Ceiling Panel Research Articles

Classification of radiant and convection time series for cooling load calculation of radiant cooling systems

Radiant cooling systems have the potential for energy saving, better thermal comfort, and space-saving. The lack of cooling load calculation methods limits the engineering application of radiant cooling systems. A universal radiant and convection time series (RCTS) set is indispensable in radiant cooling system design. In this study, an RCTS dataset with 100,000 sample rooms is generated based on the combinations of 9 room characteristic parameters. Extreme gradient boosting (XGBoost) is used to grade the room characteristic parameters and classify RCTSs. Gaussian mixture model (GMM) is used to extract the representative RCTSs for each category. The RMSE is used to measure the accuracy of the representative RCTS. The results indicate that XGBoost and GMM perform very well. Non-solar radiant time series (RTS), convection time series (CTS), solar RTS for radiant ceiling panel systems and solar RTS for radiant floor cooling systems are classified into 12, 8 and 1 categories, respectively. The representative RCTSs of all categories constitute a universal RCTS set. Fifteen room characteristic parameters are taken into account to construct sample rooms for Changsha. The accuracy of the representative RCTS was compared with the self-RCTS and heat balance method. The relative deviations of the design cooling load calculated using the representative RCTS and self-RCTSs were within ±3 % for 90 % cases of the sample rooms. The relative deviations between the design cooling load calculated using the representative RCTS, self-RCTSs, and theoretical design cooling load are within ±7 % for 90 % cases. The universal RCTSs set is applied for radiant cooling systems design.

Investigation on the mechanical properties of wood-plastic composites for the application of ceiling panels

Wood-plastic composites are relatively novel composite materials that consist of a blend of wood flour waste with high-density polyethylene and polypropylene plastic waste, designed for use in ceiling applications. Various samples were produced using different ratios from the total weight, including 20:80, 30:70, and 40:60, with sieve sizes of 0.425 mm, 1.18 mm, and 2 mm. The composites were created by melting plastics and sawdust at a temperature of 1800c utilizing the hot-press moldings technique employing diverse formulations. The properties of sample composites were analyzed experimentally based on ASTM standards to investigate water absorption levels as well as flexural strength, impact resistance hardness along with surface morphology via the design of experiments. This research study indicates that nine composite formulations consisting of HDPE and PP plastics combined with wood flour can produce favorable physio-mechanical properties. Among these various combination specimens tested in this study FS3/FC30N exhibited excellent physio-mechanical properties; including desirable values such as water absorption level at 5.5103%, flexural strength at 61.12 Mpa, impact resistance measuring 33.45 J cm−2, and hardness rating up to 80 RHB. Thus it is highly recommended for use in chipboard ceiling panel applications due to its potential benefits.

Development and thermal performance testing of radiant conditioning ceiling panels

The past decades have seen an advancement from heavyweight radiant floors to lightweight conditioning ceiling systems. However, the performance of these lightweight systems are seldom comprehensively discussed in an informative manner for designers. This paper reviews lightweight radiant ceiling panel designs and conducts instrumental experiments to examine the thermal performance of different designs. Four distinct capillary hydronic panels have been designed and developed to assesses their thermal performance via empirical testing and measurement. Prototypes were built and integrated into a suspended ceiling system where they were tested in cooling mode. The response time, surface temperature, and energy transfer of the different panel designs were investigated. The experiment results show that higher thermal mass yields higher heat transfer and better surface temperature, but longer response time. A better thermal connection between the capillary tubes and the radiant surface also results in better conduction, faster response times, and improved surface temperature.

Experimental and Theoretical Study of Heat Transfer in a Chilled Ceiling System

Radiant cooling has been growing in recent years due to energy savings and improved comfort and health. The aim of this study was to reduce energy consumption and provide comfort using a chilled ceiling panel in the zone. In the experimental part of this study, a test room was created to investigate the change in the heat transfer performance of a chilled ceiling panel according to different water temperatures, different water flow rates and different heat source values. As a result of the experimental study, it was found that optimum conditions were achieved with a heat rate of 280 Watts and the lowest supply water temperature of 14 °C, with indoor comfort conditions being achieved with water flow rates of 0.93 m3/h. In the theoretical part of this study, a thermal balance was established for ceiling panel cooling applications. An analytical model of the heat transfer between the cold ceiling panel and the room air was also developed. The convection coefficient, convective heat transfer and total heat transfer coefficient were compared using the values obtained from the experiments and those reported in the literature. It was found that the convection coefficient was within the range reported in the literature, and the radiation heat coefficient was within 99.8% of the literature values.

