MOKSLAS – LIETUVOS ATEITIS ISSN 2029-2341 print / ISSN 2029-2252 online

SCIENCE – FUTURE OF LITHUANIA 2011 3(3): 38–44 doi:10.3846/mla.2011.049

K. Šešelgio skaitymai – 2011

K. Šešelgis’ Readings – 2011

URBAN DEVELOPMENT EFFECT ON PASSIVE HOUSE

ENERGY CONSUMPTION

Edgars Suvorovs
Riga Technical University, Riga, Latvia
E-mail: edgars.suvorovs@rtu.lv

Abstract. The paper describes one of the energy-efficient building concepts – a passive house. In the course of the work, a
multifamily residential house was simulated in order to determine its constructive and spatial parameters that would ensure
a passive house with energy efficiency in compliance with the fixed standards. The climatic data of the Latvian capital, Riga,
were applied to this building simulation. Initially, an optimal orientation and maximum theoretical insulation of the building
were chosen. At the second stage, the external factors – the shade caused by the surrounding buildings and effect of the buil-
ding orientation dictated by the existing urban conditions – were studied based on the previously achieved energy efficiency
rating. The results evidenced that the layout of window apertures and change of orientation, as well as shading caused by the
surrounding buildings, plaid a significant role in the rating of the building energy efficiency nonetheless it did not interfere with
achieving the passive house standards.

Keywords: energy-efficient house, passive house orientation.

Introduction
companies offer to provide both a passive house quality
In European architecture and construction industry an control and production of windows and doors in accor-
increasingly greater attention is being paid to the energy dance with the passive house standards. Thereby one can
efficiency issues. This is facilitated both by the effect of forecast that in years to come all the conditions will be
global processes on the design practice and by low effi- fulfilled for successful implementation of the passive house
ciency of the traditional designing practice, which is no concept on a wider scale than before. Besides, in the ne-
longer consistent with surging prices of energy resources. arest ten years the designing of energy-efficient buildings
In Latvia the energy efficiency of the housing fund is very will become a statutory provision, after enactment of the
low – the specific energy consumption by the mass resi- European Directive’s requirements stating that after 2020
dential buildings for heating per annum makes up about all newly erected buildings must be almost zero-energy
180 kWh/m² (Blumberga 2006). Nevertheless, at present buildings (Directive 2010/31/EU 2010).
in Latvia a number of examples of implemented energy- A passive house as a type of an energy-efficient buil-
efficient construction projects is still very low, while the ding is widely known in many European countries, parti-
number of renovated multifamily houses is increasing, and cularly in Germany, Austria and Switzerland. In the Baltic
thus being actively reported in the Latvian media. More States only the first implemented examples still exist. The
and more various training workshops are organized for passive house criteria under the conditions of Central Europe
architecture and construction industry professionals on the were defined at Passive House Institute in Darmstadt – the
principles of designing of energy-efficient buildings, also Research and Consulting Centre under the auspices of Dr
updating issues on the possibilities of implementation of Wolfgang Feist. The passive house concept is based on
the passive house concepts in Latvian climatic conditions. the idea, according to which comfortable to people indoor
Demand for the passive house design courses among temperature can be provided without using any traditio-
professionals is high, because up to now the principles nal heating system. This can be achieved by minimizing
of passive house designing have not been included into the building heat loss thanks to the high performance of
the process of training of architecture specialists. Also the structures and air-tightness of the building (Table 1).
the material and technical basis does not preclude from Therefore the heat emitted from the equipment available
dissemination of the passive house concept in Latvia: indoors, the people and the solar thermal energy received
the heating efficiency of structures can be ensured using through windows shall be enough to ensure the indoor tem-
traditional building materials, but more and more local perature. During cold winter months an additional necessary

