Integrated urban fountain design study

Integrated urban fountain design study

From requirement definition to preliminary calculations, implementation and delivery

In this chapter, the topics of the book are put together in the form of a hypothetical project. The aim is to show the relationship between architectural, hydraulic, mechanical, electrical and operational decisions.

An example project is a water feature of a pond in a city square, which creates several display modes by changing the group of fountains and lighting. The decision-making process starts from the user definition and continues until consumption estimation and adoption plan.

This sample is an educational study and preliminary design. Dimensions, nozzle specifications, assumed efficiencies and powers, actual product data or drawings are not applicable. The final selection of equipment and construction details requires site information, builders' documents and detailed design.

42–1. Project ID and employer's requirement

It is assumed that the employer wants a water feature to create a point of pause and public viewing.

The assumed depth is not a measure of pond safety. How to prevent unwanted entry, edge details, movement path and foreseeable hazards should be considered in the design.

In this example, the audio system is not in the base domain. Adding a musical show will require sound design, programming and checking the surrounding conditions.

42–2. Spatial organization and conceptual positioning

The nozzles are placed in four symmetrical groups. Each group can be changed independently of the others, but the six nozzles within it share a basic steering layout.

Placement must answer these questions:

• Visibility of the composition from the main viewing points.

• Collection of splashes in the area of the pond.

• Appropriate distance from the edges based on the splash test.

• Access to nozzles and lights for service.

• Coordinating with the pavements and the return path.

• Possibility of pipe and cable passage without interference.

To maintain design flexibility, the exact location of the nozzles is fixed after checking the spray pattern and wind conditions.

The repair access path should also be clear from the beginning. Opening a nozzle or lamp should not depend on extensive destruction of the coating.

Place Figure 42–1 — Sample conceptual plan

Suggested shape: 10 x 6 m pond with four groups of six, viewing points, access path and approximate location of the tank and facilities.

Subtitle: "Educational plan; Distances and installation details will be completed after selecting the equipment and inspecting the site.

42–3. Determining the hypothetical operating point of the nozzle

For educational calculation, it is assumed that the investigated nozzle has the following performance under certain conditions:

• Flow rate of each nozzle: 0.75 cubic meters per hour.

• Necessary pressure head at the nozzle inlet: seven meters of water column.

• Target output height: about three meters.

These three values are assumptions and are not extracted from the catalog of a specific product.

In the actual design, the curve or the manufacturer's table must be selected for the desired output shape. The height of the fountain is not the same as the required head at the nozzle entrance; Part of the energy is consumed in the nozzle itself and the formation of the output pattern.

The dependence of the nozzle on the water level should also be clear. For example, OASE introduces some nozzles dependent on the water level and some independent of it. This difference affects the placement and level control. OASE water level dependent nozzle sample ^[283]

Classic and control nozzles have also been introduced in GSO product groups. Actual model selection should be completed by receiving performance and installation information. GSO urban fountain nozzles and equipment ^[284]

42–4. Flow calculation and circuit architecture

The flow rate of each group of six:

$Q_{group}=6\times 0.75=4.5m^3/h$

The total discharge of the four groups in the main state:

$Q_{display}=4\times 4.5=18m^3/h$

In this example, an independent pumping set is considered for each group. Therefore, four pumps feed the circuit of six nozzles each.

This choice allows changing groups, but also increases the number of equipment and maintenance requirements. In the actual project, it should be compared with the option of common pump and control valves.

The conceptual path of the show circuit:

Tank → group pump → feeding path → collector and nozzles → basin → return path → tank

In this example, the purification circuit takes water from the tank and returns the purified water to the pond. As a result, the return path must collect the simultaneous flow of both systems.

42–5. Calculation of the loss of the feeding path of a group

For the common part of the path of a group, it is assumed:

The inner diameter of 40 mm is a calculation value and should not be attributed to a nominal size without checking the characteristics of the pipe.

Conversion rate:

$Q=\frac{4.5}{3600}=0.00125m^3/s$

Average speed:

$v=\frac{Q}{\pi D^2/4}=\frac{0.00125}{\pi (0.04{)}^2/4}\approx 0.995m/s$

Longitudinal drop with the Darcy-Weissbach relationship:

$h_f=f\frac{L}{D}\frac{v^2}{2g}$

$h_f\approx 0.025\times \frac{25}{0.04}\times \frac{0.995^2}{2\times 9.81}\approx 0.79m$

Local drop:

$h_m=\Sigma K\frac{v^2}{2g}$

$h_m\approx 8\times \frac{0.995^2}{2\times 9.81}\approx 0.40m$

The drop of this section is about 1.19 meters.

