Parametric analysis of the free-suspended ceiling radiant cooling panel using CFD simulation

In this study, the parametric analysis was conducted on different designs of the free-suspended ceiling radiant cooling panel (CRCP) and panel area to improve its cooling performance. A three-dimensional CFD simulation model was developed to investigate the cooling capacity and heat transfer coefficient of the CRCPs. Four parameters were used to be the design parameters: the panel length L, the panel curvature radius r, the void distance between each panel or panel segment d, and the panel coverage area Ac. The L/r ratio was also considered, representing the curvature of panel. Twenty-three designs were compared under seven different cooling load conditions. The cooling capacity curve of each design was given as the regression curve of the cooling capacity and temperature difference between air and panel surface. The results show that the CRCPs with curved shape and void have better cooling performance compared to the reference results. The cooling capacity and heat transfer coefficient increase with increasing curvature radius and coverage area and decreasing the panel length. Additionally, the nominal cooling capacity is the largest when L/r is 0.5. The distance between adjacent panels or panel segments and the panel to the wall is most significant in enhancing cooling capacity

Numerical optimization of a novel ceiling radiant cooling panel combined with wall attached ventilation system

The warm draft that floats from the window has an unfavorable influence on the indoor thermal comfort condition, which heated the indoor air temperature. Therefore, an integrated cooling system combined novel free-suspended ceiling radiant cooling panel (CRCP) with a wall Attached Ventilation (WAV) system is proposed and investigated by using a three-dimensional conjugated computational fluid dynamic (CFD). Two different WAV systems (ceiling inlet/ceiling outlet; ceiling inlet/floor outlet) are examined under various operating conditions. Moreover, the surface response, sensitivity analysis, and optimization of the system's operating condition are carried out via the ANSYS Design Explorer tool. In conclusion, adding the ventilation system with a ceiling inlet and ceiling outlet is more effective than installing a ceiling inlet and a floor outlet. Moreover, the operating conditions with the inlet air velocity of 0.164 m/s, inlet air temperature of 25 °C, and panel surface temperature of 23 °C are selected as the optimum design. Under this condition, the system can prevent warm draft effectively and achieve better thermal comfort using a lower ventilation flow rate, higher ventilation temperature, and higher panel surface temperatures. Thus, it also shows a significant potential of energy-saving accordingly

CFD simulation on the thermal performance of a novel radiant ceiling cooling panel (RCCP) system with segmented and concave surface combined with forced ventilation

The radiant ceiling cooling panel (RCCP) system has been proved thermally efficient and economically but it cannot prevent hot air stream from window individually. Therefore, this study integrated a forced ventilation system with a new RCCP with a segmented and concave surface. In this study, a three-dimensional CFD model is developed and validated with the experimental results. Whereas, the indoor thermal comfort and cooling performance of the proposed coupling are numerically investigated, analyzed, and compared with the RCCP system with ventilation. The results show that the ventilation system is effective to prevent the hot air stream, and it also enhanced the cooling performance of the RCCP. Furthermore, the parametric study and sensitivity analysis are carried out to optimize the operating condition of these two systems to maximize the cooling capacity of the RCCP system and increases the panel surface temperature to mitigate the possible condensation

Numerical and Parametric Study on Open-Type Ceiling Radiant Cooling Panel with Curved and Segmented Structure

A suspended open-type ceiling radiant cooling panel (CRCP) has been proposed recently. The main challenge is improving its cooling performance to overcome limitations for extensive use. Therefore, this study aims to optimize the design of CRCPs with curved and segmented structure to enhance heat transfer. A three-dimensional CFD model was developed to investigate the cooling capacity and heat transfer coefficient of the CRCPs installed inside a single enclosed room. Panel structure was determined based on four dependent parameters: the panel curvature width (L, m), the panel curvature radius (r, m), the void distance (d, m) between each panel or panel segment, and the panel coverage area (A(c), m(2)). The panel surface area (A(s), m(2)) and the ratio of panel curvature width to radius (L/r) were also examined. A total of 35 designs were compared under 7 different cooling load conditions, and 245 cases were carried out. The results show that the nominal cooling capacity and heat transfer coefficient rise with increasing curvature radius and decreasing curvature width. The void distance plays the most crucial role in influencing cooling performance. It is possible to simultaneously improve cooling performance, achieve uniform temperature distribution, and reduce the number of panels through structure optimization

Supplemental Material, Interview_guide_online – “Their Today Is Our Future”: Direct Carers’ Work Experience and Formal Caring Relationships in a Community-Based Eldercare Program in Shanghai

<p>Supplemental Material, Interview_guide_online for “Their Today Is Our Future”: Direct Carers’ Work Experience and Formal Caring Relationships in a Community-Based Eldercare Program in Shanghai by Lin Chen, Minzhi Ye, and Eva Kahana in Journal of Applied Gerontology</p

Determinants of long-term outcome in patients undergoing simultaneous resection of synchronous colorectal liver metastases.

