Experimental performance of a dual-source heat pump coupled with shallow horizontal ground heat exchangers

The present paper analyses the preliminary results about the performance of a dual-source heat pump (DSHP), able to switch between air and ground according to operating rules for the air-conditioning system. The prototype is composed by a common air-to-air heat pump whose refrigerant circuit has been modified for coupling through a plate heat exchanger with a geothermal closed loop, laid horizontally and edgeways into a shallow trench. As ground heat exchanger (GHE), the Flat-Panel solution has been chosen due to its higher performance in comparison with similar GHEs, that makes this solution suitable for the issue. To over/underload the GHE system according the air conditioning energy load, the closed loop can be reduced by means of valves. The switching between air and ground is then automatized with a control unit which controls valves according to rules based on air and ground temperature, air humidity, and frosting conditions at the evaporator. The prototype is fully monitored in terms of temperatures, pressures, flow rate and electricity supply, both at the refrigerant circuit and the closed loop. Moreover, a dedicated monitoring system collects data about weather conditions, ground temperature at several depths and distances from the Flat-Panels, and finally their heat flux. The heating performance of the DSHP is taken in comparison with the standard air-source solution, with evidence of the better behaviour, even for a closed loop drastically partialized.peer-reviewe

Smart Control of Air Climatization System in Function on the Values of Mean Local Radiant Temperature

The hygrothermal comfort indoor conditions are defined as: those environmental conditions in which an individual exposed, expresses a state of satisfaction. These conditions cannot always be achieved anywhere in an optimal way and economically; in some cases they can be obtained only in work environments specific areas. This could be explained because of air conditioning systems designing is generally performed both on the basis of the fundamental parameters' average values, such as temperature, velocity and relative humidity (T-a, v(a) e phi(a)) and derived parameters such as operating temperature and mean radiant one (T-op eT(mr)). However, in some specific cases - large open-spaces or in case of radiating surfaces - the descriptors defining indoor comfort conditions, based on average values, do not provide the optimum values required during the air conditioning systems design phase. This is largely due to the variability of real environmental parameters values compared to the average ones taken as input in the calculation. The results obtained in previous scientific papers on the thermal comfort have been the driving element of this work. It offers a simple, original and clever way of thinking about the new domotic systems for air conditioning, based on the "local mean radiant temperature." This is a very important parameter when one wants to analyze comfort in environments characterized by the presence of radiating surfaces, as will be seen hereinafter. In order to take into account the effects of radiative exchanges in the open-space workplace, where any occupant may find themselves in different temperature and humidity conditions, this paper proposes an action on the domotic climate control, with ducts and vents air distribution placed in different zones. Comparisons were performed between the parameters values representing the punctual thermal comfort, with the Predicted Mean Vote PMV, in an environment marked by radiating surfaces (i.e continuous glass) and calculated with the local radiant temperature suggested in previous works, with the corresponding values obtained always varying the air speed or the air temperature inflated from the air vents, in order to achieve the optimal comfort conditions

Indoor comfort in presence radiant exchanges with insolated glassed walls and local acclimatization to increase indoor comfort conditions

The years ‘60 have been the starting point on an important R&D activity on the technologies for increasing the indoor comfort conditions. This activity produced related standards, such as ISO7730 an important technological research on domotics and different sensors for controlling indoor acclimatization parameters (temperature, humidity, air speed, etc.) at room level. They produced automatic controls and home automation systems allow managing and control acclimatization at room level. These technical solutions still present difficulties in managing the comfort conditions in large open-space office environments. The thermal uniformity problems are accentuated by the presence of large glassed surfaces. Such architectural conditions generate an uneven thermal distribution because of solar radiation that generates some consequent levels of localized discomfort. It is then evident that an effective optimization of the comfort conditions is much more important when we consider that this architectural design is often used in offices and other working environments. Different shading solutions have been studied with limited success. Previous research activities have introduced a new physical parameter defined as "local mean radiant temperature" that allows a better evaluation of comfort conditions inside large open space environments. This intuition produces an effective local acclimatization system, which grants an effective localized control of comfort conditions in large environments with large glassed surfaces. After an effective analysis of different methods for evaluating the comfort conditions according to actual standards, it evaluates the difference and the influence of the distance from the radiating surface. In conclusion, an effective solution for improving the thermal distribution This plant is realized by two fundamental subsystems: a Wi-Fi sensing subsystem that senses airspeed and temperature and a active conditioning system made by active reversible Peltier cells. The sensing system pilots the active local acclimatization inside the "open-space" environment. In this way, it increases the comfort conditions and the air quality with remarkable energy saving with respect to any traditional air-conditioning plant. The nature of the Peltier cells produces the same effect of a micro heat pump that produces localized and punctual HVAC. An effective increase in comfort conditions has been evaluated by means of the traditional parameters, such as PMV and PPD in different conditions of work

Evaluation of the sound emissions and climate acoustic in proximity of one railway station

