429 Works

Optimization of Novel Air‐to‐Refrigerant Heat Exchangers for Lower‐GWP Refrigerants in Air‐ Conditioning Systems

James Tancabel, Vikrant Aute & Jiazhen Ling
Air-to-refrigerant heat exchangers (HXs) are fundamental components in HVAC&R systems, and considerable research has focused on reducing the airside thermal resistance, which can exceed 70-90% of the overall resistance. Traditional HX design ideology utilizes secondary heat transfer surfaces (fins) to reduce the airside thermal resistance by increasing the airside heat transfer area. However, fins also have inherent deficiencies such as increased airside pressure drop, material costs, and HX fouling/frosting potential. Recent advancements in simulation tools...

Renewables the frontiers towards low carbon resilience

Prachi Ugle Pimpalkhute
As we are transitioning towards low carbon economy, renewables have become a compelling investment for foraying ahead in shaping global energy sector landscapes. Upfront higher costs are an impending challenge for the global renewable market. Ways and means to channelize and inflow of capital into renewables is of utmost priority. Innovation, co-creation and bonds are some approaches towards creating an equally accessible and allocable renewable energy portfolio with reduced credits risks. Credit risks and policy...

Performance Evaluation of Passive Cooling in a Multi- Zone Apartment Building Based on Natural Ventilation

Essam Elnagar, Alanis Zeoli & Vincent Lemort
In moderate climates, using natural ventilation systems could allow to save up to 60 % of the end energy for ventilation and air conditioning. Natural ventilation systems depend on pressure differences to move fresh air into buildings by wind effect and pressure effect. Night cooling can be achieved either by an increased air change rate. The higher air change rate can be realized by ventilators/ mechanical ventilation systems or by free convection. The main objective...

Analysis of Internal Leakages of Residential Ventilation Units by various test methods

Marie-Teres Moser, Anneli Halfvardsson, Jaroslav Chlup & Heinrich Huber
Internal leakages of bidirectional residential ventilation units (RVU) have a negative impact on hygiene and energy efficiency. Therefore, internal leakages are an essential part of the European standards and should be a requirement and part of the energy labelling in the revision of Regulation EU 1253/2014. The current test standard defines a static pressure method intended for RVUs with plate heat exchangers. In addition, there is an in-duct method and a chamber method, using tracer...

Increasing the Energy Flexibility of Buildings controlled by Model Predictive Control

Christian Karczewski, Tobias Henzler & Konstantinos Stergiaropoulos
The growth of renewable energy sources in the electricity grid and the electrification of heat generation in buildings using heat pumps increase the necessity of flexible consumers who can change their electric load. Operating the building in a flexible way means that the building’s load is adjusted, e.g. to an electricity price. Model Predictive Control (MPC) is seen as a key algorithm in building energy management systems to provide the requested flexibility. In most studies...

Floor heating pre-on/off parameters based on Model Predictive Control feature extrapolation

Ettore Zanetti, Rossella Alesci, Rossano Scoccia & Marcello Aprile
Floor heating systems are typically characterized by a relatively high thermal inertia, thus they react slowly to setpoint changes. When the system turns on, an under-heating period could occur for a relative long period, vice versa when the setpoint is decreased the floor thermal inertia could lead to overheating. In residential applications, the users try to avoid these discomfort problems by using a constant setpoint, higher than the setback. In this way the average energy...

Influence of a portable air cleaner location on the exposure to exhaled contaminants in hospital rooms

José Luis Sánchez-Jiménez & Manuel Ruiz De Adana
Indoor environments with a deficient mechanical ventilation, could increase exposure to exhaled contaminants. This situation is critical in hospital environments such as hospital rooms. In this situation, a portable air cleaner system based on high efficiency air filters maybe a solution by itself or combined with mechanical ventilation systems to reduce the concentration of aerosols in hospital room environments. In this study the influence of the location of a portable air cleaner based on high...

Interoperability as a driver or barrier of smart building technologies?

Stijn Verbeke, Karine Laffont & David Rua
Smart building solutions are a strong leverage for increased energy efficiency in buildings, improved quality of life for occupants and added value for work performance. However, the degree of interoperability of technical building systems (and analysis / software tools that use data from these systems) can be a limiting factor affecting the smart services and impacts that can be delivered within a building since several ways of representing components and systems exist and inherently means...

Review of health and well-being aspects in Green Certification Protocols

Cécile Berquand
. Over the past decades, the world-leading Green Certification Protocols have been paid increasing attention to health-related aspects of buildings. However, the way and the extent to which green certifications currently account for these aspects vary largely. This paper aims to review and compare four certification protocols, namely LEED v4, BREEAM 2018, WELL v2, and MINERGIE-ECO v1.4, and to provide insights on how aspects related to occupants’ health and well-being and their influencing factors are...

