Benefits of Floor Heating ControlIndividual Room Temperature Control In Hydronic FloorHeating Applications – Simulation Studies, August 2003Danfoss Floor Heating Hydronics

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Benefits of Floor Heating Control

Personal Thermal Comfort

Room temperature is a main factor for personal thermal comfort The desired room temperature depends on activity, clothing, and personal ”taste” Desired temperatures varies for each room in the house

Kitchen ~ 20 C°

Bedroom ~ 17 C°

Bathroom ~ 23 C°

Living room ~ 20 C°

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Benefits of Floor Heating Control

How Do We Achieve Optimal Personal Thermal Comfort ?

In order to achieve the desired temperature in each room it must be possible for the user to define/set the temperature in each room

It must be possible to differentiate temperatures between the rooms, - e.g. typically the user wishes the bathroom to be warmer than the bedroom

The heating system should at all times supply the correct amount of energy needed to each room so that large fluctuations resulting in the room being too warm or too cold is avoided

Optimal comfort is achieved when the user has exactly the temperature desired in each room of the house

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Benefits of Floor Heating Control

Individual Room Temperature Control

Desired temperature in bathroom

Desired temperature in living room

Desired temperature in bedroom

Temperature without individual room control

Temperature with individual room control

Hour

°C temperature

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Benefits of Floor Heating Control

Individual Room Temperature Control – Conclusion

In order to fulfill the desire for optimal personal thermal comfort it is necessary to utilize Individual Room Temperature Controls of your heating system

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Benefits of Floor Heating Control

Individual Room Temperature Controls

Precise regulation of the temperature corresponding to the specific set-point chosen for each room by the user

Individual Room Temperature Controls adjust heat flow depending on user pattern, free heat through windows, appliances, etc. Optimal personal thermal comfort

Individual Room Temperature Controls adapt heat output to heat loss in each room Minimized costs with regard to energy consumption/saving

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Benefits of Floor Heating Control

The Simulation Studies

Danfoss has carried out simulation studies in order to clarify the importance of Individual Room Temperature Control of the heating system with regard to:

Personal thermal comfort

Energy consumption

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Benefits of Floor Heating Control

The Simulation System: IDA Indoor Climate and Energy 3.0

IDA Indoor Climate and Energy 3.0 is a general-purpose modeling and simulation tool for modular systems where components are described with equations

IDA Indoor Climate and Energy 3.0 is a new generation tool for simulation of thermal comfort, indoor air quality and energy consumption in buildings

More than 900 registered users, mostly HVAC designers but also educators and researchers

First version was released in May 1998. Version 3.0, released in November 2001, marks a major development step with several significant improvements

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Benefits of Floor Heating Control

The Simulation System: IDA Indoor Climate and Energy 3.0

IDA Indoor Climate and Energy 3.0 is developed by the company EQUA in close co-operation with a network of academic institutions, each contributing through expert usage and model development:

Royal Institute of Technology , Stockholm, Sweden Building Services Engineering, Sweden Helsinki University of Technology, Heating, Ventilating and Air-Conditioning, Finland Hochschüle für Technik+Architektur, HLK Engineering, Luzern, Switzerland University of Kassel, Department of Building Physics, Germany Norweigan University of Science and Technology, Dept. of Refrigeration and Airconditioning, Norway

For more information please refer to the EQUA homepage http://www.equa.se

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Benefits of Floor Heating Control

System Control Methods

Automatic control of flow temperature using an electronic weather compensator

With individual room temperature control Without individual room temperature control

Manual control of flow temperature by occupant operation of self-acting flow regulator

With individual room temperature control Without individual room temperature control

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Benefits of Floor Heating ControlAutomatic Control of Flow Temperature Using an Electronic Weather Compensator

No occupant interaction on the heating system during heating season Apartment with 6 rooms No reference room control Doors to bathroom and bedroom closed and the other doors open Flow control to each room is on/off with a dead-band of 0.25 °C Minimum operative temperatures registered in the rooms equals desired temperatures Flow temperature is adjusted to ensure desired indoor temperatures at a coldest day of -12°C Thermal comfort related to tube layout is not included in the study Only energy consumption in association with room heating is considered - efficiency of the energy producing and delivering system is not considered

