acson chilled water system-1

Technical Training 2007Technical Training 2007Technical Training 2007

5ACV30 CR5ACV30 CR

5ACV55/75 CR5ACV55/75 CR

5ACV100/135/210 CR5ACV100/135/210 CR

Chilled Water System :Air-Cooled Inverter Mini Chiller


99 System Schematic DiagramSystem Schematic Diagram99 Advantages of Chilled Water SystemAdvantages of Chilled Water System99 Product LineupProduct Lineup99 Design & ApplicationDesign & Application

Content

99 Product FeaturesProduct Features99 Schematic Diagram & ComponentsSchematic Diagram & Components99 Installation & CommissioningInstallation & Commissioning99 Self Diagnosis & TroubleshootingSelf Diagnosis & Troubleshooting99 Smart ManagerSmart Manager99 Selection SoftwareSelection Software99 CompetitorCompetitors Products Comparisons Products Comparison


System Schematic Diagram


System Schematic Diagram

Brazed Plate Heat Exchanger(cooler)

Water

45oF

55oF

Refrigerant Cycle CompressorTXV

Liquid receiver

FCU

Storage Tank

Pump

Chilledwater out

Chilledwater in

Water Circuit

Condenser


Advantages of Chilled Water

System


Quiet Operation

Simple on Site Installation

Versatility inSystem Coupling

Flexible in Installation And Commissioning

Low Cost of Installation

Chilled WaterChilled WaterAdvantagesAdvantages

Long Piping Application

Centralized Control

Multiple ZoneTemperatureControl

Advantages of Chilled Water System


Offers flexibility during installation




No on-site refrigerant charge No time consuming refrigerant balancing

and adjustment Eliminate accident or malfunction Light weight and compact size for ease of

handling



Quiet operation due to minimized outdoor units and mini chiller can be placed far away from room



One to One

One to many



versus

Chilled Water System DX System

Water

PVC

Refrigerant

Copper



Year Round Comfort Multiple Temperature Zone Control

Back To Content


Product Lineup


Product Lineup

Cooling Only/ Heat Pump Model Cooling Only/ Heat Pump Model

Cooling Only/ Heat Pump Model Cooling Only/ Heat Pump Model

Heat Pump

055

MAC- C SeriesM4AC-C Series

120100 150

M5AC- C Series

080060050040030025020000Btu/h

055

MAC- C SeriesM4AC-C Series

120100 150

M5AC- C Series

080060050040030025020000Btu/h


Product Lineup

M5ACV- C Series

210135100075055030000Btu/hM5ACV- C Series

210135100075055030000Btu/h

Heat Pump Model


Design & Application



Understand Clients requirement Application - feasible Installation/service-able Budget Inspection of job site



Site survey Building Load Calculation

- equipment size

Equipment Selection - type of system & equipment

system design:- piping; pump; controls; storage tank;

installation and service maintenance;

water treatment.

cost of equipment operation cost



Where to install the chiller and fan coil units Determine the pipe route and installation / servicing /

maintenance consideration

Building Load estimation for both chiller and Fan coil units (building orientation/size/application,

i.e. pub; restaurant; office.....)

Access to the building for delivery and maintenancelocation of other building services

1. Site Survey



OYL MANUFACTURING CO. SDN BHD COOLING LOAD ESTIMATIONPROJECT NAME : SK Bungalow DATE: 28/2/2001LOCATION : PenthouseAREA = 2000 HEIGHT = 15 NO.OF PEOPLE = 4CFM/PERSON= 15 VENT, CFM = 500 B.F. = 0.15ROOM TEMP = 75 ROOM RH% = TEMP DIFF. (ROOM & OUTDOOR) = 20 MOISTURE DIFF. = 80

GAIN/TD BTU/HR GAIN/TD BTU/HR

OUTDOOR TEMP CORRN= -2 0NE GLASS 600 0.76 45 20,520 22 10,032E GLASS 0.76 106 0 35 0SE GLASS 0.76 97 0 32 0S GLASS 0.76 10 0 8 0SW GLASS 600 0.76 30 13,680 91 41,496 W GLASS 0.76 44 0 132 0NW GLASS 0.76 28 0 75 0 N GLASS 0.76 11 0 11 0SHADED GLASS 0.76 11 0 11 0N WALL 0.49 1 0 13 0NE WALL 200 0.49 53 5,194 17 1,666E WALL 0.49 36 0 15 0SE WALL 600 0.49 16 4,704 16 4,704 S WALL 0.49 1 0 14 0SW WALL 200 0.49 1 98 30 2,940 W WALL 0.49 2 0 39 0NW WALL 600 0.49 1 294 33 9,702ROOF 2,000 0.23 6 2,760 38 17,480ALL GLS TRANSM 1,200 1.13 -2 (2,712) 0 0PARTITION 0.45 -2 0 0 0CEILING 0.3 0 0 0 0FLOOR 0.49 -7 0 -5 0PEOPLE,(S) 4 1 245 980 245 980POWER,KW 4 1 3414 13,656 3414 13,656LIGHTS,WATTS 2,000 1.25 3.414 8,535 3.414 8,535MISC.HEAT (S) 1 1 0 1 0SAFETY % (S) 5 3,385 5,560DT.GN/LK/FAN% 8 0 0OA HEAT(S)*BF 0 0PEOPLE,(L) 4 1 205 820 205 820MISC.HEAT (L) 1 1 0 1 0SAFETY % (L) 10 82 82DUCT LEAK% 8 0 0OA HEAT(L)*BF 4,080 4,080OA HEAT(S)1-BF 0 0OA HEAT(L)1-BF 23,120 23,120

