Ceiling Surface Research Articles

General Aviation Pilots’ Capability to Interpret Aviation Weather Displays

Current literature indicates that a lack of weather knowledge and poor product interpretability may be contributing to the high probability of fatalities in general aviation weather-related accidents. Eight hundred and thirty-seven general aviation pilots completed an online aviation weather product interpretation test that asked pilots to apply information gleaned from weather hazard products for fight planning. Participants were divided into five categories of certificate/ratings. A total of 118 questions were divided into five separate tests and randomly distributed to the participants. A series of analyses were conducted to assess the impact of weather product and pilot certification on interpretation scores. Overall, certified private pilots scored significantly lower than certificated commercial pilots, flight instructors, and airline transport pilots. Private with instrument rating pilots scored significantly lower than certificated flight instructors and air transport pilots. Further analysis revealed that pilots scored lowest on ceiling visibility analysis, satellite, station plots, and surface prognostic products. Highest scores were associated with winds aloft, graphical turbulence, and pilot reports. The results have implications for both weather display design and pilot training.

An experimental study of the active cooling performance of a novel radiant ceiling panel containing phase change material (PCM)

Phase change materials (PCMs) 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) with embedded pipes as an active ceiling cooling component compared to commercially available radiant cooling technologies. The results show that if the PCM was fully discharged, the installed heat storage capacity was enough to shift the cooling demand to off-peak hours. The MEP’s specific cooling power during melting was between 5.3 and 27.7 W/m2, with 11.3 W/m2 on average over the active ceiling surface for a water supply temperature and flow rate of 20 °C and 140 kg/h, respectively. Under the same conditions, the MEP performance was close to that of the radiant ceiling panels, providing a thermal environment within Category II of EN16798 for 83% of the occupied time. This is significantly better than was achieved by actively cooled gypsum panels with micro-encapsulated PCM whose pipes were in contact with them but not embedded. With its high volumetric heat storage capacity, the MEP could represent a viable thermally active building component for building refurbishment.

Effects of supply Diffuser Shape on Air Age and Human Comfort in an Office with Displacement Ventilation and Chilled Ceiling System in Hot and Dry climate

In recent years, the need to provide a clean environment in enclosed places has drawn increasing levels of attention due to the spread of epidemics and viruses across the world. Chilled ceilings with displacement ventilation represent promising technology. The combined ventilation system has not yet been used in Iraqi buildings, then it’s a good starting point for study the performance of this system in Iraq-Hilla city climate (hot and dry climate). An office room with a combined ventilation system was simulated using AIRPAK software. Indoor air age, air temperature distribution, CO2 concentration and thermal efficiency were estimated numerically. During the simulation process, the effects of two different supply diffuser shapes (one way rectangular diffuser and semicircle diffuser) were compared to investigated the effect of supply diffuser shape on air age and thermal environment in hot and dry climate (passed on peak summer temperatures in Hilla city). Three tests were performed for each case based on changing the load treated by the chilled ceiling as (25%, 50% and 80%) respect to total cooling load and represented (26, 53, 85W/m2) respectively based on floor area. The temperature of chilled ceiling surface varied as (21.5, 19 and 16°C) and the air supply temperature similarly varied (19, 22, and 24.5 °C) respectively at constant air flowrate of (0.045m3/s). The results of the tests found that the effect of diffuser shape on the local age of air decreased with height, the maximum difference between two cases at the 0.1m level was about 49s while at 2.25m level it was only about 11s. The air exchange efficiency for the CC/DV system using a semicircle diffuser in the predetermined office space was higher by an average of 8.5% as compared with a similar system using a rectangular diffuser; this differential reduced about 3% at each increase in portion of cooling load treated by the chilled ceiling, however.

