Passive House Seminar for Professionals from the Building Sector

DAY 1

Passive House Seminar for Professionals from the Building Sector - Solar Energy Utilization Design

Passive House Seminar for Professionals from the Building Sector Day 1 What is a Passive House? Design According to the Passive House Criteria Design – Heating Systems and Energy Supply Design – Solar Energy Utilization Planning and Concept Development Realization and Construction Processes Basic educational course about Passive Houses, organised by a local partner in the European funded PASS-NET project Passive House Seminar for Professionals from the Building Sector Day 1Design – Solar energy utilization Day 2 Planning and Calculations – introduction to PHPP Energy Statistics, Standards and Certifications Design – Air tightness Design – Ventilation systems Design – Windows Regional examples of built Passive Houses

Passive House Seminar for Professionals from the Building Sector Design – Solar energy utilization and daylight Solar energy in general can have positive but also negative impacts on the building.  Positive : provides energy which can be taken advantage of –Passively - solar heat gains –Actively – active solar systems  Negative: may cause overheating, when shading measures is lacking or inadequate Solar energy utilization is one of the key points in passive house design. Day 1Design – Solar energy utilization

Passive House Seminar for Professionals from the Building Sector Design – solar energy utilization and daylight Solar heat gains through glassed surfaces can provide 10-60kWh/m 2 annually depending on location and building practice of the house. Source: iEPD SOLAR ENERGY UTILIZATION PASSIVE SOLAR HEAT GAINS THROUGH GLASSED SURFACES DAILY STORAGE IN THERMAL MASS Day 1Design – Solar energy utilization

Passive House Seminar for Professionals from the Building Sector Design – solar energy utilization and daylight Various active solar systems, mostly based on solar panels, can cooperate in hot water preparation and air heating or cooling as a part of HVAC concept of the building. Photovoltaic cells can partially or fully cover the electricity demand of the building. Source: iEPD SOLAR ENERGY UTILIZATION ACTIVE SOLAR HEATING OR COOLING SYSTEMS AND PHOTOVOLTAIC STORAGE IN ACCUMULATION TANKS BATTERIES AND DIRECT USE Day 1Design – Solar energy utilization

Passive House Seminar for Professionals from the Building Sector Design – solar energy utilization and daylight Interior spaces with comfortable amounts of daylight adds to high quality of the passive house standard. The ratio of glassed and opaque surfaces has to be chosen carefully according to climatic conditions of the specific location. Daylight reducing factors have to be put in consideration. In southern regions effective shading is essential. In northern regions, the need of daylight has to be considered together with sprawl of glassed area, the risk of heat loss and necessity of high quality windows. Source: iEPDDAYLIGHT CORRECTLY ORIENTED WINDOWS COMFORTABLY ILLUMINATED ROOMS AVOIDING OVERHEATING INCREASED INTERIOR COMFORT Day 1Design – Solar energy utilization

Passive House Seminar for Professionals from the Building Sector Determinant Factors for Solar Energy Utilization The average amount of solar energy incidenting on respective building facade varies according to: To achieve maximum required solar heat gains, all of these aspects should be put into consideration already in the planning phase of a passive house. LOCATION LOCAL CLIMATE ORIENTATION SURROUNDING ENVIRONMENT FORM BUILDING FORM SHADING OBJECTS BUILDINGS VEGETATION OTHER WINDOWS OTHER THAN VERTICAL ROOF SHAPE AND ANGLE

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector It is necessary to place the passive house correctly within the landscape to avoid mistakes that could reduce solar heat gains of the building. Avoid shady places like dark valleys, northern slopes, the north side of dense forests, or places overshadowed by tall buildings. Also avoid locations with extreme windy conditions. Source: Location within the Landscape Finding an optimum site for the building

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector Climatic conditions vary with changing location and altitude. When designing a passive house - work with specific climatic data of the building site location. These have to also be used in the PHPP calculation and the design optimizing process. There might be locations where also microclimatic conditions should be considered. Source: Climate Average intensity of solar radiation in December, Slovakia Average daily temperatures in December, Slovakia

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector The EAST orientation gets the most of the sun in the morning, when, especially in winter, sun with low angle has also low intensity of solar radiance. The WEST oriented windows gets the most of the sun in the afternoon, when, especially in the summer, sun angle is low again, but the solar radiance is still too high, causing overheating and requiring usage of active shading systems. Building orientation should be utilized to the maximum by using SOUTH oriented facades with glazed areas and effective shading (to avoid overheating during summer months). The NORTH oriented windows have no significant benefit concerning solar gains, on the contrary, it may be the source of serious heat loss. Source: FA STU Solar Energy, Local Climate and Orientation

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector The sun angle should be analyzed for at every individual location. Its direction changes constantly throughout the year and throughout the day. Sun angle geometry and building orientation have to be included into passive house calculations and design processes (e.g. in PHPP). Sunray Geometry Spherical projection of the sun path for: N48°9´, E17°7´ (Bratislava, Slovakia) Date: January 1th Time: 16:00 Source:

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector Sunray Geometry – Summer α High intensity of solar radiation on south oriented facade with large glazed surfaces may cause overheating in the summer. This can be prevented by installing:  permanent overhang structures to block the direct sun (roof, balcony, etc). To achieve effectiveness, these have to respond to the sun angle geometry.  active shading systems (external blinds, shutters, shading panels, etc) for blocking of the direct sunlight and the light reflected from exterior surfaces.  Deciduous vegetation (provides shade in the summer, but not in the winter). Source: iEPD Summer sun angle: Bratislava, Slovakia α=65,5° Passive and active shading

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector α Sunray Geometry – Winter Source: iEPD Low winter sunlight can penetrate deep into the building and heat up surfaces (accumulation). The radiant heat transfer does not directly affect the indoor air temperature, but it reheats the surrounding surfaces (e.g. floor, walls, furniture, etc), which then indirectly heat the air. Solar heat gains can be utilized by:  accumulation in massive parts of the building during the day  heat release over night This helps to minimize the indoor temperature amplitude throughout the day and to improve the indoor thermal comfort. Also, together with internal heat gains, it lowers the annual heat demand. Heat release during the night Winter sun angle: Bratislava, Slovakia, α=18,5° HEAT ACCUMULATION HEAT RELEASE

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector During a sunny spring/autumn season, passive solar heat gain may contribute significantly to indoor thermal comfort. However, in certain regions shading may be necessary during some hours of the day. α Sunray Geometry – Autumn / Spring Season Source: iEPD Equinox sun angle: Bratislava, Slovakia α=42° While in standard house heating is necessary, passive house uses passive solar gains which are sufficient for indoor thermal comfort. This is determined by the local climate.

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector There are several factors reducing the amount of daylight entering the building which should be taken in consideration when designing a passive house:  Triple glazing  Window Reveal Depth  Glass with Heat Mirror (if applicable) See also European and national standards for daylight in buildings. Daylight Source: iEPD

Day 1Design – Solar energy utilization Passive House Seminar for Professionals from the Building Sector Daylight – Window Reveal Depth Source: iEPD A thick layer of thermal insulation of the passive house causes deeper window reveal, which may effect the amount of daylight entering the building. To reduce this effect (especially in massive constructions or retrofittings) the window reveal can be slanted and adapted to the sun angle.