Search

To report three-decade changes of clinical characteristics, progress of treatments, and risk factors associated with mortality and enucleation in patients with retinoblastoma in China.Retrospective cohort study.This multicenter study included 2552 patients diagnosed with retinoblastoma in 38 medical centers in 31 provinces in China from 1989 to 2017, with follow-up data. Kendall's tau-b value was used to describe correlation coefficients between the three eras (between 1989 and 2008, between 2009 and 2013, and between 2014 and 2017) and clinical or demographic features. Hazard ratios and odds ratios were applied to measure risk factors.A total of 324 (13%) patients died and 1414 (42%) eyes were removed. The 1-year, 3-year, and 5-year overall survival rates were 95%, 86%, and 83%, respectively. Patients were diagnosed at a better stage by International Classification for Retinoblastoma over time (Kendall's tau-b value = -0.084, P.001). Pathological risk factors were also observed less in recent eras. New conservative therapies were adopted and used in more patients. The eye removal rate gradually decreased (Kendall's tau-b value = -0.167, P.001). The overall survival rates were 81%, 83%, and 91% in the three eras. By multivariate Cox regression, bilateral tumors and extraocular extension were identified as risk factors for death. Among intraocular disease, Group E indicated higher risk of mortality. By multivariate logistics regression, unilateral tumors, earlier era of diagnosis, and extraocular extension were risk factors for eye salvage failure. Among intraocular retinoblastoma, Groups D and E had higher risk of eye salvage failure.Patients were diagnosed at an earlier stage in recent eras. Conservative therapies, including intra-arterial chemotherapy, were increasingly being used. The above changes may contribute to the decreasing enucleation rate. Although no significant impact was identified on the mortality by the three eras, a decreasing trend was shown.

Purpose This study attempted to estimate the impact of eye-preserving therapies for the long-term prognosis of patients with advanced retinoblastoma with regard to overall survival and ocular salvage. Design Retrospective cohort study covering all 31 provinces (38 retinoblastoma treating centers) of mainland China. Participants One thousand six hundred seventy-eight patients diagnosed with group D or E retinoblastoma from January 2006 through May 2016. Methods Chart review was performed. The patients were divided into primary enucleation and eye-preserving groups, and they were followed up for survival status. The impact of initial treatment on survival was evaluated by Cox analyses. Main Outcome Measures Overall survival and final eye preservation. Results After a median follow-up of 43.9 months, 196 patients (12%) died, and the 5-year overall survival was 86%. In total, the eyeball preservation rate was 48%. In this cohort, 1172 patients (70%) had unilateral retinoblastoma, whereas 506 patients (30%) had bilateral disease. For patients with unilateral disease, 570 eyes (49%) underwent primary enucleation, and 602 patients (51%) received eye-preserving therapies initially. During the follow-up (median, 45.6 months), 59 patients (10%) from the primary enucleation group and 56 patients (9.3%) from the eye-preserving group died. Multivariate Cox analyses indicated no significant difference in overall survival between the 2 groups (hazard ratio [HR], 1.25; 95% confidence interval [CI], 0.85–1.84; P = 0.250). For patients with bilateral disease, 95 eyes (19%) underwent primary enucleation, and 411 patients (81%) received eye-preserving therapies initially. During the follow-up (median, 40.1 months), 12 patients (13%) from the primary enucleation group and 69 patients (17%) from the eye-preserving group died. For bilateral retinoblastoma with the worse eye classified as group E, patients undergoing primary enucleation exhibited better overall survival (HR, 2.35; 95% CI, 1.10–5.01; P = 0.027); however, this survival advantage was not evident until passing 22.6 months after initial diagnosis. Conclusions Eye-preserving therapies have been used widely for advanced retinoblastoma in China. Patients with bilateral disease whose worse eye was classified as group E and who initially underwent eye-preserving therapies exhibited a worse overall survival. The choice of primary treatment for advanced retinoblastoma should be weighed carefully.