© Vilniaus Gedimino technikos universitetas

http://www.mla.vgtu.lt 38
heat quantity can be provided with warmed air supplied by A bit more optimistic conclusions were made by a
the ventilation system. Ventilation is necessary because of physicist Ainis Builevics, who made a passive house cal-
the air-tightness of the building in order to provide neces- culation for a 120 m² two-storey residential house with
sary air change, but, to reduce the heat loss through the an ideal orientation, giving a desired indoor temperature
ventilation system the application of a recuperation system of about 20 °C. According to the calculation in order to
is a must (Feist et al. 2007). achieve the passive house standard it is required 700 mm
Not only the individual parameters of the structure of rockwool for thermal insulation of the walls and roof,
play the most important role in achievement of the passive 700 mm of polystyrene foam for thermal insulation of
house standard, but also the building’s architectonic spatial the floor and the double glazed windows with heat pene-
organization, and particularly, the cardinal orientation of tration U = 0,6 W(m²K), window frame heat penetration
window openings, because a lot of energy is lost through U = 0,7 W(m²K), and the ventilation thermal efficiency
the windows. Usually it is recommended to position the 92% (Builevics 2007).
largest glazing in a building facing the south, as in this
case windows with high thermal parameters can ensure that Table 2. Passive house parameters under Latvian climatic con-
ditions (Passive House Latvia 2010)
solar heat obtained through windows will be greater than
the quantity of lost energy (Feist et al. 2001). However, Walls, U-value <0,10 W/(m²K)

it is necessary to consider that in summer there might be Ground slab, U-value <0,10 W/(m²K)
a risk of overheating therefore it is necessary to construct Roof, U-value <0,10 W/(m²K)
the shading of windows. Windows, total U-value <0,8 W/(m²K)
Ventilation heat recovery efficiency, ηHR ≥80%
Table 1. Passive house parameters (Feist et al. 2007) Air-tightness of the building envelope 0, 6 h-1
Walls, U-value <0,15 W/(m²K) (Air leakage at a pressure differential
50 Pa)
Ground slab, U-value <0,15 W/(m²K)
Specific heating energy consumption ≤15 kWh/(m²a)
Roof, U-value <0,15 W/(m²K)
Heating load ≤10 W/m²
Windows, total U-value <0,8 W/(m²K)
Ventilation heat recovery efficiency, ηHR ≥75%
Air-tightness of the building envelope (Air 0,6 h-1 Since 2009, in Latvia, an association Passive House
leakage at the pressure differential 50 Pa) Latvia has been engaged in organization of the energy-ef-
Specific heating energy consumption ≤15 kWh/(m²a) ficient building design training workshops and mainstrea-
Heating load ≤10 W/m² mification of the idea. Passive House Latvia recommends
the minimum requirements to observe in order to achieve
the passive house standard under Latvian climatic condi-
Passive House Parameters Exposed to tions (Table 2). The first house designed pursuant to the
Latvian Climatic Conditions passive house principles is the one-family residential buil-
The passive house standard was originally developed and ding “Lielkalni” in Gipka village, Roja rural municipality
widely used in the area of Central Europe, but the clima- (Fig. 1).
tic conditions in the Baltic Sea region are much harsher.
Different calculations have been made in Latvia in order to
make certain on feasibility of achievement of the passive
house standard under such climatic conditions.
The RTU specialists carried out a passive house si-
mulation in TRNSYS software for the Latvian climatic
conditions, taking as a basis a 160 m² one-family two-
storey residential house. The paper describes two options
of buildings with different building parameters. In both
cases it was concluded that it is problematic to ensure the
minimum heating load required by the passive house stan-
dard. This means that for such building a heating system
is necessary, since warming by ventilation air would be Fig. 1. Single family house “Lielkalni” in Ģipka, Latvia 2009
insufficient (Kamenders 2007). (late construction stage), E. Krauklis

