examples of nzeb in the public sector by john furlong

Workshop on the Public Sector Nearly Zero Energy Building (NZEB)

Interim Specification

Aisling Hotel, 30th January, 2017

John Furlong, OPW M&E Services

John Furlong

Examples of NZEB in the

Public Sector

AGENDA

(1) Recap on Current Experience:

Recently Completed Project:

Special Olympics HQ

(2) Example of NZEB in the Public Sector

Pre Construction:

Leeson Lane Office Building

Pre-NZEB NZEB

(1) Recap on Current Experience : Special Olympics Head Quarters

SPECIAL OLYMPICS HQ, (1,700 m2)

- National Sports Campus, Abbotstown

- Single Storey Office Building

- Completed in October 2016

- Building Energy Rating: A3


Comparison with Interim NZEB Specification

Element Unit NZEB Special Olympics

Roof U Value W/m2.k 0.15 0.15

Wall U Value W/m2.k 0.18 0.20

Floor U Value W/m2.k 0.15 0.16

Window U Value W/m2.k 1.4 1.8

G-Value % 40 33

Light Transmittance % 71 60

Percentage Glazing % 40 ~50

Air Permeability m3/m2.hr 3 Design 3: Actual <5

Lighting lumminiare lumen / circuti Watt 65 (81.25) 95

Occupancy Control - Yes Yes

Daylight Control - Yes Yes

BU

ILD

ING

EN

VEL

OP

EEL

EC


Review of Lighting Luminaire Performance


Review of Lighting Lumminare Performance

Area Served Illuminance Lumminaire Type

NZEB Requirement Actual Achieved

(Lux) (Lumens / Circuit Watt) (Lumens / Circuit Watt)

Open Plan Office 500 Lux LED 81.25 95

Cellular Single Office 500 Lux LED 81.25 95

Canteen 300 Lux LED 81.25 118

Store 200 Lux LED 81.25 79

Meeting Room 500 Lux LED 81.25 95

Toilets 200 Lux LED 81.25 85

Plant Room 300 Lux Flourscent (T5) 81.25 79

Circulation 200 Lux LED 81.25 87

Building Average 81.25 94

Luminous Efficacy


Comparison with NZEB Interim Specification

Element Unit NZEB Special Olympics

Heating Effeciency % 91

96 %

Condensing Gas Fired

Boilers

Central SFP - 1.8 1.4

Terminal Unit SPF - 1.8 N/a

Cooling (SSEER) - N/aDX Units in Comms

Rm & Meeting Rm

Variable Speed Fans

& Pumps- Yes

Yes,

(EEI: <0.2) [~60%]

Demand Control

(Mech. Ventilation

only) Variable

Speed control of

fans via CO2 sensor

- Yes

No.

(Natural Ventilation)

(Toilets:- Heat

Recovery)

Mec

hanc

ial



0

0.2

0.4

0.6

0.8

1

1.2

EPC CPC BER

Comparison of EPC, CPC & BER under Part L 2008, SOI Actual and Interim Specification with No Renewables

Part L 2008 Actual Interim Spec

* Data provided by Sustainable Energy Solutions (SES) for OPW M&E Services

A3 A3

1.0

TGD Part L 2008

TGD Part L 2008

TGD Part L 2008

B1

0.66 0.66



0

0.2

0.4

0.6

0.8

1

1.2

EPC CPC BER

Comparison of EPC, CPC & BER under Part L 2008, SOI Actual and Interim Specification with Renewables

Part L 2008 Actual Interim Spec

A3

A3

1.0

15%

* Data provided by Sustainable Energy Solutions (SES) for OPW M&E Services

B1

0.51

0.66

TGD Part L 2008

TGD Part L 2008

TGD Part L 2008



52%

1% 5%

19%

23%

Actual Building Delivered Energy

Heating

Cooling

Auxillary

Lighting

Hot Water


Comparison with NZEB Interim Specification: Possible Renewable Options Considered

Option Heating Cooling Auxillary Lighting Hot Water Renewable EPC CPC RER NZEB

% Compliant

Biomass Boiler to provide Heating

and Hot Water

64 1.69 5.73 23.16 27.84 83 0.66 0.39 50 No

Photovoltaics (265 m2) 64 1.69 5.73 23.16 27.84 15.62 0.5 0.5 20 Yes

kW.hr.m2.yr

Photovoltaic Panels:

- Could be located on the roof as indicated.