The coaxial borehole heat exchangers (BHEs) are commonly used for efficient heat exchange between the heat carrier (usually water) and geothermal energy. Driven by the demand for the performance evaluation of extremely large length-diameter ratio BHEs under various working conditions in the practical engineering, this article presents a high-efficiency finite-volume computational model using variable-length control volumes to study the thermal behaviors of coaxial BHEs. The solution method is validated using data collected from three wells of 47.2 m, 879.6 m and 2,600.0 m depths. It is also used to guide the structural design and performance optimization of BHEs. The comparisons show that the present method can accurately predict the BHE performance with different structures, geological conditions and operating modes. With more reasonable thermal conductivity values, an approximate 100 kW deviation between the predicted and test heat exchange rates was avoided, and RMSE of the outlet temperature was improved from 4.09 to 0.82 for a 2,600 m BHE. The application of the proposed method in engineering projects indicates that setting the periodic operation interval of geothermal wells, according to the building types and heating demand, is an important factor to optimize the utilization of geothermal energy for space heating.

To assess the efficacy of binocular treatment for individual with amblyopia.In this meta-analysis, a comprehensive search of literatures was performed from PubMed, Embase, Cochrane Library and Web of Science databases up to December 21, 2020. Sensitivity analysis was performed for all outcomes. The Begg's test was used to assess the publication bias. Heterogeneity test was conducted for each effect indicator. Indicators were analyzed by random-effects model when the heterogeneity statistic I2 ≥ 50%, on the contrary, indicators were analyzed by fixed-effect model. Standard mean difference (SMD) or weighted mean difference (WMD) was adopted as effect indicators, and the effect amount was expressed as 95% confidence intervals (CIs).A total of 13 literatures including 1146 participants were finally enrolled, with 595 in the intervention group and 551 in the control group. The results indicated that the improvement of amblyopic eye visual acuity [SMD: 0.882, 95%CI: (0.152, 1.613), P = 0.018] in binocular treatment group was better than that in control group. And binocular treatment could improve stereo acuity in individual with amblyopia [WMD: 0.138, 95%CI: (0.068, 0.208), P0.001].Binocular treatment may be beneficial to visual acuity, stereo acuity and binocular function improvement for individual with amblyopia. In clinical practice, binocular treatment can be used as one of the treatments for individual with amblyopia.

The horizontally-butted borehole heat exchanger (BHE) can be used to extract heat efficiently from medium-deep strata, where the groundwater seepage and undisturbed geothermal gradient are critical influence factors. In the application, it is an important and fundamental work to predict the BHE performance for high efficiency geothermal energy utilization. In order to solve its outlet temperature and heat exchange rate, this study develops a semi-analytical solution based on an adjustable multi-layer model associated with the moving finite line source (MFLS) method. The predicted results of a 2505 m horizontally-butted BHE show that the insulation layer and groundwater seepage are beneficial to a better performance. When the insulation depth increases from 0 to 900 m, the outlet temperature can be elevated from 40.5 °C to 48.7 °C, with the fluid volumetric flow rate given at 15 m3·h-1. With a 240 m thick aquifer layer, the groundwater seepage leads to 0.34 °C and 5.73 kW improvements in the outlet temperature and heat exchange rate, respectively. The proposed method successfully solves the problem of predicting the large depth horizontally-butted BHE drilled through various geological formations and aquifers. It can serve as a reference for the rational design of BHE systems for utilizing effectively the geothermal energy.

