| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 4.81 MB | Adobe PDF |
Authors
Abstract(s)
À medida que a perceção dos impactos ambientais das indústrias vai aumentando, torna-se cada vez mais necessária uma mudança para materiais convencionalmente designados por “materiais verdes”, contribuindo assim para uma economia mais sustentável. Este trabalho teve como objetivo o estudo da possibilidade da utilização de aglomerados de cortiça no transporte alimentar, comparando com soluções de poliestireno expandido (EPS) atualmente existentes no mercado. Para isso, inicialmente, mediu-se a condutividade térmica das amostras de aglomerados de cortiça e de poliestireno expandido através do método “Hot Disk”, obtendo-se os valores de 0,07596 ± 1,52×10-4 (W/m.k) para o aglomerado de cortiça, relativamente superior do que os valores encontrado na literatura (entre 0,050 e 0,0595 W/m.k) e de 0,03182 ± 1.6×10-5 (W/m.k) para o poliestireno expandido, ligeiramente inferior do que o valor encontrado na literatura (0,040 W/m.k). De seguida, montaram-se duas caixas, uma com placas de aglomerados de cortiça e outra com placas de poliestireno expandido, e realizaram-se testes de estabilidade térmica na câmara de ensaios térmicos do laboratório da Advanced Products Portugal (LAECT) para comparar a performance do isolamento térmico dos dois materiais. Assim, verificou-se que, para testes sem produto (cenários A e B), a caixa de aglomerado de cortiça atingiu a temperatura exterior de teste (25 ºC) mais lentamente do que o interior da caixa de poliestireno expandido. Contudo, para testes com produto (cenário C), a temperatura no interior da caixa do aglomerado de cortiça apenas foi inferior do que a da caixa de poliestireno expandido durante os primeiros 45/70/290 minutos de cada teste, para a 1ª, 2ª e 3ª repetição, respetivamente. De seguida, calculou-se a energia necessária para subir a temperatura de cada caixa e do seu interior, para cada teste, até 25 ºC, com o objetivo de descobrir qual dos sistemas necessita de mais energia para elevar a sua temperatura até à temperatura exterior de teste. Deste modo, tornou-se possível concluir que não é apenas a condutividade térmica que influencia a performance de isolamento térmico das caixas. De facto, calor específico e a temperatura de estabilização devem ser tidas em consideração no transporte de alimentos, para que se tire o máximo de rendimento da utilização de aglomerados de cortiça para o transporte alimentar.
As the perception of the environmental impacts of industries increases, a change to materials conventionally called “green materials” becomes increasingly necessary, thus contributing to a more sustainable economy. This work aimed to study the possibility of using cork agglomerates in food transport, comparing with expanded polystyrene (EPS) solutions currently on the market. For this, initially, the thermal conductivity of the samples of cork agglomerates and expanded polystyrene were measured using the “Hot Disk” method, obtaining the values of 0,07596 ± 1,52×10-4 (W/m.k) for cork agglomerate, higher than the ones found in literature (between 0,050 e 0,0595 W/m.k) and 0,03182 ± 1.6×10-5 (W/m.k) for expanded polystyrene, a little lower than the one found in literature (0,040 W/m.k). Then, two boxes were assembled (one with cork agglomerate plates and the other with expanded polystyrene plates) and thermal stability tests were carried out in the thermal test chamber laboratory of the Advanced Products Portugal (LAECT) to compare the thermal insulation performance of the two materials. Thus, it was found that, for tests without product (scenarios A and B), the interior of the cork agglomerate box reached the external test temperature (25 ºC) slower than the interior of the polystyrene box. However, for tests with product (scenario C), the temperature in the interior of the cork agglomerate box was only lower than the temperature in the expanded polystyrene box for the first 45/70/290 minutes of each test, for the 1st, 2nd and 3rd, respectively. Then, the energy needed to raise the temperature of each box and its interior up to 25 ºC, for each test, was calculated, to find out which of the systems needs more energy to raise its temperature to the external test temperature. This way, it became possible to conclude that it is not only the thermal conductivity that influences the thermal insulation performance of the boxes. In fact, the specific heat and the stabilization temperature must be taken into account when transporting food, so that the maximum efficiency is obtained from the use of cork agglomerates for food transport.
As the perception of the environmental impacts of industries increases, a change to materials conventionally called “green materials” becomes increasingly necessary, thus contributing to a more sustainable economy. This work aimed to study the possibility of using cork agglomerates in food transport, comparing with expanded polystyrene (EPS) solutions currently on the market. For this, initially, the thermal conductivity of the samples of cork agglomerates and expanded polystyrene were measured using the “Hot Disk” method, obtaining the values of 0,07596 ± 1,52×10-4 (W/m.k) for cork agglomerate, higher than the ones found in literature (between 0,050 e 0,0595 W/m.k) and 0,03182 ± 1.6×10-5 (W/m.k) for expanded polystyrene, a little lower than the one found in literature (0,040 W/m.k). Then, two boxes were assembled (one with cork agglomerate plates and the other with expanded polystyrene plates) and thermal stability tests were carried out in the thermal test chamber laboratory of the Advanced Products Portugal (LAECT) to compare the thermal insulation performance of the two materials. Thus, it was found that, for tests without product (scenarios A and B), the interior of the cork agglomerate box reached the external test temperature (25 ºC) slower than the interior of the polystyrene box. However, for tests with product (scenario C), the temperature in the interior of the cork agglomerate box was only lower than the temperature in the expanded polystyrene box for the first 45/70/290 minutes of each test, for the 1st, 2nd and 3rd, respectively. Then, the energy needed to raise the temperature of each box and its interior up to 25 ºC, for each test, was calculated, to find out which of the systems needs more energy to raise its temperature to the external test temperature. This way, it became possible to conclude that it is not only the thermal conductivity that influences the thermal insulation performance of the boxes. In fact, the specific heat and the stabilization temperature must be taken into account when transporting food, so that the maximum efficiency is obtained from the use of cork agglomerates for food transport.
Description
Keywords
Cortiça Transporte alimentar Isolamento térmico Poliestireno expandido Cork Food transport Thermal insulation Expanded polystyrene