Green Buildings: Challenges and Solutions for Cyprus

Green buildings – Basic Parameters Presented by: CONSTANTINOS XICHILOS ENERGY SERVICE MINISTRY OF COMMERCE, INDUSTRY & TOURISM Nicosia October 20, 2010 [email protected] www.mcit.gov.cy

Introduction (1)  

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The building sector is very important for EU

Represents 40% of total final energy consumption; in Cyprus is about 37% Excellent opportunity for energy conservation measures Energy conservation and the application of RES in buildings can greatly assist Cyprus to meet the EU targets of 2020 on energy conservation, reduction of greenhouse emissions and the use of RES New (Recast) of EPBD; very ambitious MS have to take measures to ensure that by 31 December 2020 all new buildings are nearly zero energy buildings! “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 significant extent by energy using renewable sources produced in site or nearby

Introduction (2) 

A Green building OR

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A Low Energy building OR

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A High Efficiency building OR

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An Almost Zero Energy building

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a Passive Design building

Passive Design seeks to provide indoor comfort (heat, cold, ventilation and lighting) by using and controlling the natural energy flows which surround a building such as solar radiation and wind, with the objective to minimize fossil fuel energy consumption It moderates successfully the internal environment of a building according to the season by virtue of its design (manipulation of the shape, disposition of openings, thermal performance of materials)

Introduction (3) 

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In Cyprus, „imported‟ modern architecture has aggressively replaced traditional architecture which was friendly to the environment and based on passive design approach As a result decades of experience and tradition have been thrown away and ignored

Some architects today are just designing and engineers are obliged to specify „active‟ (mechanical) devices of appropriate size to cover the needs In 1995 the Passivhaus Institut has developed and implemented successfully a passive approach to a house design for central European climates which is very efficient and meets year-round comfort criteria “Ten years ago no-one believed us that houses can manage with less that a tenth of the heating energy used by average old buildings”– Proffesor W. Feist

Introduction (4)

The Passivhaus Standard 

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After the big success, the passive design for central Europe was codified into the Passivhaus Standard – it consists of an energy limit, a quality requirement and a defined set of preferred Passive Systems

The concept of Passivhaus has been a success because is a well defined product, understood by all interesting partners (developer, architect, owner) The Passive House is a Method, not a building style; the principle behind it is based on the concept of reducing investment through energy efficient design Consider the example of a house for a cold climate where the major energy demand is for heating. If this demand is drastically reduced to 10 W/m2 by means of thermal insulation, super-windows, passive solar gains, heat recovery, etc. the traditional heating system can be simplified and replaced by a low cost ventilation system

The Passive House Concept

The Passive-On Project (1) 

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Can the success of the Passivhaus in central Europe be extended to south Europe?

Can we have a Mediterranean Passivhaus and a Mediterranean Passivhaus Standard?

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Passive-On project (2004-2007) under IEE program

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5 partners (France, Portugal, Spain, Italy, UK)

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Aim: To propose an affordable house design for each country in order to meet the criteria of the Mediterranean Passivhaus Standard, i.e. Heating criterion: Useful energy demand for space heating ≤ 15 kWh/m2 of NHFA per year

Cooling criterion: Useful sensible energy demand for space cooling ≤ 15 kWh/m2 of NHFA per year Primary energy criterion: Total primary energy demand (incl. domestic electricity) ≤ 120 kWh/m2

The Passive-On Project (2) 

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Air tightness criterion: ≤ 1.0 per hour (≤ 0.6 when mechanical ventilation system is used) allowing a Passive House to built to the Passivhaus standard without the need for active ventilation system Comfort criterion room temperature winter: ≥ 20 ⁰C

Comfort criterion room temperature summer: Indoor summer temperatures not to exceed the Adaptive Comfort temps as defined in EN 1525 NOTE: The Adaptive Comfort Model considers a wider range of temperatures as “comfortable” allowing easier integration of passive cooling technologies Applying the Adaptive algorithm defined in EN 15251 typical annual weather data predicts max summer neutral temps (in correspondence with a sequence of hot days) for Frankfurt, Milan, Lisbon and Seville as respectively 26.1°C, 27.2°C , 26.7°C, and 28.7°C 

The Passive-On Project (3) 

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As a comparison, a building cooled by an active A/C system will work to a fixed set point chosen between 23°C and 26°C PROJECT REMARKS For each participating country a Passive Design house was identified which allows meeting the criteria of the standard in a cost effective and practical way

On average a Passivhaus costs 4-6% more to build than the standard alternative (Table 1) BUT… Considerable savings on heating and cooling bills could be achieved (Table 2) With typical energy prices the reduction in bills repays the extra cost in less than 20 years (4 years in most favorable situations)

