G&S Lisbon Passivoffice Study Trip Notes

Climate Change Adaptation Research

Technologies Strategy Board (TSB)

Passive Office Study Tour, Portugal

April 2012

Notes

Gale & Snowden Architects & Engineers

April 2012

Gale & Snowden Architects Notes from Passive Office Study Tour, Portugal

April 2012 Page 2 of 9

Passivhaus Study Tour

Portugal, April 2012

Notes

Prepared by: Jason Fitzsimmons

Checked by: David Gale

Project: PassivOffice

Version: 1

Date: April 2012

Job No: B1113

Reference: B1113 CCA Passive Office\Reports\Passive Office Portugal Study Tour Notes

Rev No Comments Date

Gale & Snowden Architects Ltd

18 Market Place

Bideford

Devon EX39 2DR

T: 01237 474952

F: 01237 425449

www.ecodesign.co.uk

Company No. 5632356

VAT Registration No. 655 9343 06

Gale & Snowden Architects Notes from Passive Office Study Tour, Portugal

April 2012 Page 3 of 9

1.0 Introduction

The following details the findings and observations from the Gale & Snowden Passive Office visit in

Lisbon Portugal of the Solar XXI building.

2.0 Details of the Passive Office

Building name: Solar XXI and is the National Laboratory of Energy and Geology (LNEG)

Completed: 2006

Floor area: Total: 1500 m2, useful 1000 m2

Building type: Offices and Laboratory

No of Floors: 4 including a basement

2.1 Key features

The building has been designed with the following key features:

Natural ventilation – with cross flow, stack and single sided ventilation with high and low level

openings – all manually controlled. Glazed louvres above doors enabled air to move from the

office space into the stack corridor.

Central full height corridor throughout the building with high level stack openings

Stairwells at either end of the building on the east and west side, both of which have high level

stack openings

Thermal mass in solid floor and internal walls. Walls consisted of an external wall insulation

system. Innovative use of mass in the floor with a channel for floor services.

South facing orientation – maximising solar gain in winter with large south facing double glazed

units

Integrated vertical PV system on the south facing façade with innovative heat recovery from

behind the PV panels to the office space via high and low level openings. Additional pitched PV

system in the adjacent car park area.

Solar hot water panels on the roof for pre-heating a thermal store for heating only. The building

has no hot water supplies.

The design featured 32 x 300mm diameter concrete earth tube system ranging from 5-15 metres

in length at a depth of 4-5 m in the ground. During elevated internal temperatures the fans were

switched on to pull air through the ground to help cool the space.

2.2 Thermal Details

Windows: Double glazed units with a Uvalue of 2.6 W/m2/K. External shading to control solar

gain in summer.

Walls: 220mm masonry brick internal, 60mm EPS insulation external – Uvalue 0.26 W/m2/K

Floors: Concrete and screed on top of 100mm EPS insulation – Uvalue unclear

Roof: Concrete with 100mm EPS on top - Uvalue unclear

Air Permeability: Untested due to warm winter conditions and Portuguese building regulations

Gale & Snowden Architects Notes from Passive Office Study Tour, Portugal

April 2012 Page 4 of 9

Other features: The vertical south facing façade consists of 100m of PV to the external wall. This is

claimed to protect the fabric from solar gain in the summer and also retain heat loss

in the winter.

Designed and built with high internal thermal mass and external insulation to

stabilise internal temperatures and to support night cooling.

2.3 Ventilation Systems

The ventilation systems relied on manual control and a good user understanding of when and how

to operate them as there were various control parameters. The occupants were energy engineers

and building physicists, i.e. highly skilled technically minded occupants. How easy this strategy

would be implemented in offices with less technically minded people would have to be

considered. The system relied on occupants to control solar gain manually via the external blinds,

open and close various vent openings, manually switch on ground cooling.

Ventilation control parameters:

o In winter open both internal high and low level vents and close off vent opening externally to

the PV shaft. This creates a recirculatory air system partly heated via solar gain on the PV

panel. Fresh air would then be via the opening window. This is provided that there is solar

gain in the winter on the PV panel. If there is there would also be solar gain through the

glazing providing useful heat to the space.

o In winter open high level vent internally and external low level vent to PV shaft to drive pre

heated air into the space during periods of solar gain.

o In summer close high and low level openings internally, open both high and low level openings

to external PV shaft to vent behind PV panel.

o In summer opening windows, open louvres above corridor doors and open roof level stack

openings.

o During elevated summer temperatures enable ground cooling system

o In summer night cooling - open high level vent internally and external low level vent to PV

shaft to drive air into the space. Keep stack vents open. This provided a secure night cooling

natural ventilation strategy.

o Night cooling could be boosted by earth tubes and enabling fans.

