Balancing heat saving and supply in local energy planning: Insights from 1970-1989 buildings in three European countries

This study investigates the cost balance between heat energy savings through building envelope retrofits and supply from low-carbon decentralised and centralised technologies in a generic urban district, composed of residential and non-residential buildings from the 1970–1989 construction period. For generalisability, the district is analysed in three European countries (Bulgaria, Germany, Finland), each with distinct weather conditions and price levels. Using bottom-up energy modelling and adopting a societal perspective that includes external costs, the study finds the cost-effectiveness of retrofits to be context-specific. In Bulgaria, retrofits prove largely cost-effective, whereas in Germany and Finland, high labour and material costs pose challenges. Heat pumps, whether decentralised in buildings or centralised in district heating systems, emerge as key options for heat supply, even in cold climates. The study underscores the importance of integrated energy planning in line with the ‘energy efficiency first’ principle and corresponding incentive structures to promote sustainable urban energy systems

Determination of drying parameters in the drying of some fruits and vegetables by microwave rays

Bu çalışmada, ülkemizde yaygın olarak kullanılmayan bunun yanı sıra gelişmiş ülkelerde özellikle baklagiller ve tahılların daha kısa sürelerde kurutma olanağını yaratabilmek amacıyla yaygın olarak kullanılan "mikrodalga ışınlarla kurutma yöntemi" ile bazı sebze ve meyvelerin kurutulmasına çalışılmıştır. Bu amaçla ele alınan bazı sebze ve meyveler için kuruma sırasında gözleme dayalı olarak materyalde büzüşme ve yanığın oluşmadığı, renk, koku ve aroma özelliğinin kaybolmadığı en uygun mikrodalga kademesinin belirlenmesi amacıyla birçok çalışma yapılmış ve yapılan bu çalışmaların sonucunda kurutulmaya çalışılan her materyal için ayrı-ayn kombine kurutma yöntemleri belirlenmiştir. Ayrıca, materyallerin kurutulmuş nemine ulaştırılması sırasında sıcaklık-zaman grafikleri oluşturulmuş ve kuruma sırasında şebekeden çekilen elektrik enerjisi ölçülmüştür. Denemeler sonucunda mikrodalga ışınlarla kurutulmasına çalışılan sebze ve meyvelerin, diğer kurutma yöntemlerine göre oldukça kısa sürelerde kuruduğu, renk, koku ve tat gibi özelliklerini kaybetmediği, uzun süre bozulmadan kalabildiği ve morfolojik açıdan her hangi bir değişime uğramadığı görülmüştür.In this study, an attempt was made in order to dry the eggplant using the method of "microwave drying" a method widely used in the drying of legumes and cereals in advanced countries with the aim of shortening the drying period, although not widely used in our country. Numerous studies were carried out with the aim of determining the most convenient microwave degree, and separate combined drying methods were determined for each material to be dried in the result of these studies. It was determined that no shrinkage and burning occurred and the characteristics of colour, smell and flavor did not disappear in the dried fruits and vegetables, during drying. Time-temperature curves were developed through determining the necessary parameters during the reaching of materials to the drying moisture and the values of electric power drawn from the network during drying were measured and stated graphically. As a result of the trials, it was determined that the vegetables and fruits which were brought into stuffing form, could be dried in rather a short time using microwave rays, compared with the other drying methods; retaining its colour, flavour and taste characteristics and without being subjected to any change, morphologically.Arçelik A.Ş. Bursa Bölge MüdürlüğüGaz Aletleri A.Ş. Firmas

MICROWAVE AND CONVECTIVE DRYING OF BLACKBERRY AND DETERMINATION OF THE EFFECT OF DRYING ON COLOR AND ASCORBIC ACID CONTENTS