GRAND TOTAL HEAT = 99,196 144,853COOLING TONS = 8.27 12.07ROOM SENSIBLE HEAT = 71,094 116,751TOTAL OA HEAT = 27,200 27,200

4.00PM SEP/MARAREA/QTYITEM FACTORS 10.00 AM SEP/MAR

2. Building Load Estimation



am 4.0 kWpm 3.0 kW

am 3.5 kWpm 5.0 kW

am 3.5 kWpm 5.5 kW

am 3.5 kWpm 2.5 kW

am 4.5 kWpm 3.0 kW

am 4.5 kWpm 3.0 kWam 3.8 kW

pm 3.5 kW

am 9.0 kWpm 8.0 kW

am 3.5 kWpm 5.0 kW

am 3.8 kWpm 3.5 kW

am 3.8 kWpm 3.5 kW

Room 9

Room 11

Room 10

Room 8 Room 7

Room 6Room 5

Room 4

Room 3

Room 2

Room 1

U U 2. Building Load Estimation



am 4.0 kWpm 3.0 kW

am 3.5 kWpm 5.0 kW

am 3.5 kWpm 5.5 kW

am 3.5 kWpm 2.5 kW

am 4.5 kWpm 3.0 kW


pm 3.5 kW

am 9.0 kWpm 8.0 kW

am 3.5 kWpm 5.0 kW

am 3.8 kWpm 3.5 kW

am 3.8 kWpm 3.5 kW

Room 9

Room 11

Room 10

Room 8 Room 7

Room 6Room 5

Room 4

Room 3

Room 2

Room 1

am 4.0 kWpm 3.0 kW

am 3.5 kWpm 5.0 kW

am 3.5 kWpm 5.5 kW

am 3.5 kWpm 2.5 kW

am 4.5 kWpm 3.0 kW


pm 3.5 kW

am 9.0 kWpm 8.0 kW

am 3.5 kWpm 5.0 kW

am 3.8 kWpm 3.5 kW

am 3.8 kWpm 3.5 kW

Room 9

Room 11

Room 10

Room 8 Room 7

Room 6Room 5

Room 4

Room 3

Room 2

Room 1

U 2. Building Load Estimation Diversity Factor



Room a.m. p.m. DXRoom 1 4.0 2.5 4.0Room 2 4.5 3.0 4.5Room 3 4.5 3.0 4.5Room 4 9.0 8.0 9.0Room 5 3.8 3.5 3.8Room 6 3.8 3.5 3.8Room 7 3.8 3.5 3.8Room 8 3.5 4.5 4.5Room 9 3.5 5.0 5.0Room 10 3.5 5.5 5.5Room 11 3.5 5.5 5.5Total 47.4 47.5 53.9Chiller Capacity : 45.7 kWDX unit capacity(total) : 53.9 kWSaving ~ 6.4 kW(11.9 % in this case)

Room a.m. p.m. DXRoom 1 4.0 2.5 4.0Room 2 4.5 3.0 4.5Room 3 4.5 3.0 4.5Room 4 9.0 8.0 9.0Room 5 3.8 3.5 3.8Room 6 3.8 3.5 3.8Room 7 3.8 3.5 3.8Room 8 3.5 4.5 4.5Room 9 3.5 5.0 5.0Room 10 3.5 5.5 5.5Room 11 3.5 5.5 5.5Total 47.4 47.5 53.9Chiller Capacity : 45.7 kWDX unit capacity(total) : 53.9 kWSaving ~ 6.4 kW(11.9 % in this case)

2. Building Load Estimation Diversity Factor


Criteria to select a mini chiller: capacity required water entering condition water leaving condition ambient condition cooling/ heating mode required?

3. Chiller Selection



If the chiller is operate under non standard condition, the capacity can be calculated from the performance characteristic, flow rate and pressure drop then being determined.

Sam

ple

of p

erfo

rman

ce c

hart




Upon chiller units being selected, water flow rate of chiller and pressure drop also need to be determined.

Water flow rate, Liters/Min = Total Capacity, W

70 x Temp. Diff. O C




From Water flow rate, the pressure drop across the chiller units need to be determined for pump selection.

Find the pressure drop from the data table ->




Example 1

Please select a cooling only chiller operate at ambient temperature 35 o C, leaving water temperature 5 o C. Minimum capacity required is 25 kW. Determine the required flow rate and the internal pressure loss.Entering water temperature is 12 o C.




From performance chart, AC100 C selected. The capacity at 35 o C at 5 o C leaving water temperature is 25.90 kW.

