Energy Efficiency in Irish Office Buildings A Current Perspective German - Irish Chamber of Commerce 7th October 2008

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GermanGerman -- Irish Chamber of CommerceIrish Chamber of Commerce
77thth October 2008October 2008
__________________________________________________________________
Energy Efficiency in Irish Office BuildingsEnergy Efficiency in Irish Office Buildings
A Current PerspectiveA Current Perspective
Bill QuigleyBill Quigley
DirectorDirector
NuTech Renewables LtdNuTech Renewables Ltd
Carbon emissions and Energy Supply in IrelandCarbon emissions and Energy Supply in Ireland
•• It is the considered view by all the EU Member States that ClimaIt is the considered view by all the EU Member States that Climatete
Change must now be tackledChange must now be tackled
•• Studies have shown that failure to do so could mean a radicalStudies have shown that failure to do so could mean a radical
change in life on this planet as we know itchange in life on this planet as we know it
•• Most recently the Stern Report in the UK has called for immediatMost recently the Stern Report in the UK has called for immediatee
actionaction
•• The Irish Government also has a seriousThe Irish Government also has a serious
problem in terms of the Security of Supplyproblem in terms of the Security of Supply
issueissue –– 87% of our energy will be imported for87% of our energy will be imported for
the next 20 years (Source: SEI)the next 20 years (Source: SEI)

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Possible effects on Ireland?Possible effects on Ireland?
•• Montreal is the same Latitude as:Montreal is the same Latitude as:
…………..LYON!!!!..LYON!!!!
•• Ireland is the same Latitude as Hudson Bay in CanadaIreland is the same Latitude as Hudson Bay in Canada
•• If the North Atlantic Drift switches off OR weakensIf the North Atlantic Drift switches off OR weakens
thenthen
……..get your dog sled ready!..get your dog sled ready!
•• ThisThis probablyprobably happened beforehappened before -- there was a mini icethere was a mini ice
age in Shakespeareage in Shakespeare’’s times time
Total Primary Energy Requirement by SectorTotal Primary Energy Requirement by Sector -- IrelandIreland
(Source(Source –– SEI)SEI)

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Total Primary Energy Requirement by SectorTotal Primary Energy Requirement by Sector -- IrelandIreland
(Source(Source –– SEI)SEI)
Residential is 24.5% of total; Services are 15.9%Residential is 24.5% of total; Services are 15.9%
ElectricityElectricity –– Emissions and EfficiencyEmissions and Efficiency (Source(Source –– SEI)SEI)

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Passive HousesPassive Houses
Very Low Energy DemandVery Low Energy Demand
RequirementsRequirements
(a)(a) less than 15 kWh/m2.Yearless than 15 kWh/m2.Year
(b)(b) Less than 10W/m2 heating loadLess than 10W/m2 heating load
(c)(c) Air Infiltration 0.6 ACH at 50PaAir Infiltration 0.6 ACH at 50Pa
= 0.03 ACH at Normal Pressure= 0.03 ACH at Normal Pressure
Mechanical HRV systemsMechanical HRV systems
PriorityPriority –– get a highly efficient HRV unit with a low Specific Fan Powerget a highly efficient HRV unit with a low Specific Fan Power
To design a highly efficient HRV unit you do two things
1. Have a large Heat Exchange Area
and
2. Move the air slowly through the heat exchange unit i.e. you are moving less air
Passive houses are required to have an Air Infiltration rate of < 0.6 ACH @ 50Pa
Passive House Design looks for a Fresh Air input of 0.3 ACH – this is very low.
In an 85m2 house its Volume is say 220 m3 and therefore the amount of Fresh Air
incoming is 72.6 m3 per hour – that is 20.12 litres of air per second.
ASHRAE advise 12 litres of fresh air per person per second…..????
Care is required

