PipeSystem Design

Thereport below details the calculations and diagrams used in thecalculation of pressure for a piping system. In the case of acondenser, it will be integrated into an open system. Thecalculations for the GPM were derived from the summation of the totalunit cols that will be in all floors 15 (floors) * 450,000BTU/hr andthat of the make-up air coil load (250,000BTU/hr) to give900,000BTU/hr. The total load was multiplied by 1.25 and divided bythe product of the temperature difference and 500. (500 * 10) to give2250GPM.

Silent Check Valve

Piping Drain Valve

Strainer

For an opensystem E

12’ D

TowerScreen

A

30

BalancingValve

B

C: Condenser 2250 GPM

25’

Fora 2250 GPM condenser, we should select a 12’’ pipe at 7 ft./100feet resistance then proceed with calculations.

Ato B: 30 ft 12’’ at 7 ft / 100 feet of resistance = 2.1

Ato E: 12 ft 12’’ at 7 ft / 100 feet of resistance = 0.84

Bto C: 25 ft 12’’ at 7 ft / 100 feet of resistance = 1.95

Cto D: 42 ft 12’’ at 7 ft / 100 feet of resistance = __2.94__

7.83

50%of fittings __3.915__

Pipingand Fittings resistance __11.745__

Pipingand Fittings resistance 11. 745

Strainer 7.7

Condenser 9

Staticlift 12

Nozzles5psig * 2.31 __11.55__

TotalSystem Resistance __55.995__

Explanationof the calculations made above

PressureHead. This is wherebythe fluid is pumped from a vessel at a different pressure from theone where it is being directed to (Bergendahl, 2008).Boiler feed pumps as well as condensate pumps run through theapplication of this principle. In this case, water is delivered froman atmospheric receiver at 5 PSIG, to the deaerator. As a result thepump head of (5 psig) must be added to the other heads that have beenmeasured. This quantity has to be converted to feet. This is done bymultiplying it by 2.31. Consequently, the figure added to the otherheads is approximately 11.55feet. This consideration is only done inopen systems as it is not a major factor in the closed system.

Frictionhead is also referred to as friction drop*.* Thismeasure is expressed in terms of “feet of head”. Asthe fluid flows between different components, it experiences somefriction with the surfaces. The result of this friction is that thetotal pressure in the system drops. This pressure, therefore has tobe incorporated into the calculations of the pump so that it may beable to overcome it. Some of the areas where there is a pressure dropas a result of friction head include chillers, boilers, piping,coils, heat exchangers, valves, and fittings (Morris, 1909). 

Velocityhead is calculated by squaring the fluid velocity and dividing it bythe gravitational constant multiplied by two. In this case, thegravitational constant used is 32 feet per second. 140 ft. 12’’

Moving up air coil

190ft. 12’

Boiler

Coil load

Fora closed system, static pressure will not be calculated. Therefore,the system will be divided into two circuits.

Circuitone:

190ft. 12’’ at 7 ft. / 100 ft. = 13.3

70ft. 12’’ at 7 ft. / 100 ft. = 4.9

190ft. 12’’ at 7 ft. / 100 ft. = 13.3

70ft. 12’’ at 7 ft. / 100 ft. = __4.9__

36.4

50%of fittings __18.2__

__54.6__

Circuit2:

190ft. 12’’ at 7 ft. / 100 ft. = 13.3

70ft. 12’’ at 7 ft. / 100 ft. = 4.9

190ft. 12’’ at 7 ft. / 100 ft. = 13.3

70ft. 12’’ at 7 ft. / 100 ft. = __4.9__

36.4

50%of fittings __18.2__

54.6

Conclusion

Theclosed system also has to incorporate the resistance at the globevalve as well as the two coils. In the latter diagram, the coilrepresents each of the coils that will be present in every floor ofthe building. As a result of this, the cumulative load is what willbe used to calculate the GPM of the coil. The moving up air coil isplaced only once in the building but has been represented in thefloor plan since it is a representation of what will be used tooperate the entire building.

Inthis case, the static head has not been considered, due to theabsence of any net change in acceleration. The value of each coil wasincorporated in the calculation of GPM and so the figure was includedin the above calculation (Morris, 1909). The Chiller’s GPM of 1500was divided by the number of coils that are available in the buildingso as to obtain the value of the load of one coil. If a chiller wasused instead of a condenser, then it would be in a closed system andits calculations would be similar to those used in a typical floorplan. In this case, however, the two systems operate differently andintegrating them together would require that the some balancingvalves are used, as indicated in the first diagram.

References

Bergendahl,J. (2008). *Treatmentsystem hydraulics*.Reston, VA: ASCE Press.

Morris,W. (1909). *Steampower plant piping system their design, installation andmaintenance,*.New York: McGraw-Hill.

Sixsmith,T., & Hanselka, R. (1997). *Handbookof thermoplastic piping system design*.New York: M. Dekker.