It is estimated that about 4 million flats in Poland are made of prefabricated elements in different systems. Moreover, at present more than 10 million Poles live in system buildings. Despite the commonness of those buildings the analyses of the microclimate of the interior space are very rare. The paper presents the results of the thermal comfort measurements conducted in different flats of multi-family panel building made in W70 system. It appears there is a problem with the overheating effect during the summer months in all parts of the building

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	
Materials	and	Building	Structures,	Faculty	of	Civil	Engineering,	Cracow	University	of	Technology.
TECHNICAL TRANSACTIONS
CIVIL ENGINEERING
5-B/2014
CZASOPISMO TECHNICZNE
BUDOWNICTWO
KATARZYNA	NOWAK-DZIESZKO,	MAŁGORZATA	ROJEWSKA-WARCHAŁ*
MEASUREMENTS	OF	THE	THERMAL	COMFORT	 
IN	THE	W70	PANEL	BUILDING
POMIARY	KOMFORTU	CIEPLNEGO	W	BUDYNKU	
WIELKOPŁYTOWYM	W	SYSTEMIE	W70
A b s t r a c t
It	is	estimated	that	about	4	million	flats	in	Poland	are	made	of	prefabricated	elements	in	different	
systems.	Moreover,	at	present	more	than	10	million	Poles	live	in	system	buildings.	Despite	the	
commonness	of	those	buildings	the	analyses	of	the	microclimate	of	the	interior	space	are	very	
rare.	The	paper	presents	the	results	of	the	thermal	comfort	measurements	conducted	in	different	
flats	of	multi-family	panel	building	made	in	W70	system.	It	appears	there	is	a	problem	with	the	
overheating	effect	during	the	summer	months	in	all	parts	of	the	building.	
Keywords: panel building, W70 system, thermal comfort measurements, PMV (Predicted Mean 
Vote), PPD (Predicted Percentage of Dissatisfied)
S t r e s z c z e n i e
Szacuje	się,	że	w	Polsce	około	4	milionów	mieszkań	wykonanych	jest	w	technologi	wielkiej	
płyty	w	różnych	systemach.	Co	więcej,	obecnie	ponad	10	milionów	Polaków	mieszka	w	budyn-
kach	systemowych.	Pomimo	powszechności	 tychże	budynków	analizy	mikroklimatu	wnętrz	
jest	 bardzo	 rzadkie.	W	 artykule	 przedstawiono	wyniki	 pomiarów	 komfortu	 cieplnego	 prze-
prowadzonych	w	różnych	mieszkaniach	wielorodzinnego	budynku	wzniesionego	w	systemie	
W70.	Okazuje	się,	że	we	wszystkich	analizowanych	mieszkaniach	występuje	problem	prze-
grzania	w	miesiącach	letnich.	
Słowa kluczowe: budynek wielkopłytowy, system W70, pomiary komfortu cieplnego, PMV 
(Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied)
196
1. Prefabricated panel buildings 
In	 the	fifties	of	 the	 twentieth	 century	 the	 erection	of	panel	 system	buildings	began	 in	
Poland.	For	the	several	dozen	years	about	4	millions	flats	have	been	adjusted	to	use.	At	present	
more	than	10	million	Poles	live	in	system	buildings.	It	makes	the	problems	connected	with	
the	proper	usage	and	thermal	insulation	very	important	and	common.	The	thermal	insulation	
of	those	buildings	is	low	and	the	seasonal	heating	energy	demand	is	usually	50%	higher	than	
the	national	requirements	[1].	The	most	important	aspect	is	the	improvement	of	the	building	
energy	certificate	of	those	buildings.	It	is	connected	with	the	thermal	modernization	of	the	
building	envelope	and	change	of	windows.	
Unfortunately	at	the	stage	of	considering	and	designing	the	thermal	modernization	no-
one	takes	into	account	the	thermal	comfort	and	overheating	issues	in	summer	which	seem	to	
be	very	important	from	the	occupants’	point	of	view.	
The	W70	System	is	the	”opened”	system	used	for	the	erection	of	multi-family	buildings,	
in	 which,	 contrary	 to	 the	 “closed”	 system,	 all	 construction	 walls	 within	 the	 flats	 were	
eliminated.	It	allowed	the	changes	of	the	partition	wall	pattern	and	at	the	same	time	enabled	
designing	of	flats	with	different	areas	and	room	arrangements.	It	is	estimated	that	about	15%	
of	all	system	buildings	were	erected	this	way.
