Monday, 22 July 2013

BQ - MEP System Swimming Pools





 
 http://www.haywardnet.com/inground/products/energysolutions/calculator/index.cfm?CFID=28795594&CFTOKEN=35914519
 
Step 1) Length, Width & Depth
Firstly measure your pool’s width, length and average depth. Write the measurements down in feet or meters, using decimals to approximate fractions of feet. (In other words, 20 feet, 3 inches would be 20.25 feet.)

Step 2) Calculate Pool Surface Area
Multiply the length of your pool by its width to determine its surface area.
Example: 10m x 5 = 50 m2   or   33ft x 16.5ft = 544.5 ft2
The surface area of a swimming pool can help determine the BTU size of pool heaters.
Pool Shape Formula

Rectangular
Surface Area = L X W

Round
Surface Area = 3.14 X (D/2) x (D/2)

Kidney
Surface Area = .45 X (A + B) L
Step 3) Pool Surface Area x Pool Depth
Multiply the pool’s surface area by its depth.
Example: 50 m2 x 1.2m (depth) = 60  or   544.5 ft2 x 4 (depth) = 2178

Determining the gallons of water in your swimming pool can help determine such thing as the size of your pump and filter. The gallons of water depends on the shape of your pool.
Gallons of Water calculator

aD = Average Depth

Pool Shape Formula

Rectangular
Gallons = Length x Width x Average Depth x 7.5

Round
Gallons = Diameter x Diameter x Average Depth x 5.9

Oval
Gallons = Long Diameter x Short Diameter x Average depth x 5.9

Step 4) Calculate Pool Volume
If you have measured your pool in feet multiply the figure calculated in Step 3 by 6.25 to determine how many gallons of water your pool holds. This formula will work only if your pool is perfectly rectangular.  If you have measured your pool in meters, multiply the figure calculated in Step 3 by 1.0 to determine how many cubic meters of water your pool holds.
Example: 60 x 1.0 = 60 Cubic Meters  or  2178 x 6.25 = 13612.50 UK Gallons
Circular Pools
Diameter (ft.) X Diameter (ft.) X Average Depth (ft.) X 5.9 = Total Pool Capacity in Gallons
Oval Pools
Length (ft.) X Width (ft.) X Average Depth (ft.) X 6.7 = Total Pool Capacity in Gallons
Rectangular Pools
Length (ft.) X Width (ft.) X Average Depth (ft.) X 7.5 = Total Pool Capacity in Gallons

Step 5) Convert UK Gallons to Cubic Meters
If you already have your pool volume in cubic meter then disregard this step.
As most swimming pool pump charts display cubic meters and not UK gallons you must do this conversion now. To convert UK gallons to cubic meters, divide the number of gallons you calculated in Step 4 by 220.
Example: 13612.50 Gallons divided by 220 = 61.88 Cubic Meters of Water

Choose a Swimming Pool Pump
Step 6) Approximate Pool Turnover Rate
A pool turnover rate is the amount of hours it takes to circulate the whole of your pool water through your swimming pool filter. Please select from the options below, the operation that relates to your swimming pool.
Outdoor Domestic Pool – Heavy Use – 4 Hours
Outdoor Domestic Pool – Light Use – 6 Hours
Indoor Domestic Pool – 8 Hours
Commercial Pool – 2.5 Hours
Hydrotherapy Pool – 1 Hours

Step 7) Minimum Flow Rate
Divide the number of cubic meters of water your pool holds (Step 4/5) by the number of hours you selected in Step 6.
For example if you have an indoor pool measuring 10m x 5m x 1.5m you would have calculated your pool to have 75 cubic meters of water (10 x 5 x 1.2 x 1.0m3).
60 cubic meters divided by 8 hours = 7.5 Cubic Meters / Per Hour
This figure will determine the minimum flow rate you need use to ensure the water in your pool can make a complete circulation.
Flow rate is simply the number of gallons the pump moves per minute. Turnover is the minimum amount of time it takes to circulate all the water one time through your pool's filter. In general, an average turnover of every 6 to 8 hours is sufficient for most pools.
Use this formula to determine your turnover rate:

Pool Volume in Gallons ÷ Turnover Rate in Minutes = Flow Rate

Example:
If you have a 25,000 gallon pool, and you want the water to turnover once every 8 hours:
25,000 ÷ 480 (60 minutes X 8 hours) = 52 gpm
Your 25,000 gallon pool needs an output of 52 gallons per minute to circulate the water once every 8 hours.

