potential for energy saving in building transition spaces

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Energy and Buildings 39 (2007) 815–822

Potential for energy saving in building transition spaces

Adrian Pitts *, Jasmi Bin Saleh

School of Architecture, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom

Abstract

This paper reports on an analytical investigation into the energy saving potential associated with modified comfort limits in transitional spaces

in buildings. Such spaces may not require the same high level and close environmental control of more fully occupied spaces and thus a wider

variation in conditions and interpretation of thermal comfort may be permitted. Estimations are made of energy saving potential based upon typical

floor area proportions utilised for transition spaces of various types in office/commercial buildings. The data are combined with suggested norms

for comfort expectation that have wider temperature limits than for normally occupied office zones. The method has been applied to a series of

building types situated in the climate of the East Pennines area of the UK using a thermal analysis tool. The results show that useful energy savings

(particularly for heating) are possible by allowing for a modest (and realistic) relaxation of prescribed comfort standards in transition spaces.

Further work is now required to confirm the limits and assess energy saving in practice.

# 2007 Elsevier B.V. All rights reserved.

Keywords: Thermal comfort; Transition spaces; Energy use; Heating; Cooling

1. Introduction

Transition spaces in buildings (including such areas as

foyers, lobbies, certain atria and ancillary spaces not directly

occupied in relation to the activity of the building) pose an

interesting and fruitful area for comfort research. Entrance and

transition areas of buildings are often perceived as some of the

most important in architectural design terms since they also

impact on a wide range of senses and perceptions of human

occupants; have an important role in control of circulation; and

are often associated with some of the longer lasting impressions

that occupants or visitors have of the building.

It is suggested in this paper that such spaces, whilst being

important, do not require the fine control of temperature or

comfort limits associated with the principal areas of a building;

and that they can also be actively designed to modify the

experience and expectation of persons moving through them.

Opportunities exist for such areas to be provided with

environmental conditions lying someway between internal

and external conditions. This may offer benefits such as

reduction of thermal shock for occupants moving into and out

of spaces as well as modifying comfort expectations.

* Corresponding author. Tel.: +44 114 222 0319; fax: +44 114 279 8276.

E-mail address: [email protected] (A. Pitts).

0378-7788/$ – see front matter # 2007 Elsevier B.V. All rights reserved.

doi:10.1016/j.enbuild.2007.02.006

An additional consideration is that such spaces are often

located at the perimeters of buildings; frequently have large

areas of glazing; and also experience significant air exchange

with the outside environment. As such they may generally

require considerably higher levels of building services

provision for comfort conditioning and consequently have

higher energy consumption. Some research has shown that

transitional spaces can help to save energy if they can be

developed according to their climatic needs [1].

2. Background

The inclusion of transitional spaces, in the form of corridors,

draught lobbies, atriums and stairwells, is unavoidable in the

design of most non-domestic buildings. A wide-ranging survey

of designed spaces carried out by the authors (but not yet

published) indicates the proportion of such areas may vary

between (a more typical) 10% to as high as 40% of the total

volume in different types of buildings. Such spaces are thus

important in many ways.

Transitional spaces are defined as spaces located in-between

outdoor and indoor environments acting as both buffer spaces

and physical links. Other than being functional as circulatory

routes for the building, the design of these spaces is considered

very important by architects for reasons of aesthetics and as

emergency exit routes in the event of fire. The importance of

optimum energy consumption in transitional spaces is also very

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http://dx.doi.org/10.1016/j.enbuild.2007.02.006

Table 1

The Fanger and comfort scale

Hot +3

Warm +2

Slightly warm +l

Neutral 0

Slightly cool �1

Cool �2

Cold �3

A. Pitts, J.B. Saleh / Energy and Buildings 39 (2007) 815–822816

relevant in non-domestic buildings, as these spaces do not

normally generate ‘income’ from the commercial activities

carried out, hence any wastage associated with higher energy

cost is economically difficult to justify.

Currently it is common to find that considerable amounts

of energy are required to sustain comfort levels for these

environments in line with various prescribed building

standards. The energy consumption may be comparable with

the energy use in all other occupied areas of the building taken

together in some extreme examples, and buildings that have

sizable circulatory spaces face higher operational costs. Indeed

some researchers have suggested that the energy consumption

in transitional spaces, per unit area or volume, may be as high

as three times that of the remainder of the inside of a building

[2,3].

