B.W. Olesen

B.W. Olesen
Technical University of Denmark | DTU · Department of Civil Engineering

PhD, Professor

About

191
Publications
76,003
Reads
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5,659
Citations
Citations since 2017
59 Research Items
3330 Citations
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20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600

Publications

Publications (191)
Conference Paper
Full-text available
Personalized Environmental Control Systems (PECS) have advantages of controlling the localized environment at occupants’ workstation by their preference instead of conditioning an entire room. A new IEA EBC Annex (Annex 87 - Energy and Indoor Environmental Quality Performance of Personalised Environmental Control Systems) has recently started to es...
Conference Paper
Full-text available
Personalized Environmental Control Systems (PECS) condition the immediate surroundings of occupants, and they are expected to provide increased comfort, health, and productivity. Studies have reported on their benefits and limitations in addressing individual Indoor Environmental Quality (IEQ) factors, especially in terms of thermal comfort and ind...
Conference Paper
Full-text available
A Personalized Environmental Control System (PECS) aims to condition the immediate surrounding of occupants. This approach is fundamentally different from typical HVAC systems, which aim to create uniform indoor environments, regardless of the occupant preferences. PECS has several advantages including allowing occupants to adjust their immediate s...
Conference Paper
Full-text available
Energy use in building for heating depends on the thermal comfort requirements of the occupants. Personal thermal comfort and clothing behaviours in buildings during winter were studied. The Chinese Thermal Comfort Database contains 41977 sets of data which are from five climatic zones: Severe cold, Cold, Hot Summer and Cold Winter, Hot Summer and...
Article
Full-text available
Published in REHVA Journal Radiant cooling is a promising option for providing thermal comfort with low energy use. The cooling capacity of radiant ceiling panels measured according to standards do not directly represent the cooling provided to the room. An improved measurement method was proposed to improve the prediction of their cooling performa...
Conference Paper
Full-text available
Radiant heating and cooling systems have been proven to be an energy-efficient and resource-effective heating and cooling solution for buildings. One of the key features of radiant systems is the possibility of activating and controlling the thermal mass. This feature allows spreading the heat removal from indoor spaces over a longer period, compar...
Conference Paper
Full-text available
Personalized Environmental Control Systems (PECS) condition the immediate surrounding of occupants in contrast to conventional HVAC systems. PECS have several advantages including allowing occupants to adjust their immediate surroundings according to their preferences, which could improve their satisfaction with the indoor environment, which may le...
Conference Paper
Full-text available
Based on the field measurements and questionnaires surveys carried out in 22 offices in Harbin, China, the group differences (gender, age, BMI, level of education, location groups) in human comfort for different levels of environmental parameters were investigated. It was found that males, elder subjects (above 25 years old) and the subjects with h...
Conference Paper
Full-text available
Personal comfort models could be used for the development of automatic controls for personal environmental comfort systems (PECS). These models often use indoor environment and physiological indicators as attributes for estimating the subjective response of occupants. Traditional indoor thermal environment research and standardization recommend 7-p...
Article
Visual comfort plays a central role in building occupants’ comfort, well-being and productivity. It is therefore fundamental to meet the occupants’ visual and lighting needs, carefully accounting for the room layout, usage and activities. In this framework, physiotherapy centres constitute a peculiar case since they are occupied by therapists and p...
Technical Report
Full-text available
IEA EBC Annex 80 - Dynamic simulation guideline for the performance testing of resilient cooling strategies
Article
Full-text available
The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous i...
Article
Full-text available
International thermal comfort standards are applicable for the design and operation of either mechanically cooled or naturally cooled buildings and limited guidance is given for mixed-mode buildings. In this study, a control framework for mixed-mode buildings was defined based on the adaptive comfort model and PMV-PPD method. The proposed framework...
Conference Paper
Full-text available
Abstract It is possible to use gas-phase air cleaning to improve the indoor air quality and reduce the energy use for ventilation. However, the energy implications of gas-phase air cleaners and the impact on the air quality are not yet quantified. Therefore, by using a dynamic building simulation, the impact of different clean air delivery rates on...
Conference Paper
Full-text available
Abstract No clear guidelines are available for operating mechanical ventilation systems with bypass control in order to maintain the indoor environmental quality (IEQ) levels recommended by standards with the minimum possible energy use. This paper used dynamic computer simulations to study the energy and IEQ implications of multiple mechanical ven...
