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The history of the radiant heating and cooling systems is discussed. There is anecdotal reference to early 8th century radiant cooling using snow-packed walls in buildings constructed in Mesopotamia in Turkey with cooled water and much later in 20th century Europe. Pre-World War II radiant cooling included 'The historic Reichstag building the German parliament was at the time of its inauguration in December of 1894 one of the most sophisticated and technically advanced buildings of its time. Since the later part of the 20th century, industry has developed better understanding of controls for radiant-cooled environments and with dedicated outdoor air systems and improved controllability larger applications of cooling developed in extreme climates like Bangkok with its cooled Suvarnabhumi Airport system. It is also reported that since 2005, the number of commercial radiant system specifications has increased by 36% with 7.5% of new construction specifying radiant systems, a number expected to double by 2013.
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50 ASHRAE Journal February 2010
Part 1, published in January, covered developments of radiant heating and cooling in Asia.
From the third century B.C., ancient Europe developed an underfloor heat-
ing system called Hypocaustum.1 The system was defined by the furnace 
(hypocausis) and a series of flue passages realized under the floor by means of 
pillars carrying a slab and then exhausted through cavities in the walls.
Roman oyster farmer, Gaius Sergius
Orata was commonly thought to have in-
troduced or developed this type of heating
during the first century B.C. However, “Hy-
pocausts of the third and second centuries
B.C. are known, for instance, at Gortys in
Greece and at Gela, Megara Hyblaea, and
Syracuse in Magna Graecia.2 Additionally,
the use of floor heating in ancient European
and Middle Eastern lands was widespread
with variations of the hypocaust found in
Afghanistan,3 Syria,4 and other countries.5
With the exception of late antiquity
hypocaust type systems in the Middle
East, Europe’s use of floor heating went
into hibernation for many centuries while
systems in Korea, China and parts of Japan
continually evolved.
Rebirth in Europe
Between the 12th and 17th centuries,
open fires were used in Europe, the
Middle East and North America. The
Russian Fireplace, the Steinofen and
Kachelofen in Europe, and the Tandoor
with Tab-khaneh (other spellings include
tanur/taba khana) in Afghanistan6,7 lead
up to the development of the 18th century
By Robert Bean, Member ASHRAE; Bjarne W. Olesen, Ph.D., Fellow ASHRAE; Kwang Woo Kim, Arch.D., Member ASHRAE
About the Authors
Robert Bean is a registered engineering technolo-
gist (building construction) with Healthy Heating in
Calgary, AB, Canada. Bjarne W. Olesen, Ph.D., is
director, professor, International Centre for Indoor
Environment and Energy, Technical University of
Denmark in Lyngby, Denmark. Kwang Woo Kim,
Arch.D., is a professor of architecture at Seoul
National University, Seoul, Korea.
History of
Radiant Heating
& Cooling Systems
Part 2
Hypocausts were used from the
third century B.C. in ancient
This article was published in ASHRAE Journal, February 2010. Copyright 2010 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Posted
at This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about
ASHRAE Journal, visit
February 2010 ASHRAE Journal 51
c. 1600, France,
heated ues in oors
and walls used in
c. 1800 Beginnings of
the European evolu-
tion of the modern
water heater/boiler
and water based pip-
ing systems including
studies in thermal
conductivities and
specic heat of materi-
als and emissivity/
reectivity of surfaces
c. 1864, ondol type
system used at Civil
War hospital sites in
America. Reichstag
building (shown above)
in Germany uses the
thermal mass of the
building for cooling and
Photo credit: Daniel Schwen
c. 1700 Benjamin
Franklin studies the
French and Asian cul-
tures and makes note
of their respective
heating systems lead-
ing to the development
of the Franklin stove.
Steam based radi-
ant pipes are used in
c. 1904, Liverpool
Cathedral (England)
heated with system
based on the hypo-
caust principles.
Image credit: Smithsonian Institution
Image credit: U.S. National Park Service
Franklin Stove, which became a preferred heating system in
many buildings.8
Floor heating in Europe reappeared during this era. “John Ev-
elyn, writing in 1691, indicated that heating greenhouses by the
radiation from flues in floors and walls was by no means a novelty,
(and it) is…believed that the technique was a survival from clas-
sical times in Russia but had been lost in the rest of Europe.9,10
From Stetiu, “…(the) hot water boiler was introduced around
this time, together with its system of large pipes through which the
hot water was carried. The first known such design is attributed
to Sir John Stone, who installed a heating system
of pipes in the Bank of England in 1790.11,12
However, a parallel evolution existed in other
countries with time lines offset by only a few
decades. Also at this time was the development
of the understanding of radiant heat transfer.
