Isabel Barros Architects - Blog

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Category: Energy (page 1 of 7)

A Passive House Design in Wexford’s Rural Landscape

We are delighted to have achieved Planning Permission for this fantastic project in Wexford.

The site presents a south-facing slope offering open views in a rural landscape. There are large fields surrounding the site, the fields are delineated by native hedges and trees. A number of neighbouring farmyards are also part of the place.

Materials on the neighbouring farm buildings

There is a pattern of materials that is repeated within the area giving it a sense of harmony, these include corrugated metal, rubble stone and white renders.

The south facing aspect of the site offers good access to solar radiation and daylight which are essential for the application of the Passive House standard and passive solar design in general.

DESIGN CONCEPT

The design is strongly related to the landscape and the place.

The proposed site layout is inspired by the nearby traditional courtyard farmyards. 

The proposal uses a contemporary language based on traditional elements and materials.

Three main volumes inspired by traditional forms create a balanced composition with different heights.  The existing rhythm and repetitive pattern of the trees in the northern boundary is reflected in these volumes establishing a strong relationship between the proposed house and the landscape.

The two-storeys volume is conceived to mimic the agricultural buildings in the area. The visual impact is reduced by careful selection of materials that play with mass and weight whilst combining the present with the past.

A simple palette of materials is proposed – white rendered surfaces, notes of rubble stone and grey corrugated metal. The materials aim to connect cultural and local values with a contemporary built environment.

ENERGY PERFORMANCE and SUSTAINABILITY

Passive House Standard
The project’s aspirations include to build a low energy sustainable house guided by the Passive House Standard with a view to achieve full certification by the Passive House Institute.

Passive House is the world‘s leading standard in energy efficient construction. The Passive House Standard stands for quality, comfort and energy efficiency.

Passive Houses stay at a comfortable temperature year-round with minimal energy inputs. Such buildings are heated “passively”, making efficient use of the sun, internal heat sources and heat recovery so that conventional heating systems are rendered unnecessary throughout even the coldest of winters. As energy savings equals emissions reductions, the Passive House is a sustainable alternative to conventional construction.

The house is designed and orientated to maximise passive solar gain and natural lighting. The fenestration facing North is minimal to reduce heat loss. Overhangs to shade south-facing windows are also used to reduce overheating during the summer. The house is carefully positioned to avoid the shade caused by the trees in the northern boundary (2 to 8 metres tall).

Building Energy Rating (BER) and Nearly Zero-Energy Building (nZEB)

The preliminary specifications indicate a Building Energy Rating (BER) of A1 corresponding to an Energy Value of 3.77 KWh/m2/yr. The calculations show an energy performance coefficient (EPC) of 0.024, and a carbon performance coefficient (CPC) of 0.022, which exceeds by far the requirements for a Nearly Zero-Energy Building (nZEB).

Materials and Sustainability

The sustainability strategy also includes the use of timber products manufactured in Ireland from FSC® certified forests managed by Coillte (MEDITE SMARTPLY/ PROPASSIV system).

The choice of corrugated metal takes into consideration the overall environmental impact, performance in use, lifetime durability and maintenance requirements. Many corrugated metal products on the market are made of recycled metal and can be recycled again at the end of their use.

The appropriate fabric specification and an airtight and thermal bridge free design are fundamental to achieve the required Passive House certification.

The external envelope will be highly insulated to Passive House Standards to reduce heat losses. Careful detailing will be essential to achieve the required airtightness and avoid thermal bridges. Energy efficient window glazing units and frames are proposed.

The proposed house is a modern interpretation of the traditional courtyard farmyard. The house aims to use a contemporary architectural language inspired by traditional elements and materials of the rural vernacular architecture.

The design creates visual and physical connections with its surroundings. We believe the proposed development acknowledges, respects and enhances the existing character and landscape without creating an adverse visual impact.

Our design approach considers that Passive House buildings do not have to compromise on their design quality. The idea of creating a unique Passive House drawing strongly from the local vernacular forms and materiality has been paramount to this project.

All New Homes Will Be Nearly Zero Energy Buildings (NZEB)

Amendments to Part L of the Building Regulations (relating to the conservation of fuel and energy in dwellings) will come into effect on 01 November 2019.

All new homes will have a typical Building Energy Rating (BER) of A2 and will be 70% more energy efficient and emit 70% less carbon dioxide than 2005 performance levels.

What is a Nearly-Zero Energy Building (NZEB)?

‘Nearly zero-energy building’ means a building that has a very high energy performance. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby.

