Abstract In this study, volatile organic compounds (VOC) were measured from 47 hospital rooms to determine the most suitable sampling location for VOCs indoors. Another goal was to find out the most predominant VOCs and their emission per floor area in a hospital environment. Three samples were taken from each room simultaneously, one from the center of the room, one from the floor near the wall, and

The purpose of the article is to study the impact of buildings balconies on the energy consumption and indoor parameters. Using both experimental and numerical approach multiple insights were found. The first part is focused on the analysis of 75 block of flats and the influence of closing the balconies on the energy efficiency. It was found out that most of the apartment’s owners have individually

This paper presents a numerical simulation of a ventilated roof based on a novel plastic support especially designed to reduce the solar heat gains by improving the airflow distribution as compared to a traditional one. In order to evaluate the benefits of the new configuration, a 3 D numerical model was developed allowing for a deep understanding of the airflow distribution inside the ventilated roof

ABSTRACT The effects of two window states (closed or open) on the bedroom environment and on sleep quality were investigated. Twenty-seven subjects (14 males and 13 females, 20-33 years old) without sleep disorders and chronic diseases participated. The subjects slept for two consecutive nights with windows open and two consecutive nights with windows closed in four dormitory rooms adapted for the

ABSTRACT A novel Heat Pump-Photovoltaic/Thermal (HP-PV/T) integrated system designed to meet space heating and cooling, electricity generation, domestic hot water production efficiently is a proposed experimental research study. The heat pump running with two evaporators and two condensers operating as air-water and air-air in the HP-PV/T integrated system has been specifically manufactured. This multi-purpose

Abstract In this research work, results on optimization of parameters related to energy consumption for indoor climate control of a building enclosure are discussed. The analysis is carried out for a building unit maintained at comfort level using Mitsubishi 1.5 ton of refrigeration split air conditioner. A mathematical model based on energy balance and experimental trials were used to compute energy

This study proposes the use of hydrofluoroolefins and organic absorbents mixtures as a working fluid pair in a single-effect absorption refrigeration system. In the refrigeration cycle, the 2,3,3,3-tetrafluoropropylene (R1234yf) is used as a refrigerant, and the triethylene glycol dimethyl ether (DMETrEG) and N-methyl-2-pyrrolidone (NMP) are used as absorbents. The working fluid’s thermophysical properties

Theoretical and experimental studies are carried out on a transcritical CO2 based air-conditioning unit. Two configurations– a system with single-stage expansion (SSE) and a system with two-stage expansion (TSE) have been considered. Detailed numerical models have been developed for both configurations. Results obtained from numerical simulations are compared with experimental results. The performance

The displacer-type pulse tube refrigerator is a kind of Stirling-type pulse tube refrigerator with work recovery. It uses a displacer as a phase shifter and has the advantages of high efficiency and compact structure. One-dimensional numerical simulation of the displacer-type pulse tube refrigerator is performed, and the accuracy of the simulation is experimentally verified. The parametric analyses

Abstract This study provides a review of the current state of knowledge, gaps, and potential value in research on the prevalence of faults in commercial buildings. Two separate efforts were made in this study: (1) we performed a literature review to determine the extent of currently available fault prevalence data for heating, ventilation, and air-conditioning (HVAC) systems, and (2) we conducted dozens

Abstract Domestic hot water production is responsible for a significant part of domestic energy consumption; instantaneous gas heating devices are widely used because they don’t require reservoirs, therefore have a competitive use/consumption ratio compared to other technologies. However, users' perception of comfort is severely affected by sudden changes in temperature outside the desired temperature

Computerized maintenance management systems (CMMSs) of large commercial and institutional buildings archive work order logs. These logs contain invaluable operational performance indices pertaining to occupants and building systems. However, there are barriers to extract and visualize meaningful metrics from CMMSs. This study proposes a three-part framework to facilitate this process. The first part

This study presents the energy savings impact of the Continuous Commissioning® (CC®) version of the Existing Building Commissioning (EBCx) process in 197 projects (592 buildings) since the inception of the process in the early 1990s. These are the results of a comprehensive evaluation of the impact of EBCx projects. The evaluation of the impact of EBCx by building type included 316 education buildings

Shallow bore ground heat exchangers have been investigated in recent years because they have the potential to reduce the initial cost of the ground source heat pump system. Correctly modeling the transient heat transfer between the ground heat exchanger and the surrounding soil is essential for predicting a ground heat exchanger's performance. Simplification of the soil model could increase computation

This study develops an add-on local sweating simulation system to upgrade existing dry thermal manikins to local and sweating thermal manikins. The performance of this system was studied using a dry thermal manikin resembling a human lying on a bed with a ventilated mattress. The system comprises water-repellent porous hollow tubes to discharge water onto a diffusive fabric, as well as a motorized