Experimental study to understand the thermal environment of an office cooled by radiant ceiling panels and dedicated outdoor air system

This research aims to better understand the radiant environment of an interior space located in the tropical climate that is cooled by Radiant Ceiling Panels (RCPs). To do so, we have designed a highly instrumented 177m2 office testbed in Singapore installed with RCPs, Dedicated Outdoor Air System (DOAS) and Fan Coil Units (FCUs). An 11-day experiment is designed to monitor the radiant environment when being cooled by 1) RCPs + DOAS and 2) FCUs + DOAS with a fixed internal load of 2kW and humidity load of 8g/hr. We alternate between these two cooling modes, with variations in panels’ water supply temperature and window blinds. We expect to see a separation of Mean Radiant Temperature (MRT) and air temperature in mode 1 with the use of improved radiant sensors. However, results showed only minor differences in the radiant environment between the two modes of cooling. There was no significant MRT and air temperature separation (<1°C). These insights provide a better understanding of our radiant environment, which can potentially improve the way we control radiant systems. With better understanding, we can support high thermal comfort performance of a radiant systems as compared to a more common air-based system.

Thermoelectric-Based Radiant Cooling Systems: An Experimental and Numerical Investigation of Thermal Comfort

Researching novel cooling and heating technologies as alternatives to conventional vapor-compression refrigeration cycles has received growing attention in recent years. Thermoelectric (TE) systems rank among promising emerging technologies within this category. This paper presents a comprehensive investigation, utilizing numerical modeling and analysis via COMSOL Multiphysics along with experimental validation, to evaluate the performance of a radiant cooling ceiling panel working on thermoelectric principles. Performance metrics are based on thermal comfort levels within the designed test chamber. The system comprises a rectangular test chamber (~1.2 m × 1.2 m × 1.5 m) with a centrally positioned ceiling panel (dimensions: 0.6 m × 0.6 m × 0.002 m). Four TE modules are attached on top of the ceiling panel, facilitating effective cooling to regulate the ceiling temperature to the desired setpoint. The resultant lower ceiling temperature enables heat exchange within the chamber environment via radiation and convection mechanisms. This study examines the time-dependent variations in mean radiant temperature and operative temperature under natural convection conditions, with comfort level assessment carried out using the PMV method according to ASHRAE Standard 55. An experimental chamber is built to validate the numerical model by performing experiments at various ceiling temperatures. Design challenges are discussed in detail. The results of this investigation offer valuable insights into the anticipated thermal comfort achievable through TE-based radiant cooling systems across various operating conditions.

Classroom acoustics: A case study of the cost-benefit of retrofitted interventions

It is known that suitable classroom acoustics is important for effective teaching and learning. To this end, many countries have developed classroom acoustics standards. However, research shows that these standards are often not implemented. Research assessing the implementation of classroom acoustic standards internationally concludes that successful implementation is driven by mandatory standards that are part of the building codes and that the cost of compliance is a barrier. The study presented here explores the cost of upgrading classrooms to achieve a suitable reverberation time. The paper presents a case study in South Africa, where acoustic standards are generally not implemented and cost and know-how are barriers. The objective was to optimize the cost, acoustic benefit, and accessibility of acoustic interventions. Four adjacent similar classrooms were retrofitted with different sound-absorbing ceiling panels that cover a percentage of the ceiling area. The weighted sum model was used to assess the suitability of each intervention, taking into account the cost, acoustic benefit (in terms of reverberation time), and ease of access to materials. The case study demonstrates that a noticeable improvement in acoustic conditions can be achieved without significant cost and provides a basis for further research to develop simple standardized design recommendations.