Hence the flow rate, liters/min : 2590070 x 5

= 74 liters/min= 1.23 liters/s= 4.44 m3/hr



Solution:


From 4.44 m3/hr and the table above, the pressure drop for AC100C is 47.5 kPa



Solution:


From the total cooling capacity shown in the Table 1, calculate the water flow rate by using the following formula:

Liters/Min = Total Cooling Capacity, W70 x Temperature Rise o C

USGPM = Total Cooling Capacity, Btu/H500 x Temperature Rise o F

4. FCU Selection


Example 2:


Table 1: Total Cooling Capacity

Room am Load, kW pm Load , kW Fan Coil Unit, kWRoom 1 4.0 2.5 4.0 Room 2 4.5 3.0 4.5Room 3 4.5 3.0 4.5Room 4 9.0 8.0 9.0Room 5 3.8 3.5 3.8Room 6 3.8 3.5 3.8Room 7 3.8 3.5 3.8Room 8 3.5 4.5 4.5Room 9 3.5 5.0 5.0Room 10 3.5 5.5 5.5Room 11 3.5 5.5 5.5

4. FCU Selection


Fan Coil units Capacity can be determined by Cooling Capacity Performance Chart as below:


Line A

Line D Line C

Line B

Point 1

Point 4 Point 3

Point 2

Water temperature rise o C

Ente

ring

Wat

er o

C

Total Cooling & Sensible Capacity, kW

Entering Air WB oC

Entering Air DB oC

4. FCU Selection



Line A

Line D Line C

Line B

Point 1

Point 4 Point 3

Point 2

Water temperature rise o C

Ente

ring

Wat

er o

C

Total Cooling & Sensible Capacity, kW

Entering Air WB oC

Entering Air DB oC

Point 1 - Temperature Rise in o C Line A - Determine the temperature risePoint 2 - Entering water temperature o C and entering water temperaturePoint 3 - Entering air temperature (WB) o C Line B - To cross on coil condition, I.e.Point 4 - Entering air temperature (DB) o C WB and DBPoint 5 - Total Cooling Capacity Line C- Intersection point at WB Point 6 - Sensible Capacity determine the total cooling capacity

Line D- Intersection point at DB determineSensible Capacity

4. FCU Selection



Assumption, if cooling capacity of 8.4 kW andentering water at 5 o C, leaving water at 10 o C,then :

Liters/Min = Total Cooling Capacity, W70 x Temperature Rise o C= 8,400 = 24 liters/ min

70 x 5

4. FCU Selection


Solution:


4. FCU Selection


Find pressure drop at this flow rate fromTable of pressure drop


With pre-determine flow rate, pressure drop ofthe fan coil can be determined interpolation methodusing data given in the pressure drop table :

Assumption: Pressure Drop for CC30 CW at flow rate of24 liters/Min = X

X - 7,72 = 24.00 - 20.1411.55 - 7,72 25.21 - 20.14

Water pressure drop, X = 7.83kPa

4. FCU Selection



With pre-determine flow rate, Heating Capacity can be estimated from the heating Capacity Performance Chart

4. FCU Selection



Standard heating capacity is based on EWT at 60 o C and EAT at 21.1 o C, if operating temperature different from the standard, then correction factor need to apply based on table below:

37.8 43.3 45.0 48.8 54.4 60.0 65.5 71.1 76.7 82.2 87.74.4 0.838 0.980 1.021 1.122 1.265 1.406 1.552 1.698 1.845 1.988 2.1347.2 0.771 0.913 0.954 1.055 1.198 1.379 1.485 1.631 1.778 1.920 2.067

10.0 0.700 0.843 0.885 0.986 0.130 1.272 1.417 1.563 1.710 1.853 2.00012.7 0.631 0.773 0.817 0.918 1.062 1.205 1.349 1.495 1.639 1.786 1.93115.5 0.562 0.705 0.748 0.848 0.992 1.137 1.281 1.427 1.572 1.719 1.86518.3 0.493 0.636 0.679 0.779 0.923 1.070 1.212 1.358 1.504 1.650 1.79921.1 0.424 0.567 0.610 0.711 0.855 1.000 1.146 1.290 1.438 1.583 1.73023.9 0.354 0.498 0.541 0.642 0.786 0.932 1.078 1.222 1.369 1.515 1.66426.7 0.284 0.428 0.471 0.573 0.717 0.863 1.008 1.155 1.302 1.449 1.597

WATER ENTERING TEMPERATURE , CHEATING CAPACITY CORRECTION FACTORS

EAT oC

Adjusted heating capacity, W ( @ Nominal air Flow ) = base heating capacity ( @ nominal. 60C EWT, 21.1C EAT) x Heating Capacity Correction Factor

Example at 54.4 o C water entering temperature and 23.9 o C air entering temperature, the correction factor is o.786

4. FCU Selection



2 basic categories of water pipe work systems, i.e.

Close System Open System

5. Water Piping Design



Close System

Pipe installation forms a close circuit minimum water loss in these type of system. Expansion tank / make up water tank is sufficient to top up the loss water




Mini chiller is designed with application of a close water piping system.

Possible to use the unit with an open system by adding a buffer / intermediate tank and pump.