This paper aims to investigate the impact of transitional

spaces and their influence on energy consumption in buildings

by means of a parametric study of variations in the layout and

orientation of the building and the transition spaces. Several

notional types of building layout that are commonly found have

been used for simple investigative modelling of energy

consumption. The calculations of energy use were initially

carried out for a base case building assuming temperatures in

the transitional spaces that conformed to the recognised

building environmental/comfort standards. These results are

then compared with varied internal temperatures; this range of

temperatures is based on a wider interpretation of what might

be considered acceptable for comfort. Some previous work has

already indicated that such potential might exist [4] and in this

paper the consequential effect on energy consumption is now

considered. This may lead to better understanding of how to

manage energy consumption in transitional spaces by making

adjustments and alterations or choosing alternatives to existing

design, as well as taking note of peoples’ sensation and

expectations.

In practice, the levels of energy consumption in buildings

and transitional spaces may differ from those anticipated at the

design stage, which are frequently based on assumption of

annual average thermal requirements of the building. The

investigation therefore also highlights the different levels of

energy consumption resulting from irreversible design deci-

sions made at the outset. These initial evaluations arising from

modelling of notional buildings and from evidence on energy

consumption may lead to development of a more holistic

energy analysis in the future and an associated cost-benefit

appraisal.

3. Review of comfort issues

Contemporary research on thermal comfort has been well

documented over a period of more than three decades, but most

research has been carried out in relation to human thermal

response to stable environmental conditions experienced over

sustained periods of time. However, the realities of building

design and building use by occupants have created a rather

more complex situation in practice. Fanger’s research in this

field, commencing over 30 years ago [5] led to the specification

of international standards for thermal comfort [6], which were

widely adopted. Further practical implementation has occurred

such as in ASHRAE Standard 55 [7]. A consequence of this is

that an approach to thermal comfort which is perhaps best

applied to well-controlled, mainly air-conditioned, buildings

might be used as a benchmark for thermal design of all space

types and across many parts of the world with varying climates.

Some application of adaptive approaches in less intensively

conditioned spaces is now included in the standards which is

beneficial, however more development is needed.

In his research, Fanger measured air temperature, mean

radiant temperature, relative humidity, and air speed together

with activity and clothing levels for groups of subjects situated

in controlled environmental chambers. At the same time the

subjects rated their comfort sensation on the scale shown in

Table 1. Correlations and analyses were then carried out that

resulted in the derivation of a comfort equation that predicted

the average sensation of a group of human occupants exposed to

a given set of circumstances and also predicted the number who

would be dissatisfied. The predicted mean vote (PMV) and

predicted percentage dissatisfied (PPD) are terms now

commonly used as a measure of the expected average response

from a large group of people to a specific experienced set of

environmental conditions. It must be recognised that the kinds

of environment in which the initial studies from which the

equations were developed (and many subsequent ‘laboratory’

studies), were somewhat different to the temporary and

transitional nature of building foyers and entrance/circulation

spaces. The limitations to use are normally clearly stated in the

various comfort standards, and transition spaces would

normally fall outside their remit; however it is still necessary

for building designers to make decisions about how to service

such spaces and in the absence of other information they are

likely to adopt the general approach of the standards. It is clear

that work is needed therefore to help define modified standards

and to examine the potential to influence energy use.

The PPD index provides a measure of the percentage of

people who will be dissatisfied in thermal comfort and this is

related mathematically to the PMV. Based on the analysis, there

is no condition where everyone is predicted to experience

comfort conditions, and there is an assumption that there will

always be a small proportion (at least 5%) of people who cannot

be satisfied. However expectation of comfort in a transition

space is rather different to expectation of conditions in a well

controlled air conditioned office and many other environments.

As the interaction of the occupant with the thermal environment

may be transitory; it might be suggested that wider than normal

A. Pitts, J.B. Saleh / Energy and Buildings 39 (2007) 815–822 817

variations in thermal conditions should be investigated.

Reviews of recent research reveal a relative lack of information

and investigation for occupant response to conditions in

transitional spaces. Such spaces increase the dimensions of

complexities in maintaining comfort levels and the time spent

in transit such as to give more variable results for what is a more

variable environment.

In the recent standards the expectation is that conditions will

be maintained within �0.5 for the PMV, representing a limit of

10% PPD. In fact several variations of limit exist depending on

space categorisation—this is discussed by Olesen et al. [8] in

relation to energy performance of buildings. The three

categories they refer to show PMV limits of �0.2 for category

A;�0.5 for category B; and�0.7 for category C environments,

which already indicates a willingness in some circumstances to

relax the PMV limits.

