• Energy Research

Data availability: Data will be made available on request. An earlier version of this paper was presented during the 36th International Conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems (ECOS 2023) held in Las Palmas de Gran Canaria, Spain, 25–30 June 2023. This paper studies portfolios of electricity- and hydrogen-driven heat pumps, electricity- and hydrogen-driven boilers and thermal energy storage technologies from an energy system perspective. Thermodynamic and component-costing models of heating and cooling technologies are integrated into a whole-energy system cost optimisation model to determine configurations of heating and cooling systems that minimise the overall system cost. Case studies focus on two archetypal systems (North and South) that differ in terms of heating and cooling demand and availability profiles of solar and wind generation. Modelling results suggest that optimal capacities for heating and cooling technologies vary significantly depending on system properties. Between 83 % and 100 % of low-carbon heat is supplied by electric heat pump technologies, with the rest contributed by electric or hydrogen boilers, supplemented by heat storage. Air-to-air electric heat pumps emerge as a significant contributor to both heating and cooling, although their contribution may be constrained by the compatibility with existing heating systems and the inability to provide hot water. Nevertheless, they are found to be a useful supplementary source of space heating that can displace between 20 and 33 GWth of other heating technologies compared to the case where they do not contribute to space heating. The research presented in this paper has been supported by the UK Engineering and Physical Sciences Research Council (EPSRC) [grant number EP/R045518/1] (IDLES Programme).

The key to bio-gasification is the lignocellulosic materials provided in the herbaceous crops which are considered to be renewable energy resources. This study focuses on pretreatments of five sele...

[EN] The monitoring of industry processes can optimize the use of resources and improve its efficiency. In dairy farms, several parameters from the processes must be monitored. This paper proposes the design of a monitoring system for a farm that produces dairy products and jams. Several similar studies are analysed. Based on this, and on the farm characteristics, a novel design is developed. The principal benefits of the system are also exposed. This work was supported by Universidad de las Americas - Ecuador under project SIS.JCG.19.01. The authors would like to thank Monica Guevara, Andrea Maldonado, and Francisca Martinez from Universidad de las Americas - Ecuador for their valuable help and information.

Abstract About 15 million people live in rural communities in the Russian Federation. Most of them are not energetically supplied from the main national infrastructures (electric and gas). People living in such isolated communities use diesel engines for generating electricity and heat. In many cases, diesel is supplied using rail tracks, boats or even helicopters. Consequently, the generation of electricity has very high costs and very low reliability. For this reason, more and more rural isolated communities are using renewable energy sources to decrease their dependency on diesel sources. This study deals with the concept of net-zero multi-energy systems in rural and stand-alone areas. A methodology, based on economical, ecological, technical and social criteria, has been developed for planning the generation capacity and sizing the energy storage units. In addition, controlling algorithms have been developed to deal with the volatility of renewable energy sources (wind and sun) and integrate heat/electricity energy systems. The proposed methodology has been applied to the design of a net-zero energy system for a Siberian rural energy community.

Abstract This paper presents a technoeconomic analysis of a solar combined heat and power (S-CHP) system based on hybrid photovoltaic-thermal (PVT) collectors for distributed cogeneration in a greenhouse tomato-farm in Bari, Italy. The thermal and electrical demands of the greenhouse of interest are currently fulfilled by a gas-fired CHP system that features an internal combustion engine (ICE) prime mover, and partially by an auxiliary gas boiler and electricity from the grid. A PVT-water S-CHP system is designed and sized based on a transient model, with hourly weather data and measured demand data given as inputs. Annual simulations are performed to predict the transient behaviour of the S-CHP system and to assess the system’s energy outputs. The economic profitability of such solution is also evaluated by considering the investment costs and cost savings due to the reduced on-site energy consumption. The results show that, with an installation area of 30,000 m2, the PVT S-CHP system is able to cover up to 73% of the annual thermal demand of the greenhouse, while delivering a net electrical output 2.6 times that of the annual electrical demand. This performance is similar to that achieved by the equivalent ICE-CHP system (92% and 2 times, respectively). Furthermore, the total annual cost saving of the PVT S-CHP system is more than 6 times higher than that of the ICE system, due to the much lower fuel cost of the PVT system. Similarly, the potential CO2 emission reduction associated with the PVT system is considerably higher, at 3010 tCO2/year saved (vs. 86 tCO2/year). The payback time of the PVT system is not significantly longer than that of the ICE system (10.4 years vs. 8.4 years), but its levelized cost of energy is much lower (0.076 €/kWh vs. 0.132 €/kWh) due to the higher annual cost savings. These results indicate that such PVT S-CHP systems have an excellent technoeconomic potential in the proposed greenhouse applications and could be competitive over conventional fossil-fuel-based ICE-CHP systems in terms of energetic, economic and also environmental metrics.

