THE INFLUENCE OF THERMAL ZONING on the
THERMAL COMFORT and ENERGY CONSUMPTION in
LOW ENERGY OFFICE BUILDINGS
45th HVAC&R Congress and Exhibition, 3-5 December 2014, Belgrade, Serbia 1
Renewable Energy Systems and Recycling R&D Center
Transilvania University of Brasov, Eroilor 29, 500036 Brasov,
Romania
Macedon MOLDOVAN, Ion VISA, Anca DUTA
GOAL
The improvement of the
thermal comfort
and of the
energy efficiency
in low energy office buildings.
2
Outline
Introduction
Methodology
Case study – The RES‐REC Building of the R&D Institute of the Transilvania University of Brasov
Results and Discussions
Conclusions
3
WHY LOW ENERGY BUILDINGS?
4
1.Energy
2.Water
3.Food
4.Environment
5.Poverty
6.Terrorism & war
7.Disease
8.Education
9.Democracy
10.Population 1996 Nobel Prize laureate
"Top Ten Problems of Humanity for Next 50 Years", Professor Richard Errett Smalley,
Energy & Nanotechnology Conference, Rice University, May 3, 2003
WHY LOW ENERGY BUILDINGS?
5
10,000,000,000 in 2050
6
10,000,000,000 in 2050
WHY LOW ENERGY BUILDINGS?
The new Recast of European Directive 2010/31/EU concerning the Energy Performance
of Buildings (EPBD) Nearly Zero Energy Building mandatory Standard:
'very low energy needs‘ all energy consumption inside the building, related to
heating, cooling, ventilation and lighting
meet those needs 'to a very large extent' by renewable energy,
the renewable energy is 'harvested locally or in close proximity to the building'.
In force for EU member states starting with: 2019 Public buildings
new or existent buildings undergoing major renovation 2021 All buildings
Barriers:
- additional costs for improving the energy efficiency
- additional costs for implementing the renewable energy systems
- space availability for RES implementation
7
WHY LOW ENERGY BUILDINGS?
To obtain a LEB: an integrated design should be applied from the very first steps including:
- passive design principles
- energy savings measures
- energy efficient equipment
Objectives:
- thermal comfort ► improved occupants’ satisfaction/productivity
- reduced energy consumption for heating, cooling and lighting
Thermal zoning:
- represents a viable solution to address above objectives
- through selective/differential heating or cooling.
8
LOW ENERGY BUILDINGS (LEB)
EU BUILDING SECTOR → 40% ENERGY CONSUMPTION AND ASSOCIATED GHG EMMISIONS
NON‐RESIDENTIAL BUILDING REPRESENTS 25% OF BUILDING SECTOR
OUT OF WHICH OFFICES + EDUCATIONAL = 40%
9
WHY OFFICE BUILDINGS?
Because of the willingness of companies to invest to:
- decrease theirs operating costs,
- improve employees’ productivity,
- improve its “green” image,
as an open commitment towards sustainability.
10
WHY OFFICE BUILDINGS?
11
SPECIFIC DESIGN CRITERIA
a) large open offices, with a high ratio of glazed to opaque facades;
b) FUNCTIONAL ZONES in which the office building is divided;
c) floor position on the building height;
d) the daily schedule, the occupancy;
e) air pollution and odour control etc.
WHY OFFICE BUILDINGS?
The paper proposes a novel concept
of THERMAL ZONING.
The concept addresses the second
step of an algorithm* previously
developed in general terms to
improve the renewable energy mix for
a building toward the nZEB status.
* Visa I., Moldovan M.D., Comsit M., Duta A., Improving the renewable energy mix in a building toward the nearly zero energy status, Energy and Buildings, 68, 2014, Pg. 72–78
12
METHODOLOGY
13
THERMAL ZONING shall allow to differently heat/cool any floor of a building or any zone
within a floor or a open space, according to their energy demand. The concept is based on the correlation between the variation in the air temperature
throughout the open office surface and the heating / cooling demand,
Aim: optimizing the design of the hydronic zones and theirs commissioning. Validation: indoor air temperature survey conducted in 2014 for an open office located in an
office building in the new R&D Institute at Transilvania University of Brasov, Romania.
Relevant data were selected and are discussed in the paper, outlining the importance of the
outdoor solar radiation as input parameter, both during the heating and the cooling seasons.
