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Director, Systems and Solutions Trane Commercial Sales
Eugene Smithart, P.E. Director, Systems and Solutions Trane Commercial Sales Add your name and title slide and introduce yourself. (Note an (*) is placed throughout this script at locations where you need to advance the slide or to another point on the current slide.)
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The Goal? Agenda Real World Examples of Each
Highlights from EarthWise System Seminars A More Detailed/Advanced Look at Three Key Topics: Series Chillers and VPF Ice Storage LAT and Controls This section of the seminar will do three things: Provide a 80,000’ level view of the key lessons learned from the EarthWise Systems Seminars; take a more detailed/advanced look at three key topics addressed by the seminar: 1) Series Chillers and Variable Primary Flow Systems; 2) Ice Storage; and 3) Low Air Temperature and Controls and how they can help close chiller orders. To this end what we’ll be doing is a little like peeling an onion…we will find there are many, many layers of that onion and this session will reveal some of the most important layers. And finally we’ll look at real world examples for each of these three topics. What’s the *Goal of the entire Chiller Killer – II seminar and specifically portion which focusing on EarthWise Systems is… Real World Examples of Each The Goal?
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EarthWise™ Systems Service/Parts/ Solutions Products Controls
Emissions Energy Efficiency Products That said this portion of the seminar is not about safety, as important as that topic is, it about EarthWise Systems so let’s get started. EarthWise Systems are defined the same way the U.S EPA defines a program they call “Responsible Use”. Specifically, the EPA suggests that manufacturers, owners, system designers, need to focus on those technologies that will *drive emissions of all kinds to their lowest level and energy efficiency to it’s highest level. But this by itself is not enough. *This performance must be sustained over the lifetime of the product, system or service and then you have to *prove it or, said another way, document it. This fundamental will affect all industries. For Trane this means, low emissions and high efficiency must drive our “value added designs” *for our products. This also means *service, parts, solutions” play a critical role in our ability to deliver sustainable performance over the lifetime of the building. And while controls play a significant role in all of three areas, *controls are essential in providing documentation or proof of high performance on an ongoing basis. Controls
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Low Flow, Low Temperature, High Efficiency Systems
piping ~/–$ ductwork +/-$ air handlers controls chillers There are a number of types of EarthWise Systems but the one that has produced the greatest results is… Low Flow, Low Temperature, High Efficiency Systems. These systems allow us to*pull money from the ductwork and piping, if the interest is reducing first cost, or by keeping the sizes the same, improving system efficiency. And we can do that not only on the ductwork and piping but on the *air handlers, chillers and controls. And fortunately these designs give us the ability to offer the holy grail of HVAC systems…reducing both first cost and operating cost. And at the same time improving comfort, IAQ, and acoustics…something that few other system can do.
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Lessons Learned? How? Flow rates Fans Ductwork Pumps Piping
Supply temperature Flow rates Fans Ductwork Pumps Temperature differential How? By reducing supply temperatures and *increasing the temperature differentials, *which allows the flow rates to be driven down. In turn, this means that, for component sizing, we can drive down the size of *fans, *ductwork, *pumps, and *pipes. Yes but, what *lessons have we learned from the EarthWise System Seminars..that’s what we really want to cover. *We learned that we can and are doing this on the chilled water side of the systems, hence positively affecting chiller water side of the equation. We just need to do it more. However, what we are not doing is targeting the LLH applications (at least in most office) on the *airside. This is where at least half of the energy and first cost savings lie. This is where over half of the opportunity to mutz (mess with) competition lie. We know how to do this without having downdraft or condensation problems and competition doesn’t still we are passing it up…in most offices. An most importantly, by driving down the air temperature is how we lock in the low temperature design on the chilled water side. For example, with a 55F SAT design…that can be done with 44F leaving water temperature from the chiller. However, if you have 45F SAT you will not be doing that design with 44F LWT…not without a 210 row coil and a fan that can product 187” of static pressure!! Honestly our “not” focusing on the benefits of Low Air Temperature Airside systems is right next to nuts and something that we MUST address in our AOPs. Piping
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Chilled Water/VAV Systems
% of HVAC energy consumption Trane EarthWise™ System 83% 93% 70% 89% 80% Atlanta Minneapolis Los Angeles Denver Philadelphia Portland 100% Conventional System 100 95 90 85 80 75 70 65 60 TRACE LEED® And one of the best “Lessons Learned” is the ability of Trace to define how much energy savings is available via EarthWise Systems. Here in this chart it show saving ranging anywhere from 7% in Minneapolis to 30% in LA. *And as all of likely know by now, TRACE is exploding because of the impact of LEED.
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chilled water plant design... Old “rules of thumb”
44°F chilled water supply 10°F delta T across the evaporator - that’s at 2.4 GPM/ton 10°F delta T across the condenser - that’s at 3.0 GPM/ton But this is more important than just LEED. EarthWise Systems are literally rewriting the old rule of thumb. From this to…
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chilled water plant design... New “rules of thumb”
41°F chilled water supply 16°F delta T across the evaporator - that’s at 1.5 GPM/ton 15°F delta T across the condenser - that’s at 2.0 GPM/ton Potentially downsized the cooling tower This. However, there is nothing absolute about these numbers. The right supply water temperature may be 36 , 38 or 42F; the right delta T on the evaporator may be 18 or 20F; where as the right delta T on a close coupled cooling tower may be on 12F.
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How do you know? Yes, but how do you know what the right supply water temperature, the right delta T, the right supply air temperature is…the message is “Turn to TRACE” The key is we have the systems, applications expertise and tools to help you create the right balance between refrigeration and airside energy use. That’s where tools like Trace, System Analyzer, and Chiller Plant Analyzer are absolutely invaluable.
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Key Lessons Learned … Cooling towers Cooling coils Pumps Chillers
Air handlers Controls But let’s focus on the key “Lessons Learned” from the EarthWise System Seminars; lessons on everything from the Cooling Towers, Cooling Coils, Pumps, Chillers, Air Handlers and the Controls.
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lessons learned Cooling Tower Performance
“!Tower water should be hot!” Towers fans should use VFDs! 2nd The lesson learned for the Cooling Towers is *the “Tower water should be hot”! But what we also learned, in all but the most humid climates, is that *towers should have inverters. And these inverters typically have a pay back of less than a year. A one year payback is a 100% rate of return. Which stock would you not invest in if you could be assured of 100% rate of return. However, this is likely the* 2nd best ROI opportunity you have to offer. The *best is Chiller Tower Optimization which can pay back in as little as 8 months in some applications. Further, the Chiller Tower opportunity frequently turnout out to be the best way to get your foot in the door for applications where we don’t have either the controls or the service! 1st
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lessons learned: Cooling Coil Performance
“Chilled water should be cold!” Because of the pump energy savings 3rd The lesson learned on the chilled water side of the system is *”Chilled water should be cold”! This is because of *pump energy savings available by adding a VFD on the chilled water pump; especially in a Variable Primary Flow system. *This is likely the 3rd best return on investment for existing chilled water systems. *The 4th best is adding a VFD to the condenser water pump…especially if it has fairly large pump and motor. The key is this may be the 4th best return on investment but may be one of the 1st best ways to hurt York. York uses condenser water to cool their VFDs on their chiller. York chillers are very intolerant to condenser water flow changes. Their VFD and Soft Start Starters cooling relies on the differential pressure in the condenser inlet and outlet nozzles, with a 7' w.g. minimum. If there is not enough cooling flow to these devices, the VFD will overheat and the chiller will shut down on a VFD high heat sink temperature fault. There is no measurement of the condenser water differential pressure value, so the shutdown will occur without warning. VFD on the Condenser Water Pump 4th
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Pump Pressure Optimization
Another great control strategy, either for an existing building or new construction job, is pump pressure optimization. This is a control strategy that looks at the *valve position on the coils to reduce water side pressure to it’s lowest level and save pump energy? And if good for the chilled water side why not look at it for the hot water side as well?