“John Leslie discovered in 1801 that the dimin-
ished output of James Watts’ 1784 tin plate steam
radiator had to do with its emissivity, discover-
ing that a coat of pigment to a metallic surface
greatly enhanced its output.”13
Benjamin Thompson, who determined the
specific heats of various substances and thermal
conductivities of insulating materials, observed
in the 1800s:
Close to the windows it will indeed be possible to feel the
heat caused by the calorific radiations; but nothing can
hinder the currents of air, caused by the cooling, which
takes place through the panes of glass, from spreading
over the entire extent of the room. But when the windows
are double layer, the layer of air which is enclosed between
the two windows being an excellent non-conductor of heat,
the inside window is well protected from cold from without
and the descending currents of air just mentioned no longer
existing, it would be easy, with good stoves moderately
heated to establish a pleasant and equable temperature.13
Today’s thermally activated building systems are foreshad-
owed in this quote: “…a Mr. Hay of Edinburgh proposed an
early form of thermal storage to heat a building using steam
to heat stone-filled pits in each room. The stones were heated
once a day as required.13
Two significant patents leading up to modern-
day fluid based systems were issued during this
century to Angier March Perkins. The first in
1839 was for an “apparatus for transmitting heat
by circulating water, and the second in 1841 was
for an “apparatus for heating by the circulation
of hot water; construction of pipes for such and
other purposes.”14
Also during this period we see the beginning
of the end for hypocaust type systems when King
Edward VII laid the foundation stone in 1904 to
what was to become Liverpool Cathedral.“The
whole floor of the Nave, Transept and Chancel
forms one large radiator and it was reputed to be
the largest single radiator in the world.15 Then just a few years
later: “The modern development of radiant heating started in
1907(8), when Arthur H. Barker, a British professor, discovered
that small hot water pipes embedded in plaster or concrete
formed a very efficient heating system.”16
Hypocaust flues from Ro-
man baths.
52 ASHRAE Journal February 2010
c. 1905, Frank Lloyd
Wright makes rst trip
to Japan, later incor-
porates various early
forms of radiant heat-
ing in his projects.
c. 1907, England,
Prof. Barker granted
Patent No. 28477 for
panel warming using
small pipes. Patents
c. 1930, Faber in
England uses water
pipes to radiant heat
and cool several large
c. 1933, explosion
at England’s Imperial
Chemical Industries
(ICI) laboratory during
a high pressure experi-
ment with ethylene gas
results in a wax like
substance later to
become polyethylene
and the beginnings of
PEX pipe.
c. 1937 Frank Lloyd
Wright designs the
radiant heated Herbert
Jacobs house, the rst
Usonian home.
later sold to the
Crittal Company who
appointed representa-
tives across Europe.
A.M. Byers of America
promotes radiant
heating using small
bore water pipes. Asia
continues to use tradi-
tional ondol and kang
– wood is used as the
fuel, combustion gases
sent underoor.
Photo credit: James Steakley
Image courtesy of Dan Holohan
An earlier 1800s version is the John Soane house and
museum, “Here the architect, after trying a number of expedi-
ents, turned to the newly developed Perkins high pressure hot
water system…he could conceal the small bore pipes under
the bases of the marble antiquities in the Belzoni Chamber,
place a coil of pipes under the table in the Monk’s Room, and
run a circuit of piping around the base of his many skylights
to counter the flow of cold air….”9 Patent No. 28477 was
granted on Barker’s system of heating, which was called
panel warming.17
This patent was later sold to R. Crittal & Company Limited
who used the concepts to heat the Royal Livre building in
Liverpool in 1909. Crittal appointed representatives in several
countries including Sulzer Brothers of Winterthur, Switzer-
land. It conducted extensive long-term studies with the Swiss
National Research Laboratory.18 During this era, systems were
installed in an open air school in Amsterdam (1929), a private
residence in Germany (1930) and a large department store in
Zurich (1936–38).17 At this time came the impetus for a reevalu-
ation of radiant piping systems stemming from an accidental (re)
discovery of polyethylene by Gibson and Fawcett in 1933 at the
ICI laboratories in England, which later led to the development
of PEX pipe and a solution to many challenges associated with
earlier piping materials.18
Introduction of Radiant Cooling Systems
There is anecdotal reference to early 8th century radiant
cooling using snow-packed walls in buildings constructed
in Mesopotamia (modern day Iraq),19 in Turkey with cooled
water11 and much later in 20th century Europe where “After
the war, the Bank of England got a nice new hydronic radi-
ant heating system that was installed under the direction of
a fellow named Dr. Oscar Faber. Dr. Faber’s system used
copper pipes embedded in concrete floors and plaster ceil-
ings and it was used to cool the building in the summer and
heat it in winter.20
Pre-World War II radiant cooling included “The historic
Reichstag building—the German parliament—was at the time
of its inauguration in December of 1894 one of the most so-
phisticated and technically advanced buildings of its time. The
design incorporated central heating, humidification and summer
‘cooling’ with the help of thermal mass.21
Solving the Issue of Latent Loads
“Most of the early cooling ceiling systems developed in the
1930s failed…because condensation often occurred…. Subse-
quent studies showed that this problem could be avoided if the
radiant system was used in conjunction with a small ventilation
system designed to lower the dew-point of the indoor air. This
combination proved successful in a department store built in
1936-1937 in Zürich, Switzerland and in a multi-story building
built in the early 1950s in Canada.11
Since the later part of the 20th century, industry has developed
a better understanding of controls for radiant-cooled environ-
ments and with dedicated outdoor air systems and improved
controllability larger applications of cooling developed in
extreme climates like Bangkok with its cooled Suvarnabhumi
Airport system.22
North America
In the 18th century, Benjamin Franklin studied radiant floor
heating in Asia and French technology to develop his Franklin
February 2010 ASHRAE Journal 53
c. 1939 rst small
scale polyethylene
plant built in America.
