air conditioning the grundfos way

Grundfos FLOW THINKING

Air conditioningthe

Grundfos Way


Q100%25%

H

0 20 40 60 80 100

100

80

60

40

20

0

Flow in %Eff

ect i

n % 1.

2.

3.4.5.

Obtainable energy saving

1. Constant pressure2. Constant diff. pressure3. Proportional diff. pressure (calculated)4. Proportional diff. pressure (measured)5. Temperature control


Optimized operation cost often means LOWER ENERGY COSTAn effective way of checking the profitability of the pump system is to use Life Cycle Cost analysis. This will show not only the ”energy cost” but all costs related to the pump system.

Optimized operation cost

The result of the analysis can also show the pay-back time of a speed controlled solution compared to a traditional constant speed pump.

Result of Life Cycle Cost analysis


Controls For Variable Speed Application

• VARIOUS OPTIONS e.g.

• Pumps with built-in Frequency Converter & PLC…• Pumps with External Frequency Converter & External

PLC…


Chillers

Primary Pumps

Secondary Pumps

Load

Balancing Valve 2 – Way Valve

Panel with PLC & VFD`s

Air -Separator

Com

mon

Primary - Secondary Circuit With Variable Speed Secondary Pumps


Why Do We Need Variable Speed Secondary and Tertiary Pumps ???

•For Energy Saving….

•For better & smooth operation….


How Do We Achieve This Reduction In Power Consumption ??

By Using Variable Frequency Drive and Logic controller with the Secondary Pumps….


Basic Law which helps in achieving this – Affinity law

1. Flow2 = Flow1(Speed2/ Speed1)

2. Head2 = Head1(Speed2/ Speed1)2

3. BKW2 = BKW1(Speed2/ Speed1)3

If Diameter of Impeller is to be trimmed then instead of speed the same can be used in above formulas.


PFU

PMU

4 – 20 mA

Set Value

From Field Sensor (DPT)

PFU – Pump Functional Unit

PMU – Pump Management Unit

Basic Concept

Output

To

VFD/Pump


Opening/Closing of 2- Way Valve-Signal from the sensor, installed at load

regulates the valve opening & closing.

-This way differential across 2-way valve also

changes & accordingly output signal is given to

PLC.

Temperature Sensor

Load

Output to PFU from DPT


Chillers

Balancing Valve

Load

Primary Pumps

Com

mon Secondary

Pumps

Panel with PLC & VFD`s

DPT

An Example


APPROVAL FROM INTERNATIONAL AGENCIES

Approval from – CE, U/L Conforms to - Electromagnetic compatibility (89/336/EEC) to standard EN 50 081 – 1 and EN 50 082 – 2 and Electrical equipment design 73/23/EEC standard to EN 60 204-1.


Tertiary Pumping

In Air-conditioning Systems


Air conditioning systems

Chiller

Colling tower Cooling ceiling

Cooling surface

Secondarypumps

Heat recovery Fan coils M

Buffer tank

M

M

Primarypump

Pressureholding

Improved balancing by Tertiary pumps


psecondary

pumpp:

control valve

Airunit

Airunit

Airunit

Fancoils

Fancoils

Buffer tank

M M M M

Distance/pressure profile

psecondary

pump

p: pipes,control valvesfan coils etc.

Airunit

Airunit

Airunit

Fancoils

Fancoils


System with only secondary pumps

System with tertiary pumps

Buffer tank

Q

H

Qmax.

Max.p

Q

H

Qmax.

Max.p

p: connection point

p: connection point

M

Tertiary pumps


psecondary

pumpp:

control valve

Airunit

Airunit

Airunit

Fancoils

Fancoils

Buffer tank

M M M M


Hybrid System

Q

H

Qmax.

