Opening the door to Nearly Zero Energy Buildings

Author: Michael Hanratty MIEI, managing director, IHER Energy Services Arising from the Recast of the European Performance of Buildings Directive 2010/30/EU), from 1 January 2019, every new public building will have to be designed to nearly zero energy building standards. Also, all other new buildings will have to comply with the new nearly zero energy buildings standards from 1 January 2021. The aim of the Nearly Zero Energy Buildings (NZEB) Open Doors campaign, taking place in 10 countries in Europe in 2014 within the Intelligent Energy Europe programme, is to promote NZEB standards to inspire more people to follow the early adopters. This EU programme was the brainchild a Belgian company, Bond Beter Leefmilieu (BBL), which in 1998 developed the concept of ‘EcobouwersOpendeur’ to inspire builders and home owners to build and renovate their houses to a higher energy standard. Over the past 15 years, more than 33,500 visitors have participated in the Ecobouwers Open Doors Days. It has built a steady reputation as the biggest independent and non-commercial Open House event in the Flanders region of Belgium. In 2012, BBL decided to scale up the initiative and joined organisations from nine other EU member states to develop similar Open Doors events under the common name of NZB2021 Open Doors Days. In 2013, a total of 637 buildings and 11,258 visitors participated in the 10 member states. The Irish partner, Energy Action Limited, ran a very successful campaign in 2013 with more than 60 buildings and 800 visitors. Ireland's second nationwide NZEB Open Doors Days will take place over the weekend of 7 -9 November. Members of the public and building professionals will be provided with a great opportunity to visit some of the best examples of low energy projects, both houses and public/commercial buildings, in Ireland. All visits are free, but do need to be booked in advance through the NZEB Open Doors website. More than 50 buildings will open their doors this year. Commercial/public buildings include the A2-rated Colaiste Choilm in Tullamore; the Irish Distillers Garden Stillhouse in Midleton, Co Cork; CIT’s ZERO2020 building; the NUI Galway Engineering building; a Passive House pharmacy in Clonmel; the TVM building near Fermoy; the Zero Carbon Tesco in Cabra, Dublin 7; Nenagh Swimming Pool; and the Hive Centre in Carrick-on-Shannon. The Irish standards for Nearly Zero Energy Buildings are set out in the Department of the Environment, Community and Local Government’s (DCELG) publication Towards Nearly Zero Energy Buildings in Ireland – Planning for 2020 and Beyond, issued in November 2012.

New dwellings – NZEB

By 2020, all new dwellings in Ireland will have an energy performance co-efficient (EPC) and carbon performance co-efficient (CPC) not exceeding 0.302 and 0.305 (as calculated in the SEAI DEAP BER software) in accordance with framework set out in Annex 1 of Directive 2010/31/EU on the energy performance of building (recast). This takes account of the energy needed for space heating, water heating, fixed lighting and ventilation. For a typical dwelling, this equates to an A2 rating with a primary energy value of 45 kWh/m2/annum with a significant proportion of the energy demand being covered by renewable resources produced on-site or nearby. The progression to improved energy performance since 2005 of dwellings is summarised in Table 1. Table 1: Revisions to Energy Performance of Buildings Standards since 2005

Part L (Average Dwelling)	2005	2008	2011	2016 (NZEB)
% Improvement	Baseline	40%	60%	70%
Primary Energy Consumption (kWh/m²/a)	150	90	60	45
CO2 Emission Rate (kgCO2/m²/a)	30	18	12	10
BER	B3	B1	A3	A2
MPEPC	-	0.6	0.4	0.302
MPCPC	-	0.69	0.46	0.305

The DCELG expects the new NZEB standard for dwellings to come into effect in 2016.

New buildings other than dwellings – NZEB

By 2020, it is proposed that all new buildings other than dwellings will achieve a 50% to 60% improvement in terms of energy efficiency and reduction in CO2 emissions with regard to the energy load for space heating, water heating, cooling, fixed lighting and ventilation. In accordance with the definition for NZEBs under Article 2 of the Directive 2010/31/EU (recast EPBD), a very significant proportion of the building energy demand will be covered by renewable energy sources produced on-site or nearby. The proposed NZEB standards for Buildings other than dwellings are described in Table 2. Table 2: Target typical improvements for buildings other than dwellings

Target	Year	Improvement on TGD L 2008 Building Other than Dwellings Performance Level
Intermediate	2014	40% plus
Final	2020	c.60%

In the public sector, the NZEB standard for buildings other than dwellings will be implemented in 2018, two years in advance of the rest of the market. For Part L 2014 regulations, public buildings will lead by adopting a one-year transition period compared to the normal practice of two years.

Existing dwellings – NZEB

By 2020, the target load for space heating, water heating, fixed lighting and ventilation will be of the order of 125 to 150 kWh/m2/annum excluding renewable energy sources. This equates to a BER rating of C1. In addition, it is expected that a reasonable proportion of the remaining energy use of the dwelling will come from renewable energy sources onsite or nearby. New dwellings NZEB design considerations The DCELG has already commenced work on developing a standard to support the NZEB EPC and CPC levels (0.302 and 0.305 respectively) with regard to further improvements in building fabric (i.e. lower U values), improved thermal bridging details, improved air-tightness and improved ventilation strategies. The Irish Building Typology developed by Energy Action in 2012, under the Intelligent Energy Europe (IEE) TABULA project, identified the main existing dwelling types in Ireland and analysed two levels of retrofit upgrades on each type. The TABULA typology was extended in 2014 under the IEE EPISCOPE project to include new build design variants for TDG L 2011 and the proposed NZEB standard in Ireland (see www.episcope.eu/). In the case of the proposed NZEB standard, a technical guidance document has not yet been published indicating backstop U values. However, as the EPC and CPC levels have been set for the NZEB standard. Three variants were developed by consultants IHER Energy Services Ltd to demonstrate a range of design solutions meeting this standard as detailed in Table 3. [caption id="attachment_17319" align="aligncenter" width="888"]

Table 3: NZEB Design Variants (source: Intelligent Energy Europe EPISCOPE project (2014)[/caption] The first NZEB variant uses higher U values and has a high level of renewable technologies whereas the third variant uses ambitious U values and air permeability levels and a low level of renewable technologies. The second variant provides a midway design solution. The three variants shown give an indication of the types of design combinations that will need to be considered to meet the proposed NZEB standard. Of course, designers will be free to consider a wider range of solutions including different U values, air permeability levels and combinations of heating systems, renewable technologies and onsite energy generation in order to meet the proposed NZEB standard. In addition, the Passive House design principles will also be adopted by many building designers to meet and surpass the NZEB standards. The NZEB Open Doors event is also taking place in Austria, Belgium, France, Germany, Hungary, Malta, Poland, Slovenia and Sweden as part of a wider European initiative. More information is available on www.nzeb-opendoors.ie including short mini-documentaries and inspiring examples from the European partners. The Irish NZEB event will be run in tandem with the International Passive House Days and in partnership with the Passive House Association of Ireland. Michael Hanratty MIEI is managing director of IHER Energy Services, consultant to Energy Action Limited on the Intelligent Energy Europe NZB2021 and EPISCOPE projects.