Generalized Additive Modeling of Building Inertia Thermal Energy Storage for Integration Into Smart Grid Control

The structural mass of a building provides inherent thermal storage capability. Through sector coupling, the building mass can provide additional flexibility to the electric power system, using, for instance, combined heat and power plants or power-to-heat. In this work, a mathematical model of building inertia thermal energy storage (BITES) for integration into optimized smart grid control is introduced. It is shown how necessary model parameters can be obtained using generalized additive modeling (GAM) based on measurable building data. For this purpose, it is demonstrated that the ceiling surface temperature can serve as a proxy for the current state of energy. This allows for real-world implementation using only temperature sensors as additionally required hardware. Compared with linear modeling, GAM enable improved modeling of the nonlinear characteristics and interactions of external factors influencing the storage operation. Two case studies demonstrate the potential of using building storage as part of a virtual power plant (VPP) for optimized smart grid control. In the first case study, BITES is compared with conventionally used hot water tanks, revealing economic benefits for both the VPP and building operator. The second case study investigates the potential for savings in CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emission and grid connection capacity. It shows similar benefits when using BITES compared to using battery storage, without the need for hardware investment. Given the ubiquity of buildings and the recent advances in building control systems, BITES offers great potential as an additional source of flexibility to the low-carbon energy systems of the future.

Technical Report: A New Method for Determining Image Distance for Stand Magnifiers.

Low vision rehabilitation clinicians must sometimes evaluate stand magnifiers to determine their true optical properties. A novel method is described for measuring the image distance of stand magnifiers. We describe a new method for determining the image distance of stand magnifiers, which has some advantages over previously described methods. Diverging light emerging from a stand magnifier is brought to a focus on the ceiling or other flat surface using convex lenses placed on the top of the stand magnifier lens. Knowing the power of this convex lens and the distance from the magnifier lens to the imaging surface, one can calculate the degree to which the emerging light is diverging and, from that, the image distance. Each author evaluated three stand magnifiers using this method and compared our results with each other and with the values for image distance published by the manufacturer. Our method produced measurements that were consistent between three clinicians, with emerging divergence values differing by no more than 0.37 D and image distance differing by 0.6 to 3.1 cm for the three magnifiers evaluated. Our measured values also corresponded favorably with the published image distances listed in the manufacturer's catalog, deviating by a maximum of 3.7 cm and a mean of 1.3 cm. When the manufacturer's image distances were converted to dioptric divergence, our measurements varied by a maximum of 0.48 D and a mean of 0.17 D. Our method provides an expedient and clinically accurate way to evaluate the divergence and image distance of a stand magnifier. Knowing the image distance is valuable by itself, but the divergence of the emerging light is also critical in determining the stand magnifier's enlargement ratio.

Influence of sensible cooling load on indoor air distribution in an office room with ceiling cooling and mixing ventilation

A mixing ventilation system integrated with a ceiling cooling system is a potential advanced heating, ventilation and air conditioning system for modern office buildings with a high sensible cooling load. This paper presents an evaluation of the effect of sensible cooling load on the indoor air distribution in a typical office room with mixing ventilation and ceiling cooling. The vertical distributions of indoor air temperature, air velocity and contaminant (CO2) concentration were evaluated by the vertical air temperature difference, turbulence intensity and contaminant removal effectiveness. The results showed that when the chilled ceiling surface temperature was increased from 15.0°C to 23.0°C and supply air temperature was decreased from 22.0°C to 19.0°C, the average vertical air temperature difference, turbulence intensity and contaminant removal effectiveness were 0.2°C–0.3°C, 27%–32% and 0.53–0.81 as both internal and external sensible cooling loads were 41.5 W/m2. Moreover, these evaluation indices varied slightly as the external sensible cooling load was increased from 41.5 W/m2 to 69.5 W/m2, whereas they varied greatly as the internal sensible cooling load was increased from 41.5 W/m2 to 69.5 W/m2. Hence, the external sensible cooling load could slightly affect the indoor air distribution, whereas the internal sensible cooling load could clearly affect the indoor air distribution in an office room with mixing ventilation and ceiling cooling.

