Learning Outcomes Upon completion of this training one should be able to: Identify hydronic chilled water system applications. Define the difference between.

Learning Outcomes Upon completion of this training one should be able to: Identify hydronic chilled water system applications. Define the difference between single-pump and multiple-pump design. Understand parallel pump design and operation. Explain the basic design principles of Domestic HW Recirculation Systems. Upon completion of this training one should be able to: 1) Identify the influence of codes on pump & hydronic design, 2) Understand HVAC loads & their impact on equipment selection, 3) Compare hydronic HVAC system types & pipe configurations, 4) Determine appropriate applications for the Manga3 pump, 5) Utilize life cycle cost economics to justify the use of the Magna3 in both new and renovated systems 1 1

Medical Office Building
As we discussed earlier, we have created a prototype Medical Center with three types of building which will contain a variety of hydronic systems which can be served with Variable Speed type pumps. We just reviewed a simple one-story building. 80 percent of all buildings constructed in the US are 1 to 2 story buildings. Now we will discuss a larger, more complex facility such as a Medical Office building. 2

Medical Office Building
Occupancy – 400 persons 8 a.m. – 5 p.m. Monday - Friday Building Characteristics Three stories 40,000 square feet (200’ x 200’) per floor Standard construction Our Medical Office Building example is a multiple story, 40,000 square foot facility utilizing “standard construction” techniques. The occupation is for a maximum of 400 persons and includes both heating and cooling loads, 5 days a week, 8am – 5pm. We will address the design with stand alone heating and cooling hydronic systems. 3

Office Application This is sectional view of the potential systems in a Medical Office building which can be served by Variable Speed type pumps. 4

Office Application This is an sectional view of the potential systems in a Medical Office building which can be served by Variable Speed type pumps. 5

Office Application This is an sectional view of the potential systems in a Medical Office building which can be served by Variable Speed type pumps. 6

Hot Water Systems Primary Pumps Secondary Pumps Tertiary Pumps
Heat Recovery Pumps Air Handlers Fan Coils Radiant Floor Convection Units Filter Pumps Depicted in the Medical Office Building sectional view are hydronic applications which use Variable Speed type pumps, such as: Primary Pumps Secondary Pumps Tertiary Pumps Heat Recovery Pumps Air Handlers Fan Coils Radiant Floor Convection units Filter Pumps 7

Hot Water Systems P5 P5 P3 P3 P3 P4 P2 P1 P6 Type of Pumps P1 Primary
Fan Coils Radiators In-floor HWR P5 P5 CW Air Handler with Heat Recovery HW P3 P3 P3 P4 P2 Heat Exchanger P1 Type of Pumps P1 Primary P2 Secondary P3 Tertiary P4 Domestic HW P5 Heat Recovery P6 Filter Boiler 1 Boiler 2 A single line diagram incorporating the hot water applications are shown here. A single line diagram is a very useful tool to help analyze systems and potential piping problems. P6 Filter System 8

VS/VV Hot Water Systems
Secondary Pumps Supply ΔP Sensor VSP2* VSP1* P2* P1* VS Pumps and Controls Boiler 1* Boiler 2* This is the hot water, primary-secondary two-pipe direct return system we have been featuring: What are its advantages and disadvantages? Lower return water temperatures. Minimizes flow to coils. Decreases secondary flow. Reduces boilers on line. Boiler performance is increased. In addition: Ease of System Operation. Energy Savings. Preferred Piping Method. We will be introducing Chilled Water applications in the Medical Office Building. They will be very similar to the HW systems, but they have a few distinct differences. Return *Sequenced 9

Chilled Water Applications
Primary Pumps Secondary Pumps Condenser Water Pumps Fan Coils VAV Air Handlers Chilled Beams Larger building such as the Medical Office Building now can utilize more sophisticated hydronic cooling systems. The introduction of hydronic cooling systems greatly increases the number of pumping opportunities. Common pumping applications can include: Primary Pumps Secondary Pumps Condenser Water Pumps Fan Coils VAV Air Handlers Chilled Beams 10

