Posted on Mon, May 07, 2012 @ 09:00 AM
This document details the flow verification and commissioning procedures in HVAC plants, water distribution can be accomplished at constant or variable flow. Each type of distribution system has advantages and disadvantages. Today variable flow systems using electronic 2-way control valves became generally accepted as the industry standard due to their benefits. The main reason for becoming the industry standard is reduced pumping cost, which is a result of pump head and flow. Meaning, the more control valves are closing, the lower the total flow. Another reason is that the plant can be designed with a diversity factor because flow is only needed where energy is demanded. Besides these advantages, there are disadvantages in today’s variable flow systems.
Posted on Mon, Mar 19, 2012 @ 09:00 AM
Multi-Function Technology (MFT), allows you to create custom solutions for individual applications, using the same programmable actuator. Whether you need a particular control or feedback signal, or need to change running speeds, MFT is the answer. It comes standard as a 2 to 10 VDC proportional control but can be reprogrammed on-site. You can modify voltage control, time proportional control, floating point, on/off and feedback signals too. In addition, MFT makes it easy to set parameters for running time, mechanical working range, address, status and diagnostics.
MFT offers many features:Configurable control and feedback signal type,variable runtime,flexible angle of rotation setting, scalable operating range,Min, Mid, Max override function, stored alarm information,data logging capability. Along with these feature are the benefits:
- Reduced number of actuators required in stock
- Flexibility to tune to each application
- Customized to fit application - to drive actuator less than 100% open/closed
- Optimized control resolution for every operating range
- Additional system control beyond modulation
- Ease troubleshooting
- Gather system data for optimization or diagnostics
Posted on Mon, Mar 12, 2012 @ 09:00 AM
The 6-way Characterized Control Valve (CCV) is the only one of its kind designed specifically for chilled beams and radiant ceilings. This compact valve has the functionality of up to four straight through valves saving on space, material and installation time.
Achieve Better Control and Cut Cost
Belimo 6-way Characterized Control Valves (CCV) feature heating and cooling circuits which are hydraulically decoupled because of the innovative ball design. Each sequence is controlled individually by the rotary movement of the actuator. The valve is bubble-tight in the closed position preventing energy losses and helps reduce operating costs.
The 6-way CCV offers:
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True close-off to isolate both heating and cooling loops.
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Two sequences with different Cv capabilities (eg. heatingand cooling)
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Linear flow characteristic
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Reduced installation cost by using only one coil for heating and cooling.
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One valve can support the coil with 2 different Cv values (heating and cooling).
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One valve performs change over and modulating control.
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Energy savings in close position.
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Reduced labor costs during installation.
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Only one analog output needed to control both sequences.
Posted on Mon, Mar 05, 2012 @ 09:00 AM
Belimo releases new white paper on Actuated Dampers in Smoke Control Systems covering smoke control strategy and tactics which defines the code requirements for fire and smoke dampers and their operation in case of fire.
The International Building Code (IBC. 2009) is the model code for most building codes in the United States. Along with the mechanical and fire codes, it defines the requirements for fire and smoke dampers and their operation in case of fire. The various codes have exceptions and specific cases where one or more of the smoke control methods discussed here may or may not be required. The purpose here is to explain how dampers operate in those systems so that the fire fighter, fire prevention officer, code official, consulting engineer, or building owner can better understand the technology.
The specific code requirements are not the subject, but it is sometimes necessary to keep them in mind. Chapter 3 of the IBC gives use and occupancy classifications; that is, the different activities and uses that define, for example, a mercantile occupancy or high-rise business occupancy. Chapter 4 gives special detailed requirements based on the classifications. Chapter 7 gives the requirements for construction, including fire and smoke dampers in barriers and walls. Chapter 9 covers the requirements for sprinklers, alarms, and smoke control systems. Chapter 10 is Egress Solutions and Chapter 30 covers elevators. These chapters cover most of the code provisions for fire and smoke dampers. Most of the provisions in the code are based on experience either in building construction or lessons learned in past fires or disasters. Some cities have damper requirements in the Mechanical and/or Fire codes also. For example, the New York City Codes have provisions in all three codes (NYC 2008). The NYC Mechanical Code, section 405, covers some of the requirements for high-rise business building manual or automatic control of some dampers and section 513 covers some requirements for smoke exhaust systems. Sections 606 and 607 cover smoke detector and some remote control requirements. The NYC Fire Code section 704.1 covers floor openings and shafts. Many other cities and states have codes with modified provisions based on the model codes. Many states have strong smoke control provisions as seismic activity can tear gas lines from the ground causing fire hazard and simultaneously breaking water lines thus disrupting sprinkler action. Learn more download our white paper now.
