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

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

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).

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

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

Abstract 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

Abstract 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 which are located inside the cabin with a particular distance

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

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

Abstract 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

Abstract 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

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

(2021). Correction. Science and Technology for the Built Environment: Vol. 27, Thermal Science and Technology, pp. I-I.

Abstract Facility managers of large commercial and institutional buildings periodically collect text-based survey data from their tenants. While these large and amorphous datasets contain valuable information to benchmark operational performance and identify anomalies, it is time and resource-intensive to hire employees to read and analyze the datasets and extract insightful information from them.

Abstract 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

Fixed-bed regenerators (FBRs) are a favourable 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

Lighting control systems have been traditionally employed to reduce energy use for lighting by, for example, maximizing daylight harvesting. When highly efficient light sources are installed and for tasks where maintaining target illuminance is particularly important, designers may decide to prioritize the latter together with energy use. In this context, the use of data-driven algorithms is emerging

The goal of this paper is to quantify the impact of weather-induced and altitude-induced barometric pressure variations on the cooling capacity measurement of hydronic coils in room fan coil units. Based on an AHRI-certified coil simulation model and the Monte Carlo sampling method, capacity measurement data were simulated for three hydronic cooling coils at a fixed testing condition with different

In this study a test procedure for determining capture efficiency (CE) of wall-mounted range hoods, namely ASTM-E3087.18, was used to investigate how the temperature of the simulated cook-top influences CE. ASTM-E3087.18 was initially released in 2017 and revised within one year to modify the temperature requirements of the cook-top from 200 °C to 160 °C; however, there is no evidence of a detailed

Abstract Nowadays with the development of science, many new technologies are being introduced to the fabric membrane material fields. Membrane structures have been widely used in industrial storage buildings to reduce the dust pollution from open storage depots. But the thermal environment of these buildings is poor due to its light weight and low thermal resistance. It is worth exploring appropriate

(2020). IAQVEC: New developments in HVAC design and operation. Science and Technology for the Built Environment: Vol. 26, Papers from IAQVEC 2019, pp. 1351-1351.

Decentralized mechanical ventilation systems had a sustainable growth in the past ten years in order to guarantee air exchange in highly airtight renovated residential buildings. Smart control strategies could provide a solution to the tradeoff between energy efficiency, hygrothermal comfort and indoor air quality. In this paper, a novel fuzzy demand controlled ventilation strategy is proposed, using

In late 2019, ASHRAE hosted the Great Energy Predictor III (GEPIII) machine learning competition on the Kaggle platform. This launch marked the third energy prediction competition from ASHRAE and the first since the mid-1990s. In this updated version, the competitors were provided with over 20 million points of training data from 2,380 energy meters collected for 1,448 buildings from 16 sources. This

In a building-integrated agriculture (BIA) space, peak loads must be estimated to size HVAC equipment in order to maintain indoor air conditions that enhance crop growth. However, the estimation of the rates of heat gain/loss induced by the crops and their impact on heating and cooling loads have only been sparsely addressed. The present study proposes a workflow to estimate the impact of crops on

This paper aims at investigating the performance of some passive techniques integrated to a house in six climates ranging from Cold climate to Desert one. First of all, a case study of a house, located in Marrakech (Hot Semi-Arid climate), is monitored and a TRNSYS-based numerical model is constructed and calibrated using the resulting experimental measurements. Afterwards, thermal behavior as well

(2020). Correction. Science and Technology for the Built Environment: Vol. 26, Papers from IAQVEC 2019, pp. 1509-1515.

Many studies have been conducted to assess the effects of indoor air quality (IAQ) on human health. However, there is still a lack of studies available about the adverse health effects on children’s respiratory health at Child Care Centers (CCC). The aim of this paper was to investigate the risk factors for respiratory symptoms and identify the root cause of IAQ problems at CCCs in Malaysia. The Modified

(2021). Correction. Science and Technology for the Built Environment: Vol. 27, No. 2, pp. I-I.

Monitoring performance of heating, ventilation and air-conditioning (HVAC) during building operation enables to evaluate the appropriateness of the system’s design. Such insights can help to reduce energy consumption while ensuring satisfying indoor conditions in the monitored building. Additionally, such insight can help to improve future HVAC design. The aim of this paper is to present a case study

Trains are an important means of transportation for people to travel. The train's soft sleeper compartment space is relatively small, the density of people is relatively large. Therefore, improving the thermal comfort and air quality of the compartment is of great significance for ensuring a healthy travel environment. To analyze the appropriate mode of conditioned air supply in the train soft sleeper

This paper describes a numerical model that was developed to predict flow and pressure distribution in three multi-branch air duct systems as a function of upstream static gauge pressure. The duct systems were comprised of a combination of wire-wound flexible ducts and rigid sheet metal ducts. The model used the Darcy equation and the concept of the local loss coefficient, in conjunction with the continuity

Airflow measurement is essential to efficiently operate air handling units (AHUs) in commercial buildings. Due to the space and cost limitations for physical meters, many virtual airflow meters have been developed for induction motor driven fan systems. On the other hand, electronically commutated motor (ECM) fans have been widely applied in AHUs. However, the applicability of virtual airflow meters

Programmable thermostats with frequent schedule overrides (i.e., “holds”) are widely assumed to be detrimental to potential energy savings. We explored whether this assumption generalized to a population of smart thermostats using a longitudinal dataset of 20,000 devices from a single manufacturer. We observed a majority of devices were infrequently overridden, most often to less energy-efficient setpoints;