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lessons learned LLH Chiller Performance
Yes the chillers consume more energy but more than offset by the ancillaries “Chillers need to be efficient!” What were the lessons learned on the Chiller Performance side of LLH systems? The key lesson is that, *yes the chiller will consume more energy but this increase in chiller energy consumption is more than offset by reduction in energy use of ancillaries. And the lesson learned is, in these systems the *“Chillers really need to be efficient”! In fact, efficiency is so important that for both *water and air cooled chillers should be factory witness tested. This is a wise investment that not only insures the efficiency of “that” specific chiller but also it provides a solid benchmark allowing for ongoing performance comparisons over the life of the chiller. It is like having a base EKG for the chiller. Knowing this base “EKG” and providing documented performance against this EKG via a Tracer Summit System is a prime example of delivering on the EarthWise System’s promise of documented, sustainable performance. A specific example of what this looks like is to use the factory witness tests to obtain the condenser approach temperature on water cooled machines. When one understands that fouled tubes are the number one contributor to degradation to the efficiency of the chiller and that the best indicator of fouled tubes is excessively high approached temperatures the two can be linked to provide ongoing levels of high efficiency. Or said another way, by knowing what the proper approach temperature (the base EKG) and then monitoring them with Tracer Summit and taking action when appropriate is a prime example providing the promised “documented sustainable performance”. Factory witness testing
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How can I eliminate the chiller’s kW increase for making colder water?
One of the questions that frequently come up is “How can I eliminate the kW increase for making colder water?”
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How can I eliminate the chiller’s kW increase for making colder water?
Ideal for use with variable primary flow: series chillers One of the ways to complete or partially eliminate the kW increase in making the colder water penalty is to put the chillers not in parallel, which is normally done, but to put them in series. One of the things we talked about in the EarthWise Systems Seminar is Series Chillers and Variable Primary Systems. Why series? Because you can save both first cost and operating cost…something Lee Cline will cover in more detail in his session. But also series piped chiller are ideal for variable primary flow systems. For a more detailed discussion on this and other series/variable primary flow systems let me turn the discussion over to Lee Cline.
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Chiller Killer II Seminar
Lee Cline, P.E. Senior Principal Systems Engineer Trane Commercial Systems Good morning . As Smitty said my name is Lee Cline. I have been with Trane for a little over 28 years now. I started in the CenTraVac technical service department, spent some time in BAS applications, and now work and LaCrosse applications and systems engineering group. This will be the part of the presentation that is digging into some of the technical nuances of each of these subjects, starting with Variable primary flow systems and series chillers.
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Series Chillers & VPF What?
Variable chilled water flow through the whole system Hopefully you know that Trane has a number of applications presentations and broadcasts on the VPF system so I am not going to dwell on the basics just a quick review. The Chiller Killer website lists a number of sources and resources for more information Shown here is a classic VPF system. One set of distribution pumps produces the pressure to move the water throughout the whole system. The flow varies through the loads, the pumps AND the chillers. The flow rate is controlled by the chilled water control valves and finally there is a bypass with a valve that is controlled to assure the chillers do not experience evaporator flow below the rated minimum.
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Series Chillers & VPF Benefits
Variable Primary Flow Reduces pumping costs Reduces first cost Adapts to system flow and temperature changes Advantages Trane chillers Advantages Trane controls Series Chillers Increases system efficiency Expands system range Eliminate Flow Transients Reduces pumping costs Advantage Trane controls If you’ve been selling chillers systems you know that the use of variable primary flow systems is exploding at a rate unequal to any other new system in our industry . The question is “Why is this? We believe it relates back to two things: one is that it provides incredible operating energy savings when compared to a constant flow system and secondly that it provides reduced first cost compared to a primary secondary chilled water system . As a secondary benefit it allows a chilled water system to better deal with low delta T. syndrome. Let’s take a closer look at some important considerations for variable flow systems.
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Series Chillers & VPF Objections
It looks risky! We’ve never done it. How do you control it? Is it reliable? So if those are the benefits of a VPF system what are the drawbacks . They are the things that you would imagine that cause anyone to resist change things like “it looks risky” and “we’ve never done it before” and “we don’t really know what the controls requirements are”. . Of course the number one Issue with any chiller plant is reliability and people want to know that the system is reliable . This is an incredible opportunity for Trane, we have the knowledge of the system and how to make it reliable. There are numerous stories of competitive control companies including the big boys not understanding or not wanting to tackle a VPF control job . So let’s dig into some of the important details again of this new system.
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Series Chillers Thermodynamic staging = efficiency
parallel chillers 44°F 54°F 0.611 kW/ton series chillers 48°F 40°F 56°F 0.605 kW/ton 0.544 kW/ton Here is an example of a typical parallel chiller system designed to slightly exceed ASHRAE 90.1 efficiency requirements. We see at ARI standard conditions the chillers efficiency is kW/ton slightly exceeding the minimum requirement. If we take those same basic chillers and apply them in a series configuration here is the performance. [Click] When you average the efficiency for the chillers you see that when we expand the delta T, and lower the flow the magic of thermodynamic staging kicks in and the combined average chiller kW/ton drops to kW/ton. Six percent better than our base system and ten percent better than 90.1 minimum requirement. The same price and 10% better efficiency – I bet you can sell that. [click] And we were able to reduce the pipe size from ten inches to 8 inches for an installed cost saving of about $25 per foot. But maybe 10% efficiency gain and lower first cost is not enough so lets look at what it does for system operation… 10” $200/ft 8” $175/ft $275k list price $272k list price Average kW/Ton = kW/ton 6% better efficiency (10% better than 90.1)
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variable primary flow systems Three Key Application Requirements:
Chillers must be able to accommodate a change of flow of at least 10% per minute; 30% or even 50% is even better CTV & RTWD variable flow compensation Chillers need to be selected with adequate flow turndown Strive for a turn down ratio of at least 2:1 of design to minimum flow. Minimum and maximum flows must not be violated A bypass is required These are the three primary requirements In designing and controlling the VPF system we’ve been promoting for quite some time now. As people get more and more comfortable with these systems they may push the envelope, now we’re learning things about selecting chillers. But before that, how many of you know what the variable flow compensation option is on the CenTraVac chiller? How many of you know that a similar feature is standard on the RTWD chiller and the CGAM chiller? This type of control sophistication is unavailable from any other chiller manufacturer to make sure that our customers appreciate and understand the value of these features and the Trane state of the art control they get with our products. There are three considerations in designing variable primary applications that need to be paid attention too. It is important to note that since the flow throughout the entire system is subject to change, and may change quickly, *chillers must be able to accommodate a change of flow of at least 10% per minute; 30% which is doable with screws and centrifugals and 50%, which is doable with centrifugals, is even better. (Presenters – for reference only see the specifics below.) It is essential the chiller manufacturers provide a chiller that can meet or exceed this requirement. *Under no circumstances can the minimum and maximum flows of today’s heat transfer bundles be violated. Tube erosion on the high end and lack of heat transfer on the low end can result in catastrophic failures. *To that end, a bypass with a control valve, or sufficient system 3 way valves, sized to support the minimum evaporator flow must be incorporated into the system. ****************************************** (For the speakers knowledge or reference and because there is a good deal of confusion on this topic the following information is provided here as a reference; not to be presented but as a reference in case the question is ask. Screw and Centrifugal Chillers without variable flow compensation: 10 % of design per minute to maintain +/-0.5°F (0.28°C) temperature control (sometimes termed “Process”) 30 % changes in flow per minute for temperature control of +/-2°F (1.1°C) (sometimes termed “Comfort”) CenTraVacs with variable flow compensation option: 25 % of design per minute to maintain +/-0.5°F (0.28°C) temperature control (sometimes termed “Process”) 50 % changes in flow per minute for temperature control of +/-2°F (1.1°C) (sometimes termed “Comfort”) For Scroll Chillers: 10 % of design per minute.
