Suchergebnisse

Discusses the physical and mathematical analysis of transport phenomena associated with food processing. This title presents various models that describe many of the important physical and biological transformations that occur in food during processing.

This paper presents a comprehensive review of all correlations and experimental studies available in the literature to determine the heat transfer coefficient of supercritical CO2 flowing in heat exchangers. The different applications in which it is used are also reviewed and discussed. The correlations obtained from extensive experimental measurements are presented for different geometries (horizontal, vertical and inclined tubes, closed-loop circular pipes, and mini-channels) and dimensions. The review shows that there is a lack of a unique universal correlation for each geometry, suggesting the need for more work in this area. ; The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement N°PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES), and the funds received by the Royal Society of New Zealand. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

The use of active thermal energy storage can provide energy savings, cost reduction and CO2 mitigation by reducing energy demand for heating and cooling, allowing the use of peak load shifting strategies and enhancing the introduction of renewable energies in the sector. The high investment cost of these systems makes mandatory an appropriate control in order to maximize the energy benefits during its operation. Within this context artificial intelligence techniques have been successfully used to control active thermal energy storage units. This paper uses an experimentally validated numerical tool to study the effect of different control strategies on the performance of one TES system applied to the building sector, a ventilated facade with PCM which uses free cooling. Three different strategies were designed to control the ventilated facade based on cost savings, energy reduction and CO2 mitigation, under different climatic conditions. Results show robust benefits in the three tested control strategies, achieving average savings in comparison to a manual operation of the system of 4.3%, 7.8%, and 16.7%. Moreover, the paper shows that when the control strategy is focused on optimizing cost, the other two benefits claimed by TES systems (energy and CO2 mitigation) are significantly reduced. ; The work is partially funded by the Spanish Government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), TIN2015-71799-C2-2-P and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and the city hall of Puigverd de Lleida. This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement N°PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 657466 (INPATH-TES), and the fund received by the Royal Society of New Zealand. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

Thermal energy storage (TES) is a technology with a high potential for different thermal applications. It is well known that TES could be the most appropriate way and method to correct the gap between the demand and supply of energy and therefore it has become a very attractive technology. In this paper, a review of TES for cold storage applications using solid–liquid phase change materials has been carried out. The scope of the work was focussed on different aspects: phase change materials (PCMs), encapsulation, heat transfer enhancement, and the effect of storage on food quality. Materials used by researchers as potential PCM at low temperatures (less than 20 C) are summarized and some of their thermophysical properties are reported. Over 88 materials that can be used as PCM, and about 40 commercially available PCM have been listed. Problems in long term stability of the materials, such as corrosion, phase segregation, stability under extended cycling or subcooling are discussed. Heat transfer is considered both from theoretical and experimental point of view and the different methods of PCM encapsulation are reviewed. Many applications of PCM at low temperature can be found, such as, ice storage, conservation and transport of temperature sensitive materials and in air conditioning, cold stores, and refrigerated trucks. ; The work partially funded by the Spanish Government (ENE2008-06687-C02-01/CON and ENE2011-22722) and the European Union (COST Action COST TU0802 and project EFFIBUILDINGS – FP7-PEOPLE-2009-IIF-/-253914). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2009 SGR 534). Eduard Oró would like to thank the University of Lleida for his research fellowship.

Public universities face the challenge of retrofitting the actual campus buildings into nearly zero-energy buildings (NZEB). In this study, a novel methodology for evaluating historical energy use and renewable energy production for all the buildings of a university, including hourly, daily and monthly data assessments is presented. This analysis is useful as a baseline for comparisons with future energy retrofits and enables determining the current gap between actual energy indicators at building and campus levels and the established limits for NZEB non-residential buildings in the European Union. The methodology is applied to a case study at the University of Lleida, a typical average-size university in Spain. Results show a wide variation in energy use among campus buildings, ranging between 50 and 470 kWh/m2 year. Constant or slightly increasing energy use and decreasing trends in renewable energy generation are observed. The daily electricity profiles have shown similar patterns among buildings and substantial potential energy savings during unoccupied periods. In the NZEB analysis, the average non-renewable primary energy use is about 4 times higher than the maximum estimated Spanish threshold range of 45-55 kWh/m2 year. Deep energy renovation strategies are, thus, needed for universities to meet EU NZEB targets. ; The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE).