Performance of capillary ceiling cooling panel on ceiling surface temperature and indoor thermal environment

A new experimental methodology is presented to show the effect of water supply temperature, mass flow rate and thermal load distribution on the radiant ceiling capacity and thermal comfort conditions. Computerized fluid dynamics simulated vertical temperatures and velocities profiles were validated by a comparison with experimental results and the difference was within 10%. Uniform surface temperature distribution was achieved in a 45.6 m3 test room installed with capillary ceiling radiant cooling panels by an increase in water temperature and air supply velocity. When the ventilation system was turned off, the mean ceiling surface temperature rose from 16.9 ± 0.4°C to 21.5 ± 0.3°C with a rise in the inlet water temperature to 20.1°C. The temperature difference between the head and ankle of an occupant was 2.0°C, which complies with the Chinese standard, GB/T 18049-2017. At a height of 1–1.5 m, the maximum temperature fluctuation was 2°C in the horizontal direction. When the ventilation system was turned on, with the air supply temperature and velocity at 19.8°C and 1.11 m s−1, the ceiling surface temperature was increased by 0.5°C. The indoor air temperature has a positive correlation with the air supply temperature and internal heat load but a negative correlation with air supply velocity.

Green Roofs as Effective Tools for Improving the Indoor Comfort Levels of Buildings—An Application to a Case Study in Sicily

In the line of pursuing better energy efficiency in human activities that would result in a more sustainable utilization of resources, the building sector plays a relevant role, being responsible for almost 40% of both energy consumption and the release of pollutant substances in the atmosphere. For this purpose, techniques aimed at improving the energy performances of buildings’ envelopes are of paramount importance. Among them, green roofs are becoming increasingly popular due to their capability of reducing the (electric) energy needs for (summer) climatization of buildings, hence also positively affecting the indoor comfort levels for the occupants. Clearly, reliable tools for the modelling of these envelope components are needed, requiring the availability of suitable field data. Starting with the results of a case study designed to estimate how the adoption of green roofs on a Sicilian building could positively affect its energy performance, this paper shows the impact of this technology on indoor comfort and energy consumption, as well as on the reduction of direct and indirect CO2 emissions related to the climatization of the building. Specifically, the ceiling surface temperatures of some rooms located underneath six different types of green roofs were monitored. Subsequently, the obtained data were used as input for one of the most widely used simulation models, i.e., EnergyPlus, to evaluate the indoor comfort levels and the achievable energy demand savings of the building involved. From these field analyses, green roofs were shown to contribute to the mitigation of the indoor air temperatures, thus producing an improvement of the comfort conditions, especially in summer conditions, despite some worsening during transition periods seeming to arise.

Impact of chilled ceiling on indoor air distribution in a room with mixing ventilation

A mixing ventilation (MV) system integrated with a chilled ceiling (CC) cooling system will be a potential advanced heating, ventilation and air conditioning (HVAC) system in the modern buildings. This paper presented an experimental study concerning the effect of CC on the indoor air distribution with MV when the internal and external sensible cooling loads changed. The vertical distributions of indoor air temperature, air velocity and contaminant (CO2) concentration were evaluated by the vertical air temperature difference, turbulence intensity and contaminant removal effectiveness, respectively. The results showed that when chilled ceiling surface temperature ranged from 17.0 °C to 26.0 °C, the average vertical air temperature difference, turbulence intensity and contaminant removal effectiveness were 0.2 °C–0.4 °C, 30%–36% and 0.6–0.84 when both internal and external sensible cooling loads were 41.5 W/m2. Moreover, the ranges of these evaluation indices varied slightly when the internal or external sensible cooling load increased from 41.5 W/m2 to 69.5 W/m2. Hence, the chilled ceiling had a slight impact on the indoor air distribution in a room with mixing ventilation. It is interestingly found that the small vertical air temperature difference coincided with the large turbulence intensity and contaminant removal effectiveness with different internal or external cooling loads.

Thermal investigation on the attics of buginese traditional houses in South Sulawesi

This study aims to investigate the thermal conditions of the attic of traditional Buginese houses in the climate of South Sulawesi. The analysis is carried out based on data surveyed from eight houses. The recorded data includes both attic internal weather data and the measured environmental weather starting at 08.00 to 16.00 Central Indonesia Time (CIT). Measurement results showed high temperature in the attics, ranging from 30.7 °C in the morning to 51.1 °C in the middle of the day. Relative humidity minimum of 17.3% at midday and the highest is 67.1% in the morning. The roofs temperature can reach 67.7 °C before midday. The temperature on the attic floor between 24.9 °C in the morning to 43.0 °C in the middle of the day. The difference in the surface temperature of the attic floor guesses to be an average of 1 °C higher than the ceiling surface. Environmental weather factors have the most dominant influence on attic thermal performance.

