water source application & competitor comparison

Water Source Water Source Application & Application &

Competitor ComparisonCompetitor Comparison

Water Source Water Source Application & Application &


Water Source Product SelectionWater Source Product Selection

Piping SizingPiping Sizing

Water CoolerWater Cooler


Content

Selection Criteria?

1. Capacity required, Total Cooling (TC), Sensible Cooling (SC)2. Entering Air Temperature, DB/ WB

3. Entering/ Leaving Water Temperature, EWT/ LWT

4. Airflow required, CFM

5. Static pressure, Ps

5. Water Flowrate, l/s

Water Source Product Selection

Entering Air Temperature, i. Entering Dry Bulb, EDBii. Entering Wet Bulb, EWB

Tip: DB changes while WB remains will not affect the TC.

SC2(kW)=SC1(kW)+ [1.23*(l/s)*(1-BPF)*(EDB2-EDB1)/1000]

Example: if TC =3.52kW and SC=2.78kW at EDB =27C, EWB=19C. Calculate the TC and SC when EAT is as following;

EDB = 30C, EWB = 19C

Assuming air flow rate = 180 l/s, BPF=0.06, Water flowrate = 1.25m3/hr

Manual Selection & Calculation

Since WB1 = WB2, then TC1 = TC2 = 3.52kW, and

TC = 3.52kW and SC=2.78kW EDB =27C, EWB = 19C

EDB = 30C, EWB = 19C

SC2=SC1+ [1.23*(l/s)*(1-BPF)*(EDB2-EDB1)/1000]

= 2.78+[1.23*180*(1-0.06)*(30-27)/1000] = 3.40kW

Manual Selection & Calculation

Selection & Calculation by Selection SoftwareDownload selection software from e-biz.

1. Select model type

2. Select indoor if split type was chosen

3. Chose the fan speed

4. Key in the water flow

5. Key in the on coil temperature and EWT temperature

6. Key in the designed capacity to fulfill the building heating/cooling load requirement.

7. Key in the capacity tolerance (%)

8. Click “Calculate”

Selection & Calculation by Selection SoftwareSelection Result

9. Select the model closest to the capacity requirement

Example of Piping Sizing

1. Determine System Water Flow Rate- DON’T sum up directly the total nominal water flow of each WSHP unit.

- Total System design flow rate is determined by the performance of the water cooler, where most of them are evaporative type and is very much dependent on the entering air wet bulb temperature.- Lower flow rate are preferred in areas with

lower wet bulb temperatures. In more humid areas, a higher water flow rate will supply a higher water temperature to water source units, but with a lower differential.


2. Determine WSHP unit flow rate- Total Cooling load must be known.

- Diversity Effect must be considered. This is to prevent over sizing water cooler

Diversity Factor = Block Load / Σ(Peak Load)

- Recommended diversity factor;

- 85% for system up to 40 tons

- 80% for system between 40 and 60 tons

- 75% for system greater than 60 tons

- System diversity will only affect the range of the water cooler.


2. Determine WSHP unit flow rate (Cont…)

Range of Water Cooler, Rs = Twi – Two

Where;

Twi = entering water temperature

Two = leaving water temperature- By using diversity factor, D, we can then calculate the avarage

range of the water source units, Rp

Rs = D * Rp

- Where typical value of range are between 5C to 8C or equally 9F to 14.4F.


3. Determine individual unit peak cooling load- By assuming 30% of heat rejection ratio,

Qh = 1.3 *D* Qc

Total heat rejection, Qh

Total cooling peak load, Qc

Qh = mw * Cp * (Twi – T wo)

Where

mw = mass flow rate of water

Cp = water specific heat

- By replacing with known constants, we will get these familiar equations;

Qh = 500 gpm (Twi – T wo)


3. Determine individual unit peak cooling load (Cont…)

- By having water cooler range, Rs in the equation;

Qh = 500 * gpm * Rs

- By having total peak cooling load, Qc in the equation;

1.3 *D* Qc = 500 * gpm * Rs

- Thus the individual unit peak cooling load, qc

1.3 * qc = 500 * gpm * Rp


Example:

A water loop system consists of 30 units of water source heat pump units with a combined total peak loading of 450,000btu/hr. the system is served by a centrifugal water pump. A closed loop water cooler is used to give a leaving water temperature of 30C. the ambient air wet bulb temperature is 25C.