- Approximate Cost: €55,000 (110 Panels, 1.5 x 1 m, 220 W/panel, 24 kWhrp 220 m2) .

- Planning and Architectural Considerations


Comparison with NZEB Interim Specification: Possible PV Locations

Approx. 220 m2

Ap

pro

x. 1

50 m

2

(2) Example of NZEB in the Public Sector : Leeson Lane Office Building

Approach to NZEB in Leeson Lane (Mid 2016)

1. Establish the Requirements.

- NZEB and Part L requirements were somewhat unknown.

- Refer to DHPCLG Report “Towards Nearly Zero Energy Buildings In Ireland, Planning for 2020 and Beyond”

which states:-



1. Design Team Target:

To achieve a 60 % improvement on TGD Part L (2008) performance levels by addressing the building envelope,

Mechanical and Electrical services initially and then to consider what further improvements could be achieved

using renewable energy on site.

2. Key Issues:-

• How to achieve a 60 % improvement on TGD Part L (2008)?

• How to treat the building? Naturally ventilated or Air Conditioned?

• How to accommodate the Mechanical and Electrical Services to comply with the Dublin City Council

Planning Guidelines?

• How to achieve a flexible design to allow air conditioning to be added to some or all zones in the future if

required?



1. Natural Ventilation

2. 40 % improvement on the TGD Part L (2008) performance levels could be readily achieved.

3. Therefore the primary key challenge was to investigate if a further 20 % improvement could be achieved and the

following aspects were considered:-

1. Improved Air Tightness

2. Improved U-Values

3. Extent of Glazing & Glazing Specification

4. Improved Plant Efficiencies

5. Improved Lighting System Efficiencies

6. Review of Thermal Bridging

7. Introduction of Renewables



1. Improved Air Tightness:

• Air Tightness Levels approaching 1.0 ACH or 0.6 ACH such as in Passive Haus will lead to the following

challenges:-

• Better detailing and air tightness membrane and seals around services will be essential.

• Heat recovery ventilation will be required to remove pollutants, odours, moisture and provide fresh

air for occupants.

• Site supervision during construction to ensure that details are carried out correctly and mandatory

testing to prove that design is met. Possibly a contract mandating the contractor to carry out remedial

measures to achieve acceptable maximum levels if necessary.

• Potential increased overheating in the absence of night purging.



1. Improved Air

Tightness

The improved building air

tightness levels have given

rise to increased difficulties

in being able to cool the

building in Summer time

as illustrated here.

Resultant Temperature

22nd June 3pm Resultant

Temperature

* Data provided by

Sustainable Energy

Solutions (SES).



1. Improved Air

Tightness

No night time purging


22nd June 3 AM Resultant

Temperature

* Data provided by

Sustainable Energy

Solutions (SES).



1. Improved Air

Tightness

With night

time

purging


22nd June 3 AM Resultant

Temperature

* Data provided

by Sustainable

Energy Solutions

(SES).



1. Improved Air

Tightness

With night

time

purging


22nd June 3 PM Resultant

Temperature

* Data provided

by Sustainable

Energy Solutions

(SES).



2. U-Values:

• U-Values have improved since the introduction of TGD Part L 25 years ago.

• Currently 40 mm of rigid phenolic foil faced partial fill cavity wall insulation can achieve the current backstop U-

Value and 100 mm to 130 mm will achieve the proposed interim U-Value, however approximately 240 mm would

be required to achieve 0.1 W/m2.K.

U-Value 1991 1997 2005 2008 NZEB Unit

Walls 0.55 0.55 0.37 0.37 0.18 W/m2.K

Roof 0.35 0.35 0.25 0.25 0.15 W/m2.K

Floor 0.45 0.45 0.37 0.37 0.15 W/m2.K

Glazing 3.6 3.3 2.2 2.2 1.4 W/m2.K



2. U-Values:

• This creates larger cavities, which increases costs and leads to

increased size of relieving angles in curtain wall construction,

which in turn could lead to greater thermal bridging.

• Deeper window reveals can create some difficulties in restricting

natural ventilation openings.