The coefficient of friction and local coefficients in the final design must be determined by the material, actual diameter, flow conditions and connections selected. The loss of distribution branches is also calculated separately.

42–6. Preliminary pump head and power of each group

For the critical path of a group, the following additional assumptions are considered:

Preliminary working point of each pump:

$Q=4.5m^3/hH\approx 10.8m$

Four independent pumps, each must provide the working point of its circuit; Their heads do not meet each other in this arrangement.

Assuming the total efficiency of electricity to water is equal to 45%:

$P_{in}=\frac{\rho gQH}{\eta }$

$P_{in}\approx \frac{1000\times 9.81\times 0.00125\times 10.8}{0.45}\approx 294W$

Estimated input power of four sets:

$P_{display}\approx 4\times 0.294=1.18kW$

This calculation is not the choice of motor rated power. The final selection depends on the pump curve, operating range, suction conditions, actual efficiency, level shift and performance in different modes.

The method of collecting static head and path drops in KSB pump selection sources is also described. Selection Guide for KSB Centrifugal Pumps ^[285]

Instead of Figure 42-2 — Critical path for head calculation

Suggested figure: Schematic section from the water level of the tank to the nozzle, showing the level difference, pipe length, smoothness, connections and critical branch.

Subtitle: "Each head component must be associated with a specific part of the actual path."

42–7. Water volume, tank and return after stopping

Preliminary volume of pond water:

$V_{basin}=10\times 6\times 0.30=18m^3$

It is assumed:

• Water volume of the reservoir in the base condition: three cubic meters.

• Approximate volume of water inside the lines and components of the circuit: 0.20 cubic meters.

Therefore, the operating volume is the basis of calculation:

$V_{system}=18+3+0.20=21.2m^3$

To control part of the estimation of lines:

$V_{fourpipes}=4\times 25\times \frac{\pi (0.04{)}^2}{4}\approx 0.126m^3$

A difference of up to 0.20 cubic meters is assumed at this stage for other lines and components and should be corrected after the completion of the map.

Return water acceptance

It is assumed that the maximum water that can be returned from the lines is 0.20 cubic meters and the estimated share of suspended water is 0.01 cubic meters:

$V_{return}=0.21m^3$

If a hypothetical rainfall event of 20 mm falls directly on the 60 square meter surface of the pond:

$V_{rain}=60\times 0.020=1.2m^3$

The sum of these two inputs:

$V_{additional}=0.21+1.2=1.41m^3$

For the preliminary study, two cubic meters of actual free capacity of acceptance in the tank is assumed. This volume comparison is not a substitute for the design of area precipitation, instantaneous return capacity, overflow and consideration of other inputs.

The structural volume of the tank should also be determined in terms of free space, unusable volume, control levels and access.

42–8. Purification circuit and common return capacity

To teach the calculation method, the nominal circulation time is assumed to be three hours:

$Q_{treatment}=\frac{21.2}{3}\approx 7.07m^3/h$

Therefore, the initial basis of the treatment circuit is about 7.1 cubic meters per hour.

Three hours is not a general fountain requirement or a sufficient measure of water hygiene. The actual time and capacity should be determined by the type of use, water quality, equipment and water management plan. This volume ratio also does not mean that all the water passes through the purification at the same time; Mixing quality and flow path are important.

In the selected arrangement, the maximum continuous return current when operating simultaneously:

$Q_{return,steady}=18+7.1=25.1m^3/h$

Gravity path design should consider this flow along with precipitation and transient conditions. The diameter of the return path cannot be deduced from the diameter of the pipe under pressure.

Filter selection, disinfection, sampling location and injection logic require additional design. CDC guidelines for decorative fountains emphasize water management, cleaning, and disinfection programs. Guide to CDC decorative fountains ^[286]

42–9. Lighting and initial power budget

A hypothetical 12 watt lamp with 24 VDC power supply is assumed for each nozzle.

Output power of total lights:

$P_{LED}=24\times 12=288W$

Total current on the 24 V side:

$I_{DC}=\frac{288}{24}=12A$

This value is the sum of the loads and does not mean feeding all the lights with the same cable route.

For each group of six:

$P_{group}=72W{I}_{group}=3A$

Assuming 90% efficiency for power sources:

$P_{lighting,input}=\frac{288}{0.90}=320W$

24V voltage alone does not prove safety compliance. Source type, circuit conditions, zoning, cable, connection and protection should be determined according to electrical design.

Preliminary power budget:

The power of purification and control in this table is only the assumption of budgeting. Branching, protection and cable capacity should be determined after actual equipment selection and electrical specification review.

42–10. Control logic and work modes

Four main modes are defined for the instance:

The inputs considered include water level, wind, pump status, treatment conditions, and operator commands.

