Danfoss How to design balancing and control solutions for energy efficient hydronic applications in residential and commercial buildings Application guide

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Application guide

Hydronic applications

Commercial

Hydronic applications

How to design

balancing and control solutions for

energy ecient hydronic applications

in residential and commercial buildings

applications with detailed descriptions about the investment, design, construction and control

Residential

Mixing loop

AHU application

AHU heating

AHU application

AHU cooling

hbc.danfoss.com

Chillers applications Boilers applications Hot water

Content structure in this guide

1. Hydronic applications

1.1 Commercial

1.1.1 Variable ow

1.1.2 Constant ow

1.2 Residential

1.2.1 Two-pipe system

1.2.2 One-pipe system

1.2.3 Heating – special application

Typical page shows you:

Chapter

Schematic drawing

2. Mixing loop

3. AHU applications

3.1 AHU applications heating

3.2 AHU applications cooling

4. Chillers applications

5. Boiler applications

6. Hot water applications

Recommendation Type of solution

7. Glossary and abbreviations

8. Control and valve theory

9. Energy eciency analyses

10. Product overview

Application

General system description

Danfoss products

Performance indicators

Application details

Introduction Notes

Return of investment

poor exellent

Design

acceptable

Designing HVAC systems is not that simple. Many factors need to be considered before making the nal decision about the heat- and/or cooling load, which terminal units to use, how to generate heating or cooling and a hundred other things.

This application guide is developed to help you make some of these decisions by showing the consequences of certain choices. For example, it could be tempting to go for the lowest initial cost (CAPEX) but often there would be compromises on other factors, like the energy consumption or the Indoor Air Quality (IAQ). In some projects the CAPEX might be the deciding factor but in another ones it is more about energy eciency or control precision, therefore it diers from project to project. We collected the most important information concerning a particular solution on a single page with clear indications what consequences can be expected when certain choices are made.

The aim of this guide was not to cover each and every application because that would be impossible. Every day, smart designers come up with new solutions that might be relevant only to one specic problem or that is solving new problems. That is what engineers do. The drive for greener, more energy-friendly solutions is creating new challenges every day, so there are always some new applications. In this particular guide we will nd to cover the applications that are the most common.

Danfoss also has many competent people available that can support you with specic challenges or that can support you with calculations. Please contact your local Danfoss oce for support in your native language.

We hope this guide will help you in your daily work.

Each application shown here is analyzed for four aspects:

Return on Investment, Design, Operation/Maintenance, Control

Return of investment

poor exellent

Design

poor exellent

acceptable

All of them are marked as:

Technically and economically optimized solutions as recommended by Danfoss. This solution will result in eciently operating systems.

Depending on the situation and the particularities of the system this will result in a good installation. However, some trade-os are made.

Operation/Maintenance

poor exellent

Control

poor exellent

Recommended

Acceptable

acceptable

This system is not recommended since it will result in expensive and inecient systems or the Indoor Air Quality is not ensured.

Not Recommended

Table of Contents

Content structure in this guide 2

Typical page shows you: 2

Introduction 3

1. Hydronic applications

1.1Hydronic applications – commercial buildings 6

1.1.1 Commercial - Variable ow

1.1.1.1 Variable ow: Pressure Independent Control (PICV) with ON/OFF actuator 8

1.1.1.2 Variable ow: Pressure Independent Control (PICV) with proportional control 9

1.1.1.3 Variable ow: Pressure Independent Control (PICV) with digital actuator 10

1.1.1.4 Variable ow: Flow limitation (with ow limiter) on terminal unit with ON/OFF or modular actuator 11

1.1.1.5 Variable ow: Dierential pressure control with ON/OFF or modulation 12

1.1.1.6 Variable ow: Shell and Core installation for Oces and Shopping malls* 13

1.1.1.7 Variable ow: Manual balancing 14

1.1.1.8 Variable ow: Manual balancing with reverse return 15

1.1.1.9 Variable ow: Four-pipe Changeover (CO6) for radiant heating/cooling panels,

chilled beams, etc. with PICV control valve 16

1.1.1.10 Variable ow: Two-pipe heating/cooling system with central changeover* 17

1.1.2 Commercial - Constant ow

1.1.2.1 Constant ow: 3-way valve with manual balancing (in fan-coil, chilled beam etc. application) 18

1.1.2.2 Constant ow: 3-way valve with ow limiter on terminal units (fan-coil, chilled beam etc. application) 19

1.2 Hydronic applications - residential buildings

1.2.1 Residential - Two pipes system

1.2.1.1 Two-pipe radiator heating system – risers with, thermostatic radiator valves (with presetting) 20

1.2.1.2 Two pipe radiator heating system – risers with, thermostatic radiator valves (without presetting) 21

1.2.1.3 Pressure Independent Control for radiator heating system 22

1.2.1.4 Subordinated risers (staircase, bathroom, etc.) in two- or one-pipe radiator heating system without thermostatic valve 23