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Minimum flow rates – PARALLEL chillers – base system
Chlr 1 Capacity (tons) 500 Chlr 1 Design Flow (gpm) 1000 Chlr 1 Min Flow (gpm) 400 Chiller 1 Turndown 2.5 to 1 2 Chiller Unloading To drive the point home that adequate flow turn-down is important lets take a graphical look at the operation of a variable flow chilled water system with different chillers. We’ll take two chillers with a 2.5 to 1 turndown ratio, representing a minimum flow of 400 gpm and apply them in a VPF system. [Click] First lets plot the system load vs system flow curve. Because its variable flow we know that system with air handlers that are operating properly flow is proportional to system load. Let’s start and run the first chiller. Here we see the chiller load up. The blue triangle represents the loads where by-pass flow is required in addition to system flow to satisfy the chiller’s minimum flow requirement. We at below about 20% system load bypass flow is required. What happens when we start the second chiller? Even though the flow splits between the two chillers there is still enough that no by-pass flow is needed when the second chiller start. One more step. Lets unload the system with two chillers running and observe what happens. We have a this system turning the lag chiller off when the two chillers are unloaded to about 35% load. That means the lead chiller will be left with about 70% load to carry. And we see that at for system loads between about 40% and 35% a small amount of by-pass is required. This is actually a quite nicely behaved system. How about another example. 2 Chiller Loading 1 Chiller Loading System Load
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Minimum flow rates PARALLEL chillers – less turndown
Chlr 1 Capacity (tons) 500 Chlr 1 Design Flow (gpm) 1000 Chlr 1 Min Flow (gpm) 700 Chiller 1 Turndown 1.4 to 1 2 Chiller Unloading This example charts the behavior of a VPF system with two chillers in parallel, each will a 1.4 to 1 turndown ratio. Their minimum chilled water flow rate is 700 gpm. [Click] As expected with a lower turndown ratio more by-pass flow is required. This might be a good time to point out the impact of this on pumping energy. How much flow does the pump have to pump – the system flow or the system + bypass flow? The system plus by pass flow! So if we look closely, with one chiller operating at all system loads below about almost 20% the pump is pushing more flow through the by-pass then the system – at the system required pressure. More on that in a moment. Lets start the second chiller. Now because of the lower turndown ratio, when we go to start the lag chiller – or more correctly when we open the lag chiller’s isolation valve we immediately need 400 gpm of by-pass flow to ensure we meet the minimum operating flows of both chillers. Lets unload the system with these chillers two chillers and see what happens. At 35% system load we need 700 gpm of flow through the by-pass to meet the chiller minimum flow requirement. As much as is being used by the system for the cooling load. With two chillers running the pumps must process at least 1400 gpm of chilled water, at the system required pressure, no matter the system load. One more example… 2 Chiller Loading 1 Chiller Loading System Load
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Minimum flow rates SERIES chillers – less turndown
Chlr 1 Capacity (tons) 500 Chlr 1 Design Flow (gpm) 1000 Chlr 1 Min Flow (gpm) 700 Chiller 1 Turndown 2.8 to 1 2 Chiller Unloading This diagram shows the operation the same chillers as that previous example. They have the same minimum flow rate of 700 gpm. But because they are configured in series and see the total system flow their effective turndown ratio is 2.8 to 1 turndown ratio. [Click] The lead chiller loads up just as before. Even though it is in in series it still has a minimum flow requirement of 700 gpm. But now we start the second chiller. Absolutely No by-pass flow is required to start the second chiller. This greatly simples the system operation. And in fact, as the system unloads no by-pass is required all the way do to when the lag chiller is turned off. Contrast that to the same chillers in parallel. 2 Chiller Loading 1 Chiller Loading System Load
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Series Chillers Expand system operating range
Pass Min Flow (gpm) RTHD 250 std-eff 2 3 RTHD 250 hi-eff RTAC 300 std-eff RTAC 300 hi-eff RTWD 120 std-eff 101 67 RTWD 120 hi-eff 123 82 gpm/ton [12° dt] (gpm) Turndown ratio 500 558 574 230 244 gpm/ton [16° dt] (gpm) Turndown ratio 375 418 430 172 183 You realize how important this is when you look closely at the operating flow requirements of different scroll and screw packaged chillers and their impact when applied in VPF systems. [Click] Here we see that even with a relatively high flow system of 2 gpm per ton, or 12 degree delta T, we need to apply three pass evaporators to achieve a 2 to 1 turndown ratio. Note that the high efficiency RTHD only has a 1.67 to one turndown ratio even in a three pass configuration. If we go to a not uncommon 16 degree delta T system only the three pass RTWD chillers have a two to one turndown ratio. Clearly the application of series – VPF will often be appropriate for these chillers.
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Series Chillers & VPF What about pumping horsepower?
RTAA110 Parallel Load Pump Flow Sys PD HP 100 310 70.0 5.5 90 279 60.5 4.3 80 262 52.4 3.5 70 45.6 3.0 60 39.7 2.6 50 155 36.0 1.4 40 132 30.6 1.0 30 27.5 0.9 20 25.2 0.8 10 23.8 RTAA100 Series Pump Flow Sys PD w/ CV opt. HP w/opt 310 88.4 7.0 279 75.4 74.4 5.3 248 63.8 61.4 3.9 217 53.5 50.5 2.8 186 44.6 40.6 1.9 155 37.1 32.1 1.3 124 30.9 24.9 0.8 120 27.6 20.6 0.6 25.3 17.3 0.5 24.0 15.0 0.4 What is the first and biggest fear of going to series chillers? Pressure drop and its impact on pumping energy. This table brings everything we’ve looked at so far down to energy. The left side of the table shows the flow and SYSTEM pumping horsepower for two 110 ton chillers in parallel. [Click] The right half shows the pumping horse power for two 100 ton chillers serving the same load. Ignore every thing but the green shade areas. What they show you are the system loads where each application uses the lower amount of energy. Admittedly we helped the series application a little with pump pressure optimization. But I refuse to apologize for leveraging our deeper control knowledge to make a good application better.
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VPF System By-pass flow control lessons
Size bypass line for minimum flow Size bypass valve for minimum flow Select DP transducer or flow meter for minimum flow Select chiller proof-of-flow device for minimum flow Lets wrap this up with a couple reminders on design and control of the by-pass line. [Click] The first step to good flow control is proper line and valve sizing. Oversizing will result in control stability problems, or hunting if you will. The rule of thumb is to size this line for the chillers’ highest minimum flow, and probably be on the small side of that. Smaller sizing will provide more control authority and more stable control. In addition to properly sized we would like the valve to have a relatively linear flow to position characteristic. This can be accomplished in several ways: first with a ball valve, or pressure-independent valve, these are available in smaller sizes and so may be appropriate for the chilled water plants we’re discussing today. When greater flow is required designer often look to butterfly valves, but a linearly characterized type must be specified. The best recommendation we can give is to talk with a valve manufacturer representative and have them help select the best linear curve valve available in the size that’s required. Another perspective is that you should think in terms of an “industrial quality valve”, this is no place to try to save a nickel or allow a contractor to ”value engineer” the design. One other caution is again since the by-pass is close to the chiller plant make sure the actuator has enough torque to modulate and close off against the pump pressure. The other critical element in control of the by-pass is selection of the chiller flow metering technology. In most cases we accomplish this by measuring the pressure drop across the chiller’s evaporator and calculating the water flow from that value. This method has worked well on a number of jobs. When selecting a pressure transducer or flow meter as well as a proof-of-flow device, it’s not only important to pick a high quality device, it is critical to select it for accuracy in the correct flow range. And just like for by- pass line sizing, that range is NOT around the chiller design flow. It IS at chiller minimum flow! So, whether a designer or installer you need to know the chiller’s pressure drop at minimum flow and use THAT to pick the appropriate range for the instrumentation. We want accuracy at minimum flow conditions. This may result in less accuracy at design conditions, but that is not the priority for the control we are trying to achieve. [ Click ] Finally because responsive and accurate control is required both the flow indicating transducers and the valve control must be hardwired to the same controller. The lag that would be expected with trying to communicate between controllers would probably result in unacceptable control. And once again, this is not an area where value engineering should be allowed to compromise accuracy or reliability.