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Nursing Homes and Schools – a modular solution
••Design a modular system to provide solar assisted ventilationDesign a modular system to provide solar assisted ventilation
••Can double the amount of solar energy per square metreCan double the amount of solar energy per square metre
••Most useful in Nursing Homes and Schools and small officesMost useful in Nursing Homes and Schools and small offices
The more solar
collectors we use
on the roof – more
energy we save
WITHOUT any
implications for
Summer
overheating
Solar Collectors andSolar Collectors and IrishIrish WeatherWeather
Example:
Q = Ac Fr [(τ .α.. I) – UL(Ti – Ta)]
I = Level of Solar Radiation ; UL = Heat Loss from Collector
Ti = Inlet Fluid Temperature; Ta = Ambient Air Temperature
So, If Ti = 30 C and Ta = 5 C then the DT = 25
For a Flat Plate Collector if the UL is 5 W/m2.K then the UL(Ti-Ta) term is 125 Watts.
This means that when all the other factors are taken into account it will never operate
below say 200 W/m2 of solar radiation
For the Evacuated Tube Collector the UL is say 1.2 W/m2.K then the UL(Ti-Ta) term is
27.5 Watts
Clearly then, the Evacuated Tube works better in the Irish Winter provided you have a use
for the low level temperature that is generated

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Solar Collectors andSolar Collectors and IrishIrish WeatherWeather
Example Continued:
Q = Ac Fr [(τ .α.. I) – UL(Ti – Ta)] Ac = 5m2; Fr = 0.9; τ = 0.92; α = 0.95
I = 200 W/m2 Level of Solar Radiation ; UL = 1.2 W/m2.K Heat Loss from Collector
Ti = 30 C Inlet Fluid Temperature; Ta = 5 C Ambient Air Temperature
The Q = 663 Watts
If air exiting house to the HRV is 20 C and incoming ambient air is 5 the air off the HRV
unit will be approx 18 C
Assume the air flow through the HRV unit is 103 litres per second (370 m3 / hr)
This is heated by the solar water to air heat exchanger and the air to the house is then at
approx 24 C.
NOTE: The incoming air is now warmer than the exiting air. We are now heating the
house with the HRV system
NuTechNuTech
Computer SimulationComputer Simulation -- TemperatureTemperature
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Temperature(o
C)
TH1
TCONC
TLW
Nursing Home - Timber Frame building - insulated, HRV, Air Solar Collectors

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Irish Office BuildingsIrish Office Buildings
••Passive Solar storage in the concrete slabsPassive Solar storage in the concrete slabs
••Temperature to exceed 25 C less than 5% of the timeTemperature to exceed 25 C less than 5% of the time
••Energy UseEnergy Use –– 76.4 kW/m2.yr ( a 70% improvement on a natural ventilated offic76.4 kW/m2.yr ( a 70% improvement on a natural ventilated office ande and
87% on a partially airconditioned building)87% on a partially airconditioned building)
••Most areas are naturally ventilatedMost areas are naturally ventilated –– except for the Council Chamber!except for the Council Chamber!
••Air movement does not exceed 0.8 m/secAir movement does not exceed 0.8 m/sec
Irish Office BuildingsIrish Office Buildings –– Limerick County hallLimerick County hall

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Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall
Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall
TemperaturesTemperatures
not to exceednot to exceed
26 C for more26 C for more
than 2.5% of thethan 2.5% of the
time duringtime during
office hoursoffice hours

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Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall
Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall

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Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall
Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall

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Irish Office BuildingsIrish Office Buildings
••Energy savings to be in the region of 80% of similar school to nEnergy savings to be in the region of 80% of similar school to normal designormal design
••Passive solar architecturePassive solar architecture –– pick up sun in morningpick up sun in morning
••Improved insulationImproved insulation
••Reduced air infiltrationReduced air infiltration
••Natural ventilationNatural ventilation
••Heat pumpHeat pump –– underfloor heating at night rate electricityunderfloor heating at night rate electricity
Irish Office BuildingsIrish Office Buildings

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Irish Office BuildingsIrish Office Buildings
Thank you for listeningThank you for listening…………
Bill QuigleyBill Quigley
NuTech RenewablesNuTech Renewables
Tel:Tel: 01. 663 63 7201. 663 63 72
Fax:Fax: 01. 663 63 7301. 663 63 73
Mobile:Mobile: 086 88 363 99086 88 363 99
ee--mail:mail: bill.nutech@gmail.combill.nutech@gmail.com
Web:Web: www.nutechrenewables.comwww.nutechrenewables.com
Factory / Showroom: Tel:Factory / Showroom: Tel: 048 4175 30 31048 4175 30 31
Fax:Fax: 048 4175 41 51048 4175 41 51