve
The flow through the valve is symmetrical in
all directions.
This means the measurement is not influenced
by turbulence of other components in the
system…
… such as elbows or pipe-joints.
LENO MSV-BD and MSV-O valves can be
mounted in any spot that is convenient …
…and they will still enjoy the
exceptionally high measuring accuracy.
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Balancing Constant Flow Pumped Systems
We use Commissioning valves to balance
constant flow pumped systems.
A constant flow pumped system is where the
pump delivers a set-capacity of water at all
times.
Let us demonstrate…
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Balancing Constant Flow Pumped Systems
Here we have a system pictured with a
series of chilled panels in the occupied
areas of the building.
These have a commissioning valve to
balance, and a control valve to control the
temperature.
As parts of our system reaches
temperature, the control valve closes.
When the control valve closes it bypasses
the water away from the chilled panel.
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Balancing Constant Flow Pumped Systems
By bypassing the panel the
commissioning
valve receives a constant pressure, and
constant flow from the pump.
This makes a commissioning valve, which
is a constant Kv valve, suitable for this
application.
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Balancing Constant Flow Pumped Systems
In a constant flow pumped system, the
pump uses the same energy, whether the
system is open when people need cooling
or closed when people don’t.
This makes the system very energy
in-efficient.
Because of this in-efficiency, constant
flow pumped systems are becoming less
common.
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Balancing Constant Flow Pumped Systems
Variable flow systems are the
alternative to constant flow systems.
The use of variable flow systems is
covered in the Danfoss Training
Module 3-Pressure Control Valves.
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Position in system
In a constant flow pumped system, we
balance using the proportional balancing
method.
Using this method we require
commissioning valves:
• at all terminal units for local temperature balance.
• at all branches for circuit temperature balance.
• at all risers for area temperature balance.
• at the pump for building temperature balance.
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Position in system
The pipe-work gets bigger, the closer we get to
the
pump.
For this reason Danfoss offer commissioning
valves in sizes 15mm, for local balance, up to
400mm for large building balance.
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Calculating Required Selection and Setting
Now we have established in what systems
commissioning valves are installed, and
where in the system they are positioned,
we can then look at the selection of valve
size
and how to calculate it’s setting.
We will do this by using an example where
an MSV-BD variable orifice valve is being
selected.
Fixed orifice valves are calculated using
the
same method.
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Calculating Required Selection and Setting
For this example we will use a flow rate of
0.55 l/s, and a valve pressure loss of 20
kPa (or 0.2 Bar).
We calculate the size of valve required by
consulting a flow selection chart, this can
be found in the Danfoss product
datasheet.
0.55 l/s flow is marked on the chart and a
line (red) drawn directly through the 20 kPa
marker.
We follow this by drawing another line
(green) horizontally through the Kv
marker.
The smallest sized valve which can
achieve the required flow, is then selected.
This is a DN20 valve (marked in blue).
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Calculating Required Selection and Setting
After determining the required valve size;
the valve setting is calculated using the
following formula (water based systems!):
Kv=
Flow Rate [m3/h]
√ Differential Pressure [Bar]
In this case we have flow rate of 0.55 l/s
which
equals 2 m3/h (0.55l/s * 3.6 = 2m 3/h):
Kv =
2 [m3/h]
√ Differential Pressure [Bar]
The differential pressure loss required in the
valve is 20 kPa which equals 0.2 Bar
(20kPa/100 =0.2bar):
Kv (m3/h)=
2 [m3/h]
0.2 [Bar]
This formula requires us to square-root
this pressure loss (√0.2 = 0.447):
Kv=
2
0.447
=4.47
Our calculation gives us a Kv value of 4.47
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Calculating Required Selection and Setting
We then consult the setting chart in the
Danfoss
datasheet, and select the setting that gives
this Kv value of higher than 4.47.
The setting value of 4.2 is then set in the
valve.
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Danfoss Leno Range of Commissioning Valves
Danfoss offer two types of threaded commissioning
valve in the Leno range.
They are the MSV-BD Variable orifice commissioning
valve,
and the MSV-0 Fixed Venturi orifice commissioning
valve.
For flanged requirements Danfoss offer the MSV-F2
valve,
and for drain and isolation we have the MSV-S valve.
Let us explore the range…
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Danfoss Leno Range of Commissioning Valves
The LENO MSV-O and MSV-BD ranges are both twovalves in one.
They are a balancing valves…
…with an in-built 100% shut off valve.
And when the handle is pressed down to lock the
setting…
… the LENO transforms into a ball valve.
This means that with just a quarter turn of the handle
you close the valve and it's 100% internal leakage free.
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Danfoss Leno Range of Commissioning Valves
The ball valve is completely independent of the setting
mechanism so when the valve is opened again you return it to
the exact same position as before closing the valve.
For convenience there is an indication on the valve that
shows if the valve is open or closed.
When the valve is closed a red indicator covers the setting.
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Danfoss Leno Range of Commissioning Valves
MSV-O; Fixed Orifice
The MSV-O is a Fixed Venturi orifice commissioning valve
with many unique features.
Let us look at how these features affect installation and
performance…
The valve is very compact and features a removable handle.
Making installation in a confined space much easier.
The fixed orifice measuring points are positioned
independently of the setting, making calculation of flow
simple.
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Danfoss Leno Range of Commissioning Valves
MSV-O; Fixed Orifice
The valves measuring accuracy is plus or minus 8%,
down to 25% of the valve maximum Kv value, making the
valve much better than what is required by the
European standard for balancing valves BS7350:1990.
This European standard requires valves to be accurate
to plus or minus 18%, at 25% of the valves maximum
Kv value.
When using the MSV-O, locking the setting is extremely
easy. Once the valve is set we just push down the
head and the valve is locked.
