State Space Model for Thermal Analysis of Integrated Structure of Flat Plate Solar Collector and Building Envelope

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Guoqing Yu ◽  
Jirui Zhou ◽  
Yongqiang Tang
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Flat Plate ◽  
State Space ◽  
Solar Collector ◽  
State Space Model ◽  
Building Envelope ◽  
Space Model ◽  
Fluent Simulation ◽  
Flat Plate Solar Collector

Active types of integration of flat plate solar collectors and building envelopes are studied in this paper. The integrated structure of flat plate solar collector and building envelope includes glass cover, absorber plate, tubes, back insulation, and building envelope (we will call it integrated structure later in this paper). With the solar collector integrated with building, the boundary conditions of heat transfer both for the solar collector and the building envelope are changed significantly, and the thermal performance of solar collection and building heat transfer characteristics influences each other. The state space model for thermal analysis of the integrated structure is proposed in this paper, and method for solving this state space model is provided. Moreover, thermal analysis for a particular integrated structure was conducted both by state space model and fluent simulation, then the results were compared and agree well. The state space model has great advantages in time-spending over fluent simulation and it can be used for long-term (several months or a whole year) simulation of the integrated structure. Comparison were made between the integrated structure, detached solar collector and detached single wall based on results calculated by state space method. It shows that (1) integration has little impact on the thermal efficiency of solar collection and the useful heat gain of the integrated structure are nearly the same as that for the single detached solar collector under the same ambient conditions; (2) integration has significant impact on the heat flux across the wall, and the heat flux of the integrated structure is much less than the detached single wall.

scholarly journals Heat Transfer by Nanofluids Through a Flat Plate Solar Collector

2014 ◽  
Vol 90 ◽  
pp. 364-370 ◽  
Author(s):  
Rehena Nasrin ◽  
Salma Parvin ◽  
M.A. Alim
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Solar Collector ◽  
Flat Plate Solar Collector

scholarly journals Higher Order Accurate Transient Numerical Model to Evaluate the Natural Convection Heat Transfer in Flat Plate Solar Collector

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1508
Author(s):  
Nagesh Babu Balam ◽  
Tabish Alam ◽  
Akhilesh Gupta ◽  
Paolo Blecich
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flat Plate ◽  
Solar Collector ◽  
Convection Heat Transfer ◽  
Air Gap ◽  
Convection Flow ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Flat Plate Solar Collector

The natural convection flow in the air gap between the absorber plate and glass cover of the flat plate solar collectors is predominantly evaluated based on the lumped capacitance method, which does not consider the spatial temperature gradients. With the recent advancements in the field of computational fluid dynamics, it became possible to study the natural convection heat transfer in the air gap of solar collectors with spatially resolved temperature gradients in the laminar regime. However, due to the relatively large temperature gradient in this air gap, the natural convection heat transfer lies in either the transitional regime or in the turbulent regime. This requires a very high grid density and a large convergence time for existing CFD methods. Higher order numerical methods are found to be effective for resolving turbulent flow phenomenon. Here we develop a non-dimensional transient numerical model for resolving the turbulent natural convection heat transfer in the air gap of a flat plate solar collector, which is fourth order accurate in both spatial and temporal domains. The developed model is validated against benchmark results available in the literature. An error of less than 5% is observed for the top heat loss coefficient parameter of the flat plate solar collector. Transient flow characteristics and various stages of natural convection flow development have been discussed. In addition, it was observed that the occurrence of flow mode transitions have a significant effect on the overall natural convection heat transfer.

Identification for Control of Low Pressure Die Casting

2010 ◽  
Author(s):  
XinMei Shi ◽  
Daan M. Maijer ◽  
Guy Dumont
Keyword(s):  
Heat Transfer ◽  
State Space ◽  
Die Casting ◽  
State Space Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Process Data ◽  
Space Model ◽  
Model Based ◽  
Virtual Process

Controlling and eliminating defects, such as macro-porosity, in die casting processes is an on-going challenge for manufacturers. Current strategies for eliminating defects focus on the execution of a pre-set casting cycle, die structure design or the combination of both. To respond to process variability and mitigate its negative effects, advanced process control methodologies may be employed to dynamically adjust the operational parameters of the process. In this work, a finite element heat transfer model, validated by comparison with experimental data, has been developed to predict the evolution of temperatures and the volume of liquid encapsulation in an experimental casting process. A virtual process, made up of the heat transfer model and a wrapper script for communication, has been employed to simulate the continuous operation of the real process. A stochastic state-space model, based on data from measurements and the virtual process, has been developed to provide a reliable representation of this virtual process. The parameters of the deterministic portion result from system identification of the virtual process, whereas the parameters of the stochastic portion arise from the analysis and comparison of measurement data with virtual process data. The resulting state-space model, which can be extended to a multi-input multi-output model, will facilitate the design of a model-based controller for this process.

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