-Determine the required total system water flow rate.

From the given table, at 25C wet bulb temperature, the water flow rate is 2.36 gpm/ton.

Therefore, the total system water flow rate is 2.36 gpm/ton * (450000/12000)ton = 88.5 gpm.

-Calculate the average range of the water source units

The system range is first calculated;

Rs = 1.3 * D * Qc / gpm / 500 = 1.3 * 0.85 * 450,000 / 88.5 / 500 = 11.24F or 6.24F

Rp = Rs / D = 13.22F or 7.35F

-If one of the water source units has been designed to give a cooling capacity of 11,000btu/hr, calculate the water flow rate required.

Rp = 1.3 * qc / gpm / 500 13.22 = 1.3 * 11000 /gpm/500 ; gpm = 2.16gpm

-Recalculate if there is no diversity factor is applied.

If D = 1, and maintaining the flow rate, Rp = Rs / D = 13.22F or 7.35F


4. Piping Sizing

- Important to ensure the selected water pump is sufficient to deliver the required water flow rate.

- To do this calculation, it is important that a detailed drawing layout of all components in the system is available.

- The layout should give dimensional lengths of the piping network.

- Location of water cooler, pumps and boiler must be identified.

- All fittings and accessories used in the piping installation should be clearly identified.

- Study the pipe circuit layout and do preliminary check if the circuits are balanced. Re-arrange if necessary. Use balancing valves only if it is not possible to have balanced circuits.

- Size the pipes by using the pipe chart. The water velocity should be in the range of 2 – 9 fps, with a recommended max friction loss of 10 ft of water per 100 ft.


4. Piping Sizing (Cont…)

- Calculate equivalent pipe length. Include the losses for all the valves and fittings used. Calculate the total pipe friction loss by using the friction loss value from the pipe chart. Add this with the pressure drop in heat exchangers, water cooler and boiler.

- Select a pump which will match these total system water flow rate and total head pressure.


Example:

The water source units which serve the main building has a total installed cooling capacity of 560,000 btu/hr (peak load).

There a altogether 40 sets, with 10 sets for each of the four floors (1st floor to 4th floor).

The water source units have been selected based upon the following conditions:

Entering air = 25C DB / 18C WB

Entering water = 32C

All the units are connected to an evaporative water cooler located on top of an adjoining service building outside of the main building.

The outside air wet bulb temperature is at 24C


Example: (Cont..)

1. Calculate the total system water flow rate.

Total installed capacity = 560,000 btu/hr (46.67 tons)

Therefore, the total system water flow rate @ 24C wet bulb is

2.19 gpm/ton * 46.67 tons = 102.2 gpm.

2. Calculate the range (Rs) of water cooler

For 46.67 tons, use diversity factor of 0.80.

Rs = 1.3 * D * Qc / gpm / 500 = 1.3 * 0.80 * 560000 / 102.2 / 500 = 11.40F or 6.3C.

3. Calculate the range (Rp) of water source units.

Rp = Rs / 0.80 = 11.40/0.80 = 14.25F or 7.9C.


Example: (Cont..)

4. The unit on the 4th floor have been sized to give the following peak loads;

By using equation 1.3 * qc = 500 * gpm* Rp, we can then work out the flow rate through each of these units. Let assume that the total system water flow rate is distributed to all the four floors of the main building in this manner.


Example: (Cont..)

5. With this, we can no look into the pipe sizing all the way up to 4 th floor. Focus is given to determine the route of least favourable which will give the max friction loss to the water pump. i.e. all the way to unit q.

Reference is then made to pipe chart to determine a suitable pipe size.


Example: (Cont..)

6. Each of the WSHP has fittings as shown in the diagram below:

The water pump has been installed in this manner:


Example: (Cont..)

Detail of water pipe connection to the evaporative water cooler is as shown below:


Example: (Cont..)

7. With all these fittings details and pipe lengths, we can now calculate the pipe friction loss from the water cooler to point q. This is as demonstrated in this summary table.