The persistence of energy savings due to the implementation of Existing-Building Commissioning (EBCx) is an important measure of the benefit of EBCx. This study analyzes the persistence of energy savings achieved from the implementation EBCx in nine buildings from 1997 to 2018. Each is served by a central utility plant (CUP) with metered chilled water (CHW) and heating hot water (HHW). EBCx was initially

Abstract In turbulent flows as in HVAC applications, the fluctuation of air speed can affect the sensation of thermal comfort. This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of air distribution systems on the local draft sensation and thermal discomfort for different ventilation cases using numerical simulations

Residential sector is considered one of the largest consumers of primary energy in the world. The main part of total energy consumption in buildings refers to heating. The study presents a thermodynamic sustainability assessment of different energy sources for residential building heating. The paper presents universal methodology, which can be applied to energy and exergy analysis for all types of

This study investigates the influence of glazing characteristics and shading device configuration on energy use and cost, daylighting performance and visual comfort. A typical patient room from a hospital design in Belgium is used as a baseline scenario and different window design alternatives are explored through parametric modeling. Based on the comparative analysis, the article discusses potential

Abstract Thermal comfort evaluation for vehicle occupants is very complicated due to the transient nature and non-uniformity of the vehicle interior. The thermal sensation of an automobile occupant is affected by the surrounding environment. Furthermore, the existing standard was developed for steady state and controlled conditions and it utilizes three evaluation indices, some of which are not adapted

The effect of thermal discomfort on human well-being and performance was studied in the field office, and an attempt was made to elucidate its psychological mechanism. Thirty participants were recruited to perform subjective evaluations and performance tests under 5 different conditions (25 °C, 27 °C, 29 °C, 31 °C, 33 °C). During the experiment, the air temperature was considered as an independent

Abstract This paper investigates the dynamic behavior of dual vapor compression Refrigeration (VCR) chillers, considering nine ecofriendly refrigerants such as R134a, R32, R1234yf, R1234ze(E), R717, R600, R600a, R290, R410a and compared to R22. Disturbances are introduced to the secondary loop of the VCR as sudden and ramp increases of the inlet cooling and chilled water temperatures and their impact

Abstract The abundance of heat-trapping asphalt and concrete, smog, and heat emitted from buildings and vehicles is one of the major reasons for the prevailing high temperature, air and noise pollution in cities. Incorporation of green wall in buildings is considered to be an effective method to reduce temperature and mitigate environmental pollution. This study investigated and compared the performance

In this study a test procedure for determining capture efficiency (CE) of domestic range hoods, namely ASTM-E3087.18, was used to investigate how changing the exhaust orientation of residential range hoods influences CE. Previous studies on residential range hood CE only utilized vertical discharge orientation and do not strictly adhere to ASTM-E3087.18. Furthermore, many range hoods are installed

The presence of an air-space within a building envelope is known to have a varying contribution to the overall thermal performance of the wall assembly due to the combined effect of convection and radiation in the air cavity. In particular, the thermal resistance of a ventilated air-space can vary significantly depending on multiple environmental and thermo-physical parameters. Although the thermal

Abstract The assessment of thermal comfort for patients admitted in hospitals is a mandatory prerequisite meant to ensure the improved wellbeing and support of healing. Our study focused on postpartum women, a particular category of patients, given that they are healthy individuals admitted in hospitals for a physiologic process. We investigated the indoor thermal comfort of 61 early term postpartum

(2021). Professor Raymond Cohen 1923–2020. Science and Technology for the Built Environment: Vol. 27, No. 4, pp. 391-392.

This paper presents the ASHRAE transport properties model for moist air as a "real-gas mixture" employing a modification of the mixing model of Vesovic and Wakeham. It uses the latest research from the International Association for the Properties of Water and Steam (IAPWS), the International Union of Pure and Applied Chemistry (IUPAC), and the National Institute of Standards and Technology (NIST).

The outdoor seasonal weather conditions can influence the insulation performance of extensive green roof. In addition, the thermal behavior of extensive green roof can be affected by the thickness of its layers including substrate and drainage layer. On the other hand, the replacement of polyethylene modular panel with porous aggregates as drainage layer can affect the water retention capacity of green

An improvement of a formerly proposed CFD-based methodology (base model) for the estimation of water evaporation rate in swimming pools is presented here. This base model achieved satisfactorily on average (10% of relative error) under mixed and natural convection, but it deviated from the experimental measurements significantly (up to 45%) for conditions dominated by forced convection. The enhancement