1.2.1.5 Δp control for manifold with individual zone/loop control 24

1.2.1.6 Δp control and ow limitation for manifold with central zone control 25

1.2.2 Residential - One pipe system

1.2.2.1 One-pipe radiator heating system renovation with automatic ow limitation

and possible self-acting return temperature limitation 26

1.2.2.2 One-pipe radiator heating system renovation with electronic ow limitation and return temperature control 27

1.2.2.3 One-pipe radiator heating system renovation with manual balancing 28

1.2.2.4 One-pipe horizontal heating systems with thermostatic radiator valves, ow limitation

and return temperature self-acting control 29

1.2.3 Residential - Heating - special application

1.2.3.1 Three-pipe, at station system; Δp controlled heating and local DHW* preparation 30

2. Mixing loop

2.1 Mixing with PICV – manifold with pressure dierence 31

2.2 Injection (constant ow) control with 3-way valve 32

2.3 Mixing with 3-way valve – manifold without pressure dierence 33

3 AHU applications

3.1 AHU applications - heating

3.1.1 Pressure Independent Control (PICV) for cooling 34

3.1.2 3-way valve control for cooling 35

3.2 AHU applications - cooling

3.2.1 Pressure Independent Control (PICV) for heating 36

3.2.2 3-way valve control for heating 37

3.2.3 Keep proper ow temperature in front of AHU in partial load condition 38

4. Chillers applications

4.1 Variable primary ow 39

4.2 Constant primary variable secondary (Step Primary) 40

4.3 Constant primary and variable secondary (Primary Secondary) 41

4.4 Constant primary & secondary (Constant Flow System) 42

4.5 District cooling system 43

5. Boiler applications

5.1 Condensing boiler, variable primary ow 44

5.2 Traditional boilers, variable primary ow 45

5.3 System with manifolds de-couplers 46

6. Domestic hot water

6.1 Thermal balancing in DHW circulation (vertical arrangement) 47

6.2 Thermal balancing in DHW circulation (horizontal loop) 48

6.3 Thermal balancing in DHW circulation with self–acting disinfection 49

6.4 Thermal balancing in DHW circulation with electronic desinfection 50

6.5 DHW* circulation control with manual balancing 51

7. Glossary and abbreviations 54

8. Control and valve theory 56

9. Energy eciency analyses 65

10. Product overview 75

Commercial

Hydronic applications

Residential

Hydronic applications

Mixing loop

Hydronic applications – commercial buildings

Variable flow* systems

1.1.1.1 - 1.1.1.6**

Hydronic applications can be controlled and balanced based on a lot of dierent type of solutions. It is impossible to nd the best one for all.

We have to take into consideration each system and its specic to decide what kind of solution will be the most ecient and suitable.

All applications with control valves are variable ow* systems. Calculation is generally done based on nominal parameters but during operation ow in each part of the system is changing (control valves are working). Flow changes result in pressure changes. That’s why in such case we have to use balancing solution that allows to respond to changes in partial load.

Pressure Independent Control

Notes

AHU application

Chillers applicationsBoilers applicationsHot water

AHU heating

Dierential Pressure Control

AHU cooling

Manual Balancing

The evaluation of systems (Recommended/Acceptable/Not recommended) is principally based on combination of 4 aspects mentioned on page 3 (Return on investment/Design/ Operation-Maintenance/Control) but the most important factors are the system performance and eciency.

On application above the manual balanced system is Not recommended because the static elements are not able to follow the dynamic behaviour of variable ow* system and during partial load condition huge overow occurs on control valves (due to smaller pressure drop on pipe network).

The dierential pressure controlled system performs much better (Acceptable) because the pressure stabilization is closer to control valves and although we still have manual balanced system inside the dp controlled loop, the overow phenomenon mitigated. The eciency of such system depends on location of dierential pressure control valve. The closer it is to control valve, the better it works.

The most ecient (Recommended) system we can have is using PICV (pressure independent control valves). In this case the pressure stabilization is right on the control valve, therefore we have full authority* and we are able to eliminate all unnecessary ow from the system.

*see page 54-55

** applications below

Commercial

Hydronic applications

Hydronic applications – commercial buildings

Variable flow* system: PICV – ON/OFF vs modulating vs smart control

1.1.1.1 - 1.1.1.3**

All these applications base on PICV (Pressure Independent Control Valve) technology. It means the control valve (integrated into the valve body) is independent from pressure uctuation in the system during both full, and partial load conditions. This solution allows us to use dierent types of actuators (control method)

• With ON/OFF control, the actuator has two positions, open and closed

• With modulation control the actuator is able to set any ow between nominal and zero value

• With SMART actuator we can ensure (above modulation control) direct connectivity to BMS (Building Management System) to use advanced functions such as energy allocation, energy management etc.

Controlers

Notes

Hydronic applications

Residential

Mixing loop

AHU application

AHU heating

PICV & ON/OFFPICV &

ControlerControler

modulating

PICV technology allows us to use proportional or end point (based on Δp sensor) pump control

The above mentioned control types strongly aect on overall energy consumption of systems.

While ON/OFF control ensures either 100% or 0 ow during operation, the modulation control enables to minimize the ow rate through on terminal unit according real demand. For example, to the same 50% average energy demand we need around 1/3 of ow rate to modulation control, compared to ON/OFF control. (You can nd more details in chapter 9) The lower ow rate contributes to energy saving* on more levels:

• Less circulation cost (fewer ow needs less electricity)

• Improved chiller/boiler eciency (less ow ensures bigger ΔT in the system)

• Smaller room temperature oscillation* ensures better comfort and denes the room temperature setpoint

PICV &

SMART actuator

T T

AHU application

AHU cooling

Chillers applications Boilers applications Hot water

The SMART control – over the above mentioned benets - enable to reduce the maintenance cost with remote access and predictive maintenance.

*see page 54-55 ** applications below

Commercial

FAN COIL UNITS (FCU)

Hydronic applications

Recommended

1.1.1.1

CoolingHeating

Variable ow: Pressure Independent Control (PICV) with ON/OFF actuator

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

1. Preasure Independent Control Valve (PICV)

2. Room temperature Control (RC)

Balancing of the terminal unit by pressure independent valves. This will ensure the right ow at all system loads, regardless of pressure uctuations. ON/OFF control will cause uctuations in the room temperature. The system will not be operating optimally because the ΔT is not optimized.

PICV-1

CHILLED PANELS

PICV-2

Danfoss products:

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

Performance

Return of investment

poor acceptable

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

PICV-1: AB-QM 4.0 + TWA-Q PICV-2: AB-QM 4.0 + AMI-140

Explanation

Return of investment

• Reduction of components by eliminating the need for balancing valves

• Lower installation cost due to simplied installation

• The chillers and boilers operate eciently but not optimally because the ∆T is not optimized

• Handover of the building can easily be done in phases

Design

• Easy selection of valves based only on the ow requirement

• No Kv or authority* calculation is needed, the calculation is based on ow demand

• Perfect balance at all loads

• Proportional pump control is applicable and the pump(s) can be optimized* easily

• Min available ∆p demand on the valve can be taken for calculating the pump head

Operation/Maintenance

• Simplied construction because of a reduction of components

• Set and forget, so no complicated balancing procedures

• Fluctuating room temperature, so some occupant complaints can be expected

• Low operational and upkeep cost, so occupants may experience discomfort

• Good but reduced eciency in chillers, boilers and pumping because of a sub-optimized ∆T in the system

Control

• Temperature uctuations *

• No overows*

• Pressure independent solution, so no pressure changes do not aect control circuits

• Low ∆T syndrome* is unlikely to happen

*see page 54-55

CoolingHeating

FAN COIL UNITS (FCU)

Variable ow: Pressure Independent Control

Hydronic applications

Commercial

Recommended

(PICV) with proportional control

PICV-1

0-10VRC

CHILLED PANELS

PICV-2

Danfoss products:

BMS

1.1.1.2

1. Pressure Independent Control Valve (PICV)

2. Building Management System (BMS) or Room temperature Control (RC)

Temperature control of the terminal unit is ensured with pressure independent valves. This will ensure the right ow at all system loads, regardless of pressure uctuations. The result will be stable* and precise room temperature control to ensure a high ΔT and prevent actuators from hunting.