Are there any exceptions to the new regulations?

Yes, but only if planning approval or permission has been applied for on or before 31st October 2019 and substantial work has been completed by 31st October 2020.

“Substantial work has been completed” means that the structure of the external walls of the dwelling has been erected.

 What are the key changes to TGD L Dwellings 2019?

  • MPEPC (Maximum Permitted Energy Performance Coefficient)=0.30, in order to achieve the acceptable primary energy consumption rate.
  • MPCPC (Maximum Permitted Carbon Performance Coefficient)=0.35, to demonstrate that an acceptable CO2 emission rate has been achieved.
  • Where a dwelling undergoes major renovation, the energy performance of the whole dwelling should be improved to Cost Optimal level insofar as this is technically, functionally and economically feasible.
  • Introduction of a Renewable Energy Ratio (RER) of 20%.
  • Reduction of air permeability backstop from 7m3 /hr/m2 to 5m3 /hr/m2.
  • Table 1- Reduction of wall and floor backstop U-Value from 0.21W/m2K to 0.18 W/m2K.
  • Table 1- Reduction of window backstop U-Value from 1.6 W/m2K to 1.4 W/m2K.
  • Inclusion of guidance to avoid overheating in dwellings.
  • Par 1.3.2.4 – removal of variation of U-Value with percentage glazing.
  • Introduction of calculation of Ru value for corridors in apartments.

How can compliance be achieved?

The correct specifications need to be prepared by your Architect to your specific project. Compliance is then demonstrated using the DEAP (Dwelling Energy Assessment Procedure) software.

Below is an example prepared by the Department of Housing, Planning and Local Government for a semi-detached dwelling with 126 sq.m. and with heat pump for space heating and continuous mechanical extract ventilation.

NZEB example specification
Semi-detached dwelling with 126 sq.m. and with heat pump for space heating and continuous mechanical extract ventilation

A nearly zero energy buildings (NZEB) future – Minister English reminds construction sector to be prepared for new building regulations on energy efficiency

What’s All the Fuss About the Revised Energy Performance of Buildings Directive

Overview of Key Changes to TGD L – Dwellings 2019

What’s All the Fuss About the Revised Energy Performance of Buildings Directive

The amendment of the Energy Performance of Buildings Directive (EPBD) is one of the most important changes that has occurred in the EU buildings sector in the last 16 years.

Under the revised Energy Performance of Buildings Directive (EPBD):

  • EU countries will have to establish stronger long-term renovation strategies, aiming at decarbonising the national building stocks by 2050, and with a solid financial component.
  • A common European scheme for rating the smart readiness of buildings, optional for Member States, will be introduced.
  • Smart technologies will be further promoted, for instance through requirements on the installation of building automation and control systems and on devices that regulate temperature at room level.
  • E-mobility will be supported by introducing minimum requirements for car parks over a certain size and other minimum infrastructure for smaller buildings.
  • EU countries will have to express their national energy performance requirements in ways that allow cross-national comparisons.
  • Health and well-being of building users will be promoted, for instance through an increased consideration of air quality and ventilation.

Other requirements under the Energy Performance of Buildings Directive include:

  • All new buildings must be nearly zero-energy buildings by 31 December 2020.
  • Energy performance certificates must be issued when a building is sold or rented, and they must also be included in all advertisements for the sale or rental of buildings.
  • EU countries must establish inspection schemes for heating and air conditioning systems or put in place measures with equivalent effect.
  • EU countries must set cost-optimal minimum energy performance requirements for new buildings, for the major renovation of existing buildings, and for the replacement or retrofit of building elements (heating and cooling systems, roofs, walls and so on).
  • EU countries must draw up lists of national financial measures to improve the energy efficiency of buildings.

What is the challenge?

  • The Commission reached an agreement that includes a binding energy efficiency target for the EU for 2030 of 32.5%.
  • The risk of the directive being ineffective is high if countries and local authorities do not enforce it correctly.
  • Around 200 million buildings need to be renovated. EU countries must make energy efficient renovations to at least 3% of the total floor area of buildings owned and occupied by central government.
  • EU governments should only purchase buildings which are highly energy efficient.
  • EU countries must draw up long-term national building renovation strategies which can be included in their National Energy Efficiency Action Plans.
  • Member states are to provide for set system requirements in respect to installation, sizing, adjustment and controls. This applies to heating systems, hot water, air conditioning and large ventilation systems.
  • Cost optimal performance – the integration between cost optimality and high performance technical solutions underpins the deployment of NZEBs.

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