A novel cooling capacity prediction model for open-type cooling radiant ceiling

Open-type cooling radiant ceiling panel systems (O-CRCP) have a higher cooling capacity, but their cooling capacity can only be calculated roughly according to the model of the closed-type cooling radiant ceiling panel systems (C-CRCP), which may cause economic and energy waste. This study aims to develop a novel cooling capacity prediction model for O-CRCP considering the impact of panel size, layout, and installation position. The experimental results revealed that the heat flux of the O-CRCP was 49%–64% greater than that of the C-CRCP. A detailed analysis of the simulation results shows that the natural convective heat transfer is the main factor for the cooling capacity enhancement which basically determines the trend of the total heat flux varying with various factors. Based on the simulation results, a novel cooling capacity prediction model for O-CRCP was developed using a multi-regression method. It was evaluated in an actual room with O-CRCP, and the predicted cooling capacity curve showed good agreement with the measured values, the relative error ranged from 5.78% to 9.72% with an average of 7.47%, which is acceptable for engineering applications. The proposed model can provide support and guidance for designers and engineers in selecting and arranging O-CRCP in real applications.

Fabrication and Analysis of Thermal Insulation Ceiling Panel from Corn Husk Fiber

Every year, the Philippines experiences hot and rainy weather. For those who choose to remain at home, summer feels like torture. So, Filipinos have no choice but to turn on their air-conditioning system, which can cause their electricity bill to skyrocket. Corn husk fibers, being a waste product, have great potential to be applied in home textiles, home furnishing, carpet, rugs, and packaging of food grains and crops. The researchers thought of making thermal insulation ceiling panels made of corn husk fibers. The study yielded a result of 0.119 W/m.K for thermal conductivity using a calibrated hot box, below the 0.25 W/m.K maximum threshold for thermal conductivity value. Furthermore, its fire resistance characteristic made it less susceptible to small fire attacks. It was also found that the insulator has 2.19% and 8.42% water absorption values for short and long-term soaking, which is less than the 40% range value for water absorption. Hence, it can be said that it is an excellent thermal insulator.

Fire Ignition and Propagation in Hidden Zones of Aircrafts: A Novel Confined Fire Apparatus (CFA) for Flame Spreading Investigation

This research investigated potential fire hazards originating in hidden areas of pressurized sections of aircrafts. The objective was to establish a laboratory-scale flammability test method to predict the behavior of fire propagation under real fire conditions. A confined fire apparatus (CFA) was designed and constructed, and several tests were conducted to better understand the involved mechanisms and their consequences and to estimate flame spreading in hidden-zone fires. The experimental facility and flame-spreading results obtained for a typical material involved in hidden fires, specifically a ceiling panel, were presented and discussed. The experimental facility consisted of a narrow passage where a fire was initiated using a burner on a specimen exposed to a controlled heat flux. Experiments were conducted in the absence of forced airflow. Flame spreading was estimated through visual monitoring of fire development or temperature measurements at specific locations in the specimen. Both methods yielded similar results. The flame spread velocity in relation to the imposed heat flux allowed for the estimation of the critical heat flux for spreading q˙sp,cr″ and for ignition q˙ig,cr″; the corresponding temperatures, Ts,min and Tig; and the flame spread parameter Φ.

Low-energy resilient cooling through geothermal heat dissipation and latent heat storage

Conventional passive cooling techniques provide limited benefits in extremely hot climates in southern Asia, characterised by high daytime and night temperatures and frequent climate-related disruptions, such as power cuts. This study proposes and demonstrates a novel low-energy and resilient cooling solution for extremely hot regions in southern Asia. The novelty lies in the combination of geothermal heat dissipation and latent heat storage, specifically designed for the particular conditions of extremely hot climates in Southern Asia; considering the influence of climate-related disruptions such as power cuts, whose frequency is increasing in the region; and using discomfort hours as an indicator to measure the passive survivability of buildings in the absence of air-conditioning (following the adaptive comfort model). A numerical model was developed in TRNSYS for optimal sizing and configuration of the phase change material (PCM) integrated into a ceiling panel using a typical multi-family building archetype in three climatic regions of Pakistan. A parametric numerical analysis was performed concerning different PCM melting temperatures, amount of PCM, convective heat transfer capacity, and equivalent thermal conductivity. Moreover, daytime was considered the period with a higher probability of power cuts. The results showed how integrating PCM-based ceiling panels with geothermal heat dissipation can mitigate discomfort hours by 28 % in extremely hot climates, 55 % in very hot climates, and 91 % in hot climate areas with intermittent access to electricity. Latent heat storage maximised the benefits of geothermal heat dissipation by extending thermal comfort periods by 13 % and 18 % in extremely hot and very hot climates compared to the scenario without PCM. This low-energy resilient cooling solution, integrating PCM as a cool battery, can keep the home cool for longer when electricity is unavailable. This study demonstrates the importance of considering the specific climate-related disruptions from these extremely hot regions in building design, such as extreme heat events or power cuts, to enhance the heat resilience capacity of cities.