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VPF Proof-of-Flow Orange Research Model 1516 DP switch W.E. Anderson H3 series DP switch from Dwyer Thermal dispersion flow sensor - IFM Effector Last thing. Paddle type flow switches make really good door stops in Variable Primary Flow chiller plants. Here are three options that a number of our offices have used for proof-of-flow. Please remember, just like for flow measurement, choose them for the pressure or flow conditions at the chiller’s minimum flow. And if you have questions give us a call. We will do our best to help you out.
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Proof-of-Flow IFM Effector
Phone: Website: Purchase online at: Technical resource: Chad Mosier HVAC Industry Specialist Phone: Key Points: The last device on the list is the IFM Effector. Think if it as a hot wire anemometer for water. A number of offices are using this to solve tricky proof-of-flow nuisance problems It seems to be accurate easy to set up and bullet proof. The only maintenance is pull the probe once a year and wipe any fouling off of it. It costs about XX times a good DP – half the price of a service call?
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Where Else Use Series? ??? By the way series, thermodynamic staging and VPF has all kinds of applications not to forget about. Key Points: What does the series configuration do for a chiller plant? It not only provides the efficiency of thermodynamic staging It provides the designer the flexibility to maximize the strengths of many different cooling technologies Such as…
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series chillers Ideal application for:
Free Cooling Free cooling is a awesome application for series. It allows more hours of free cooling operation. Both plate frame or chiller based free cooling can be applied this way. With chiller free cooling the extra cost and very significant maintenance of the plate frame heat exchanger is eliminated. And who is the only manufacturer that makes a real water-cooled free cooling chiller?
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series chillers Ideal application for:
One AFD Here’s a way to beat York at their own game. York loves AFDs – But fumbles on VPF systems. If a customer wants the upstream chiller to be able to make systems design chilled water temp in the event the downstream chiller is unavailable applying a VFD makes great sense because it is operating at much lower than design lift conditions whenever both chillers are operating.
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series chillers Ideal application for:
ASHRAE 90.1 Section requires heat recovery for… Heat Recovery We are seeing a real surge in interest in heat recovery. Not only because of the ASHRAE requirements but to help with energy costs, LEED points and because of escalating heating costs.. FREE energy is just hard to pass up. ASHRAE/IESNA 90.1–2004 requires heat recovery for service water heating if [SLIDE][CLICK] the facility operates 24 hours a day, rejects more than 6 million Btu/hr at design conditions, and has a design service water heating load over a million Btu’s per hour. Hospitals Correctional facilities Hotels High rise residential with central plant In addition to the service water heating requirement, 90.1 does not allow simultaneous heating and cooling of supply-air streams – whether it’s done using reheat, or by mixing of hot and cold air streams. There are exceptions that allow reheat to be used. For comfort cooling applications, the zone airflow must be reduced to the greatest of: That required for ventilation by ASHRAE Standard 62, 0.4 cfm/ft2, 30% of design airflow, or 300 cfm. Many VAV systems will be able to reduce zone airflow to one of these limits prior to reheating the air, and therefore comply with 90.1 However a constant volume system would likely have to use the final exception. That is, recovering 75% of the reheat energy on-site, such as from a chiller’s condenser.
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series chillers Ideal application for:
Series Counter-Flow Last application for series I’m going to mention is series-counter flow. It’s the ultimate in systems thinking and really does save energy. It’s a harder sell in small plants but when your really good it can be done. The only reason it’s a hard sell is that it’s different and engineers are risk adverse.
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series chillers & VPF Trane Advantages
Chiller minimum flows Trane chillers use less tubes for a given efficiency Our compressors ARE more efficient ! System flow rate-of-change Variable Flow Compensation gives Trane chillers the most robust control in the industry We know how to do it Why are we spending time on this? Is it just because it’s good for the owner? Yes it is good for the owner but it’s good for YOU too! Trane compressors and refrigeration systems are more efficient. That means for the same efficiency we can have a lower minimum flow. That’s great news for any VPF system, parallel or series. Our controls are better. That results in better chiller and system operation. An features like Variable Flow Compensation that you can sell to your owners and engineers that demonstrate Trane’s technological leadership and systems knowledge. And finally, what do JCI, Siemens and the rest want to do in any chiller plant? As little as possible. And despite the lip service they will give to system control and optimization for the most part they really don’t get it. Alan’s got some experience to share with you to help drive that home.
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series chillers & VPF What did we see?
We know what the risks are We done it a lot It is easy to make reliable There are many benefits There are may applications
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Airside: What’s different?
Supply air Room setpoint Airside delta T 55°F 75°F 20°F Common practice Low air temp.system 45 – 48°F 77°F 32°F Lowers the required air flow by 30-40% Now let’s switch to the airside and see what is different. *In traditional systems the supply air temperature is 55°F, the room coiling set-point is 75°F and the Airside delta t is 20°F. *For the same load, a Low Air Temperature System, have a supply air temperature of 45° to 48°F. For high efficiency centrifugals the right balance between refrigeration and airside energy may be in the 45°F range. For screw chillers which are somewhat less efficiency, the right balance may be more in the 48°F range. Our experience, supported by information taken from the ASHRAE Fundamentals section on "Thermal Comfort“, has been that we can set the room cooling set-point one or two degrees higher, and still have the same or better comfort, because of lower humidity. This results in a Supply Air Delta Tee of 32°F. *Putting this all together means we have lowered the required air flow by typically 30 to 40%. And what LAT on the airside does for us is three things: The airside is where at least 50 percent of the first cost and frequently 50 percent of the energy cost saving potential reside. To forgo these is to miss at least half of the opportunity offered via EarthWise Systems. This drives the need for high efficiency chillers which inherently advantages us. Locks in the low leaving water temperature requirements for chillers – i.e., it locks in 2 of the 3 critical success factors: low temperature and high efficiency. This is a price example of how to use Airside Systems to sell Chillers. Can cut the airside fan BHP by nearly 50% Drives the need for high efficiency chillers Locks in the low leaving water temperature requirements for chillers
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CDQ EarthWise™ airside system for floor-by-floor applications OA CA OA
SA to occupied space MA This is what we called in the EarthWise System Seminar “the million dollar slide”. This application uses a *dedicated 100% outside air unit, typically provided with both an energy recovery and CDQ wheel. Getting CDQ specified and held helps us lock up the job…or at least making it much more complicated for competition. With CDQ on the job they are play our game, not theirs. And the prime benefit for the customer is to produce OA so dry that the indoor coils run a great percentage of the year dry. Because dry coils have up to 40% lower pressure drop and over 60% less fan energy to over come the associated coil pressure loss. *The cool dry air is metered into the equipment room via a VAV box. That’s the outside air. *Here is the return air. *The mixed air and the supply air for the system. The stacked model M series unit is also ideal for low air temperature applications: it’s a blow through – meaning that you don’t have to make extraordinarily cold air to make cold air; the stacked arrangement reduces foot print, and the M series unit is in a conditioned space it does not sweat.
