Energy embedded in food loss management and in the production of uneaten food: seeking a sustainable pathway

Recently, important efforts have been made to define food loss management strategies. Most strategies have mainly been focused on mass and energy recovery through mixed food loss in centralised recovery models. This work aims to highlight the need to address a decentralised food loss management, in order to manage the different fractions and on each of the different stages of the food supply chain. For this purpose, an energy flow analysis is made, through the calculation of the primary energy demand of four stages and 11 food categories of the Spanish food supply chain in 2015. The energy efficiency assessment is conducted under a resource use perspective, using the energy return on investment (EROI) ratio, and a circular economy perspective, developing an Energy return on investment ? Circular economy index (EROIce), based on a food waste-to-energy-to-food approach. Results suggest that the embodied energy loss consist of 17% of the total primary energy demand, and related to the food categories, the vegetarian diet appears to be the most efficient, followed by the pescetarian diet. Comparing food energy loss values with the estimated energy provided for one consumer, it is highlighted the fact that the food energy loss generated by two to three persons amounts to one person's total daily intake. Moreover, cereals is the category responsible for the highest percentage on the total food energy loss (44%); following by meat, fish and seafood and vegetables. When the results of food energy loss and embodied energy loss are related, it is observed that categories such as meat and fish and seafood have a very high primary energy demand to produce less food, besides that the parts of the food supply chain with more energy recovery potential are the beginning and the end. Finally, the EROIce analysis shows that in the categories of meat, fish and seafood and cereals, anaerobic digestion and composting is the best option for energy recovery. From the results, it is discussed the possibility to developed local digesters at the beginning and end of the food supply chain, as well as to developed double digesters installations for hydrogen recovery from cereals loss, and methane recovery from mixed food loss.This work has been made under the financial support of the Project Ceres-Procom: Food production and consumption strategies for climate change mitigation (CTM2016-76176-C2-1-R) (AEI/FEDER, UE) financed by the Ministry of Economy and Competitiveness of the Government of Spain

Experimental evaluation of HCFO-1233zd-e as HFC-245fa replacement in an organic rankine cycle system for low temperature heat sources

[EN] In this work an experimental evaluation of the working fluid HCFO-1233zd-E as HFC-245fa replacement in ORC systems for low temperature heat sources has been conducted. A fully monitored ORC module has been used to test both working fluids at different operating conditions. Due to the different densities of the working fluids, the mass flow rate for HCFO-1233zd-E is approximately 20% lower than for HFC-245fa. This causes thermal and electrical powers to be lower for HCF0-1233zd-E than for HFC245fa. However, net electrical efficiency is similar for both working fluids, ranging from 5% to 9.7% in the tested operating conditions. Regarding the expander performance, various performance indicators are addressed. The expander isentropic performance has a maximum value of 75%, with higher values for HCFO-1233zd-E than for HFC-245fa. The overall efficiency of the expander, similar for both working fluids, ranges from 44% to 57% in the experimental test range. (C) 2016 Elsevier Ltd. All rights reserved.The authors thankfully acknowledge the cooperation of Rank (R) for its support in this project.Molés-Ribera, F.; Navarro Esbri, J.; Peris-Pérez, B.; Mota-Babiloni, A. (2016). Experimental evaluation of HCFO-1233zd-e as HFC-245fa replacement in an organic rankine cycle system for low temperature heat sources. Applied Thermal Engineering. 98:954-961. doi:10.1016/j.applthermaleng.2016.01.011S9549619

Energy source impact on the economic and environmental effects of retrofitting a heritage building with a heat pump system

In terms of energy efficiency and the quality of the indoor and outdoor environment, heritage buildings are facing sustainability challenges. This study assessed the feasibility of using renewable energy sources based on air-to-water heat pumps with regard to preserving the historic values of the buildings and their ability to coexist with current energy efficiency and decarbonization requirements, and to prevent their neglect and degradation. A new approach is the use of Building Information Modelling to accurately determine energy demand and select a heating system based on renewable energy sources in such an unusual case as a heritage building. The analysis covers a selection of feasible scenario of the modernization of the over 300 years old building. A particular focus of the study is to compare the use different heat pumps systems. One is a reversible gas absorption air-to-water heat pump and the other is an electricity-powered compressor air-to-water heat pump. The building is currently supplied with a fixed-temperature boiler up to 550 kW with an open combustion chamber fed with coal. It was proven that the proposed retrofit scenario reduces final energy demand by 72.9%, while improving thermal comfort, cutting annual emissions by 121.1 Mg CO2 and 1.0 Mg PM10