Dynamic variation of surface temperatures on the radiant ceiling cooling panel based on the different supply water temperature adjustments

Radiant ceiling cooling panels has been easily integrated with air system to reduce the building energy consumption, yet their surface is prone to condensation, restricting the application of such systems in hot and humid climate. In order to prevent surface condensation of the radiant ceiling panels, the dynamic temperature changes of radiant ceiling panel surface must be fully understood. In this paper, experiments are used to investigate radiant ceiling panel surface temperature changes. Experimental results are used to perform numerical simulations and a SAS (Statistical Analysis System) program via linear regression method, in order to study the effect of supply water temperature adjustments on the dynamic temperature changes of radiant ceiling panel surface. Results show that radiant ceiling panel surface temperatures change exponentially with water supply temperature changes when there is a danger of condensation on the radiant panel surface. When the water supply temperature rises, the surface temperature of the radiant ceiling panel increases, effectively preventing surface condensation occurrence and the variation of the supply water temperature has the greatest influence on the surface temperature of the radiant ceiling panel. When the supply water temperature is lowered, the indoor temperature has the greatest influence on the surface temperature of the radiant ceiling panel.

The dynamic effect of supply water flow regulation on surface temperature changes of radiant ceiling panel for cooling operation

Radiant ceiling cooling panels are limited in applications due to surface condensation. Surface temperature is a key factor affecting condensation problems, and supply water flow regulation is closely related to surface temperature fluctuation. In this paper, the dynamic change of surface temperature in regulating the supply water flow is investigated. It is found that when the chilled water supply is closed, the condensation on the radiant ceiling panel surface can be effectively prevented. Using simulation results and statistical analysis, the three main factors affecting the surface temperature for fixed supply water flow are determined as the average temperature of the non-cooling surface, the indoor air temperature, and the internal surface temperature of the outer window. The contribution rates of these factors are 47.6%, 39.2% and 10.1%, respectively. On the basis of this research, the dynamic changes of surface temperature of radiant ceilings for the closed water supply are simulated and verified, and the results are in agreement with the experimental results.

Design improvement in a stepped solar still based on entropy generation minimization

In this numerical study, an entropy generation analysis is performed to optimize the geometry of a stepped solar still through minimization of irreversibilities. The moist air model is used for the simulation of the double diffusive free convection heat transfer inside the stepped solar still. The governing equations are solved by employing a finite volume technique. The influences of some geometrical and operating parameters, including the number and height of the steps and the temperatures of glass ceiling and water surface, on the flow structure, concentration and temperature fields, and different types of irreversibilities inside the solar still are studied. The computational results show that the active sites for generating the irreversibilities are regions near the evaporation and condensation surfaces inside the solar still. The fluid friction and concentration terms have negligible contributions to the irreversibility generation, and the thermal irreversibility is the dominant term in the solar still. All types of irreversibility are intensified by increasing the number or height of the steps. From the view point of irreversibility minimization, the usage of a stepped solar still with lower operating temperatures is recommended. In a solar still with four steps, the viscous, thermal, and concentration irreversibilities increase about 41.55%, 316.43%, and 316.6%, respectively, as the step height increases in the range of 2–5 cm. The viscous, concentration, and thermal irreversibilities increase about 8.2%, 53.5%, and 1.57%, respectively, by increasing the temperatures of the glass ceiling and water surface from Tg = 44 °C and Tw = 49 °C to Tg = 54 °C and Tw = 59 °C.