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CDQ EarthWise™ airside system for floor-by-floor applications
OA EarthWise™ airside system for floor-by-floor applications OA CA EA EA EA RA SA to occupied space Ventilation Reset ASHRAE 62 Fan Optimization ASHRAE 90.1 MA Another major focus of the EarthWise System Seminar is the use of Direct Drive Plenum Fans. The fact that DDPFs are quieter, more efficient, and requires less space are all important factors. Plus a standard VFD can not only slow down but can also speed up the rpm of the motor by up to 40 to 50%. This frequently allows selection of fan that is in it’s efficiency “Sweet Spot” on the fan curve. The elimination of the belts, the belt loss, the belt maintenance are significant advantages. Finally the fact that the diameter and width of the fan can be changed to optimize performance are all advantages of the Direct Drive Plenum Fan. These fans are also provided, as a standard, with a *Piezometer providing excellent flow measurement with zero pressure drop. We want the specification to call for a full air flow monitoring station!! Competition is providing and commissioning a full air flow monitoring station and we are providing a simple tube! While these are good advantages, the greatest value for owners lies in the area of * controls. A prime example is Ventilation Reset, *which is referenced in ASHRAE 62 and *Fan Pressure Optimization *which is required by ASHRAE 90.1. What do we have to do to provide Ventilation Optimization? *Check this box. What do we have to do to provide Fan Pressure Optimization? *Check this box. And what does competition have to do? Spend hours and hours of programming and frequently they still can get it done. This is wonderful pain for our competitors. Yes but what’s the best way to get a feature like Fan Pressure Optimization held. Require that the box that is setting the required static pressure be listed on the workstation. At startup allow the owner’s and engineer’s representative (along with the Trane Sales Engineer) to do to any room and turn the thermostat to it’s lowest temperature. What had better show up at the workstation is that zone. If not, competition can stay on the job, for weeks or months if needed, to insure it does. *The last component is the exhaust air system. This is just a VAV system with negative pressure in the duct. *The dampers are Trane VAV boxes controlled by floor-by-floor building pressurization controls which, for high rise applications, can help minimize stack-effect problems. An how are we providing this feature? By using something that has been provided on every IntelliPak VAV unit for years and years…StatiTrak. This is something competition typically does not have a clue how to do. By specifying the Ventilation Reset, Fan Pressure Optimization, Floor-by-Floor pressurization and Supply Air Reset we drive our control competitors nuts!! And finally, if *fan pressurization is good in the supply why not use it in *all of the ducts!! *Getting these items speced and held is what it looks like to *“Be the Bear”. Floor by Floor Pressurization Fan Optimization
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CDQ™ One last airside topic we want to discuss is the CDQ.
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how it works CDQ Desiccant Wheel
high Typically at mixed-air conditions Typically at leaving-coil conditions ability to hold water vapor I’m sure most of you know how CDQ works…so to just the highlight. CDQ uses a type III desiccant that had the property of wanting to absorb moisture when it is around high relative humidity conditions and give it up when it is around RH that is below 70%. Type III (CDQ) low 20 40 60 80 100 relative humidity, %
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Cool, Dry, Quiet (CDQ™) OA MA' MA RA CA cooling coil Trane CDQ
75°F DB 63°F DP 80°F DB 60°F DP MA' MA RA water vapor CA The CDQ concept places a this type III desiccant wheel in series with the cooling coil, with the regeneration side of the wheel upstream of the cooling coil and the process side downstream of the coil. Moisture transfer occurs within a single air stream: The CDQ desiccant wheel adsorbs water vapor from the process air downstream of the cooling coil, enabling the system to deliver drier supply air (at a lower dew point) without lowering the coil temperature. When the wheel rotates, it releases the adsorbed water vapor to the air upstream of the coil—and the cooling coil gets a multiple chances to remove the transferred water vapor via condensation. 50°F DB 49°F DP 55°F DB 43°F DP cooling coil Trane CDQ desiccant wheel SA
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CDQ OA 100°F DB 74°F WB Wetter RA 62°F DB 50% RH Cooler Warmer MA
53.5°F DP Dryer 110 30 40 50 60 70 80 100 90 dry-bulb temperature, °F wet-bulb temperature, °F 180 160 140 120 100 80 60 40 20 humidity ratio, grains/lb of dry air MA' 76°F DB 58.5°F DP CDQ requires: less cooling tons less reheat CA 51°F DB 49°F DP SA 55°F DB 42°F DP MA' To really understand CDQ is to see its operation on a psych chart. Here we see the return air, outside air, and mixed air points. *When the mixture goes through the top portion of the CDQ wheel – note what happens; the air gets wetter and cooler because of evaporative cooling. *The mixture goes through the coil and then *through bottom side of the CDQ wheel. As it goes through the CDQ wheel the air gets warmer (latent head of adsorption) and dryer. A prime example of where CDQ presents an ideal solution is hospital surgical suites. These suites are frequently trying to hold 62F air and 50% relative humidity. In the past to hand this application would have required the use of a separate glycol chiller producing cold enough glycol so the *airhandler could have in turn produced 43F air. Then one would have had to *reheat that air. *So the key advantages of CDQ is that is requires less cooling tons and less reheat. OA CA MA CAreheat RA SA
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Cool, Dry, Quiet (CDQ™) 100% RH 70% RH preheat coil O OA MA' MA
90°–140° F water vapor RTWD heat recovery chiller CA Yes, but what happens if this is a 100% OA unit and it’s a rainy day. Now the OA is essentially at *100% RH and the top portion of the CDQ would simply fail to regenerate. In this situation you *can add a degree of heat with a preheat coil such that the *relative humidity is brought back to the less than 70% range. One of the most efficient ways to add that heat is via a *heat recovery chiller like the new Trane RTWD which can produce up to 140 F leaving condensing water temperatures. This is but one good application of heat recovery. Combining both CDQ and heat recovery together is a perfect example of “positioning a job for sale before the job ever bids”. 38°–45° F cooling coil CDQ desiccant wheel SA
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Before I leave the discussion of CDQ I want to demonstrate a tremendous new tool that is available. It’s called the Climate Changer Configurator Program. This program has a number of Climate Changer Configurations already built into the program. For example here is the “Million Dollar Slide” configuration. When I click on that option now I can add…
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10,000 Information like Supply Fan Airflow – in this case *10,000 CFM.
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9,000 Exhaust air CFM, in this case *9000 CFM.
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And return air CFM, which in this case is 0.
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With this information the program provides a wealth of information
With this information the program provides a wealth of information. For example, (note to speaker, start at the OA entrance and walk through the air flow path) the OA is at 95F and 120 grains of moisture. As we go across the top portion of the energy wheel we drop to 81.2F and grains of moisture…a pretty significant drop. Next pass through the top part of the CDQ wheel and we see that the Dry Bulb temperature drops, from 81.1 to 77F while the grains of moisture went up from 79.1 to This happens because of evaporative cooling effect of transferring the water to the air by the CDQ wheel. Next we see we have picked up 1.3F of fan heat. And while we leave the cooling coil at 50F and grains of moisture as the air goes through the bottom part of the coil we see that it gets warmer and dryer with the leaving Dry Bulb temperature at 54.1F and the grains of moisture at 40.6. We can also see from some of the summary notes on the lower left of the slide that we saved 44 tons of cooling and 121 MBH of reheat energy. We can also see the Energy Wheel is pretty efficient with the ability to recover 76% of the Sensible Energy and 75% of the latent Energy. Finally if you click on the View PT Summary button…
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What pops up is the psychometric review of the entire unit’s performance.
This is a very effective new tool which can be found in the air handler custom toolbox.
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Optimized Controls *The last area of discussion is that of Optimized Controls.
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The Four “Money” Control Strategies
Fan Pressure Optimization Ventilation Reset Floor-by-Floor Building Pressurization Supply Air Reset These are four “Money” Control Strategies. Why the word, Money? If incorporated in the control specs, and held, these make it extremely difficult, and some would say almost impossible for the major control companies, let alone the trunk slammers. It is critical that our key consultants understand the benefits of these control strategies, get them written into their specs, and then hold them. This needs to be one of the major 2009 EWS AOP action items.