Posted on Mon, Feb 27, 2012 @ 09:00 AM
Air handling systems must be balanced to establish correct flow in all floors and zones of a building. Fire and/or smoke dampers are required in barrier walls for safety. This requires two dampers in modern systems - the fire and smoke damper and the balancing damper.
The locations for the fire and smoke dampers and the floor balancing dampers are shown in the drawing above. Typically the dampers are above the ceilings or below the floors where space constraints exist.
Shafts are protected by fire and smoke rated walls and are required to have fire and/or smoke dampers by the International Building Code. A combination fire and smoke damper is required where the floor duct leaves the shaft and passes through a out of the area where a fire starts to other areas via shafts, elevator hoist ways, chases, stairwells, and unsealed holes in walls.
At one time, two separate dampers were required at the shaft exit - a fire damper and a smoke damper. An extra balancing damper was also required, typically located just outside the shaft. This is a standard control damper without an actuator.
The balancer sets the correct flow volume. The FSAF24-BAL (-S) allows one damper to do the job of three, and also meets UL555 (fire) and UL555S (smoke) requirements. The fire and smoke combination damper is controlled by an actuator which is 3-postion, the mid-position being an adjustable balancing position.
The FSAF24-BAL has a maximum potentiometer that sets the open balancing position. The maximum potentiometer is adjustable from 20% to 100% open for balancing.
In case of fire (sensed by the thermal temperature limit) or smoke (sensed by either a local smoke detector or an area smoke detector and alarm system relay), the damper actuator springs full closed.
A 100% full open mode is provided for smoke management systems. If a fire fighters’ smoke control panel switch is set to open, the damper actuator drives 100% open, overriding the maximum balanced position. The FSAF24-BAL and smoke damper becomes a fully adjustable balancing damper.
Summary
The goal is to protect people from the effects of toxic smoke that is generated in fires. Balancing all supply ducts is required to maintain proper air volume or inlet static pressure for VAV boxes. Rather than installing two dampers - a combination fire and smoke damper and a separate balancing damper - one damper can be installed for both purposes.
Posted on Mon, Feb 20, 2012 @ 09:00 AM
There are numerous ways to design a method to protect air handler coils from freezing. Whatever your particular system requires, there is always one common denominator:
The outside air damper must close completely and reliably.
Here are a few simple steps to ensure that you’re using spring return actuators effectively for freeze protection, and that your outside air dampers close when you need them to.
Use the failsafe functionality of the actuator to close the damper.
Spring return and electronic fail-safe actuators are designed to close the damper during fail-safe conditions. Driving the actuator closed is not acceptable for freeze protection. The cause of the actuator closing may be a shorted wire to the signal input, a programming error or other event during which a drive signal cannot operate.
The freezestat (low ambient temperature limit) must be hard-wired to the actuator. Intermediate relays are acceptable, but all devices should allow the actuator to achieve its full fail-safe position.
Do not allow the control system to bypass the freezestat.
The freezestat plus actuator is a safety function that augments your control system. The control system alone cannot fully protect coils against extremely low outside air temperature entering the system. Wiring the freezestat to the software interlock control of fan shutdown and actuator spring return is not acceptable.
Cut power, not control.
In Belimo proportional actuators, wire #2 is 24 VAC/DC power, wire #3 is 2 to 10 V control signal input. The actuator’s fail safe function will only operate when power to the actuator is cut.
Verify damper position.
The freezestat could trip, giving the actuator a command to close, but freezing rain or other obstructions may block the damper. It is recommended to verify damper position with an auxiliary switch after the freezestat has tripped. Belimo actuators can either come with built-in or add-on auxiliary switches.
Test under real conditions.
The freezestat must be tripped and the sequence of operation as desired must occur. Cutting power to the actuator is not sufficient. The ideal test should be performed with low outside air temperature. The control signal should open the outside air damper then wait for the freezestat to initiate the freeze protection routine. In this way, the freezestat’s sensor location can also be properly determined.
Posted on Mon, Feb 13, 2012 @ 09:00 AM
This document details the flow verification and commissioning procedures in HVAC plants, water distribution can be accomplished at constant or variable flow. Each type of distribution system has advantages and disadvantages. Today variable flow systems using electronic 2-way control valves became generally accepted as the industry standard due to their benefits. The main reason for becoming the industry standard is reduced pumping cost, which is a result of pump head and flow. Meaning, the more control valves are closing, the lower the total flow. Another reason is that the plant can be designed with a diversity factor because flow is only needed where energy is demanded. Besides these advantages, there are disadvantages in today’s variable flow systems.