Open System

Pipe works form an open loop. Usuallyuse for cooling tower, formation of alga / bacteria is normal. Water treatment required




If buffer tank being used, Baffle plate install to prevent return water mixing with

chilled water Suitable to use for multiple chiller operation Water tank can be sized accordingly as storage to allow

longer cycled off period for chiller, hence saving energy Care to ensure no air leakage along pump suction line

to prevent air trap - automatic air vent Take care of the water quality, water treatment

required Use only when necessary, i.e. total water volume is

insufficient and need buffer storage to take care of actual requirement / multiple chiller / standard built in pump head insufficient




Open System5. Water Piping Design


Water out

Water inMini Chiller Unit

Return water from fan coil units

Supply water to fan coil units

Secondary pump

TankAir vent

Baffle plate


Type of piping system

Series Diverting Parallel direct return Parallel reverse return




Type of piping system - Series



FCU 1 FCU 2

FCU 4 FCU 3

Water out



Advantages Low pipe cost



Disadvantages Each fan coil cannot be control individually High pressure drop

Type of piping system - Series


Type of piping system - Diverting



Mini Chiller Unit

Water out

Water in FCU 4 FCU 3

FCU 2FCU 1


Advantages Individual control of each fan coils



Disadvantages Only fan coil units with low pressure drops suitable Low water velocity, air vent required Entering water temperature to fan coil units different.

Type of piping system - Diverting


Horizontal Installation

Type of piping system - Parallel Direct Return



Mini Chiller Unit

Water out

Water in

Fan Coil Unit





Mini Chiller Unit

Water out

Water in

Fan Coil Units

Vertical Installation


1st in 1st out Supply and return pipe length uneven Proper balancing of water flow required More economical compare to reverse return type





Horizontal Installation

Type of piping system - Parallel Reverse Return



Mini Chiller Unit

Water out

Water in

Fan Coil Units





Vertical Installation

Mini Chiller Unit

Water out

Water in

Fan Coil Units


1st in - Last out concept

Supply and return pipes equal length simple balancing

Use for fan coil units that have same or nearly the same pressure drop

High rise building required extra length and weight of pipe - not economical





Type of pipes and fittings

There are several types of pipe that normally use in for water piping

Black carbon steel pipe Copper pipe PVC pipe




Black carbon steel pipe

Joint by arc welding; thread; flange with gasket Most commonly used in chiller installation





Copper pipe

High resistance to corrosion and ease installation High cost Can be joint by brazing; soldering; flare joint





PVC pipes

Light weight Corrosion resistance Not suitable for high temperature application Installed with more support(shorter span) UPVC generally up to 60 oC usage CPVC higher temperature application Method to joint : solvent cementing / welding; thread





Galvanized iron(GI) is not recommended as Zinc coating on the GI pipe will have an electrolytic reaction with the copper components in the system, i.e. BPHE; fan coil heat exchanger. The zinc will be sacrificial metal and deposit itselfon the copper surface

Zinc surface slowly eroded Zinc deposit on the copper surface will retard heat transfer

process





Fitting for steel pipe, treaded

90 o elbow tee joint reducer connector union nipple flange





Fitting for Copper pipes - expanded end for brazing or

threaded end

90 o elbow Reducer Tee joint Connector





Fitting for PVC pipes (with treaded end-can joint to steel pipe of fitting

90 o elbow Tee joint Connector Adapter Socket Union Reducer





Type of pipes and valvesValves

- One of the important component in a water piping

system with the following functions:

To isolate a component from the system - enable easy servicing/maintenance

To regulate water flow rate To divert / mix flow direction To prevent back flow To relieve / regulate pressure




Gate valve - to be fully open / fully close; not suitable for regulate or control flow; for isolation / shutoff purposes

Isolation is important for maintenance purposes. The minimum requirement is : Chiller supply and return connection; pump suction and discharge connection; fan coil unit supply and return connection; cooling coil bypass( if 3-way motorized valve is fitted at the coil



Type of pipes and valves


Globe valves - for throttling duty where positive shutoff is required





Ball valve - for throttling duty, used with smaller pipe diameter

Butterfly valve - has low pressure drops; easy and fast operation; can be used for throttling duty





Balancing valve - for throttling duty to regulate water flow rate for balancing purposes. Pressure tapping port provided for pressure drop measurement

Check valve - prevent back flush





Actuators- Automatic valves operate for automatic controller to

control the fluid flow. Common actuators are :

Solenoid valve electric motorized valve pneumatic valve





Solenoid valve - allows wither totally open or close position. A magnetic coil will lifts or drops a plunger to open or close the flow of water





Electric motorized valve - usually this actuator has a built in 24V motor to produce a rotary motion to open or close the valve. Flexible in opening position(depends on external signal); high cost





Pneumatic valve - valve has a flexible diaphragm -operate by injecting air pressure in to the valve to position the valve open / close. High cost





In the chilled water pipe system, automatic control valves used may be either 2-way or 3-way. All three types of actuator above may be used.