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Wireless Zone Sensors Auto-Commissioning Virtual Graphics
next generation VAV box control Three Capabilities That We Must Push Today!! Wireless Zone Sensors Auto-Commissioning Virtual Graphics Finally, let me talk about an additional four outstanding VAV Box control capabilities are a literally a generation ahead of our competitors. The three examples are: *Wireless Zone Sensors, *Auto-Commissioning, and Virtual Graphics. *Wireless sensors are working extremely well. They have a failure rate 10 time less than that of our wired sensors…and they are one of the best in the industry. But also this is where the entire industry will be going…with our first compete wireless offering being RT/VAV systems. We must lay claim to being leaders in wireless…period!! Finally, a typical wired sensor cost $150 to put a hole in the wall and run wire to it. Why would I not want to pay that $150 to ourselves by using wireless sensors? Plus this helps to minimize the electrical sub’s estimate (which can be inaccurate) and it helps to insure we get the sensor replacement parts business should anything fail years out.
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VAV Commissioning Report
Auto-Commissioning VAV Air System (Comm5) VAV Commissioning Report Site: Antletam 76.6 66.5 --- 324 72.4 / 71.0 No VAV3-05 73.2 63.2 339 73.3 / 73.9 VAV3-04 73.6 63.6 360 VAV3-03 73.1 63.1 116 73.7 / 73.0 VAV3-02 76.2 66.2 279 73.1 / 71.0 VAV3-01 83.4 73.4 451 70.6 / 71.0 FP VAV3-06 81.7 71.7 71.6 64.7 394 70.8 / 71.0 FP VAV3-05 78.6 68.6 68.5 61.6 718 74.6 / 73.9 FP VAV3-04 82.2 72.2 72.1 62.1 380 72.1 / 71.0 FP VAV3-03 HW Reheat Reheat Off Fan On Temp Fan Off Temp Air Flow Zone Temp / Zone Setpt Alarm Present 82.3 63.8 519 71.3 / 71.0 FP VAV3-02 Auto-Commissioning: As an industry we frequently don’t even do commissioning right the first time. What is needed is to do re- commissioning on an ongoing basis. We are very advanced in this area and we frequently don’t take advantage of it. This feature walks the VAV system through its sequence of operation and then provides a report which spells out whether there are any alarms, the zone setpoint vs. actual temperature, and the recorded airflow. Further, for fan powered boxes it runs the boxes through their sequence of operation and records the temperature both with the fan off and on and the heating coil to see the temperature both on and off. Most owners require an annual inspection for chillers to insure that this high energy consumer is working well and known problems are fixed. The auto-commissioning report is to the air-side what the chiller annual inspection report is to a chiller. Because the airside energy consumption is roughly equivalent to that of the chiller, a number of owners are asking for this level of proof performance and are writing it into service contracts. This is a prime example of how to design a high efficiency/low emissions systems that can truly provide documented sustainable performance. And imagine doing all of this remotely. This is an excellent of the type of things we can do for our customers via our Intelligent Service offering. Intelligent Service or “On StarTM for Buildings” is where the future is going and a wonderful way to demonstrate and differentiate our Systems Knowledge. Serving buildings from Cradle to Grave and back to Cradle is where we need to head and Intelligent Service is a key offering in helping us do that. Prime Example of What We Can Do Via Intelligent Service
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Virtual Graphics Importantly, can’t we use technology to make it easy for the operator to understand how to operate the system and monitor whether it is delivering this sustainable performance? The answer is yes. For example, here is a 3D graphics of a school. By simply clicking on the sections we can immediately see…
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Floor Plan what is going on in the various areas. The point is that if I’m looking a a gymnasium that it looks exactly like “my” gymnasium and…
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Chiller-Water VAV Systems
When I click on the air handlers and VAV boxes I want them to look like “my” units…
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Chiller-Water VAV Systems
and same is thing for the chiller plant. Making systems understandable is key to making sure the facility people truly understand their systems and that the systems are properly performing.
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AdaptiView™ Virtual Graphics on the Equipment
All of this with the end goal to make the unit controllers so easy that an operator can use the controls with “NO” instructions and with the ability to look, as if they had X-Ray vision, into the machine. Making these systems absolutely as easy to use as possible to use so they WILL be used on a long term, ongoing basis is the goal!! Making sure that Tracer systems are NEVER pulled off the wall because the operator simply did not understand how to use them…that is absolutely essential!! And one of the best ways to make sure that happens is using Virtual Graphics. The great news is this not only helps our customers but we are very competitive with our Santiago Chile created graphics. To give you an update on the latest on controls and our controls efforts let me turn it over to the next presenter.
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Trane Controls What to talk about???
Critical Valve Reset Points Lists BacNET TR1 Drives VAS PPS Swing Chiller Alarms MyTraneControls.Com Chiller-Tower Optimization Flexible Alarming Auto Calibration Digital Page Alarms Failure Reset Primary/Secondary ASHRAE Std 147 Report Graphical Trending Chilled Water Reset Electronic Tutorials Night Economizer Variable Primary Flow Rapid Power Failure Recovery ICE Mode Failure Recovery Variable Flow Compensation Make Available Base Chiller Flow Based Subtract Area Control LonTalk Ventilation Optimization Factory Training Heat Pump Control Variable Flow Process Start When Smitty asked me to talk about controls I had trouble figuring out what to talk about. After all we haven’t introduced anything NEW in a long time. [Click] So I struggled - nothing to talk about – nothing to talk about – too much to talk about – too much to talk about… We have SO much to talk about the biggest problem in knowing where to start. GraphICS TRAQ Dampers Industrial Options 3D Graphics Operator Override Enabled Setpoint Control 2D Graphics GeoThermal TOD Scheduling Soft Loading Fan Pressure Optimization Commissioning Reports StatiTrac V17 Demo Constant Volume AdaptiView Peak Chiller Demand Control Ventilation Auto Rotation Trend Logs Modbus SAT Reset Operator Manuals Adaptive Control Make Unavailable
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What to talk about??? Top 3 Control Sales Needs
“Our offering today is the “deepest” in HVAC system insight and capability” Mark Weldy Understand Trane systems’ full capabilities Get control of the control spec Work together Every once in a while you run into a quote that really encompasses what your trying to say. Here is one from Mark Weldy that I think does just that. It might be a little presumptuous of me to say but - Mark gets it. When it comes down to making system efficient, making systems sustainable and just flat making systems work, Trane has knowledge and controls capability untouched by any of our competition. [Click] The biggest problem YOU have is understanding what we have and using it to sell equipment, systems, solutions and service. So let talk about that.
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Top 3 Control Sales Needs 1. Know Trane full capabilities
Trane Resource Inventory Guide As they thought about this need Mark Weldy and Gene Shedivy commissioned Dave Uden’s Controls Applications Engineering group to create the “Trane Resource Inventory Guide.” This is a phenomenal piece of work. It is a one stop shop for information on Trane’s capabilities. Where would you find it – on the portal of course. And how would you find it on the portal. You would go to TCS Americas and then either to Product Portfolio and Controls or to EarthWise systems. Click on the link there and it will open the Trane Resource Inventory Guide spreadsheet.
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Trane systems full capabilities Trane Resource Inventory Guide
List of resources for: Chilled Water VAV System – Applied Tracker Systems Info there includes Description / Products Value Classification Competition Case Studies Presentations Training Seq of Op Points Lists Sales Tools
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Top 3 Control Sales Needs
Understand Trane systems’ full capabilities Get control of the control spec In order to WIN with controls you MUST get control of the control spec. What is the best evidence of that. [Click] Have you every seen or heard of this. Smitty talked about it in the EarthWise Seminar office reviews. JCI has created a library of control spec material to provide to engineers. Why? Because of the value it bring to Johnson! Fortunately we have a response – and its getting better.
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Top 3 Control Sales Needs 2. Get control of the control spec
Guide Specifications and Sequences of Operation Right below the Trane Inventory Resource Guide on the controls portal page is a link to Guide Specifications and Sequences of Operation.
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On that page you’ll find sequences of operation and points list for many types of air-side and water-side systems as well as EarthWise optimization strategies. Phil Lilja and Julio Londono at GCS are responsible for this great resource. But it gets better.