Impact of chilled ceiling in a high sensible cooling load room with underfloor air distribution

The use of an underfloor air distribution (UFAD) system integrated with a chilled ceiling (CC) cooling system can provide a potentially advanced heating, ventilation, and air conditioning (HVAC) system with high sensible cooling loads in modern office buildings. In this paper, an experimental study of the impact of CC in a room with a high sensible cooling load with UFAD was performed when the chilled ceiling surface temperature increased from 17.0 to 26.0 °C. The vertical distributions of indoor air temperature, air velocity, and pollutant (CO2) concentration were measured and evaluated by the vertical air temperature difference (VATD), turbulence intensity (TI), and contaminant removal effectiveness (CRE), respectively. The results showed that the average VATD, TI, and CRE were 0.1–0.9 °C, 4–40%, and 0.85–1.19, respectively, when the internal and external sensible cooling loads equal 41.5W/m2. These evaluation indices varied clearly when the internal sensible cooling load increased from 41.5 to 69.5W/m2, whereas they were almost the same when the external sensible cooling load increased from 41.5 to 69.5W/m2. The minimum CRE and air diffusion performance index (ADPI) coincided with the maximum heat removal effectiveness (HRE) under a constant cooling load condition. The results suggest that it is better to balance the energy consumption as well as indoor air quality and thermal comfort in a room with UFAD + CC.

Aerial physical interaction via IDA-PBC

This paper proposes the use of a novel control method based on interconnection and damping assignment–passivity-based control (IDA-PBC) in order to address the aerial physical interaction (APhI) problem for a quadrotor unmanned aerial vehicle (UAV). The apparent physical properties of the quadrotor are reshaped in order to achieve better APhI performances, while ensuring the stability of the interaction through passivity preservation. The robustness of the IDA-PBC method with respect to sensor noise is also analyzed. The direct measurement of the external wrench, needed to implement the control method, is compared with the use of a nonlinear Lyapunov-based wrench observer and advantages/disadvantages of both methods are discussed. The validity and practicability of the proposed APhI method is evaluated through experiments, where for the first time in the literature, a lightweight all-in-one low-cost force/torque (F/T) sensor is used onboard of a quadrotor. Two main scenarios are shown: a quadrotor responding to external disturbances while hovering (physical human–quadrotor interaction), and the same quadrotor sliding with a rigid tool along an uneven ceiling surface (inspection/painting-like task).

Measurement and Operational Improvement in an Office with Thermo Active Building System

Thermo Active Building System (TABS) is applied in office buildings in many European countries as a promising energy-efficient solution with a comfortable thermal environment. However, TABS is rarely applied in Japanese buildings because of the risk of dew condensation during the hot and humid summer season. In this study, the indoor environment and thermal sensation in an office building equipped with TABS was investigated; the building is located in an urban area in Tokyo, Japan. Soon after occupancy, field measurements and questionnaire surveys were conducted during the summer and winter seasons for two consecutive years. The operation of TABS was improved based on first-year measurement results. As a result, the ceiling surface setpoint temperature was relaxed, maintaining high satisfaction in summer. In winter, it was confirmed that the operation of TABS was not necessary, and, as a result, satisfaction improved.

Evaluation of Thermal Behavior of the Skeleton in a Green Building with the Aid of TABS

In this study, an office building in Japan that incorporates energy-saving features and environmental technologies was investigated. This office building features a green façade, natural ventilation, a concrete slab with no suspended ceilings, and thermo-active building systems. Two airconditioning systems were installed in this building—a ceiling radiation air-conditioning system and a whole floor-blow off air conditioning system. In addition, a natural ventilation system was installed. We surveyed the heat flux of the ceiling surface and indoor thermal environment of this building from 2015 through 2016. The ceiling using the heat storage amount of concrete maintains a constant temperature in the workplace during as well as after office hours. We also performed detailed measurements of the heat flux of the ceiling surface and indoor thermal environment in the summer of 2017. The results showed that the ceiling radiation air-conditioning system provided a stable thermal environment. Furthermore, we report that making use of the thermal behavior of the skeleton improved the operation of the ceiling radiation airconditioning system.