Chilled Water Applications
Beams Fan Coils Radiant Type of Pumps P1 Primary P2 Secondary P3 Tertiary P4 Condenser Water P5 Air Handlers P6 Filter P3 P3 P3 Air Handlers P5 P2 Cooling Tower Chiller Chiller Here is the single line diagram of typical chilled water pump applications. Again, it is a very useful tool for system application analysis. When looking at retrofit opportunities, this should be one of the very first steps. What are some of the new components we are introducing: Chillers – replace boilers Air Handlers – much larger than VAV boxes, but work in a similar manner Cooling Towers – once again, similar to those in heat pump systems, but larger and often open loop design, rather than closed circuit. Chilled Beams – still a radiant device, but temperature concerns looms due to the potential of condensation. P4 Common Pipe Condenser Water P1 P1 Filter System P6 Expansion Tank Air Separator 11

CHW System Differences
Pumps are typically 3-4 times larger Condensation concerns Air separator location Primary pump location Open loop system piping Chilled water systems differences A typical hot water heating system operates on a ΔT at about 40°F. Chilled water systems operate an a much more narrow range at about 12-15°F. How does this impact pump selection? Do the math! HP = F x Hd x SpGR/ CHW pumps are typically 3 to 4 times larger than their HW counterparts. A lot more variable speed opportunity in CHW applications. Because of humidity (latent heat) concerns, control is also more critical. Air separators belong in the warmest water location, so they are located on the return side of the system. We teach to pump out of a boiler and into a chiller. I explain this in depth later. Also cooling towers are typically open loop which introduces new operating and piping concerns which we will also detail later.

Parallel Pumping Single pumps versus multiple pumps Advantages
Common configurations As we get into larger systems, analysis will show us that multiple pumps provide advantages over single pumps…remember more pumps is always better…right? Let’s look at some obvious advantages of multiple pumps, then we will explore common piping configurations for multiple pumps. 13

Single vs. Multiple Pump Comparison
Single Pump Design Higher HP No redundancy Less piping Less maintenance Less complicated Higher operating cost Multiple Pump Design Lower HP Redundancy More piping More maintenance More complicated Lower operating cost There are many advantages of multiple pump design: Single Pump Design Higher HP. No redundancy. Less piping. Less maintenance. Less complicated. Higher operating cost. Multiple Pump Design Lower HP. Redundancy. More piping. More maintenance. More complicated. Lower operating cost. A significant take-away here is the smaller sized pumps are the RIGHT sized pump most of the time, and operate for longer periods. 14

Parallel Pumping Common Configurations – Closed loop systems
(2) 50% Duty Pump 100% Duty Pump 50% Duty Pump 100% Standby Pump 50% Duty Pump Here a couple of common configurations for multiple pumps in closed loop applications: Please note here the difference here between parallel pump DESIGN and parallel pump OPERATION. 100% with 100% standby is the most common. This configuration ensures redundancy in case of a pump failure. Critical applications often follow this practice. Disadvantage of this configuration is first cost and a high horsepower is always on line. In this case the pumps are piped in parallel, but operation of more than one at a time is NEVER expected. Electrical wiring is not designed for more than one in operation. In less critical applications a good alternative is two pumps selected at 50% of design. Pumps are typically less expensive and less expensive to operate. Designers can get very creative with this configuration as I will show you later. The remaining examples the pumps are parallel design AND for parallel operation. The pumps and electrical wiring are designed for more than one pump to operate at any given time. Critical applications looking for redundancy, yet optimized performance can be addressed with 50% duty pumps. Costs may be less than 2 100% duty pumps, provides redundancy, and allows for peak performance. A variation of this configuration can be 33% (or greater) to reduce first cost. Let’s take a closer look at parallel pumping. (1) 50% Standby Pump 15

Parallel Pumping Parallel Pumps - What? 1000 GPM @ 100 Ft 2000 GPM
Here is the single line diagram for pumps in parallel. Note that check valves are critical for this design. Without check valves, if one pump was on and the second pump was off, without a check valve, the activated pump would flow backwards through the second pump, creating a short circuit…and no flow! 16

Parallel Pumping Parallel Pumps - Why?
Parallel pumping provides additive flow at the same point of head. Why do we want parallel pumps? We can double the flow in the pipe and the same head resulting in an energy saving potential. 17