In recent years, the concept of energy-efficient buildings has attracted widespread attention due to growing energy consumption in different types of buildings. The application of thermal energy storage (TES) systems, especially latent heat energy storage (LHES), has become a promising approach to improve thermal efficiency of buildings and hence reduce CO2 emissions. One way to achieve this, could be by implementing a model predictive control (MPC) strategy, using weather and electricity cost predictions. To this end, a heat exchanger unit containing a phase change material (PCM) as a LHES medium, thermally charged by solar energy was incorporated into three versions of a standard building. This paper reports on the use of EnergyPlus software to simulate the heating demand profile of these buildings, with Solving Constraint Integer Programs (SCIP) as the optimization tool. After applying MPC strategy, the energy costs of different building types were evaluated. Furthermore, the effect of prediction horizon and decision time step of MPC strategy, and PCM mass capacity on the performance of the MPC were all investigated in 1 and 7-day simulations. Results showed that by increasing the prediction horizon and PCM mass, more cost saving could be obtained. However, in terms of decision time step, although the study revealed that increasing it led to a higher energy saving, it made the system more sensitive to sharp changes as it failed to provide an accurate reading of the parameters and variables. ; The study was partially funded by the Spanish Government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is the certified agent for TECNIO in the category technology developers for the Government of Catalonia. The research leading to these results also received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE).

Relocatable, transportable or off-site constructed lightweight buildings typically undergo sharp indoor temperature fluctuations in the heating and cooling seasons due to the lack of sufficient thermal mass in their envelopes, resulting in high energy consumption to provide the zone with comfort temperature. The application of phase change materials has been suggested as a promising solution to control the indoor thermal condition in buildings. This work is an attempt to support the application of PCM technology in lightweight relocatable buildings as a passive alternative to save energy under different weather conditions. The numerical results highlighted the potential of using PCM-enhanced gypsum boards in lightweight buildings to increase the energy performance during both heating and cooling seasons in arid and warm temperate main climate areas. ; The authors from Chile acknowledge to CONICYT/FONDAP No. 15110019. This work has been partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economía y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Paula Marin thanks fellowship CONICYT-PCHA/doctorado nacional/2015-21151359.

According to the IPCC, societies can respond to climate changes by adapting to its impacts and by mitigation, that is, by reducing GHG emissions. No single technology can provide all of the mitigation potential in any sector, but many technologies have been acknowledged in being able to contribute to such potential. Among the technologies that can contribute in such potential, Thermal Energy Storage (TES) is not included explicitly, but implicitly as part of technologies such as energy supply, buildings, and industry. To enable a more detailed assessment of the CO2 mitigation potential of TES across many sectors, the group Annex 25 "Surplus heat management using advanced TES for CO2 mitigation" of the Energy Conservation through Energy Storage Implementing Agreement (ECES IA) of the International Energy Agency (AEI) present in this article the CO2 mitigation potential of different case studies with integrated TES. This potential is shown using operational and embodied CO2 parameters. Results are difficult to compare since TES is always designed in relation to its application, and each technology impacts the energy system as a whole to different extents. The applications analyzed for operational CO2 are refrigeration, solar power plants, mobile heat storage in industrial waste heat recovery, passive systems in buildings, ATES for a supermarket, greenhouse applications, and dishwasher with zeolite in Germany. The paper shows that the reason for mitigation is different in each application, from energy savings to larger solar share or lowering energy consumption from appliances. The mitigation potential dues to integrated TES is quantified in kg/MW h energy produced or heat delivered. Embodied CO2 in two TES case studies is presented, buildings and solar power plants. ; The work was partially funded by the Spanish government (project ENE2011-22722 and ENE2011-28269-C03-02). The authors would also like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123) and DIOPMA (2014 SGR 1543). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° PIRSES-GA-2013-610692 (INNOSTORAGE). The work of ZAE Bayern in the development of the mobile sorption heat storage was supported by the German Federal Ministry of Economics and Technology under the project code 0327383B. ZAE Bayern thanks the Bosch-Siemens-Hausgeräte GmbH for the fruitful collaboration in the development of a sorption storage for dishwashers.