Low level protection should be connected to the dependent circuits and after the condition is cleared, the recovery should be done according to the approved logic.

For wind, the reduced or stopped state is determined based on the splash test. OASE also introduces wind-dependent control to limit adverse spray effects. OASE wind dependent control ^[287]

In this example, independent control of each nozzle is not foreseen. If such capability is desired, the architecture of valves, pumps, and control outlets must be revised.

42–11. Daily energy calculation

For the energy budget, it is assumed that the average power of the total display circuits in idle mode is 0.75 kW. This value is an independent training estimate and should be verified with the actual program.

In this table, the display power does not include brightness and filtering, and the two display modes are not executed at the same time.

Ten hours of purification work is also a calculation assumption; The final plan must meet the water management requirements.

Annual consumption is calculated by adding up the days with different plans and conditions. Directly multiplying this sample day by the number of days in the year, without checking for stops and seasons, does not produce a reliable estimate.

42–12. Compensatory water estimate for the sample day

For a dry day, it is assumed:

As a result:

$M=0.30+0.08+0.20=0.58m^3/day$

The estimated compensation water of the sample day is 580 liters.

This value is different from the flow rate of 18 cubic meters per hour. Circulating water is often used, but system outputs require compensation.

Evaporation and spray volumes are assumed in this example and should be modified by site conditions and field testing. The initial dewatering of 21.2 cubic meters is also a separate event.

Figure 3-42 — Sample day's balance

Suggested figure: showing 580 liters of compensating water against the water outlet components, clearly labeled "Teaching Values".

Subtitle: "Circulation flow rate, storage volume and compensation water are three different quantities."

42–13. Structure, sealing and maintenance access

The initial dimensions of the pond are not enough to determine the wall and floor thickness. Structure design requires information on soil, loads, joints, groundwater conditions, and other requirements.

The items required to complete the plan are:

• Checking the structure in full and empty state.

• Pipe and cable joint details.

• Choosing a suitable sealing system.

• Slope and drain for maintenance.

• Installation details of lights and nozzles.

• Resistance and locking of valves.

• Access to the pump, filter and valves.

• Exit route of equipment for repair.

• Conditions of ventilation and flooding of the facility space.

The location of all buried parts must be coordinated with the mechanical and electrical drawings before implementation.

For sensitive details, limited sampling or testing can reduce ambiguity. Crystal Fountains also offers prototyping, installation review and commissioning support in its technical services. Crystal Fountains technical and prototyping services ^[288]

42–14. Executive package and initial list of equipment

At this stage, the following checklist is prepared for design development:

The implementation plan should cover design, documentation review, procurement, construction operations, installation, testing and training.

Important stopping points include checking buried components, sealing acceptance, testing covered circuits and verifying readiness before energization.

42–15. Sample test and acceptance program

For this project, tests should check the performance of each group and set.

Acceptance limits should be determined before the test. For example, a target height of three meters is not a complete acceptance criterion without specifying tolerances, wind conditions, water level and measurement method.

After correcting each defect, the related tests are repeated. The final status of the settings will also be recorded in the delivery file.

Figure 42–4 — Sample project integrated test

Suggested image: suitable archival photo of the water fountain test, along with the placement of the measurement tool. If the photo belongs to another project, its real name and description should be included.

Suggested subtitle: "Sample of performance test documentation; The image is not a representation of the hypothetical project of this season.

42–16. Necessary documents to convert the study into a workable plan

The main results of the preliminary study are:

• Four groups of six.

• Target discharge of each group: 4.5 cubic meters per hour.

• Preliminary computing head of each group: about 10.8 meters.

• Full display flow rate: 18 cubic meters per hour.

• Hypothetical operating volume: 21.2 cubic meters.

• Educational basis of treatment flow rate: about 7.1 cubic meters per hour.

• Joint return continuous flow: about 25.1 cubic meters per hour.

• Sample day energy: about 14.4 kilowatt-hours.

• Compensatory water sample day: about 580 liters.

To turn this study into an implementation plan, the following must be completed:

1. Collection and climatic and infrastructural information of the place. 2. Actual nozzle selection and performance verification. 3. Calculation of the distribution and return network. 4. Selecting the pump and checking suction and all working modes. 5. Reservoir design, overflow and control levels. 6. Treatment design and water management plan. 7. Electricity and protection calculations and maps. 8. Structure design, sealing and architectural details. 9. Control logic, input and output list and display program. 10. Test criteria, delivery documents and maintenance schedule.

Any changes in the main assumptions must be carried over to the dependent calculations. Changing the nozzle model can change the flow rate, head, power, return capacity and control program; Therefore, the final version of the documents must be reviewed and registered in a coordinated manner.