2-way valve - water flows into the inlet port and exits from the outlet port. Actuator used to vary the flow rate





3-way valves - 3 ports are available1. Mixing valve

B

A

A + B

2 stream of water blends into 1 stream

2. Diverting valve

A + B

A

B

Split 1 stream into 2 different streams





Installation sample of 2-way valves

FCU

Supply Return




Installation sample of 3-way valves

FCU

FCU

Supply Return

Diverting

Mixing




Wrong Installation sample of 2-way valves



FCU

Mini Chiller Unit

FCU

Problem : both FCU off, solenoid valve off, no water flow. However pump still running, pressure built up, pump problem


Add bypass pipe to relief pressure



Mini Chiller Unit

FCU

FCU

FCU

P

Differential pressure transmitter to monitor theamount of water used. If pressure goes higher than preset value, will activate relief valve and bypass water

Installation sample of 2-way valves pre-cautions





Mini Chiller Unit

FCU

FCU

FCU

P

INV

When differential pressure become higher, the Inverter willslow down the water pump to maintain the heap pressure.If no demand, water pump stop running

Use a variable speed drive for secondary pump


Modify control wiring for chiller and fan coil unit

The above method of 2-way valves installation incur high cost due to extra piping, fittings, pressure transmitter...... There is possible to change the control wiring of the system. Normally when the fan coil unit thermostat cut-off, the power supply to control the 2-way valve will be off. It is possible to run a line from the thermostat to the chiller remote switch whereby when the thermostat cut-off, the chiller and pump will also cut-off.





Installation sample of 3-way valves5. Water Piping Design


Mini Chiller Unit

FCU

FCU

FCU

3-Way valve gives constant flow rate, when no demand,the water bypass through the valve. Energy wastage is the disadvantage.

Use 3-way diverting valves


Other type of valves and fittings

Thermometer - glass thermometers are installed on the inlet and outlet pipes of either the chiller unit or fan coil units. This is to measure the water temperature differential to determine the capacity performance.

Thermometer bulb measuring correct water flow temperature

Thermometer too high up,

stagnant water




Pressure gauge cock - Used to isolate pressure gauges along the water pipe line. When not in use, the valve is closed to prevent prolonged pressurizing to the gauge, and damage the gauge

Pressure gauge

Impulse tubing loop

Gauge cock (ball valve)

Main pipe line





Pressure gauge and thermometer as the previous 2 slides should be included in the design stage - consideration for commissioning. The measuring devices should be installed at the following location :

Main supply and return pipe Main branch supply/return pipe Cooling coils Heating coils Chiller (chilled water side)





Safety relief valve - valve will open when pressure exceed set value to prevent over pressuring the system. Normally used in hot water system. Should be installed near an expansion tank or pump discharge line.

Air vent valve - OYL mini chiller has an automatic air vent located on top of the buffer tank. Air vent valve used to release any trapped air in the tank. Additional air vent should be installed at the highest position of the piping network




Pipe Pipe

Air ventAir vent


Water outlet

Water inlet

Strainer

Strainer - Strainer are a type of filter for water pipe systems. At least one strainer should be installed at the location just before the pump. Strainer should be fitted in the return water connection to chiller prior to brazed plate heat exchanger to prevent dirt/particle trapped within the heat exchanger.





Flow switch - to switch off the chiller unit when low water flow rate is detected in the piping, possible due to : pump failure blocked BPHE accidental closing of valve failure of control valves

Water outlet

Water inlet

BPHE Flow switch





Fan coil pressure loss

Chiller pressure loss

Pipe pressure loss - pipe, fittings & component



System Pressure Loss


Pipe friction looses are dependent on the following factors :

Water velocity Pipe internal diameter Pipe length Type of material - affect the internal wall roughness



Pipe and Fitting Sizing


Water velocity limits are set to take care of noise; erosion andinstallation cost. Recommended guidelines :

Pipe friction loss should be between 1 to 4 ft / 100 ft of equivalent pipe length (100 Pa/m to 400 Pa/m)

Water velocity range for different servicesService Velocity

fps m/sPump discharge 8-12 2.4-3.6Pump suction 4-7 1.2-2.1Drain line 4-7 1.2-2.1Header 4-15 1.2-4.6Riser 3-10 0.9-3.0City water 3-7 0.9-2.1




Calculation of System Loss Step by Step GuideStep 1 - Draw up a schematic layout, c/w chiller; fan coil units and accurately reflect the length of pipe work

Step 2 - Decide the position and numbers of valves, control valves, balancing valves; measuring stations; strainers and mark them on the sketch.

Step 3 - Label each section of the pipe with an identifying letter. Carefully select the pipe route that gives the highest resistance to water flow.

Step 4 - Fill in the water volume flow rate and pipe length for the first section on the pipe sizing chart. Use the pressure loss factor from Friction Loss Chart and equivalent length by using the equivalent length factors from all types of fitting




Calculation of System Loss Step by Step Guide

Step 5 - Enter type of fitting and their quantity, multiply the quantitybe the velocity pressure loss factor by the equivalent length for each type of fitting to get the total fitting equivalent length,

Step 6 - Add the total fitting equivalent length to the straight pipe length to give total pipe length. Multiply the total pipe length by the pipe pressure drop per meter length to obtain a total pressure loss of the pipe section

Step 7 - Repeat step 5 - 7 for other section of pipes. Summarize the total pressure drop for all the section. Take into consideration a minimum of 10% safety factor.

