Slide 1. Slide 2. Slide 3 288,817,200,000. Thank you for attending the session on Hot Water Re-Circulation.

Transcription

1 Slide 1 Thank you for attending the session on Hot Water Re-Circulation. Hot Water Re-Circulation National Conference Center Lansdowne, VA March 25 th & 26 th, 2010 Slide 2 AGENDA Water Waste Statistics Intro to Hot Water Recirculation Pump Fundamentals Sizing & Selection Troubleshooting Slide 3 288,817,200,000 This is the average number of gallons that are wasted in a year in the United States.

2 Slide 4 Do You Know... ASPE, the American Society of Plumbing Engineers, recommends A maximum wait of 10 seconds from the time a faucet is turned on until hot water reaches the faucet seconds is marginally acceptable, depending on the application This information is from ASPE s Domestic Hot Water and Heating Manual. Slide 5 How much water are we wasting An average home over 2000 square feet (home sizes have grown from 1,440/sq in 1970 to over 2,200/sq in The distance between the hot water tank and the faucet continues to increase) will have 125 feet of 3/4 inch pipe. A Type L copper 3/4 inch pipe 125 feet long holds 3.14 gallons of water. 10 draws per day will waste 31 gallons waiting for hot water. The waste of water in 1 year would be 11,461 gallons. If all the homes over 2000 square feet are waiting for hot water, they would waste 288,817,200,000 gallons. Slide 6

3 Slide 7 Did you know.. *****FACT***** An estimated 36 of 50 states are facing water shortage problems. The solution to the hot-water waste must offer a convenient product that is easy to use and has a short pay-back time 7 Slide 8 Hot Water Recirculation How HWR Works? Hot water recirculation helps you save water by keeping hot water in the recirculation line. Slide 9 Hot Water Recirculation UP Series - New Home A Grundfos Comfort Pump can save more energy and water by utilizing a timer.

4 Slide 10 Typical Installation Note the correction position of the pump is on the return. Slide 11 > Fundamentals: Pump Terms Volute: (pump body) encloses the impeller & the pumped fluid, & provides a channel to get it into the discharge piping Impeller: adds energy to the fluid & moves it to wherever it is needed Impeller Motor: is the driver it spins the impeller Volute Motor Slide 12 Impeller Direction of Rotation It is very important that the impeller turn in the right direction. The vanes need to fling the water, rather than cup: it. Explain that as the impellers rotate, they hurl water outward and up out of the pump. This naturally creates a vacuum at the eye of the impeller, which allows in more water. Otherwise, the pump can only develop about 70% of its designed pressure. And it can damage the pump and motor

5 Slide 13 Centrifugal force Remember when you were a child and went to the playground and got on the spinning wheel When you were standing in the middle you could stand for ever and ever no matter how fast the wheel was turning YOU WERE KING But when you were at the end of the wheel and it began to spin you could only hold on for so long the faster the wheel spun the harder it was to hang on and is was not long that you were thrown off THAT S Centrifugal force Slide 14 Slide 15 How are you using the pump in the house? Open system: the water is open to oxygen/outside air Closed system: the water is contained and not open to outside air One must determine if the project is to heat the home or to provide hot water recirculation.

6 Slide 16 Open or Closed? I have radiators that provide heat to my house. The heat source is a hot water boiler. I have a hot water recirculation line that circulates water from my water heater to my bathroom and back to my water heater. The first situation is a closed system and the second is an open system. Slide 17 Impact to Pump Choice In closed system where there is no air coming in contact with the water, we can use Cast Iron. In open systems we must use a material that will not rust or corrode away, like Bronze or Stainless steel. When choosing a pump, it is important to think about whether it is for a closed or open system. Pumps come in different materials: cast iron, bronze, and stainless steel. For a closed system where there is no oxygen to impact the pipes, cast iron can be used. In an open system where the system will be exposed to oxygen, bronze or stainless steel should be the choice. For hot water recirculation, we will have an open system. Slide 18 Residential Product Selection UP/UPS Series Circulators in Bronze and Stainless Steel UP Series Circulators in Bronze Bronze circulators are available with optional timer and aquastat controls to offer greater control of the HWR system. Bronze units can be ordered with flange, or sweat fittings. The bronze unit can also be ordered with a check valve integrated into a union tail piece. The piping connection is then sweat fitted to the system. UP Series Circulators in Stainless Steel Stainless steel circulators are available with optional timer and aquastat controls to offer greater control of the HWR system. Stainless steel units can be ordered with union or flange fittings.

