Introduction Danfoss Training Module-2 * * * Balancing Valves for Heating and Cooling Systems Back C O M F O R T C O N T R O L S Next - Page 2
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. Back C O M F O R T C O N T R O L S Next - Page 3
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…. Back C O M F O R T C O N T R O L S Next - Page 4
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. Back C O M F O R T C O N T R O L S Next - Page 5
The History of Danfoss Balancing Valve 1989 2003 2009 In 1989 Danfoss produced its first series of MSV commissioning and ASV automatic balancing valves. Back C O M F O R T C O N T R O L S Next - Page 6
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. Back C O M F O R T C O N T R O L S Next - Page 7
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… Back C O M F O R T C O N T R O L S Next - Page 8
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. Back C O M F O R T C O N T R O L S Next - Page 9
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. Back C O M F O R T C O N T R O L S Next - Page 10
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… Back C O M F O R T C O N T R O L S Next - Page 11
Why Balance a System? The system below has… a boiler, a 3 -way control valve, a controller, and thermostatic radiator valves. 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℃ 18℃ Back C O M F O R T C O N T R O L S 23℃ 25℃ Temperature required = 20℃ Next - Page 12
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. Back C O M F O R T C O N T R O L S 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. Next - Page 13
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 (m 3/h)… that can pass through an orifice at 1 Bar pressure. Back C O M F O R T C O N T R O L S Next - Page 14
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. Back C O M F O R T C O N T R O L S Next - Page 15
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. Back C O M F O R T C O N T R O L S Next - Page 16
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 Back C O M F O R T C O N T R O L S Next - Page 17
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 Back C O M F O R T C O N T R O L S Next - Page 18
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. Back C O M F O R T C O N T R O L S Next - Page 19
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. Back C O M F O R T C O N T R O L S Next - Page 20
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… Back C O M F O R T C O N T R O L S Next - Page 21
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. Back C O M F O R T C O N T R O L S Next - Page 22
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. Back C O M F O R T C O N T R O L S Next - Page 23
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. Back C O M F O R T C O N T R O L S Next - Page 24
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. Back C O M F O R T C O N T R O L S Next - Page 25
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. Back C O M F O R T C O N T R O L S Next - Page 26
Position in system The pipe-work gets bigger, the closer we get to the pump. For this reason Danfoss offer commissioning valves in sizes 15 mm, for local balance, up to 400 mm for large building balance. Back C O M F O R T C O N T R O L S Next - Page 27
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. Back C O M F O R T C O N T R O L S Next - Page 28
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 k. Pa (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 k. Pa 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 DN 20 valve (marked in blue). Back C O M F O R T C O N T R O L S Next - Page 29
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 [m 3/h] √ Differential Pressure [Bar] In this case we have flow rate of 0. 55 l/s which equals 2 m 3/h (0. 55 l/s * 3. 6 = 2 m 3/h): Kv = 2 [m 3/h] √ Differential Pressure [Bar] The differential pressure loss required in the valve is 20 k. Pa which equals 0. 2 Bar (20 k. Pa/100 =0. 2 bar): Kv (m 3/h)= 2 [m 3/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 Back C O M F O R T C O N T R O L S Next - Page 30
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. Back C O M F O R T C O N T R O L S Next - Page 31
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-F 2 valve, and for drain and isolation we have the MSV-S valve. Let us explore the range… Back C O M F O R T C O N T R O L S Next - Page 32
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. Back C O M F O R T C O N T R O L S Next - Page 33
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. Back C O M F O R T C O N T R O L S Next - Page 34
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. Back C O M F O R T C O N T R O L S Next - Page 35
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 BS 7350: 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. Back C O M F O R T C O N T R O L S Next - Page 36
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. Back C O M F O R T C O N T R O L S Next - Page 37
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 13 mm 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. Back C O M F O R T C O N T R O L S Next - Page 38
Danfoss Leno Range of Commissioning Valves For applications where flanged valves are required, Danfoss offer the MSV-F 2 valve in sizes 15 -400 mm. These have the option to come with variable orifice measuring points, or to use a separate fixed orifice measurement plate. The MSV-F 2 features: • a digital scale for easy setting and adjustment. • a Y-shaped design in sizes up to DN 150, to reduce the overall height of the valve, this is useful when space is at a premium. The MSV-F 2 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 PN 16 and PN 25 pressure range options. Back C O M F O R T C O N T R O L S Next - Page 39
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. Back C O M F O R T C O N T R O L S Next - Page 40
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. Back C O M F O R T C O N T R O L S Next - Page 41
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. Back C O M F O R T C O N T R O L S Next - Page 42
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. Back C O M F O R T C O N T R O L S Next - Page 43
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. Back C O M F O R T C O N T R O L S Next - Page 44
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. Back C O M F O R T C O N T R O L S Next - Page 45
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. Back C O M F O R T C O N T R O L S Next - Page 46
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 Back C O M F O R T C O N T R O L S Next - Page 47
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. Back C O M F O R T C O N T R O L S Next - Page 48
A final review In addition to commissioning valves Danfoss also offer a shut-off drain valve, type MSV-S. Back C O M F O R T C O N T R O L S Next - Page 49
A final review To commission the system, Danfoss offer a flow measuring device called the PFM 4000. 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. Back C O M F O R T C O N T R O L S Next - Page 50
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. Start C O M F O R T C O N T R O L S - Page 51
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