Step 8 - Use the result of step 8 to select the pump




Example 3 Determine the pressure loss of the pipe system below c/w chiller and FCU. If the standard built in pump has external head of 20m, is the pump able to handle the pressure loss?




Pressure loss for copper pipe- close / open system




Pressure loss for steel pipe- close system




Pressure loss for steel pipe- open system




Definition :The equivalent pipe length of a component in the pipe system is the length of a straight pipe which will give the same friction losses as the components itself.

The concept of equivalent pipe length is used in calculating friction losses along the water pipe system, equivalent pipe length can be obtained from tables.



Equivalent pipe length


Fitting : 10 x 90 elbow; 4 tee joint; 2x gate valve; 1 strainer - 1 1/4 steel pipe2 gate valve; 2 tee joint; 1 glove valve 1 1/8 copper

Pressure loss pipe system5. Water Piping Design



Fitting : 10 x 90 elbow; 4 tee joint; 2x gate valve; 1 strainer - 1 1/4 steel pipe2 gate valve; 2 tee joint; 1 glove valve 1 1/8 copper

10 10

15

15

3

5Copper pipe

1 1/8

1 1/4 steel pipe

AC80C

SB75BW5. Water Piping Design



Pressure loss - OYL fan coil unit data

Model Nominal Water flow rate Unit Friction loss at nominal flow rateL/min USGPM PSI (unit internal components)

SB75BW 57.00 15.08 6.08SB100BW 73.48 19.44 1.83SB125BW 97.49 25.79 2.46

Please refer to relevant technical manual AFCU-2004, page 70




Pressure loss - OYL mini chiller data

Note : Unit internal losses take care of friction loss through Brazed plate heat exchanger (BPHE); internal pipe work; pump fittings, flow switch, etc.Please refer to relevant technical manual




Steel pipe 1 1/4 diameter :

Flow rate : 15.08 usgpm (57.00 Liters/min)Straight pipe length : 55 x 2 = 110Equivalent length for fittings : 10 x 3.3 = 33 (elbow)

4 x 2.3 = 9.2 (tee joint)2 x 1.5 = 3.0 (gate valve)1 x 9.0 = 9.0 (strainer)

Total equivalent pipe length = 164.2

From Friction loss for closed piping system, at 15.08 usgpm, forsteel pipe, the friction loss is 3.8 / 100 of pipe, hence friction losteel pipe = 3.8 x 164.2/100 = 6.24






Total external pipe and fitting loose = 11.87

Copper pipe 1 1/8 diameter :

Flow rate : 15.08 usgpmStraight pipe : 3x2 = 6 Equivalent pipe length for fitting : 2 x 1.4 = 2.8(gate valve)

2 x 0.9 = 1.8 (tee joint)1 x 22 = 22 (globe valve)1 x 1 = 11 x 1.5 = 1.5

Total equivalent pipe length copper : 33.1friction loss for copper pipe(1 1/8 at 15.08 usgpm) = 17/100hence 33.1 gives : 17 x 33.1/100 = 5.63


Fan coil loose : 6.08

mini chiller internal loose : 8.7

Total external pipe and fitting loose = 11.87

Total system friction loose : 6.08+8.7+11.87 = 26.65

= 8.125m




Pump is one of the fundamental component in the system. It

circulates water through all the components in the system.

Pump is a built in component in OYL mini chiller. Basic

understanding about the pump characteristic is important.

6. Pump Selection



Primary - secondary pump

If the built in pump in the mini chiller is not able to deliver the head pressure required to the load even in a close loop system :

Change the existing pump to a higher head pump Install a booster pump - primary - secondary pump system

6. Pump Selection




6. Pump Selection


Water out

WaterinMini Chiller Unit

Booster pump (secondary)

Bypass loop

A

B

Fan Coil Units

Built in pump(primary)


Disadvantages of this system Extra cost for pump Unused bypass chilled water - wastage

Cautions Bypass loop short(but sufficient to prevent turbulence) to

minimize pressure loss between the entry and exit point of loop

Do not use any valve in the bypass loop

6. Pump Selection




Case 1: Capacity of Primary Pump = secondary pumpno flow in the by pass loop, water temperature entering the load(FCU) is equal to water temperature leaving the chiller

Case 2: Capacity of primary pump > secondary pumpa net flow down the loop and return to chiller unused. A become diverting T joint and B become mixing T: Water temperature entering FCU = water temperature leaving chiller, however water entering chiller will be colder due to unused chilled water bypass back through B

6. Pump Selection




Case 3: Capacity of primary pump < secondary pump

a net flow up the loop from B. A become a mixing point and B

become diverting T. Water temperature entering FCU will be in

between the water temperature leaving the chiller and the water

temperature entering Chiller

6. Pump Selection




Primary - secondary pump in series6. Pump Selection


Water out


FCU

Built in pump(primary)

Booster pump (secondary)