Hydrophilic nanocomposite membranes have significant advantages in the separation of water vapor which is the core process in air dehumidification. This paper focuses on exploring the micro-mechanism of enhanced separation using graphene oxide-polyvinyl alcohol (GO-PVA) nanocomposite membranes. The sorption and diffusion behaviors of water vapor and nitrogen in GO-PVA membranes were investigated using molecular dynamics (MD) and Monte Carlo (MC) methods. The study showed that embedding GO into a PVA matrix results in a higher glass transition temperature and fractional free volume. The latter is believed to enhance the diffusivity of gas molecules in polymeric membranes. The interaction between the polymer chains and GO nanoparticles notably promotes the adsorption capacity of water vapor and inhibits nitrogen adsorption in the membrane. A water vapor permeance of 8844.07 Barrer and a separation factor of 3.53 could be achieved with the GO-PVA-0.5 membrane. The analysis confirmed that GO has the same effect on single gas and binary gas mixtures

In this article, two model order reduction (MOR) methods of Krylov subspace and Laguerre orthogonal polynomials were employed to the numerical simulation of heat transfer characteristics of ground ...

Radiant system has been increasingly applied in buildings due to its good thermal comfort and energy-saving potential. In this research, a simplified predicted mean vote (PMV) model and sensible cooling load equation were proposed based on human thermal comfort. Simulations were carried out using Airpak to explore relationships among thermal comfort characteristics, design and operation parameters. Results show that radiant surface temperature, fresh-air supply temperature and the area ratio are correlated approximately linearly with the indoor air temperature, while the relative humidity has little effect on the indoor air temperature. The indoor air velocity in the simulated environment was no more than 0.15 m/s, satisfying the requirements of limit values in the occupied zone. The results indicate that the optimum radiant surface temperature ( tc) is 19°C to 23°C when fresh-air supply temperature ( ts) is 26°C. The relative humidity ( φ) should be maintained at 50% to 70%, and the area ratio of radiant panels to total surfaces ( k1) should be kept within 0.15 to 0.38 when the radiant surface temperature is 20°C and the fresh-air supply temperature is 26°C. The simplified PMV model and the sensible load equation can provide reference for panel design based on characteristics of radiant cooling panels with a dedicated fresh-air system.

This study focused on the water vapor removal efficiency by the surface-modified poly(vinyl alcohol)/poly(vinylidene difluoride) (PVA/PVDF) hollow fiber composite membranes with poly(dopamine) (PDA) in the dehumidification process. Two different ways of PDA modification were experimentally investigated and examined in terms of the separation performance of water vapor. A laboratory-scale testing device was set up to measure the water vapor permeance and the water vapor/H2 selectivity. Compared with the pristine PVA/PVDF membrane, the membrane modified using PVA/PDA mixture formed a dense and thin layer with high nitrogen solubility, which was not conducive to improve the water vapor removal efficiency. In contrast, the three-layer PDA–PVA/PVDF-modified membrane with PDA significantly enhanced the dehumidification performance. The influences of modification conditions (PDA concentration and PDA modification time) on the water vapor permeance and water vapor/H2 selectivity of PDA–PVA/PVDF-modified membrane were further studied. The highest water vapor permeance of 2898 GPU was obtained at certain conditions (0.1 g L−1 PDA solution and modification time of 30 min). It was demonstrated that the surface modification with PDA could play an important role in enhancing the hydrophilicity and water vapor/H2 separation performance for PVA/PVDF composite membranes.