A family of adverse pressure gradient turbulent boundary layers with upstream favourable pressure gradients

A flat-plate turbulent boundary layer (TBL) is experimentally subjected to a family of 22 favourable–adverse pressure gradients (FAPGs) using a ceiling panel of variable convex curvature. We define FAPGs as a sequence of streamwise pressure gradients in the order of favourable followed by adverse, similar in sequence to the pressure gradients over the suction side of an airfoil. For the strongest pressure gradient case, the acceleration parameter, $K$ , varied spatially from $6 \times 10^{-6}$ to $- 4.8 \times 10^{-6}$ . The adverse pressure gradient (APG) region of this configuration is studied using particle image velocimetry in the streamwise–wall-normal plane. The statistics of the APG TBL show that the upstream favourable pressure gradient (FPG) exerts a strong and lasting downstream influence, and that the rapid spatial changes in the pressure gradients imposed cause an internal boundary layer to grow within the TBL for 15 of the cases studied. The internal layer typically occupies 20 $\%$ of the boundary layer thickness and dominates the boundary layer response, containing the peak turbulent production, peak strength and population of vortices, and most of the spectral energy content of the flow. The outer layer, on the other hand, develops in the APG region without considerable changes to the state dictated by the upstream FPG. These trends are in contrast to APG TBLs that originate from a zero pressure gradient region, where the outer/wake region is known to dominate TBL response. The observed changes are quantified across the family of FAPGs imposed.

Thermal and energy performance evaluation of a full-scale test cabin equipped with PCM embedded radiant chilled ceiling

The escalating global demand for space cooling has led to the emergence of new cooling technologies, including the phase change material embedded radiant chilled ceiling (PCM-RCC) system. This technology improves energy efficiency and indoor environmental quality, while also offering demand-side flexibility. The present study experimentally evaluates the thermal efficiency and energy performance of a PCM-RCC system in a full-scale test cabin equipped with PCM panels. Here, the transient thermal behaviour of PCM ceiling panels besides the cooling energy delivered during charging-discharging cycles are examined. The indoor thermal comfort and peak electricity demand reduction enabled by the present PCM-RCC are also discussed. The results reveal that chilled water circulation for 4–5 h overnight was sufficient to fully recharge the PCM panels. Over 80% of the occupancy time was classified as “Class B″ thermal comfort according to ISO 7730. The system's daily electricity usage was mostly concentrated during off-peak hours, accounting for ∼70% of the total usage. While the controlling schedule used in this study responded to the transient thermal behaviour of the indoor space and PCM ceiling panels, a more dynamic, predictive schedule is necessary to improve the system's overall efficiency and further enhance indoor thermal comfort in response to the changing environmental conditions.

PCM-based ceiling panels for passive cooling in buildings: A CFD modelling

To relieve the upsurge of the energy demand associated to building indoor cooling, passive cooling employing phase change materials (PCMs) has been proposed as a promising technique to stabilise indoor air temperature fluctuation and reduce building energy demand. PCMs can exchange a large amount of latent heat during the melting and solidification processes, which can be utilised in line with the discharging and charging processes of a cooling system. The use of encapsulated PCM ceiling panels in buildings has immense application potential for passive cooling, which has attracted investigations in recent years. The geometry selection of the PCM ceiling panel is vital as it determines the exposed surface area to the surrounding air and the natural convection, and therefore the heat transfer rate to/from the PCM, which generally suffers from low thermal conductivity. This paper builds on the geometric optimisation of enclosed PCM capsules driven by natural convection, aiming to investigate the phase change behaviour and thermal performance of encapsulated PCM ceiling panels of different geometries. Here, the presented study focuses on the conjugate heat transfer phenomena through the surrounding air, panel shell, and PCM. A mixture of lauric, capric, and oleic acids was selected as PCM encapsulated in a thin-shell enclosure made of acrylonitrile butadiene styrene plastic, which forms the aesthetic panels attached to the ceiling. A computational fluid dynamics model was validated using full-scale experimental data and further employed to analyse the discharging process and design considerations of the PCM ceiling panels. The effects of various influencing factors were explored, such as panel volume, the initial temperature difference between PCMs and surrounding air, shell thickness, and geometrical features. The results indicate that the panel comprised of a pyramid array is more advantageous than the tetrahedral-based panel in terms of thermal performance, where the average melting rate is 20.8 % higher when the panel volume is 250 mL. In addition, tweaking the geometric features of the panel will largely impact its thermal performance as the effective heat transfer area and natural convection conditions are varied. Finally, it was found that hanging the panel to the ceiling will effectively enhance the heat transfer compared to directly attaching it to the ceiling. The results complement the knowledge body of macro-encapsulated PCM ceiling panels in terms of thermal performance and geometric optimisation. The effects of geometric features on the thermal performance of the PCM ceiling panels are studied in a more holistic manner.