Earth tube system

The potential issue of condensation forming in the duct and/or bacterial contamination had not been

considered. It was found that even when the fans were not in operation air was moving through the

duct into the building under natural driving forces. This was because there was no means for closing

the system off in an air tight manner when not in use. There could be certain times in the year where

condensation could form on the inner walls of the earth tube. There appeared to be no means to drain

this if it did occur.

The fans to pull air through into each office space were located within the offices; this presented a

potential noise issue when in use.

2.4 Overheating

Monitoring of internal temperatures (see paper Solar XXI Toward Zero Energy) revealed that for

95% of the time internal temperatures did not exceed 270C. This paper does not reveal the

occupancy patterns during the study and it was unclear at the time of the visit as to whether the

Gale & Snowden Architects Notes from Passive Office Study Tour, Portugal

April 2012 Page 5 of 9

building was in full use. If fully occupied with people and PCs internal temperatures may differ to

what has been revealed.

Sufficient strategies had been designed into the building with good use of cross flow and stack

ventilation, mass for night cooling, control of solar gain and ground cooling to enable the building

to operate passively without air conditioning.

In terms of design the building had large glazed areas facing south and issues associated with

overheating were addressed by good solar control which was via external retractable shading on

windows with high solar gain.

2.5 Daylight and solar orientation

Internal corridors were well day lit from the roof glazing system and did not rely on artificial lighting

during the day. The roof glazing was north facing.

Solar orientation - the building had been laid out to optimise solar gain in winter and windows on

these elevations were generous to allow this. The key to ensuring that the building did not

overheat in summer was solar control, which was via external retractable blinds and overhangs.

This is an important element for climate change adaption work as it shows that passive ventilated

offices in warmer climates with large southerly glazing can and does work without air conditioning.

With blinds ¾ down the offices spaces still enjoyed very good daylight levels and did not rely on

artificial lighting. This was observed on a sunny day and it is to be noted that Portugal enjoys

better and higher external light levels than the UK. In a UK context with blinds ¾ down internal

daylight levels might not be so high.

2.6 Design for Future Climate (D4FC) Adaptations

From a D4FC adaption perspective the Solar XXI building has been designed passively on the current

weather files for Lisbon, Portugal and the design did not take into account future climate change in the

same manner as this project. The weather file that would have been used is one that has higher air

temperatures than the UK and exceeds a UK future weather file of 2080 50th percentile. See Figure

12 at the end of this report.

The office did not have air conditioning and was designed and orientated to optimise solar gain in

winter with large glazing areas in a southerly direction. Overheating was controlled through various

strategies which all worked in conjunction with each other - manually controlled ventilation openings,

the use of thermal mass and night cooling, solar control via external shading. Ground earth ducts

were enabled during hotter conditions.

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2.7 Images

Figure 1: South Facing Facade showing vertical PV array, glazed areas and external blinds

Figure 2: Close up of high level opening

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Figure 3: Vertical PV detail with external high and low level openings

Figure 4: High and low level internal openings where PV is located externally.

Figure 5: Stairwell high level actuated openings for stack vent

Grey shutters are the vent openings to the inside and are operated manually. The white bars are pulled to open the external PV shutters or pushed in to close them.

Figure 6: North façade glazing with high and low level openings

Figure 7: Fan systems for earth tubes

These were located in the office space and covered by a panel when not in use. Air movement was felt from the earth tube when the fans were not switched on. The fans emitted noise direct in the office space when switched on.

Gale & Snowden Architects Notes from Passive Office Study Tour, Portugal

April 2012 Page 8 of 9

Figure 8: Glazed ventilation openings from office rooms to corridor to enable stack ventilation. There is no acoustic attenuation.

Figure 9: Glazed ventilation openings from northern office rooms to corridor to enable stack ventilation and allow daylight penetration from roof north lights. There is no acoustic attenuation.

In the northern rooms these were much larger to allow for better daylight penetration as windows in the northern façade were small than on the southern facade.

Figure 10: Eternal intakes for Earth tubes Figure 11: Channel in floor for services to maintain mass in floor and heavy weight construction

Gale & Snowden Architects Notes from Passive Office Study Tour, Portugal

April 2012 Page 9 of 9

Figure 12: Lisbon current summer weather file vs UK 2080 50th percentile

Lisbon weather file, no of hours external air temperature is above 250C = 878 hours

UK weather file 2080 50th percentile, no of hours above 250C = 502 hrs

Green = Lisbon

Red = UK 2080 50%