Simple Summary The role of organ-conserving surgery has not been explored in retinoblastoma as it has been in other cancers, such as breast cancer lumpectomy, partial nephrectomy for kidney cancer, and partial orchiectomy for testis cancer. This is largely accounted for by the high mortality of extraocular retinoblastoma compared to intraocular retinoblastoma, and fear of iatrogenic tumor spread with intraocular surgery. We propose the little-known word “tylectomy” (“tulos”, Greek for “lump”) to describe the surgical resection of retinoblastoma. Through review of consecutive patients treated by our team between 2012–2014, we compared survival of patients with eye salvage, including tylectomy, to those who had eye salvage without tylectomy or primary enucleation. We found that patients who had tylectomy had superior survival compared to those who had eye salvage without tylectomy (96% vs. 90%), and comparable survival to those with primary enucleation (96% vs. 95%). Our study supports tylectomy as a safe contribution to retinoblastoma management. Abstract Intraocular surgery is tabooed in retinoblastoma management, due to the concern of lethal extraocular spread. We reviewed the outcomes of consecutive children with intraocular retinoblastoma diagnosed at 29 Chinese centers between 2012–2014. We compared the outcomes of three categories of treatment: eye salvage including tylectomy (Group I), eye salvage without tylectomy (Group II), and primary enucleation (Group III). A total of 960 patients (1243 eyes) were diagnosed: 256 in Group I, 370 in Group II, and 293 in Group III; 41 patients abandoned treatment upfront. The estimated 5-year overall survivals (OS) were, for Group I, 94%, for Group II 89%, and for Group III 95%. The estimated 5-year disease-specific survivals (DSS) were, for Group I, 96%, for Group II 90%, and for Group III 95%. Patients in Group I had a significantly higher 5-year DSS than patients in Group II (p = 0.003) and not significantly different than patients in Group III (p = 0.367). Overall survival was not compromised by the inclusion of tylectomy in eye salvage therapy compared to eye salvage without tylectomy or primary enucleation. Disease-specific survival was better when tylectomy was included in eye salvage treatments. Tylectomy as part of multimodal treatment may contribute to the care of retinoblastoma patients with chemotherapy-resistant tumor, eyes with concomitant ocular complications, or at the risk of treatment abandonment.

This study attempted to estimate the impact of eye-preserving therapies for the long-term prognosis of patients with advanced retinoblastoma with regard to overall survival and ocular salvage.Retrospective cohort study covering all 31 provinces (38 retinoblastoma treating centers) of mainland China.One thousand six hundred seventy-eight patients diagnosed with group D or E retinoblastoma from January 2006 through May 2016.Chart review was performed. The patients were divided into primary enucleation and eye-preserving groups, and they were followed up for survival status. The impact of initial treatment on survival was evaluated by Cox analyses.Overall survival and final eye preservation.After a median follow-up of 43.9 months, 196 patients (12%) died, and the 5-year overall survival was 86%. In total, the eyeball preservation rate was 48%. In this cohort, 1172 patients (70%) had unilateral retinoblastoma, whereas 506 patients (30%) had bilateral disease. For patients with unilateral disease, 570 eyes (49%) underwent primary enucleation, and 602 patients (51%) received eye-preserving therapies initially. During the follow-up (median, 45.6 months), 59 patients (10%) from the primary enucleation group and 56 patients (9.3%) from the eye-preserving group died. Multivariate Cox analyses indicated no significant difference in overall survival between the 2 groups (hazard ratio [HR], 1.25; 95% confidence interval [CI], 0.85-1.84; P = 0.250). For patients with bilateral disease, 95 eyes (19%) underwent primary enucleation, and 411 patients (81%) received eye-preserving therapies initially. During the follow-up (median, 40.1 months), 12 patients (13%) from the primary enucleation group and 69 patients (17%) from the eye-preserving group died. For bilateral retinoblastoma with the worse eye classified as group E, patients undergoing primary enucleation exhibited better overall survival (HR, 2.35; 95% CI, 1.10-5.01; P = 0.027); however, this survival advantage was not evident until passing 22.6 months after initial diagnosis.Eye-preserving therapies have been used widely for advanced retinoblastoma in China. Patients with bilateral disease whose worse eye was classified as group E and who initially underwent eye-preserving therapies exhibited a worse overall survival. The choice of primary treatment for advanced retinoblastoma should be weighed carefully.