The research of a number of authors has also considered

methods that take into account human adaptability in various

environments and climates [9]. Such work is linked to transition

environments since research on adaptive approaches might also

be used to justify assumptions about how people using, or

passing through, transition spaces over relatively short periods

of time might react or adapt. It might also be inferred from the

existing comfort standards that occupants are willing to tolerate

wider ranges of comfort in certain situations; for example in the

ASHRAE Standard it is stated that in adaptive environments,

such as naturally conditioned spaces, an acceptability level as

low as 80% (PPD = 20%) can be used. Indeed there are a

number of circumstances in both main standards [6,7] when an

increase of PPD by 5 or 10% might be allowed for.

As a result of this information one can infer an opportunity for

transition spaces whereby a wider band of the normal PMV could

be acceptable. A variation to a larger PPD might also be used or

perhaps the mathematical relationship between PMV and PPD

could be revised for transition spaces. The approach to be taken in

this study is therefore to compare two bands of PMV variation:

�0.5 (for a limit of 10% PPD) and�1.0 (equivalent to a limit of

26% PPD). The variation is introduced through modification of

air temperature in the transition space. It seems obvious to

determine if such considerations are likely to produce significant

reductions in energy requirements, which is the purpose of the

work reported in this paper. The opportunity to improve the

energy performance of buildings may thus exist as well as the

opportunity to examine how entrance and circulation spaces in

buildings are designed. Internal thermal environments might be

conceived of as a series of sequential experiences for occupants

moderating their environment between exterior and interior

conditions. In this way both improved comfort as well as

optimised energy performance can be achieved.

4. Methodology

The method of investigation has been to examine variations

in temperatures in building spaces according to the foregoing

discussion together with variations in building design. Initially,

four different notional building types have been considered

(identified as A, B, C and D in this study)—in each case a single

floor level, of area 200 m2, has been investigated but with

different plan variations. These were selected to show options

often developed at the design stage that are based on a

building’s cost budget. Floor and ceiling/roof heat flows have

been excluded from the analysis since it is anticipated that in

practice multi-storey buildings would be designed and their

impact only relevant to the highest and lowest floors. In the four

types variations in orientation have also been included to assess

heat gains and losses. This approach to layout is part of the key

information often defined in design briefs and used by designers

a rule of thumb to develop a building design.

Type A has a linear foyer transition space along the shorter

facade of a rectangular plan building; the four principal

orientations (north, east, south and west) are considered for the

direction in which this foyer may face. In all orientations it is

the shorter facade that faces the specified direction. Type B has

its foyer area set into the middle portion of the longer facade of

a similar rectangular building; again four orientations (north,

east, south and west) are analysed for the longer transition space

containing facade. Type C has a circulation corridor set across

the shorter axis of the same rectangular floor area building with

two variations considered (east–west corridor and north–south

corridor; in each case the corridor runs across the shorter

width). A modification on type C was considered as a further

option in which the ‘corridor’ transition space ran parallel to the

longer axis of the building. This variation was discounted

however since it produced very similar results and was also felt

to be less likely to be found in practice due to the narrowness of

the corridor. Type D has external perimeter corridor running

around the outside of the building; two orientations are

considered with the main (longer) facades running either east–

west or north–south.

Diagrams of the basic layouts of each type are shown in

Figs. 1–4; in each case the transition zone is shown in position

relative to the overall floor plan; the orientation variations are

derived by rotating the whole building (not just moving the

location of the transition space). A further variation of enclosed

transition space as an ‘atrium’ type space was considered but

has not been analysed as the impact on building energy

consumption would require more details of the building height/

number of storeys to be included. The spaces identified in each

model are labelled as the normally occupied and usable ‘main’

space; and the associated ‘transition’ space for purpose of

differentiation in the diagrams.

5. Thermal analysis

Many tools are available for the thermal analysis of

buildings and the choice made in this study was to utilise an

option that was matched to needs without involving very

complex and detailed building data input. The buildings being

assessed are simple in form and function with the major

influences being those of internal heat gain and external climate

(particularly the sun). It was assessed as necessary to have some

inclusion of dynamic affects but not appropriate to use complex

full dynamic simulation (it not being clear that the additional

data input would yield any more accurate answer and with the

Fig. 1. Type A floor layout shown with transition space on south facade. Fig. 3. Type C floor layout shown with east–west transition space corridor.


negative effect of perhaps narrowing the range of applicability

of any conclusions drawn). The method chosen for investiga-

tion of energy flows and heating and cooling requirements was

a spreadsheet analysis using the admittance procedure based

upon techniques and data specified in the CIBSE Guide [10].

