This document discusses design recommendations for buildings in cold and cloudy regions. It recommends compact building designs with small surface area to volume ratios to minimize heat loss. It also recommends maximizing southern exposure for windows to encourage solar heat gain during winter. Specific building elements like roofs, walls and fenestrations should be insulated and use materials with high thermal mass and capacity to absorb solar heat. Passive solar heating strategies like Trombe walls and sunspaces can be used to effectively collect, store and distribute solar heat within buildings during winter.

1. Climatology for built environment
Submitted to:-
Divya mam
Submitted by:-
Md Mahmood.
12011bb006
Fsp III sem
Jnafau/Spa

2. COLD AND CLOUDY REGION
 These regions experience very cold winters, hence, trapping
and using the sun’s heat whenever it is available, is of prime
concern in building design. The internal heat should not be
lost back to the ambient.
 The insulation of building elements and control of infiltration
help in retaining the heat. Exposure to cold winds should also
be minimized.
 The main objectives while designing buildings in these zones
are:
 (A) Resist heat loss by:
 (a) Decreasing the exposed surface area
 (b) Increasing the thermal resistance
 (c) Increasing the thermal capacity
 (d) Increasing the buffer spaces
 (e) Decreasing the air exchange rate

3.  (B) promote heat gain by:
 (a) Avoiding excessive shading
 (b) Utilising the heat from appliances
 (c) Trapping the heat of the sun.
 The general recommendations for regions with a cold and
cloudy, or cold and sunny climate are given
 below.
 (1) SITE
 (a) Landform: In cold climates, heat gain is desirable. Hence,
buildings should be located on the south slope of a hill or
mountain for better access to solar radiation .

4. At the same time, the exposure to cold winds can be
minimised by locating the building on the leeward side.
Parts of the site which offer natural wind barrier can be
chosen for constructing a building.

5.  (b) Open spaces and built forms: Buildings in cold climates
should be clustered together to minimise exposure to cold
winds .
 Open spaces must be such that they allow maximum south
sun.
 They should be treated with a hard and reflective surface so
that they reflect solar radiation onto the building .
 (C)Street width and orientation: In cold climates, the street
orientation should be east-west to allow for maximum south
sun to enter the building.
 The street should be wide enough to ensure that the
buildings on one side do not shade those on the other side
(i.e. solar access should be ensured).

6. (2) Orientation and planform :-
 In the cold zones, the buildings must be compact with small
S/V ratios .
 This is because the lesser the surface area, the lower is the
heat loss from the building.
 Windows should preferably face south to encourage direct
gain.
 The north side of the building should be well-insulated.
Living areas can be located on the southern side while utility
areas such as stores can be on the northern side.
 Air-lock lobbies at the entrance and exit points of the
building reduce heat loss.
 The heat generated by appliances in rooms such as kitchens
may be recycled to heat the other parts of the building.

8.  (3) Building envelope :-
 (a) Roof: False ceilings are a regular roof feature of houses in
cold climates.
 One can also use internal insulation such as polyurethane
foam (PUF), thermocol, wood wool, etc.
 An aluminium foil is generally used between the insulation
layer and the roof to reduce heat loss to the exterior.
 A sufficiently sloping roof enables quick drainage of rain
water and snow.

9. A solar air collector can be incorporated on the south facing
slope of the roof and hot air from it can be used for space
heating purposes.
Skylights on the roofs admit heat as well as light in winters .
The skylights can be provided with shutters to avoid over
heating in summers.

10.  (b) Walls: Walls should be of low U-value to resist heat loss.
 The south-facing walls (exposed to solar radiation) could be
of high thermal capacity (such as Trombe wall) to store day
time heat for later use. The walls should also be insulated.
 The insulation should have sufficient vapour barrier (such as
two coats of bitumen, 300 to 600 gauge polyethylene sheet
or aluminium foil) on the warm side to avoid condensation.
 Hollow and lightweight concrete blocks are also quite
suitable . On the windward or north side, a cavity wall type of
construction may be adopted.

11. (c) Fenestration: It is advisable to have the maximum
window area on the southern side of the building
to facilitate direct heat gain.
 They should be sealed and preferably double
glazed.
 Double glazing helps to avoid heat losses during
winter nights. However, care should be taken to
prevent condensation in the air space between the
panes.
 Movable shades should be provided to prevent
overheating in summers.
(d)Colour and texture: The external surfaces of the
walls should be dark in colour for high absorptivity
to facilitate heat gains.

12. I. Maximizing Heat Collection in the Winter by
means of a thermal mass.
◦ Direct Solar Gain
◦ Trombe Wall – indirect solar gain
◦ Sunspace – combines both direct and indirect
solar gain
II. Minimizing Heat Loss in the Winter
III. Preventing Overheating in the Summer

13.  A Trombe wall is a system for indirect solar heat
gain and, although not extremely common, is a
good example of thermal mass, solar gain, and
glazing properties used together to achieve human
comfort goals passively
 It consists of a dark colored wall of high thermal
mass facing the sun, with glazing spaced in front
to leave a small air space. The glazing traps solar
radiation like a small greenhouse. An attached
sunspace is essentially a Trombe wall where the air
space is so big it is habitable.

14. A Trombe wall (left) and attached sunspace (right).

15.  Trombe walls are a very useful passive heating
system. They require little or no effort to operate,
and are ideal for spaces where silence and privacy
are desirable. Sunspaces are equally simple and
silent, and can allow views. Rooms heated by a
Trombe wall or sunspace often feel more
comfortable than those heated by forced-air
systems, even at lower air temperatures, because
of the radiantly warm surface of the wall.
 A successful Trombe wall or attached sunspace
optimizes heat gain and minimizes heat loss
during cold times, and avoids excess heat gain in
hot times.

16. A vented Trombe wall heats air
convectively as well as heating the space
radiatively.
Vents can be shut at night to keep the
convection loop moving the right direction.

17. Using low-E glazing can prevent heat from re-radiating
out through the glass of a Trombe
wall and greatly reduce the amount of heat lost.
Applying a spectrally selective surface or low-E
coating to the wall itself can also improve
performance by reducing the amount of
infrared energy radiated towards the glass.
Low-E glazing reflecting heat back into the Trombe wall
A Trombe wall with overhang to shade from summer sun

18. A sunspace with vents for convective heating as well as radiative
heating
The same sunspace at night, with vents closed, to keep convection
going the proper direction