The radiant wall composited with capillary tubes has been widely applied in heating or cooling systems due to its large heat transfer area, low-temperature heating and high-temperature cooling. In this study, a ratio model of heat transfer in steady-state condition was established, which explores heat transfer capacity from the capillary layer (active layer) towards the indoor and outdoor sides. The experimental data including the radiant surface temperature, the capillary layer temperature and the heat flux distribution were collected in cooling and heating conditions. The proposed ratio model was validated. The results show that the fluctuation of indoor air temperature is relatively small, suggesting that the radiant system possesses higher stability. Results showed that thermal resistances of the composite radiant wall in summer and winter conditions vary greatly due to different moisture contents. With the continuation of the system operation, the calculated values from the ratio model under the steady-state condition were more consistent with average values obtained from experiments under unsteady-state conditions, indicating that the overall heat transfer performance of the composite radiant wall could be properly evaluated by the proposed model in engineering applications.

Flow and heat transfer in curve channel have been studied extensively due to the presence of the secondary flow induced by the centrifugal force. However, for the curved channel with small curvature, weakened centrifugal force reduces the intensity of secondary flow and heat transfer enhancement is attenuated accordingly. For sake of maintaining high heat transfer efficiency in curve channel with a wide range of curvature, periodical wave structure was introduced into the smooth-curve channel by this study. A three-dimensional model of the curve-wave structure was established and numerical simulation was carried out to explore the flow characteristics and heat transfer performance in the proposed channel. In addition, the effects of the wave amplitude on the channel performance were analyzed. The results showed that the heat transfer of smooth-curve channel can be enhanced remarkably by applying wave structure on the channel wall, and the overall performance factor indicates that the heat transfer argumentation outweighs the pressure loss penalty. It was also found that the heat transfer in the curve-wave channel can be further enhanced by increasing wave amplitude. The most effective heat transfer enhancement can be achieved based on the evaluation of the overall performance factor.

Latent heat thermal energy storage is a practical way to solve the intermittent of solar energy. However, the inherent low thermal conductivity of phase change materials (PCMs) hampers their widely-used applications. In this study, a visual experiment test rig was designed to investigate the effect of open-cell metal foam embedded into paraffin (PCM) on the thermal response of a shell-and-tube unit during charging process. High temperature water, selected as heat transfer fluid (HTF), was injected from top of copper tube. The evolution of solid-liquid interface in inside and outside views was captured and recorded by a high-definition camera. 3D interface model was reconstructed based on these interface images and melting fraction was thus calculated. T type thermocouples were arranged separately on the radial and axial positions inside the PCM. Heat transfer annuli filled with PCM and composite PCM were tested under different HTF injection velocities. Experimental results demonstrated that the involvement of open-cell metal foam can dramatically enhance the efficiency of thermal energy storage. Compared with pure PCM, the full melting time of composite PCM was reduced by 64%, and the temperature distribution was more uniformity. Increasing the injection velocities of HTF made little contribution to promoting charging process of two samples.

Thermal energy storage technology has attracted extensive attentions due to its remarkable energy-saving benefits. However, the low thermal conductivity of phase change materials seriously limits the energy storage efficiency, which put forward more stringent requirements for heat transfer enhancement. In this study, a two-dimensional axisymmetric simulation model with natural convection was established for the shell-and-tube thermal energy storage unit. Open-cell metal foam with a porosity of 0.94 and pore density of 15 pore per inch was employed to be arranged in either heat transfer fluid or phase change materials domains. The effects of the metal foam location and the metal foam porosity on the heat storage performance were studied. The numerical method was verified by experimental measurement, achieving good agreement. Results demonstrated that metal foam can significantly enhance heat transfer due mainly to the reduction of thermal resistance in heat transfer fluid. The case that both domains for heat transfer fluid and phase change materials were embedded in porous media can provide the best heat transfer enhancement. Compared with smooth tube without metal foam, the full melting time for this case was reduced by 88.548%; meanwhile, temperature response rate, heat flux and j-factor was increased by 834.27%, 774.90%, 5186.91% respectively. Besides, embedding metal foam into phase change materials can improve the temperature uniformity of phase change materials.

A liquid desiccant air dehumidification system driven by heat pump was established. The performance of cross-flow dehumidifier/regenerator was experimentally investigated. The empirical correlation...

