27 January 2015

Role of Building Automationrelated to Renewable Energy in nearly Zero Energy Buildingsby Markus Offermann

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Background

> Electricity consumption in European non-residential buildings has

increased by 74% over the past 20 years

> As of 31.12.2020 the recast of the EPBD requires all new buildings to be

“nearly Zero Energy Buildings”

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Questions

> Which types of buildings offer the best chances to benefit from automation?

> Which type of energy demand and/or which types of renewable energy are

most suited to control?

> What can be done to help policy towards regulations regarding building

automation to

● reduce the energy demand of future non-residential buildings

significantly?

● optimise the use of renewable energy?

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Non-residential building types

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31%

15%

38%

26%

69%

85%

62%

74%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Office School Supermarket Hotel

Energy consumption

non-residential buildings, Germany

electricity fuel

Typical shares of energy consumption at existing building types*

* in GermanyData source: Schlomann, Kleeberger et al, 2011: Energieverbrauch des Sektors Gewerbe, Handel, Dienstleistungen (GHD) in Deutschland für die

Jahre 2007 bis 2010. Fraunhofer ISI/IfE/GfK/IREES GmbH/BASE-ING. GmbH. 2011

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Nearly zero-energy buildings

> Energy Performance of Buildings Directive (EPBD):

"Building that has a very high energy performance… [ ]. The nearly zero or

very low amount of energy required should to a very significant extent be

covered by energy from renewable sources, including renewable energy

produced on-site or nearby.“

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Example

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[1] Boermans, Thomsen et al., Principles for nearly-zero energy buildings, Buildings Performance Institute Europe (BPIE), 2011

Nearly zero office building in different European climate zones

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Renewable energy on site

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1. Solar:

– PV

relevant potentials, especially in Southern regions

– Solar thermal collectors

less relevant for most non-residential buildings

(exception e.g. hotels)

2. Wind:

– Not relevant on site

3. Geothermal energy, biomass, energy from waste:

– If available, always available: no special need for control

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Storages

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Thermal storages: Short term (e.g. thermal building mass)

> Seasonal thermal & decentral electricity storages: economically not feasible

Figure 1 Thermal energy balance and load shifting potential (green arrows) of a nearly zero energy office building in Germany

during one week in January. Source: Ecofys

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Main functions of building automation

> Central, concerted control of all energy related components

> Monitoring and providing feedback

> Load shifting and storage management

> Ensuring thermal comfort

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Central, concerted control of all energy related

components

1. Saving potentials of 50% achievable

Reduction of energy demand heating, cooling and lighting

(e.g. by central control of external blinds)

BUT:

2. Total savings at nZEBs are low

Payback difficult

3. Control also demands energy

e.g. individual room controls critical

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Monitoring and providing feedback

1. To insure the energy consumption meets the calculated

(low) energy demand of the nearly zero energy building

Often there are gaps due to

● insufficient parameter settings and/or

● derivations from planning

2. To encourage the building users to save energy

Usually, the users have no feedback on their energy consumption.

The influence of user behaviour ist estimated to be at least

between 5 % and 30 %.

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Load shifting and storage management

1. Use thermal building masses

At well insulated and heat protected buildings

the thermal energy demand is flexible in time

– solar gains in winter or at night, cooling in summer

– flexible electricty tariffs can be used,

e.g. to control the heat supply by heatpumps

> Increased grid stability, increased potential of renewable energies

2. Increase the direct usable share of renewables on site (Pv)

Achievable direct total energy coverage

– in Southern Europe up to 50 %

– in Northern regions max. 20 %

> Heat demand coverage small

> Coverage rates can be increased further with batteries

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Ensuring thermal comfort

1. Sophisticated control is required

Especially at nearly zero energy buildings with

– a small thermal mass

– very slow reacting systems,

like floor heating or concrete cooling

> Allowing the implementation of heating and

(ground water) cooling systems with a high efficiency

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Pathways for building automation

with focus on nearly zero non-residential buildings

Central, concerted control of all energy related components

> Sophisticated central systems with producer-independent compatibility are

available (e.g. BACnet), but need to be further developed and supported to

be standard requirement for nearly zero energy buildings

> More transparency concerning the energy demand of (sophisticated) building

automation systems is required.

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Proposed actions

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Pathways for building automation

with focus on nearly zero non-residential buildings

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Monitoring and providing feedback

to ensure that the calculated (low) energy demand is met

> Further research to specify the potential gap between paper and reality

> By policy: Development of suitable regulations

> By industry: Development of suitable feedback systems

to the users to encourage them to save energy

> Further research to provide evidence of the potentials and costs

> By industry: Development of suitable feedback systems

Proposed actions

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Pathways for building automation

with focus on nearly zero non-residential buildings

Load shifting and storage management

Energy related use of thermal masses, e.g. to increase free cooling

potentials

> Further research to specifying the potentials for different nearly zero energy

building types in different regions is needed

Grid price related use of thermal masses

> Electricity suppliers should offer (interesting) flexible electricity tariffs

Increase the coverage rates of the energy demand by PV

> Evaluation and publication of best practice examples could increase the

market recognition

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Proposed actions

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Pathways for building automation

with focus on nearly zero non-residential buildings

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Ensuring thermal comfort

> Improvement and development of standardized control mechanisms,

specialized to control slow reacting systems in nearly zero energy buildings

(e.g. by using weather forecasts)

Proposed actions

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Thank you for your attention

For more information, please contact:

> Markus Offermann

Ecofys Germany

Am Wassermann 36

50829 Cologne

Germany

E: m.offermann@ecofys.com

I: www.ecofys.com

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