Example: (Cont..)

Type of Water Cooler

1. Closed Circuit Cooling Tower

2. Open type cooling tower with heat exchanger

3. Dry Cooler

Evaporation of Water to cool the condenser

Air Cooled

Water Cooler

Terminology

An evaporative equipment that

exposes water exposes water

directly to the cooling directly to the cooling

atmosphereatmosphere, thereby transferring the heat load directly into the air.

Open Cooling Tower

Water Cooler

Terminology

An evaporative equipment that contains two separate fluid two separate fluid circuitscircuits. The first is an externalexternal circuit where water is exposed to the atmosphere as it cascades over the tubes of a coil bundle. The second is an internal internal circuit in which the fluid to be cooled circulates inside the tubes of the coil bundle.

Closed Circuit Cooling Tower

Water Cooler

Terminology

Type of mechanical draft tower in which one or more fans are located at the air inlet to force air into the tower.

Forced Draft Type of mechanical draft tower in which one or more fans are located at the air outlet to induce air through the air inlets

Induced Draft

Water Cooler

Terminology

In a counter flow cooling tower, the air enters at the base of the tower, flows upwards and interfaces counter currently with the falling hot water.

Counter Flow

In a cross flow cooling tower, the air flows horizontally through the cooling tower and interfaces perpendicularly with the falling hot water.

Cross Flow

Water Cooler

Terminology

The diff between the water temperature leaving the cooing tower and the wet bulb temperature of the cooling air (atmosphere)

Approach

Water Cooler

Terminology

Loss of water from the cooling tower as a result of evaporation of the circulating water;

Evaporation Loss

%E = [Range(C) * Circulating flow rate (kg/hr) * 100]/600Where range = the diff between the leaving and entering water temperatures of the cooling tower.

Water Cooler

Terminology

Loss of water from the cooling tower as a result of carry over of minute water droplets scattered about as drifted by the fan.

Drift Loss

The amount of water discharge from the cooling tower to prevent concentration build up of dissolved minerals which may cause the formation of algae or scale.

Blow Down Volume

Water Cooler

Terminology

The amount of water that is required to maintain the water level in the cooling tower basin.

Make Up Water (M%)

M = E + C + B

Water Cooler

“Hybrid” System Closed Circuit and Open Circuit Tower

Water Cooler

Water Distribution System

- Open Basins

- Large Orifice, 360 Nozzles

- Easily accessed for maintenance

- Basin water level used to balance flow

1. Gravity Distribution

- Pressurized systems

- Large Orifice, 180 directional Nozzles

- spray header and branches

2. Spray Distribution

Water Cooler

Air Moving

- >80% is used in HVAC system

- High volume, low static pressure

- High efficiency

- Low energy consumption

- Improve sound ratings

1. Axial Fan

- High volume, high static pressure

- High energy consumption

- Quiet operation

- Tight layout requirement

2. Centrifugal Fan

- Example, 1500 GPM, 95F EWT. 85F LWT, 78F EWB

- Counter flow centrifugal fan unit requires 60 HP- Cross flow axial fan unit requires 30 HP

* Axial fan requires less HP than centrifugal fan*

Water Cooler

Cooling Tower Equipment Layout

- Prevent warm air or drift from being introduced into fresh air intakes or from being carried over populated areas

- Consider the potential for plume

- Note the direction of the prevailing winds

- Ensure adequate supply of fresh air to the air intakes

- Provide adequate space for piping and proper servicing and maintenance

- Top of the unit discharge must be at least level with the adjacent wall

Water Cooler

Layout Example

- Adjacent to a wall or building

- In an enclosure

- Adjacent t a louvered or slotted wall

Water Cooler

Layout Example

- Correct cooling tower installation when located adjacent to a building or wall- Maximum air velocity should no t exceed 300 FPM or 1.5m/s

- Air entry envelope consists of top and two sides

- Based o 125,900 CFM, an inlet height of 10 feet and an air inlet length of 12 feet, the distance to the wall is ;

125,900/2 = (10+10+12)D*300

D = 6.56 feet

Water Cooler

Layout Example

- When cooling towers are positioned with air inlets facing each other, the distance between cooling towers is 2D