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

PICV-2: AB-QM 4.0 + AME 110 NLPICV-1: AB-QM 4.0 + ABNM A5

Explanation

Return of investment

• Reduction of components by eliminating the need for balancing valves

• Lower installation cost due to simplied installation

• Signicant energy savings* due to optimal working conditions for all components

• Handover of the building can easily be done in phases

Design

• Easy selection of valves based only on the ow requirement

• No Kv or authority* calculation is needed, ow presetting calculation based on ow demand

• Proportional pump control is applicable. The pump(s) can be optimized easily *

• Suitable for BMS applications to monitor the system and reduce energy usage

Operation/Maintenance

• Simplied construction because of a reduction of components

• Set and forget, so no complicated balancing procedures

• Good control at all loads, so no complaints by occupants

• Low operational and upkeep cost

• High comfort (building classication*) because of precise ow control at all loads

• High eciency in chillers, boilers and pumping because of the optimized ∆T in the system

Control

• Perfect control because of full authority *

• No overows* at partial system loads

• Proportional control minimizes the ow circulation and optimizes the pump head

• Pressure independent solution, so pressure interdependency of the control circuits

• No low ∆T syndrome *

Applicable for all terminal units, included AHU (see page 34, 36)

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

AHU heating

Chillers applications Boilers applications Hot water

AHU applications

*see page 54-55

Commercial

Hydronic applications

Residential

Hydronic applications

Recommended

1.1.1.3

I/O

BMS

CoolingHeating

Variable ow: Pressure Independent Control (PICV) with digital actuator

FAN COIL UNITS (FCU)

I/O

PICV

Mixing loop

AHU cooling

AHU applications

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

1. Pressure Independent Control Valve

(PICV)

2. Building Management System (BMS)

3. Digital or Analogue Input/Output

(I/O)

Temperature control of the terminal unit is ensured with pressure independent valves. This will ensure the right ow at all system loads, regardless of pressure uctuations. The result will be stable and precise room temperature control to ensure a high ΔT and prevent actuators from hunting. The additional features of digital, connected actuators will enable better system monitoring and reduce maintenance cost.

Applicable for all terminal units, included AHU (see page 34, 36)

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

I/O

PICV

Danfoss products:

PICV: AB-QM 4.0 + NovoCon® S.

Explanation

CHILLED PANELS

BMS

Return of investment

• Reduction of components by eliminating the need for balancing valves

• Lower installation cost due to simplied installation

• Signicant energy savings* due to optimal working conditions for all components

• The higher cost for the SMART actuator can be oset by hardware savings like a reduced number of additional IOs

• High occupant satisfaction because of perfect balance and control extended with predictive maintenance and pro-active alarm functions

Design

• Easy selection of valves based only on the ow requirement

• No Kv or authority calculation* is needed, ow presetting calculation based on ow demand

• Proportional pump control is applicable. The pump(s) can be optimized easily *

• Suitable for BMS applications to monitor the system and reduce energy usage

• Wide range of possible connected I/O devices ensures large number of BMS variants

Operation/Maintenance

• The full commissioning procedure can be run through BMS ensuring less complexity and high exibility

• Low operational and upkeep cost because the system health can be monitored and maintained through BMS.

• High comfort (building classication) because of precise ow control at all loads

• High eciency in chillers, boilers and pumping because of the optimized ∆T in the system

• Flexible and expandable control system through BMS connectivity

Control

• No overows at partial system loads

• Perfect control because of full authority *

• Proportional control minimizes the ow circulation and optimizes the pump head

• Pressure independent solution, so pressure changes do not aect control circuits

• No low ∆T syndrome *

*see page 54-55

CoolingHeating

Variable ow: Flow limitation (with ow

Hydronic applications

Commercial

Not Recommended

limiter) on terminal unit with ON/OFF or modular actuator

FAN COIL UNITS (FCU)

CV-1

ON/OFF

CV-2 0-10V

Danfoss products:

CHILLED PANELS

BMS

CV-2: VZ2 + AME130 FL: AB-QMCV-1: RA-HC + TWA-A

1.1.1.4

1. 2-way Control Valve (CV)

2. Flow Limiter (FL)

3. Building Management System (BMS) or Room temperature Control (RC)

Temperature control of the terminal unit is done by conventional motorized control valves (CV) while the hydronic balance in the system is realized by automatic ow limiter (FL). For ON/OFF control this could be an acceptable solution, provided that the pump head is not too high. For modulating control this is not acceptable. The FL will counteract the actions of the CV and fully distort the control characteristic. Therefore, modulation with this solutions is impossible.

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

AHU applications

AHU heating

Explanation

Return of investment

• Relatively high product cost because of 2 valves for all terminal units (one CV + FL)

• Higher installation costs although no manual partner valves* are needed

• Variable speed pump is recommended (proportional pump control is possible)

Design

• Traditional calculation is needed but only the kvs of the control valve. It is not necessary to calculate the authority* since the FL will take away the authority of the CV

• For ON/OFF control it is an acceptable solution (simple design: big kvs of zone valve, ow limiter selected based on ow demand)

• High pump head is needed because of the two valves (additional Δp on ow limiter)

Operation/Maintenance

• Closing force of actuator should be able to close the valve against the pump head at minimum ow

• Most ow limiters have pre-determined ow, no adjustment is possible.

• For ushing cartridges need to be removed from the system and placed back afterwards (emptying and lling the system twice)

• Cartridges have small openings and clog easily

• If modulation is attempted the lifetime of the CV is very short due to hunting at partial system loads

• High energy consumption with modulation control due to higher pump head and overow on terminal units in partial load

Control

• Temperature uctuations due to ON/OFF control, even with modulating actuators*

• No overows*

• No pressure interdependency of the control circuits

• Overow during partial load when modulating because the FL will keep the maximum ow if possible

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

3-point or proportional control

acceptable

Chillers applications Boilers applications Hot water

excellent

ON/OFF control

*see page 54-55

Commercial

Hydronic applications

Acceptable

1.1.1.5

CoolingHeating

Variable ow: Dierential pressure control with ON/OFF or modulation

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

1. Zone Control Valve

(with presetting) (CV)

2. Zone Control Valve

(no presetting) (CV)

3. Manual Balancing Valve (MBV)

4. Δp Controller (DPCV)

5. Partner Valve*

6. Building Management System (BMS)

or Room temperature Control (RC)

1 2

6 6

Temperature control at the terminal unit is done by conventional motorized control valve (CV). Hydronic balance is achieved by dierential pressure controllers (DPCV) on the branches and manual balancing valves (MBV) at the terminal unit. If the CV has a pre-setting option the MBV is redundant.

