The indoor environment in retrofitted pilot demonstration offices, equipped with advanced radiant ceiling panels that were used for heating and cooling, is evaluated in the paper. Comprehensive ...analyses based on various sets of real case measurements were carried out in order to assess the efficiency and adequacy of the proposed retrofitting concept. It was established that the entire system for tempering the offices operates well, and that the range of indoor air temperatures ensures the highest level of comfort.
U radu se ocjenjuje unutarnja okolina renoviranih ureda koji su, kao pokusni primjer, opremljeni naprednim stropnim isijavajućim pločama koje se primjenjuju za grijanje i hlađenje. Obavljene su ...opsežne analize na bazi raznih nizova stvarnih mjerenja kako bi se ocijenila djelotvornost i prikladnost predložene koncepcije za adaptiranje prostora. Ustanovljeno je da čitav sustav za temperiranje uredskih prostora funkcionira na prikladan način, te da raspon unutarnjih temperatura zraka omogućava postizanje najviše razine udobnosti.
Space cooling using metal ceiling panels is analysed experimentally and theoretically. Measurements are performed in a 2.0×2.5×3
m
3 test chamber with a 1.80×2.16
m
2 cooling panel located on the ...undersurface of the chamber ceiling. Both experimental and theoretical analyses show that the dynamic response of the panel system in conjunction with the thermal comfort conditions is satisfactory for the climate of Greece. Under certain conditions the condensed water vapour may raise dripping problems, for which solutions are proposed. Energy savings exceeding 12.5% may be obtained from the increase in acceptable indoor temperature, but further savings are possible from the higher temperatures of cooling water, which improve the efficiency of solar-driven absorption chillers.
This study focuses on evaluating the energy flexibility potential of an innovative cooling technology that consists of a standard radiant ceiling panel incorporating macro-encapsulated phase change ...materials (PCM). The incorporated PCM allows shifting the energy demand for building cooling. A simulation case study is implemented to investigate the energy flexibility of an office building conditioned by the proposed system in a hot and humid climate. At first, the thermal storage properties of the macro-encapsulated PCM were determined by using the standard ASTM C1784-20. The obtained properties were then used in a whole-building simulation model validated using measurements in a real size walk-in chamber. Three different performance indicators were used to quantify energy flexibility: available storage capacity, storage efficiency, and power shifting capacity. Results show that with an average panel to ceiling ratio of around 66%, the radiant ceiling panel has an average sensible heat storage capacity of around 430 Wh/m2day and average annual storage efficiency of 86%. Results also show that the proposed system can shift the electric power demand for conditioning by 8 h compared to a conventional all-air system. These results confirm the benefit for implementing Demand-Side Management strategies that can exploit the energy demand flexibility of radiant ceiling panels incorporating PCM.
•Demand-Side Management helps to adjust the energy demand according to the energy production.•Thermally activated building systems show great energy savings potential.•A new radiant cooling panel system with PCM is used to promote energy flexibility.•Energy flexibility potential of this new radiant ceiling panel is assessed with innovative metrics.•TES allows to shift the energy demand for conditioning without compromising thermal comfort.
Ceiling radiant cooling panels (RCPs), encapsulating smooth tubes, are the most commonly used terminals in radiant cooling systems. The main limitations of commercial RCPs include low cooling ...capacity and temperature uniformity. This study proposes a passive enhancement approach by internally finning the copper tubes. Using a validated computational model, the performance of finned RCPs is collaboratively assessed in terms of different performance criteria such as the cooling capacity, temperature uniformity, and hydraulic losses. Triangular, rectangular, and circular fin profiles have been studied for different numbers, aspect ratios, and occupied area fractions of the fins. The results indicate the possibility of boosting the cooling capacity and temperature uniformity by 4.64 and 45.2%, respectively, using 8 triangular fins with an area fraction of 0.3 and an aspect ratio of 2.5. The cooling rate can be enhanced by 27.1% using 12 rectangular fins with an area fraction of 0.3 and an aspect ratio of 2.0. Since various considered performance assessment metrics are in direct conflict, a combined weighted performance index is proposed for design selection. By assuming the cooling capacity, cooling rate, temperature uniformity, and pressure losses to be equally important, a balanced design (12 triangular fins with an area fraction of 0.2 and an aspect ratio of 2.0) can enhance the first two criteria by 1.54 and 17.7%, respectively, while increasing the temperature non-uniformity by 3.7% and the pressure losses by 3.4 folds. However, different weighting factors of the proposed index can be used based on the designer's priorities.