-If 125,900 CFM, an inlet height of 10 feet and an air inlet length of 12 feet, the distance to the wall is ;

125,900*2/2 = (10+10+12)D*300

D = 13.11 feet

Water Cooler

Layout Example

- Maximum air velocity should not exceed 400 FPM

- Center of the cooling tower within the enclosure for uniform air flow to the air inlets

-If 125,900 CFM, enclosure size is 30ft * 20ft ;

125,900 = 2*D*20*400

D = 7.87 feet

Water Cooler

Layout Example

- Louver must provide at least 50% free area

- Louver air velocity should not exceed 600 FPM

- Maintain at least 3 ft between the tower air inlets and the louvered wall.

Water Cooler

Maintenance – Who needs this?

Water Cooler

Maintenance

Maintenance and water treatment are the most neglected regimens of cooling tower operation, and cooing towers are generally the most neglected components in the mechanical system

WHY???

- Remotely located & difficult to access

- Limited maintenance resources

- People, Training & budgets.

Water Cooler

Maintenance

Review major cooling tower system sand their appropriate maintenance regimens:

- Circulating Water

- Fan & Drive

- Fin & Coil

- Air Entry Louvers

- Drift Eliminators

Water Cooler

Maintenance

Reputable manufacturers provide maintenance instructions and check sheets. It is best to follow the manufacturer’s recommendations!

ASHRAE Handbook also provides a good general guide.

Water Cooler

Circulating Water System Types

Cross flow tower operation

View of water distribution box

Gravity Flow Water Distribution System

Water Cooler


Closed Circuit Tower Operation

View of Pressurized Distribution System & Nozzles

Pressurized Flow Water Distribution System

Water Cooler


Spray nozzles & water distribution boxes need to be inspected & cleaned

- After start up and

- Monthly thereafter

Regular inspection allows quick treatment and control of

corrosion and mechanical failures.

Water Cooler


Clogged distribution nozzles cause:

- Reduced or mal-distributed water flow = capacity reduction

- HE surface scaling/ fouling = capacity reduction

- Overflowing distribution boxes = water & chemical loss

- Excessive drift = water & chemical loss

- Fan motor over-amping (forced draft) = reduced motor life

Water Cooler


Suction Strainers:

- Designed to protect pump & nozzles

- Inspect & clean weekly

- Operating environments laden with airborne fibrous material ( agricultural, paper, textile processing demand more frequent strainer cleaning)

Water Cooler


Poor Strainer maintenance leads to :

- Reduced flow = reduced capacity

- Pump cavitations = pump repair cost and objectionable plant noise

- Collapsed strainers = tower repair costs

Water Cooler


Basin Maintenance :

- Clean and flush monthly

- Inspect and repair corrosion

Accumulated solids ;

- Clog equalizer & bypass lines

- Hide corrosion cells

- Give breeding environment for bio growth

Water Cooler


Closed Circuit Tower Water Pumps;

- Inspect seals & free rotation of shaft monthly.

- Lubricate bearings per motor manufacturer instructions.

Water Cooler


Make-up Water and Operating Level Controls;

fff

Mechanical float valve

Electric valve & sensor

Water Cooler


Set operating level and water supply pressure to manufacturer’s recommendations

-Inspect water level an adjust float monthly

- Inspect valve seals and full shut off monthly

Clean electronic sensing elements as required.

Water Cooler


- Malfunctioning level control can be costly with water and chemical loss and even equipment damage.

- Proper water level control is

required for pump priming and

Prevention of air entrainment

in suction lines.

Water Cooler

Fan & Drive System

The fan system moves the air which cools the water. It is critical to keep the fan system in top operating condition!

- Daily walk around the tower and listen for unusual noises or vibration

- if reasons for vibration are easily detected, (loose belts, loose motor base, loose bearing locking collars, loose fan or sheave bushings) correct as required.

- if causes of vibration are not easily detected, consult a specialty vibration analysis contractor.

- Quarterly clean fan of heavy debris (trash, bird droppings, scale) and inspect the fan and drive components for tight fasteners, missing balance washers & structural integrity.

