Energy Efficiency In Irish Office Buildings

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Energy Efficiency in Irish Office Buildings

A Current Perspective

German - Irish Chamber of Commerce
7th October 2008

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Energy Efficiency In Irish Office Buildings

  1. 1. 1 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)
  2. 2. 2 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)
  3. 3. 3 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)
  4. 4. 4 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
  5. 5. 5 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
  6. 6. 6 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 10 11 12 13 14 15 16 17 18 19 20 21 22 00:00 01:20 02:40 04:00 05:20 06:40 08:00 09:20 10:40 12:00 13:20 14:40 16:00 17:20 18:40 20:00 21:20 22:40 Temperature(o C) TH1 TCONC TLW Nursing Home - Timber Frame building - insulated, HRV, Air Solar Collectors
  7. 7. 7 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
  8. 8. 8 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
  9. 9. 9 Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall
  10. 10. 10 Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall Irish Office BuildingsIrish Office Buildings –– Fingal County HallFingal County Hall
  11. 11. 11 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
  12. 12. 12 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

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