Hybrid photovoltaic-thermic system with enhanced cell energy efficiency

Marius Branoaea, Andrei Burlacu, Marina Verdeș, Vasilica Ciocan, Marius Costel Balan & Robert Ștefan Vizitiu
Interest towards green energy has been increasing over the past decades, due to the increasing effect climate change and unsustainable energy sources pose to the planet. Among the renewable energy sources only solar, hydropower and wind provide substantial potential, while geothermal, wave energy, and biomass provide a local solution. Solar energy has the potential of being one of the world’s largest energy providers, due to the fact it is present in every corner of the...

A novel machine learning approach to predict short- term energy load for future low-temperature district heating

Thomas Ohlson Timoudas, Yiyu Ding & Qian Wang
In this work, we develop machine learning methods to forecast the day-ahead heating energy demand of district heating (DH) end-users in hourly resolution, using existing metering data for DH end-users and weather data. The focus of the study is a detailed analysis of the accuracy levels of short-term load prediction methods. In particular, accuracy levels are quantified for Artificial Neural Network (ANN) models with variations in the input parameters. The importance of historical data is...

Comparison of Indoor Pollution using Different Ventilation Methods

Salam Al-Samman, Mahroo Eftekhari, Vanda Dimitriou, Daniel Coakley & Charalampos Angelopoulos
One of the essential aspects of healthy buildings is the air quality that people breathe indoors, as it directly impacts their comfort, health, and well-being. Achieving an acceptable indoor air quality (IAQ) has become an essential design objective for newly constructed and renovated buildings as well as for the operational system in existing buildings. The COVID-19 pandemic, which began in 2019, highlighted the need for better IAQ. The quality of indoor air space is not...

Experimental and CFD comparison of driver's thermal plume with classical air diffusers

Amaury Jamin, Paul Alexandru Danca, Bart Janssens, Florin Bode, Ilinca Nastase & Walter Bosschaerts
In confined spaces, such as vehicle cabins, airflow distribution is one of the most critical factors affecting thermal comfort and pollutant dispersion. To develop innovative and energy-efficient HVAC systems, a deep understanding of the human thermal, supplied air jets separately, and their combined interaction became essential to improve our knowledge of airflow patterns for optimizing ventilation system design, thermal comfort, and, indirectly, energy efficiency. To improve our global knowledge, we have developed a full-scale experimental...

Experimental investigation on a packaged unit of membrane dehumidification-based ventilation system

Cho Hye-Jin, Cheon Seong-Yong, Jo Su-Young, Lee Soo-Jin, Lee Gyu-Bae & Jeong Jae-Weon
This study purposed to experimentally investigate the seasonal operating performance of the packaged unit of a hollow membrane-based ventilation system. The packaged unit of the proposed ventilation system was fabricated, and the experiments was conducted based on the test standards for the energy recovery ventilator addressed from air-conditioning, heating and refrigeration institute (AHRI). In addition, for achieving the optimal heat and moisture recovery from the ventilation system under various operating conditions, the seasonal operation modes...

Effect of measurement resolution on data-based models of thermodynamic behaviour of buildings

Thea Hauge Broholta, Louise Rævdal Lund Christensena & Steffen Petersena
Multiple studies have investigated and shown a theoretical potential in utilising Model Predictive Control (MPC) of residential heating systems to lower CO2-emissions. However, there are several practical issues in realising this potential. This paper reports on a simulation-based study focused on two of these issues both related to the data-based identification of a black-box state-space model for MPC. First, it is investigated how the measurement resolution of the heating energy consumption affects the precision of...

Experimental assessment of thermal effectiveness of a regenerative indirect evaporative cooler

María Jesús Romero-Lara, Francisco Comino & Manuel Ruiz De Adana
Heating, ventilation and air-conditioning, HVAC, systems represent a significant energy use in Europe, around 50% of total energy use in buildings. Conventional HVAC systems are mainly based on direct expansion units, whose use of 100% outdoor air leads to high energy use. Then, different innovative and efficient air-cooling systems could be an interesting alternative to approach Nearly Zero Energy Buildings, nZEB. One of these efficient solutions is the technology of indirect evaporative cooling. This work...

Interoperability of semantically heterogeneous digital twins through Natural Language Processing methods

Alina Cartus, Maximilian Both, Nicolai Maisch, Jochen Müller & Christian Diedrich
Self-organizing systems represent the next stage in the development of automation technology. For being able to interact with each other in an interoperable manner, it requires a uniform digital representation of the system’s components, in the form of digital twins. In addition, the digital twins must be semantically interoperable in order to realize interoperability without the need for costly engineering in advance. For this purpose, the current research approach focuses on a semantically homogeneous language...

