scholarly journals Theoretical Study on a Novel Temperature Breakpoint Cyclic Operation to Enhance Desiccant Packed Bed Performance

2021 ◽  
Vol 39 (4) ◽  
pp. 1134-1142
Author(s):  
Siripan Murathathunyaluk ◽  
Prakob Kitchaiya
Keyword(s):  
Theoretical Study ◽  
Packed Bed ◽  
Coefficient Of Performance ◽  
Cycle Times ◽  
Removal Capacity ◽  
Cyclic Operation ◽  
Calculation Results ◽  
High Regeneration ◽  
Temperature Factors ◽  
Recovery Temperature

In a conventional desiccant packed bed dehumidification, the adsorption and desorption operations switched at a constant cycle. However, this Conventional Steady Cyclic (CSC) operation was not performed well under disturbances. Therefore, a Temperature Breakpoint Cyclic (TBC) operation is proposed. A numerical model of the desiccant packed bed dehumidification system has been constructed and validated. The model was then used to assess the desiccant packed bed dehumidification performances in term of moisture removal capacity (MRC) and dehumidification coefficient of performance (DCOP) under various cycle times and temperature factors. The calculation results showed that under CSC, larger amounts of energy were required in the desorption operation, while the TBC exhibited higher performances in term of both MRC and DCOP. Notably, at a high regeneration temperature, the MRC of the TBC was 10% higher than the CSC’s; moreover, the DCOP of the TBC was twice higher than the CSC’s. In other words, at high recovery temperature, both operations exhibited comparable capacities while the energy cost was halved under TBC operation.

scholarly journals Methods for Determining Mold Development and Condensation on the Surface of Building Barriers

Buildings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 4 ◽  
Author(s):  
Aleksander Starakiewicz ◽  
Przemysław Miąsik ◽  
Joanna Krasoń ◽  
Lech Lichołai
Keyword(s):  
Water Vapor ◽  
Vapor Condensation ◽  
Mold Growth ◽  
Vapor Pressures ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Surface Condensation ◽  
Water Vapor Condensation ◽  
Calculation Results ◽  
Temperature Factors

The article presents four equivalent methods for checking mold growth on the surface of building barriers and checking water vapor condensation on their surface. Each method applies to two parallel phenomena that may occur on a building barrier. The first method is to calculate and compare temperature factors. In the second method, the characteristic humidity in the room is calculated and compared. The third method is to calculate and compare the characteristic temperatures in the room. The fourth method is based on the calculation and comparison of characteristic water vapor pressures. Three boundary conditions are presented for each method and phenomenon: when a given phenomenon can occur, when it begins or ends, and when it does not occur. The presented methods systematize the approach to the problem of mold development and surface condensation. The presented calculation results relate to the selected building barrier functioning in specific indoor and outdoor climate conditions. The calculation results confirm the compliance of the presented methods in identifying the phenomenon of mold growth or condensation on the surface of the barrier. A graphical interpretation of the results for each method with periods of occurrence or absence of a given phenomenon is also presented.

Theoretical Study on Ru2+, Cu+, and Fe2+ Complexes Toward the Application in Dye Sensitized Solar Cell

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Nguyen Ngoc Ha ◽  
Mai Anh Tuan ◽  
Dang Xuan Thu ◽  
Luong T. Thu Thuy
Keyword(s):  
Solar Cell ◽  
Theoretical Study ◽  
Organic Ligand ◽  
Absorption Capacity ◽  
Photon Absorption ◽  
Dye Sensitized Solar Cell ◽  
Dye Sensitized ◽  
Calculation Results ◽  
The One ◽  
Electron Attraction

This paper reports the application of the Ru2+, Cu+, and Fe2+ complexes in form of RuL2(SCN)2, CuL2(SCN)2− for dye-sensitized solar cell (DSSC) development. The calculation results, given by quantum chemistry, demonstrated that the complex containing copper is more suitable than the one containing iron. The modification of Cu(I) complex by using various numbers of ligands enhanced photon absorption capacity as well as the absorption range. The addition of an organic ligand such as an electron attraction group to the benzene ring gave a better result as compared to the inorganic ones. Based on the analysis conducted, CuM2(SCN)2− is considered as potential material for N3 replacement.