BACKGROUND: It remains unclear which patients can benefit from simultaneous resection of synchronous colorectal liver metastases (SCRLMs). This study aimed to examine the prognostic value of patient- and tumor-related factors in predicting long-term outcomes of patients undergoing simultaneous resection of SCRLMs and to help patients select a suitable therapeutic regimen and proper surveillance. METHODS: Clinicopathological and outcome data of 154 consecutive SCRLM patients who underwent simultaneous resection between July 2003 and July 2013 were collected from our prospectively established SCRLM data and analyzed with univariate and multivariate methods, and the prognostic index (PI) was formulated based on the regression coefficients (β) of the Cox model. The patients were classified into high- and low-risk groups according to the PI value; the cut-off point was the third quartile. RESULTS: The 5-year overall survival rate was 46%, and the 5-year disease-free survival rate was 35%. Five factors were found to be independent predictors of poor overall survival (OS) by multivariate analysis: positive lymph node status, vascular invasion, BRAF mutation, the distribution of bilobar liver metastases (LMs) and non-R0 resection of LMs. Compared to low PI (≤5.978), high PI (>5.978) was highly predictive of shorter OS. Three factors were found to be independent predictors of poor disease-free survival (DFS) by multivariate analysis: tumor deposits, BRAF mutation and bilobar LM distribution. We also determined the PI for DFS. Compared to low PI (≤2.945), high PI (>2.945) was highly predictive of shorter DFS. CONCLUSIONS: Simultaneous resection of SCRLM may lead to various long-term outcomes. Patients with low PI have longer OS and DFS, while those with high PI have shorter OS and DFS. Thus, patients with high PI may receive more aggressive treatment and intensive surveillance, This model needs further validation

Timing of Hepatectomy for Resectable Synchronous Colorectal Liver Metastases: For Whom Simultaneous Resection Is More Suitable - A Meta-Analysis

<div><p>Background</p><p>The optimal timing of resection for synchronous colorectal liver metastases is still controversial. Retrospective cohort studies always had baseline imbalances in comparing simultaneous resection with staged strategy. Significantly more patients with mild conditions received simultaneous resections. Previous published meta-analyses based on these studies did not correct these biases, resulting in low reliability. Our meta-analysis was conducted to compensate for this deficiency and find candidates for each surgical strategy.</p><p>Methods</p><p>A systemic search for major databases and relevant journals from January 2000 to April 2013 was performed. The primary outcomes were postoperative mortality, morbidity, overall survival and disease-free survival. Other outcomes such as number of patients need blood transfusion and length of hospital stay were also assessed. Baseline analyses were conducted to find and correct potential confounding factors.</p><p>Results</p><p>22 studies with a total of 4494 patients were finally included. After correction of baseline imbalance, simultaneous and staged resections were similar in postoperative mortality (RR = 1.14, P = 0.52), morbidity (RR = 1.02, P = 0.85), overall survival (HR = 0.96, P = 0.50) and disease-free survival (HR = 0.97, P = 0.87). Only in pulmonary complications, simultaneous resection took a significant advantage (RR = 0.23, P = 0.003). The number of liver metastases was the major factor interfering with selecting surgical strategies. With >3 metastases, simultaneous and staged strategies were almost the same in morbidity (49.4% vs. 50.9%). With ≤3 metastases, staged resection caused lower morbidity (13.8% vs. 17.2%), not statistically significant.</p><p>Conclusions</p><p>The number of liver metastases was the major confounding factor for postoperative morbidity, especially in staged resections. Without baseline imbalances, simultaneous took no statistical significant advantage in safety and efficacy. Considering the inherent limitations of this meta-analysis, the results should be interpret and applied prudently.</p></div