The construction industry is responsible for 36% of the European Union's greenhouse gas emissions. The main goal of the EU in the last decade has been to boost energy efficiency and expand the use of renewable energy in buildings. Ground-to-air heat exchangers may be a solution to reduce the use of primary energy in buildings from nonrenewable sources. The study in this paper deals with an evaluation

Potential energy savings achievable by using isothermal dehumidification instead of conventional air conditioning systems are modeled on a technology-agnostic basis. First, we use simple thermodynamics to model potential device-level energy savings by dehumidifying isothermally instead of by sub-dew-point cooling. A model for dehumidification demand in a prototypical house is then developed, and the

Abstract Direct ground cooling systems (DGCS) can provide comfort cooling to buildings without the use of any refrigeration-based cooling methods. DGCS is an emerging technology, commonly used for new office buildings in cold climates. This study aims at evaluating the energy-saving possibilities of a DGCS compared to a conventional chiller system for an existing office building. A typical Swedish

Refrigerators are the most energy demanding household devices since they are working 7/24. Improving insulation material is crucial for reducing this demand. One of the promising ways to improve insulation materials is to develop better-blowing agents. In this study, the effects of Liquid Blowing Agent (LBA) and Pentane Blowing Agent (PBA) on whole refrigerator insulation were investigated by experimental

ABSTRACT Hydronic coils are often exposed to non-uniform air velocities due to a series of factors, including tight spacing between a fan and a coil, flow area contraction and expansion, existence of obstructions, abrupt change in airflow direction, or the combination of above factors. Although studies showed non-uniform air velocities could cause performance degradation for direct expansion (DX) cooling

Abstract The film wetted area is a significant factor affecting the heat and mass transfer of liquid desiccant. In this paper, a mathematical model with wetness coefficient of cross-flow energy recovered indirect evaporative cooling (ERIEC) assisted liquid desiccant dehumidifier (LDD) based on finite element method was developed to predict the effect of wetness coefficient on the plate heat exchanger

Chillers play essential roles in the heating, ventilation and air conditioning (HVAC) systems to ensure the required thermal comfort. To reduce the operational risk such as faulty operation or energy waste, it’s essential to develop the robust and effective fault detection and diagnosis (FDD) strategy for the chillers. This paper presents a novel hybrid reference model called multi-region XGBoost model

Chillers play essential roles in the heating, ventilation and air conditioning (HVAC) systems to ensure the required thermal comfort. To reduce the operational risk such as faulty operation or energy waste, it’s essential to develop the robust and effective fault detection and diagnosis (FDD) strategy for the chillers. This paper presents a novel hybrid reference model called multi-region XGBoost model

Abstract The film wetted area is a significant factor affecting the heat and mass transfer of liquid desiccant. In this paper, a mathematical model with wetness coefficient of cross-flow energy recovered indirect evaporative cooling (ERIEC) assisted liquid desiccant dehumidifier (LDD) based on finite element method was developed to predict the effect of wetness coefficient on the plate heat exchanger

In this work, the effect of flow circuitry on the performance of a household freezer with a tube-on-sheet evaporator is investigated. The evaporator used in the freezer is a tube-on-sheet type where the tubes are bent and attached underneath the shelves, as in the serpentine heat exchanger. The evaporator is composed of six shelves that are located inside the cabin with a particular distance between

In the last few years, a significant amount of research has focused on learning and modeling personalized thermal preferences to satisfy individuals in buildings. However, there is a disconnection between personal comfort studies and building thermal control research. The objective of this article is to review research studies that integrate personalized thermal preferences into building control systems

A transient multipole method for short-term simulations of ground heat exchangers (GHEs) is presented. The two-dimensional unsteady heat equation over a GHE cross section is separated into two problems: (i) a transient heat equation with homogeneous boundary conditions, and (ii) a steady-state heat equation with nonhomogeneous boundary conditions. An eigenfunction expansion is proposed for the solution

A new test procedure for determining capture efficiency (CE) of domestic range hoods (ASTM-E3087.18) was used to investigate how the range hood mounting height above a stove influences CE. Previous studies on CE utilized only two heights for a single range hood and a test procedure that did not strictly adhere to ASTM-E3087.18. In the study reported herein, testing was performed in accordance with

This paper concentrates on the issues of daylight optimization in an office building using external shading fins/panels. Vertical shading elements are seen as an important tool of daylight management in buildings, especially when the façade is fully glazed. This enables guiding daylight deep into the room, simultaneously reducing the impact of direct solar radiation. The presented analysis illustrates

Incorporating sufficient daylight is an effective and green design strategy to improve visual comfort, energy-efficiency and sustainable building developments. However, there are more artificial lighting consumption, more cooling load and less visual comfort in internal corridors of most buildings due to the shortage of daylight. In this paper, three methods comprising questionnaire survey, numerical