Bu çalışma kapsamında yaş baza göre nemi %83.9±0.36 olan böğürtlen (Rubus plicatus L.) meyveleri 100±0.8 g ağırlığında tartılarak 850, 500 ve 160 W güç seviyelerinde mikrodalga yöntemiyle ve 50? sıcaklıkta konveksiyonel kurutma yöntemi ile yaş baza göre nemi %12.45±0.28 oluncaya dek kurutulmuştur. Kurutma işlemleri 850, 500 ve 160 W mikrodalga kurutma seviyeleri için sırasıyla 12.67, 27.17 ve 90.25 dakika; 50? sıcaklıkta yapılan kurutma işleminde ise 272.5 dakika sürmüştür. Yapılan kurutma işlemleri enerji tüketimi açısından incelenmiştir. Kurutma verileri altı farklı ince tabaka kurutma modeli ile modellenmiştir. Karar katsayısının (R²) en büyük olduğu, standart hata (SEE), ki kare (?²) ve ortalama karesel hatanın (RMSE) en küçük olduğu model en iyi model olarak seçilmiştir. Çalışmada ayrıca mikrodalga ve sıcak hava kurutma tekniği ile kurutulan böğürtlen meyvesinin renk değerleri (L, a, b, C ve ?) ve askorbik asit içeriği saptanmış olup taze ürünün renk ve askorbik asit değerleri ile karşılaştırmalı olarak verilmiştir. Buna göre taze ürüne en yakın renk değerinin 850 W mikrodalga güç seviyesinde, taze ürüne en yakın askorbik asit içeriğinin ise 500 W mikrodalga güç seviyesinde elde edildiği belirlenmiştirvalues are shown in comparison with fresh product’s color and ascorbic acid parameters. Accordingly, the closest color parameters to fresh product were obtained at 850 W microwave output powers, while the closest ascorbic acid to fresh product were obtained at 500 W microwave output power

How do system-wide net-zero scenarios compare to sector model pathways for the EU? A novel approach based on benchmark indicators and index decomposition analyses

The use of scenarios and quantitative modelling to identify pathways for energy system transformations in line with the Paris targets is well established in the field of energy and climate policy. The resulting decarbonization pathways depend on both assumptions and the type of model used (e.g., integrated assessment models, energy system, macro-econometric or bottom-up sector models). The objective of this article is to analyze how energy demand sectors in system-wide net-zero scenarios for the EU compare to the results of sector-specific models. To this end, a novel approach referred to as “sectoral benchmarking” is developed and applied, combining the application of standard indicators such as energy intensity, electrification rate or carbon intensity with an index decomposition analysis. The combined approach allows visualizing how system-wide decarbonization pathways differ from the sector models' pathways by bringing the model output in a harmonized format for an efficient comparison. The analysis compares pathways from four different modelling tools: two European system models, one of which is an energy system model (EU TIMES) and the other a macro-econometric model (NEMESIS); as well as two sector-specific models, for transport (ALADIN) and for the industry and building sectors (FORECAST). We evaluate the system model's net-zero scenarios by comparing them to a corridor given by the sector models' current policy and net-zero emission scenarios. This corridor represents what the sector models deem as plausible from their bottom-up perspective within the boundaries of current policies and ambitions to reach net-zero.Our results show that the system model net-zero pathways differ substantially from the sectoral perspective in all sectors. In the industry and building sectors, both system models' decarbonization ambitions are within the sector corridor, but the employed mitigation levers differ. In the industry sectors, the sectoral model achieves substantial CO2 emission reductions with electrification, while the system models use more bioenergy (EU TIMES) or more energy efficiency (NEMESIS). In the building sector, both system models rely mostly on electrification, while the sector models relies on biomass and some district heat and electrification. In the transport sector, both system models' decarbonization ambition is substantially lower than the sector model's.The observed differences are caused by a variety of factors, which we evaluate in this article. One reason is the system models' lower ambition to decarbonize the end-use sectors due to their ability to compensate with negative emission technologies across sectors. In addition, employed mitigation levers differ due to the models' differing capabilities to consider technologies as well as differences in the allocation of bioenergy to sectors.Our findings can be used to determine how the different types of models can inform each other and to make the diverging decarbonization pathways more transparent to policy-makers and other relevant stakeholders