Water Cooler

Fan & Drive System

- Repair or replace corroded hardware, even the fan if necessary

- Check the mechanical equipment support for cracks and tight hardware

- Check security of fan guards

Water Cooler

Fan & Drive System

Belt Tensioning

- Check 24 hours after start up

- Check monthly thereafter

- 1/2 “ to ¾” deflection with moderate finger pressure at center span of belt. Check manufacturer’s OM guide.

Water Cooler

Fan & Drive System

Lubrication

- Check oil level weekly

- Change oil 500 hours or 4 weeks after start up.

- Follow gear box OM guide for oil type and change frequently.

- Recommend synthetic, oxidation inhibited oil

Water Cooler

Fan & Drive System

Drive Shafts

- Inspect drive shaft and coupling hardware monthly

- Inspect coupling flex elements for buckling and fatigue damage. Replace as required.

Water Cooler

Fan & Drive System

Fan Shaft Bearing

Lubrication Schedule

- 1000 hours or 3 months for induced draft

- 2000 hours or 6 months for forced draft

- Use water resistant grease approved by manufacturer

Water Cooler

Fan & Drive System

Motors

-Wire per nameplate and check rotation

- Multi- lead (9,12 wire) motors may be confusing

- Check multi speed motor rotation at both speeds

- Check current draw on start up

- Check operational controls

- Set proper time delay between speed changes

- Set thermostat differentials to limit fan cycling (3-6 starts/

hour)

Water Cooler

Heat Transfer Surface

Open Tower Packing (Fill):

-Scale, solids & bio-fouling restrict air & water passages.

- Capacity diminishes rapidly with increased fouling

- Extra weight can damage fill and structural supports.

Typical fill clogging from bio-films and suspended solids.

Water Cooler

Heat Transfer Surface

Closed Circuit Tower Coil:

-Scale on coil walls is a direct heat transfer barrier

- Capacity diminishes with increased fouling.

Water Cooler

Water Cooler Available in the Market

Standard Features:

-forced draft counter flow design cooling towers with single module capacities from 10 to 100 cooling tons,15-600 GPM-Seamless Engineered Plastic (HDPE) Shell Corrosion Proof Construction -Forward Curved Centrifugal Blower with totally enclosed Motor. -Factory Assembled for Simple Installation 15 Year Shell Warranty -PVC Water Distribution System with Non-clog Large Orifice Removable Nozzles -High Efficiency PVC Fill -Made in the USA

Water Cooler

Water Cooler Available in the Market

Standard Features:

-induced draft counter flow design cooling towers with single module capacities from 55 to 250 cooling tons - Seamless Engineered Plastic (HDPE) Shell - Corrosion Proof Construction - Direct Drive Fan System - Totally Enclosed VFD Rated Motors -Factory Assembled for Simple Installation - 15 Year Shell Warranty - Low Pressure Drop Self Propelled PVC Water Distribution System - High Efficiency PVC Fill - Made in the USA

Water Cooler

Water Cooler Available in the MarketStandard Features:

- induced draft counter flow design cooling towers with single module capacities from 250 to 500 cooling tons single module capacities from 55 to 250 cooling tons - Seamless Engineered Plastic (HDPE) Shell - Corrosion Proof Construction - Direct Drive Fan System - Totally Enclosed VFD Rated Motors - Completely Factory Assembled - 15 Year Shell Warranty - Low Pressure Drop Self Propelled PVC Water Distribution system -High Efficiency PVC Fill - Made in the USA

Water Cooler

Standard Features:

- induced draft counter flow design cooling towers with single unit capacities from 250 to 2,000 cooling tons

- Corrosion Proof Construction - Direct Drive Fan System - Totally Enclosed VFD Rated Motors - Factory Assembled for Simple Installation - 15 Year Shell Warranty - High Efficiency PVC Fill - Made in the USA - Seamless Double Wall Engineered Plastic (HDPE) Shell- PVC Water Distribution System with Non-clog Large Orifice -Removable Nozzles