Max.p p: connection point

M

Tertiary pumps


Tertiary Systems….Few points

Tertiary pumps can be Variable speed……. Tertiary pumps can be fixed speed also…. Mixing loops are not mandatory in tertiary

loops… But mixing loops add flexibility in the overall air-

conditioning system… Tertiary pumps PLC should be controlled by DPT

signal (if variable speed panel is used)…


Tertiary Systems….Few points

For Secondary pumps only friction loss upto zone termination point should be taken care…

For Tertiary pumps friction loss of valves, coil etc should be taken care….


Advantages with Tertiary pumps

1. Smaller secondary pumps, motor and drives2. Lower differential pressure in all connection points3. Lower operation cost4. Higher flexibility if the system have to be redesigned5. Each to find the right location for the p sensor6. Minimized risk of “over sizing” secondary pumps


Mixing LoopsIn Air-conditioning

Systems


• Why mixing loops• Where can mixing loops be used• Different types of mixing loops• Design• Function• Energy saving by using mixing loops

Mixing loops


pp p p pPressureprofile

In large systems the diffential pressure will decrease/increase dependingupon the distance from the pump, and not reflect the actual need.

The source of unbalance in a system

Why mixing loops – Increase of hydraulic balance in large/Tertiary/district heating or cooling systems


Will adapt to use of the building:HolidaysLoad of the floor

Systems with zone division

Floor divided

Facade dividedWill adapt to weather conditions:SunWind

Why mixing loops – Increase of the control of different part of a building


In particulary District/large cooling systems a correct differetial temperature reduces the operation cost.

t 5oC

t 5oC

t 5oC

t 5oC

t 5oC

t 5oC

= m3/hkW x 0,86t

High differential temperature means lower flow.

Formula for calculating the flow in a cooling system

Why mixing loops – Correct differential temperature at the chiller return


Sun radiation

Electrical equipment

Other rooms

Other rooms

Light LightPeople

Wind

External parameter which haveinfluence on the cooling/heat demand

Internal parameter which haveinfluence on the cooling/heat demand

Why mixing loops – parameters which influence in the indoor temperature


•Heating systems

Where can mixing loops be used

•Heating systems•Radiator systems•Air handling units•Floor heating

•District Heating/Cooling•Building connection

•Cooling systems•Fan coils•Air handling units•Cooling ceilings

All circulating systems where there is a demand for improving the balance and controlling the temperatures

For Primary-Secondary as well as Secondary-Tertiary


System 1 System 2 System 3 System 4 System 5

Hydraulic separationTemperature control

InvestmentOperation cost LOW LOW LOW HIGH HIGH

NO

NO

MIDIUM

YES

YES

MIDIUM

NO

YES

HIGH

YES

YES

HIGH

YES

YES

HIGH

Secondary side

Tertiary side

tO

Load

tf

M

tO

Load

tf

M

tO

Load

tf

M

tO

Load

M

tf

tO

Load

M

Mixing loops overview

tr tr tr tr


Secondary side Tertiary side

M

Tf

Shut-off valve

Control valve

to

Thermometer

Out-door temperature sensor Loop

controllerFlow

temperature sensor

Non-return valve

Strainer Shut-off valve

Circulator pump

Design

Tr

Returntemperature sensor


By adding more or less chilled water to the tertiary side the Loop Controller is adjusting the flow temperature based on outdoor, zone supply and return temperature.

Loop controller

tto

M

Function of the Loop controller

tr

tf


Conclusion:1. Full hydraulic balance in the system:

It will also be possible to change the cooling/heating system in one of the buildings without disturbing the balance in in the other buildings.

2. Reduced power consumption: Experiences shown a reduction of chiller power consumption when

mixing loops are installed.

3. Reduced pump energy consumption: Can be reduced to up to 30-40%

Energy consumption in system with mixing loops pumps.


Conclusion:4. Better zone control:

Mixing loop will help in achieving better individual zone control.

5. Smaller Secondary pumps: In case of Primary-secondary-tertiary systems smaller secondary

pumps are used

6. Suitable for any application: Can be used for Primary-secondary-Tertiary, Primary-Tertiary as well as Primary- secondary

Energy consumption in system with mixing loops pumps.


THANK YOU

air conditioning the grundfos way

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