The implementation of the tool was one that had been

developed and tested extensively at the authors’ institution and

it has been used successfully in many practical evaluations of

building design proposals.

Regarding input data, the external temperatures and solar

radiation levels were taken from an example year of data

(hourly values) for the East Pennines area of the UK (this area is

typical of average national climate in the UK). The energy use

analysis was performed on monthly basis and the results

subsequently summed to provide yearly outputs of energy

requirements for heating and cooling.

A glazing ratio of 20% of wall area is assumed for the main

usable space, and 50% of the transitional space wall area. Wall

Fig. 2. Type B floor layout shown with transition space on south facade.

U values are set at 0.35 W m�2 8C�1; glazing U values are

2.2 W m�2 8C�1; the other main input parameters for use in the

model are shown in Table 2. Much of the input data are based on

standards set in the UK. Heat gains are incorporated from solar

sources (using the weather data for the site) and also from

occupants, lighting, and other electrical loads. The schedule of

occupancy and lighting and equipment use follows a traditional

daily pattern with reductions at shoulder periods, typical data is

shown in Table 3. The transitional space occupants are specified

to have different and varied behaviours compared to those in the

main usable space as they would be walking and standing (as

part of the process of entering, leaving or moving about the

building), compared to the sedentary behaviour normally found

in an office space. This is consistent with findings for an atrium

study of occupant comfort and behaviour in which the atrium

acted as a circulation zone [11].

The frequent opening of doors that connect to the outdoors

would allow greater air-change in the transitional space. Hence,

Fig. 4. Type D floor layout sown in east–west orientation with surrounding

corridor transition space.

Table 2

Building statistics: data for example single storey office

Building statistics Type A Type B Type C Type D

Total floor area (m2) 200 200 200 200

Building volume (m3) 600 600 600 600

Total gross walled area (m2) 180 180 180 180

Main occupied space floor area (m2) 180 180 180 144

Transitional space floor area (m2) 20 20 20 56

Main occupied space exposed facade area (m2) 138 165 168 0

Transitional space exposed facade area (m2) 42 15 12 180


in this investigation a higher air-change was used for the

transition zone (1 air-change per hour during unoccupied periods

and 2 air changes per hour during occupied hours) as compared to

the usable space at half an air change per hour (unoccupied) and

one (occupied). The affect of sophisticated controls have been

ignored. The figures have been chosen to be representative of

conditions to permit comparisons rather than being exact.

The variations in internal temperatures chosen for investiga-

tion were determined by consideration of the heat balance

equation and prediction of PMV. Values for PMV were

determined according to the algorithms specified by ASHRAE

and ISO organisations [6,7]. The main usable space was

assumed to have the following conditions which equate closely

to a PMV of 0.

� a

Ta

In

H

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

ir temperature = mean radiant temperature = 23 8C
� r elative humidity = 50%
� m
ean air velocity = 0.1 m s�1
� m
etabolic rate = 1.0 met
� c
lothing level = 1.0 clo
ble 3

ternal heat gain data

our No. of occupants Lights (W m�2) Equipment (W m�2)

Main Transition Main Transition Main Transition

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

1 1 5 5 5 5

10 2 8 10 10 10

20 4 8 10 10 10

20 4 8 10 10 10

20 4 8 10 10 10

10 4 8 10 10 10

10 4 8 10 10 10

20 4 8 10 10 10

20 4 8 10 10 10

20 4 8 10 10 10

10 2 8 10 10 10

1 1 5 5 5 5

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

For the transition space alternative values were chosen for

several parameters. Firstly the air movement was assumed to

be slightly higher at 0.3 m s�1; this is consistent with findings

from research for enclosed transition type spaces (for instance

0.27 m s�1 [12]). The metabolic rate was also assumed to be

slightly higher at 1.4 mets to account for movement (again

consistent with previous studies [4]); clothing level was

assumed to be unchanged as there is no reliable evidence to

suggest an alternative value. Under these conditions a PMVof 0

results when air temperature and mean radiant temperature are

both set at 21 8C, this transitional space temperature is used for

the base case analysis. As can be seen this is 2 8C lower than

required in the main occupied space and this immediately

offers scope for reducing heating energy consumption; the

effect of this is not analysed here however as the main concern

is with the variation from widening of PMV bands in the

transition zones.