Table 1: Extra Cost of Passivhauses Specific Construction Costs (€/m2) Standard House

% Increase

Passive House

Germany

1.400

1.494

6.71

Italy (Milan)

1.200

1.284

7.0

France

940

1.034

10.0

Spain (Seville)

720

740

2.85

Portugal

800

858

7.15

UK

881

930

5.54

Table 2: Heating and Cooling demand for new houses constructed according to minimum standards of MS and the Passivhaus standard Heating demand (kWh/m2 per year)

Cooling demand (kWh/m2 per year)

Standard

Passive

Standard

Passive

Germany

90

15

0

0

Italy

111

10.5

4.63

3

France

69.6

17.4

n/a

5

Spain

59

8.7

23.1

7.9

73.5

5.8

32

3.7

59

15

0

0

Portugal UK

Cyprus Passive House? 

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Can we have in Cyprus a Passive Design house capable to meet the criteria of the Mediterranean Passivhaus Standard in a cost effective and practical way?

What steps shall we follow in order to develop such a Passive House? Remember: A specific design might be appropriate in one location but not appropriate in another location within the same country (or town) Boundary conditions for each region: (a) local building traditions; (b) specific climatic conditions

Fact: Cooling is our main concern Goal: Reduce cooling/dehumidification demand to such a point that an appreciable simplification occurs of the active technology needed Strategy: Use passive approach and technologies

Suggested Passive Strategies (1) 

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Building shape – Medium compactness (1.3) to reduce cooling demand and to have more glazing oriented to S Building orientation – Long axis oriented to S, thus increasing solar heat gains in winter. Rule of thumb: glazing on the S: 20% of floor area; glazing on the N: 5%. Use overhangs on the S windows for summer protection Shading – Allow solar radiation to reach the building in winter and block the radiation in summer. Avoid large E & W openings because it is difficult to shade them properly Thermal insulation – Roofs U=0.35 W/m2.K (8cm thickness of insulation), Walls U=0.45 W/m2.K (6cm) Windows – Simple double glazing with thermal break U=2.9 W/m2.K External shutters – on all windows

Suggested Passive Strategies (2) 

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Thermal bridges – Considerable impact on the heating energy need (as much as 30%). Could be eliminated by wrapping the exterior surfaces with continuous insulation Thermal mass – Is a considerable advantage for summer and winter because is smoothing out the variation in temp within the building; in winter it used to store solar heat gains during day and in summer it is used to store the night cooling effect

Use of solar water heater for domestic hot water Use of low temperature solar water heating system for space heating

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Passive cooling techniques – see sketches

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Natural ventilation techniques – see sketches

Passive Cooling – Night-time cooling

Passive Cooling – Evaporative cooling

Passive Cooling – Ground cooling

Natural Ventilation – Single sided

Natural Ventilation – Cross ventilation

Natural Ventilation – Stack ventilation

The Parametric Study Method (1) 

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Perform a computer based parametric study of the suggested building design solutions; check the results for energy demand, financial investment and indoor comfort Use as a starting point a „usual‟ building design that conforms with existing minimum requirements

Use appropriate software tools like the Passive House Planning Package (PHPP) Modify one-by-one each important element on the design: external walls, roofs, windows, floor, night ventilation etc. and take notice of the effects Consider parameters like the color (solar absorption coefficient) of exterior walls and roofs, the longwave emissivity of external surfaces, the effect of varying internal mass and internal loads

The Parametric Study Method (2) 

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Propose a design which fulfills the requirements of the standard; but should not be the exclusive solution Architects should be free to choose alternative Passive Designs; however the energy consumption and comfort requirements of the standard must be guaranteed Check the economics of the proposed solution Pay-back times and Rate of Returns become less important and may be irrelevant because of improved living conditions offered to occupants After all, no family ever pretends that luxury kitchen cupboard in a house costing €10.000 more than a good quality cheaper alternative somehow pay itself back

Passive House Supportive Mechanisms 

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Pilot projects – prove the successfulness of the Passive House under the specific climatic conditions

Certification – For the building and the professionals (designers & contractors) Education and training – To all players (designers, architects, engineers, builders, contractors, consumers, real estate, product manufacturers, R&D Financial mechanisms – Financing tools are important; 5% more on construction means €10.000 which is a considerable amount for many families

Information and communication – To all stakeholders about the benefits of Passive Houses Supporting passive design in regulations – High insulation levels for PH means thicker walls; means less useful floor area; so municipality fees and rates should be based on net, not gross house volume

References  

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Passive-On project – Final report, June 2007 First Steps: What can be a Passive House in Your Region with Your Climate by Dr. Wolfgang Feist, Passive House Institute EPBD Directive