Using paraffin as phase change material, the melting behaviors of pure phase change material and phase change material embedded in open-cell metal foams (composite phase change material) at different inclination angles are studied. Experimental system enabling continuous rotating is designed and built to explore the influence of inclination angles on phase interface evolution and temperature responses inside pure and composite phase change materials. Constant wall temperature is applied on one surface while others are thermally insulated. Experiments are carried out at angles of 0°, 30°, 60°, and 90° respectively. The effects of inclination on the melting behavior of phase change materials are analyzed by visualizing the solid-liquid interface and analyzing the temperature responses. Results demonstrate that the inclination angle has a great influence on the formation and development of natural convection during melting of pure phase change material, affecting the solid-liquid interface propagation and heat transfer rate. Compared with the case at 90°, the full melting time is reduced by 12.28%, 22.81% and 34.21% at 0°, 30° and 60°, respectively. However, when phase change material is melted in open-cell metal foam, heat conduction dominates, and inclination angle has little influence. Melting fractions at different inclination angles are the same and temperature curves at given points overlaps with each other.

Outdoor thermal comfort has been receiving more and more attentions due to the increased demand of outdoor activities during last decades. People require good thermal comfort when they are exposed ...

A liquid desiccant-indirect evaporative cooling (LD-IEC) system has been proposed. The design is able to dehumidify and cool the product air simultaneously in one unit. A computational model has been developed to determine the performance of the heat and mass transfer process. The validation of the model demonstrated good agreement with the experimental data to within 10%. The detailed air treatment process has been theoretically studied. The thermal performance of the LD-IEC has been evaluated. Simulation results showed that the outlet temperature and humidity ratio were influenced by the liquid desiccant film length, intake air temperature, and intake air humidity ratio. For a specific inlet temperature and humidity ratio condition, a desired outlet condition can be obtained by adjusting the length of the liquid desiccant film.

A hybrid evaporative pre-cooled air-conditioning system is introduced for tropical climate applications. The indirect evaporative heat exchanger is employed to pre-cool the ambient humid air before passing through the vapor compression system. A computational model has been developed for the evaporative pre-cooling process. We validated the model by comparing the simulated outlet air temperature against experimental data. The validated model is then used to investigate the performance of the indirect evaporative heat exchanger in terms of the air temperature and humidity profiles. The pre-cooling process is able to reduce the product air temperature and condense water in the product channel. Consequently, the hybrid evaporative pre-cooled air-conditioning system is able to achieve a potential energy saving due the pre-cooling effect and the improvement of the chiller’s efficiency.

In recent years, the utilization of geothermal energy through ground buried heat exchanger to provide heat source for buildings has become extremely attractive within China and all over the world. The effective thermal conductivity of the ground, which may affect the heat transfer process between the buried pipes and the surrounding rock-soil significantly, is a key parameter that governs the prediction of the system performance. This article reviews recently proposed methods to determine the effective thermal conductivities of different rock-soil types containing various substances. The applicabilities of various basic methods to include the effects of porosity, water content, material construction and etc. are documented. According to the deficiencies of basic models, the improved models take into account the effects of the temperature, saturation degree, detailed structure of rock-soil and other parameters to improve the accuracy of predictions. For certain types of rock-soil, experimental measurements are needed to improve the accuracy or verify the results of the improved model in the appropriate ranges of porosity and saturation degree. However, these measurements tend to be expensive and time consuming.