Single Pump Curve Head Flow Pump Curve Point of Selection
This is how parallel pump curves are manually created. A pump is selected for 50% of the design flow at 100% of the design head. A pump curve is then plotted. Flow 18

Parallel Pump Curve Head Flow Single Pump Curve Parallel Pump Curve
Flow 1, Pump 1 Flow 1, Pump 2 Single Pump Curve Point of Selection Duty Point Parallel Pump Curve The next step is to draw a horizontal line through the duty point and make a second point at exactly double the original flow. This is done several times to create a composite pump curve. The resultant pump curve meets the flow and head criteria for the design conditions. 19

Parallel Pumping Parallel Pumps - Advantages Smaller pumps
Smaller motors Lower operating cost Standby options Right size pump operating more often What are the advantages of parallel pumps? Parallel Pumps - Advantages Smaller pumps. Smaller motors. Lower operating cost. Standby options. Right size pump operating more often…since pumps are ALWAYS over-sized, it means that the right size pump is operating more often. More Pumps, too! 20

Parallel Pumping Getting more out of your pump! % Full Load HP % Flow
90 80 70 60 50 40 30 20 10 100 % Full Load HP % Flow Parallel C/S 2 Pumps Single C/S Single Parallel C/S When designing pumps in parallel, consider getting the most possible out of the pump, based on the motor provided with that pump. Typically a properly selected 50% duty pump can run out on its curve to more than 75% of its rated duty point. The longer the 50% pump can operate, the less expensive it will be to operate. You can see from our Chicago load profile example that a single pump sized at 50% of the peak flow can actually handle the system needs, 65% or less of full flow, for nearly the entire year! Which is more efficient…a smaller pump operating at or near 100% flow or a pump twice the size operating a part flow? Talk about energy savings, 21

Parallel Pumping Operation Beyond Selection Point
Pump 1 & 2 selection: ft Pump 1 selection: ft Pump 1 operation: ft Operation beyond design point provides a distinct advantage, if done properly. Here is a graphic example of the impact of the proper selection of pumps in parallel. Although the pump is selected for feet, the “50%” pump can run out on its curve to 820 gpm…a 64% advantage. The 15 hp pump can operate nearly continuously in lieu of a 25 hp “duty” pump. System Curve 22

Parallel Pumping Review
Selection Criteria Select pumps for 50% of total flow (500 gpm, each) Make sure each pump can cross system curve Parallel Pump Advantage Pump runs out to 820 gpm Operate one pump for ≥ 80% of the time Save operational cost! Let’s review Parallel Pump selection and advantages Selection criteria Select pumps for 50% of total flow (example: 500 gpm, ea) Make sure each pump can cross system curve Advantages Pump runs out beyond 500gpm to 820 gpm Operate one pump for up to 80% of the time Save operational cost 23

Parallel Pumping Cautions
Improper parallel pump selection Pumps too small End of curve Unequal sized pumps Erratic operation Simple, right? Not that easy, cautions have to be made. What cautions should be made when selecting pumps in parallel: Parallel Pumps - Cautions What is the impact of an improper parallel pump selection? An improper pump matchup can result in End of curve. Erratic operation 24

Parallel Pumping Caution
150 120 90 60 30 Pump 1 selection: ft Pump 1& 2 selection: ft Pump 1, 2, &3 selection: ft System Curve Head (ft) Pump 1 Pump 2 Pump 3 End of Curve Here is a example of a pump selection that should be avoided. Design flow is feet. 3 parallel pumps are selected for feet, each. When analyzing the composite curve, it is very evident the lead pump does not cross the system curve…what does that mean? Cavitation can occur. Cavitation results in over heating of the fluid; undue stress on the pump bearings and shaft; noise; and premature impeller failure. Designers should avoid this selection. If this selection exists in the field and the noted symptoms are occurring, steps can be made to avoid some of the problems. If pumps are constant speed, always run at least two pumps all of the time. This will treat the symptoms…not cure the problem. If pumps are equipped with variable speed drives and a programmable controller, the maximum operating speed of the pump prior to cavitation (point where the curve still crossed the system curve) can be programmed. At this point a second pump should be brought on line. Flow (gpm) 25