In order to carry out the comparisons the temperature in the

transition space was varied from the value above in the thermal

analyses. The variations were calculated on the basis of

assuming air temperature to be the same as mean radiant

temperature and that the adjustment in these values would be

matched to the range of PMV that was defined for consideration

earlier in the paper. Air temperature and mean radiant

temperature adjusted to either 18 or 24 8C gives a range in

PMVof approximately �0.5; adjusting to 16 and 26 8C gives a

range in PMV of �1.0. Therefore for the energy analysis the

values for internal temperature in the transition spaces were

varied to take the following values: 16, 18, 21, 24, and 26 8C,

representing PMVs of �1.0, �0.5, 0, +0.5 and +1.0.

A range of thermal analyses were thus completed: four the

four main building/transition space type variations; for both

heating and cooling energy requirements (and for main and

transition space areas separately); for the variations in

orientation; and for the five different temperatures in each case.

6. Results presentation

The charts shown in Figs. 5–12 illustrate the findings of the

analysis—an attempt has been made to allow comparison of

the most important issues, therefore in each diagram the

energy use is shown as a bar in which the ‘main’ and

‘transition’ space energy use is differentiated by the shading.

Energy consumption is shown on the Y-axis and a variety of

information to differentiate the various cases is shown along

the X-axis.

Fig. 5. Annual heating energy use for type A layout (transition space tem-

peratures of 21, 18 and 16 8C for each orientation).

Fig. 6. Annual cooling energy use for type A layout (transition space tem-


Fig. 8. Annual cooling energy use for type B layout (transition space tem-


Fig. 9. Annual heating energy use for type C layout (transition space tem-



Along the X-axis the bars are grouped in sets of three and in

every case the first of the three bars represents the base case; the

second the relaxation to PMV �0.5; and the third bar PMV

�1.0. The title to each chart makes clear the internal

temperatures associated with the three bars: 21, 18 and

16 8C for the three heating alternatives; and 21, 24 and 26 8C

Fig. 7. Annual heating energy use for type B layout (transition space tem-


for the three cooling alternatives. Each grouping of three bars

indicates a different orientation for the transition space. As an

example of explanation, Fig. 5 shows the type A design

predicted heating energy use for the orientations of the

transition space (marked in order North, East, South and West)

and within each orientation there are three bars representing the

Fig. 10. Annual cooling energy use for type C layout (transition space

temperatures of 21, 24 and 26 8C for each orientation).

Fig. 11. Annual heating energy use for type D layout (transition space


Table 4

Percentage reduction in heating energy use (averaged for all orientations)

Transition space alone Effect on whole building


energy use for 21, 18 and 16 8C (sequentially) as the

temperature of the transition space.

7. Analysis

It should be understood at the outset that energy use in

buildings with significant or larger transition spaces is generally

higher than for buildings with smaller or less significant such

spaces; also that buildings without any such spaces (and which

are designed to be thermally efficient) can have the lowest

overall energy use of all. However transition spaces are an

inevitable element of modern buildings and methods for

optimal operation should be sought. Further, other roles might

be associated with transition spaces, such as modifying the

thermal expectation of people passing through them, and may

permit operation of other parts of buildings in more efficient

ways.

It is clear from the outset that the widening of the range of

temperatures used in the transition space analysis means that

the servicing systems are not required to operate at such high

intensity to produce comfortable conditions. As a result the

energy use is diminished; however it is important to be able to

gain some understanding in a more precise way. The charts

presented show reductions in energy use as the temperatures are

Fig. 12. Annual cooling energy use for type D layout (transition space


allowed to vary, though the reductions are more marked for

heating energy use than for cooling energy use. Tables of data

have been compiled to present the differences in energy use—

these are given as average values taking account of all

variations in orientation. The impact of different orientations

had some effect on cooling energy use due to increasing solar

gains (this can be seen most markedly in Fig. 6 for type A

layout), though there was only modest variation in heating

energy use with orientation.

Table 4 illustrates the energy use reductions predicted.

Savings of up to 35% of transition space heating are possible

(types A and D). Types B and C have less impact made by the

change in temperature, principally because the lower external

area of these types means their heat loss is already relatively

low. The impact on the whole building heating energy use is

lower for all types of layout but still quite significant with a

reduction of over 11% for type A and over 32% for type D (with

its total enclosure by the transition space).

Table 5 shows the averaged energy saving potential based on

cooling energy usage; reductions in all cases are in single

figures indicating less potential. Though the variations in

internal temperature are of a similar magnitude to the heating

situation, the energy flows into the space are dominated by solar

and internal gains.