7 Slide 19 Hot Water Recirculation Comfort System Retrofit You can still improve the energy savings and water savings in an existing home, you just need a Comfort System for the retrofit. Slide 20 Direction Of Water flow This is an example of a properly installed pump for a retrofit. Slide 21 This is the Thermal Bypass Valve that makes the system work. Note that in some homes you may need to install rigid risers and cutting the valve into the risers with compression fittings. Thermal Bypass Valve Pg 15

8 Slide 22 Tankless water heaters Tankless Valve Cold In Hot out Cold water in Comfort pump going on hot side to house A Small 2-4 gallon hot water tank Hot water to valve Slide 23 Slide 24

9 Slide 25 Highlights of Hot Water Recirculation Systems Convenient (not like low flow showers or low flush toilets) The Comfort of Instant Hot Water Water Conservation Distinguishes Home from Others Slide 26 How to Select a Pump for Domestic Hot Water Recirculation This is our path to selecting the correct circulator. The first box is empty because it deals with calculating a heat load. It s not relative to what we re doing here so we begin with determining our flow. Slide 27 How do you determine GPM? Note that this is the best case scenario, but as we move on we ll give you a rule of thumb to use when sizing domestic HWR systems. (Rule of Thumb listed below) Determine the water volume of the hot water piping, desired time to purge the standing water from the pipe, and the flow rate needed to keep the velocity below 4 feet/sec Easy way is 10,000btu =1gallon (1 GPM can carry 10,000BTU s) BTU load 8.3 x 60 (seconds) x 20 (Delta T) = flow rate 80,000 btu / 10,000 Factor= 8gpm Why do we want the velocity less than 4 feet/second? When it gets above that there may be noise in the pipes, above 8 feet/second can cause pin-holes to develop in the elbows and joints of copper tubing.

10 Slide 28 Determine GPM Heat Loss chart for Copper Tube (Pg. 58 HVAC Tech Guide) 100 ft of ¾ Supply + 100ft of ½ Return: ¾ Pipe (120 deg.)=? (17) 17 x 100= 1700 BTU + ½ Pipe (120 deg.) =? (13) 13 x 100 = 1300 BTU 1300 BTU BTU = 3000 BTU 3000 BTU / 10,000 BTU =.3 GPM Slide 29 How do you select the proper sized pipe? Golden Rule of Pipe Selection Velocity through the pipe network should not exceed 4 feet/second See page 39 in the Technical Book Slide 30 Select Pipe Pg. 39 HVAC Tech Guide How many GPM can you put thru: ½ Pipe ¾ Pipe 1 Pipe Velocity through the pipe network should not exceed 4 feet/second Smaller pipe saves $$ up front..but.cost more $$ for pump and cost to run pump.

11 Slide 31 How do you determine head? Head is calculated by multiplying the length of the hot water main, the return line, and the fittings, by the friction loss values. Rule of thumb add 20% for fitting friction loss Length of pipe and fittings The friction loss is small except for spring loaded check valves. As high as 9 ft head Slide 32 Determine Head Determining Friction Loss (pg. 39 of HVAC Tech guide): 100 ft of ¾ Supply (Copper Type L) Flow 1 GPM= ft of ½ Return (Copper Type L) Flow 1 GPM = 2.45 Total: = 2.89 FL +.58 (20% Fittings) = 3.47 TDH Slide 33 System Parameters: Main line: 3/4 type L copper 20 std. 90 s 10 Std. T s 100 feet of pipe Return line: 1/2 type L copper 10 std. 90 s 100 feet of pipe Friction Loss Example. Floor Plan: 55 6 x 25 Hot Water Main: 50 feet of ¾ Type L Copper Return Line: 50 feet of ½ Type L Copper

12 Slide 34 Solution for Problem One Main Line Desc of Ftgs Qty of Ftgs Value Equiv of Pipe Ea Equiv Lgth Std 90 Elbows 10 X 2.3 = 23 Std Tee 5 X 1.4 = 7 Ftgs Equiv Lgth Actual Pipe Lgth Total Equiv Lgth = 130 Total Equiv Lgth Friction Factor Total Friction Loss 130/100 X.44 = Slide 35 Solution for Problem One Return Line Desc of Ftgs Qty of Ftgs Value Equiv of Pipe Ea Equiv Lgth Std 90 Elbows 10 X 1.6 = 16 Check Valve X = Ftgs Equiv Lgth Actual Pipe Lgth Total Equiv Lgth = 116 Total Equiv Lgth Friction Factor Total Friction Loss 116/100 X 2.45 = Slide 36 Solution for Problem One Total Head Loss of System Main Line + Return Line 3.41

13 Slide 37 Where do you find the pump curves to use in selecting the pump? Picking the right pump save you $$$$$$$ Slide 38 The System Curve Shut-off / Dead-head Operating Point Run-Out Pg 7 Slide 39 Pick a Pump UP Product Guide Look at head first.