Unequal Size Pump Selection
Parallel Pump Caution Unequal Size Pump Selection Best design practice is to select identical pumps for parallel operation. When pump are dissimilar, the composite curve is not smooth. This drawing illustrates when two unequal pumps are operated in parallel. This condition is know as a “knee” in the curve. A drastic change in operational conditions exist, resulting in erratic operation. As the demand changes and valves open or close, this condition can result the larger pump holding the smaller pump’s check valve closed, creating cavitation and premature impeller, seal or bearing failure. 26

Sequencing Parallel Pumps
Pump sequencing methods: Head Differential Head Temperature Flow Current sensing How are pumps operated in parallel? How are they properly sequenced or staged. Staging can be done in many ways such as: Head Differential Head Temperature Flow Current sensing It is a matter of equipment and programming knowledge. In closed loop systems, differential head is most common, but flow or current sensing staging can be achieved. In some cases a combination of multiple sensing points can be used. “Smart pumps” like a Magna3 can be factory programmed for optimum results. 27

Sequencing Parallel Pumps
40 35 30 25 20 15 10 5 P1&2 Duty point P1 Head (ft) Staging point With this constant speed pump selection, the lead pump (P1) operates along its impeller curve until pump reaches the system resistance curve. At this point, max flow, minimum head, or maximum current draw occurs and a second pump (P2) is staged on. The pumps now follow the composite pump curve as the valves continue to modulate. The “tricky” part is knowing when to “de-stage” the extra pump. You can see the curve becomes rather flat at the top. It can be difficult to know when to turn off P2. Some unsophisticated systems just use a timer to turn off the pump and let the system sensor dictate when it should be turned on again. Other ways include flow sensing points of operation, or current readings, or even differential pressure settings. Flow (gpm) 28

Parallel Pumping Parallel pumps - Operation How many can you add?
Practical limit – 6 pumps Another question can arise…how many pumps are practical to operate in parallel? Individual pump curves can vary, but again, best design practice usually puts a limit of 6 pumps in parallel. 29

Maximum Number of Parallel Pumps
As you can see in this example, each additional pump in parallel adds a smaller and smaller increment of flow and head. First cost becomes prohibitive and performance is not enhanced. It makes more sense to use larger pumps. Another concern is “End of Curve.” The greater the number of pumps in parallel , End of Curve condition becomes more common. P2 P3 P4 P5 P6 P7 P1 30

Parallel VS Operation How are variable speed pumps sequenced?
Point E Point D Point C Point B Point A How are variable speed pumps sequenced? Once again, differential pressure is the most common method, but current, or flow may be an option. The lead pump is turned on and the control curve is followed until it can no longer meet system demands (Point A). At this point a second pump is turned on at full speed. Since the resultant flow and head produced to greater that what the system need, the differential pressure sensor will signal the drive to slow down, meeting system demands. As system demands continues to increase, the equally operating pumps will ride the control curve until they can no longer meet system demands (Point B). The next pump will then be turned on and operation proceeds as before (Point C). As with constant speed pumps, the “tricky” issue is de-staging. A proper algorithm must be created to accomplish this energy savings decision. Typically the de-stage points will be at or near Points D&E. 31 31

VS/VV Pumping Add: Variable frequency drive (VFD)
Programmable logic controller (PLC) Differential pressure sensors (∆P) Direct digital controls (DDC) Save operating cost versus CS/CV system! To convert the system to variable speed, variable volume we must add: variable frequency drive(s). programmable controller. differential pressure sensors. direct digital controls. And save money! Typically a vs/vv pumping system will cost much less to operate. 32

VS/VV Pump Energy Consumption
CS/CV CS/VV VS/VV The addition of properly controlled variable speed drives on the secondary pumps will cost: Less than 75% of a cs/cv system! Less than 50% of a cs/vv system! 33

