examples of nzeb in the public sector by john furlong
TRANSCRIPT
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
(1) Recap on Current Experience : Special Olympics Head Quarters
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
(1) Recap on Current Experience : Special Olympics Head Quarters
Review of Lighting Luminaire Performance
(1) Recap on Current Experience : Special Olympics Head Quarters
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
(1) Recap on Current Experience : Special Olympics Head Quarters
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
(1) Recap on Current Experience : Special Olympics Head Quarters
Comparison with NZEB Interim Specification
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
(1) Recap on Current Experience : Special Olympics Head Quarters
Comparison with NZEB Interim Specification
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
(1) Recap on Current Experience : Special Olympics Head Quarters
Comparison with NZEB Interim Specification
52%
1% 5%
19%
23%
Actual Building Delivered Energy
Heating
Cooling
Auxillary
Lighting
Hot Water
(1) Recap on Current Experience : Special Olympics Head Quarters
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
(1) Recap on Current Experience : Special Olympics Head Quarters
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:-
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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?
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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.
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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).
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
1. Improved Air
Tightness
No night time purging
Resultant Temperature
22nd June 3 AM Resultant
Temperature
* Data provided by
Sustainable Energy
Solutions (SES).
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
1. Improved Air
Tightness
With night
time
purging
Resultant Temperature
22nd June 3 AM Resultant
Temperature
* Data provided
by Sustainable
Energy Solutions
(SES).
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
1. Improved Air
Tightness
With night
time
purging
Resultant Temperature
22nd June 3 PM Resultant
Temperature
* Data provided
by Sustainable
Energy Solutions
(SES).
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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.
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
3. Extent of Glazing & Glazing Specification
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
3. Extent of Glazing & Glazing Specification
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
3. Extent of Glazing
75% Glass
75% Glass with External Shading
60% Glass with insulated opaque panels
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016)
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.
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016) Final Outcome
Element Interim Specification Lesson Lane
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016) Final Outcome
Element Interim Specification Lesson Lane
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
(2) Example of NZEB in the Public Sector : Leeson Lane Office Building
Approach to NZEB in Leeson Lane (Mid 2016) Final Outcome
B1
A2
58 % Improvement
over TGD Part L 2008.
Design Exceeds
Interim NZEB
Specification.
TGD
Part L
2008 NZEB
(42 %)