Water Cooler

WH11B WH12B HWP33 WH15B HWP41

Capacity, btu/hr 11600 12000 11260 14400 13989

Noise Indoor, dBA 42 37 45 41 45

Cooling EER, Btu/hrW 14.67 15.42 12.49 11.43 12.22

Height, inch 9.84 12.8 12.99 13.27 12.99

Width, inch 40.94 40.75 31.1 42.28 31.1

Depth, inch 19.49 19.68 19.09 19.68 19.09

Volume, ft3 4.54 5.94 4.46 6.39 4.46

Air Flow, CFM 380 380 180 470 403

1.5hp1.2hp

Competitor Comparison

WH20B HWP49 WH25B WH30B HWP78

Capacity, btu/hr 19500 16719 26000 29920 26614

Noise Indoor, dBA 45 45 47 50 59

Cooling EER, Btu/hrW 12.45 12.22 13.68 12.08 11.6

Height, inch 13.9 12.99 13.39 14.57 15.16

Width, inch 46.57 41.34 52.28 51.06 44.68

Depth, inch 21.26 20.08 21.26 29.33 22.24

Volume, ft3 7.96 6.24 8.61 12.63 8.72

Air Flow, CFM 600 540.31 870 940 1017

2hp 3hp


WH40B WH50B HWP140 HWP175

Capacity, btu/hr 44870 49880 48109 59710

Noise Indoor, dBA 50 51 63 64

Cooling EER, Btu/hrW 11.57 11.12 13 12.22

Height, inch 17.09 17.09 19.29 19.29

Width, inch 54.17 54.17 58.07 58.07

Depth, inch 31.18 31.18 24.02 24.02

Volume, ft3 16.70 16.70 15.57 15.57

Air Flow, CFM 1325 1470 1589 2204

5hp


McQuay Temperzone TemperzoneWH70B HWP210 HWP235

Capacity, btu/hr 76460 70287 78817

Noise Indoor, dBA 53 67 67

Cooling EER, Btu/hrW 12.66 13.31 13.31

Height, inch 19.68 21.06 21.06

Width, inch 62.05 62.8 62.8

Depth, inch 33.19 24.02 24.02

Volume, ft3 23.45 18.38 18.38

Air Flow, CFM 1940 2288 2606

8hp


Indoor Unit CC020C MCD518DB CC025C MCD524DB

Outdoor Unit WSS020A WTK518 WSS025A WTK524

Capacity, btu/hr 19000 18000 22000 24000

Noise Indoor, dBA 38 N/A 40 N/A

Cooling EER, Btu/hrW 11.8 N/A 13.9 N/A

Height, inch 10.28 10.16 10.28 10.16

Width, inch 41.93 37.24 47.24 37.24

Depth, inch 16.18 19.45 16.18 20.91

Volume, ft3 4.04 4.26 4.55 4.58

Air Flow, CFM 700 600 730 800

Price, RM (Variance) 1736 (273.25) 2009.25 1847 (474.80) 2321.8

2.0HP 2.5HP


Indoor Unit CC030C MCD530DB CC050C MCD048DB

Outdoor Unit WSS030A WTK530 WSS050A WTK048

Capacity, btu/hr 28000 30000 46500 48000

Noise Indoor, dBA 46 N/A 52 N/A

Cooling EER, Btu/hrW 12.01 N/A 12.15 N/A

Height, inch 14.88 10.16 14.88 16.06

Width, inch 36.57 43.23 51.14 43.23

Depth, inch 21.3 20.91 21.3 29.88

Volume, ft3 6.71 5.31 9.38 12.01

Air Flow, CFM 830 1000 1380 1600

Price, RM (Variance) 2497 (226.65) 2723.65 3228 (879.80) 4107.8

3.0HP 5.0HP


Indoor Unit CC060C MCX060EB

Outdoor Unit WSS060A WTK060

Capacity, btu/hr 54000 60000

Noise Indoor, dBA 53 N/A

Cooling EER, Btu/hrW 13.7 N/A

Height, inch 14.88 24.68

Width, inch 59.02 82.09

Depth, inch 21.3 9.02

Volume, ft3 10.83 10.58

Air Flow, CFM 1530 2000

Price, RM (Variance) 3569 (985.30) 4554.3

6.0HP


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