This installation is not recommended :

risky - wrong pump sizing can caused damage to pump

if this design need to be used, primary pump capacity must be equal to the secondary pump, otherwise :

cavitations problem to the smaller pump pressure drop across pump high head loss - harmful to the chiller

6. Pump Selection


Primary - secondary pump in series


7. Multiple Chiller Selection


Primary - secondary pump in series

In the cases of multiple chiller need to be used,there are few possible installation method :

Common supply and return headers Primary - secondary system Common tank system


Common supply and return headers7. Multiple Chiller Selection


Chiller 1

Chiller 2

Chiller 3

Check Valve

Supply Header

Return Header

Chilled water supply

Chilled water return




Chiller 1

Chiller 2

Chiller 3

Check Valve

Chilled water supply to FCU

Chilled water return from FCU

Common supply and return headers


Most common and preferred Low installation cost Chiller set at different return water temperature - load staging Check valve to prevent back flush of water Drawbacks proper balancing of water flow rate through each chiller is

crucial Any chiller off, water flow rate to the FCU will be affected.

To overcome this, it is necessary to wire the chiller controls for continuos pump running as long as one fan coil is in operation

One supply line, less flexibility in water distribution control, i.e. the highest pressure losses zone might be affected





Balancing valves must be installed a each supply branch to ensure the proper flow rate through each chiller and header design is important

Header Header





Common supply and return line

No common header used, higher pressure drop along common pipe lines - can use larger pipe size

at this common line to reduce pressure lost.

Proper balancing is crucial

1st in last out arrangement at the supply and return lines is useful to reduce the problem of distribution




Primary - secondary pump system7. Multiple Chiller Selection


Chiller 1

Chiller 2

Chiller 3

Check Valve


Chilled water returnBypass Loop

Secondary Pumps

Primary Pump


Chiller of different capacities can be installed together without much balancing

Balancing valve required

Secondary pump alone handle the flow and pressure requirements of FCU - if one of the primary pump off,

the water supply to FCU not affected



Primary - secondary pump system




Primary - secondary pump system

Chiller 1

Chiller 2

Chiller 3

Check Valve


Chilled water return

Secondary Pumps

Auxiliary tank

Primary Pump


Common tank system - Open System7. Multiple Chiller Selection


Chiller 1

Chiller 2

Chiller 3

Chilled water to FCU

Secondary Pumps

Primary Pump

Tank

Return from FCU


Each chiller and secondary pump forms own pipe circuit Common tank act as buffer storage tank No check valve required, normal globe valve is sufficient

to ensure proper water flow

Tank at higher level - to allow gravity feed of water to the chillers and pumps

Refer to earlier slide for open system for all cautions during installation and operation



Common tank system - Open System


Multiple chiller-single fan coil load with multiple circuits - common header



Chiller 1

Chiller 2

Chiller 3

Check ValveSupply Header

Return Header

Circuit 2

Circuit 1

Circuit 3




Multiple chiller-single fan coil load with multiple circuits - common header

Chiller 1

Chiller 2

Chiller 3

Circuit 2

Circuit 1

Circuit 3


Minimum compressor run time : 3 minutes(PCB design)

Minimum off time of compressor : 4 minutes(PCB design)~ compressor possible cycle on/off 8 times/hour.

Total volume of water in the system must be able to pull-down by 5 C temperature within 3 minutes

Total volume of water = volume of storage tank + volume of pipe length + volume of expansion tank

Water Volume = Time * flow rate for 5 C Temp. Diff. Water Volume = 3* flow rate (liters/min)

8. Water Storage Tank and Expansion Tank



Volume = Time * flow rate for 5 o C Temp. Diff. Volume = 3* flow rate (liters/min)

Example : A mini chiller has a cooling capacity of 40,000 Btu/hr (11.72 kW)

Flow rate USGPM = Capacity, Btu/hr500 * 9

or Flow rate Liters/min = Capacity, W70 * 5

Flow rate = 11720/350 = 33.6 liters/min

Volume of system = 3 * 33.6 = 100.8 liters

Assuming the storage tank capacity is 1/3 of the total system water volume, storage tank capacity = 100.8/3 = 33.6 liters




For simple calculation, the following tables can be used to estimate the volume of water in a system by simply multiply the length of pipes with the factor:Pipe type Pipe Size Water Volume, liters/minSteel, SCH. 40(ST) 1/2 0.196

3/4 0.3441 0.5581 1/4 0.9651 1/2 1.3132 2.1652 1/2 3.098

Copper, type L 1/2 0.0945/8 0.1513/4 0.2257/8 0.3121 18 0.5321 3/8 0.8111 5/8 1.1482 1/8 1.9972 5/8 3.079

PVC, DIN 8062 20mm 0.22725mm 0.35332mm 0.58140mm 0.90850mm 1.425




Expansion tankExpansion tank provide a space into which water can expand or from which it can contract as the water go under volumetric changes with respect to temperature change. This device is compulsory in heat pump units.

Air

Water

Tank

Diaphragm

Threaded end

Tee Joint

Pump suction lineWater Flow from Mini Chiller




Spacing between the plates is small, no debris, fouling or scaling in the system is important to ensure no restrict in water flow and thus performance not affected.