c. 1945 American
developer William
Levitt builds large
scale developments
for returning G.I.s (see
photo above). Water
based (copper pipe)
radiant heating used
throughout thousands
of homes.
c. 1950, Korean War
wipes out wood sup-
plies for ondol; popu-
lation forced to use
coal. Developer Joseph
Eichler in California
begins the construc-
tion of thousands of
radiant heated homes.
c. 1951 Dr. J.
Bjorksten of Bjorksten
Research Laboratories
announces rst results
of what is believed to
be the rst instance
of testing three types
of plastic tubing for
radiant oor heating in
c. 1965, Thomas
Engel patents method
for stabilizing polyeth-
ylene by cross link-
ing molecules using
peroxide (PEX-A) and
in 1967 sells license
options to a number of
Stove. Edgerton shares a story of Franklin writing to a friend
in Boston about stoves he had seen in the Bank of England.
By means of an elaborate down draft, the smoke was drawn
through tubes in the center of the stoves themselves and out
under the floor by means of ducts to the chimneys. This tech-
nological feat intrigued Franklin and he thereupon designed
his own interpretation, which consisted of an urn on a ped-
estal, all within a cast-iron niche in the chimney. He added
another idea which the French had actually explored before,
of having the smoke consumed as it passed through the fire.
The smoke which collected in a tile
urn was drawn down through the
stove, burned, and the unadulter-
ated hot air went under the floor,
warmed up the hollow niche, and
radiated into the room.23
Roughly a century later, rudimen-
tary forms of radiant heating were
used during the American Civil War:
The plan which…gave the utmost
satisfaction, was that known as
the California plan. A pit was dug
about two-and-a-half feet deep
outside the door of the hospital
tent; from this a trench passed
longitudinally through the tent, terminating outside its
farther or closed extremity. At this point a chimney was
formed by barrels placed one upon the other, or by some
other simple plan. The joints and crevices of this chimney
were cemented with clay. The trench in the interior of the
tent was roofed over with plates of sheet-iron issued for
that purpose by the Quartermasters Department. A fire
was built in the pit, and the resulting heat, radiating from
the sheet-iron plates, kept the interior of the tent warm
and comfortable even in the coldest weather.24
The description is remarkably similar to versions used in
ancient Asia. One could speculate that the term “California
Plan” came from the west coast Chinese immigrants who
influenced those around them during those times leading up
to the civil war.25 According to J. Lawrence, project coordina-
tor of Sheridan’s Field Hospital at Shawnee Springs, there is
some evidence that the heating system was adopted from the
frontiers during the gold rush in the 1840/50s.26
Most Chinese immigrants entered California through the
port of San Francisco...(they) formed part of the diverse
gathering of peoples from throughout the world who con-
tributed to the economic and population explosion that
characterized the early history of the state of California…
(and) brought with them to the United States traditions and
practices that were integral to their daily lives.25
Following the Civil War era, the
A.M. Byers Company published that
“In 1909 a small school was con-
structed in the Village of Glen Park,
Indiana. Pipes carrying steam were
suspended between the floor joist,
over which conventional wood floors
were laid.” “…in 1911, wrought iron
heating coils were placed behind steel
plates in the walls of certain rooms
in the Phipps Psychiatric Clinic in
Baltimore. This institution is part of
John Hopkins Hospital.”
The influence of early British
systems is shown with these words
from the Chase Brass & Copper Co.: “The early successes of
Radiant Heating on the Continent and in England so aroused
the interests of certain engineers in the United States as to lead
Professor Theodore Crane of the Yale School of Fine Arts to
undertake in 1910 the design and installation of probably one
of the first of this country’s technically designed systems.”27
Another important radiant heated project in the U.S. was the
British Embassy in Washington.27
It was during this time American architect Frank Lloyd
Wright popularized the use of radiant heating. As Franklin be-
fore him, Wright was influenced by Asian architecture and radi-
ant heating even before he made his first trip to Japan in 1905.