In Europe, the acceptance of the railways as a driving force for the development economic and ecological it is subject at the rail noise reduction, aspect important for people's health and the environment. The acceptance of the noise for the citizens, living in the vicinity of railway lines, is of vital importance in view of the increasing number of trains and consequently of the noise they produce. Therefore, measures to reduce the noise levels are essential to prevent health risks in the citizens exposed. Health effects due to prolonged exposure to environmental noise, rarely can cause directly damage to hearing (hearing loss). Many damages psychosomatic, can affect the apparatus: digestive, respiratory, visual, reproductive, skin and circulatory systems and blood. Precisely for these reasons, in recent decades the actions of assessment and reduction of noise, coming from the civil engineering infrastructure, have become of paramount importance and cannot longer be neglected. The aim of this study is the evaluation of noise emission coming from a railway yard inserted in an urban context, and the acoustic environment in the surrounding area and the possible presence of sources concomitants in the railway area. The work presented here is part of a larger project aimed at developing a 3-D numerical model of the survey area, to be used for the noise-mapping of the area in the existing situation, both for the simulation of future order, resulting after the inclusion of noise abatement systems aimed at reducing noise pollution

Analysis of air pollution in the urban center of four cities sicilian

The process of urbanization in this new millennium is characterized by the fact that more than three quarters of Europe's population is concentrated in urban areas, thus it becomes essential the issue of how to reconcile the development of our cities with the respect and protection of the environment. Polluting vehicle emissions constitute a major contribution to the deterioration of urban air quality and represent a potential risk to public health of citizens. The qualitative improvement of processes of production it is to be considered in the near future, a priority for urban pollution reduction and for improving the quality of life of our cities. This paper shows the air pollution analysis of the urban center of four Sicilian city, and the concentrations of the critical pollutants (PM10â\u88\u97NO2â\u88\u97SOâ\u88\u97O3â\u88\u97COâ\u88\u97C6H6â\u88\u97NH3â\u88\u97COVNM.). Linear regressions were performed to represent the relationships between the main pollutants; they were analyzed also the differences between the concentrations of pollutants, and their progress over the years

Islands "smart energy" for eco-sustainable energy a case study "Favignana Island"

The term "Smart" in the last decade has often flanked other words to express a new and intelligent way of living in a modern society where you cannot separate the two synergic aspects: Energy and Sustainability. These latter two aspects flow into the new way of managing an isolated territory that often presents difficulties because of no interactions with the surrounding area; to remedy these difficulties has been developed in recent years the "Smart-Island" project, which involves many European countries and several sponsors. The concept of "Smart-Island" defines a way of life in an isolated environment, such as that of these islands, can solve independently, with the use of renewable and sustainable sources the energy needs of the island, with some projects that take into account the preservation and the wealth of the territory. In this paper, after a brief review of what has been proposed in some islands of the world, it will develop a case study, represented by the island of Favignana, which has particular characteristics in relation to its energy dependence

The local media radiant temperature for the calculation of comfort in areas characterized by Radiant surfaces

Thermo-hygrometric indoor conditions, as well known in literature, depend on the indices directly measurable in the place (Tba, Tbu, Ï\u86a, Va) and analytical solutions (Tmr, Top) and also on subjective assessments, metabolic activity carried out, and thermal resistance of clothing. They are tied to the subject occupied position within the work environment, substantially. In air conditioned rooms designed by systems with average parameters, it may happen that an individual, in some places or times, may feel sensations of thermal discomfort. These phenomena can be exacerbated by heat exchanges occurring in the presence of sources of radiation, such as radiant floors or ceilings or large glass surfaces sunny; these surfaces accentuate the radiative heat exchange with the body surfaces of the exposed individual. This paper proposes a "local mean radiant temperature" valid for the regular calculation of comfort in environments characterized by the presence of radiating surfaces. The present study compares the values of the parameters representing the hygrothermal comfort punctual, PMV, in environments characterized by radiating surfaces located in specific positions (ceiling, floor or walls), calculated with the local radiant temperature suggested in this study, with the corresponding values obtained with the mean radiant temperature proposed by the literature

Reducing the demand of energy cooling in the CED, "centers of Processing Data", with use of free-cooling systems

The data processing centers (CED) are defined today among the areas with the greatest demand for energy for specific use, and for the intrinsic operation of the technological equipment of processing and the data transmission. As a result of the high diffusion of today's telecommunications systems, the CEDs are increasingly widely disseminated and characterized by logics of operation, such as to ensure a high level of reliability in terms of continuity of service. Objective of the proposed study is to evaluate the reduction of demand energy by cooling, through implementation of air conditioning technologies based on air-conditioning systems of free-cooling type. The study compares different operating scenarios in relation to hypothetical operating conditions, in different regions of Italy characterized by different environmental thermo-hygrometric conditions, highlighting the limiting factors in terms of energy demand