An approach that could yield more advantageous reductions

in cooling energy use would be to omit the use of cooling

systems from the transition spaces entirely. Some compensation

for this lack of cooling could be gained if it was possible to

increase the ventilation rate through greater use of opening

windows and doors thus allowing the transition space to operate

in a more natural, free-running state during warm months. The

benefits of such an approach can be seen if overall energy use is

considered with cooling operating only in the main building

area—this is shown in Table 6. These data indicate significant

benefits of up to about 13% energy reduction when the main

building is surrounded by the transition space acting as a buffer.

18 8Ca 16 8Ca 18 8Ca 16 8Ca

Type A 22% 35.4% 7.1% 11.4%

Type B 19% 31.1% 2.6% 4.2%

Type C 18% 29.4% 4% 6.6%

Type D 22% 35.6% 20.2% 32.7%

a Transition space temperature.

Table 5

Percentage reduction in cooling energy use (averaged for all orientations)

Transition space alone Effect on whole building

24 8Ca 26 8Ca 24 8Ca 26 8Ca

Type A 4.5% 7.5% 1.3% 2.2%

Type B 3.2% 5.3% 0.5% 0.9%

Type C 2.8% 4.6% 0.4% 0.7%

Type D 5.1% 8.5% 3.7% 6.1%

a Transition space temperature.

Table 6

Summary of reductions in annual whole building energy use when cooling

systems used only in main part of building

Transition space lower temperature

18 8C 16 8C

Type A 1.5% 2.4%

Type B 0.5% 0.8%

Type C 0.4% 0.6%

Type D 8.3% 13.3%


8. Conclusions

This study has investigated energy saving potential if more

flexible approaches to defining comfort in transition spaces can

be accommodated in building design. This has been tested for

four basic building layouts. The results clearly show substantial

opportunity for heating energy saving which can be quantified

in the region of 7% for the building as a whole, if transition

space temperatures are allowed to reduce by 3 8C below that

required for a PMV of 0, and 11% if a 5 8C reduction is

permitted. The reductions in cooling energy use are rather

smaller though still potentially significant, with savings up to

about 2%.

In terms of layout and orientation a few conclusions may be

drawn by reference to Tables 4–6: firstly that those types of

transition space that extend over the widest proportion of the

facade of the building have the most impact and the greatest

potential to reduce energy use. This can be seen by the results of

types A and D layout. Secondly, the orientation of the glazing

within any part of the building, but particularly the transition

space (because of its propensity for larger areas of glass) is very

important. Referring to Figs. 5–12 it appears that orientation

has little impact on layout types C and D however in both A and

B options cooling energy is lowest for transition spaces

orientated towards the North.

These results have potential practical significance to the

building industry, especially in the current climate of energy

price uncertainties. This type of information will be valuable at

stages of making the irreversible decisions about basic

orientation, layout and circulation with implications for future

operational costs. It is clear that more work is necessary

however to develop the concept and determine more clearly just

how wide a variation in thermal conditions occupants will find

acceptable for transition spaces. There is also a need to

incorporate findings with design and control of building

services systems and occupant use of buildings.

In summary several conclusions relevant to designers may

be inferred from the data and the foregoing analysis.

� I
t is plausible and reasonable to suggest that transition spaces
of buildings can be operated to a wider temperature tolerance

than their accompanying interior occupied spaces and still

achieve thermal comfort for those people passing through.

� S
ignificant reductions in heating energy use can be achieved
through the operation of transition spaces at lower than

normal temperatures.

� O
rientation has only a modest effect on heating energy use in
buildings with transition spaces.

� R
elatively minor reductions in cooling energy use are
possible for transition space buildings due to the impact of

heat gains.

� C
ooling energy requirements vary more significantly with
orientation—a southerly orientation for transition spaces

reduces energy use in the main occupied space by the greatest

amount but results in the highest transition cooling energy use

(the reverse being true for northerly orientated transition

spaces).

� W
here transition spaces are used they have greatest effect
where they give protection or buffering to the largest facade

areas (shown in this study as types A and D).

It is important for building designers to recognise the

important role of transition spaces in design and in energy use and

thus costs for buildings. Further detailed analyses are still

required however to gain a more holistic picture for the energy

consumption of common non-domestic building configurations

and this should be linked to more detailed studies of occupant

reaction in dynamic thermal situations. It would also be valuable

to investigate a wider range of building types and arrangements to

gain a more full understanding of this complex topic area.

References

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basic concepts: literature review and trial measurement, Building and

Environment 39 (10) (2004) 1187–1192.

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