It is interesting that I, an architect supposed to be con-
cerned with the aesthetic sense of the building, should have
invented the hung wall for the w.c. (easier to clean under),
Image courtesy of Dan Holohan
Levittown house built by developer William Levitt as
part of the first mass-produced suburb in U.S.
54 ASHRAE Journal February 2010
c. 1970 evolution of
Korean architecture
leads to multistory
housings. Flue gases
from coal based ondol
results in many deaths
leading to the removal
of the home based ue
gas system to a central
water-based heating
plant. Oxygen perme-
ation becomes corro-
sion issue in Europe.
c. 1980 The rst
standards for oor
heating are developed
in Europe. Water-
based ondol system is
applied to almost all
residential buildings in
c. 1985 oor heating
becomes a traditional
heating system in
residential buildings
in Middle Europe and
Nordic countries, and
applications in non-
residential buildings
c. 1995 The applica-
tion of oor cooling
and TABS (Thermo
Active Building
Systems) in residential
and commercial build-
ings are widely intro-
duced into the market.
c. 2000 The use
of embedded radi-
ant cooling systems
in Middle Europe
becomes a standard
system with many
parts of the world
applying radiant based
HVAC systems as
means of using low
temperatures for heat-
ing and high tempera-
tures for cooling.
and adopted many other innovations like the glass door,
steel furniture, air-conditioning and radiant or ‘gravity
heat. Nearly every technological innovation used today was
suggested in the Larkin Building in 1904.28
Wright was a pioneer in radiant floor heating, using it in many
of his projects such as the Johnson Wax Building (1937) and
the Jacobs Residence.
Following the end of World War II, the U.S. had its first
large-scale multi-building project heated with radiant systems
realized with copper pipes embedded in a concrete slab in his- in his-
toric Levittown.29 In all there was to be 2,000 homes built in
the New York project with radiant heating using copper pipe.
Thousands more were built, including those later constructed
by California developer Joseph Eichler.18
In Canada, the use of radiant heating found application
in the early 1960s home of an NRC researcher who writes,
“Decades later it would be identified as a passive solar house.
It incorporated innovative features such as the radiant heating
system supplied with hot water from an automatically stoked
anthracite furnace.”30
Market Acceptance
As noted in Part I, almost all buildings in Ko-
rea (95%) and Northern China (85%) use radiant
floor heating31 with strong growth showing in
Japan. In Europe, fluid-based systems dominate
the construction industry.32 Unlike Asia and
Europe, the combined general market share for
residential hydronic/steam systems in Canada
and the United States is a nominal 5% with the
volume closely following on the rise and fall of
building permits. The exception is when home
owners become directly involved in the HVAC
decision-making process resulting in a 10% to
12% use. Approximation based on hydronic data
available from Stats Canada and U.S. Census
Bureau. It is also reported that since 2005, the number of com-
mercial radiant system specifications has increased by 36% with
7.5% of new construction specifying radiant systems, a number
expected to double by 2013.33
Larkin Administration Building, Buffalo, N.Y. Designed by Frank
Lloyd Wright, it was one of the first to use radiant floor heating.
1. D’Ambrosio, F.R., et al. 2006. “Sulla termotecnica in epoca ro-
mana.Proceedings of Storia dell’Ingegneria.
2. Fagan, G.G. 1996. “Sergius Orata: inventor of the
hypocaust?” Phoenix 50(1):56 66.
3. Rashti, C., et al. 2007. “Urban Conservation and
Area Development in Afghanistan,” pp. 10, 12. Aga
Khan Historic Cities Programme.
4. Kennedy, H. 2005. “From Polis to Madina: urban
change in late antique and early Islamic Syria.” Past
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5. Chennaoui, Y. 2009. “Architectural correlation
analysis of the hammams of Cherchell, Algeria:
linear vs aggregate space in the traditional bath.”
International Journal of Architectural Research
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6. Emadi, H. 2005. Culture and Customs of Afghani-
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7. Yoldas, C. 2004. A Prototypical (School) Design
Strategy for Soil-cement Construction in Afghanistan, Ph.D. thesis,
Kansas State University.
8. Manley, J.K. 1954. Radiant Heating, Radiant Cooling. School of
Architecture, Pratt Institute.
1950s controls for radiant
Image credit: Dan Holohan
Photo credit: Jerome Puma private collection
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9. Bruegmann, R. 1978. “Central heating and forced ventilation:
origins and effects on architectural design.” The Journal of the Society
of Architectural Historians 37(3):143 160.