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Top 3 Control Sales Needs 2. Get control of the control spec
Pre-Packaged Solutions Right below the Guide Specifications link on the Controls portal page is a link to Pre-Packaged Solutions. Pre-Packaged Solutions take Guide Specs and sequences to the next step.
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Here is a print screen of some of the 150 air side systems that are in PPS today. The goal is by the end of the year to have the major types of chilled water systems also in PPS. Also the PPS team is working on a selection engine to make finding exactly the system you need faster and easier. [Click] When you pick one of these you get reward with Sequence verbiage, points list, flow diagrams and sales note. In addition in the Technician version is programming for the controller, operator graphics and commissioning sheets and GraphICS flow and controller detail drawings. Which leads me to my next
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2. Get control of the control spec Pre-Packaged Solutions
For New and Existing Building jobs Specification Information: Sequences of operation materials Generic input/output point lists Sales sketches offered in Acrobat and AutoCAD formats Generic product summaries Sales Notes Technician Information: Controller programming files Tracer Summit custom workstation graphics Commissioning sheets and application notes DEMO INSTEAD Demo instructions….
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2. Get control of the control spec Pre-Packaged Solutions
VAV AHU WITH HYDRONIC HEATING/COOLING AND PREHEAT AH0001
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2. Get control of the control spec Pre-Packaged Solutions
VAV AHU WITH HYDRONIC HEATING/COOLING AND PREHEAT AH0001
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2. Get control of the control spec Pre-Packaged Solutions
VAV AHU WITH HYDRONIC HEATING/COOLING AND PREHEAT AH0001
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Top 3 Control Sales Needs
Understand Trane systems’ full capabilities Get control of the control spec Work together You’ve heard it before right. The teamwork chant. The “One Trane mantra”. Well time to hear it again. If we work together we win – we all win. And there may be no better example of that than getting control of the control spec with Pre-packaged solutions.
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Remember PPS for Existing Building and Retrofit Work Too!
Work Together! Why? Remember PPS for Existing Building and Retrofit Work Too! Pre-Packaged Solutions bring advantages to EVERY step of the job process – Cradle to Grave. If we start a job with a PPS speced, it will frustrate competition, it will make Trane’s price more competitive, it will get us on and off the job faster and it will enable after the sale service. And its just as true for exisitng b
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Top 3 Control Sales Needs 3. Work Together
PPS Training Want to know more about Pre-Packaged Solutions. Check out the PPS training videos and other documents on the PPS Portal Site.
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Trane Controls Go talk about it!!!
Critical Valve Reset Points Lists BacNET TR1 Drives VAS PPS Swing Chiller Alarms MyTraneControls.Com Chiller-Tower Optimization Flexible Alarming Auto Calibration Digital Page Alarms Failure Reset Primary/Secondary ASHRAE Std 147 Report Graphical Trending Chilled Water Reset Electronic Tutorials Night Economizer Variable Primary Flow Rapid Power Failure Recovery ICE Mode Failure Recovery Variable Flow Compensation Make Available Base Chiller Flow Based Subtract Area Control LonTalk Ventilation Optimization Factory Training Heat Pump Control Variable Flow Process Start Ned/Al I have nothing else I can talk about so how about you take it from here… GraphICS TRAQ Dampers Industrial Options 3D Graphics Operator Override Enabled Setpoint Control 2D Graphics GeoThermal TOD Scheduling Soft Loading Fan Pressure Optimization Commissioning Reports StatiTrac V17 Demo Constant Volume AdaptiView Peak Chiller Demand Control Ventilation Auto Rotation Trend Logs Modbus SAT Reset Operator Manuals Adaptive Control Make Unavailable
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Creative Applications
Miscellaneous Musings Well, here I am again for my last piece. I would like to say how much I have enjoyed this seminar and talking with a lot of you between session. If there is anything I can do, or any additional materials I can send, please let me know. These don’t build in very logical manner, bit they fit into the material of the seminar.
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Miscellaneous Musings
Fan Pressure Optimization/Critical Zone Reset Pump Pressure Optimization Low temperature air distribution The importance of LEED® Let me reinforce some of the controls ideas that have come out. Lee and Smitty showed the theory and I want to share some experience we have had with them. [Read Slide]
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Fan Pressure Optimization /
Critical Zone Reset Let’s start with fan pressure optimization. I believe this is required by ASHRAE and by default may be a code requirement in some jurisdictions. I also think many of our controls competitors have a lot of trouble programming this, or they simply don't know what it is. Many of my engineers have written on the sequence and insist that it be demonstrated. It has a side benefit if literally avoiding almost all noise problems, at least those emanating from the VAV boxesselves. I have posted a sample sequence in the handout and on the web site of you need one.
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VAV System with DDC Controls
Duct Pressure Sensor Monitors temperature and cfm Just as a review, a typical DDC/VAV system ties the entire air system together. We monitor zone cfm and zone temperature. To cpntrol fan cfm, the classic approach is to place the static pressure sensor 2/3 the way down the duct and control to that. Often, the TAB contractor doesn’t know the actual static at this point, and arbitrarily sets it higher that it needs to be “just to be sure”. This results in the fan working harder and the VAV boxes choking down to reduce the airflow. This costs energy and often creates a noise problem. It’s like whipping your horse while reining him in. Communicating BAS Fan Speed or Inlet Vane Position
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VAV System with DDC Controls
Duct Pressure Sensor % Damper position If we were to create just enough static so that the air goes through the most demanding box or zone, we could locate the sensor in the unit fan discharge, like Intellipaks or perhaps unit controls on AHUs. We would then reset this value based on the damper position of the critical zone, or that with the most demand. The summit continuously monitors all the zones and can change the critical box. The potential for energy savings is significant, from one source in the range of 30 to 50%. The side benefit is the same sensor can be used for the high static safety. Another benefit is that keeping the static down keeps the noise level down and generally reduces the energy in the duct system. It might look like this: Communicating BAS Fan Speed or Inlet Vane Position
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Pressure Optimization Control Logic
The Tracer Summit monitors all the zones and discovers the unit with the most airflow requirement, Note that this is a % damper position. At design, we want the box to provide the exact cfm required with the box wide open. Another refinement is to also reduce or increase the discharge air temperature. We reduce the temperature when the critical zone reached it’s maximum cfm and the zone is starting to heat up. On the low side, we would increase the DAT when the static was reduced to a minimum. This will keep circulation up and reduce energy especially if you have reheats in the VAV boxes. © American Standard Inc 28
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Normal Operation Here is a screen shot of a building we did. I can call this up live and always use this to illustrate the feature when demonstrating Summit. (Could you do a last minute extemporaneous presentation to a customer? Do you have the ability to do one in your office or on your laptop? Are you working on specs with your good engineers?) ICS strategy is still our most powerful tool. Anyway, note that the supply air static is 1.6”, probably near the maximum, and the DAT is 53, with the Summit asking for With DX systems, the actual temperature is seldom what you ask for, but the PID controls average it over time.
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Reduced Load Here is the same screen at a different time. The static is at .7 and the DAT is at 53. The minimum has been reached and Summit is raising the discharge air temperature. I was showing this feature live one day and noticed that all the zones were cruising along about like this. One of the units was running at 3.5 inches of static. This didn't seem right. We dispatched a service tech and he found a page from the IOM lodged in the throat of the VAV box. The fan was trying its darndest to get the air through the VAV box. I didn’t look to see if the rogue paper was Intellipak or Varitrane related.
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Here is an Excellent Third Party Reference
There is a great article on Critical Zone Reset of Fan Pressure in the June 2007 Issue of the “ASHRAE Journal” I believe this article is posted on the web site
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. “Nevertheless, reset can generate fan energy supply savings on the order of 30% to 50% compared to fixed setpoints.” By Steven T. Taylor, P.E., Fellow ASHRAE ASHRAE Journal June 2007 Supply air fans on variable air volume (VAV) systems are typically controlled to maintain static pressure in the duct system at a given setpoint. Since 1999, ASHRAE Standard 90.1 has required that this setpoint be reset for systems with direct digital controls (DDC) at the zone level, specifically: Interesting Read that supports what we are saying. Note the claims for 30 to 50% savings in energy. This is huge. Setpoint Reset. For systems with direct digital control of individual zone boxes reporting to the central control panel, static pressure setpoint shall be reset based on the zone requiring the most pressure; i.e., the setpoint is reset lower until one zone damper is nearly wide open.