Article
Phase change materials (PCM) can increase a building’s thermal mass, reducing temperature fluctuations and peaks. However, without active discharge, the PCM’s heat removal capability depends on outdoor temperature fluctuations. The present experimental study investigated the operation and performance of a novel macro-encapsulated PCM panel (MEP) wi...
Conference Paper
Full-text available
In many building regulations, the indoor air quality criteria is specified as an absolute level of CO2 concentration, being also the most common parameter used by demand controlled ventilation systems. The use is however challenged by new research showing that the CO2 as a source itself may influence cognitive performance of people. In the indoor e...
Conference Paper
Full-text available
In this study, a comparison of nine wireless and two conventional wired temperature sensors (all available on the market) was conducted in a climate chamber with a two-person office setup. Measurements were conducted under both radiant and all-air cooling systems, each with two levels of cooling load (33 and 61 W/m2). Sensors were placed in a total...
Article
Thermostats control the heating, ventilation and air-conditioning (HVAC) system of a building based on the temperature they measure. Integration with communication network technologies allows wireless sensors to be used as the temperature sensing component of an HVAC system, increasing the flexibility in the selection and positioning of sensors. Th...
Conference Paper
Full-text available
The number of wireless, low-cost indoor environment sensors is increasing with the improving measurement technology. These sensors could potentially replace the wired sensors integrated in Building Management Systems or could be used to develop a remote, low-cost commissioning process for buildings (without BMS). This study investigated the effect...
Conference Paper
Full-text available
This study assessed metrics available in standards (ISO7730:2006, ASHRAE55:2017, ISO17772:2018, EN16798:2019) and certifications (WELL, BREEAM, LEED, DGNB). A set of measurable IEQ parameters and indicators for short and long-term evaluation were identified. The standards propose certain parameters: operative temperature, CO2 concentration, illumin...
Conference Paper
Full-text available
The effect of indoor environment parameters specified in national and international standards on simulated energy use of an educational spaces were assessed. Standards considered included those of EN, ISO, ASHRAE and ISHRAE. Eight different climatic locations were considered. Energy use to maintain IEQ parameters according to the highest category,...
Conference Paper
Full-text available
There is an increasing interest in evaluating the indoor environment on a yearly basis. The technical report (TR16798-2) to EN16798-1 recommend criteria for thermal comfort evaluation based on heating and cooling seasons, but do not give clear indications of how to manage the transition between them. This study used dynamic simulations to evaluate...
Article
Quality of the indoor environment has become an important parameter to account for in new and existing buildings due to the increasing number of people spending most of their time indoors. Generally, the design and evaluation of indoor environments in buildings rely on appropriate guidelines and recommendations. National and international IEQ stand...
Article
Full-text available
In most countries, PMV is the reference index for the assessment of thermal comfort conditions in mechanically conditioned environments. It is also the basis to settle input values of the operative temperature for heating and cooling load calculations, sizing of equipment, and energy calculations according to EN 16798-1 and 16798-2 Standards. Over...
Article
Full-text available
The common placement of thermostats in offices might not reflect the actual thermal environment around occupants and influence the energy use. In this research, it is questioned which type of thermostat at which location better represents the conditions in the occupied zone and what is the effect on energy use. To answer this, simulations of indoor...
Article
High temperature cooling systems have several benefits, such as their ability to create a comfortable indoor environment in an energy-efficient way. Among these systems, those with high thermal mass such as Phase Change Materials (PCM) in integrated components and Thermally Active Building Systems (TABS) are of particular interest, but it is widely...
Conference Paper
Full-text available
The common placement of thermostats in offices might not reflect the actual thermal environment around occupants and influence the energy use. In this research, it is questioned which type of thermostat at which location better represents the conditions in the occupied zone and what is the effect on energy use. To answer this, simulations of indoor...
Conference Paper
Full-text available
The most commonly used thermostat control variable in heating, ventilating and air-conditioning systems is air temperature. The requirement for thermal comfort in international standards are however based on operative temperature. Will the adoption of operative temperature based control lead to better thermal comfort and how will this affect the en...
Conference Paper
Full-text available
Heat transfer coefficients are often used to describe the thermal behavior of radiant systems and how it transfers heat between the cooled/heated surface and the room. Inconsistency is evident in the values/expressions suggested in literature and standards. This study investigated possible sources of discrepancy in an extensive literature review of...
Conference Paper
Full-text available
Some modern buildings are always designed with large glazing area. Glazing ratio (GR) or window to wall area ratio is an important factor that affects thermal loads. It also has impact on thermal environment because solar radiation through windows and warm/cold window surface temperature in different seasons. In this study, GR of 30% and 100% were...