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 The thermodynamic parameters of the house (Table 3) effect of the existing urban environment as an external factor
are very close to the passive house standards, however, on the building energy consumption. The consideration of
they failed to achieve thereof, as the optimal orientation this issue is essential for several reasons. First, the building
against the cardinal direction was not provided (due to the compactness ratio or volume-to-size ratio, expressed in the
underground stream network), as well as due to the window building envelope area against the building heated area,
position (architectural and practical considerations). Thus, at is essential for the energy-efficient building design and
present, Latvia has no building built fully in accordance with achievement of the passive house standard. The bigger is
the passive house standards. In comparison to the passive the external surface area, the greater is heat loss through
house criteria for the Central European climate condition the external surfaces. A multifamily building per se is a
defined by the Passive House Institute in Darmstadt, much more compact solution than a single-family low-rise buil-
higher criteria are necessary in order to attain the passive ding. Therefore, in architecture of a multifamily house, it
house standards in the Baltic region, as evidenced by the is potentially easier to achieve the passive house standard,
recently finished buildings designed applying the passive because the energy loss through the external surfaces, in
house principles (Table 3). relation to the heated area, is less than in one-family buil-
As evidenced by the listed theoretical and practical dings. Secondly, insulation of a passive house in winter
examples, the passive house criteria up to now have been can provide an essential part of the building with neces-
considered mainly in architecture of single-family buildings sary heat generation. Since in urban environment, other
located in the environment free from other spatial objects. buildings cast additional shade to a projected building, a
Having studied the publicly accessible passive house data- passive house placed in the real urban situation can recei-
base on the Internet, as well as various examples of passive ve a substantially smaller amount of solar heat radiation
houses constructed in Europe, one can conclude that the through windows, but this, as evidenced by the above re-
majority of passive houses have been designed in the en- ferred practical example, can interfere with achieving the
vironment free from other structures, and less frequently passive house standard. When designing a building in an
in an urban environment. Also, estimations performed in undeveloped environment an architect is free to operate
Latvia are mostly oriented to calculation of passive house with cardinal orientation of window openings, estimating
parameters for free environment conditions, focusing on the balance of the building energy. Amid dense urban de-
determination of technical parameters of a passive house. velopment this is much more difficult, because orientation
So far, less attention has been given to achievement of the of a building is restricted by the plot position, as well as
passive house standard in a high-rise construction and the the surrounding development situation. The character of

Table 3. Examples of the energy-efficient houses in the Baltic Region

*
Single family house “Lielkalni” **
Single family house in Vilnius, *
Kindergarten in Valga
in Gipka (Latvia) Antakalnis (Lithuania) (Estonia), reconstruction
Completion date 2009 2004 2009
Walls, U-value 0,071 0,118 0,1
(W/m²K)
Roof, U-value 0,053 0,076 0,07
(W/m²K)
Ground floor, 0,076 0,11 0,12
U-value (W/m²K)
Windows, U-value 0,8 0,67 (glazing) 0,51 (glazing),
(W/m²K) 0,65 (frame) 0,74 (frame)
Specific space 26 26 <30
heat demand
(kWh/(m2a))
* (Passive Through Active 2011)
** (Built Passive Houses 2011)

