HVAC APPLICATIONS
In 2016, the CTI (Italian Thermotechnical Committee) published the technical report UNI
TR 11619, which defines the normative references and the calculation methodology
for determining the energy efficiency index of radiant systems for heating and cooling
with low temperature difference, in the floor, wall and ceiling versions in compliance
with the EN 1264 standard, combined with strategies for regulating, balancing and
controlling the circulation pumps.
The index defined by the technical report considers the performance of:
- emission of the radiant system (ηe)
- thermoregulation of the ambient air and the heat transfer fluid (ηrg)
- balancing of circuits (ηbal)
- circolating pumps (ηcirc)
RSEE index
The energy efficiency index, called RSEE (Radiant System Energy Efficiency), is
expressed as a product of the yields of the various systems and components of the
system:
RSEE = ηe ∙ ηrg ∙ ηbal ∙ ηcirc
The overall efficiency of a system can vary considerably: the most significant factor
is the choice of temperature control devices (the values vary from 0.91 to 0.99).
ηrg represents the control efficiency and is directly influenced by the design choices
(such as the independent control for zones or single rooms, the climatic compensation
function) and by the configuration of the devices (ON / OFF or PI proportional-integral
control). Depending on the value of the index, the radiant system can be placed in 5
classes, from AAA (> 0.98) to D (< 0.88).
Simulations (source: UNI / TR 11619)
As time goes by, more and more projects of buildings are submitted to sustainability
certification. The concept of “sustainability”, which is now common in many sectors,
was defined in the “Our Common Future” report (known also as Brundtland Report)
published in 1987 by the World Commission on Environment and Development.
Sustainable development is a process that ensures “that the needs of the present
generation are met without compromising the ability of future generations to meet
their own needs”. In this sense, sustainability must ensure compatibility between
development and environmental protection.
Buildings are major consumers of resources and therefore this principle also applies
to them; for this reason, certification schemes have been developed over the years to
certify their sustainability. Building projects that are subject to sustainability certification
can receive points in different categories: in the case of LEED* (Leadership in Energy
and Environmental Design), for example, they include location and transport, site, water
efficiency, energy and atmosphere, materials and resources, indoor environmental
quality, innovation and more. Based on the number of credits obtained, a project
obtains one of the levels of assessment provided for in the certification scheme.
Building automation plays a very important role in achieving sustainability certification.
The use of the KNX system can contribute to obtaining up to 54 credits** out of a
maximum of 110 provided for by LEED certification. 80% of the credits to which KNX
contributes relate to three LEED categories: water efficiency, energy and atmosphere,
and indoor environmental quality.
*) Developed by U.S. Green Building Council (USGBC)
**) KNX for LEED, 2013, Jesús Arias García, Miguel Ángel Jiménez Ibiricu, KNX Association cvba (Bruxelles)
In order to better define the concept of sustainability with reference to the construction
sector, the ISO 15392 standard was also published in 2008, which sets out sustainability
objectives and general principles. The standard defines sustainability as “the condition
in which the components of the ecosystem and their functions are maintained for the
present and future generations”. To complete ISO 15392, the technical specification
ISO/TS 12720 has been published, which provides guidelines for its application. In
addition, ISO 21931-1 identifies and describes the factors to be considered when
assessing the environmental performance of new or existing buildings in the design,
construction, operation, maintenance, renovation and decommissioning phases.
References
ISO 15392:2008 Sustainability in building construction - General principles
ISO/TS 12720:2014 Sustainability in buildings and civil engineering works - Guidelines
on the application of the general principles in ISO 15392
ISO 21931-1:2010 Sustainability in building construction - Framework for methods of
assessment of the environmental performance of construction works - Part 1: Buildings.
Sustainability certifi cation
Energy classifi cation of radiant systems (UNI / TR 11619)
Control
Description
ηrg
Only zone
ON / OFF
Thermostat in living room, setpoint temperature: 20°C ± 1°C. Fixed
fl ow temperature equal to the design temperature determined in the
most disadvantaged room.
0,848
(intermediate
situations)
...
da 0,862 a
0,916
For single room,
PID controller
A thermostat in each room (living room, bedrooms, bathroom),
setpoint temperature: 20°C. The digital electronic control unit
controls the electrothermal actuators located on the manifold
valves and the three-way mixing valve. The control unit receives the
temperature data from all the zones in the room..
0,987
Ideal situation
Maintain an internal temperature of 20°C in all rooms..
1,00
HVAC applications - March 2021
The technical information contained in this catalogue is purely indicative. The company reserves the
right to make changes without notice.
The diagrams show some examples of use of the Ekinex® devices developed according the KNX
standard, are made with simplifi ed symbols and report only the system components relevant for
the control and automation with Ekinex® devices. For the design, installation and commissioning of
Ekinex® systems and systems, please contact qualifi ed professionals.
For installation, connection and commissioning of Ekinex® devices refer to the technical documentation.
For availability of Ekinex® products on your market, please contact the Ekinex® sales department
(sales@ekinex.com).
© Ekinex S.p.A. 2021. Reproduction of parts of the catalogue is only possible with the prior written
approval of Ekinex S.p.A.
Credits
Creative Manager
Ekinex® Marketing & Communication
Graphical project
Ekinex® Marketing & Communication
Product design
Tommaso Marchi Architetto
Contents
Ekinex® Business Development
Printing
Tipolitografia Testori Snc
CATHVACEK0321EN
Contacts
Ekinex S.p.A.
Via Novara, 37
I-28010 Vaprio d’Agogna NO - ITALY
T +39 0321 1828980
info@ekinex.com
www.ekinex.com
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