Conference Paper
Full-text available
Mechanical systems (heating, cooling, and ventilation systems) allow actively controlling the indoor environment in buildings. However, buildings can also be naturally conditioned or conditioned in a hybrid way (benefiting from both natural ventilation and mechanical ventilation in different times of the year or day, also known as mixed-mode). Seve...
Conference Paper
Full-text available
This study reports the main findings from a series of human subject experiments, where the subjects were exposed to the different indoor environments created by different cooling systems. The studied systems were a radiant cooling system (chilled ceiling and mixing ventilation, CCMV), and a combined radiant and convective cooling system (radiant di...
Conference Paper
Full-text available
Heat transfer coefficients are often used to describe the thermal behaviour of radiant systems and how it transfers heat between the cooled/heated surface and the room. In addition to current standards, numerous studies have been conducted to obtain the heat transfer coefficients through experiments and simulations. However, inconsistency is eviden...
Conference Paper
Full-text available
The performance of suspended ceiling panels with phase change materials (PCM) for comfort cooling applications in office rooms was studied. The panel consisted of a metal casing, which encapsulates the PCM. Water can circulate through the pipes embedded in the panel to influence the latent energy storage of the material. To evaluate the performance...
Conference Paper
Full-text available
Two commercially available ceiling panels, one metal and one gypsum incorporating microencapsulated PCM were compared experimentally to determine their limitations and ability to provide an adequate indoor thermal environment. The experiments took place from February to May 2018 in a climate chamber at the Technical university of Denmark. In total,...
Conference Paper
Full-text available
The aim of this study was to determine favorable operation conditions for ceiling panels containing phase change materials (PCM) for cooling applications in office rooms. A recently renovated room in the Technical University of Denmark was used to have realistic boundary conditions. Using TRNSYS 17, the performance of the PCM panels during the cool...
Conference Paper
Full-text available
A model of three PV/T collectors of 3.9 m2 area was developed in TRNSYS for analysing its cooling potential in Athens, Greece; Madrid, Spain; Milan, Italy; Bucharest, Romania; Frankfurt, Germany; Copenhagen, Denmark and Oslo, Norway between 1st of May and 30th of September. An in-depth analysis over the model was conducted for Copenhagen, Denmark w...
Article
Heat transfer coefficients are often used to describe the thermal behavior of radiant systems in buildings and how they transfer heat between their cooled/heated surfaces and the room. In addition to current standards, several studies have been conducted to determine such heat transfer coefficients by means of experiments and simulations. Inconsist...
Article
The most commonly used thermostat control variable in heating, ventilating and air-conditioning systems is air temperature. However, people’s thermal comfort responds to operative temperature more directly than air temperature. Will the adoption of operative temperature based control lead to better thermal comfort and how will this affect the energ...
Article
Wireless indoor environment sensors that can measure temperature, relative humidity and CO2 concentration have recently developed to a stage where they can be used in Building Management Systems (BMS) for building control or could be used to develop a remote commissioning process for buildings without BMS. This provides new opportunities for user i...
Conference Paper
The number of wireless, indoor environment monitoring devices are increasing with the improving measurement technology. This development enables the possibility of deploying many of these sensors in buildings to improve the indoor environment control. Wireless sensors could possibly replace the wired sensors that are integrated in Building Manageme...
Conference Paper
Activating the thermal mass of a building by implementing Thermally Active Building Systems (TABS) assists in reducing energy use for thermal management of buildings by utilizing a low temperature heating and high temperature cooling approach. Coupling TABS with geothermal heat pumps that use low-grade energy source in addition to model-based predi...
Conference Paper
Full-text available
This study investigates the heating operation performance of a multiple-source multiple-use heat pump system, consisting of a sky source heat pump, a ground heat exchanger and floor heating heat pump in an experimental facility named RE (Renewable Energy) House. The novelty of this system is that the ground thermal state is maintained by the combin...
Conference Paper
Full-text available
Radiant heating and cooling (RHC) systems are increasingly applied due to well-known technical advantages such as increased thermal comfort, space saving, and reduced energy use. The building sector is currently one of the largest consumers of fossil fuels; since there has been much concern on the energy use, many directives and legislations have b...
Conference Paper
Full-text available
This study reports the results from an experimental comparison of two cooling systems. The studied systems were a radiant cooling system (radiant ceiling panels and mixing ventilation), and a combined radiant and convective cooling system (combination of a different kind of ceiling panels and diffuse ceiling ventilation). The experiments were condu...