Advanced Control Methods
Controlling VS Pumps Traditional methods Previously discussed Constant flow Pressure ΔP near the pump Remote ΔP Multiple ΔP Temperature So we discussed the traditional way it has been done with: Constant flow Pressure ΔP near the pump Remote ΔP Multiple ΔP Temperature are good ways, but the only way? 34

Intelligent Control Optimized solution not only for the pumps, but for the total system conditions Uncontrolled (constant volume) curve Constant pressure Proportional pressure (calculated) Proportional pressure (measured) Temperature control Intelligent control sequencing: Optimized solution not only for the pumps, but for the total system. Let’s look at performance curves for: Uncontrolled (Constant flow) curve. Constant pressure. Proportional pressure (calculated). Proportional pressure (measured). Temperature control. ...so you can decide the best way to control the pump. 35

Intellegent Control Get Additional Energy Savings Uncontrolled
Constant pressure Proportional pressure (calculated) Proportional pressure (measured) Temperature control 100 80 60 40 20 Flow in % Effect in % 1. 2. 3. 4. 5. In systems with variable flow it is possible to get significant energy savings, the total saving is depending on the control mode. The graphic shows the savings for the different control modes. The curve on the right shows the impact of the types of control mode. Please note that the vertical curve indicates the Effect of the different control stategies. Don’t be confused thinking Effect is an abbreviation for Effeciency, like I did at first. The Effect of the various control programs result in lower energy consumption at lower flows. Uncontrolled offers the least energy savings. Essentially the pump rides the impeller curve. The addition of Constant Pressure Control provides a significant reduction of energy use. Constant pressure control is most often used for closed loop, pressure booster applications. Proportional Pressure Control (calculated) is used for closed loop applications. It is not quite as effective as Proportional Pressure Control (measured), but does not require the first and installation cost of external sensors. Temperature Control, either single temperature or differential temperature, can utilized in primary pumping applications to minimize pumping through the boiler. Note that the Effect Curves are greater than 100% for the control methods... why? The VFD has an effeciency of less than 100%, so at full speed, the ”Uncontrolled” (driveless) pump is more effecient that a pump controlled with a VFD. Q 100% 25% H 36

Life Cycle Costing Optimized operation cost often means LOWER ENERGY COST An effective way of checking the profitability of the pump system is to use Life Cycle Cost analysis. This will show not only the ”energy cost” but all costs related to the pump system. The result of the analysis can show the pay-back period of a variable speed system compared with a constant speed system. Life Cycle Costing is a very important tool to analyze the impact of energy consuming products. In a later session we will go through the details in analyzing the Life Cycle Costing process. 37

Domestic Hot Water (DHW) Recirculation Systems
A final system design to explore using variable speed in-line pumps is Domestic Hot Water Recirculation. 38

DHW Recirculation Systems
Three types of DHW systems: Self-regulating heat trace system Point of use water heater Recirculating systems There are three types of DHW system designs which can deliver hot water to the point of use providing low water waste: Self-regulating heat trace system Point of use water heater Re-circulating systems We will further discuss Recirculating Systems. 39

Provide hot water at the furthest fixture
DHW Recirculation Systems Provide hot water at the furthest fixture without having to drain the standing cold water from the piping. The objective is to provide nearly instantaneous hot water supply to all fixtures all of the time without having to drain the standing water in the pipe. This tends to be more of an environmental concern that an energy saving objective. 40

Use ASPE Domestic Water Heating Design Manual as a design reference The best reference for DHW Design is to use the ASPE DHW Design Manual as a design reference. 41

Last Fixture Cold Water In Hot Water Out Flow Hot Water Heater This is a schematic of a domestic hot water re-circulation system. 42

Design Criteria: Determine wait time Calculate heat loss Calculate piping pressure drop Determine control method Select pump Check local codes Design Criteria are: Determine wait time Calculate heat loss Calculate piping pressure drop Determine control method Select pump Check local codes 43