Step 8 ) Pipework Maximum Flow Rate
Determine the maximum flow rate your pool can handle by looking at its plumbing system. Most domestic pools use 1.5 inch pipes, which can handle about 9 cubic meters per hour on the suction side and 15 cubic meters per hour on the return side.
A 2 inch pipe can handle more than this with about 15 cubic meters per hour on the suction side and 25 cubic meters per hour on the return side, while a 3-inch pipe can handle more than 34 cubic meters per hour.
Use a slightly lower flow rate if your plumbing has a lot of intricate turns and connections that could be stressed by too much rushing water.

Step 9) What is your Pool Filters Maximum Flow Rate?

 Solving for pump flow rate.
pump flow rate 
 
You need to check at this point to make sure your filter’s maximum flow rate, specified by the manufacturer, will accommodate the size of your pump you are going to choose.
If you do not have a swimming pool filter you need to choose one of a larger size if you want the cleanest water with the lowest amount of maintenance. You will need to clean the filter when it becomes clogged with debris. A larger filter will take longer to clog.
Example: Your pool has a minimum flow rate of 7.5m3 per hour and you use 1.5 inch pipes which will give you a maximum head of 15 cubic meters per hour but you have a 20 inch filter that has a maximum flow rate of 10 cubic meters an hour then 10m3 is the highest flow rate you should be using. If you have a 30 inch filter that has a maximum flow rate of 21 cubic meters an hour than you are able to push this amount of water through. However as you only have 1.5 inch pipework there is no point going over 15 cubic meters an hour as there is only so much water you can get through the pipe at any one time.
The size of your pool's pipes determines the maximum flow rate in your pool. Count your pool's number of intake lines and refer to the common pipe sizes below:
  • For each 1.5" intake line, the maximum flow rate is 42 gpm.
  • For each 2.0" intake line, the maximum flow rate is 73 gpm.
Example:
Two 1.5" intake lines = 84. The maximum flow rate is 84 gpm.
This number is important because your pool filter has a maximum flow rate, which is measured in gpm. The pool pump's gpm rating should be below the pool filter's maximum flow gpm rating. If the pool's turnover rate is higher than the filter's maximum gpm, the filter is undersized and will not work properly or become damaged. If the filter is undersized, it should be replaced, or the pump should be undersized to prevent damage to the filter.

Step 10) Flow Head

The total resistance to flow is measured in “meters of head”.  As you will notice from looking at the individual pump charts, the greater the resistance to flow (expressed in meters of head), the lower the flow rate.  The greater the resistance to flow, the more powerful the pump needs to be to overcome it.
As a general rule, most domestic pools have a head resistance of 10m. Some installations do have a larger head and some may be smaller but we take an assumption that 10m is the average.
Therefore when looking at the flow charts use 10m as the head.

