16 documents found, page 1 of 2
Analysis of the air infiltration through the doorway of a refrigerated room usi...
Gonçalves, J. C.; Costa, J.J.; Lopes, A.M.G.This paper presents the study of the air movement through the doorway of a refrigerated room, using both numerical and experimental approaches. Firstly, a comparison is made between the experimentally observed infiltration rates and the predictions by seven empirical models. For different test conditions of the specific laboratory configuration under analysis (a refrigerated room at laboratory scale), the infil...
Parametric study on the performance of an air curtain based on CFD simulations ...
Goncalves, J. C.; Costa, J.J.; Lopes, A.M.G.This paper presents a parametric study on the performance of an air curtain installed over an access door of a refrigerated room. The aim of this work is to quantify, in an integrated way, the influence of the following geometrical and dynamic parameters: door height; temperature difference between rooms, nozzle thickness; initial orientation angle; jet discharge velocity. A numerical model was used to simulate...
Thermophysical characterization of commercial paraffin-based PCMs for low tempe...
Matias, T.; Soares, N.; Campos-Gonçalves, I.; Costa, J.J.; Simões, P. N.; Durães, L.Reliable data on the thermophysical properties of commercial Phase Change Materials (PCMs) is fundamental for the design and modelling of low temperature Thermal Energy Storage (TES) applications. However, data provided by manufacturers is often insufficient and uncertain. In this work, an experimental study was conducted to determine the relevant thermophysical properties of some commercial paraffin-based PCMs...
The importance of the thermophysical characterization of microencapsulated PCMs...
Soares, N.; Luzio, A.; Matias, T.; Simões, P. N.; Durães, L.; Costa, J.J.This work presents the development of two-dimensional numerical models based on the “additional heat source” and the “effective heat capacity” methods to simulate the thermal behaviour of a microencapsulated phase change material (PCM) - Micronal® DS 5001 X. A purely diffusive, transient model was used, where conduction is the only heat transfer mechanism during phase change. Different ways are evaluated to spe...
Thermal regulation of photovoltaic modules using thermal energy storage units w...
Soares, N.; Gaspar, A. R.; Nunes, F.; Lourenço, V.; Costa, J.J.High operating temperatures reduce the performance of commercial polycrystalline silicon photovoltaic (PV) devices by reducing the efficiency of solar to electrical energy conversion in the PV cells. This paper presents the major developments in the construction of a real-scale experimental apparatus to evaluate the efficiency improvement of PV systems by placing a movable thermal energy storage (TES) unit fill...
Phase change materials for improving the thermal performance of LSF construction
Santos, P.; Gonçalves, M.G.; Martins, C.; Soares, N.; Costa, J.J.Energy is nowadays a prime concern of our society and the buildings’ sector is an important player regarding energy consumption. Energy efficiency and the use of renewable energy sources are two strategies implemented by European Directives to address the energy performance of buildings. The research project PCMs4Buildings – Systems with PCM-filled rectangular cavities for the storage of solar thermal energy fo...
Desenvolvimento de um protocolo experimental para medir o desempenho térmico de...
Gonçalves, M.; Martins, C.; Soares, N.; Santos, P.; Costa, J.J.Neste trabalho faz-se uma breve apresentação do Projeto “PCMs4Buildings – Sistemas com cavidades retangulares com materiais de mudança de fase (PCMs – “Phase Change Materials”) para o aproveitamento de energia solar térmica em edifícios", dando particular destaque à Tarefa nº 4 em curso no Departamento de Engenharia Civil (DEC) da Universidade de Coimbra (UC). O objetivo principal desta tarefa é o desenvolvimen...
Phase change materials for improving the thermal performance of LSF construction
Santos, P.; Gonçalves, M.G.; Martins, C.; Soares, N.; Costa, J.J.
Apresentação do projeto PCMs4Buildings
Soares, N.; Lopes, A. G.; Gaspar, A. R.; Martins, C.; Durães, L.; Gonçalves, M.; Santos, P.; Simões, P. N.; Matias, T.; Costa, J.J.
Energy efficiency and thermal performance of lightweight steel-framed (LSF) con...
Soares, N.; Santos, P.; Gervásio, H.; Costa, J.J.; Simões da Silva, L.The improvement of the use of renewable energy sources, such as solar thermal energy, and the reduction of energy demand during the several stages of buildings' life cycle is crucial towards a more sustainable built environment. This paper presents an overview of the main features of lightweight steel-framed (LSF) construction with cold-formed elements from the point of view of life cycle energy consumption. Th...