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the impact of the surrounding development in such a case ding design thermodynamic and geometric parameters.
plays both negative and positive role. The shading cast by PHPP software has been tested in practice and improved,
the surrounding buildings reduces the quantity of energy while designing many passive houses and comparing real
received through windows, thereby resulting in a negative results with calculations.
effect on the building energy consumption index in winter,
but mitigating the building overheating risk in summer. Definition of parameters of the
However, it is possible to fight overheating by applying simulated house
basic arrangements, ensuring the window darkening, but, if
Since the climatic conditions play an essential role in the
it is necessary to position the building windows against the
passive house simulation, already at the initial stage it
north, which is often unavoidable, the quantity of energy
was necessary to choose a particular geographic location
lost through windows might become very significant in the
with known climatic data. Within the framework of the
total balance of the building energy.
Project, the climatic data of the capital of Latvia, Riga
The fact that in the structure of urban development it
city, were applied. The initial house simulation was car-
is impossible to vary freely the orientation of the building,
ried out, choosing the optimal orientation (orienting the
is another obstacle that interferes with accurate following of
front façade southwards) pursuant to the passive house
all of the passive house designing provisions and thereby
designing principles and assuming that the building would
theoretically compromises the achievement of the passive
be located in an environment completely free from other
house standards as well. This article attempts to clarify the
spatial objects. In this way, the building would receive the
significance of spatial orientation of a plot and impact of
maximum quantity of solar thermal radiation, possible in
surrounding development on the passive house parameters.
the local climatic conditions.
The building spatial parameters were defined follo-
Objectives of the Project, tasks wing the Riga construction regulations, which regulate
and applied methods
construction in a perimeter development situation close
The objective of the Project was to analyze the building to the historical centre of Riga. On this basis, the buil-
parameters thanks to which it would be possible to achieve ding height of 21,3 m to the eaves was selected, which
the passive house standard in a multifamily house in the accordingly meant that 6 storeys could be located in the
existing development structure under the Latvian climatic building, (Fig. 2). As the building prototype, one section of
conditions, also finding out how much the urban spatial a high-rise residential house (an apartment block grouped
environment, as an external factor, affects the energy with one staircase) was chosen assuming that in a perimeter
consumption by a passive house. development situation only two facades would be the most
The Project was implemented in several stages: common, as the other two would be blocked by the adjacent
− Theoretical definition of the building’s geometrical
parameters based on the Riga construction regula-
tions and functional fundamental requirements.
− Definition of thermodynamic parameters of the
building structures, ensuring the achievement of
the passive house standard in a spatially free envi-
ronment without shading and with optimal orien-
tation.
− Placing the obtained building simulation in a real
urban environment and simulation of energy con-
sumption, with due allowance for the effect of the
defined external factor of real urban environment,
i.e., shade and orientation against the cardinal di-
rection.
For the simulation of a passive house there was ap-
plied PHPP 2007 software, developed by the Darmstadt
Passive House Institute for designing of a passive house.
The software has a Table Excel file to enter various buil- Fig. 2. Geometrical model of the simulated building