Disadvantages of Today’s Systems:
Time consuming balancing effort
According to its flow design each control valve requires a balancing valve to adjust the hydronic circuit. The balancing procedure dictates the quality of the system and requires highly skilled technicians and tools. During the balancing all control valves must be in their open position. However, as soon as the system is running, depending on different cooling or heating load requirements in the building, valves are permanently closing and opening which results in a dynamic system pressure. Balancing variable flow systems is time consuming and can be conducted only under “static” design conditions.
Rebalancing required when adding to system or remodeling
In a conventional system, if terminals are added the whole system needs to be rebalanced because some existing terminals must be throttled back. Or imagine a 10-story-building where every 2 months one floor is being remodeled in which balancing of the whole system is required after finishing each floor. Of course this applies also to buildings with changing tenants or new utilization of spaces.
Poor valve authority at average or low load
Only 1% of the time is a building typically running under design conditions. The other 99% the hydronic system needs to provide an average load of 50%. Thus flow is reduced to 20% and differential pressures across control valves increase. Since the Cv rating of the valve was sized for design conditions, the valve authority decreases and the modulating valve is downgraded to one acting open or close only. The result is anticipated hunting.
Potential spreading of control problems
Control circuits are interactive. Therefore when one control valve closes, the differential pressure on other circuits increase and the associated control valves must close to compensate. So when one or more loops are instable, control problems can spread to other control valves.
Low DT reduces efficiency
If flow is higher than required, DT will decrease and result in a cooling plant with lower return temperatures to the chiller and reduce the efficiency. If a chiller cannot run at peak efficiency, it is more likely that the next chiller in a series will be forced to start sooner than required causing additional electricity and maintenance costs.
The opposite happens in a condensing boiler, where a higher return temperature can avoid the condensing process when the dew point of the exhaust gases cannot be achieved.
The same phenomenon can happen in coils. In a heating coil for instance, overflow will result in a lower DT and decrease the coil’s performance which can result in discomfort due to a low room temperature.
The Revolutionary Solution:
With the PICCV all the disadvantages of variable flow systems are eliminated to represent the best hydronic solution for most HVAC-applications. The Pressure Independent Characterized Control Valve, PICCV, is based on the proven Characterized Control Valve, CCV, technology. In many tests and surveys, the CCV has outperformed globe valves due to a true equal-percentage valve characteristic and higher close-off ratings.
In a PICCV the CCV is combined with a differential pressure regulator. This regulator maintains a constant flow passing through the valve regardless of pressure variations in the system. The flow is held constant, but independent on the degree of ball opening. This is the most important at part-load; for instance when a PICCV with a nominal flow of 10 GPM operates at 3 GPM, a flow of 3 GPM is maintained.
The PICCV is available in the flow range from 0.5 to 100 GPM (1/2” to 2”) and a pressure operating range from 5 to 50 PSI.
Learn more of the advantages of the Pressure Independent technology.
Posted on Mon, Feb 06, 2012 @ 09:00 AM
Shell Point Retirement Community in Fort Myers, FL, is an extraordinary property. With over 400 acres and nearly 2000 residents, it is Florida's largest life care retirement community, combining all the services of a comprehensive staged elder care facility and the amenities of an all-inclusive resort. Also extraordinary is the fact that this sprawling property, which includes a 75-acre island and a wide assortment of medical, recreational, and living facilities, is served almost entirely by one central energy plant. The efficient and seamless delivery of heating and cooling to the outlying buildings is, in no small part, thanks to the nearly 1500 Pressure Independent Control Valves (PICCV).
Belimo has played an important role in Shell Point’s HVAC system since the property 
embarked on a 20-year multistage expansion several years ago. In addition to numerous new construction projects, this expansion included transference of several independently cooled buildings onto the central plant system. Ultimately the centralized cooling system would include 5 miles of underground piping. This massive system and a desire to resolve existing low ΔT problems led Shell Point Energy Plant Manager, Dan Parker, and Project Development Engineer, John Trowbridge, P. E. to explore Belimo pressure independent technology.
According to Trowbridge, pressure independent control eliminated the need for balancing newly constructed systems, as well as rebalancing systems already connected to the central load. Balancing would have been especially burdensome since all the air handling units already connected to the central plant would require rebalancing at the same time; a daunting challenge for even the most skilled contractor. This, along with the high differential pressures found in some areas of Shell Point, made Belimo PICCVs an appealing solution.
