The thermal comfort conditions of multi-family buildings, including large panel buildings, are rarely analyzed. Simulations of large panel buildings conducted by authors in the Design Builder program show very unfavorable microclimate conditions in buildings after thermal modernization. The simulation results of the influence of internal and external shadings on the thermal comfort of dwellings in multi-family large panel building are presented in this article

Nowak-Dzieszko, Katarzyna

Rojewska-Warchał, Małgorzata

Portal Czasopism Naukowych (E-Journals)

* M.Sc. Eng. Katarzyna Nowak-Dzieszko, M.Sc. Eng. Małgorzata Rojewska-Warchał, Institute 
of Building Materials and Structures, Faculty of  Civil Engineering, Cracow University 
of   Technology.
KATARZYNA NOWAK-DZIESZKO*, MAŁGORZATA ROJEWSKA-WARCHAŁ*
INFLUENCE OF SHADING SYSTEMS  
ON THE MICROCLIMATE CONDITIONS  
IN LARGE PANEL BUILDINGS
WPŁYW ZACIENIEŃ NA WARUNKI MIKROKLIMATU 
W BUDYNKU WIELKOPŁYTOWYM
A b s t r a c t
The thermal comfort conditions of multi-family buildings, including large panel buildings, 
are rarely analyzed. Simulations of large panel buildings conducted by authors in the Design 
Builder program show very unfavorable microclimate conditions in buildings after thermal 
modernization. The simulation results of the influence of internal and external shadings 
on the thermal comfort of dwellings in multi-family large panel building are presented in this 
article.
Keywords: large panel building, internal and external shading system, thermal comfort 
of  the panel buildings, PMV (Predicted Mean Vote), PPD (Predicted Percentage 
of  Dissatisfied)
S t r e s z c z e n i e
Warunki komfortu cieplnego wielorodzinnych budynków mieszkalnych, w tym budynków 
wielkopłytowych, są analizowane bardzo rzadko. Symulacje budynków wielkopłytowych 
przeprowadzone przez autorów w programie Design Builder wykazały bardzo niekorzystne 
warunki mikroklimatu w budynkach po termomodernizacji. W artykule przedstawiono wyni-
ki symulacji wpływu zacienień wewnętrznych oraz zewnętrznych na komfort cieplny lokali 
mieszkalnych w wielorodzinnym budynku wielkopłytowym.
Słowa kluczowe: budynek wielkopłytowy, zacienienia zewnętrzne i wewnętrzne, komfort 
cieplny w budynkach wielkopłytowych, PMV, PPD
TECHNICAL TRANSACTIONS
CIVIL ENGINEERING
3-B/2014
CZASOPISMO TECHNICZNE
BUDOWNICTWO
372
1. Description of problem
In considering and designing thermal modernization, no one takes into consideration 
the thermal comfort and overheating issues which seem to be very important from 
the occupants’ point of view. The thermal modernization of the large panel buildings 
is usually limited to the insulation of external walls and the replacement of windows, 
which significantly reduces the energy demand. Unfortunately, those treatments negatively 
affect the microclimate conditions inside buildings. The modernization process should 
be more complex and solutions for reducing the problem of overheating should be 
taken into consideration. The usage of internal and external shading was analyzed based 
on the simulations conducted in the Design Builder program.
Analysis of thermal comfort is based on international standard PN-EN ISO 7730 
“Ergonomics of the thermal environment. Analytical determination and interpretation 
of  thermal comfort using calculation of the PMV and PPD indices and local thermal comfort 
criteria” [1].
2. Description of analyzed building
Conducted simulations allowed the influence of internal and external shadings 
on the thermal comfort in the particular parts of the analyzed five-storey large panel building 
to be analyzed. The simulations were conducted for a part of a W70 multi-family panel 
building ‒ basement below entire building, flat roof. Visualizations of different building 
elevations are presented in Fig. 1.
The building has natural ventilation and a central heating system with convection 
heaters. There is a communication area located in the central part of each building level. 
In the analyzed part of the building, there are three flats on every level. Exterior walls made 
of prefabricated panels in the W70 system, insulated with 15 cm of styrofoam with plasters 