10. Bean, R., B. Olesen, K.W. Kim. 2010. “History of radiant heating
& cooling systems: Part I.” ASHRAE Journal 52(1):40 – 47.
11. Stetiu, C. 1998. Radiant Cooling in U.S. Office Buildings: Towards
Eliminating the Perception of Climate-Imposed Barriers, Chapter 2.
Ph.D. thesis, Energy and Resources Group, University of California,
12. Adlam, T.N. 1949. Radiant Heating, Second Edition, p. 9. N.Y.:
The Industrial Press.
13. Dufton, A.F. 1940 – 41. “Early application of engineering to the
warming of buildings.” Newcomen Society Transactions.
14. Chartered Institution of Building Services Engineers. Heritage
Group Web site:
15. Adlam, T.N. 1949. Radiant Heating, Second Edition, p. 107.
N.Y.: The Industrial Press.
16. Adlam, T.N. 1949. Radiant Heating, Second Edition, p. 9. N.Y.:
The Industrial Press. (Some references cite 1907, and others cite
1908. The authors speculate the system was developed in 1907 and
later patented in 1908.)
17. Giesecke, F.E. 1947. Hot-water Heating and Radiant Heating and
Radiant Cooling, p. 20.2. Austin, Texas: Technical Book Company.
18. Bean, R. 2007. “History and influence of PEX pipe on indoor en-
vironmental quality.”
19. Tadworth, B.M.R. 2009. The Story of Comfort Air Conditioning
An Introductory Essay, The Evolution of Office Buildings and Air Con-
ditioning, p. 4. Chartered Institution of Building Services Engineers,
Heritage Group.
20. Smith, S., J. Sweet. 2004/2006. “A brief history of radiant heat-
ing.” Reeves Journal (1).
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Automotive Research Center With Radiant Cooling Floors.” 1st In-
ternational Intelligent and Green Building Technologies and Products
Conference & Expo Beijing, China.
22. Dixon, J.M. 2007. “Murphy/Jahn joins engineers Werner Sobek
and Matthias Schuler to bring Suvarnabhumi Airport, Bangkok’s sleek
new air terminal, in for a landing.” Architectural Record (8).
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25. U.S. Library of Congress. 2003. “The Chinese in California,
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26. Lawrence, J., J. Whitehorne, C. Geier. 2006. Correspondence.
27. Chase Brass & Copper Co. 1945. Chase Radiant Heating Manual,
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Wright, pp. 137 – 138. Horizon Press.
29. Bean, R. 2008. “Radiant heating and cooling part I—history.”
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... Space heating via the radiant surface is a proven technology in Nordic countries and is used extensively in residential buildings. Almost all buildings in Korea have radiant floor heating installed (up to 95%); the installation number is 80% in Northern China [3]. ...
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Energy use for heating and cooling at the household level is rising annually. The residential sector consumes about 69% of energy consumption, out of which the highest percentage is shared by traditional fuel for cooking applications, followed by heating and cooling applications. In such a scenario, the primary goal should be to meet future heating and cooling energy demand through the use of novel technologies such as radiant heating systems (RHS). By utilizing low-temperature fluid flowing through the pipe, the RHS is more efficient than a standard heating system in maintaining the correct interior temperature. These systems are not frequently implemented in Nepal. It is crucial to compare the applicability of the system with technologies like radiator systems. The building provided by Urban Development and Building Construction (UDMC) is used for the study. The radiant and radiator heating system is designed, and the effects of different parameters on the heat transfer coefficient are studied. The maximum heating load is 50kWh for mid of January. A radiant heating system with a panel area of 18.24m ² is sufficient to satisfy the heating demand, while radiator heating requires a panel area of 3.6m ² . To meet the same load, the total pipe length for the radiant and radiator heating systems is 300m and 42m, respectively. Radiant and radiator heating systems had a heat transfer coefficient of 7.76W/m ² and 15.34W/m ² , respectively. The variation is because the radiator system must provide the same amount of heat to the building while having a smaller surface area than the radiant heating system.
... Recent advances in building control systems and indoor air quality requirements revived interest in RCSs, especially when integrated with a dedicated outdoor air system (DOAS). 34 RCSs application was extended from mild climates where condensation issues are minimal to hot and humid climates. ...