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•Radiant ceiling cooling panels (RCP) with internal longitudinal fins are assessed.•Various criteria are considered to evaluate the performance enhancement.•Cooling capacity and temperature uniformity are improved by 4.64 and 45.2%.•The cooling rate can be enhanced by 27.1% using 12 rectangular fins.•A balanced design has 12 triangular fins with an area fraction of 0.2.
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•A macro-encapsulated PCM ceiling panel (MEP) was experimentally investigated.•The MEP was compared to commercially available active ceiling cooling solutions.•When actively ...discharged, the MEPs managed to shift the load to off-peak hours.•The MEP performed similarly to Thermally Active Building Systems (TABS)•The MEP maintained a similar indoor thermal environment to radiant cooling panels.
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.
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.
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•A new PCM-RCC system was designed and studied through full-scale experiments.•The PCM ceiling surface had an average heat transfer coefficient of 8.48 ± 0.97 W/m2 K.•Over 80% of occupancy time was obtained within standard thermal comfort limits.•∼70% of the system's daily consumption occurred during off-peak hours.•A more dynamic, predictive operating schedule improves the system's overall efficiency.
Cooling radiant ceiling panel (CRCP) system has the potential of energy saving, improved thermal comfort as well as good indoor environment. We found that a CRCP with thin air layer has uniform ...surface temperature distribution, which is beneficial for condensation control in hot and humid areas of China. However, with this structure, cooling capacity of the CRCP is decreased. We used surface temperature distribution as well as cooling capacity to have a comprehensive evaluation of the CRCP. We established computational fluent dynamics (CFD) model to calculate the surface temperature distribution and cooling capacity for the CRCP, which is verified by experimental data. Three improved CRCP types with thin air layer are proposed to improve the cooling capacity. The cooling capacities are increased by 43–46% compared to the original CRCP; while uniform surface temperature distribution is retained. We also found the cooling capacities of improved CRCPs are larger than general CRCP type, when maintaining the same minimum surface temperature for condensation control. Meanwhile, this requires lower chilled water temperature and better insulation for pipes, manifolds and fittings than general CRCP type.
•Introduction to a radiant ceiling panel with uniform surface temperature distribution but decreased cooling capacity.•Cooling capacity and temperature distribution for radiant ceiling panel are analyzed by verified CFD model.•Improved radiant panels with higher cooling capacity and uniform surface temperature distribution are proposed.•The improved panel types are more suitable to be applied in hot humid conditions.
•Economic analysis comparing all-air systems with TABS and PCM ceiling systems.•An open-plan office was used as a case study.•Comparison of global costs and dynamic payback periods between the three ...scenarios.•TABS are the cheapest solution, but PCMs represent a flexible alternative to TABS.
High temperature cooling systems have several benefits, such as their ability to create a comfortable indoor environment in an energy-efficient way. Among these systems, those with high thermal mass such as Phase Change Materials (PCM) in integrated components and Thermally Active Building Systems (TABS) are of particular interest, but it is widely believed that these systems are more expensive than traditional all-air systems.
This study investigated the economic performance of TABS, PCM ceiling panels and an all-air system. An open-plan office was used as a case study. The effects of different cooling loads on the economic performance of each system was studied. The global cost and the payback period of each system was compared, following prEN 15459-1 1.
TABS was the cheapest option, having global costs that were 15%, 5%, 20%, 15% and 2% lower than the all-air system for 24, 18, 12, 6 and 3 occupants, respectively. The costs estimated for PCM ceiling scenarios were higher than for the all-air system, but they represent a valid alternative in situations where TABS are not applicable (e.g., renovation projects), especially for high cooling loads, as PCM ceiling panels were only marginally more expensive than the all-air system under high cooling loads.
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