Enhancement of cooling capacity through open-type installation of cooling radiant ceiling panel systems

Cooling radiant ceiling panel (CRCP) systems have been increasingly applied to modern buildings, owing to high thermal comfort, energy-saving potential, and integration with building design. Currently, the cooling capacity of CRCP is generally evaluated for the closed-type CRCP, wherein the overall ceiling surface is covered with ceiling panels. However, there have been few previous studies on the evaluation of the cooling capacity for open-type CRCP, which are installed with openings (void areas) between adjacent ceiling panels. This study was conducted to verify the hypothesis that the open-type CRCP can enhance cooling capacity by utilizing the cooled plenum air moving through the opening. If the plenum air is cooled by the upper surface of ceiling panels and descends to the conditioned space, it can contribute to increasing the convective heat transfer and cooling capacity. A simulation model for open-type CRCP was developed and validated against the mock-up experiment. Using the simulation model, the cooling capacity of the open-type CRCP was evaluated with respect to the opening area and panel layout. The results showed that the open-type CRCP could provide 54–80% (average 64%) higher nominal cooling capacity than conventional closed-type CRCP. The enhanced cooling capacity may lead to reduction in construction costs and energy consumption, because panel installation area could be reduced and the water temperature can be increased to provide the required cooling capacity. The results of this study would be able to offer fundamental data about cooling capacity of open-type CRCP.

A Study on the Immateriality at the Ryue Nishizawa’s Works

As a result of examining the immaterial expression characteristics of Ryue Nishizawa’s work, the following conclusions were reached within the scope of this study. 1. In Nishizawa s work, immaterial expressions appeared in terms of material aspect, morphological aspect, and spatial aspect. In terms of material, the transparency of glass and the metaphor by white color appeared, and in the morphological aspect, the dynamic form of beyond-gravity of the scalpel appeared. Finally, in terms of space, beyond-boundary characteristics appeared in the interior space, between the interior space and the outer space, and between the outer space and the outer space around the earth. 2. The characteristics of the material aspect and the characteristics of the morphological aspect eventually play a role of the composition and background elements that form the characteristics of the spatial aspect. 3. Such immaterial expressions can be divided into three types according to the expression type. First, in the case of the same type as the one-room type, expressions that acquire beyond-bounding in the internal space due to the transparency of the glass wall appear in the material aspect. Secondly, the separated scalpel and the connection space are separated into several pieces, and the de-bounding between the inner and outer spaces appears due to the transparency of the glass wall in the other mouths that exist in the large outer wall. The third is in the form of a single individual inserted into the atmosphere of the surrounding environment, where beyond-gravity is mainly seen in the morphological aspect. Consequently, the glass wall-a functional boundary inside-disappears and the curved ceiling or floor surface based on the terrain is formed, and the beyond-borderline is found between interior spaces, between interor and exterior spaces and between exterior spaces(in the site, out of the site). 4. Immaterial expression characteristics tend to change from indirect method by material side of the component to direct method of morphological aspect of the building scalpel. 5. He has been working on landscape expression to provide the possibility of a relationship that can be held in free and diverse spaces through the above immaterial expression method and to create an architectural space in harmony with the terrain and surrounding environment.

Influence of Similarity Law on Movement Characteristics of Vibration Actuator

Currently, a belt conveyor or an automatic guided vehicle is used as a conveying device in a factory. However, Transportation of the ceiling surface and the wall surface in these devices is impossible. Elevator is used for conveying from the lower floor to the upper floor. Therefore, the conveying device capable of movement on a wall and a ceiling significantly improves the efficiency of work. Based on this background, development of working robots capable of transporting on a wall surface is required. In the present study, the vibration actuator with a very simple structure capable of movement on a magnetic substance by means of the inertial force of a vibration model was again considered. Furthermore, upsizing for the actuator in order to improve the propulsion characteristics was considered. The volume of the permanent magnet constituting the vibration component of the actuator was increased according to the similarity rule. Four models of actuator with approximately equal drive frequency were prototyped and experimentally tested. The experimental results demonstrate that the maximum efficiency of the actuator for a standard model pulling its own weight was 27.1 %. Furthermore, the actuator is able to pull a load mass of 170 g. For the actuator of 5 times model, the actuator is able to climb upward at 9.5 mm/s while pulling a load mass of 3500 g. This actuator is able to propel a load mass of approximately 36 times the weight of the actuator itself.