Field studies on the energy consumption and thermal comfort of a nZEB using radiant ceiling panel and open-loop groundwater heat pump system in a cold region

Field studies were conducted in an office building in a cold region equipped with a radiant ceiling panel (RCP) and open-loop groundwater heat pump (GWHP) system. First, the indoor thermal comfort in a target office was evaluated based on the results obtained from the physical measurements and survey questionnaire. The results showed that the suspended RCP system could achieve comfortable indoor thermal conditions throughout the year. The indoor temperature was maintained within the range of 22–26 °C, the humidity was within 30–60%, and CO2 concentration was mostly below 1000 ppm. Second, the energy performance was tested simultaneously, and intermittent and continuous operation methods were compared. Under the continuous operation method, a stable indoor environment was maintained, and the COP of the GWHP system increased by 10%. The results showed the potential to further reduce energy consumption and maintain a high level of thermal comfort through the optimization of system operations. Finally, the annual energy consumption was calculated based on the recorded measurements. The results illustrate that this building can reach the ZEB-ready level in Japan. The primary energy consumption can be decreased by approximately 67% compared to the reference by applying the combined system.

Prototypical approach for an individualized standardization process in the context of intelligent construction and automation

Strategies based on an optimal balance between standardization and individualization must be implemented to successfully overcome the current low level of automation in building construction. Project-specific adaptability can be ensured by a combination of automated machine technology and digital planning tools available today. In addition to achieving economic advantages, the focus is on improving sustainability factors, which concern both material consumption and functionality and improved use of resources and energy for building production and operation. The results of research into “lightweight aerogel concrete technology” has shown that an innovative liquid material mixture with insulating properties can be successfully implemented in an automated production process. An adaptive system for standardized wall, ceiling, and floor panels was developed, which can adapt to specific functionality needs and thus address the requirements of individual building tasks while keeping economic as well as architectural factors in mind. The advanced mono-material complies with current European regulations for insulated wall structures, considering the requirements for load-bearing capacity. Due to its homogeneous insulation effect across the entire element section, the aero lightweight concrete allows for intelligent detailing and connection principles and prevents the formation of thermal bridges. The relationship between material composition, material production, construction method, and building operation is essential for a circular planning process. Robotization as a multiple fabrication technology may facilitate these parameters in one cycle. The new technology allows for the crucial transition from research to an end-to-end construction workflow that maps the entire process chain, from concept planning to design and joining principles up to fabrication and assembly.

Ensuring microclimate parameters in the room using radiant ceiling panel cooling systems

The actual purpose of the study was to develop technical solutions for organizing of a panel-radiant cooling system using ceiling devices in a multifunctional building, as well as the calculated justification of its use in comparison with an alternative cooling system: a classic central air conditioning system and a "chiller - fan coil". The comparison was carried out according to the indicators of the microclimate comfort in the serviced room, taking into account the feasibility study. The evaluation method was used to determine the comfort factor of a person's thermal state, taking into account correction coefficients for the main hazards characteristic of multifunctional public buildings. The use of radiant ceiling panel cooling systems increases the comfort of people in the room due to the fact that there are no convective jets with low temperature and high air velocity. At the same time, the most favorable temperature allocation over the height of the room is maintained.