14 Slide 40 Review Slide 41 Outline of Problem Two Objective: Select the proper hot water recirculation pump for the given home Tools: Product Information Guides (Pump Curves) Technical Data Book (Friction Loss Tables) Information: Information needed to solve problem located in System Parameters Floor Plan: 55 6 x 25 Hot Water Main: 50 feet of ¾ Type L Copper Return Line: 50 feet of ½ Type L Copper Slide 42 Outline of Problem Two System Parameters: Supply line: 3/4 type L copper 200 feet of pipe Return line: 1/2 type L copper 200 feet of pipe The water heater is set on 120* F Friction Loss thru Fittings.

15 Slide 43 Solution for Problem Two Determine the required flow ¾ Pipe-Supply: 17 x 200= 3400 BTU ½ Pipe-Return: 13 x 200= 2600 BTU Total: 6000 BTU 6,000/10,000 =.6 GPM 10,000 BTU = 1 GPM (reminder R.O.T) One GPM will ensure that the velocity remains below 4 feet/second One GPM allows you to select the smallest pump available for the job Slide 44 Solution for Problem Two Determining the Head Loss: ¾ =200 ft = head loss.88 ft (.44 x 2) ½ =200 ft = head loss 4.9 ft (2.45 x 2)» Total:» 5.78 ft Add 20% for fittings in the system» 1.16 ft» TOTAL:» 6.94ft Slide 45 Step 4 Pick a Pump GPM is.6 or 1gpm- needed to overcome heat loss Head or friction is 7 ft PUMP????? UPS 15-55SFC What happens is we go from ½ return to ¾ return

16 Slide 46 Outline of Problem Three System Parameters: Supply line: ¾ type L copper 200 feet of pipe Return line: ¾ type L copper 200 feet of pipe The water heater is set on 120* F Friction Loss thru Fittings. Floor Plan: 55 6 x 25 Hot Water Main: 50 feet of ¾ Type L Copper Return Line: 50 feet of ½ Type L Copper Slide 47 Solution for Problem Three Determine the required flow ¾ Pipe-Supply: 17 x 200= 3400 BTU ¾ Pipe-Return: 17 x 200= 3400 BTU Total: 6800 BTU 6,800/10,000 =.68 GPM 10,000 BTU = 1 GPM One GPM will ensure that the velocity remains below 4 feet/second One GPM allows you to select the smallest pump available for the job As a rule of thumb, always size domestic HWR systems for a flow of 1 gpm. As noted, one gpm will ensure that velocity is below 4 feet/sec. Slide 48 Solution for Problem Three Determining the Head Loss: ¾ =200 ft = head loss.88 ft (.44 x 2) ¾ =200 ft = head loss.88 ft (.44 x 2)» Total:» 1.76 ft Add 20% for fittings in the system».352 ft» TOTAL:» 2.11ft

17 Slide 49 Pick a Pump GPM is.6 or 1gpm- needed to overcome heat loss Head or friction is 2.11 ft PUMP????? UP10-16BU/ATLC Slide 50 UP10-16 Residential Product Selection UP10-16 The UP10-16 is designed for domestic hot water recirculation systems. Units are available complete with timer, aquastat, line cord, check valve (on union mounted models), isolation valve (on union mounted models), or a combination of features. All wetted parts are non ferrous as noted below (see page 16 of the UP Series Circulation Pumps Product Guide for a complete listing of the materials of construction): Rotor/Impeller Unit Stainless steel, EPDM, PPO, PFTE, Graphite Pump Housing Brass MS 58 Slide 51 Trouble Shooting Tips Noise Pump to large velocity over 4 ft per second Air in system Pin holes in copper pipe No Hot Water Recirculation Air not purged Power to pump Pump installed incorrectly

18 Hot water supply to house Dip Tube: forces cold water to enter at the bottom of the water heater ISO or Ball Valve ISO or Ball Valve (optional) Check Valve Cold water supply Ball Valve Circulator Pump Hose Bib Slide 52 Properly purging air from an HWR System: Return line connected to water heater drain Slide 53 Resources Grundfos Technical Institute Your local Grundfos Distributor Grundfos Handbook. Slide 54 Grundfos Hydronic+HWR Handbook Piping Strategies Pump Selection Installation Tips Troubleshooting References Etc

19 Slide 55 Thank you for your attention