Energy and environment in architecture book summary

1. Energy and
Environment
in
Architecture
AMIRA SAEED

2. What is a very low energy building?
Chapter 1
Annual energy costs in 92 individual office buildings (figure 1.1)
- Building no. 92 on the graph, with efficient and well-controlled
plant, will have an annual energy cost less than £3.0/m2yr.
On the other hand, an air-conditioned, deep-plan, overglazed
building, with poor services design and control, could cost more
than £45.00/m2yr.
Result in a saving of energy consumption of 70 to 90% compared to
the existing building stock.
- Nearly half of the UK’s energy use is accounted for
in buildings, and of this about a third is used in non-
domestic buildings (Figure 1.2)
Total final consumption 149.0 million tonnes of oil on 2016
(Figure 1.3)
1991
Figure 1.2

3. What is the factors upon which the energy performance depends?
Chapter 2
Building, system and occupant factors affecting energy
consumption in non-domestic buildings.(figure 2.1)
-1 building design.
-2 services design and performance (systems).
-3 occupant behaviour .
A fourth factor could be the presence of a particular activity or
process in the building, such as the use of a large computer in
Figure (2.2)
energyconsumption

4. Metabolism
3-1 what is going with food ?!!
Chapter 3
Food is converted into work and heat.
Figure (3.1)
Thermal balance between heat gains due to the
metabolism of the body and heat losses from the body
to the environment.
Heat losses from the body to the environment.
(Figure 3.2)
Parameters controlling
The environmental parameters controlling
(Figure 3.3)
Out door
thermal
comfort .

5. 3-2 How to reconcile between air quality and energy conservation ?
Chapter 3
Radiant heat loss and cold down-draughts can cause
thermal discomfort .
Figure (3.4)
Continuous glazing provides no opportunity to avoid direct sun in the
perimeter zone. Intermittent glazing results in patches of shade.
Figure (3.5)
ventilation chimneys, cupolas and grilles
became part of the architectural vocabulary,
(Figure 3.6)
This section explain the ventilation inside the chimney
(figure3.7)

6. 3-3 Visual comfort
Chapter 3
Comfort means ensuring that people have enough light
has the right quality and balance ,and people have
good views Figure (3.8)
Both daylighting and artificial lighting should be designed with recognition
of the tasks to be carried out in the space.,
(Figure 3.9)

7. 3-5 Adaptive opportunity and control ?
Chapter 3
Proprietary window system with glass panel to reflect traffic
noise away from ventilation opening
Figure (3.13)
Provision of both acoustic absorbent surfaces and exposed thermal mass.
Figure (3.11)
The influence of window design on noise
transmission when open.
Figure (3.12)

8. - When is the thermal balance point reached?
Chapter 4
Delivered energy use for naturally ventilated and air-
conditioned offices in the UK.
Figure (4.2)
The thermal balance point the external temperature at which the heat losses from
the building equal the heat gains. The graph shows the net heating demand (kW)
plotted against external temperature °C. Figure (4.1)

9. 4-1 Solar gain gains and thermal math
Chapter 4
Solar Utilisation Factor showing fraction of useful solar gains
as a function of solar gains/loss ratio for medium-weight
office building. Figure (4.4)
Solar radiation absorbed generates heat which is then redistributed by
long-wave radiation, convection and conduction.
Figure (4.3)

10. 4-2 Thermal balance of glazing
Chapter 4
Annual heating requirements as a function of glazing ratio of
south façade, for houses in the UK. Figure
(4.6)
Cladding and roofspace solar collector used to pre-heat air for ventilation.
Figure (4.5)

11. 4-3 Orientation and overshadowing
Chapter 4
Annual heating requirements as a function of glazing ratio of
south façade, for houses in the UK
. Figure (4.8)
LT curves showing relation between heating and lighting energy as a
function of glazing ratio for a south-facing office in the UK
Figure (4.7)
4- 4 Insulation and cold bridges
Influence of Urban Horizon Angle on annual heating energy
for south-facing office (from LT Method).
. Figure (4.9)

12. 5-1 Cooling load reduction
Chapter 5
Cooling load component
Figure (5.1)
Densely occupied modern office with gains from lighting and
equipment.
. Figure (5.2)