This prevents the setting being tampered with and the
system balance being affected.
The Danfoss MSV-O features an in-built 100% shut off
valve.
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Danfoss Leno Range of Commissioning Valves
MSV-BD; Variable Orifice
In addition to our fixed orifice valves, Danfoss also offer a
variable orifice commissioning valve.
This is the Danfoss LENO type: MSV-BD
The MSV-BD is a user-friendly, versatile balancing valve
which features:
-A compact design with removable head.
-A lockable setting.
-An in-built 100% shut-off ball valve.
-The MSV-BD is also accurate to plus or minus 8%,
down to 25% of the valves maximum Kv value.
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Danfoss Leno Range of Commissioning Valves
MSV-BD; Variable Orifice
The drain point on the Leno MSV-BD enables the user
to drain the circuit by opening the measuring point
with a 13mm spanner.
This enables the system to be drained from the valve,
and removes the cost of installing separate drain
cocks.
The Leno MSV-BD uniquely features 360° turning test
points, that can be turned to enable measuring at any
angle.
This feature make it much easier for the
commissioning engineer to get the flow measurement
device onto the valve whatever the valve position.
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Danfoss Leno Range of Commissioning Valves
For applications where flanged valves are required,
Danfoss offer the MSV-F2 valve in sizes 15-400mm.
These have the option to come with variable orifice
measuring points, or to use a separate fixed orifice
measurement plate.
The MSV-F2 features:
• a digital scale for easy setting and adjustment.
• a Y-shaped design in sizes up to DN150, to reduce the
overall height of the valve, this is useful when space is at
a premium.
The MSV-F2 has a high Kv value in all sizes compared to
its competitors, this prevents the need to go to a larger
size of valve than pipe-work, to deliver the required flow.
Danfoss offer this valve in PN16 and PN25 pressure range
options.
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Danfoss Leno Range of Shut-off / Drain Valves
In addition to our commissioning valves, Danfoss have
another valve in the Leno range.
This is a high quality shut-off and drain valve, which is
Danfoss type: MSV-S.
The MSV-S is designed to be used in conjunction with
the MSV-BD and MSV-O valves.
In combination with a commissioning set, the MSV-S
ensures accurate flow, measuring, circuit shut-off,
and drain.
The Valve features:
A 100% closing shut-off function.
Practical and simple draining.
Easy mounting.
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Danfoss Leno Range of Shut-off / drain Valves
Now you are familiar with the LENO range we have one
more product to look at.
This is a device to enable flow measurement.
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What do we use to Measure System Flow?
Balancing of water systems require us to be able to
measure pressure and to calculate flow.
Danfoss offer a system to provide simple, accurate and
reliable measurement.
This is done using an instrument type: PFM 4000.
The PFM 4000 uses a main pressure unit which is
connected to the test points on the valves.
The measured pressure is sent via Bluetooth technology
to the HP IPAQ hand-held computer.
The setting value in the valve is entered into the software
on the hand-held computer by the user.
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What do we use to Measure System Flow?
By knowing the valve, its setting…
…and by measuring the pressure…
…we can calculate the flow through the valve.
When due to variations in the system, the actual flow is
not
at the required level to balance…
…we can use the PFM 4000 to calculate the correct
setting in
the valve, to achieve the balance we need.
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What do we use to Measure Flow?
The PFM 4000 comes with:
• A main pressure unit to measure the pressure.
• Hoses and nipples to connect to various types of test points.
• An HP IPAQ handheld computer with built-in software.
• A charger and PC synchronisation cable.
• In-built valve details and settings for all major
manufacturers
valves (not just Danfoss).
• The ability to calculate the required valve setting to achieve
the
correct flow.
• Export capabilities to enable project measurements to be
transferred to an Excel spreadsheet.
• The ability to print the measured data.
• A specially moulded case.
Pressure Unit
Hand-held
Computer
All other functions of the handheld computer can
also be used, such as Microsoft Outlook.
The PFM 4000 is a complete package to enable
accurate flow measurement and balance.
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A final review
You now have all the information required to specify,
select, and understand the Danfoss range of Manual
Balancing Valves.
Before we finish, let us review the information you
have learned.
Balancing valves are used to ensure the correct flows
to areas of a buildings heating or cooling system.
They work by closing the orifice in the valve, which
balances flow.
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A final review
Constant flow pumped systems use manual balancing
valves, these are commonly called commissioning
valves.
Variable flow pumped systems require automatic
balancing valves.
Danfoss offer a complete range of both automatic and
manual balancing valves.
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A final review
The Danfoss range has both fixed and variable orifice
commissioning valves.
The MSV-BD variable orifice valve features:
• 360° rotating test points.
• A built-in 100% shut-off isolation valve.
• A compact design and removable head for confined
spaces.
• A locking function with simple push-down action
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A final review
The Danfoss MSV-O valve features:
A digital pre-setting scale which is viewable from all
angles…
…and a Fixed Venturi orifice for simpler measurement.
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A final review
In addition to commissioning valves Danfoss also offer a
shut-off drain valve, type MSV-S.
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A final review
To commission the system, Danfoss offer a flow
measuring
device called the PFM4000.
The PFM 4000 features:
• The capability to measure pressure and calculate
flows.
• A hand-held computer with commissioning
software.
• The ability to export and print project measurements.
By selecting Danfoss you have every application
covered.
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Final Review
Congratulations for completing
your second training module!
You now understand all that is required to select,
and specify Danfoss balancing valves.
Module 3 has a title of ‘Understanding Pressure
Control Valves’
Once you have completed three modules you
can apply to Danfoss Randall for your
‘Continuous Professional Development’
Certificate.
For more information on Danfoss products or
for Danfoss-Randall’s contact details please visit
our
website at: www.danfoss-randall.co.uk
Thank you for your time.
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