CV-1

ON/OFF

CV-2 0-10V

Danfoss products:

FAN COIL UNITS (FCU)

DPCV

CHILLED PANELS

MBV

DPCV

BMS

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

It guarantees that, regardless of pressure oscillations in the distribution network, we have the right pressure and ow in the pressure-controlled segment.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

3-point or proportional control

acceptable

excellent

ON/OFF control

CV-2: VZ2 + AME130 DPCV: ASV-PV+ASV-BD MBV: MSV-BD CV-1: RA-HC +TWA-A

Explanation

Return of investment

• Requires Δp controllers and partner valves*.

• MBVs or pre-settable CV is needed for each terminal unit

• Cooling systems might require big and expensive (anged) Δp controllers

• Good energy eciency because there are only limited overows* in partial load

Design

• Simplied design because the branches are pressure independent

• Kv calculation needed for Δp controller and control valve. An authority* calculation is also needed for modulating control

• Pre-setting calculation for terminal units is necessary for proper water distribution within the branch

• The setting for the Δp controller needs to be calculated

• A variable speed pump is recommended

Operation/Maintenance

• More components to install included impulse tube connection between Δp - and partner valve*

• Simplied commissioning* procedure because of pressure independent branches

• Balancing on the terminal units is still required although simplied by Δp controlled branch

• Phased commissioning is possible (branch by branch)

Control

• Generally acceptable to good controllability

• Pressure uctuations that impact the controllability can occur with long branchesor and/or big Δp on terminal units

• Depending on the size of the branch overows can still result in room temperature uctuations.

• If we use ow limitation on partner valve* connected to Δp controller (not on terminal units), higher overow and room temperature oscillation* are expected

*see page 54-55

CoolingHeating

Variable ow: Shell and Core installation for

Hydronic applications

Commercial

Recommended

Oces and Shopping malls*

PICV-3

VACANT

Danfoss products:

PICV-1

PICV-3

PICV-2

PICV-3

VACANT

FAN COIL UNITS (FCU)

CHILLED PANELS

PICV-1

BMS

1.1.1.6

1. Combined Automatic Balancing Valve as Δp Controller (PICV 1)

2. Combined Automatic Balancing Valve as Flow Controller (PICV 2)

This application is useful specically for situations where the system is built in two phases by dierent contractors. The rst phase is usually the central infrastructure, like boilers, chillers and transport piping, while the second part includes the terminal units and room controls.

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

PICV-2 & PICV3: AB-PM + TWA-QPICV-1: AB-PM+AME435QM

Explanation

Return of investment

• Only one valve needed

• One actuator for zone or ow control

• Variable speed pump is recommended (proportional pump control is possible)

Design

• No kvs and authority* calculation needed.

• Presetting calculation needed only based on ow and Δp demand of loop

• For loop design (later stage of installation) the set parameters are available

Operation/Maintenance

• Reliable solution for shop or oor connection

• Flow setting can be done based on measurements on the test plugs of the valve

• Central distribution is always correctly balanced and independent of any mistakes made in sizing on the occupant ‚s side

• Changes in secondary section of the system do not inuence other shops or oors

• Easy trouble shooting, energy allocation, management, etc. with NovoCon

Control

• Stable pressure dierence for shops or oors

• If only ow limitation is used small overows can happen within the loop during partial load

• Actuator on valve (if applied) ensures either zone control (Δp control application) or ow control (ow control application)

This commonly occurs in shopping malls, where the shops use their own contractor to do the shop’s installation, or Shell & Core oces where the renter of an oce oor ts out his own space, including the HVAC.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

acceptable

excellent

AHU heating

Chillers applications Boilers applications Hot water

AHU applications

**Two dierent approaches can be chosen:

1. Flow and ΔP limitation. Here the valve limits both the ΔP and the ow.

2. Flow limitation only. This will require additional zone controls and balancing for the terminal units

*see page 54-55

poor

Δp control application

acceptable

excellent

Flow control application

Commercial

FAN COIL UNITS (FCU)

Hydronic applications

Not Recomended

1.1.1.7

CoolingHeating

Variable ow: Manual balancing

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

1. 2-way Control Valve (CV)

2. Manual Balancing Valve (MBV)

3. Partner Valve* (MBV)

4. Building Management System (BMS)

or Room temperature Control (RC)

The terminal units are controlled by conventional motorized control valves and the hydronic balance is achieved by manual balancing valve. Due to the static nature the MBV only ensures hydronic balance in full system load. During partial load under- and overows can be expected in the terminal units, causing excessive energy consumption as well as cold and hot spots in the system.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

CV-1

MBV-1

Danfoss products:

Explanation

MBV-1

CHILLED PANELS

CV-2 MBV-1

MBV-2

BMS

CV-2: VZ2 + AME130 MBV-1: MSV-BD MBV-2: MSV-F2 CV-1: RA-HC +TWA-A

Return of investment

• Many components are needed: 2 valves per terminal unit and additional branch valves for commissioning*

• Increased installation cost due to many valves

• Complex commissioning procedure is required increasing risk of a delayed.