Heating and cooling requirements in modern buildings are considerably high, where the building sector contributes 40% to the current end-use energy consumption, and its related CO2 emissions have increased by 1% in the past decade only. Different novel solutions have been proposed in the literature to reduce energy consumption and peak loads while maintaining the same thermal comfort levels within the building envelope. The use of phase change materials (PCMs) as thermal energy storage media is a promising concept for storing energy as latent heat and then releasing it when the temperature is lower than the melting point. This has the potential of shifting and dampening peak loads and stabilizing space air temperatures. PCMs can be integrated into the well-established low-temperature radiant heating technologies and/or the emerging high-temperature radiant cooling ones for additional benefits of enhanced thermal comfort, system size reduction, and annual energy savings. Multiple review articles on radiant systems or the application of PCMs in modern buildings are available in the literature, but there are no review articles focused on the interaction between the two technologies. This review article provides a brief background and a gentle introduction to radiant heating and cooling systems (RHCSs), as well as the use of PCMs in modern building applications. Then, the article comprehensively reviews the relatively limited state-of-the-art research on the use of PCMs in RHCSs to better understand the research progress and identify research gaps and questions to be tackled in future research. The literature shows a generally favorable impact of PCMs on radiant systems, with heating and cooling energy savings up to 54% and 50%, respectively, extended comfortable occupied hours by more than two folds, system cost reductions up to 5%, and payback periods of as low as 3.32 years. Some discrepancies exist among reported studies, especially regarding the performance of PCMs in dual mode (heating and cooling) systems, which is mainly due to the lack of clear integration schemes. It is concluded that the merits of using PCMs in RHCSs are outstanding, but the existing studies are not nearly sufficient to address such complex and dynamic systems. Hence, different future directions have been highlighted to accelerate the progress of this research field, including the need for optimizing the relative position of PCM layers, studying the economic aspects of using PCMs, detailed experimental case studies of full-scale buildings, user-friendly numerical models, and advanced control strategies to handle the slow thermal response of the PCM in RHCSs.
... However, the ceiling cooling system cannot be used alone to control indoor thermal environment due to the lack of mechanical ventilation systems [4][5], so a ceiling cooling system is normally combined with a mechanical ventilation system, e.g. a mixing ventilation system, a displacement ventilation system or an underfloor air distribution system [6][7][8] . In the 21th century, a ceiling cooling system integrated with a mechanical ventilation system is an advanced HVAC system for the modern office building with glass curtain wall [9][10] . ...
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A ceiling cooling (CC) system integrated with a mechanical ventilation system is an advanced HVAC system for the modern office building with glass curtain wall. In this paper, considering the influence of heat transfer of external envelope, the indoor thermal environment and human thermal comfort were objectively measured and subjectively evaluated in a ceiling cooling room with mixing ventilation (MV) or underfloor air distribution (UFAD). Indoor physical parameters and human skin temperatures were measured as the chilled ceiling surface temperature and supply air temperature were 17.1?C-17.6?C and 22.2?C - 22.6?C. Simultaneously, 16 subjects (8 males and 8 females) were selected to subjectively evaluate the thermal environment. The results showed that the difference between mean radiant temperature and air temperature in the occupied zone was 0.8?C with CC+MV and 1.2?C with CC+UFAD, and the indoor air velocity was 0.17m/s with CC+MV and 0.13m/s with CC+UFAD. In addition, the calculated and measured thermal sensation votes with CC+MV were all slightly less than those with CC+UFAD. Therefore, ventilation system type had a slight impact on the indoor thermal environment and human thermal comfort in the ceiling cooling room.
Fossil fuel firing heating systems will be substantially abandoned in the near future due to the zero-carbon goals. They will be replaced with heating systems that use renewable energy sources. Since the investment costs and area requirements of the renewable energy systems are high, the developments of highly efficient electric fluid heating systems have critical importance for a sustainable, environmentally friendly and clean heating. Among the electrical heating systems, induction heaters offer quite easy to use and better adaptability to most heating systems by allowing fluid heating without the necessity for contact. In this paper, a comprehensive review of the evolution of the induction fluid heaters is given by presenting the historical background. The most important milestones of induction fluid heating systems are presented. The development strategies suggested by the different papers including patents are investigated. The findings revealed that induction fluid heating systems, which reach approximately 100% thermal efficiency. These systems are introduced as follows: clean, non-emitting fluid heating system. Because of this, the study concludes that induction fluid heaters are one of the most promising alternatives to other electric heating systems in the long run.
Radiant cooling system (RCS), along with dedicated outdoor air system (DOAS) is an appropriate system to enhance energy efficiency and maintaining better thermal comfort conditions compared to the compression based system. In general, DOAS uses a fan coil system to dehumidify the air which consumes a significant amount of energy. This chapter describes desiccant wheel based dehumidification system for DOAS using the solar energy for the desiccant regeneration. Different dehumidification techniques were discussed in the chapter using the simulation study conducted on the software (EnergyPlus). A reference medium scale office building was considered for simulation study. Impact of RCS operated by compression and absorption based system and coupled with desiccant assisted DOAS was designed for the office building and involvement of solar energy towards the annual energy consumption were investigated. The comparative analysis shows the energy saving potential and feasibility of absorption system for RCS against the compression system. The simulation study was conducted for two climatic conditions i.e. warm‐humid and hot‐dry climate. The simulation results realize the energy saving potential of later case up to 10.91% and 28.7% for warm‐humid and hot‐dry conditions, respectively. Next, the contribution of solar energy can be ensured up to 99%.