Abstract This paper presents a multi-scale framework for the design and comparison of centralised and distributed heat generation solutions. An extensive analysis of commercially available products on the UK market is conducted to gather information on the performance and cost of a range of gas-fired combined heat and power (CHP) systems, air-source heat pumps (ASHPs) and ground-source heat pumps (GSHPs). Data-driven models with associated uncertainty bounds are derived from the collected data, which capture cost and performance variations with scale (i.e., size and rating) and operating conditions. In addition, a comprehensive thermoeconomic (thermodynamic and component-costing) heat pump model, validated against manufacturer data, is developed to capture design-related performance and cost variations, thus reducing technology-related model uncertainties. The novelty of this paper lies in the use of multi-fidelity approaches for the comparison of the economic and environmental potential of important heat-generation solutions: (i) centralised gas-fired CHP systems associated with district heating network; (ii) gas-fired CHP systems or GSHPs providing heat to differentiated energy communities; and (iii) small-scale micro-CHP systems, ASHPs or GSHPs, installed at the household level. The pathways are evaluated for the case of the Isle of Dogs district in London, UK. A centralised CHP system appears as the most profitable option, achieving annual savings of £13 M compared to the use of decentralised boilers and a levelised cost of heat equal to 31 £/MWhth. However, if the carbon intensity of the electrical grid continues to reduce at current rates, CHP systems will only provide minimal carbon savings compared to boilers (

Argentina targets a 20% share of renewables in the energy mix by 2025 and a 15% emissions reduction by 2030, while at the same time removing subsidies for grid electricity. This paper aims to provide a feasible solution for small farm owners for sustainable and affordable energy: a grid-connected hybrid system able to fulfill the demand in a cheaper, reliable and sustainable way. The case study of an existing dairy farm in Carmen de Areco, Buenos Aires, is taken. A grid-connected hybrid system with solar photovoltaics, unheated anaerobic digestion (AD) coupled to an internal combustion engine and storage system, was selected. The size of the hybrid system was optimized via a mathematical model that compared different technologies. The interrelation between sources was economically optimized in order to match the demand on an hourly basis. The scenario comparison defined the optimal solution for this case study, which was the installation of an unheated AD plant with 2.4 kW capacity, and 16 solar panels with a capacity of 5.2 kW, added to a shift in the demand profile. The initial investment required is 17,042 USD, with a payback of 3.4 years and a GHG reduction of 275.9 tons of CO2 eq per year.

In this research, a technoeconomic comparison of energy efficiency options for energy districts located in different climatic areas (Naples, Italy and Fayoum, Egypt) is presented. A dynamic simulation model based on TRNSYS is developed to evaluate the different energy efficiency options, which includes different buildings of conceived districts. The TRNSYS model is integrated with the plug-in Google SketchUp TRNSYS3d to estimate the thermal load of the buildings and the temporal variation. The model considers the unsteady state energy balance and includes all the features of the building’s envelope. For the considered climatic zones and for the different energy efficiency measures, primary energy savings, pay back periods and reduced CO2 emissions are evaluated. The proposed energy efficiency options include a district heating system for hot water supply, air-to-air conventional heat pumps for both cooling and space heating of the buildings and the integration of photovoltaic and solar thermal systems. The energy actions are compared to baseline scenarios, where the hot water and space heating demand is satisfied by conventional natural gas boilers, the cooling demand is met by conventional air-to-air vapor compression heat pumps and the electric energy demand is satisfied by the power grid. The simulation results provide valuable guidance for selecting the optimal designs and system configurations, as well as suggest guidelines to policymakers to define decarbonization targets in different scenarios. The scenario of Fayoum offers a savings of 67% in primary energy, but the associated payback period extends to 23 years due to the lower cost of energy in comparison to Naples.