Strainer along water suction line will remove debris like sand, metal debris, etc..

It is good practice to install filter at the make up water supply line.

Filter elements required periodical service to remove trapped particles.

Flushing the pipe with water during initial start up and commissioning of the min chiller is necessary

9. Water Treatment



Fouling refers to the tendency of water form a film on the heat transfer surfaces. Fouling can be organic or inorganic surface fouling.

Organic fouling includes microbiological growth. Algae may also form on these surfaces. This is more significant in open system

Scaling is inorganic fouling. It is normally caused by deposit inorganic salts

Symptoms: sudden increase in pressure drop and gradual drop in heat transfer performance

Remedy : Chemical cleaning

9. Water Treatment



Organic fouling can be removed by use of alkaline cleaningagent like sodium hydroxide at 5% concentration. Refer to chemical manufacturer for more details instruction. Make sure the excess chemical is fully clean up from the system

Inorganic fouling most commonly need acidic based cleaningagent. Mineral acids has strong ability to dissolve scales, but attack/corrode stainless steel and copper parts, hence is not recommended. Organic acids at 2 - 5% concentration is more ideal when used to clean BPHE.

Refer to chemical manufacturer recommendation on the dosage requirement. Upon completion, flush with clean water to remove excess acids.

It is recommended that the water to be replaced at least once a year to prevent fouling on the BPHE

9. Water Treatment



Glycol Solutions

Entering water temperature - operating range

EWT 0C EWT 0C Max EWT 0CFactory Setting Minimum maximum

Cooling Mode 12 3 15Heating Mode 40 35 50Antifreeze 2 -4 3

9. Water Treatment



SW2 Setting(for cool mode)

SET TEMP. SW20C SW2-3 SW2-2 SW2-1

Set by VR3 off off off3 off off on4 off on off5 off on on6 on off off7 on off on8 on on off9 on on on

If DIP switch is set to (off,off,off), the set temperature is determineby VR3 setting, otherwise setting above will override the VR3 setting

9. Water Treatment


Glycol Solutions


For Commissioning, it is recommended to observeand adjust the setting if necessary :

For cooling mode, press SW1 once in PCB Green LED will blinks for few seconds Adjust VR3 to the required water entering temperature by using

suitable tools If glycol added, the entering water temperature (3 0C-9 0C) can

be set by adjusting DIP switch (SW2) For heating mode, press SW1 twice, red LED will blinks for few

seconds Adjust VR1 to set the required water temperature for heating

mode VR2 is adjusted to set antifreeze temperature

9. Water Treatment


Glycol Solutions


If sensor setting has been adjust for process cooling - to operate at lower temperature, precaution must be taken to prevent water freeze up. For sub zero application, the water must mix with anti freeze glycol solution.

2 commonly used glycol : ethylene glycol and propylene glycol. Ensure the quantity mixed with water is sufficient to cater for the operating temperature requirement. The more glycol added, the capacity loss is higher.

Make sure water pump is on all the time to ensure continuous water flow through BPHE to prevent formation of ice.

9. Water Treatment


Glycol Solutions


Correction factors with Glycol added to water

Glycol % Capacity Water flow Pressure drop10 0.990 1.015 1.0620 0.980 1.040 1.1230 0.970 1.080 1.1840 0.965 1.135 1.24

9. Water Treatment


Glycol Solutions


9. Water Treatment


Glycol Solutions


Pipe being insulated for the following purposes :

Prevent heat gain / loss from the water in the pipe Prevent condensation when chilled water flow in the pipe Prevent injury due to hot water flow in the pipe

To do a calculation of insulation thickness, one must know :

Insulation material thermal conductivity coefficient (K) Pipe size Air condition at the site of installation (Dry bulb and humidity) Convective heat transfer coefficient (H) A simplify spread sheet is provided to estimate the insulation

thickness

10. Pipe Insulation Requirement



PIPING INSULATION THICKNESS CALCULATION:

Air condition:DB/C 25 Dew pointRH/% 75 DP/C 20.26

Pipe specification:Pipe dia. 1.25 in 31.8 mmRadius, r1 15.879 mm

Pipe surface temperature/C 7

Insulation material:

Material: ArmarflexThermal conductivity, k 0.0374 W/mK

Surface convective heat transfer 9 W/m2Kcoefficient, h

Insulation selection:Calculated insulation sizer2 25.181 mm

Insulation thickness 9.3 mm(Minimum) 0.4 in

USE THE NEXT SIZE THICKNESSAVAILABLE OR THICKER FORSAFETY FACTOR




Few application samples will be provided, however with the following considerations:

The option Alarm LED from terminal AL1 and AL2 in mini chiller is meant to be installed into the external control switch board - to indicate if an abnormal operation has occur. The PCB will give out a signal to light up the LED when any of the protection devices trip.

The option Remote Switch may be located at a convenient place for easy access to the user. It may be placed inside the switchboard. It can also act as an emergency switch to stop the chiller

The power supply for the fan coil units are separated from the mini chiller



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