Transient analysis of individual return temperatures in hydronic floor heating systems

Simon Thorsteinsson, Henrik Lund Stærmose & Jan Dimon Bendtsen
In this work, we investigate some potential benefits and opportunities gained from monitoring the return temperature of all the circuits in a hydronic floor heating (FH) system. It is for example possible to obtain information on the flow distribution in the FH system. Since flow sensors are relatively expensive, most currently installed FH systems do not provide any information on the flow entering the forward manifold, let alone flows in the individual circuits. This lack...

Nearly Zero Energy Buildings as a Standard of 21st Century – Velux RenovActive

Anna Predajnianska, Eva Švarcová, Imrich Sánka & Dušan Petrás
Most residential buildings in Slovakia, built in the 20th century, do not meet current requirements for energy efficiency. Therefore, nationwide remedial measures have been taken to improve the energy efficiency of these buildings and reduce their energy consumption. That is why Velux has created a RenovActive project to make this possible. The goal of renovations is to ensure today´s strict conditions for the energy consumption of buildings and thus achieve nearly zero energy buildings. In...

Decentralized storage in combined heat distribution circuits: how to control?

Stef Jacobs, Margot De Pauw, Peter Hellinckx & Ivan Verhaert
In apartment buildings, collective heating networks have great energetic advantages. One form gaining more attention for the last decades is a combined heat distribution circuit (CHDC), in Belgium called “combilus”. It is a two-pipe system for the distribution of both space heating (SH) and domestic hot water (DHW). The supply temperature is set to the highest needed temperature, which is around 65°C for DHW (considering a temperature difference for enabling heat transfer). However, if decentralised...

A New Learning Programme to Facilitate nZEB Implementation

Florin Bode, Ilinca Nastase, Mihnea Sandu, Cristiana Croitoru & Horia Petran
The goal of nearly zero-energy can be achieved nowadays with existing technologies and practices, but the concept is still unfamiliar and elusive in most of the European countries, considering the whole process chain, despite all previous initiatives in this direction. At this moment there are still barriers in the value chain, making the nZEB concept difficult to arrive at the final users. The nZEB market analysis at European level reveals a significant gap between the...

conceptualization of exhalation in buildings

Sara Dorregaray-Oyaregui, Arturo Ariño, Leonardo Andrade De Brito, Amaia Zuazua-Ros, Juan Carlos Ramos, Robiel Manzueta, Bruno Sánchez Sáiz-Ezquerra & César Martín-Gómez
Among the sources of urban air pollution, the gases and airborne particles coming out from residential buildings through normal ventilation outlets are often neglected or poorly understood. Yet, it carries the potential to deeply affect urban air quality, given the universal ubiquity and function of dwellings. The climate emergency declaration approved by the European Parliament on November 28th, 2019, calls for urgent science-based action to curtail it. Our research explores the concept of building exhalation,...

Dynamic evaluation method for assessing households’ thermal sensation using parametric statistical analysis

Hasim Altan & Bertug Ozarisoy
Climate change is causing a wide range of impacts, including more frequent and brutal climate events, such as long-term heatwaves while compound effects of extreme weather events can dramatically disrupt indoor thermal conditions, causing increased mortality risks, especially for vulnerable populations with health conditions. Comfort standards do not give clear guidelines to determine the minimum or ideal range of continuous measurements, considering the climate change projections to determine neutral thermal comfort thresholds in 2030s, 2050s...

Potential of WASTE WATER HEAT RECOVERY in reducing the EU's energy need

Pavel Sevela, Johannes Frenger, Jürgen Schnieders & Rainer Pfluger
After extensive research, Waste-Water Heat-Recovery (WWHR) technology was identified as the most promising technology to unlock the under-addressed potential in reducing the energy need for water heating. Particularly interesting application of WWHR is for showering, which accounts for about 70 to 82 % of the daily residential hot water tapping profile. Shower-wise installed heat-exchangers offer a cost-effective way of utilizing otherwise wasted heat for preheating cold fresh water, thus reducing the temperature span covered by...

Intelligent building envelope solutions in Finnish new and old apartment buildings

Azin Velashjerdi Farahani, Juha Jokisalo, Natalia Korhonen, Kirsti Jylhä, Heikki Ihasalo, Jaakko Ketomäki & Risto Kosonen
This study investigated the effects of intelligent building envelope solutions (automated blinds, openable windows, and awnings as well as electrochromic windows) in Finnish old and new apartment buildings. Moreover, the results are compared to the passive solutions (manual blinds and solar protection windows). The main goal was to compare the performance of each solution in improving the indoor temperature conditions in Finland’s current climate. Thus, the solutions were simulated with the usage of a mechanical...

Registration Year

  • 2022
  • 2021

Resource Types

  • Text
  • Book


  • Delft University of Technology
  • Harbin Institute of Technology
  • University of Paris-Est
  • Wuhan Modern Urban Agriculture Planning and Design Institute
  • IHE Delft Institute for Water Education
  • Wuhan University
  • Council for Scientific and Industrial Research