Step 11) Selecting the Most Appropriate Pool Pump

Each pool pump will have a flow chart detailing which pumps have what flow rate at what head. Select a pool pump with a flow rate between your minimum and maximum allowance taking into consideration your filters maximum flow rate.
Example: Your pool has a minimum flow rate of 7.5m3 per hour and you use 1.5 inch pipes which will give you a maximum head of 15 cubic meters per hour and your filter will allow you to go up to 21 cubic meters an hour. Therefore an ideal  level for you would be between 7.5 cubic meter and 15 cubic meter per hour.
If you have a pool with no spa or other complications you can choose a pump in the lower of the ideal range i.e. 7.5 to 9 cubic meters per hour. If you have a pool/spa combination, you need to consider the flow requirements of the spa jets.  This will often push you towards a pump on the higher end of the acceptable scale.  In that case, we would look for a pump in the 12 to 15 cubic meter range.
If you have a pool/spa combination, you might want to consider a 2 speed pump.  It can run on low speed while it filters the pool, and then switch to high speed when using the spa.
Example: As you can see from the following pump graph for the Espa Silen Swimming Pool Pump range we have noted down the minimum flow of 7.5m3 per hour and the maximum flow 15m3 per hour and also the head of 10m which we get from step 10. We have drawn a line horizontally for the head and vertically for the flow rate. As you will see the vertical lines of the min and max flow rate meet the horizontal line of the head. Where they meet you will see red curves relating to 5 pump sizes. It is here where we can correctly size the pump for your pool. In the case of a pool with no spa or other complications we indicated that you can choose a pump in the lower of the ideal range i.e. 7.5 to 9 cubic meters per hour. Therefore as the vertical line of 7.5m3 touches with the red curve of the 30 (0.33hp) model we can use this. However as it will be the minimum, you may want to consider the 50 (0.5hp) model as you can see from the green vertical line this version will pump 10.5 cubic meters an hour.

 

All pumps are of different qualities and power so be sure to check the ratings before you decide on a pump. Please call us on 01895-672515 to discuss this in further detail.
The Size of Inground Filters
The most important factor of the size of the Swimming Pool Filter is the GPM your Pool Pump produces. Filters have a designed flow rate. This designed flow rate should be higher than the size of your GPM your pool pump produces.

In the example above we were using the Hayward Super pump that produces a 58 GPM at 30 feet of Head. If we were to choose the Hayward Star Clear Plus as our chosen filter we would use the chart found on the description page


Performance Data--Residential
Turnover (In Gallons)
Model Number Effective Filtration Area Design Flow Rate* 8 Hours 10 Hours
C7512 75 ft2 75 GPM 36,000 45,000
C9002 90 ft2 90 GPM 43,200 54,000
C12002 120 ft2 120 GPM 57,600 72,000
C17502 175 ft2 120 GPM 57,600 72,000
The size of the filter that could handle the 58 GPM Super Pump would be the C7512.

swimming pool filters

Step 12)Calculating Resistance
Every piece of swimming pool equipment connected to your pool's circulation and filtration creates resistance to water flow. This includes the length and size of the pipe, the type of filter and features like heaters and pool cleaners. The total amount of resistance is called "feet of head"; the greater the feat of head, the stronger your pump needs to be to overcome it.  Even if you have an older pool and don't know some of these factors, it's possible to determine the pool's feet of head. Use a pressure meter and this formula:
  • Check the pressure of water flowing into the filter tank and multiply that number by 2.31.
  • Get a vacuum reading on the pump suction line and multiply that by 1.13.
  • Add the two numbers together and the result is the total dynamic head.

Example:
If the water flowing into the filter tank is at 10 PSI, and the vacuum reading on the pump suction line is at 5 PSI:

Water flow into filter tank: 10 PSI x 2.31 =
23.10

Vacuum reading on pump suction line: 5 PSI x 1.13 =
+ 5.65

Total resistance =
28.75 ft. of head
 
Pool Accessories
Pool CleanerVacuums dirt and debris from pools. Models range from manual to robotic cleaners that clean the pool automatically in as little as three hours. 
SkimmerThese easy-to-use hand-held nets make cleaning the surface of your pool a breeze.
ThermometerLets you check the pool's temperature before you take a dip.
Pool Test Kit: Check the chemicals, alkalinity and pH balance in your pool with a pool test kit to maintain safety and water clarity.
Safety AlarmSounds a loud alert when someone falls into the pool.  Essential for families with small children and pets.







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