at both sides: U = 0.20 [W/m2K], double glazed windows: U =1.5 [W/m2K]).
The calculations were carried out in the Design Builder v.3. This program has been 
specifically developed around Energy Plus allowing the simulation of the building envelope 
and building interiors. The simulations conducted for the Polish climatic conditions (building 
located in Cracow) allowed for the evaluation of the microclimate conditions of the entire 
building as well as of particular dwellings.
Fig. 1. South-east and south elevations of analyzed building
373
3. Simulation settings
The main aim of simulations was to determine the temperature and PMV index 
of  the particular flats at different elevations during the summer months. Figure 2 presents 
a typical arrangement of dwellings on the building storey.
Every single flat was modeled as a separate thermal comfort zone due to the small usage 
area of different flats. It was assumed that the doors between rooms are usually opened. Three 
different flats were analyzed:
1. Flat M1 – usage area 56 m2, balcony at south elevation.
2. Flat M2 – usage area 31 m2, balcony at south elevation.
3. Flat M3 – usage area 36 m2, balcony at east elevation.
According to the recast to the European Energy Performance of Buildings Directive, 
buildings designed and modernized after 2021 should be zero-energy buildings. In connection 
with those provisions, since 1st of January 2014, the new requirements regarding building 
envelope thermal insulation were introduced in Warunki Techniczne 2013 [4]. According 
to those regulations, thermal transmittance U of the heated building components cannot 
exceed 0.25 W/m2K and after 1st of January 2021, 0.2 W/m2K.
The starting point for further analyzes was the simulation of the building with the external 
walls modernized to the standard being in force since 2021.
The assumptions for the simulations: 
1. Heating system on from September to March (22°C), 7 days a week, 24 hours a day.
2. Occupancy density: flats – about 1 person per 15 m2,
3. Operating schedule: flats – 100% occupancy density between 4 pm and 7 am, 5 days 
a week; between 6 pm and 9 am at the weekends; 50% reduced occupancy between 9 am 
and 6 pm. 
4. Metabolic activity: 1.2 met, winter clothing – clo = 1.0, summer clothing clo = 0.5.
5. Ventilation requirements per polish national standards PN-83/B-03430 [2], in every flat 
70 m3/hour for kitchens and 50 m3/hour for bathrooms.
Fig. 2. Typical zones’ visualization at every building level
374
Table 1 presents the number of discomfort hours in the analyzed period of time between 
15th of May and 15th of September hours in all analyzed dwellings on different levels. In this 
particular period of time in Poland, there is the highest risk of overheating.
T a b l e  1
Number of discomfort hours for all analyzed flats at different levels
Number of overheating hours
M1
1st level 946
2nd floor 1235.5
3rd floor 1477
4th floor 1746.5
M2
1st level 1391.5
2nd floor 1916
3rd floor 2225.5
4th floor 2392
M3
1st level 1377
2nd floor 1718
3rd floor 1985
4th floor 2153.5
The worst thermal conditions can be observed on the fourth level in flat M2 at 
the south-east corner of the building. The total number of hours in the analyzed period of 
time is 2952 which means that for more than 80% of hours in flat M2, temperatures are above 
the acceptable value of 25°C. Those conditions are very uncomfortable for the occupants. 
In practice, those hours are being lessened by night cooling of the internal space through 
the opening of windows. At the lowest levels however, due to security reasons, this kind 
of  solution cannot be used widely.
In many flats, occupants use the internal shading systems (shading panels) to decrease 
the solar gains. In the next step of simulations, the influence of internal shadings 
on the microclimate conditions was analyzed.
Figures 3a and 3b present the number of overheating hours for flat M2 at different levels 
with and without internal shading. The number of discomfort hours decreased as follows:
– at the first floor – from 1391 to 1307 – 6% decrease,
– at the second floor – from 1916 to 1829 – 5% decrease,
– 3rd floor – 2225 to 2126 – 4% decrease,
– 4th floor – 2392 to 2348 – only 2% decrease.