• Variable speed pump is recommended with constant Δp function

Design

• Precise sizing is required (Kv-value, authority*)

• Authority* calculations are crucial for acceptable modulation

• Constant Δp pump control is recommended because of the proper location for the pressure

• It is impossible to predict system behaviour in partial load

Operation/Maintenance

• Complicated commissioning procedure that can only be executed by qualied sta

• Commissioning process can only be started at the end of the project with full load on the system and sucient access to all balancing valves

• High complaint costs because of balancing issues, noise and inaccurate control during partial load

• Rebalancing needed regularly and in case of changes in the system

• High pumping costs* because of overows during partial load

Control

• Interdependence of circuits creates pressure uctuations, which inuence control stability and accuracy

• The generated overow reduces the system eciency (high pumping cost*, low ΔT syndrome* in cooling system, room temperature oscillation*)

• Failure to create sucient pressure drop on the valve will result in low authority* which will make modulating control impossible

*see page 54-55

CoolingHeating

FAN COIL UNITS (FCU)

Variable ow: Manual balancing

Hydronic applications

Commercial

Not Recommended

with reverse return

CV-1

CV-2

Danfoss products:

Explanation

MBV-1

CV-2: VZ2 + AME130 MBV-2: MSV-F2 MBV-1: MSV-BD CV-1: RA-HC +TWA-A

MBV-1

CHILLED PANELS

MBV-1

MBV-2

BMS

1.1.1.8

4 4

1. 2-way Control Valve (CV)

2. Manual Balancing Valve (MBV)

3. Partner Valve* (MBV)

4. Building Management System (BMS) or Room temperature Control (RC)

In a reverse return system (Tichelmann), the piping is designed in such way that the rst terminal unit on the supply is the last one on the return. The theory is that all terminal units have the same available Δp and therefore are balanced. This system can only be used if the terminal units are the same size and have constant* ow. For other systems this application is unsuitable.

Performance

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

AHU applications

AHU heating

Return of investment

• Due to extra pipe runs the investment is much higher

• More space needed in technical shaft for additional third pipe

• Bigger pump needed because of added resistance of additional piping

• High complaint costs because of the balancing issues, noise and inaccurate control during partial loads

Design

• Complicated piping design

• Precise control valve sizing is required (Kv-values, authority*)

• Authority* calculations are crucial for acceptable modulation

• Constant Δp pump control is recommended, it is impossible to use a Δp sensor

• The system is only balanced during full load conditions

• It is impossible to predict system behaviour in partial load

Operation/Maintenance

• Complicated commissioning* procedure that can only be executed by qualied sta

• Commissioning process can only be started at the end of the project with full load on the system and sucient access to all balancing valves

• Δp sensor does not solve over pumping issues

• Rebalancing needed in case of changes in the system

• Extra high pumping costs* because of third pipeline and overows during partial load

Control

• Interdependence of circuits creates pressure uctuations which inuence control stability and accuracy

• The generated overow reduces the system eciency (high pumping cost*, low ΔT syndrome* in cooling system, room temperature oscillation*)

• Failure in creating sucient pressure drop on the valve will result in low authority which* will make modulating control impossible

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

Chillers applications Boilers applications Hot water

excellent

*see page 54-55

Commercial

Hydronic applications

Recommended

1.1.1.9

CoolingHeating

Variable ow: Four-pipe Changeover (CO6) for radiant heating/cooling panels, chilled beams, etc. with PICV control valve

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

1. 6-way Valve

2. Pressure Independent

Control Valve (PICV)

3. Building Management System (BMS)

This application is useful if you have one heat exchanger that needs to do both heating and cooling. This t well with radiant panel solutions. The application uses a 6-way valve for switching over between heating and cooling and a PICV is used to balance and control the ow.

Danfoss products:

6-way value

FAN COIL UNITS (FCU)

PICV

6-way value

PICV

BMS

6-way valve + PICV: NovoCon ChangeOver6 +AB-QM

CHILLED PANELS

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

Explanation

Return of investment

• Only two valves are needed instead of four. One for changeover* and one for heating/ cooling control

• Very energy ecient thanks to high ∆T and no overows*

• Low commissioning* cost because only the ow needs to be set either on PICV or on BMS when using a digital actuator

• BMS costs are reduced because only one datapoint is needed

Design

• Easy selection of PICV, only the ow is required for sizing

• No Kv or authority* calculations needed

• The Δp on CO6 valve does need to be checked

• Perfect balance and control under all loads ensuring precise room temperature control

Operation/Maintenance

• Simplied construction because of reduction of components and pre-built sets

• One valve controls both cooling and heating

• Low complaint costs because of perfect balance and perfect control at all loads

• No cross ow between heating and cooling

• Low operational and upkeep cost. Flushing, purging, energy allocation and management can all be done through BMS.

Control

• Perfect control because of full authority*

• Individual settings for cooling and heating (ow), so perfect control in both situations

• Precise room temperature control

• Digital actuator ensures further saving with energy measurement and management function

*see page 54-55

CoolingHeating

Variable ow: Two-pipe heating/cooling

Hydronic applications

Commercial

Acceptable

system with central changeover*

FAN COIL UNITS (FCU)

PICV-1

CHILLED PANELS

PICV-2

HEATING

SUPPLY/RETURN

Danfoss products:

PICV-1: AB-QM 4.0 + TWA-Q PICV-2: AB-QM 4.0 + AMI-140

SUPPLY

RETURN

COOLING

1.1.1.10

1. Central Changeover Valve

2. Pressure Independent Control Valve (PICV)

3. Room thermostat (RC)

In this application a central change guarantees that the rooms can be cooled and heated. It is strongly recommended to use a PICV to control the temperature because of the dierent ow requirements for the heating and cooling.

3 3

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

AHU applications

AHU heating

Explanation

Return of investment

• Heavily reduced construction cost due to elimination of a secend set of pipes

• Extra costs if automatic changeover* is required

• Proportional pump control is recommended

Design

• Simple PICV selection according to cooling ow, which is usually the highest

• The change-over valve needs to be selected according to the biggest ow rate (cooling) and a big Kvs is recommend to reduce the pumping cost*

• Dierent ow rates for heating and cooling need to be ensured, either by limiting the actuator stroke or by the ability to remotely set the maximum ow, (digital actuator)

• In most cases a dierent pump head is needed for heating and cooling

Operation/Maintenance

• Simple system setup with few valves, so low maintenance cost

• The seasonal changeover* needs to be managed

• No overow* (if ow can be set for dierent heating/cooling mode)

Control

• Simultaneous heating and cooling in dierent rooms is not possible

• Perfect hydronic balancing and control with PICV

• ON/OFF control results in overows when the ow limitation is not solved for lower ow demand (heating)

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

Chillers applications Boilers applications Hot water

excellent

*see page 54-55

Commercial

Hydronic applications

Not Recommended

1.1.2.1

CoolingHeating

Constant ow: 3-way valve with manual balancing (in fan-coil, chilled beam etc. application)

FAN COIL UNITS (FCU)

MBV-1

CV-1

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

1. 3-way Control Valve (CV)

2. Manual Balancing Valve (MBV)

3. Partner Valve* (MBV)

4. Building Management System (BMS)

or Room temperature Control (RC)

In this application temperature control on the terminal unit is done by using 3-way valves. Manual balancing valves are used to create hydronic balance in the system. This application should be avoided due to its high energy ineciency.