2. Thermal comfort
Thermal	 comfort	 is	 related	 to	 the	 thermal	 balance	 of	 the	 body	 which	 is	 affected	 by	
different	parameters:	personal	and	environmental.	The	microclimate	of	the	interior	space	is	
the	combined	effect	of	the	design	process,	erection	and	the	utilization	of	particular	rooms.	
Thermal	comfort	 is	affected	by	human	activity,	clothing	 insulation	and	 the	environmental	
parameters	such	as	air	temperature,	average	radiation	temperature,	air	flow	speed	and	relative	
humidity.	The	evaluation	of	thermal	comfort	is	based	on	the	PMV	(Predicted	Mean	Vote)	and	
PPD	(Predicted	Percentage	of	Dissatisfied)	indices.	
The	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”	[4]	uses	Fanger’s	method	to	estimate	
thermal	comfort.
The	 Fanger’s	 PMV	 method	 combines	 the	 following	 environmental	 features:	 air	
temperature,	air	velocity,	mean	radiant	temperature	and	relative	humidity	and	two	personal	
variables:	clothing	insulation	and	activity	level	into	the	index	that	can	be	used	to	predict	the	
average	 thermal	sensation	of	a	 large	group	of	people.	The	 thermal	sensation	7-level	scale	
with	values	between	–3	and	3	describes	the	thermal	sensation	between	“hot”	and	“cold”.	
In	 this	model,	 all	major	modes	 of	 energy	 losses	 from	 the	 human	body	 are	 taken	 into	
account	and	the	person	is	assumed	to	be	at	the	steady	state	condition.
197
3. Flats analyzed
The	aim	of	the	field	measurements	was	to	analyze	the	thermal	comfort	in	the	particular	
parts	of	the	W70	panel	dwelling	building,	built	in	1974	(Fig.	1).	The	tests	were	conducted	
using	the	digital	thermal	comfort	measurement	device	(Babuc),	Fig.	2	Infogap	program	to	
analyze	test	data.
																															a)																																															b)
Fig.	1a)	South	elevation	of	the	analyzed	building,	 
b)	location	of	flats	at	building	floor
Fig.	2.	BABUC	–	device	used	to	measure	
thermal	comfort
Building	plan	area	21.5	×	13.2	m;	usage	building	area	–	2279	m2,	25	m	high	with	11	
levels.	Basement	below	the	entire	building,	flat	roof.	
Building	with	the	natural	ventilation,	central	heating	system	with	convection	heaters.
Communication	area	located	in	the	center	part	of	each	building	level.	Four	flats	at	every	
story	located	in	the	corners	of	the	building.	
The	field	tests	were	conducted	in	three	flats	at	different	levels	and	with	different	window	
orientation:
1)	Flat	number	1	–	ground	floor,	South-East	orientation,
2)	Flat	number	2	–	fifth	floor,	South-West	orientation,
3)	Flat	number	3	–	seventh	floor,	North-East	orientation.
Exterior	walls	made	 of	 prefabricated	 panels	 in	W70	 system,	 insulated	with	 10	 cm	of	
styrofoam	with	plasters	at	both	sides:	U	=	0.25	[W/m2K],	double	glazing	windows:	U = 1.7 
[W/m2K].
198
4. Test results
The	main	aim	of	the	field	tests	was	to	analyze	the	microclimate	conditions	of	the	particular	
flats	at	different	elevations	during	summer.	Measurements	allowed	to	determine	the	internal	
operative	temperatures,	and	therefore	–	based	on	the	measurement	data	–	calculate	the	values	
of	PMV	index	and	PPD	index.
The	measurements	were	 conducted	 in	 three	 days	 between	 29th	 July	 and	 31st	 July,	 for	
24	hours	in	every	flat	referenced	above,	starting	at	seventh	floor,	next	of	the	fifth	floor	and	
finally	at	ground	floor.	 In	each	case	 the	measuring	device	was	 located	 in	 the	 living	 room	
where	the	percentage	of	glazing	at	exterior	walls	is	the	highest.	
The	average	external	 temperatures	during	 those	days	were	even	above	30°C	and	were	
measured	continuously,	 the	 results	are	presented	 in	Fig.	3.	The	electronic	device	used	for	
temperature	measurements	was	located	at	the	balcony	of	each	flat.