Fault detection and diagnosis (FDD) in refrigeration systems is of great importance for ensuring better equipment reliability and energy efficiency. Although numerous researches studied FDD algorithms and methodology, there is still a lack of mature commercial software in this field. This study presents a novel hybrid model by introducing particle swarm optimization (PSO) into least squares support

In this paper, we will focus on the retrofit of the ventilation system setup on the premise of reserving the original VAV system. Therefore, a combination of the existing VAV system and the dedicated outdoor air system (VAV-DOAS) is discussed. Here, the VAV system handles the indoor temperature and humidity without outdoor air supply, while the DOAS handles the indoor air quality with full outdoor

Urban design between buildings has a strong impact on people who use outdoor spaces. It is directly linked to the configuration of the street axes, orientation, and canopy ratio. This study investigates the impact of urban geometry between residential buildings in Assiut city, Egypt with a ratio of (H/W) 4 as a common design concept of big complexes, on residences thermal comfort and flats indoor environment

The sub-divided unit (SDU) is the major type of substandard housing in Hong Kong. This study monitored the microclimatic conditions in eight SDUs for 24 h in summer. The mean CO2 concentration (1012 mg/m3) under natural ventilation was much higher than the outdoor level (∼410 mg/m3), suggesting that ventilation was ineffective in most SDUs. The mean predicted mean vote (PMV) was 1.7 (warm), corresponding

Abstract CO2-based demand-controlled ventilation (DCV) has been proved to be energy-efficient by altering ventilation rates according to surrogated indications of CO2 levels in single- and multiple-zone single-path variable air volume (VAV) systems. However, DCV for multiple-zone VAV systems with multiple recirculation paths is still untapped. Multiple-zone VAV systems with series and parallel fan-powered

Bedroom ventilation is crucial for providing good indoor air quality, which may contribute to achieving undisturbed sleep. This study presents a detailed characterization of bedroom carbon dioxide (CO2) profiles and ventilation during the heating season in Denmark. The measurements were made in a naturally ventilated (NV) semi-detached house, equipped with trickle vents on the windows and doors (augmented

Building performance optimization is a powerful technique that assists designers in identifying optimal design solutions. However, occupant-related uncertainty is considered a major challenge that can influence the credibility of the selected optimal design. This paper proposes an occupant-centric method for window and shading design optimization in office buildings that assists designers in evaluating

To respond to new energy efficiency standards and environmentally friendly policies in hot climate regions, it is necessary to develop high-efficiency air conditioners. The environmentally friendly and favorable thermophysical properties of R290 and the high efficiency of rotary compressors have led to the proposal of R290 rotary compressors for use in split-room air conditioners in hot climate regions

Fixed-bed regenerators (FBRs) are a favorable option for energy recovery in building HVAC systems due to their high sensible effectiveness. Unlike other types of energy recovery exchangers, the air temperature at the outlet of FBRs varies with time, which creates challenges when measuring the outlet temperature and effectiveness of FBRs since the actual outlet air temperature will include the transient

Abstract A new test procedure for determining capture efficiency (CE) of domestic range hoods (ASTM-E3087.18) was used to investigate how the range hood mounting height above a stove influences CE. Previous studies on CE utilized only two heights for a single range hood and a test procedure that did not strictly adhere to ASTM-E3087.18. In the study reported herein, testing was performed in accordance

Data-driven simulation models can be used for optimal control and decision making in building systems only if they are developed accurately and reliably. An unsolved issue pertains to the data collected from BEMS that generally contain errors owing to sensors, malfunctioning systems, and other unknown reasons. These anomalies generally occur in a multidimensional space and cannot be easily detected

An aircraft cabin environment is affected by many factors during flights. To investigate the impact of passenger behavior on indoor air quality, three passenger behaviors, adjusting the seatback, turns on the gasper and exhale, were studied separately. An aircraft cabin mockup was used to obtain experimental measurements. The air velocity and contaminant distribution are important considerations in

The objective of this paper is to develop a more efficient control logic via investigations of the dynamic characteristics of a CO2 heat pump for heating vehicles. A transient thermodynamic model was set up using Modelica language, and the PID controller was used for a stable cabin environment. The influence of the discharge pressure and airflow rate on the dynamic characteristics, including the dynamic

(2021). Thermal Science and Technology 2019: New research and technologies in air conditioning and refrigeration. Science and Technology for the Built Environment: Vol. 27, Thermal Science and Technology, pp. 1-1.

Wet cooling towers have high thermal efficiency and are cost-effective industrial cooling units, used in factories, in energy plants, and in the HVAC market. The working principle of the cooling towers is based on cooling of the hot process water with cold atmospheric air via cooling fills and water distribution systems. This study investigates the pressure losses and thermal performance of mechanical