13. Chapter 5
Simultaneous heating and cooling caused by window opening in a mixed
mode building.
Figure (5.3)
Shading by vegetation and the use of light-coloured
surfaces to reduce solar gains to the envelope.
Figure (5.5)
The sources of heat gains likely to cause overheating.
Figure (5.2)
5-2 Shading and orientation (reduction of solar gains)

14. 5-2 Shading and orientation (reduction of solar gains)
Chapter 5
The transmission of solar radiation beneath fixed overhangs
responds to solar elevation but does not synchronise well
with seasonal heat demand and the need for daylight. .
Figure (5.8)
Ventilated cavity with low-emissivity foil to provide
protection from solar gains.
Figure (5.6)
The performance of shading by Internal and external
louvres gains.
Figure (5.7)

15. 5-3 Reduction of other heat gains.
Chapter 5
Three classes of shading devices having different effects
on view and ventilation .
Figure (5.9)
._ Conductive gains will be reduced by
1- Insulation of the opaque envelope.
2- Double glazing or low-e glazing.

16. 5.4 Ventilation cooling .
Chapter 5
The potential for ventilation cooling in relation to internal
and external temperature.
Figure (5.10)
- Cases B and C are typical of many modern non-domestic buildings
in spring, summer and autumn in the UK.
- In hot conditions, Case D, where the ambient temperature is above
the upper limit of comfort, ventilation will cause heat gain and it
should be reduced to the minimum needed for fresh-air requirements.

17. 5.5 Thermal mass .
Chapter 5
The effect of the distribution of thermal mass.
Figure (5.11)
Classification of thermal mass: primary (direct radiation), secondary
(reflected, re-radiated and convective) and tertiary (convective only).
Figure (5.12)

18. 5.6 Night ventilation
Chapter 5
Increased thermal coupling by incorporating hollow floor elements
connected to the interior by ducts (the Termodeck system).
Figure (5.13)
Options for air-flow paths for night-time and daytime ventilation.
Figure (5.14)

19. 6.1 Daylight as energy
Chapter 6
A well-daylit working environment not only saves energy but is also
preferred by the occupants.
Figure (6.1)
Variation of Daylight Factor (DF) in a side-lit room for glazing
ratios (glazing to external wall area) of 30% and 65%. DF
averaged across breadth of room.
Figure (6.2)
6.2 Daylight factor

20. 6.3 The sky as a light source
Chapter 6
Availability of daylight for southern UK. Example shows how from
a required minimum illuminance and DF, the fraction of daylight
sufficiency over the working year can be evaluated
Figure (6.3)
6.4 Interaction of shading with daylighting
Shading is an almost essential part of passive
building design. Its use has three purposes:
1- to reduce the solar heat gain to the room.
2-to prevent sunlight from falling onto occupants
3-to reduce glare.

21. 6.5 Lighting control systems
- Classification of shading elements
Chapter 6
Type BType A2Type A1
Fixed grids and fixed non-
reflective louvres, fritted, tinted
and reflective glass.
Light shelves, fixed reflective
louvres, overhangs (with ground
reflection), prismatic glass,
holographic film.
Movable blinds and louvres
with variable transmission .

22. 6.6 Daylighting and thermal function of glazing
Chapter 6
Advanced daylighting devices, such as reflecting louvres and
prismatic glass, redirect light to the back of the room, thereby
reducing the demand for supplementary artificial lighting.
Figure (6.4)
The energy balance at the glazed envelope of a building.
Figure (6.5)
Decision chart for choosing a lighting control strategy for the most cost-effective energy savings.
Figure (6.6)

23. 7.1 Ventilation regimes
Chapter 7
This section explain the ventilation inside the chimney
(figure3.7)
- Three regimes of ventilation can be identified ..
Minimum
ventilation .
Space
cooling .
Air
movement

24. 7.2 Natural ventilation
Chapter 7
- Wind pressure - Thermal buoyancy
Thermal buoyancy leads to vertical pressure
differences which drive ‘stack effect’ ventilation if the
envelope is permeable .
Figure (7.3)
Distribution of wind-induced pressure over the surface
of a building, in plan.
Figure (7.1)
Distribution of wind-induced pressure over the surface
of a building, in section.
Figure (7.2)