Feasibility study of simplified pipe modeling for analyzing thermal performances of radiant heating and cooling systems

Energy-efficient radiant heating and cooling require surface temperature and thermal capacity analysis. Simplified pipe modeling is applied to save time and resources for numerical analysis when evaluating the radiant system. Therefore, this study investigated the surface temperature distribution and thermal capacity of a radiant system using simplified pipe modeling. To do this, a steady-state heat transfer simulation was performed using Physibel BISCO. The difference between detailed (circular) and simple (rectangular) pipe models and the effect of material thermal conductivity of various layers were analyzed in three types of radiant heating and cooling systems: Embedded Surface System (ESS), Thermally Activated Building System (TABS), and Cooling Radiant Ceiling Panels (CRCP). The simple and detailed ESS and TABS simulation results showed similar surface temperature and heat capacity in various materials. Also, the CRCP simple and detailed models for materials differed in surface temperature and heat capacity, especially when the pipe thermal conductivity was high. The CRCP simple model overstated surface temperature and thermal capacity, which needs heat resistance to solve this overestimation. Further studies are necessary to investigate the discrepancy with different dimensioning and operation conditions, such as water temperature and flow rate.

CFD를 이용한 복합건물 주위의 풍환경 연구

Recently, the problem of the building wind has emerged due to high-rise buildings in narrow spaces. Building wind is an increase of the wind velocity locally because of the structure and arrangement of the building, which can damage the building, deteriorate the walking environment and even cause casualties. In this study, the wind environment of the Pukyong National University Daeyeon Campus Engineering building was investigated using CFD. Also, the ceiling panel collapse, which is one of the cases of damage from the building wind, was analyzed. The average and maximum wind velocity of summer and winter seasons were given to an inlet condition with a wind profile. In pedestrian height, both summer and winter average wind velocities were 3.3 m/s, but the wind velocity increased to 5.7 m/s in summer and 5.5 m/s in winter. The maximum velocity in summer season was observed at 14.6 m/s, but it is increased to 33 m/s around the building. Similarly, the maximum velocity in winter was 13.9 m/s and it is increased to 27 m/s around the building. The maximum force acting on the pedestrian was calculated into 15.5 N in average velocity and 275.5 N in maximum velocity. The strong southwest wind is extremely dangerous to a pedestrian on a narrow pathway between the buildings. Within the area where the ceiling panels collapse occurred, the inlet side wind velocity is slower than the free flow, and the velocity is rapidly increased due to the influence of the structure at the rear part of the outlet side. Accordingly, it seems that negative pressure is formed in the rear portion of the outlet side, and the ceiling panels are collapsed by downward force.

Experimental Characterization and Acoustic Correction of a Multipurpose Performance Hall: The Italian Theatre “Cavallino Bianco”

This study presents the retrofit acoustic dq1esign of the Italian theatre “Cavallino Bianco”. In its historical configuration, the hall had a curved roof with a pressed-plant fiber ceiling, which was demolished and replaced with a wooden roof without a false ceiling, leading to an increase in volume and a worsening of the reverberation time. This study proposed the realization of a wave ceiling and the application of sound-absorbing and reflecting panels on the walls, which have already been implemented. These modifications have affected the acoustic characterization of the theatre, as shown both through on-site measurements during the main construction phases and through numerical simulations. The reverberation time, clarity index, and speech transmission index (STI) are evaluated considering all the variations in the hall over different construction times, and the optimal solution is identified with regard to different specific uses. The final configuration with the new roof, by reducing the volume of the hall and using sound-absorbing materials, significantly reduces the reverberation time (e.g., at 2000 Hz, this reduction is from 2.33 to 1.47). In addition, the hall at full capacity with chairs and people shows evident improvement in terms of the clarity index, allowing the theatre to be used for a wide range of musical genres such as instrumental, symphonic, and opera performances. As regards the Combos 00 (concrete roof without vertical sound acoustic panels) and 01-a/b/c (wooden roof with draped curtains), the STI values are never lower than 0.42 and never higher than 0.70; therefore, the room never experiences poor or excellent conditions at any point. The Combos 01-a and 01-b, which have a non-performing C80, have a good STI index, confirming the difficulty of achieving a configuration that can be optimal a variety of uses. Combo 01 (wooden roof without vertical sound acoustic panels and no draped curtains), which has a good C80 value, presents a lower STI value, with an average performance. The STI values of Combo 02-a (characterized by wave false ceiling and vertical sound acoustic panels) are never lower than 0.52 and never higher than 0.60; therefore, neither poor nor excellent conditions are experienced in the room, but there is still a slight improvement over the combos 00 and 01.