Internal shading systems only slightly decreased the number of overheating hours.
The next step of simulating the external shading system consisted of four steel louver 
blades (width 20 cm) covering 1m height of all windows. This solution again improved 
the thermal comfort conditions and decreased the number of overheating hours. Table 2 
shows the number of overheating hours in three simulation steps.
375
In case of flat M2 on the fourth floor, the number of discomfort hours was lessened by 
a further 2%, which gives a total decrease of only 4% from 2392 to 2304.
The most significant improvement of thermal conditions, about 14% decrease 
of  discomfort hours from 1235.5 to 1064, can be noticed in flat M1 due to the biggest usage 
area of this particular flat. However, this is still not a considerable improvement compared 
to the installation cost of external shading systems.
Fig. 3a. Number of overheating hours for flat M2 at different levels – without any shading
Fig. 3b. Number of overheating hours for flat M2 at different levels – with internal shading
Fig. 4. PMV comfort indexes for flat M2 without any shading and with internal shading system
376
T a b l e  2
Number of discomfort hours for all analyzed flats without any shading, with internal shading 
and with both internal and external shading systems
Number of discomfort 
hours – without any 
shadings
Number of discomfort 
hours – with internal 
shadings
Number of discomfort 
hours – with internal 
and external shadings
M1
1st level 946 891,5 836,5
2nd floor 1235,5 1135,5 1064
3rd floor 1477 1388,5 1314
4th floor 1746,5 1656,6 1581,5
M2
1st level 1391,5 1307,5 1218
2nd floor 1916 1829,5 1727
3rd floor 2225,5 2126 2055,5
4th floor 2392 2348 2304
M3
1st level 1377 1305 1246
2nd floor 1718 1638,5 1572,5
3rd floor 1985 1916 1852,5
4th floor 2153,5 2081 2038,5
4. Conclusions
The results of the conducted analysis show that the microclimate conditions in all flats 
of the building after thermal modernization are very uncomfortable and the parameters 
describing thermal comfort exceed the acceptable values. Using different shading systems, 
internal and external ones, only slightly reduce the number of overheating hours during 
summer months. The smaller the usage area of the analyzed dwelling, the lower the reduction 
of discomfort hours.
The work reported in this paper has been partially funded by the project L-1/116/DS/2013.
Fig. 5. PMV comfort indexes for flat M1 without any shadings and with internal 
and external shading systems
377
R e f e r e n c e s
[1] PN-EN ISO 7730 Ergonomics of the thermal environment. Analytical determination and 
interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal 
comfort criteria.
[2] PN-83/B-03430 Wentylacja w budynkach mieszkalnych  zamieszkania zbiorowego i użyteczności 
publicznej – Wymagania.
[3] Rozporządzenie Ministra Infrastruktury z dnia 12 kwietnia 2002 w sprawie warunków tech- 
nicznych, jakim powinny odpowiadać budynki i ich usytuowanie (Dz.U. nr 75, poz. 690 z późn. 
zm. ogłoszonymi w Dz.U. z 2003 r. Nr 33, poz. 270, z 2004 r. Nr 109, poz. 1156, z 2008 r. Nr 201, 
poz. 1238, z 2009 r. Nr 56, poz. 461, z 2010 r. Nr 239, poz. 1597, z 2012 r. poz. 1289 oraz z 2013 r., 
poz. 926.
[4] Rozporządzenie Ministra Transportu, Budownictwa i Gospodarki Morskiej z dnia 5 lipca 2013 r. 
zmieniające rozporządzenie w sprawie warunków technicznych, jakim powinny odpowiadać 
budynki i ich usytuowanie (Dz.U. z 13 sierpnia 2013 r., poz. 926).
[5] Nowak K., Modernizacja budynków a komfort cieplny pomieszczeń, Energia i Budynek, 29-33.
[6] Dębowski J., Cała prawda o budynkach wielkopłytowych, Przegląd budowlany 9/2012.
[7] Nowak K., Nowak-Dzieszko K., Rojewska-Warchał M., Thermal comfort of the rooms 
in the designing of commercial buildings, Research and Applications in Structural Engineering, 
Mechanics and Computation, SMEC Cape Town 2013, 651-652.



Influence of shading systems on the microclimate conditions in large panel buildings

http://www.ejournals.eu/sj/index.php/Cz/article/download/1494/1492

Influence of shading systems on the microclimate conditions in large panel buildings

Abstract

Similar works

Full text

Available Versions

Portal Czasopism Naukowych (E-Journals)