Submitted by Maria.Kapsalaki on Tue, 03/22/2016 - 09:05
Typical heat sources in indoor environments include humans, electrical devices, and computers. The number of such sources in operating room environments is even higher due to the presence of surgical staff members and medical equipment. The exchange of thermal energy between indoor surfaces and air is usually modelled by considering contributions from both radiation and convection. Complete heat transfer simulations in indoor environments are normally difficult since radiation models have a tendency to generate numerical instability and, hence, problems with convergent solutions.
Submitted by Maria.Kapsalaki on Thu, 06/19/2014 - 11:19
This paper describes CFD modelling of Double Skin Façades (DSF) with venetian blinds inside the façade cavity. The 2-D modelling work investigates the coupled convective, conductive and radiative heat transfer through the DSF system. The angles of the venetian blind can be adjusted and a series of angles (0, 30, 45, 60 and 80 degrees) has been modelled. The modelling results are compared with the measurements from a section of façade tested within a solar simulator and with predictions from a component based nodal model. Agreement between the three methods is generally good.
Submitted by Maria.Kapsalaki on Wed, 06/18/2014 - 09:28
Energy and environment has been issues concerned all over the world. In China, the application of small size gas-fired air-cooled air-conditioner as an alternative for electric compression air conditioning systems has shown broad prospects due to occurrence of electricity peak demand, lack of water resources and environment-friendly working pairs. Especially, the new air-cooled air-conditioner has many advantages. In order to evaluate its cycle performance, the mathematical model of the new air-conditioner was presented.
Submitted by Maria.Kapsalaki on Wed, 06/18/2014 - 08:53
This paper describes the development of computational thermal manikins (CTMs) to be used in a coupled simulation envrionment to simulate the human thermoregulary response in buildings. 3D graphic design and engineering tools have been used to create CTMs with different postures and clothing insultation levels. Computational fluid dynamics (CFD) simulations of a nude CTM in a space with displacement ventilation has shown good agreement with experimental data of measured convective and radiative heat transfer coefficients.
Submitted by Maria.Kapsalaki on Tue, 06/17/2014 - 14:55
Given the major role played by windows with regard to energy losses and gains from buildings in respectively cold and hot climates, accurate prediction of the heat transfer through its glazing materials is of great importance in building energy simulation. In most of the building energy simulation programs, solar radiation absorption inside glazing layers is usually treated considering that all the radiation is uniformly absorbed in the glazing.
Submitted by Maria.Kapsalaki on Tue, 06/17/2014 - 13:42
In this article, we would like to estimate the surface temperature and heat flow pattern of the four corner walls of building envelope with thermal bridge. In doing so, this study made use of infra-red camera and the heat transfer simulation. The field measurement using infra-red thermography shows thermal bridge and thermal insulation performance of each part of actual existing building envelope.
Submitted by Maria.Kapsalaki on Tue, 06/17/2014 - 13:24
In the framework of the IEA Task 32 (Solar Heating and Cooling Programme), we developed a numeric model to simulate heat transfer in phase change materials (PCM), and experimental data. The analyzed system is bulk PCM plunged in a water tank storage of a solar combisystem (heating and domestic hot water production). The numerical model, based on the enthalpy approach, takes into account hysteresis and subcooling characteristic and also the conduction and the convection in the PCM. This model has been implemented in an existing TRNSYS type of water tank storage.
This paper presents a three-dimensional zonal model, ZAER, for heat transfer and air flow calculations. It is based on an intermediate approach between single-air-node and CFD models. The indoor air volume is divided into macroscopic homogeneous zones. Heat and mass balance equations are written for each zone, while the mass flow rates across the interfaces are calculated by power pressure laws. The simulation tool ZAER allows the determination of temperature fields and air flow distributions inside unconditioned buildings, taking into account external boundary conditions.
This paper presents a numerical study of the coupled airflow and thermal environment in asemi-enclosed space surrounded by buildings. Our numerical simulation couples the heat transfercalculation and the computational fluid dynamic (CFD) airflow simulation in which a RNG(renormalization-group) k-? model is used. Both the solar radiation and building/ground thermal storagewere considered in the heat transfer part.
The three-dimensional heat transfer performance of the slotted light steel-framed composite wall atminimum temperature is simulated using the finite element software of ANSYS. Based on the simulatedresults of heat transfer and the theory of moisture permeation, moisture transfer of the composite wall iscalculated. The results show that there is no condensation at the inner wall surface at the minimumtemperature in Harbin when the thickness of the wall is 229mm. The condensation may occur in the rockwool near the outer wall.