Dual substrate limitations in upflow packed-bed biofilm reactors — a theoretical study

1997 ◽  
Vol 20 (1) ◽  
pp. 10-16 ◽  
Author(s):  
Shafkat Ali Beg ◽  
Mirza Manirul Hassan ◽  
Muhammad Arshad Saeed Chaudhry
Keyword(s):  
Theoretical Study ◽  
Packed Bed ◽  
Biofilm Reactors ◽  
Dual Substrate

Theoretical Study of the Operation Performance of a Natural Gas CCHP System under Variable Loads

2011 ◽  
Vol 71-78 ◽  
pp. 1765-1768
Author(s):  
Hong Mei Zhu ◽  
Heng Sun ◽  
Tian Quan Pan
Keyword(s):  
Natural Gas ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Theoretical Study ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Operation Performance ◽  
Exhaust Heat ◽  
Calculation Results ◽  
Cooling Loads

A theoretical study of the performance of a CCHP system using natural gas as fuel which consists of gas turbine-steam turbine combined cycle, absorption refrigeration unit and exhaust heat boiler under variable loads was carried out. Two methods to adjust the electric and cooling loads are employed here. One method is to increase the outlet pressure of the steam turbine in the Rankine cycle. Another way is to change the air coefficient of the gas turbine. The calculation results show that the first method can obtain higher energy efficient and is the preferred method. The second way can be employed in case that further more cooling is required.

DESIGN AND ANALYSIS OF THERMOACOUSTIC REFRIGERATOR

2013 ◽  
Vol 21 (01) ◽  
pp. 1350001 ◽  
Author(s):  
B. G. PRASHANTHA ◽  
M. S. GOVINDE GOWDA ◽  
S. SEETHARAMU ◽  
G. S. V. L. NARASIMHAM
Keyword(s):  
Boundary Layer ◽  
Power Density ◽  
Gas Pressure ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Boundary Layer Approximation ◽  
Resonator Design ◽  
Quarter Wavelength ◽  
Calculation Results ◽  
Thermoacoustic Refrigerator

This paper deals with the design and analysis of a quarter-wavelength, 10 W capacity, thermoacoustic refrigerator using short stack boundary layer approximation assumptions. The effect of operating frequency on the performance of the refrigerator is studied using dimensional normalization technique. The variation of stack diameter with average gas pressure and cooling power is discussed. The resonator optimization is discussed and the calculation results show a 9% improvement in the coefficient of performance and 201% improvement in power density for the optimized quarter-wavelength resonator compared to published optimization studies. The optimized resonator design is tested with DeltaEC software and the results show better performance compared to past established resonator designs.

Finite Element Analysis on Frame Structure of Light Steel Temporary Buildings

2013 ◽  
Vol 351-352 ◽  
pp. 808-811
Author(s):  
Zheng Zhang ◽  
Xue Feng Cai ◽  
Yong Chao Ma ◽  
Ji Zhong Zhou
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Simple Structure ◽  
Theoretical Study ◽  
Frame Structure ◽  
Structure Model ◽  
Construction Site ◽  
Element Analysis ◽  
Calculation Results ◽  
Design Loads

Light steel temporary building is commonly used in the construction site, with advantages on simple structure, repeat used and small deadweight. For light steel temporary structure building there are still not enough researches on the mechanical properties and mechanism of action, and there are still not enough relevant standards and requirements to conduct the design and construction of the buildings. In order to precede to theoretical study on frame structure of light steel temporary buildings a method by Finite Element Analysis was proposed. This method is based on FEA software, Ansys. Using this method a monolayer frame structure and a two-story frame structure and a trilaminar frame structure model were analyzed. The calculation results of horizontal displacements under design loads by FEA were obtained and discussed.

Numerical Simulation of a Desiccant Bed for Solar Air Conditioning Applications

1991 ◽  
Vol 113 (2) ◽  
pp. 80-88 ◽  
Author(s):  
S. Farooq ◽  
D. M. Ruthven
Keyword(s):  
Numerical Simulation ◽  
Cycle Time ◽  
Air Conditioning ◽  
Removal Rate ◽  
Optimal Choice ◽  
Coefficient Of Performance ◽  
Thermal Coefficient ◽  
Moisture Removal ◽  
Cyclic Operation

The cyclic operation of a desiccant bed used for solar air conditioning applications has been simulated numerically. The results suggest that the optimal choice of desiccant is not seriously limited by the shape of the isotherm since the effect of isotherm shape on the moisture removal rate can be adequately compensated by appropriate adjustment of the cycle time. The conditions required to maximize the moisture removal rate for any given degree of nonlinearity also satisfy the requirements for maximizing the thermal coefficient of performance.

Sign in / Sign up

Export Citation Format

Share Document