How the PICCV works:
The PICCV combines a differential pressure regulator with a two-way control valve and actuator for electronic flow control. The pressure regulator controls the amount of flow passing through the valve according to the change in pressure. All pressure changes are absorbed by the pressure regulator allowing the differential to be held constant over the control valve section, thereby providing consistent flow. This is different from conventional 2-way control valves, whose operation can be severely distorted by system pressure changes.
“The PICCVs circumvented the issues we had and provided us with a totally self-balancing
system,” says Trowbridge. “With the PICCVs, we are assured that the ΔT across the coils is at design conditions, working optimally, and pumping energy is minimized.” Because the PICCV has a very high close-off pressure rating, it can easily close off against the higher pressures found at some of the air handlers on the property, making it every bit as reliable as globe valves in many applications, often at a fraction of the installed cost. Even so, Dan Parker, a seasoned veteran in chilled water systems, was prepared for certain flow issues to crop up when the first PICCV controlled system went on-line. He was pleasantly surprised. “There was no impact on the system whatsoever. No increases in flow, chilled water demand, or pump power,” said Parker, adding “that since startup, no manual balancing has been required thanks to the dynamic system balancing the PICCV provides.”
Download complete case study.
Posted on Mon, Jan 30, 2012 @ 09:00 AM
Belimo showcased new products for 2012 at the International Air-Conditioning, Heating, Refrigerating Exposition (AHR Expo) in Chicago, IL at the McCormick Convention Center, January 23-25.
Energy Valve
- Documents and proves water coil performance using on-board data logging, trending and communication via BACnet.
- Improve coil DT using Belimo’s Delta T Manager mode to match
- the installed characteristic of the coil.
- Save pump energy by eliminating coil overflow.
- Improve plant performance by improving chiller or boiler efficiency.
- Achieve coil performance that follows the calculated design flow
rates exactly.
6-Way Control Valve
- Ideal for 4-pipe radiant ceilings and beams offering reduced wiring by using a single actuator instead of two.
- Eliminates the need for a change over valve and enables the use of a single coil for heating and cooling.
- True close-off to isolate both heating and cooling loops.
- Two sequences with different Cv capabilities (eg. heating and cooling).
- Linear flow characteristic.
New Generation Characterized Control Valves
- Increased differential pressure 30 psi to 50 psi.
- Improved media temperature range of 212°F to 250°F [100°C to 120°C].
- Standardized assembly screw: M4 screw for ½” to 2” valve bodies.
- Backward compatible with current actuator subassemblies.
UGSL1200 Retrofit Linkage
- Returns the Powermite MZ/MT short stroke valve back into service when the original actuator has failed.
- Easily attaches to existing valve bonnet and accommodates non-spring return or spring return actuators.
- Converts rotary actuator movement to a linear stroke of 5.5 mm with just 95° rotation.
EF Spring Return Actuators
- Reduce wiring and installation time while offering manual override on large dampers with Belimo’s newest high torque spring return solution – the EF.
- Rugged outdoor models are available with NEMA 4 (UL Type 4, IP 66) rating.
- Delivers 270 in-lbs [30 Nm] of min torque, driving dampers up to
66 square feet.
Posted on Mon, Jan 16, 2012 @ 09:00 AM
Reduce Cost and Save Energy!
Visit Belimo at booth 3749 to see a live demonstration of the new Belimo Energy Valve™, a two-way pressure independent control valve that optimizes, documents and proves water coil performance.
When water coils don’t operate efficiently, energy intensive components like chillers, boilers and system pumps consume more energy than they should. Unfortunately, most owners don’t know when coils are operating inefficiently or the impact this has on system wide efficiency.
The Belimo Energy Valve not only keeps owners and/or operators informed on coil performance, it has built-in Belimo Delta T Manager that helps operators analyze and fine tune performance under any and all conditions. The valve communicates directly with the Building Automation System (BAS) system so operators can continuously:
- Analyze the installed power efficiency of each and every coil
- Document and create history reports on coil performance
- Optimize performance using advanced algorithms
At the same time, the Energy Valve provides the same reliable, automatic, pressure independent flow control for which Belimo is famous! The Belimo Energy Valve has a schedule release date of April 2012.
Learn first hand at the AHR Expo, Booth 3749. Free pass to AHR Expo, January 23-25, McCormick Place North and South, Chicago, IL.