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Radiant floor heating is becoming increasingly popular in cold climates because it delivers higher comfort levels more efficiently than conventional systems. Wood is one of the surface coverings most frequently used in radiant flooring, despite the widely held belief that in terms of thermal performance it is no match for higher conductivity materials if a high energy performance is intended. Given that the highest admissible thermal resistance for flooring finishes or coverings is generally accepted to be 0.15 m2K/W, wood would appear to be a scantly appropriate choice. Nonetheless, the evaluation of the thermal performance of wooden radiant floor heating systems in conjunction with the building in terms of energy demand, thermal comfort, and start-up period, has been insufficiently explored in research. This has led to the present knowledge gap around its potential to deliver lower energy consumption and higher thermal comfort than high-thermal-conductivity materials, depending on building characteristics. This article studies the thermal performance of wood radiant floors in terms of three parameters: energy demand, thermal comfort, and start-up lag time, analysing the effect of wood properties in conjunction with building construction on each. An experimentally validated radiant floor model was coupled to a simplified building thermal model to simulate the performance of 60 wood coverings and one reference granite covering in 216 urban dwellings differing in construction features. The average energy demand was observed to be lower in the wood than in the granite coverings in 25% of the dwellings simulated. Similarly, on average, wood lagged behind granite in thermal comfort by less than 1 h/day in 50% of the dwellings. The energy demand was minimised in a significant 18% and thermal comfort maximised in 14% of the simulations at the lowest thermal conductivity value. The vast majority of the wooden floors lengthened the start-up lag time relative to granite in only 30 min or less in all the dwellings. Wood flooring with the highest thermal resistance (even over the 0.15 m2K/W cited in standard EN 1264-2) did not significantly affect the energy demand or thermal comfort. On average, wood flooring lowered energy demand by 6.4% and daily hours of thermal comfort by a mere 1.6% relative to granite coverings. The findings showed that wood-finished flooring may deliver comparable or, in some cases, higher thermal performance than high-conductivity material coverings, even when their thermal resistance is over 0.15 m2K/W. The suggestion is that the aforementioned value, presently deemed the maximum admissible thermal resistance, may need to be revised.
Radiant cooling systems have the potential of reducing energy when compared with conventional air-conditioning systems. Thermal comfort evaluations for radiant cooling systems mainly focused on floor heating, chilled ceiling, and warm/cool wall, few have been known about the radiant floor cooling system. To validate the applicability of existing dissatisfaction models on radiant floor cooling systems, a field survey with continuous environmental measurements and subjective questionnaires was carried out in an office building in Shanghai. The results show that radiant asymmetries can affect occupants’ thermal comfort and acceptance rate significantly. The radiant floor cooling tends to cause more local discomfort complaints in the feet and calf parts than other radiant heating and cooling systems. The relationship (equation) between thermal dissatisfaction and asymmetrical radiations was developed, and the temperature thresholds s for the radiant floor cooling system were calculated. Based on these results, the short-term (2 hours) and long-term (8 hours) exposures at different levels of asymmetric radiation were compared and showed significant differences in occupants’ thermal satisfaction. The phenomenon of multi-directional asymmetric radiations (vertically and horizontally) was also observed and its effects were explored. Lastly, the design considerations, thermal comfort assessment, energy consumption, and operation strategy for the radiant floor cooling system were discussed.
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This study reviews water-based wall systems for space heating and cooling and thermal barriers (TB) for the reduction of buildings’ thermal load. The review gives a general overview of the research and groups it into subtopics that are discussed in detail. For space heating and cooling, the subtopics entail thermal performance, thermal comfort, renewable energy sources, use for building retrofit, and combination with phase change materials (PCM). For TB, especially the working principle, types and designs, and performance are discussed. A classification system is proposed separately for wall heating and cooling systems and TB based on the designs found in scientific literature. Benefits and drawbacks are summarized, and design recommendations are provided for the wall systems. It was shown that in certain cases, radiant wall systems can be preferable to radiant floors and ceilings, but further comparisons would be useful to provide conclusive evidence. For TB, the studies uniformly declare that TB reduce buildings’ thermal loads and energy demands. Few studies focused on the economic and environmental aspects of using TB. Most of the studies about TB are based on calculations. Measurements to quantify the benefits of TB under real operation and refine the conditions under which various types of TB are feasible are lacking. Enhancing the wall performance by PCM in the active layer, application of the wall systems in building retrofit, and alternating between the functions of heating, cooling, and TB present the biggest research opportunities and challenges.