Novel Tb3+ and Eu3+ ions co-doped Ca3Gd(AlO)3(BO3)4 (CGAB) colour-tunable phosphors were synthesized by a traditional high-temperature solid-state reaction. Their physicochemical properties were characterized by powder X-ray diffraction, scanning electron microscope, emission and excitation spectra, and decay lifetimes. Under 352 nm near-ultraviolet excitation, the characteristic transitions of Tb3+ and Eu3+ ions were observed in the emission spectra of CGAB:Tb3+,Eu3+ phosphors. Moreover, the emitting lights of CGAB:Tb3+,Eu3+ phosphors changed from green to orange then red by increasing concentration ratio of Eu3+/Tb3+, due to the energy transfer from Tb3+ to Eu3+. The energy transfer mechanism from Tb3+ to Eu3+ was calculated to be a resonant type of quadrupole-quadrupole interaction. Furthermore, the temperature-dependent emission spectra revealed that the as-prepared phosphors possessed good thermal stability with activation energy around 0.14 eV, while the internal quantum efficiency of optimal red CGAB:0.5Tb3+,0.1Eu3+ phosphor was determined to be 67.5%. Finally, by coating commercial BaMgAl10O17:Eu2+ blue phosphors, commercial (Ba,Sr)2SiO4:Eu2+ green phosphors, and as-prepared CGAB:0.5Tb3+,0.1Eu3+ red phosphors on a 365 nm near-ultraviolet-emitting light-emitting diode (LED) chip, we fabricated a prototype white LED device, which possessed good colour rendering index (CRI = 85.3) and low correlated colour temperature (CCT = 4329 K).

Melting heat transfer in open-cell metal foams embedded in phase-change materials (PCMS) predicted by the volume-averaged method (VAM) was systematically compared with that calculated using direct ...

In recent years, Northern China suffers severe winter haze, which is attributed to extensive residential coal combustion for warm in winter. Chinese government presented proposals of the electrical energy substitute of the fossil fuels to solve the problem. However, the wide applications of electric heating utilities expose the reliability of the electrical grids on the production and transmission side particularly in extreme cold days. In this paper, we studied heating loads and electric load behaviors of an air source heat pump of a case-study suburban residential building of Beijing, China in wintertime in 2016. Firstly, we choose three characteristic days for heating loads analysis, i.e. the coldest, the warmest, and the medium day. Secondly, heating loads of the case-study building were calculated by a building energy simulation program, which is based on a coupled weather data and the building energy transfer. Hourly heating loads of the case-study building in the three characteristic days were studied based on the weather analyses. Thirdly, the electric load behaviors of the air source heat pump used for room heating were investigated. The COP of the heat pump under different operating conditions was calculated. The peak loads and the electric load fluctuations of the heat pump in wintertime were analyzed. This work provided a valuable database on heating loads and electric loads for warm in suburban area in Beijing, so as to help to achieve the electric grid safety.

To solve the severe air pollution problem, Chinese government presented proposals of the electrical heating substitute of the coal combustion for warm. The heat pump is the most economic electrical heating utility. From the start to steady operation of a heat pump, its electrical power is changed with the transient temperature rising of the heated room. Thus, the study of the transient room temperature rising is crucial to evaluate electrical power change of the heat pump. This paper presented a novel numerical simulation method to simulate transient temperature rising of a HVAC room. In this method, velocity of hot air blown off by a fan coil was not constant as usually was, and it was changed with the transient room temperature. This novel simulation method can simulate the real room heating process. The 3-dimensional transient room temperature model was built in a commercial software Fluent. Velocity of hot air blown off by a fan coil was the boundary condition of the model. Hot air velocity was first calculated by the lumped parameter method (LPM), and then it was applied as initial boundary condition of the transient room temperature model. Using this method, the transient temperature rising of a HVAC room was simulated under different outdoor temperatures. Before the heat pump started, the room temperature was assumed to be 3℃ higher than the outdoor temperature. The room was heated until its temperature reached the required temperature. Then, the heat pump steps into the operation state. The time-history of the room temperature from start to steady operation of the heat pump are obtained and analyzed. The results show the novel method can expedite the computation speed. For each time step, the results converged only after 2~3 iterations.

This study focused on the effect of inserting fins into metal foam on the solidification rate. To this aim, a well-designed experimental system with solid-liquid interface visualization was built. ...