MBV-1

Danfoss products:

CV-2

MBV-1

CHILLED PANELS

MBV-2

BMS

CV-2: VZ3 +AME130 MBV-2: MSV-F2CV-1: VZL3 + TWA-ZL

MBV-1: MSV-BD

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

Explanation

Return of investment

• Many components are needed: a 3-way valve and a balancing valve per terminal unit and additional branch valves for commissioning*

• Extremely high operational cost, very energy inecient

• The ow is close to constant, no variable speed drive applied

• In partial loads very low ΔT in the system, so boilers and chillers run at very low eciency

Design

• Kv calculation is required, as well as an authority calculation* for the 3-way valve in case of modulation

• A by-pass needs to be sized or a balancing valve should be tted. Otherwise big overows in partial loads can occur causing terminal unit starvation and energy ineciencies.

• For the Pump head calculation partial load needs to be considered if overows on the by-pass are expected

Operation/Maintenance

• Commissioning of the system is required

• The hydronic balance at full- and partial load is acceptable

• Huge pump energy consumption due to constant operation

• High energy consumption (low ΔT)

Control

• The water distribution and the available pressure on the terminal units are more or less constant under all loads

• The room temperature control is satisfactory

• An oversized control valve will result in low rangeability and oscillation* with modulation

ON/OFF control

Modulation control

*see page 54-55

CoolingHeating

FAN COIL UNITS (FCU)

Constant ow: 3-way valve with ow limiter

Hydronic applications

Commercial

Not Recommended

on terminal units (fan-coil, chilled beam etc. application)

Danfoss products:

CV-1

CHILLED PANELS

CV-2

BMS

1.1.2.2

1. 3-way Control Valve (CV)

2. Flow Limiter (FL)

3. Building Management System (BMS) or Room temperature Control (RC)

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

CV-2: VZ3 +AMV-130CV-1: VZL3 + TWA-ZL

Explanation

FL: AB-QM

Return of investment

• Many components are needed: a 3-way valve and an automatic ow limiter per terminal unit

• Fairly simple valve setup, no need for a balancing valve in by-pass or other valves for commissioning*

• Extremely high operational cost, very energy inecient

• The ow close to constant, no variable speed drive applied

• In partial loads very low ΔT in the system, so boilers and chillers run at very low eciency

Design

• Kv calculation is required, as well as an authority* calculation for the 3-way valve in case of modulation.

• Sizing and presetting of the ow limiters is based on the nominal ow of terminal unit

• For the Pump head calculation partial load needs to be considered if overows on the by-pass are expected.

Operation/Maintenance

• Commissioning of the system is required

• The hydronic balance at full- and partial load is acceptable

• Huge pump energy consumption due to constant operation

• High energy consumption (low ΔT)

Control

• The water distribution and the available pressure on the terminal units are more or less constant under all loads

• The room temperature control is satisfactory

• An oversized control valve will result in low rangeability and oscillation* with modulation

In this application temperature control on the terminal unit is done by using 3-way valves. Automatic ow limiters are used to create hydronic balance in the system. This application should be avoided due to its high energy ineciency.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

AHU heating

Chillers applications Boilers applications Hot water

AHU applications

*see page 54-55

ON/OFF control

Modulation control

Commercial

Hydronic applications

Residential

Hydronic applications

Recommended

1.2.1.1

CoolingHeating

Two-pipe radiator heating system – risers with, thermostatic radiator valves (with presetting)

TRV-2

TRV-1

Mixing loop

AHU cooling

AHU applications

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

1. Termostatic Radiator Valve (TRV)

2. Return Locking Valve (RLV)

3. Δp controller (DPCV)

4. Partner valve*

In this application we ensure variable ow* on risers with thermostatic radiator valves. In case of presetting available on TRV, ΔP controller used without ow limitation on the riser.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

2 2

acceptable

excellent

DPCV

Danfoss products:

TRV-1: RA build in + RA TRV-2: RA-N + RA

Explanation

DPCV

DPCV: ASV-PV+ASV-BD

Return of investment

• Δp controller is more expensive compared to manual balancing

• Commissioning is not needed only Δp setting on Δp controller and ow pre-setting on TRVs

• Variable speed pump is recommended

Design

• Simple calculation method, Δp controlled risers can be calculated as independent loops (you can split the system by risers)

• The presetting calculation of radiators is needed,

• Kv calculation needed for Δp controller and control valve. Authority calculation also needed for proper TRV operation

• The Δp demand of loop should be calculated and set according nominal ow and system resistance

Operation/Maintenance

• Hydraulic regulation is in the bottom of risers and radiator presetting

• No hydronic interference among the risers

• Balancing at full and partial load – good – with TRV presetting

• Good eciency: increased ΔT on riser and variable speed pump ensures energy saving

Control

• The eciency of system good with individual presetting on radiators

• Low pumping costs – the ow rate of risers are limited.

• Maximum ΔT on risers

poor

acceptable

excellent

*see page 54-55

CoolingHeating

TRV

Two pipe radiator heating system – risers

Hydronic applications

Commercial

Acceptable

with, thermostatic radiator valves (without presetting)

RLV-2

DPCV

1.2.1.2

Hydronic applications

Residential

2 2

Mixing loop

1. Termostatic Radiator Valve (TRV)

2. Return Locking Valve (RLV)

3. Δp controller (DPCV)

4. Partner valve*

AHU applications

AHU cooling

Danfoss products:

DPCV: ASV-PV+ASV-BD

Explanation

Return of investment

• Δp controller plus ow limitation is more expensive then manual balancing

• Commissioning* is needed for ow limitation on the bottom of riser plus dp setting on Δp controller

• Variable speed pump is recommended

Design

• Simple calculation method, Δp controlled risers can be calculated as independent loops (you can split the system by risers)

• The presetting calculation of partner valve* for ow limitation is required

• Kv calculation needed for Δp controller and control valve. Authority *checking is also essential to know the control performance of TRV

• The Δp demand of loop should be calculated and set according nominal ow and system resistance

