• Energy Research

Abstract In Mexico efforts are being made to promote the use of solar energy for cooling in the Agro-Food Industries (AFI), 120 industries were contacted in order to assess the solar cooling potential application in the sector. One case study was selected among the visited potential end users according to the size of the facility, the information available and their willingness to collaborate in the present project. Data from the industry was used to select the appropriate solar cooling concept and therefore the collector’s typology, and the absorption cooling system. Moreover, the operation of the system was simulated in order to define the optimal size of the collector field required. The proposed cooling system was composed by a Fresnel concentrating collector field to activate a series of air cooled single-effect ammonia–water absorption chillers. The cooling system simulation was carried out with the Transient Systems Simulation Programme (TRNSYS) which allowed to model the collector system that fulfill the required load. The calculated saved electricity was around 19% of the total consumption, this small fraction is due to the fact that the selected facility is operating continuously with very large refrigeration capacities. The specifications of the simulated solar cooling system are presented.

Energy efficiency aware building owners are facing a massive amount of different retrofitting options. However, a quantitative assessment of the different options requires a high level of technical expertise. In this contribution, a fast and novel simulation platform for the assessment of different residential heating system configurations is presented. This platform enables dynamic simulations of the complete heating system, calculating energy/heat consumption and comfort indicators for different heating systems during a full year in less than 5 s on a recent laptop. Another key feature of the platform is the inclusion of a large variety of different heat sources (oil/gas/biomass/carbon boilers, air/brine-water or sorption heat pumps), sensible thermal heat storages, as well as building models. Shortly, this system will be the core of a platform enabling interested users to calculate the energy consumption of different retrofitting options accurately. To validate the system models, the energy consumption of the three reference buildings (single family houses with an annual heating energy demand of 15, 45 and 100 kWh/m2) as per the IEA SHC Task 44 is calculated and compared with reference simulations from established simulation frameworks. The energy consumption of these buildings matches the reference values up to 5% for a full year simulation requiring calculations times between 3.3 and 3.7 s on a recent laptop.

Abstract Energy efficiency in buildings is a crucial topic to reduce worldwide energy consumption and fight climate changes. A key aspect is the assessment of the heat transfer through the opaque elements of the building envelope. One way to do it is modeling the element as a resistors and capacitors network (RC), using the thermal-electrical analogy. In the hourly dynamic method introduced by the recently published standard EN ISO 52016-1:2017, each opaque element is modelled with an RC-network. Italy has implemented in the National Annex A of the Standard an alternative methodology for the definition of the number of nodes and position, based on the detailed layers’ characteristics. In this work, the two methods are described and compared with the exact analytical solution for three cases under sinusoidal boundary conditions. In all the test cases, the results obtained applying the Italian Annex provide better results, with a reduction of the error on the internal flux amplitude between 14% and 67%. In addition, it has been verified that the Italian model is actually well-tuned. Indeed, the amplitude of the external flux is overestimated on average of only 3%, and the phase differences are limited (maximum ±1 h). Lastly, also the effect of the change of the number of nodes, and to move the nodes from the layers’ mid-point to the interface, have been analysed, but none of these strategies were demonstrated able to increase significantly the model accuracy, which can be obtained only reducing the calculation timestep.

This workshop brought together a selection of H2020 EU-funded projects involving experts from the biomass, geothermal, solar thermal, and heat pump sectors to discuss a common strategy for increasing the use of renewable energy technologies for heating and cooling for buildings and industry.

District heating and cooling (DHC), when combined with waste or renewable energy sources, is an environmentally sound alternative to individual heating and cooling systems in buildings. In this work, the theoretical energy and economic performances of a DHC network complemented by compression heat pump and sewage heat exchanger are assessed through dynamic, year-round energy simulations. The proposed system comprises also a water storage and a PV plant. The study stems from the operational experience on a DHC network in Budapest, in which a new sewage heat recovery system is in place and provided the experimental base for assessing main operational parameters of the sewage heat exchanger, like effectiveness, parasitic energy consumption and impact of cleaning. The energy and economic potential is explored for a commercial district in Italy. It is found that the overall seasonal COP and EER are 3.10 and 3.64, while the seasonal COP and EER of the heat pump alone achieve 3.74 and 4.03, respectively. The economic feasibility is investigated by means of the levelized cost of heating and cooling (LCOHC). With an overall LCOHC between 79.1 and 89.9 €/MWh, the proposed system can be an attractive solution with respect to individual heat pumps.

Cities and nations worldwide are pledging to energy and carbon neutral objectives that imply a huge contribution from buildings. High-performance targets, either zero energy or zero carbon, are typically difficult to be reached by single buildings, but groups of properly-managed buildings might reach these ambitious goals. For this purpose we need tools and experiences to model, monitor, manage and optimize buildings and their neighborhood-level systems. The paper describes the activities pursued for the deployment of an advanced energy management system for a multi-carrier energy grid of an existing neighborhood in the area of Milan. The activities included: (i) development of a detailed monitoring plan, (ii) deployment of the monitoring plan, (iii) development of a virtual model of the neighborhood and simulation of the energy performance. Comparisons against early-stage energy monitoring data proved promising and the generation system showed high efficiency (EER equal to 5.84), to be further exploited.