25. 7.3 Ventilation configurations
Chapter 7
single opening, and it is slightly improved due to the
increased probability of pressure differences occurring
between the two apertures. Effective ventilation depth
could be up to 9m, or three times floor to ceiling
height.
Figure (7.5)
The magnitude of the stack effect is dependent upon the
average temperature increment over the full height of the
chimney. Heating up the air as it leaves will have little effect.
Heating from solar gain (or other source) should take place
as low down as possible.
Figure (7.4)
Useful depth of single sided ventilation from double
openings for h>=0.5H.
Figure (7.6)
Cross-ventilation is very effective for wind-generated
pressure differences with useful depth up to 9m, or at
least three times floor to ceiling height.
Figure (7.7)

26. 7.4 Use of stacks and ducts
Chapter 7
Extract ventilation via a stack driven by wind suction and/or
thermal buoyancy
Figure (7.8)
The Ionica building in Cambridge uses large ventilator
elements located on the roof to ventilate internal spaces
via an atrium acting as an extract plenum or chimney. .
Figure (7.9)

27. 7.5 Mechanical ventilation
Chapter 7
Duct or underfloor fresh-air supply to avoid
double-banking.
Figure (7.10)
Cross-ventilation is very effective for wind-
generated pressure differences with useful
depth up to 9m,
Figure (7.11)
Traditional ventilation tower or badger in Iran.
Figure (7.12)

28. 7.6 Air-conditioning
Chapter 7
Fan-coil units for heating, cooling and fresh-air supply
Figure (7.13)
Consider the amount of space that the air-conditioning plant will take up
shows two actual buildings, one is air-conditioned, the other is not. In the same height,
the air-conditioned building has four floors, the naturally ventilated building has five floors.
Figure (7.14)

29. 8.1 The passive zone concept
Chapter 8
The passive zone depth is twice the floor to ceiling height for an unobstructed façade, but
is reduced by an atrium .
Figure (8.1)

30. Atria and sunspaces
Chapter 9
The environmental benefits of an atrium compared with an open court.
Figure (9.1)

31. 9.1 Daylighting and atria
Chapter 9
The ratio of external glazing to the protected area (or separating wall) has a strong
influence on the thermal performance of the atrium.
Figure (9.5)
9.2 Winter performance
Seasonal variation of shading and ventilation of an atrium. A change of DF from
20% to 4% allows sufficient light in winter and reduces solar gain significantly in
summer.
Figure (9.2)
Effect of atrium height on zone with the sky.
Figure (9.3)
Reflected light plays a vital role as well as direct sky light when the atrium
is intended to be a source of daylight
Figure (9.4)

32. 9.3 Summer performance
Chapter 9
Predicted monthly temperatures for a typical atrium of type C
Figure (9.6)
9.4 Heating in atria
Mixing ventilation from a high-level opening in an atrium
minimises stratification Figure (9.8)
Heating energy consumption by a building
with an atrium for different ventilation modes
Figure (9.7)
Displacement ventilation by low-level and high-level
openings encourages stratification which may be useful in
summer to keep warm air away from occupied floors.
Figure (9.9)

33. Chapter 9
The effect of ventilation openings and shading on average atrium
temperature.
Figure (9.10)
9.4 Heating in atria
The use of reflecting surfaces to direct
sunlight to the occupied zone of the atrium.
Figure (9.11)
If heating has to be provided in an atrium it should not be a
convective input, i.e. warm air. It should be limited to where
the occupants are, e.g. underfloor heating or a local
radiant source
Figure (9.12)

34. Chapter 10
The choice of energy source for environmental systems has a considerable
influence on cost. It also has a significant impact on environmental
pollution, in particular CO2 as shown in Table 10.1
10-1 Energy sources
A heat pump and the definition of Coefficient of
Performance (CoP). Typical values of CoP for building
applications are 2.0–4.5.
Figure (10.1)
10-2 Renewable sources of heat

35. Chapter 10
10-3 Electricity generation
Sankey diagram of combined heat and power (CHP)
system compared with conventional energy supply.
Figure (10.3)
10-4 Heat production and distribution
Boiler efficiencies as a function of boiler load .
Figure (10.4 )

36. Chapter 10
10-5 Heat emitters
Sankey diagram of combined heat and power (CHP)
system compared with conventional energy supply.
Figure (10.3)
10-6 Heat recovery
A heat pump and the definition of Coefficient of
Performance (CoP). Typical values of CoP for building
applications are 2.0–4.5.
Figure (10.1)