More immediate desired hot water temperature at the tap Decrease Legionnaire concerns Reduce water consumption Hot water re-circulating pump controls are addressed in the energy codes because the operation of the pump when there is not demand or need is a waste of energy. The energy codes do not ban the use the use of re-circulating pumps because their implementation is important to good building operation besides increased satisfaction of the owner due to more immediate hot water at the tap. The use of a recirculation pump can ultimately increase occupant safety and reduce water consumption with only minimal increase in energy use. The threat of Legionnaire is real – the actual numbers of people affected each year is difficult to document since it is often misdiagnosed as pneumonia. One way to minimize building occupant exposure is to eliminate standing warm water where the bacteria can colonize through the use of a re-circulating pump. The use of a recirculation pump will result in decreased water consumption because the user will not have to wait for the water line to empty of cold water. The amount of energy consumed by the pump will be offset by the energy required to produce the hot water not only for the demand at the tap but also to refill the hot water line to get to the consumption point. This hot water in the line will then become cold and have to replaced again the next time there is a need for hot water. 44 44

No specific national code requirements – some local codes >100’ length rule is no longer valid since both energy and water use have become important Length of time has increased due to low flow fixtures Older faucets: 2.2 GPM (prior to 1992) Low flow faucet: 0.5 GPM ½” pipe: 0.01 gallons/foot Run time to empty 100’ length of ½” pipe – Old faucet: 27 seconds Low flow faucet: 2 minutes A hot water re-circulating pump is not required per any national codes but may be by local codes enforced by a jurisdiction. In the past many designer used the rule to apply a re-circulating pump when the hot water pipe length exceed 100’. This rule is not longer valid since both water consumption and energy use have become a priority. The 100’ foot rule was established with only the concern of occupant satisfaction in mind and ensuring the hot water at the tap in less than 30 seconds. The reason this rule has changed is the implementation of low flow plumbing fixtures. Consider that older faucets had a flow rate of 2.2 GPM compared to today’s low flow faucet of 0.5 GPM. If we make the assumption both fixtures are supplied by a 1/2” copper pipe holding 0.01 gallons of water per foot the run time required to get hot water to the faucet increases from 27 seconds to 120 seconds. 45 45

DHW Recirculation System
Consider the delay time for HW 0-10 seconds for public fixtures in office buildings 11-30 seconds marginal but acceptable >31 seconds unacceptable (significant waste of water and energy) Max. distance ~25’ between the HW loop & the fixture Calculated length based on pipe size and distance 2 minutes is clearly an unacceptable wait time – none of use would wait, we would simply assume hot water was not available and wash our hands in cold water. Acceptable time delay for hot water is 0-10 seconds for public fixtures in office buildings with 30 seconds being the limit. Anything greater 31 seconds is considered unacceptable because of the significant waste of water and energy as well as lack of occupant satisfaction. The new rule should be to limit the pipe length between the HW loop and the fixture to 25’ for today’s new low flow fixtures. This can be more accurately calculated for a specific application if the pipe size and distance is known. 46 46

Control Options Manual control Thermostatic aqua-stat Time clock Local Code Considerations Control Options Manual control Thermostatic aqua-stat Time clock Energy Codes ? 47

Type of pumps Because of the corrosiveness of hot water systems the pumps should be all bronze or stainless steel Low-lead bronze requirement in CA, Federal Government Make sure the pumps pressure rating is higher than the relief valve Type of pumps Because of the corrosiveness of hot water systems the pumps should be all bronze or stainless steel. The State of California instituted a code referred to as AB In this code, all bronze components in a DW system must be of low-lead manufacture. Other states are pursuing the similar restrictions. Manufacturers may follow Standard NFS61 to achieve this target. Standard NFS61 is somewhat more restrictive than AB The Federal Government is also pursuing this directive. Make sure the pumps pressure rating is higher than the relief valve 48

Type of pumps An inappropriate DHW recirculation system can have serious repercussions for the operation of the water heater and the sizing of the system Type of pumps An inappropriate hot water recirculation system can have serious repercussions for the operation of the water heater and the sizing of the system. 49

Select pump In order to minimize energy cost associated with the perfect pump for this application is a variable speed in-line pump. A vs in-line matches the flow requirement without over pumping. 50

Learning Outcomes Upon completion of this training one should be able to: Identify hydronic chilled water system applications. Define the difference between.

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Learning Outcomes Upon completion of this training one should be able to: Identify hydronic chilled water system applications. Define the difference between.

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