• Energy Research

Abstract This paper presents the experimental tests on desiccant regeneration carried out in a packed column with the hygroscopic solution H 2 O/LiBr. Two different packed columns have been tested: a random column consisting of 1” Pall Ring elements and a structured column Mellapack 250Y. The experimental results are reported in terms of desiccant concentration increase, regeneration effectiveness and air side pressure drop. The experimental tests show that desiccant regeneration requires a temperature level around 50 °C that can be easily obtained by using solar energy or heat recovered from an industrial process or from a thermal engine. The random column shows regeneration performance 20–25% higher than structured column, whereas the structured column shows air side pressure drop from 65% to 75% lower. The experimental results have been compared against a one-dimensional simulation code of a packed column: a fair agreement is found between experiments and simulation.

This paper presents the experimental tests on the chemical dehumidification of air by a liquid desiccant and desiccant regeneration carried out in an absorption/desorption tower with random packing. The experimental set-up is fully described together with measurements, procedures, data reduction, and accuracy. The experimental tests include 46 dehumidification runs and 38 desiccant regeneration runs carried out with the traditional hygroscopic solution H2O/LiBr and the new solution H2O/KCOOH in the typical operative ranges of air conditioning applications. The experimental results are reported in terms of humidity reduction, desiccant concentration change, and tower efficiency. The experimental tests show that chemical dehumidification of air by liquid desiccants ensures consistent reduction in humidity ratio, which is suitable for the application to air conditioning or drying processes. The experimental results are also compared to a one-dimensional simulation code of a packed tower: a fair agreement was found between experimental and calculated performance.

Abstract The energy performance of a window depends on its thermal transmittance, the glazing solar transmittance, and the air leakage due to the frame and installation airtightness. In new installations air leakage represents a quite small term which is almost independent from the window and in particular from the glazing system selection. The contributions of the two other terms to the building thermal balance are not independent to each other: the most effective thermal insulating glazing, as triple glazings, are generally characterized by low solar transmittance reducing solar gains. The thermal energy balance of the building is then affected not only in summer but also in winter, potentially increasing heating energy need. This work evaluates the impact of different kinds of glazing systems (two double and two triple glazings), window size (from 16% to 41% of window to floor area ratio), orientation of the main windowed facade and internal gains on winter and summer energy need and peak loads of a well insulated residential building. The climatic data of four localities of central and southern Europe have been considered: Paris, Milan, Nice and Rome. A statistical analysis has been performed on the results in order to identify the most influencing parameters.

Abstract The pattern and permeability characteristics that compose three-dimensional (3D) textiles are important as a textile shading component to the architecture, engineering and construction (AEC) industry. Moreover, due to their complex geometry, 3D fabrics require a detailed modeling for correct evaluation of performance. This paper aims to present and investigate the optical properties of six 3D fabrics proposed as an alternative to traditional roller blind shading systems, which could guarantee high daylight availability and visual comfort. The light transmission distribution for the different samples has been characterized by carrying out angular visual transmittance measurements, using integrating sphere optical benches, and virtual modeling using Radiance's genBSDF tool. The Bidirectional Scattering Distribution Function (BSDF) calculated with Radiance shows a good fit with the optical angular measurements, which were used as a benchmark and to calibrate models. The performance of the 3D textiles, in terms of illuminance, daylight availability, and glare, was assessed considering two of the set of 3D textiles as alternative materials for a movable internal roller shade system in an open office. The innovative system was compared with a traditional single layer fabric roller blind under different shading control strategies, 3D fabrics demonstrate the potential of increasing Daylight Autonomy while providing better uniformity and better connection with the outdoors due to a higher openness factor. The shading effect created by the 3D geometry of the textile can increase the openness factor while restricting glare.

Abstract In principle, absorption chillers of the ammonia-water type could work at temperatures well below the usual air-conditioning temperatures, arriving at the range 250–260 K, which can be useful for refrigeration applications. This possibility is studied for an air-cooled machine, comparing the results with the experimental data supplied by a manufacturer that recently commercialized such a refrigerator. The prediction is fair, and the study allows an insight into the internal parameters and into the possible behaviour for more severe conditions than those studied.

The present study applies an approach to analyze the stress induced on people on the autism condition. Dedicated questionnaires were prepared, in order to guarantee an inclusive participation and then applied by means of two different surveys in living and extended care unit environments. Results permit to highlight that: (i) the four comfort domains show similar sensitivity trends, with acoustics having the greatest impact on people with autism spectrum disorder (ASD), while thermo-hygrometric, visual and IAQ sensitivity decreases as the stress scale increases; (ii) Severity of autism influenced the acoustic sensitivity, while age and the considered environment influenced thermo-hygrometric, visual and IAQ sensitivities. The proposed approach can be applied to well-being studies involving people with other types of conditions which could alter their perception of the built environment.

Abstract This paper proposes an analysis methodology that can be applied by governments and local administrations to evaluate energy retrofit programs that involve entire building categories. Through a simulation based approach, that combines detailed energy modelling and algorithmic optimization, the analysis methodology is aimed to assess the magnitude of achievable energy savings for various retrofit levels along a cost-optimal path towards achieving net zero energy operation conditions. The proposed approach allows to identify the most cost-effective energy efficiency measures (EEMs) for building retrofits and their required investment costs. The retrofit potential benefits of the Italian office buildings stock is used as a case study to illustrate the application of the proposed analysis methodology. The results of the evaluation analysis for the Italian office building stock indicated a potential primary energy savings of 54% (i.e., 8000 GWh), when retrofitted through optimal combinations of EEMs and rooftop integrated photovoltaics. The optimal set of EEMs showed strong dependency on building typology and climate. In general, the cost-optimal combinations of EEMs and rooftop PV systems did not allow to reach net-zero energy operation conditions for any Italian office building type and climatic zone.

The analysis of building energy performance resilience requires also the assessment of energy needs under untypical boundary conditions. This implies the adoption of reference years remarkably warm...