Conference Paper
Full-text available
GEOTABS buildings combine an energy efficient heating and cooling system (Thermally Active Building Systems, TABS) with a renewable energy resource (ground, GEO) to heat and cool buildings in an energy efficient and sustainable way. Within the scope of a new EU project (HORIZON 2020-10 project EE-04-2016), hybrid GEOTABS buildings are studied in d...
Conference Paper
Full-text available
This study examined the effect on energy use and thermal comfort when combining microencapsulated phase change material (PCM) with radiant ceiling panels in a two-person office. The performance of the system was studied during the cooling season in the climates of Copenhagen, Denmark, and Rome, Italy, using a basic cooling strategy and a night cool...
Conference Paper
Full-text available
This study examined the performance of Phase Change Material (PCM) in active ceiling panels under extreme climate conditions. The purpose was to reduce the annual energy use and still maintain an indoor climate corresponding to Category II in the European Standard, EN15251. Dynamic yearly simulations were run with a building simulation software for...
Conference Paper
Full-text available
Radiant heating and cooling systems, and Thermally Active Building Systems (TABS) in particular, have several advantages such as benefiting from the low temperature heating and high temperature cooling principle, coupling with renewable energy sources, peak shifting and peak load reductions. When using TABS, most building simulation models assume a...
Conference Paper
Full-text available
The aim of this study was to examine the performance of phase change material (PCM) in active ceilings for an office room under different Danish building regulations for both heating and cooling purposes. A model of a two-person office room was simulated with the only heating and cooling source being radiant ceiling panels containing PCM. The targe...
Technical Report
Performance evaluation of radiant and convective cooling/heating systems Survey on HVAC related potential research themes for office buildings
Article
Free-hanging horizontal and vertical sound absorbers are commonly used in buildings for room acoustic control; however, when these sound absorbers are used in combination with Thermally Active Building Systems, they will decrease the cooling performance of Thermally Active Building Systems and this will affect the thermal indoor environment in that...
Article
Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing buildings in Nordic countries for greater energy efficiency,...
Conference Paper
Full-text available
PhotoVoltaic/Thermal (PV/T) panels were used for cooling water through the principle of nocturnal radiative cooling. This water was utilised for discharging Phase Change Material (PCM) which was embedded in ceiling panels in a climate chamber. Three different sets of flow rates were examined for the solar and the PCM loops, for five days each. The...
Conference Paper
Air-based and water-based indoor terminal units can be used to heat and cool indoor spaces. The choice of terminal unit has direct effects on occupant thermal comfort, and on system performance through energy and exergy inputs to heating and cooling plants and through energy and exergy inputs to auxiliary components (pumps and fans). Energy and exe...
Conference Paper
Full-text available
A simulation study was conducted to examine the possibility of using PhotoVoltaic/Thermal (PV/T) panels and unglazed solar collectors for producing cold water through night-time radiative cooling. The cold water was used as the medium for cooling an office in three different cities (Copenhagen, Denmark, Milan, Italy and Athens, Greece) during the c...
Conference Paper
Full-text available
The real energy performance of buildings depends both upon deterministic aspects (building's physics and engineering systems) and probabilistic aspects such as weather and occupant behavior. Occupant behavior is usually not directly considered when calculating the expected energy performance of buildings. In fact, field test studies all over the wo...
Article
The possibility of using PhotoVoltaic/Thermal (PV/T) panels for producing cold water through the process of nighttime radiative cooling was examined experimentally. The cold water was used to discharge Phase Change Material (PCM) in ceiling panels in a climatic chamber. Both night-time radiative cooling and night-time ventilation were used as the d...
Conference Paper
Full-text available
Thermally-Active Building Systems (TABS) have proven to be an energy-efficient and economical cooling and heating solution for commercial buildings. However, acoustic comfort is often jeopardized in such buildings, due to the thermal requirements of the system. More knowledge is required to understand to which extent a layer of hanging sound absorb...
Conference Paper
Full-text available
Recently there has been a considerable increase in the use of Thermally-Active Building Systems (TABS) in Europe as an energy-efficient and economical cooling and heating solution for buildings. However, this widespread solution requires large uncovered hard surfaces indoors, which can lead to a degradation of the room acoustic comfort. Therefore,...
Conference Paper
Full-text available
Floor covering resistance (material and thickness) can be influenced by subjective choices (architectural design, interior design, texture, etc.) with significant effects on the performance of a radiant heating and cooling system. To study the effects of floor covering resistance on system performance, a water-based radiant floor heating and coolin...