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Benefits of Floor Heating ControlManual Control of Flow Temperature by Operation of Self-acting Flow Regulator

The occupant checks the flow temperature with regular intervals and change the set-point of the flow temperature regulator if the deviation between proposed value and present value of the flow temperature is more than 2°C No occupant interaction on the room thermostats during heating season Apartment with 6 rooms Doors to bathroom and bedroom closed and the other doors open Flow control to each room is on/off with a dead-band of 0.25 °C Minimum operative temperatures registered in the rooms equals desired temperature Flow temperature is adjusted to ensure desired in-door temperatures at a coldest day of -12 °C Thermal comfort related to tube layout is not included in the study Only energy consumption in association with room heating is considered - efficiency of the delivering and energy producing system is not considered

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Benefits of Floor Heating Control

Settings For Both Simulations

Heating season: 9 months (September to May)

Set-point temperatures (degrees Celsius) Living room 20°C Corridor 20°C Bedroom 17°C Bathroom 23°C Kitchen 20°C Childrens room 20°C

Measured results % of time during heating season, where operative temperature deviates with less than 1 celcius degree from set-point temperature

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Benefits of Floor Heating ControlAutomatic Control Of Flow Temperature Using An Electronic Weather Compensator

0 10 20 30 40 50 60 70 80 90 100

Childrens room

Kitchen

Bathroom

Bedroom

Corridor

Living room

Without individual room temperature control

With individual room temperature control

% of time during heating season, where operative temperature deviates with less than 1 celcius degree from set-point temperature

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Benefits of Floor Heating ControlManual Control of Flow Temperature by Operation of Self-acting Flow Regulator

0 10 20 30 40 50 60 70 80 90 100

Childrens room

Kitchen

Bathroom

Bedroom

Corridor

Living room

Without individual room temperature control

With individual room temperature control

% of time during heating season, where operative temperature deviates with less than 1 celcius degree from set-point temperature

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Benefits of Floor Heating Control

Conclusions: Personal Thermal Comfort

Significantly improved personal thermal comfort with individual room temperature controls

Individual Room Temperature Control is optimal in combination with both electronic weather compensator and occupant interaction for regulation of flow temperature

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Benefits of Floor Heating Control

Results on Energy Consumption

Flow temperature controlPre-settingof manifold

valves

Withoutroom

temperaturecontrols

Withroom

temperaturecontrols

Reductionin energyconsumpti

on

Automatic– using an electronic weather compensator

Yes 8372 kWh 7392 kWh 12%

Automatic– using an electronic weather compensator

No 9550 kWh 7390 kWh 23%

Manual– occupant operation of self-acting flow regulator

Yes 9009 kWh 7552 kWh 16%

Manual– occupant operation of self-acting flow regulator

No 10412 kWh 7681 kWh 26%

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Benefits of Floor Heating Control

Conclusions: Energy Consumption

Significant energy savings can be achieved with Individual Room Temperature Controls

15-25%

Significant energy savings can be achieved in combination with both electronic weather compensator and occupant interaction for regulation of flow temperature

The simulation results support independent research by e.g. M. Bauer, University of Stuttgart, who shows possible energy savings of approx. 20-40% for similar applications

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Benefits of Floor Heating ControlSimulation Data:Automatic Control Of Flow Temperature Using An Electronic Weather Compensator

Heating season: 9 months

(September to May)

Set-pointtemperat

ure(oC)

% of time during heating season, where operative temperature deviates with less than

1oC from set-point temperature

Without room control

With room control

Living room 20 70% 98%

Corridor 20 9% 100%

Bedroom 17 0% 67%

Bathroom 23 46% 91%

Kitchen 20 2% 99%

Childrens room 20 0% 97%

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Benefits of Floor Heating ControlSimulation Data:Manual Control of Flow Temperature by Operation of Self-acting Flow Regulator

Heating season: 9 months

(September to May)

Set-pointtemperat

ure (oC)

% of time during heating season, where operative temperature deviates with less than

1oC from set-point temperature

Without room control

With room control

Living room 20 30% 96%

Corridor 20 9% 97%

Bedroom 17 0% 56%

Bathroom 23 30% 98%

Kitchen 20 7% 92%

Childrens room 20 2% 88%