Fig.	3.	External	temperature	between	29th	and	31st	July	in	Cracow
In	all	dwellings	the	operative	temperature	in	the	analyzed	period	of	time	is	considerably	
higher	 than	 25°C.	 The	 daily	maximum	 interior	 operative	 temperature	 is	 29.17°C.	 Those	
negative	flat	conditions	continue	for	the	entire	day	and	do	not	change	significantly	at	night.	
The	flats	can	be	cooled	down	during	the	night	through	the	open	windows.	However,	in	case	
of	such	high	external	temperatures,	 it	doesn’t	change	the	operative	temperature	much.	All	
data	are	presented	in	Fig.	4.
Fig.	4.	Internal	operative	temperatures	between	29th	and	31st	July	in	the	analyzed	flats
199
The	thermal	comfort	conditions	are	closely	related	with	the	human	activity	and	clothing	
insulation.	The	parameter	clo	=	0.5	describing	clothing	 insulation,	based	on	 standard	 [3],	
was	assumed	in	the	calculations	of	PMV	index.	Regarding	human	activity,	two	cases	were	
calculated:	first	one	for	a	person	having	a	 rest	and	 the	second	one	for	a	person	doing	 the	
cleaning.	
Figure	5	presents	the	PMV	values	with	the	assumption	that	flat	users	have	a	rest.	For	most	
of	the	time	the	PMV	value	is	between	–0.5	and	0.5,	for	the	rest	of	the	time	it’s	higher	than	
0.5	but	not	more	than	1.	
Fig.	5.	PMV	index	–	users	having	a	rest
The	results	are	much	different	when	we	assume	different	activity	level	of	people	staying	
inside	 the	flats.	 Figure	 6	 presents	 the	 results.	The	PMV	values	 are	much	higher	 than	1.5	
almost	for	the	entire	period	of	time.	Those	are	not	comfortable	conditions	for	users.
The	predicted	percentage	of	dissatisfied,	described	by	PPD	index	in	the	analyzed	period	
of	time	is	between	50%	and	80%	(Fig.	7).	
Fig.	6.	PMV	index	–	users	cleaning	the	room
200
Fig.	7.	PPD	index	–	users	cleaning	the	room
5. Conclusions
The	results	of	conducted	analysis	show	that	the	overheating	problem	in	summer	occurs	
in	all	flats	of	the	panel	building.	Windows	in	the	prefabricated	panel	buildings	in	most	cases	
are	poorly	 shaded	 from	 solar	 radiation.	Glazing	 is	 the	 source	of	 the	 excessive	heat	 gains	
and	results	in	overheating	of	the	dwellings.	The	microclimate	conditions	in	all	flats	are	very	
uncomfortable	and	the	parameters	describing	thermal	comfort	exceed	the	acceptable	values.	
The	operative	temperatures	are	much	higher	than	25°C	and	the	PMV	values	for	most	of	the	
time	are	between	1.5	and	2	and	the	percentage	of	dissatisfied	people	for	all	the	time	is	higher	
than	50%.	
In	 case	 of	 all	 flats	 the	 internal	 or	 external	 shadings	 should	 be	 used	 to	 improve	 the	
microclimate	conditions	and	reduce	the	internal	operative	temperatures.	
R e f e r e n c e s
[1]	 Rozporządzenie	Ministra	Infrastruktury	w	sprawie	warunków	technicznych,	jakim	po-
winny	odpowiadać	budynki	i	ich	usytuowanie	z	dnia	12	kwietnia	2002.
[2]	 Ostańska	 A.,	 Wpływ dotychczasowych termomodernizacji budynków mieszkalnych 
na oszczędność energii i planowanie programów rewitalizacji na przykładzie jednego 
z lubelskich osiedli	Budownictwo	i	Architektura	7,	2010,	89-103.
[3]	 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.
[4]	 Nowak	K.,	Modernizacja budynków a komfort cieplny pomieszczeń,	Energia	i	Budynek,	
11	(54),	2011.
[5]	 Dębowski	J.,	Cała prawda o budynkach wielkopłytowych,	Przegląd	budowlany	9/2012.


Measurements of the thermal comfort in the W70 panel building

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Measurements of the thermal comfort in the W70 panel building

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