erasmus ip sustainable refurbishment, retrofit, energy management in housing passive solar systems...
TRANSCRIPT
ERASMUS IP Sustainable Refurbishment, Retrofit, Energy Management in Housing
Passive solar systems for building renovation
Maria Isabel [email protected] May, Corte
In passive solar building design, windows, walls, and floors are made
to collect, store, and distribute solar energy in the form of heat in the
winter and reject solar heat in the summer
This is called passive solar design because, unlike active solar systems,
it doesn't involve the use of mechanical and electrical devices.
The key to designing a passive solar building is to best take advantage of the local climate
These technologies:
- convert sunlight into usable heat (water, air, thermal mass)- cause air-movement for ventilating- protect from sunlight
with little use of other energy sources
Passive heating use
Passive cooling use (reduce summer cooling requirements)
INTEGRATION PASSIVE SOLAR SOLUTIONS IN BUILDING RENOVATION
It is recognized that the construction technologies for renovation are relatively new and, unfortunately, most R&D and products
development is directed toward new construction
With the propose of reaching similar energy performance requirements as those established for new buildings, it is possible to adopt in existent buildings a range of passive energy-renovation-solutions
There are some passive solutions that are possible to apply
Key passive solar building design concepts
Direct solar gain
South facing glass
Thermal mass to absorb, store, and distribute heat
Insulation and glazing
Indirect solar gain
Passive cooling
Isolated solar gain
Direct gain, indirect gain and isolated gain/Thermal mass
The goal of all passive solar heating systems is to capture the sun’s heat within the building’s elements and release that heat during periods when the sun is not shining
At the same time that the building’s elements (or materials) is absorbing heat for later use, solar heat is available for keeping the space comfortable
The actual living space is a solar collector, heat absorber and distribution system
South facing glass admits solar energy into the house where it strikes directly and indirectly thermal mass materials such as masonry floors and walls
The direct gain system will use 60–75% of the sun’s energy striking the windows
Direct solar gain
The ratio of solar exposed glass to exposed thermal mass in a room is critical and varies significantly between climates and designs
Too much thermal mass for the available solar heat input creates a heat sink and increases auxiliary heating needs.
Insufficient thermal mass causes daytime overheating and rapid heat loss at night
Use 6 to 9 m2 of living space floor area for each 1 m2 of south glazing area
Direct solar gain/Heat storage
Thermal mass is located between the sun and the living space
The thermal mass absorbs the sunlight that strikes it and transfers it to the living space by conduction and convection
The indirect gain system will use 30–45% of the sun’s energy striking the glass near the thermal mass wall
Efficiency can suffer from slow response (thermal lag) and heat losses at night
Indirect solar gain
Thermal storage walls – Trombe walls
Indirect solar gain/Heat storage
Have its integral parts separate from the main living space
The system use solar energy to passively move heat from or to the living space using a fluid, such as water or air by natural convection or forced convection
The isolated gain system will use 15–30% of the sunlight striking the glazing toward heating the adjoining living areas
Isolated solar gain
SunroomsConvective loop through an air collector to a storage system inside the building
SunroomsConvective loop through an air collector to a storage system inside the building
Isolated solar gain
Use a dark color for the thermal wall
The thickness of the thermal wall should be 20-30 cm for adobe or earth materials, 25-35 cm for brick, 30-45 cm for (dense) concrete
For a sunroom with a masonry thermal wall, use 0.30 m2 of south glazing for each m2 of living space floor area
Have a ventilation system for summer months
If overhead glass is used in a sunroom, use heat reflecting glass and or shading systems in the overhead areas
Sunrooms
Thermal insulation is the reduction of heat transfer between objects in thermal contact or in range of radiative influence
Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials
Thermal insulation provides a region of insulation in which thermal conduction is reduced or thermal radiation is reflected rather than absorbed by the lower-temperature body
Insulation
Insulated glazing more commonly known as double glazing (or double-pane, and increasingly triple glazing/pane)
are double or triple glass window panes separated by an air or other gas filled space to heat transfer across a part of the building envelope
Special glazing systems
Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort
Passive cooling
Preventing heat from entering the interior (heat gain prevention)
Removing heat from the building (natural cooling).
Solar control
A properly designed shading system can effectively contribute to minimizing the solar heat gains
Shading both transparent and opaque surfaces of the building envelope will minimize the amount of solar radiation that induces overheating in both indoor spaces and building’s structure
The heat gain captured through the windows and envelope will be reduced
Passive cooling
Window coverings are material used to cover a window to manage sunlight
Curtains / Drapes
Window blindsVenetian blinds: Wood, Faux Wood, Vinyl, AluminumMini blinds
ShuttersWindow Shades, including:
Roman & Folding ShadesRoller Shades
Solar screen
Window coverings
Window coverings
A solar chimney or thermal chimney
Passive cooling
Is a way of improving the natural ventilation of buildings by using convection of air heated by passive solar energy
A simple description of a solar chimney is that of a vertical shaft using solar energy to enhance the natural stack ventilation through a building
With the connecting lower vents to the living space open along with windows on the north side, air is drawn through the living space to be exhausted through the sunroom upper vents
Passive cooling
Sunrooms can also be designed to perform this function
Passive solar lighting techniques enhance taking advantage of natural illumination for interiors, and so reduce reliance on artificial lighting systems
This can be achieved by careful building design, orientation, and placement of window sections to collect light
Passive solar lighting
The use of reflecting surfaces to admit daylight into the interior of a building
Window sections should be adequately sized, and to avoid over-illumination can be shielded with a brise soleil, awnings, well placed trees, glass coatings, and other passive devices
Opportunities for improving or adding passive solar design features when renovating an existing building
Existing brick walls often have adequate thermal
mass
Insulate external walls, ensure that thermal mass is balanced by
increased solar access, and design openings and convective
flow paths to ensure that additional solar gains are
distributed effectively
Renovation
Relocate poorly orientated or oversized windows and increase the size of solar exposed south
windows
Use high performance windows and glazing for all
new windows and doors Replace poorly performing windows where possible
Increase existing insulation levels and insulate any previously uninsulated ceilings and walls (and floors in cool climates) while they are exposed or during re-cladding or re-roofing.
Design additions to allow passive solar access and facilitate movement of passive heat gains to other parts of the house
Renovation
Implement dark external floor finishes
Double glaze windows to reduce winter heat loss
RenovationCreate airlocks at entrances in cool and cold climates
Add doors and walls to create zones with
similar heating needs
Reorientate as much of the living space as possible to
the south side South-facing bedrooms can
become living rooms
Seal existing windows and external doors, and replace
warped or poorly fitted doors
And more…
Consider adding a sunroom to maximize solar gains in cool climates
Solar passive solutions compatible with existent and historic buildings architecture
Direct solar gains
In summer is possible to use internal movable
insulation, ensuring air circulation between this device and the window
Solar passive solutions compatible with existent and historic buildings architecture
Thermal mass wall behind a window (Trombe wall)
The integration is possible in existing
windows or doors that are not usually opened,
preserving existing materials and outside
appearance
Solar passive solutions compatible with existent and historic buildings architecture
Attached sunspace
Solar passive solutions compatible with existent and historic buildings architecture
Convective loop
The thermosyphon effect transfers the heated air in the channel again to the indoor space by an
upper vent
During the night is necessary to insulate the windows and close the
openings
Thank You