• Spandrel panels are typically 40 to 60 mm and they might

typically achieve a U- Value of 0.35 W/m2.k which would now be

significantly greater than the wall U Value.

• Designers may be forced to consider new phase change

materials like GlassX, which is a translucent element with a U-

Value of 0.48 W/m2.K plus it reflects solar radiation in summer

while allowing solar radiation in during winter and acts as a

thermal mass element.




Smaller Window Area (40 %)

• Reduced Glare

• Increased Lighting Loads

• Windows below working

plane do not add significantly

to light levels

Larger Window Area (60 %

Plus)

• Visual Impact / Natural Light

• Reduced Energy Efficiency

• Increased Heating / Cooling

Loads




Reduce the potential impact on firstly the ability to naturally ventilate the building and secondly to try to achieve

the 60 % improvement on the TGD Part L (2008) and these are given as follows:-

- Extent of Glazing and external Shading devices such as blinds, bre solei and vertical fins.

- Improve the glazing specification such as U-Value, G Value and Light Transmittance Value which included triple

glazing

- Improve the U-Value of the glazing

- Increase the free openable area of the windows



3. Extent of Glazing

75% Glass

75% Glass with External Shading

60% Glass with insulated opaque panels



4) Improved Plant Efficiencies

Variable speed drives, thermal mass, ice bank, demand controlled ventilation

4) Improved Lighting System Efficiencies

LED lighting throughout and externally.

5) Review of Thermal Bridging

Greater focus on thermal bridging

6) Introduction of Renewables

Solar,

CHP

Heat Pumps

Bio Mass



Final Outcome:

The design team collaborated to assess all options and to determine the best overall fit for the project. This

involved an iterative process with the architect drawing up various options for the Simulation Consultant to assess

until a final solution was arrived at.

The final solution resulted in the following key characteristics:-

Envelope / Fabric As indicated below.

Heating & Hot Water: Gas fired condensing boilers, variable speed pumps.

M&E Plant locations

Ventilation: Open plan offices and cellular office areas:

Natural Ventilation & Primary fresh air

Heat recovery & Demand controlled via CO2 sensors.

Renewables: None.


Approach to NZEB in Leeson Lane (Mid 2016) Final Outcome

Element Interim Specification Lesson Lane

Fabric

Roof U Value (W/(m2K)) 0.15 0.1

Wall U Value (W/(m2K)) 0.18 0.35 for insulated spandrel panel

0.1 for all other heat loss walls

Floor U Value (W/(m2K)) 0.15 0.1 for all heat loss floor

Thermal Bridging ACD ACD

Window U Value (W/(m2K)) 1.4 0.8

% glass of Exposed Façade 40% 60%

G-Value (%) 0.4 0.35

Light Transmittance (%) 0.71 0.55

Air Permeability (m3/(m2h) 3 1




Lighting

Lighting 65 Lumen/circuit watt LED (1.6 w/m2/100 lux)

Daylight Control Yes Dimming in all spaces

Occupancy Control Yes Auto On/ Off in all spaces

HVAC

Heating 91% 92% Natural Gas Fired Boilers Variable speed control of fans and pumps Yes Yes

M&T - Monitoring and Targeting on HVAC and

Lighting

Cooling (air-conditioned) (SEER/SSEER)

4.5 SEER/ 3.6 SSEER 2.7 SSEER mixed mode

3.5 SEER/ 2.39 SSEER Mixed Mode cooling FCU system in

Meeting rooms only. 3.5 SEER/ 2.62 SSEER

Cooling Split System in Comms Rm




Ventilation Demand Controlled

S&E Fresh Air only to Offices and Meeting rooms with heat recovery

S&E to WCs and photocopy with heat recovery

Extract from tea station

Central Ventilation SFP (W/(l/s)) 1.8 1.5

Heat Recovery - 80%

DHW

Hot Water Heater 91% 92% Natural Gas

DHW Tank - 2000 litres

Insulation on Tank - 75mm

Secondary Circulation Losses (W/m) - 7



B1

A2

58 % Improvement

over TGD Part L 2008.

Design Exceeds

Interim NZEB

Specification.

TGD

Part L

2008 NZEB

(42 %)

THANK YOU!

examples of nzeb in the public sector by john furlong

Government & Nonprofit