41
buildings. For the purpose of insulation requirements the an abstract building layout and placing windows on both
depth of the building was assumed 12 m, but the section southern and northern facades of the building, within a year
length 20 m, which enabled to connect to one staircase the total heat loss through the windows would be larger
three apartments – one, two and three-room apartments. than the heat gain (13038 and 10633 kWh/a accordingly).
So, in total 18 apartments were planned in the building. If to place all windows only on the southern side, then
the heat loss and gains would be 13083 and 14306 kWh/a
Table 4. Parameters of the simulated building accordingly. Therefore also the placement and orientation
Walls, U-value* 0,093 W/(m²K) of windows in the design of an energy-efficient building
Ground slab, U-value **
0,099 W/(m²K) refer to an essential factor to follow by when planning
Roof, U-value ***
0,068 W/(m²K) the building.
Windows, total U-value 0,77 W/(m²K)
Ventilation heat recovery efficiency, ηHR 90% Urban Environment Impact on the
Air-tightness of the building envelope (Air 0, 6 h-1 Obtained Results
leakage at a pressure differential 50 Pa)
At the next stage it was assumed that the building with
Specific heating energy consumption 7 kWh/(m²a)
the resulting parameters will be placed in the perimeter
Heating load 10 W/m²
development block in the centre of Riga. The centre of
* in situ reinforced concrete with 450 mm insulation Riga is characterized by the perimeter development with
** reinforced concrete panel with 380 mm insulation
*** reinforced concrete panel with 500 mm insulation the typical 21.3 m and 24 m maximum building volume
height of the eaves. Selection of the site is determined by
The thermodynamic parameters of the simulated the factor that this urban development situation entails
building design were assumed with due allowance for the quite serious restrictions on the building insulation, the
recommendations of the Passive House Latvia (Table 4). building orientation against the cardinal points, moreover,
Since due to the existing development situation it was im- this is a typical development in the structure of Riga cons-
practicable to observe the optimal orientation of the building truction. For data entry it was assumed that the building
window openings, the area of windows was reduced to would locate in a particular place in the Skolas Street,
attain the passive house standard. As a result the minimum Riga (Figure 3). Due to the existing development situation
windows and floor area ratio was ensured according to the the simulated building had to be rotated by 47° from the
requirements by the Latvian statutory instruments. The area theoretically optimal orientation. As a result the specific
of the south-exposed windows was taken as 20% of the heating energy consumption of the building per annum in-
illuminated floor space, but the area of the north-exposed creased up to 8 kWh/m² or by 14%, the heat load remained
windows was 12,5% or 1/8 of the illuminated floor space. unchanged, but the overheating risk increased by 4%, due
This was the maximum window area, with which it was to which it was necessary to provide for additional shading
possible to provide that the heat load for heating would of windows in summer, unless shaded by the adjacent
not exceed 10 W/m² at the assumed design parameters. building. Therefore the next step was to evaluate shading
As a result, the building specific energy consumption was cast by the surrounding buildings. As a result the specific
achieved 7 kWh/m² per annum ensuring the minimum cri- heating energy consumption increased up to 9 kWh/m²,
teria of the passive house standard. However, the reduced but due to shading the overheating risk was mitigated and
size of windows combined with significantly thicker than no other additional cooling arrangements were necessary.
usually walls reduced the access of direct daylight into the The heat load remained at the previous level. The passive
room, as well as reduced the visual view angles through the house standard requirements were ensured.
windows. These problems in the process of real designing The passive house standard was attained despite of
can be solved by changing the shapes of the edges of the non-observance of the optimal orientation of the building
window openings. and additional shading from the surrounding urban deve-
During calculations it was observed that even due lopment. Besides, the standard was achieved with com-
to slight enlargement of the window area the heat load paratively similar parameters of the building structures as
exceeds the passive house criteria and in order to compen- previously mentioned in calculations made by other authors.
sate that it is necessary to increase significantly the heat Here, obviously, an important role belongs to the factor of
insulating properties of the envelope structures. This could compactness of the building, because the works of other
be explained by the fact that in a particular case assuming authors deal with small single-family houses, where the

42
 simulated one-family residential buildings in the same
climatic conditions. This is explained by the fact that a
multifamily residential house is a more compact cons-
truction type, where the heat loss through the external
envelope is less in relation to the heated area, especially
in the viewed perimeter development situation, where
the building in fact has only two external walls.
2. Due to a specific multifamily house layout the windows
were placed on both facades of the building, which
produced a bottleneck to achieve the passive house
standards. Therefore the sizes of windows in this hou-
se prototype were comparatively small. The building
layout in the further work process should be more
elaborated, with due allowance for the fact that it is not
advisable to position windows on the northern side,
in this way the façade composition to a larger degree
depends on the functional organization of the layout.
3. The calculation process showed that the specific energy
consumption for the chosen building parameters per
Fig. 3. The building location in Skolas Street, Riga
annum will be provided with a reserve, but it would be
more difficult to fulfill the minimum heat load requi-
heat loss through the external surfaces if compared with the
rements. This is also consistent with the passive house
heated area of the building, in general, is higher than in a
calculations made by other authors under the Latvian
multi-storey apartment house. Besides, the results obtained
climatic conditions.
in the course of modeling also do not significantly differ
4. Placing the building in a real development situation,
from already viewed examples of built passive houses in the
changing its orientation by 47 degrees and causing
Baltic region. Still, an urban environment creates additional
additional shade from the adjacent buildings, increased
encumbrances to achievement of the passive house standard,
the specific energy consumption required for heating
during designing it is necessary to reckon that the building
of the building by 22%, however, the passive house
must be much more compact and much greater reduction
standards have been fulfilled. Despite the fact that
of sizes of the windows than estimated during designing
surrounding buildings significantly affect the energy
a building in a free environment might be necessary, con-
consumption of a passive house, their impact is not
sequently involving more careful assessment of exposure
an obstacle to the implementation of a passive house
of the interior to sunlight and of the façade composition.
concept also in the historical urban development.
The building model was developed in the abstract the-
5. The obtained results evidence that it is impossible
refore it was not analyzed proceeding from the requirements
to define precisely the spatial parameters of passive
of architectonic expression. However, the obtained front
house architecture for the building in general within a
window proportions roughly correspond to the proportions
particular climatic region, because the achievement of
of the historical development windows against the total
necessary parameters is significantly affected by the
façade area, which can be assessed positive. The façade
building three-dimensional composition, the façade
architectonic composition in further designing should be
window composition and orientation of the building
solved by applying the façade plastics, finishing materials
against the cardinal points. In different situations and
and differentiation of the window opening sizes, preserving
for different building types (a single-family building, a
the calculated area of window openings.
multifamily building) the passive house standard can
be achieved with slightly different design parameters,
Conclusions therefore during the designing process an individual
1. The passive house criteria for the multifamily house calculations must be always applied.
managed to be fulfilled with slightly lower design
thermodynamic parameters than for the previously