Control of the heating and cooling system needs to be able to maintain the indoor temperatures within the comfort range under the varying internal loads and external climates. To maintain a stable thermal environment, the control system needs to maintain the balance between the heat gain/loss of the building and the supplied energy from the system. Several studies in the literature deal with control.1-4.
The evidence for Sergius Orata and his "hanging baths" (pensiles balineae) is subjected to close scrutiny and shown to be insufficient for securing Orata's role as the inventor of the hypocaust. Rather, the evidence suggests that pensiles balineae were fishponds of some sort. As a result, Orata ought to be excluded from the history of Roman baths. / L'auteur réexamine les documents concernant Sergius Orata et ses "bains suspendus" (pensiles balineae) et démontre qu'on ne peut pas les utiliser pour attribuer à Orata le rôle de l'inventeur de l'hypocauste. Ces documents suggèrent plutôt que les pensiles balineae étaient en fait des espèces de viviers. Le nom d'Orata doit donc être biffé de l'histoire des bains romains.
The three major methods of heating buildings, based on hot air, hot water, and steam, were all developed in the late 18th and early 19th centuries, largely in Great Britain. At the same time, forced ventilation, based either on the drawing power of heat or on the use of mechanical means like the fan, was also established. The greatest application of the new equipment was made by the engineer David Boswell Reid at the Houses of Parliament starting in 1834. Many problems had to be overcome. Medical doubts about ventilation, the rivalry between architects and engineers, and difficulties in reconciling design with equipment were all attacked, and by the last quarter of the 19th century largely solved. Publications of the last two decades of the century standardized the technology and made it readily available to the architect, engineer, and general public. Use of the new technology made possible many new architectural developments. Prison, theater, greenhouse, and hospital were all largely dependent on central heating and forced ventilation. In other building types new levels of comfort and increased standards of safety were made possible. Perhaps the most profound change was in the conception of the building itself. Buildings could be seen literally in terms of living organisms or machines. Reid even defined architecture as the act of enclosing and servicing an interior atmosphere, a notion not developed until the 20th century.
Chinese kangs are widely used today, in nearly 85% of rural homes by 175 million people in Northern China. While Chinese kangs are a potentially energy sustainable solution for home heating, existing systems are characterized by their poor energy efficiency and significant concerns about the impact of indoor air pollution in homes caused by smoke backflow or smoke leakages. Existing kang designs are based on the intuition and historical accumulation of past craftsmanship experiences. As the first attempt, a macroscopic thermal-fluid approach is used to model the airflow and heat transfer process of an elevated kang with a focus on smoke flow. This model considers nonlinear interaction of thermal buoyancy force, wind force and heat transfer from kang plates and chimney walls. Five parameter groups are identified for characterizing the kang systems to guide the kang smoke flow design. Our work has explained the so-called smoke backflow phenomenon that can lead to serious indoor air quality problems in rural homes and based on the results, we have provided some design recommendations for avoiding smoke backflowand for enhancing energy efficiency by increasing the heat utilization of the kang body.
Much attention is being given to improving the efficiency of air-conditioning systems through the promotion of more efficient cooling technologies. One such alternative, radiant cooling, is the subject of this thesis. Performance information from Western European buildings equipped with radiant cooling systems indicates that these systems not only reduce the building energy consumption but also provide additional economic and comfort-related benefits. Their potential in other markets such as the US has been largely overlooked due to lack of practical demonstration, and to the absence of simulation tools capable of predicting system performance in different climates. This thesis describes the development of RADCOOL, a simulation tool that models thermal and moisture-related effects in spaces equipped with radiant cooling systems. The thesis then conducts the first in-depth investigation of the climate-related aspects of the performance of radiant cooling systems in office buildings. The results of the investigation show that a building equipped with a radiant cooling system can be operated in any US climate with small risk of condensation. For the office space examined in the thesis, employing a radiant cooling system instead of a traditional all-air system can save on average 30% of the energy consumption and 27% of the peak power demand due to space conditioning. The savings potential is climate-dependent, and is larger in retrofitted buildings than in new construction. This thesis demonstrates the high performance potential of radiant cooling systems across a broad range of US climates. It further discusses the economics governing the US air-conditioning market and identifies the type of policy interventions and other measures that could encourage the adoption of radiant cooling in this market.
Thesis (M. Arch.)--Kansas State University, 2004. Includes bibliographical references (leaves 122-127).
La civilisation urbaine qui, en Occident, s'est effondree sous les coups des invasions barbares, a continue a s'epanouir en Orient, mais en subissant des changements qui, en plusieurs siecles, transformerent la polis antique en madina islamique. Exemple de la Syrie.