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Pump Pressure Optimization
You can do the same thing with the water side using valve position. If this slide looks familiar, Smitty talked about this before.
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Low Temperature Air Distribution
Reduced First Cost Reduced operating Cost Increased Comfort The Proverbial Holy Grail!! We have talked about low temperature and low flow waterside for years. The same thing can be said about using the same approach on the airside but with the added advantage of greater comfort. This is truly the holy grail. But why else would this be important to us at Trane? Well, because it takes cold water to make cold air, an we love cold water.
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Typical Objections What about condensation with low temp air?
What about cold air “dumping” from diffusers? What about adequate air motion in room? Whenever the subject comes up, the same objections come up over and over. Even in Arizona, we have humid periods of the year.
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Linear Slot Diffuser vs. Typical
Here is the famous coanda effect. The Trane diffusers actually work really well. The throat of the linear diffuser needs to be designed for high induction ratio. It actually draws room air, mixes, and sends normal air down to the space. A typical square diffuser can dump during periods of low airflow or when the air is too cold to mix. Diffuser selection is very critical.
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Parallel fan powered box
plenum air terminal mixing fan primary air Another idea is to use parallel fan powered VAV boxes. With Trane controllers the fan can be setup as the first stage of heat, OR to come on at a set primary air cfm, OR to run whenever the space is occupied. This will temper the low temperature air, and maintain a more constant circulation in the space, as well as increase the cfm/square foot that is reduced due to the lower design airflow. The plenum air is basically neutral. Many people mistake a lack of circulation as a lack of ventilation. Series boxes could also be used, but the parallel boxes gives more flexibility and all the benefits of the series approach. We did a job in my former life in downtown Boston. Cosentini in NYC designed the building with 49 degree air and fan powered boxes on the interior as well as the perimeter where we would expect to see them. I naively wondered what he had been thinking. It was pointed out that removing 2 courses of brick on each floor of a 36 story building can save millions of dollars. The smaller ductwork and low height boxes allowed this to happen. supply air
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One Unexpected Benefit For Hot and Humid Climates
When low temp air systems are designed for degree supply air, relative humidity in the space will typically be in the 35-40% range vs. a traditional system with 55 degree supply air providing relative humidity in the space of 55-60% This can be a huge boost to comfort in the indoor climate in the summer and an improvement to employee productivity You can read, but the gist of this is the comfort afforded by supplying dryer air.
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397440 Example of Low Temp Air Unit First Cost Savings-Chicago School
This is a real world example of a Chicago School that achieved significant first cost savings by changing to a low temperature air system. Note that the initial design was 55 deg air and total cfm was 397,440.
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Example of Low Temp Air Unit First Cost Savings-Chicago School
SYSTEM SENS ZONE GAINS ZONE COIL AHU SA OA %OA LOSS SENS LATENT LOAD LAT LAT CFM CFM Cafeteria 344,292 1,247,306 75,600 45.122 47 41247 14,400 0.35 Auditorium 292,863 289310 664,050 114,870 778920 45.272 47 21959 16410 0.75 Band/ Choir 189,109 440,997 77,430 518427 45.048 47 14583 8017 0.55 Fine Arts Rooms 196,028 647,233 90,380 737613 45.108 47 21403 8858 0.41 Administration 147,622 410,089 66,229 419,686 53.571 55 18986 4302 0.23 Ist Flr Gym Classes 132,203 322,833 57,181 380014 45.186 47 10676 5552 0.52 Gymnasium 398798 359352 45.463 47 39394 33120 0.84 2nd Flr Gym Classes 292,610 1,014,475 373,597 45.266 47 33547 19,410 0.58 AREA E To get the job in the budget, the school was redesigned using 47 degree air in all but two zones. The total cfm required dropped to 289,310. So what effect did this have on first cost? 362,369 926,737 109,943 45.089 47 30646 14139 0.46 West Ed Wing 324,801 819,437 97,008 916445 45.167 47 27098 11606 0.43 East Wing 320,153 900,273 148,146 45.167 47 29771 16886 0.57 Servery 75,090 41,208 116298 54.118 55 3476 2483 0.71 TOTAL 8,584,696 289310 152700
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Example of Low Temp Air Unit First Cost Savings-Chicago School
Reducing Air from 55 to 47 deg CFM decreased from 397,439 cfm to 289,309 cfm Actual Installed Cost for AHU Equipment was $2.90 per cfm. Cost Savings excluding sheet metal and labor was $313,577 on just AHUs ($.68/sq ft). These are the actual costs from the report. [Read Slide] Selfishly, you must be wondering why we would promote this system, we are actually reducing our bill of materials. One reason is that it has great potential to improve the design of the building. The other is that in order to get low temperature air, we need low temperature water, our favorite subject.
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Great Opportunity: Existing Buildings
We can often increase capacity in a building up to 20-40% by simply changing chillers and utilizing existing pumps, piping, towers, and air units. And reduce operating costs 15%- 40% It’s a system approach! Many buildings are suffering with higher internal gains from computers and other high energy equipment, or additional square footage is added to the building. By lowering the temperature and thus raising the delta temp, we can deliver more capacity through the same infrastructure.
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LEED® LEED is coming on like gangbusters. Municipalities and government agencies are requiring it, and now many developers are seeing reason to use it even on speculative office buildings.
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LEED –What are property managers, owners, developers saying?
Virtually all prospective tenants are asking if building is “LEED Certified” Tenants are willing to pay a higher rental fee in “LEED Certified” Buildings We need to do “Sustainable Audits” on our existing buildings to analyze potential for “LEED Existing Building” certification Tenants say “Our customers want to do business with “Green” companies” We may not be able to sell the building if it is not “LEED Certified” Here are some comments from property managers and developers. [Read Slide]
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So are owner’s willing to pay more to get their building “LEED Certified”?
25 Story office building Bill had commitment on SWUDs, and VAV Owner decided to go for LEED certification System was upgraded to chilled water with EarthWise design to get LEED Certification Owner spent an additional $1,500,000 ($2 / sq.ft.) to do this Trane bill of material almost doubled What about commission? But is it really happening? Ask my old friend (not really old, but long time) and student classmate Bill Faulkner about it [Read slide]
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It gets even better! 6 story office building Bill sold SWUDs and VAV
Submittal approved and equipment in production when owner decided to go for “LEED Certification” Owner delayed building opening for 6 months while system was redesigned to EarthWise Chilled Water System Owner paid $3,000,000 ( $20 / sq. ft.) in cancellation charges, change orders and upgrade fees to get the building certified! I think we are on to something here Here’s another one [Read Slide]
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“Are you going to be able to use our stuff on your schedules?”
Ask for the Order Don’t forget to ask for the order!! It’s most important when you work with engineers. Don’t assume “Are you going to be able to use our stuff on your schedules?” “I’d like to help you develop the details on this project, is this going to work for you?” Don’t forget to ask for the order. This doesn’t just pertain to contractors. This is actually more important with engineers. We need to make sure that we are going to end up in the right place if we are going to help him. Don’t assume. I always specifically ask something like “Are you going to be able to use our stuff on your schedules?”. or, “I’d like to help you develop the details on this project, is this going to work for you?” I then tell him why it’s important to be basis of design. Is it important to be basis of design? I think it doubles our chance of winning the order.
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Successful People don’t necessarily have the best of everything
They just make the best of everything they have.
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In Summary Sell the systems Make sure we use all the tricks we have
Embrace LEED Take the Accredited Professional test now Ask for the order Reinforce the slide bullet points
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Questions or Comments? Any questions for any of us?
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