Operating room ventilation is quite important to protect patients from infection risk inside a surgical field. The laminar flow units (LAF) used in these applications contribute to removal of pathogen particles from the operation area by creating a protection zone on the surgical field. In this study, effect of LAF diffuse size on airflow and particle distribution in an operating room is investigated

This work aims to develop two main ideas: first, the use of the artificial neural network (ANN) approach to predict the moisture removal rate (MRR) and the dehumidifier effectiveness (ɛ) of a counter-flow liquid desiccant dehumidifier using calcium chloride as an absorption solution. Second, the Garson method is used to identify the most important working parameters influencing the performance of the

Owing to design and operation limitations, most multi-zone variable air volume (VAV) systems in existing buildings still follow traditional techniques for ventilation. In recent ventilation research, most studies focused on comparing a traditional strategy with a superior one, and the comparison studies among traditional strategies are relatively rare. In this paper, four traditional outdoor airflow

The design of windows can provide the proper lighting of the interior and create comfortable conditions to increase the efficiency of the building. Furthermore, in designing building façade articulation, it is important to consider the projection and indentation, therein. This study aimed to evaluate the optimum parameters of the window by measuring energy consumption and daylight quality in residential

(2020). Toward a user-centered built environment. Science and Technology for the Built Environment: Vol. 26, No. 9, pp. 1163-1164.

Part-load performance models for fans driven by electronically commutated motors in fan-powered terminal units were developed based on the analysis of data from 36 series and parallel units provided by four manufacturers. Fan motors ranged from 0.33 to 1 hp (249 to 746 W) and maximum external static pressures from 0.5 to 0.75 in. w.g. (125 to 188 Pa). Part-load performance was estimated from the intersection

This article investigates the in-tube, superheated, saturated, and subcooled condensation of zeotropic refrigerant mixture R454C. R454C is proposed to replace R404A for commercial refrigeration applications. Quasi-local heat transfer coefficients were measured in a 4.7 mm horizontal tube at mass fluxes ranging from 100 to 500 kg m−2 s−1 at three different saturation conditions (40, 50, and 50 °C).

In order to investigate the impact of water quality on fouling process of enhanced tubes, two continuous fouling tests on eight enhanced tubes (with different internal and external tube geometries) and one plain tube (with a plain inside surface and an enhanced outside surface) were carried out in duration of 98 days, using cooling water with medium and low fouling potential respectively at a water

Combined district heating (DH) systems have at least one base load heat plant and several peak-shaving heat sources, which can be installed in the primary network or in the heating substations. This article studies the combined DH system with peak-shaving gas-fired boilers in heating substations, where the peak boilers can be connected to the heat exchangers in series or parallel mode. We analyze the

An experimental test rig is utilized to measure the effects of the flow configuration and particularly the rib geometry, on the thermal performances of solar air heaters. Since the heat transfer rate within the entry length is relatively high, the implementation of the ribs needs to be justified. Computational fluid dynamics simulations are also conducted to support the experiments and to provide detailed

Accurate performance measurements of equipment in the laboratory requires air mixing to reduce temperature and humidity measurement error. The National Bureau of Standards (NBS), now known as National Institute of Standards and Technology (NIST) conducted in-depth experimental research on the static air mixing devices in the late 1960s, which remains the most comprehensive work in this area. Today

Public attention has been drawn to the commercial restaurant cooking emission since it can cause health and hygiene risks, reduction of the efficiency of the ventilation system, and even fire accidents. The attempt of including the Ultraviolet-C (UVC) lamps with Type I hood has the potential to reduce the grease deposition on the ductwork and pollution in the exhaust by oxidizing the emissions. A method

Thermal adaptation plays crucial role in energy efficient operation of buildings without compromising with human thermal comfort. Elevated air velocity is commonly desired to restore comfort requirements at higher temperatures especially in NV and MM buildings located in tropical countries like India. This article is the systematic field study comprising a total of 4872 responses (1874 from NV buildings

To improve the ventilation and air-conditioning energy efficiency of buildings in hot and dry climates, this paper proposed and experimentally investigated an indirect flash evaporative cooling (IFEC) technology combining plate heat exchanger with ultrasonic atomizer. Compared with traditional indirect evaporative cooling (IEC) technology, working air is humidified to be over-saturated by ultrasonic

In this study, R404A and R452A refrigerants used in refrigeration systems were compared experimentally. The energy performance of the system was investigated for widely used evaporation temperatures (−5, 0, +5 °C) and condenser temperatures (25, 35, 45 °C). It was seen that the coefficient of performance (COP) was higher but the power consumption of the system was lower when using R452A as a substitute

Extremum Seeking Control (ESC) strategies are a class of model-free real-time optimization techniques. Because conventional ESC (CON-ESC) based on the dither-demodulation has relatively slow convergence, various alternative forms of ESC have been proposed to improve the transient performance. The purpose of this study is to compare a recently proposed input-output correlation ESC (IOC-ESC) strategy

Growing number of household refrigerators and freezers also increase the overall energy consumption and number of household refrigerators have grown nearly 3% per year. On the other hand, investigations showed that household refrigerators have a significant technical energy saving potential of up to 30–40%. In this study, a single-phase natural circulation loop is considered as a suction line heat