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Aknowledgements
The work was performed within the framework of the 2nd year
of study under a PhD programme, supported by the European
Social Fund within the project “Support for the implementation
of doctoral studies at Riga Technical University”.

References
Blumberga, A.; Nikolajevs, A. 2006. Daudzdzīvokļu dzīvojamo
ēku energoefektivitātes analīze Latvijā [Analysis of Energy
Efficiency of Multifamily Buildings in Latvia]. Rīgas
Tehniskās universitātes zinātniskie raksti. 4.sēr., Enerģētika
un elektrotehnika [Scientific Journal of Riga Technical
University. Series 4, Power and Electrical Engineering] 17:
212–220.
Builevics, A. 2007. Pasīvās mājas modelis Latvijas klimatiska-
jos apstākļos [Passive House Prototype in Latvian Climatic
Conditions], Latvijas Būvniecība 5: 72–76.
Built Passive Houses [online]. 2011 [cited 28 March 2011].
Available from Internet: <http://www.passivhausprojekte.
de/projekte.php>.
Directive 2010/31/EU of the European Parlament and of the
Council of 19 May 2010 on the energy performance of
buildings, Official Journal of the European Union [online], L
153, 18.6.2010: 13–35 [cited 28 March 2011]. Available from
Internet: < http://eur-lex.europa.eu/LexUriServ/LexUriServ.
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Feist, W.; Peper, S.; Gorg, M. 2001. CEPHEUS-Projectinformation
No. 36. Final Technical Report. Hanover: Passivhaus Institut.
127 p.
Feist, W., et al. 2007. Passive House Planning Package 2007.
Darmstadt: Passive House Institute.
Kamenders, A.; Blumberga, A. 2007. Energy Efficient One
Family House Development in Latvia, Rīgas Tehniskās uni-
versitātes zinātniskie raksti. 4.sēr., Enerģētika un elektroteh-
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Passive House Latvija [online]. 2010 [cited 15 December
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MIESTO PLĖTROS ĮTAKA PASYVAUS NAMO

ENERGIJOS VARTOJIMUI
E. Suvorovs

Santrauka

Straipsnyje nagrinėjama viena iš energiją tausojančių pastatų

formų – pasyvus namas. Atliekant konstrukcijų ir erdvinio
planavimo parametrų tyrimus, buvo imituojamas daugiabutis
gyvenamasis namas, turėjęs užtikrinti pasyvaus namo energijos
taupymą ir atitikti visus standartus. Imitaciniam modeliui buvo
pasirinkti Rygos miesto klimatiniai duomenys. Rezultatų išvados
byloja, kad langų padėtis ir aplinkinių namų šešėliavimas daro
esminę įtaką energiniam namo efektyvumui, bet, nepaisant to,
įmanoma atitikti pasyvaus namo standartus.

Reikšminiai žodžiai: energiją taupantis namas, pasyvaus namo

orientacija.

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