Transcript Passive solar systems for building renovation

ERASMUS IP Sustainable Refurbishment, Retrofit, Energy
Management in Housing
Passive solar systems for building
renovation
Maria Isabel Abreu
[email protected]
19th 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
There are some passive
solutions that are possible
to apply
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
Key passive solar building design concepts
Direct solar gain
Indirect solar gain
South facing glass
Isolated solar gain
Thermal mass to absorb, store, and distribute heat
Insulation and glazing
Passive cooling
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
Direct solar gain
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/Heat storage
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
Indirect solar gain
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/Heat storage
Thermal storage walls – Trombe walls
Isolated solar gain
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
Sunrooms
Convective loop through an air collector to a
storage system inside the building
Isolated solar gain
Sunrooms
Convective loop through an air collector to a storage system inside the building
Sunrooms
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
Insulation
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 lowertemperature body
Special glazing systems
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
Passive cooling
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
Preventing heat from entering the interior
(heat gain prevention)
Removing heat from the building
(natural cooling).
Passive 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
Window coverings
Window coverings are material used to cover a window to manage sunlight
Curtains / Drapes
Window blinds
Venetian blinds: Wood, Faux Wood, Vinyl, Aluminum
Mini blinds
Shutters
Window Shades, including:
Roman & Folding Shades
Roller Shades
Solar screen
Window coverings
Passive cooling
A solar chimney or thermal chimney
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
Passive cooling
Sunrooms can also be designed to perform this function
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 solar lighting
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
The use of reflecting surfaces to
admit daylight into the interior of a
building
Window sections should be
adequately sized, and to avoid overillumination 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
Renovation
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
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 reroofing.
Design additions to allow passive solar
access and facilitate movement of
passive heat gains to other parts of the
house
Renovation
Use high performance windows
and glazing for all new windows
and doors
Replace poorly performing
windows where possible
Relocate poorly orientated or oversized
windows and increase the size of solar
exposed south windows
Implement dark external floor finishes
And more…
Double glaze windows to reduce winter
heat loss
Create airlocks at
entrances in cool and
cold climates
Renovation
Seal existing windows and external
doors, and replace warped or poorly
fitted doors
Reorientate as much of the living
space as possible to the south side
South-facing bedrooms can
become living rooms
Add doors and walls to
create zones with similar
heating needs
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