Operation/Maintenance

• Hydronic regulation is at the bottom of risers only

• No hydronic interference among the risers

• Balancing at full and partial load is acceptable

• Acceptable eciency and variable speed pump ensures energy saving*

Control

• The ow limitation at the bottom of riser causes extra pressure drop within the Δp controlled loop therefore higher overow appears during partial load (compared to presetting on TRV )

• Higher pumping costs* – however the ow rate of risers is limited slight oveow occure within the riser during partial load condition

• Acceptable ΔT on risers (lower comparing to presetting on TRV)

In this application we ensure variable* ow on risers with thermostatic radiator valves. No possibility of presetting on TRV, ΔP controller used with ow limitation on the riser with partner valve*.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

AHU heating

Chillers applications Boilers applications Hot water

AHU applications

*see page 54-55

Commercial

Hydronic applications

Recommended

1.2.1.3

CoolingHeating

Pressure Independent Control for radiator heating system

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

3 4

1. Radiator Dynamic Valve (RDV)

2. Termostatic Radiator Valve (TRV)

3. Return Locking Valve (RLV)

4. Return Locking

Dynamic Valve (RLDV)

In this application Pressure Independent Control Valves used in smaller radiator heating system combined with thermostatic senor (self-acting proportional room temperature control), give us a guarantee that regardless of the pressure oscillation inside the system, we will secure the right ow, allowing the right amount of heat to be delivered to the room. (Traditional radiator or „H” piece connection available).

Danfoss products:

RDV

TRV-1: RA build in + RA

TRV

RLDV

RLDV: RLV-KDVRDV: RA-DV + RA

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

Explanation

Return of investment

• A minimal number of components is needed which means less installation costs

• Low complaint costs because of perfect balance and perfect control at all loads

• Highly energy eciency because of precise ow limitation at all loads

• High eciency of boilers and pumping because of high ∆T in the system

Design

• Easy selection of valves based only on ow requirement

• No Kv or authority* calculation is needed, presetting calculation is based on ow demand

• Perfect balance and control at all loads

• Proportional pump control is recommended, pump speed can be optimized easily

• This solution applicable up to max. 135 l/h ow rate on terminal unit and max 60 kPa pressure dierence across the valve

• Min available Δp on the valve 10 kPa

Operation/Maintenance

• Simplied construction because of reduction of components

• Set and forget, no complicated balancing procedures are needed

• Changes of ow setting do not inuence the other users

• Flow verication is possible on the valve with special tool

Control

• Perfect control because of full authority*

• No overows*

• Fix 2K proportional Xp band

• Fully pressure independent so no interference from pressure uctuations and therefore stable room temperatures*

*see page 54-55

CoolingHeating

Subordinated risers (staircase, bathroom,

Hydronic applications

Commercial

Recommended

etc.) in two- or one-pipe radiator heating system without thermostatic valve

TRV

RLV

PICV +QT

Danfoss products:

TRV: RA-N+RA PICV+QT: AB-QT

1.2.1.4

1. Radiator Valve (without sensor) (RV)

2. Pressure Independent Control Valve (PICV)

3. Temperature Sensor (QT)

In this application we have theoretical constant ow* on subordinated risers and no thermostatic sensor on radiator valve (like staircase, bathroom etc.) For better eciency we ensure variable ow* in case of partial load condition when the return temperature is increasing, with return ow temperature limitation.

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

AHU applications

AHU heating

Explanation

Return of investment

• QT (temperature limiter sensor) is an extra cost (ow limiter is recommended in any case)

• Commissioning of the system is not required only setting of ow on PICV and temperature on QT

• VSD pump is recommended

Design

• Simple calculation is required for riser ow, based on heat demand and ΔT, the size of radiator, convector has to be designed accordingly

• The ow is controlled by return temperature signal

• The presetting calculation of radiator is crucial due to no room temperature controller, the heat emission will depend on ow rate and size of radiator. The presetting calculation is based on ow rate among radiators and pressure drop of pipeline

• Simplied hydraulic calculation (you can split the system by risers)

Operation/Maintenance

• No overheating on riser during partial load condition (strongly recommended for renovation)

• Good balancing at full and partial load - additional energy saving*

• Higher eciency, limited return temperature and variable speed pump ensures energy saving*

Control

• Inner rooms (typically bathrooms) have constant heat demand, to keep constant heat output, with increasing ow temperature, QT reduces the ow rate.

• Less overheating of risers – energy saving*

• ΔT increasement ensures lower heat loss and better heat production eciency

• LOW pumping costs* – the ow rate of subordinated risers are limited and reduced even more with temperature limitation by QT

• Limited eciency of QT control when ow temperature drops. Electronic controller (CCR3+) increases eciency at higher outdoor temperature.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

Chillers applications Boilers applications Hot water

excellent

*see page 54-55

Commercial

Hydronic applications

Residential

Hydronic applications

Mixing loop

Recommended

1.2.1.5

1. Δp controller (DPCV)

2. Partner valve*

3. Manifold with presettable valves

CoolingHeating

Δp control for manifold with individual zone/loop control

DPCV

AHU cooling

AHU applications

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

In this application we ensure variable ow* in the distribution pipeline and constant dierential pressure on each manifold independently from temporal load and pressure uctuation in the system. Applicable for both radiator and oor heating systems.

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

Danfoss products:

Manifold: FHF + TWA-A

Explanation

DPCV: ASV-PV + ASV-BD

Return of investment

• Beside manifold we need DPCV with partner valve*. Heat meter is often used for individual at connections

• Thermal actuator for zone control (oor heating) or thermostatic sensor (radiator)

• Commissioning is not needed, Δp setting and ow setting on manifold loops only

• With additional investment, the users’ comfort can be increased with individual, time based wired or wireless room temperature control

• Variable speed pump is recommended

Design

• Simple DPCV sizing according kvs calculation and total ow demand of manifold

• Presetting calculation is needed for built in zone valves only

• The presetting of loops, limiting the ow to be ensured no under/overow on connections

Operation/Maintenance

• Reliable, pressure independent solution for individual at/manifold connection

• Partner valve* can have dierent functions like, impulse tube connection, shut o, etc.