37. Chapter 10
10-7 Controls
Manual controls must be user friendly
to use them. The following points should be
considered
- lightning
- Heating
10-8 Management issues
Human factors have a high degree of influence on the actual energy use
of a building (see Figure 2.1). These factors are not directly within the
designer’s control; however, the ‘feel’ of the building has an impact on
how well its occupants respond to the designer’s intentions, and thus
contribute to its overall energy efficiency

38. 2 The LT Method

39. Chapter 11
11-1 Technical background
Northern and southern UK climatic zones for LT curves
Figure (11.2)
Energy flows in the LT mode the energy flows associated with inputs for
heating, cooling, ventilation and lighting, and ambient energy flows due to
fabric and ventilation heat losses, solar gains and useful daylight, as
illustrated in Figure (11.1).
11_2 Limitations of the LT Method

40. Chapter 12
How to use the LT Method
For the elevations (and the roof plan if glazed) propose a
glazing ratio. This is defined as the ratio of the glazed area
to the
total area of the façade. This need not be precise and could
be estimated using Figure 12.3 as a guide .
On the plan of the building, identify the side-lit passive
zones as in Figure 12.1, including the top floor The
passive zone .
12-2 Step 2: the glazing ratio12-1 Step 1: the passive zone
Passive and non-passive zones in plan and section .
Figure (12.1)
12.2 Passive and non-passive zones in
L-shaped plan 12.3 Definition of glazing ratio

41. Chapter 12
The passive and non-passive zone areas, and the specific
energy consumptions read from the LT curves, are entered
into the LT worksheet (12.5)
The vertical axis represents the annual primary energy
consumption in MWh/m2 , and the horizontal axis is the
glazing area as a percentage of total façade area .
12-4 Step 4: The LT worksheet12-3 Step 3: the LT curves
Example LT curve for office in southern UK
Figure (12.4)
The LT worksheet
Figure (12.5)
Rules for rooflights
Figure (12.6)

42. Chapter 12
certain fuels produce more CO2 than others, for the same
primary energy value. For example, coal produces more
CO2 than gas, for a given amount of primary energy, due to
its high carbon content .
12-6 Interpretation of cooling energy12-5 Primary energy and CO2
CO2 production for different types of fuel
Figure (12.6)
Example LT curve for office in southern UK
Figure (12.5)

43. Chapter 12
12-8 Atria and sunspaces12-7 The Urban Horizon Factor
The definition of Urban Horizon Angle (UHA)—the average
elevation of the skyline from the centre of the façade being
considered
Figure (12.6)
Reduced passive-zone depth for buffer-adjacent zone
Figure (12.8)
Buffer-space Thermal Savings (BTS) table for southern UK
Limit of obstruction-forming horizon in plan for UHF
Figure (12.7)

44. Chapter 13
13-1 Five-storey office building
- Passive zones
shows the building on an urban site, with dimensions and the
areas of the zones indicated. In designating the 6m passive zones
at outside corners the best performer for light and heat is
assumed, i.e. south rather than west or east. Note that the inside
corner is designated a non-passive zone.
- The LT curves
First the building type has to be selected. It is obviously type C,
and from the brief we assume the ‘low’ internal gains of 15W/ m2
and the 300 lux lighting datum.
- The Urban Horizon Angle
From the site plan (by making a sketch section) we have deduced
that the UHA from the centre of the third storey is less than 15° for
south and west, between 15° and 45° for north, and greater than
45° for east
Worked example of five-storey office building
Figure (13.1)

45. Chapter 13
13-2 School with conservatory
- In this example an early design objective is to create a ‘solar’
design with an unheated single-glazed conservatory running along
the south side acting as both a main circulation route and a
sunspace to provide pre-heated ventilation .
- The conservatory has clear glazing with movable shading giving
a buffer-adjacent zone depth of 4.5m. This, with a passive zone
depth of 6m from the north .
- total savings of 14.8MWh/y for the 44m separating wall, after an
occupancy correction factor of 0.55 has been applied.
Worked example of school with conservatory.
Figure (13.2)

46. Chapter 14
13-1 LT data and worksheet
Table 12.1 Table 12.2

47. Resources
- https://www.isover.com/what-very-low-energy-building
- [PDF]DIGEST OF UNITED KINGDOM ENERGY STATISTICS 2017