METHODOLOGY
14
CASE STUDY – L7 ICDT
BRASOV
BRASOV
• 500m above the sea level • mountain area • frequent temperature inversions • heating design temperature -21°C • cooling design temperature +27°C
ROMANIA / BRASOV • temperate continental climate • average summer temperature +20°C • average winter temperature -4°C
R&D Institute of the Transilvania University of Brasov
15
• 11 OFFICE BUILDINGS • 9 x 3kW SOLAR THERMA SYSTEMS
• 27 kW PHOTOVOLTAIC SYSTEMS • 2 x 22 kW HEAT PUMPS
• 3 x 300W + 3 x 600W WIND TURBINES
L7
CASE STUDY – L7 ICDT
L7 Building in the R&D Institute Transilvania University of Brasov, Romania, 45°40'08.6"N, 25°32'57.8"E Total surface area: 1350 m2 Status: Low Energy Building
16
CASE STUDY – L7 ICDT
VERTICAL SECTION
THROUGH RES‐REC BUILDING
HORIZONTAL SECTION
THROUGH THE FIRST FLOOR
17
The L7 ‐ RES‐REC Office Building
Indoor Monitoring System
18
35 x EBI‐25 TH SENSORS 3 x EBI 400 IF WIRELESS INTERFACES
Indoor Monitoring System
19
Winlog.web – monitoring software
Outdoor Monitoring System
20
KIPP&ZONEN SOLYS 2 Sun Tracker
Delta‐T weather station
21
Sunny day ‐ heating season – all indoor sensors
RESULTS AND DISCUSSIONS
GH=global horizontal solar radiation, w=wind speed, to=outdoor air temperature, tD=indoor design temperature and ti =indoor temperature sensors
22
GH=global horizontal solar radiation, w=wind speed, to=outdoor air temperature, tD=indoor design temperature and TSE,SW,NW,NE=indoor temperature sensors
RESULTS AND DISCUSSIONS
Sunny day ‐ heating season – only 4 indoor sensors
23
GH=global horizontal solar radiation, w=wind speed, to=outdoor air temperature, tD=indoor design temperature and ti =indoor temperature sensors
RESULTS AND DISCUSSIONS
Cloudy day ‐ heating season – all indoor sensors
24
GH=global horizontal solar radiation, w=wind speed, to=outdoor air temperature, tD=indoor design temperature and ti =indoor temperature sensors
RESULTS AND DISCUSSIONS
Sunny day – cooling season – all indoor sensors
25
GH=global horizontal solar radiation, w=wind speed, to=outdoor air temperature, tD=indoor design temperature and TSE,SW,NW,NE=indoor temperature sensors
RESULTS AND DISCUSSIONS
Sunny day – cooling season – only 4 indoor sensors
26
GH=global horizontal solar radiation, w=wind speed, to=outdoor air temperature, tD=indoor design temperature and ti =indoor temperature sensors
RESULTS AND DISCUSSIONS
Cloudy day – cooling season – all indoor sensors
MODELLING OF:
1. the influence of the solar radiation on the air temperature
distribution in the open space;
2. the influence of the arrangement and commissioning of the
hydronic on the air temperature distribution in the open space;
TO ESTABLISH AN ALGORITHM FOR THERMAL ZONING
FUTURE DEVELOPMENTS
27
Conclusions 1. High indoor temperature differences (up to 8°C) between different peripheral zones
during sunny days, both in the heating and in the cooling seasons !!! ‐ main causes:
‐ large open office with large curtain walls facing South; ‐ heating/cooling evenly distributed over the entire room (usual approach);
‐ consequences ‐ thermal discomfort; ‐ energy looses, especially in heating season through windows opening.
2. Possible actions aiming at increasing the thermal comfort and energy efficiency:
‐ interruption of the thermal energy supply where solar energy contributes to heating; ‐ fine tuning of the thermal energy flow through respective zones.
3. Thermal zoning is necessary:
‐ adequately positioning of the hydronic into the building thermally activated systems, in correlation with the building implementation site, orientation & envelope elements
‐ adequately commissioning of the hydronic in correlation with indoor & outdoor factors
28
Thank you!
Acknowledgement: This paper is supported by the Sectoral Operational Programme Human Resources Development (SOP HRD), financed from the European Social Fund and by the Romanian Government under the project number POSDRU/159/1.5/S/134378.
29