• Flow setting can be done accurately via Δp setting on DPCV with heat meter most often used

• NO noise risk thanks for Δp controlled manifolds

• High eciency, especially with individual programmable room control

Control

• Stable pressure dierence for manifolds

• Flow limitation is solved, no overow* or underow per connections

• Thermal actuators (oor heating) ensure manifold or individual time based room temperature zone control (ON/OFF) with suitable room controller

• Thermostatic sensor (radiator) ensures proportional room control with proper Xp band

*see page 54-55

CoolingHeating

Δp control and ow limitation for manifold

Hydronic applications

Commercial

Recommended

with central zone control

Danfoss products:

Manifold: FHF

DPCV

ABV: AB-PM +TWA-Q (optional)

1.2.1.6

1. Δp controller (DPCV)

2. Manifold with presettable valves

In this application we ensure variable ow* in the distribution pipeline and maximum pressure dierence on each manifold independently from temporal load and pressure uctuation in the system. Furthermore, we limit the ow for manifold and able to ensure zone control with adding thermal actuator on DPCV. Applicable for both radiator and oor heating systems.

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

AHU applications

AHU heating

Explanation

Return of investment

• DPCV and impulse tube connection needed only. Heat meter often used for individual at connection

• Thermal actuator for zone control as option (installed on DPCV)

• Individual zone control (oor heating) or thermostatic sensor (radiator) also possible

• Installation time can be reduced with usage of set solution

• Commissioning is not needed, ow setting on DPCV only and presetting of each loop

• Variable speed pump is recommended

Design

• Simple, no kvs and authority* calculation, valve selection based on ow rate and Δp demand of loop

• Presetting calculation is needed for built-in zone valves (if there are)

• The presetting of ow limitation ensures no under/overow on manifold

• Pump head calculation is very simple, min available pressure dierence for DPCV (included the loop Δp) is given

Operation/Maintenance

• Reliable, pressure independent solution for individual at connection

• Partner valve* – if applied - can have dierent functions like, impulse tube connection, shut o, etc.

• No noise risk thanks to Δp controlled manifold

• High eciency, especially with individual programmable room control

Control

• Maximized pressure dierence for manifold

• Flow limitation is solved, no overow* or underow per connections

• ...but slight overow within the loop during partial load

• Thermal actuator ensures zone control (ON/OFF) with suitable room controller

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

Chillers applications Boilers applications Hot water

excellent

*see page 54-55

Commercial

Hydronic applications

Recommended

1.2.2.1

CoolingHeating

One-pipe radiator heating system renovation with automatic ow limitation and possible self-acting return temperature limitation

Residential

Hydronic applications

Mixing loop

AHU cooling

AHU applications

1. Radiator Valve (TRV )

2. Pressure Independent Control Valve

(PICV)

3. Optional - Temperature Sensor (QT)

This application is suitable for renovating of vertical one-pipe radiator heating system. We recommend high capacity thermostatic radiator valve and ow limiter installation on riser. For better eciency we optionally recommend to use return temperature control with QT (Thermostatic Sensor)

Danfoss products:

TRV

PICV

PICV: AB-QM

PICV+QT

PICV+QT: AB-QTTRV: RA-G + RA

AHU heating

AHU applications

Chillers applicationsBoilers applicationsHot water

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

With QT Without QT

acceptable

excellent

Explanation

Return of investment

• Investment cost are higher (thermostatic radiator valve + ow limiter + QT on risers) compared to manual balancing

• Simple QT installation with low extra cost

• No commissioning* demand only ow setting

• Variable speed pump is recommended (without QT the pump control is not needed)

Design

• „α” (radiator share) calculation with iteration

• Big capacity TRV is needed to increase the „α”

• Radiator size depends on ow temperature changes

• Gravitation eect should be taken into account

• Simple hydronic calculation regarding riser controller, selection based on ow rate but we need to ensure the minimum available pressure on it

• QT setting depends on system conditions

Operation/Maintenance

• System less sensitive for gravitation eect due to ow limitation

• „α” (radiator share) sensitive for installation punctuality

• Real constant ow* without QT, variable ow* with QT

• QT contributes to energy saving* on pumping

• QT ensures more accurate heat cost allocation

Control

• Accurate and simple water distribution among risers

• Improved room temperature control

• The radiator heat emission depends on varying ow temperature

• Heat gain from pipe in the rooms aects the room temperature

• QT eect is limited in case of higher outdoor temperature

*see page 54-55

CoolingHeating

One-pipe radiator heating system renovation

Hydronic applications

Commercial

Recommended

with electronic ow limitation and return temperature control

TRV

PICV

CCR3+

1.2.2.2

1. Radiator Valve (TRV )

2. Pressure Independent Control Valve (PICV)

3. Elecrtonic Controller (CCR3+)

4. Temperature sensor (TS)

CCR3+

Hydronic applications

Residential

Mixing loop

AHU applications

AHU cooling

Danfoss products:

TRV: RA-G + RA

Explanation

PICV: AB-QM+TWA-Q CCR3+

Return of investment

• High investment cost (thermostatic radiator valve + ow limiter with thermal actuator, sensor on risers + CCR3+)

• Electronic wiring is needed, programing CCR3+

• No commissioning* demand only ow setting

• Variable speed pump is recommended

Design

• „α” (radiator share) calculation with iteration

• Big capacity TRV is needed to increase the „α”

• Radiator size depends on ow temperature changes

• Gravitation eect should be taken into account

• Simple hydronic calculation regarding riser controller, selection based on ow rate but we need to ensure the minimum available pressure on it

• Dening of needed return characteristic

Operation/Maintenance

• The system less sensitive for gravitation eect due to ow limitation

• „α” (radiator share) sensitive for installation punctuality

• Programming CCR3+, data logging, remote maintenance and access

• Higher eciency due to improved ΔT, and reduced pipe heat loss

Control

• Accurate and simple water distribution among risers

• Improved room temperature control

• The radiator heat emission depends on varying ow temperature

• Heat gain from pipe in the rooms aects the room temperature

• CCR3+ Weather compensation on return temperature on all individual risers

This application is suitable for renovating of vertical one-pipe radiator heating system. We recommend high capacity thermostatic radiator valve and ow limiter installation on riser. For best eciency we recommend to use CCR3+ (Electronic Controller)

Performance

Return of investment

poor

Design

poor

Operation/Maintenance

poor

Control

poor

acceptable

excellent

AHU heating

Chillers applications Boilers applications Hot water

AHU applications

*see page 54-55

+ 61 hidden pages

Danfoss How to design balancing and control solutions for energy efficient hydronic applications in residential and commercial buildings Application guide

Specifications and Main Features

Frequently Asked Questions

User Manual